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+<body>
+<div style='text-align:center'>*** START OF THE PROJECT GUTENBERG EBOOK 75389 ***</div>
+
+<hr class="chap x-ebookmaker-drop">
+
+<h1><span class="fs_80">PRINCIPLES AND PRACTICE<br> OF</span><br>AGRICULTURAL ANALYSIS.</h1>
+
+<hr class="r60">
+<p class="center">A MANUAL FOR THE EXAMINATION OF SOILS,<br>
+FERTILIZERS, AND AGRICULTURAL PRODUCTS.</p>
+
+<hr class="r60">
+<p class="center">FOR THE USE OF ANALYSTS, TEACHERS, AND<br>
+STUDENTS OF AGRICULTURAL CHEMISTRY.</p>
+
+<p class="f120 spa2 spb1">VOLUME III.</p>
+
+<p class="f120 spb2"><b>AGRICULTURAL PRODUCTS.</b></p>
+
+<p class="f120"><b>BY HARVEY W. WILEY,</b></p>
+<p class="f90"><span class="smcap">Chemist of the U. S. Department of Agriculture.</span>.</p>
+
+<hr class="r60">
+<p class="center">EASTON, PA.<br><span class="smcap">Chemical Publishing Co.</span><br>
+1897.</p>
+
+<p class="center">COPYRIGHT, 1897,<br><span class="smcap">By Harvey W. Wiley</span>.</p>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p class="f150"><b>PREFACE TO VOLUME THIRD.</b></p>
+</div>
+
+<p>The concluding volume of the Principles and Practice of Agricultural
+Analysis has been written in harmony with the plan adopted at the
+commencement of the first volume. In it an effort has been made to
+place the analyst or student <i>en rapport</i> with all the best
+methods of studying the composition of agricultural products. During
+the progress of the work the author has frequently been asked why
+some special method in each case has not been designated as the
+proper one to be used. To do this would be a radical departure from
+the fundamental idea of the work; <i>viz.</i>, to rely on the good
+judgment and experience of the chemist. It is not likely that the
+author’s judgment in such matters is better than that of the analyst
+using the book, and, except for beginning students pursuing a course
+of laboratory instruction, a biased judgment is little better than
+none at all. For student’s work in the laboratory or classroom it is
+probable that a volume of selected methods based on the present work
+may be prepared later on, but this possible future need has not been
+allowed to change the purpose of the author as expressed in the preface
+of the second volume “to present to the busy worker a broad view of a
+great subject.” For the courtesy and patience of the publishers, for
+the uniformly commendatory notices of the reviewers of volumes one and
+two, and for the personal encouraging expressions of his professional
+brethren the author is sincerely grateful. He finds in this cordial
+reception of his book a grateful compensation for long years of
+labor. The plates of the first edition of the three volumes have been
+destroyed in order to insure a re-writing of the second edition when it
+shall be demanded, in order to keep it abreast of the rapid progress in
+the field of agricultural chemical analysis.</p>
+
+<p><span class="smcap">Washington, D. C.</span>,<br>
+&nbsp;&emsp;Beginning of January, 1897.</p>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum"><a id="Page_iv"></a>[Pg iv]</span></p>
+<p class="f150"><b>TABLE OF CONTENTS OF<br> VOLUME THIRD.</b></p>
+</div>
+
+<div class="blockquot">
+<p class="f120 spa1"><b>PART FIRST.</b></p>
+<p class="f110">SAMPLING, DRYING, INCINERATION<br> AND EXTRACTIONS.</p>
+
+<p class="neg-indent"><i>Introduction</i>, <a href="#Page_1">pp. 1-3</a>.—Methods
+of study; Scope of the work; Limitations of work; General manipulations.</p>
+
+<p class="neg-indent"><i>Methods of Sampling</i>, <a href="#Page_3">pp. 3-13</a>.—Vegetable
+substances; Animal substances; Preserving samples; Collecting samples;
+Grinding samples; Grinding apparatus.</p>
+
+<p class="neg-indent"><i>Drying Organic Bodies</i>, <a href="#Page_13">pp. 13-36</a>.—Volatile
+bodies; Drying ovens; Air baths; Drying in vacuum; Electric drying
+ovens; Steam coil apparatus; Drying in hydrogen; Drying in tubes;
+Drying viscous liquids; General principles of drying.</p>
+
+<p class="neg-indent"><i>Incineration</i>, <a href="#Page_36">pp. 36-40</a>.—Principles
+of incineration; Products of combustion; Purpose and conduct of
+incineration; German ash method; Courtonne’s muffle.</p>
+
+<p class="neg-indent"><i>Extraction of Organic Bodies</i>,
+<a href="#Page_40">pp. 40-57</a>.—Object of extraction; Solvents;
+Methods of extraction; Extraction by digestion; Extraction by
+percolation; Apparatus for extraction; Knorr’s extraction apparatus;
+Soxhlet’s extraction apparatus; Compact extraction apparatus; Recovery
+of solvents; Authorities cited in Part First.</p>
+
+<p class="f120 spa1"><b>PART SECOND.</b></p>
+<p class="f110">SUGARS AND STARCHES.</p>
+
+<p class="neg-indent"><i>Introduction</i>, <a href="#Page_58">pp. 58-62</a>.—Carbohydrates;
+Nomenclature; Preparation of pure sugar; Classification of methods of analysis.</p>
+
+<p class="neg-indent"><i>Analysis by Density of Solution</i>,
+<a href="#Page_63">pp. 63-72</a>.—Principles of the method;
+Pyknometers; Calculating volume of pyknometers; Hydrostatic balance;
+Areometric method; Correction for temperature; Brix hydrometer;
+Comparison of brix and baumé degrees; Errors due to impurities.</p>
+
+<p class="neg-indent"><i>Estimation of Sugars with Polarized Light</i>,
+<a href="#Page_74">pp. 74-120</a>.—Optical properties of sugars;
+Polarized light; Nicol prism; Polariscope; Kinds of polariscopes;
+Character of light; Description of polarizing instruments:
+Laurent polariscope; Polariscope lamps; <span class="pagenum"><a
+id="Page_v"></a>[Pg v]</span> Soleil-Ventzke polariscope; Half Shadow
+polariscope; Triple field polariscope; Setting the polariscope;
+Control observation tube; Quartz plates; Correcting quartz plates;
+Application of quartz plates; Sugar flasks; Preparing sugar solutions
+for polarization; Alumina cream; Errors due to lead solutions; Double
+polarization; Mercuric compounds; Bone-black; Inversion of sugar;
+Clerget’s method; Influence of strength of solution; Calculation of
+results; Method of Lindet; Use of invertase; Activity of invertase;
+Inversion by yeast; Determination of sucrose; Determination of
+raffinose; Specific rotatory power; Calculating specific rotatory
+power; Variations in specific rotatory power; Gyrodynatic data; Birotation.</p>
+
+<p class="neg-indent"><i>Chemical Methods of Estimating Sugar</i>,
+<a href="#Page_120">pp. 120-149</a>.—General principles; Classification
+of methods; Reduction of mercuric salts; Sachsse’s solution; Volumetric
+copper methods; Action of copper solution on dextrose; Fehling’s
+solution; List of copper solutions; Volumetric laboratory method;
+Filtering tubes; Correction of errors; Permanganate process; Modified
+permanganate method; Specific gravity of cuprous oxid; Soldaini’s
+process; Relation of reducing sugar to quantity of suboxid; Factors for
+different sugars; Pavy’s process; Peska’s process; Method of Allein and
+Gaud; Method of Gerrard; Sidersky’s modification; Titration of excess
+of copper.</p>
+
+<p class="neg-indent"><i>Gravimetric Copper Methods</i>,
+<a href="#Page_149">pp. 149-170</a>.—General principles; Laboratory
+copper method; Halle method; Allihn’s method; Meissl’s method;
+Determination of invert sugar; Estimation of milk sugar; Determination
+of maltose; Preparation of levulose; Estimation of levulose.</p>
+
+<p class="neg-indent"><i>Miscellaneous Methods of Sugar Analysis</i>,
+<a href="#Page_171">pp. 171-196</a>; Phenylhydrazin; Molecular weights
+of carbohydrates; Birotation; Estimation of pentosans; Determination of
+furfurol; Method of Tollens; Method of Stone; Method of Chalmot; Method
+of Krug; Precipitation with pyrogalol; Precipitation with phloroglucin;
+Fermentation methods; Estimating alcohol; Estimating carbon dioxid;
+Precipitation with earthy bases; Barium saccharate; Strontium
+saccharate; Calcium saccharate; Qualitive tests; Optical tests;
+Cobaltous nitrate test; The Dextrose group; Tests for levulose; Tests
+for galactose; Tests for invert sugar; Compounds with phenylhydrazin;
+Detection of sugars by means of furfurol; Bacterial action on sugars.</p>
+
+<p class="neg-indent"><i>Determination of Starch</i>,
+<a href="#Page_196">pp. 196-226</a>.—Constitution of starch;
+Separation of starch; Methods of separation; Separation with diastase;
+Separation in an autoclave; Principles of analysis; Estimation of
+water; Estimation of ash; Estimation of nitrogen; Hydrolysis with
+acids; Factors for calculation; Polarization of starch; Solution at
+high pressure; Method of Hibbard; Precipitation with barium hydroxid;
+Disturbing bodies in starch determinations; Colorimetric estimation of
+starch; Fixation of iodin; Identification of starches; Vogel’s table;
+Muter’s table; Blyth’s classification; Preparation of starches for
+the microscope; Mounting in canada balsam; Description of typical
+starches; Authorities cited in Part Second.
+<span class="pagenum"><a id="Page_vi"></a>[Pg vi]</span></p>
+
+<p class="f120 spa1"><b>PART THIRD.</b></p>
+<p class="f110">SEPARATION AND DETERMINATION<br>
+OF CARBOHYDRATES IN CRUDE OR<br> MANUFACTURED AGRICULTURAL PRODUCTS.</p>
+
+<p class="neg-indent"><i>Sugars in Vegetable Juices</i>,
+<a href="#Page_227">pp. 227-253</a>.—Introduction; Sugar in the sap of
+trees; Sugar in sugar canes; Weighing pipettes; Gravimeter; Reducing
+sugars in juices; Preservation of juices; Direct estimation of sugar;
+Cutting or shredding canes; Methods of analysis; Drying and extracting;
+Examination of bagasse; Fiber in canes; Sugar beets; Estimation of
+sugar in sugar beets; Machines for pulping beets; Instantaneous
+diffusion; Pellet’s process; Alcohol digestion; Extraction with
+alcohol; Determination of sugar in mother beets; Determination of
+sugars without weighing; Continuous observation tube.</p>
+
+<p class="neg-indent"><i>Analysis of Sirups and Massecuites</i>,
+<a href="#Page_254">pp. 254-264</a>.—Specific gravity; Determination
+of water; Determination of ash; Determination of reducing sugars;
+Estimation of minute quantities of invert sugar; Soldaini’s gravimetric
+method; Weighing the copper as oxid; Analyses for factory control.</p>
+
+<p class="neg-indent"><i>Separation of Carbohydrates in Mixtures</i>,
+<a href="#Page_264">pp. 264-292</a>.—Occurrence of sugars; Optical
+methods; Optical neutrality of invert sugar; Separation of sucrose
+and invert sugar; Separation of sucrose and raffinose; Determination
+of levulose; Formula for calculating levulose; Separation of sucrose
+from dextrose; Estimation of lactose in milk; Error due to volume of
+precipitate; Separation of sucrose, levulose and dextrose; Sieben’s
+method; Wiechmann’s method; Copper carbonate method; Winter’s process;
+Separation with lead oxid; Analysis of commercial glucose and grape
+sugar; Fermentation method; Oxidation method; Removal of dextrose by
+copper acetate; Separation of dextrin with alcohol.</p>
+
+<p class="neg-indent"><i>Carbohydrates in Milk</i>,
+<a href="#Page_293">pp. 293-298</a>.—Copper tartrate method; The
+official method; The copper cyanid process; Separation of sugars in
+evaporated milks; Method of Bigelow and McElroy.</p>
+
+<p class="neg-indent"><i>Separation and Determination of Starch and
+Fiber</i>, <a href="#Page_298">pp. 298-306</a>.—Occurrence;
+Separation of starch; Dry amyliferous bodies; Indirect method of
+determining water; Removal of oils and sugars; Preparation of diastase;
+Estimation of starch in potatoes; Constitution of cellulose; Fiber
+in cellulose; Official method; Separation of cellulose: Solubility
+of cellulose; Qualitive reactions for cellulose; Rare carbohydrates;
+Authorities cited in Part Third.
+<span class="pagenum"><a id="Page_vii"></a>[Pg vii]</span></p>
+
+<p class="f120 spa1"><b>PART FOURTH.</b></p>
+<p class="f110">FATS AND OILS.</p>
+
+<p class="neg-indent"><i>General Principles</i>,
+<a href="#Page_309">pp. 309-316</a>.—Nomenclature; Composition;
+Principal glycerids; Presses for extraction; Solvents; Freeing extracts
+of petroleum; Freeing fats of moisture; Sampling and drying for
+analysis; Estimation of water.</p>
+
+<p class="neg-indent"><i>Physical Properties of Fats and Oils</i>,
+<a href="#Page_317">pp. 317-350</a>.—Specific gravity; Balance
+for determining specific gravity; Expression of specific gravity;
+Coefficient of expansion of oils; Densities of common fats and oils;
+Melting point; Determination in capillary tube; Determination by
+spheroidal state; Solidifying point; Temperature of crystallization;
+Refractive power; Refractive index; Abbe’s refractometer; Pulfrich’s
+refractometer; Refractive indices of common oils; Oleorefractometer;
+Butyrorefractometer; Range of application of the butyrorefractometer;
+Viscosity; Torsion viscosimeter; Microscopic appearance; Preparation
+of fat crystals; Observation of fat crystals with polarized light;
+Spectroscopic examination of oils; Critical temperature; Polarization;
+Turbidity temperature.</p>
+
+<p class="neg-indent"><i>Chemical Properties of Fats and Oils</i>,
+<a href="#Page_351">pp. 351-406</a>.—Solubility in alcohol; Coloration
+produced by oxidants; Nitric acid coloration; Phosphomolybdic acid
+coloration; Picric acid coloration; Silver nitrate coloration; Stannic
+bromid coloration; Auric chlorid coloration; Thermal reactions; Heat
+of sulfuric saponification; Maumené’s process; Method of Richmond;
+Relative maumené figure; Heat of bromination; Method of Hehner and
+Mitchell; Author’s method; Haloid addition numbers; Hübl number;
+Character of chemical reaction; Solution in carbon tetrachlorid;
+Estimation of the iodin number; Use of iodin monochlorid; Preservation
+of the hübl reagent; Bromin addition number; Method of Hehner;
+Halogen absorption by fat acids; Saponification; Saponification
+in an open dish; Saponification under pressure; Saponification in
+the cold; Saponification value; Saponification equivalent; Acetyl
+value; Determination of volatile fat acids; Removal of the alcohol;
+Determination of soluble and insoluble fat acids; Formulas for
+calculation; Determination of free fat acids; Identification of oils
+and fats; Nature of fat acids; Separation of glycerids; Separation
+with lime; Separation with lead salts; Separation of arachidic acid;
+Detection of peanut oil; Bechi’s test; Milliau’s test; Detection of
+sesamé oil; Sulfur chlorid reaction; Detection of cholesterin and
+phytosterin; Absorption of oxygen; Elaidin reactions; Authorities cited
+in Part Fourth.</p>
+
+<p class="f120 spa1"><b>PART FIFTH.</b></p>
+<p class="f110">SEPARATION AND ESTIMATION OF BODIES<br> CONTAINING NITROGEN.</p>
+
+<p class="neg-indent"><i>Introduction and Definitions</i>,
+<a href="#Page_410">pp. 410-418</a>.—Nature of nitrogenous bodies;
+Classification of proteids; Albuminoids; Other forms of nitrogen;
+Occurrence of nitrates.</p>
+
+<p class="neg-indent"><i>Qualitive Tests for Nitrogenous Bodies</i>,
+<a href="#Page_418">pp. 418-422</a>.—Nitric acid; Amid
+nitrogen; Ammoniacal nitrogen; Proteid <span class="pagenum"><a
+id="Page_viii"></a>[Pg viii]</span> nitrogen; Qualitive tests for
+albumni; Qualitive tests for peptones and albuminates; Action of
+polarized light on albumins; Alkaloidal nitrogen.</p>
+
+<p class="neg-indent"><i>Estimation of Nitrogenous Bodies in Agricultural
+Products</i>, <a href="#Page_423">pp. 423-432</a>.—Total nitrogen;
+Ammoniacal nitrogen; Amid nitrogen; Sachsse’s method; Preparation of
+asparagin; Estimation of asparagin and glutamin; Cholin and betain;
+Lecithin; Factors for calculating results; Estimation of alkaloidal
+nitrogen.</p>
+
+<p class="neg-indent"><i>Separation of Proteid Bodies in Vegetable
+Products</i>, <a href="#Page_432">pp. 432-448</a>.—Preliminary
+treatment; Character of proteids; Separation of gluten; Extraction with
+water; Action of water on composition of proteids; Extraction with
+dilute salt solution; Separation of bodies soluble in water; Separation
+of the globulins; Proteids soluble in dilute alcohol; Solvent action of
+acids and alkalies; Method of extraction; Methods of drying separated
+proteids; Determination of ash; Determination of carbon and hydrogen;
+Estimation of nitrogen; Determination of sulfur; Dialysis.</p>
+
+<p class="neg-indent"><i>Separation and Estimation of Nitrogenous
+Bodies in Animal Products</i>, <a href="#Page_448">pp. 448-462</a>.—Preparation
+of sample; Extraction of muscular tissues; Composition of meat extracts;
+Analysis of meat extracts; Use of phosphotungstic acid; Separation of
+albumoses and peptones; Estimation of gelatin; Estimation of nitrogen
+in flesh bases; Treatment of residue insoluble in alcohol; Pancreas
+peptone; Albumose peptone; Authorities cited in Part Fifth.</p>
+
+<p class="f120 spa1"><b>PART SIXTH.</b></p>
+<p class="f110">DAIRY PRODUCTS.</p>
+
+<p class="neg-indent"><i>Milk</i>, <a href="#Page_464">pp. 464-512</a>.—Composition
+of milk; Alterability of milk; Effects of boiling on milk;
+Micro-organisms of milk; Sampling milk; Scovell’s milk sampler;
+Preserving milk for analysis; Freezing point; Electric conductivity;
+Viscosity; Acidity and alkalinity; Determination of acidity; Opacity;
+Creamometry; Specific gravity; Lactometry; Quévenne lactometer;
+Lactometer of the New York Board of Health; Density of sour milk;
+Density of milk serum; Total solids; Formulas for calculating total
+solids; Determination of ash; Estimation of fat; Fat globules; Number
+of fat globules; Counting globules; Classification of methods of
+analysis; Dry extraction methods; Official methods; Variations of
+extraction methods; Gypsum method; Estimation of fat in malted milk;
+Comparison of fat methods; Wet extraction methods; Solution in acid;
+Solution in alkali; Method of Short; Method of Thörner; Liebermann’s
+method; Densimetric methods; Areometric methods; Lactobutyrometer;
+Volumetric methods of fat analysis; Method of Patrick; The lactocrite;
+Modification of Lindström; Babcock’s method; Method of Leffmann and
+Beam; Method of Gerber; Proteid bodies in milk; Estimation of total
+<span class="pagenum"><a id="Page_ix"></a>[Pg ix]</span>
+proteid matter; Copper sulfate as a reagent; Precipitation by ammonium
+sulfate; Precipitation by tannic acid; Separation of casein from
+albumin; Estimation of casein; Factors for calculation; Separation of
+casein; Separation of casein with carbon dioxid; Separation of albumin;
+Separation of globulin; Precipitants of milk proteids; Precipitation
+by dialysis; Carbohydrates in milk; Dextrinoid body in milk; Amyloid
+bodies in milk.</p>
+
+<p class="neg-indent"><i>Butter</i>, <a href="#Page_512">pp. 512-523</a>.—General
+principles of analysis; Appearance of melted butter; Microscopic examination;
+Refractive power; Estimation of water, fat, casein, ash and salt;
+Volatile and soluble acids; Relative proportion of glycerids;
+Saponification value; Reichert number; Reichert-Meissl method;
+Elimination of sulfurous acid; Errors due to poor glass; Molecular
+weight of butter; Substitutes for and adulterants of butter; Butter colors.</p>
+
+<p class="neg-indent"><i>Cheese and Koumiss</i>,
+<a href="#Page_524">pp. 524-536</a>.—Composition of cheese; Manufacture
+of cheese; Official methods of analysis; Process of Mueller; Separation
+of fat from cheese; Filled cheese; Separation of nitrogenous bodies;
+Preparation of koumiss; Determination of carbon dioxid; Acidity;
+Estimation of alcohol; Proteids in koumiss; Separation by porous
+porcelain; Separation by precipitation with alum; Separation with
+mercury salts; Determination of water and ash; Composition of koumiss;
+Authorities cited in Part Sixth.</p>
+
+<p class="f120 spa1"><b>PART SEVENTH.</b></p>
+<p class="f110">MISCELLANEOUS AGRICULTURAL PRODUCTS.</p>
+
+<p class="neg-indent"><i>Cereals and Cereal Foods</i>,
+<a href="#Page_541">pp. 541-545</a>.— Classification; General methods
+of analysis; Composition and analysis of bread; Determination of alum
+in bread; Chemical changes produced by baking.</p>
+
+<p class="neg-indent"><i>Fodders, Grasses, and Ensilage</i>,
+<a href="#Page_545">pp. 545-547</a>.—General principles of analysis;
+Organic acids in ensilage; Changes due to fermentation; Alcohol in
+ensilage; Comparative values of dry fodder and ensilage.</p>
+
+<p class="neg-indent"><i>Flesh Products</i>,
+<a href="#Page_547">pp. 547-555</a>.—Names of meats; Sampling; General
+methods of analysis; Examination of nitrogenous bodies; Fractional
+analysis of meats; Starch in meats; Detection of horse flesh.</p>
+
+<p class="neg-indent"><i>Methods of Digestion</i>,
+<a href="#Page_555">pp. 555-564</a>.—Artificial digestion; Amylolytic
+ferments; Aliphalytic ferments; Proteolytic ferments; Pepsin and
+pancreatin; Digestion in pancreas extract; Artificial digestion of
+cheese; Natural digestion; Digestibility of pentosans.</p>
+
+<p class="neg-indent"><i>Preserved Meats</i>,
+<a href="#Page_565">pp. 565-566</a>.—Methods of examination; Estimation
+of fat; Meat preservatives.</p>
+
+<p class="neg-indent"><i>Determination of Nutritive Values</i>,
+<a href="#Page_566">pp. 566-576</a>.—Nutritive value of foods;
+Comparative value of food constituents; Nutritive ratio; Calorimetric
+analysis of foods; Combustion in oxygen; Bomb calorimeter; Manipulation
+and calculation; Computing the calories of combustion; Calorimetric
+equivalents; Distinction between butter and oleomargarin.
+<span class="pagenum"><a id="Page_x"></a>[Pg x]</span></p>
+
+<p class="neg-indent"><i>Fruits, Melons and Vegetables</i>,
+<a href="#Page_577">pp. 577-582</a>.— Preparation of samples;
+Separation of carbohydrates; Examination of the fresh matter;
+Examination of fruit and vegetable juices; Separation of pectin;
+Determination of free acid; Composition of fruits; Composition of ash
+of fruits; Dried fruits; Zinc in evaporated fruits; Composition of
+melons.</p>
+
+<p class="neg-indent"><i>Tea and Coffee</i>,
+<a href="#Page_582">pp. 582-588</a>.—Special points in analysis;
+Estimation of caffein; Iodin method; Spencer’s method; Separation
+of chlorophyll; Determination of proteid nitrogen; Carbohydrates of
+coffee; Estimation of galactan; Revised factors for pentosans; Use of
+roentgen rays.</p>
+
+<p class="neg-indent"><i>Tannins and Allied Bodies</i>,
+<a href="#Page_588">pp. 588-596</a>.— Occurrence and composition;
+Detection and estimation; Precipitation with metallic salts; The
+gelatin method; The hide powder method; Permanganate gelatin method;
+Permanganate hide powder method; Preparation of infusion.</p>
+
+<p class="neg-indent"><i>Tobacco</i>, <a href="#Page_596">pp. 596-610</a>.—Fermented
+and unfermented tobacco; Acid and basic constituents; Composition of ash;
+Composition of tobacco; Estimation of water; Estimation of nitric acid;
+Estimation of sulfuric and hydrochloric acids; Estimation of oxalic,
+malic and citric acids; Estimation of acetic acid; Estimation of pectic
+acid; Estimation of tannic acid; Estimation of starch and sugar;
+Estimation of ammonia; Estimation of nicotin; Polarization method of
+Popovici; Estimation of amid nitrogen; Fractional extraction; Burning
+qualities; Artificial smoker.</p>
+
+<p class="neg-indent"><i>Fermented Beverages</i>,
+<a href="#Page_610">pp. 610-641</a>.— Description; Important
+constituents; Specific gravity; Determination of alcohol; Distilling
+apparatus; Specific gravity of the distillate; Hydrostatic plummet;
+Calculating results; Table giving percentage of alcohol by weight
+and volume; Determination of percentage of alcohol by means of vapor
+temperature; Improved ebullioscope; Indirect determination of extract;
+Determination of total acids; Determination in a vacuum; Estimation
+of water; Total acidity; Volatile acids; Tartaric acid; Tartaric,
+malic and succinic acids; Polarizing bodies in fermented beverages;
+Reducing sugars; Polarization of wines and beers; Application of
+analytical methods; Estimation of carbohydrates; Determination of
+glycerol; Coloring matters; Determination of ash; Determination of
+potash; Sulfurous acid; Salicylic acid; Detection of gum and dextrin;
+Determination of nitrogen; Substitutes for hops; Bouquet of fermented
+and distilled liquors; Authorities cited in Part Seventh;
+<a href="#Page_645">Index</a>.</p>
+</div>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum"><a id="Page_xi"></a>[Pg xi]</span></p>
+<p class="f120"><b>ILLUSTRATIONS TO<br> VOLUME THIRD.</b></p>
+</div>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdr fs_90" colspan="6">Page.</td>
+   </tr><tr>
+      <td class="tdl">Figure</td>
+      <td class="tdr">1.</td>
+      <td class="tdl_wsp" colspan="3">Mill for grinding dry samples</td>
+      <td class="tdr"><a href="#FIG_1">7</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">2.</td>
+      <td class="tdl_wsp" colspan="3">Comminutor for green samples</td>
+      <td class="tdr"><a href="#FIG_2">9</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">3.</td>
+      <td class="tdl_wsp" colspan="3">Rasp for sugar beets</td>
+      <td class="tdr"><a href="#FIG_3">10</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">4.</td>
+      <td class="tdl_wsp" colspan="3">Dreef grinding apparatus</td>
+      <td class="tdr"><a href="#FIG_4">11</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">5.</td>
+      <td class="tdl_wsp" colspan="3">Water jacket drying oven</td>
+      <td class="tdr"><a href="#FIG_5">14</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">6.</td>
+      <td class="tdl_wsp" colspan="3">Thermostat for Steam-Bath</td>
+      <td class="tdr"><a href="#FIG_6">15</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">7.</td>
+      <td class="tdl_wsp" colspan="3">Spencer’s drying oven</td>
+      <td class="tdr"><a href="#FIG_7">17</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">8.</td>
+      <td class="tdl_wsp" colspan="3">Electric vacuum drying oven</td>
+      <td class="tdr"><a href="#FIG_8">19</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">9.</td>
+      <td class="tdl_wsp" colspan="3">Steam coil drying oven</td>
+      <td class="tdr"><a href="#FIG_9">21</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">10.</td>
+      <td class="tdl_wsp" colspan="3">Carr’s vacuum drying oven</td>
+      <td class="tdr"><a href="#FIG_10A">22</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">10.</td>
+      <td class="tdl_wsp" colspan="3">(Bis.) vacuum oven open</td>
+      <td class="tdr"><a href="#FIG_10B">23</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">11.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for drying in a current of hydrogen</td>
+      <td class="tdr"><a href="#FIG_11">25</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">12.</td>
+      <td class="tdl_wsp" colspan="3">Caldwell’s hydrogen drying apparatus</td>
+      <td class="tdr"><a href="#FIG_12">27</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">13.</td>
+      <td class="tdl_wsp" colspan="3">Liebig’s ente</td>
+      <td class="tdr"><a href="#FIG_13">28</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">14.</td>
+      <td class="tdl_wsp" colspan="3">Drying apparatus used at the Halle Station</td>
+      <td class="tdr"><a href="#FIG_14">29</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">15.</td>
+      <td class="tdl_wsp" colspan="3">Wrampelmayer’s oven</td>
+      <td class="tdr"><a href="#FIG_15">30</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">16.</td>
+      <td class="tdl_wsp" colspan="3">Ulsch drying oven</td>
+      <td class="tdr"><a href="#FIG_16">31</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">17.</td>
+      <td class="tdl_wsp" colspan="3">Courtoune muffle</td>
+      <td class="tdr"><a href="#FIG_17">39</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">18.</td>
+      <td class="tdl_wsp" colspan="3">Knorr’s extraction apparatus</td>
+      <td class="tdr"><a href="#FIG_18">45</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">19.</td>
+      <td class="tdl_wsp" colspan="3">Extraction flask</td>
+      <td class="tdr"><a href="#FIG_19">46</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">20.</td>
+      <td class="tdl_wsp" colspan="3">Extraction tube</td>
+      <td class="tdr"><a href="#FIG_20">46</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">21.</td>
+      <td class="tdl_wsp" colspan="3">Extraction siphon tube</td>
+      <td class="tdr"><a href="#FIG_21">46</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">22.</td>
+      <td class="tdl_wsp" colspan="3">Soxhlet extraction apparatus</td>
+      <td class="tdr"><a href="#FIG_22">48</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">23.</td>
+      <td class="tdl_wsp" colspan="3">Compact condensing apparatus</td>
+      <td class="tdr"><a href="#FIG_23">49</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">24.</td>
+      <td class="tdl_wsp" colspan="3">Improved compact extraction apparatus</td>
+      <td class="tdr"><a href="#FIG_24">51</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">25.</td>
+      <td class="tdl_wsp" colspan="3">Knorr’s apparatus for recovering solvents</td>
+      <td class="tdr"><a href="#FIG_25">54</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">26.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for recovering solvents from open dishes</td>
+      <td class="tdr"><a href="#FIG_26">55</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">27.</td>
+      <td class="tdl_wsp" colspan="3">Common forms of pyknometers</td>
+      <td class="tdr"><a href="#FIG_27">63</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">28.</td>
+      <td class="tdl_wsp" colspan="3">Bath for pyknometers</td>
+      <td class="tdr"><a href="#FIG_28">66</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">29.</td>
+      <td class="tdl_wsp" colspan="3">Aereometers, pyknometers and hydrostatic balance</td>
+      <td class="tdr"><a href="#FIG_29">68</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">30.</td>
+      <td class="tdl_wsp" colspan="3">Hydrostatic balance</td>
+      <td class="tdr"><a href="#FIG_30">69</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">31.</td>
+      <td class="tdl_wsp" colspan="3">Course of rays of light in a nicol</td>
+      <td class="tdr"><a href="#FIG_31">77</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">32.</td>
+      <td class="tdl_wsp" colspan="3">Theory of the nicol</td>
+      <td class="tdr"><a href="#FIG_32">78</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">33.</td>
+      <td class="tdl_wsp" colspan="3">Laurent lamp</td>
+      <td class="tdr"><a href="#FIG_33">83</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">34.</td>
+      <td class="tdl_wsp" colspan="3">Lamp for producing constant monochromatic flame</td>
+      <td class="tdr"><a href="#FIG_34">85</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">35.</td>
+      <td class="tdl_wsp" colspan="3">Field of vision of a Laurent polariscope</td>
+      <td class="tdr"><a href="#FIG_35">86</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">36.</td>
+      <td class="tdl_wsp" colspan="3">Laurent polariscope</td>
+      <td class="tdr"><a href="#FIG_36">88</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">37.</td>
+      <td class="tdl_wsp" colspan="3">Tint polariscope</td>
+      <td class="tdr"><a href="#FIG_37">89</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">38.</td>
+      <td class="tdl_wsp" colspan="3">Double compensating shadow polariscope</td>
+      <td class="tdr"><a href="#FIG_38">91</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">39.</td>
+      <td class="tdl_wsp" colspan="3">Triple shadow polariscope</td>
+      <td class="tdr"><a href="#FIG_39">92</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">40.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for producing a triple shadow</td>
+      <td class="tdr"><a href="#FIG_40">92</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">41.</td>
+      <td class="tdl_wsp" colspan="3">Control observation tube</td>
+      <td class="tdr"><a href="#FIG_41">95</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">42.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for the volumetric estimation</td>
+      <td class="tdr">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdr">&nbsp;</td>
+      <td class="tdl_ws2" colspan="3">of reducing sugars</td>
+      <td class="tdr"><a href="#FIG_42">131</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">43.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for the electrolytic deposition of copper</td>
+      <td class="tdr"><a href="#FIG_43">151</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">44.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for filtering copper suboxid</td>
+      <td class="tdr"><a href="#FIG_44">154</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">45.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for reducing copper suboxid</td>
+      <td class="tdr"><a href="#FIG_45">154</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">46.</td>
+      <td class="tdl_wsp" colspan="3">Distilling apparatus for pentoses</td>
+      <td class="tdr"><a href="#FIG_46">179</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">47.</td>
+      <td class="tdl_wsp" colspan="3">Autoclave for starch analysis</td>
+      <td class="tdr"><a href="#FIG_47A">199</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">47.</td>
+      <td class="tdl_wsp bb" colspan="3">(Bis). Maercker’s hydrolyzing apparatus for starch</td>
+      <td class="tdr bb"><a href="#FIG_47B">204</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">48.</td>
+      <td class="tdl_ws2"><a href="#FIG_48">Maranta starch</a></td>
+      <td class="tdl">× 350</td>
+      <td class="tdl bb" rowspan="14">to face</td>
+      <td class="tdr bb" rowspan="14">220</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">49.</td>
+      <td class="tdl_ws2"><a href="#FIG_49">Potato starch</a></td>
+      <td class="tdl">× 350</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">50.</td>
+      <td class="tdl_ws2"><a href="#FIG_50">Ginger starch</a></td>
+      <td class="tdl">× 350</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">51.</td>
+      <td class="tdl_ws2"><a href="#FIG_51">Sago starch</a></td>
+      <td class="tdl">× 350</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">52.</td>
+      <td class="tdl_ws2"><a href="#FIG_52">Pea starch</a></td>
+      <td class="tdl">× 350</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">53.</td>
+      <td class="tdl_ws2"><a href="#FIG_53">Bean starch</a></td>
+      <td class="tdl">× 350</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">54.</td>
+      <td class="tdl_ws2"><a href="#FIG_54">Wheat starch</a></td>
+      <td class="tdl">× 350</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">55.</td>
+      <td class="tdl_ws2"><a href="#FIG_55">Barley starch</a></td>
+      <td class="tdl">× 350</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">56.</td>
+      <td class="tdl_ws2"><a href="#FIG_56">Rye starch</a></td>
+      <td class="tdl">× 350</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">57.</td>
+      <td class="tdl_ws2"><a href="#FIG_57">Oat starch</a></td>
+      <td class="tdl">× 350</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">58.</td>
+      <td class="tdl_ws2"><a href="#FIG_58">Indian corn starch</a></td>
+      <td class="tdl">× 350</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">59.</td>
+      <td class="tdl_ws2"><a href="#FIG_59">Rice starch</a></td>
+      <td class="tdl">× 350</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">60.</td>
+      <td class="tdl_ws2"><a href="#FIG_60">Cassava starch</a></td>
+      <td class="tdl">× 150</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">61.</td>
+      <td class="tdl_ws2 bb"><a href="#FIG_61">Indian corn starch</a></td>
+      <td class="tdl bb">× 150
+            <span class="pagenum"><a id="Page_xii"></a>[Pg xii]</span></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">62.</td>
+      <td class="tdl_wsp" colspan="3">Laboratory cane mill</td>
+      <td class="tdr"><a href="#FIG_62">230</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">63.</td>
+      <td class="tdl_wsp" colspan="3">Weighing pipette</td>
+      <td class="tdr"><a href="#FIG_63">231</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">64.</td>
+      <td class="tdl_wsp" colspan="3">Gird’s gravimeter</td>
+      <td class="tdr"><a href="#FIG_64">233</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">65.</td>
+      <td class="tdl_wsp" colspan="3">Machine for cutting canes</td>
+      <td class="tdr"><a href="#FIG_65">236</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">66.</td>
+      <td class="tdl_wsp" colspan="3">Cane cutting mill</td>
+      <td class="tdr"><a href="#FIG_66">237</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">67.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for pulping beets</td>
+      <td class="tdr"><a href="#FIG_67">243</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">68.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for cold diffusion</td>
+      <td class="tdr"><a href="#FIG_68">245</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">69.</td>
+      <td class="tdl_wsp" colspan="3">Sickel-Soxhlet extractor</td>
+      <td class="tdr"><a href="#FIG_69">247</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">70.</td>
+      <td class="tdl_wsp" colspan="3">Scheibler’s extraction tube</td>
+      <td class="tdr"><a href="#FIG_70">248</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">71.</td>
+      <td class="tdl_wsp" colspan="3">Battery for alcoholic digestion</td>
+      <td class="tdr"><a href="#FIG_71">250</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">72.</td>
+      <td class="tdl_wsp" colspan="3">Rasp for sampling mother beets</td>
+      <td class="tdr"><a href="#FIG_72">251</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">73.</td>
+      <td class="tdl_wsp" colspan="3">Hand press for beet analysis</td>
+      <td class="tdr"><a href="#FIG_73">251</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">74.</td>
+      <td class="tdl_wsp" colspan="3">Perforating rasp</td>
+      <td class="tdr"><a href="#FIG_74">252</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">75.</td>
+      <td class="tdl_wsp" colspan="3">Tube for continuous observation</td>
+      <td class="tdr"><a href="#FIG_75A">253</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">75.</td>
+      <td class="tdl_wsp" colspan="3">(Bis). Chandler and Rickett’s Polariscope</td>
+      <td class="tdr"><a href="#FIG_75B">266</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">76.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for polarimetric observations</td>
+      <td class="tdr">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdr">&nbsp;</td>
+      <td class="tdl_ws2" colspan="3">at low temperatures</td>
+      <td class="tdr"><a href="#FIG_76">267</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">77.</td>
+      <td class="tdl_wsp" colspan="3">Construction of desiccating tube</td>
+      <td class="tdr"><a href="#FIG_77">268</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">78.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for polarizing at high temperatures</td>
+      <td class="tdr"><a href="#FIG_78">269</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">79.</td>
+      <td class="tdl_wsp" colspan="3">Oil press</td>
+      <td class="tdr"><a href="#FIG_79">312</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">80.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for fractional distillation</td>
+      <td class="tdr">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdr">&nbsp;</td>
+      <td class="tdl_ws2" colspan="3">of petroleum ether</td>
+      <td class="tdr"><a href="#FIG_80">314</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">81.</td>
+      <td class="tdl_wsp" colspan="3">Section showing construction of a funnel</td>
+      <td class="tdr">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdr">&nbsp;</td>
+      <td class="tdl_ws2" colspan="3">for hot filtration</td>
+      <td class="tdr"><a href="#FIG_81">316</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">82.</td>
+      <td class="tdl_wsp" colspan="3">Balance and Westphal sinker</td>
+      <td class="tdr"><a href="#FIG_82">318</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">83.</td>
+      <td class="tdl_wsp" colspan="3">Melting point tubes</td>
+      <td class="tdr"><a href="#FIG_83">322</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">84.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for the determination of melting point</td>
+      <td class="tdr"><a href="#FIG_84">324</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">85.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for determining crystallizing point</td>
+      <td class="tdr"><a href="#FIG_85">327</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">86.</td>
+      <td class="tdl_wsp" colspan="3">Abbe’s refractometer</td>
+      <td class="tdr"><a href="#FIG_86">329</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">87.</td>
+      <td class="tdl_wsp" colspan="3">Charging position of refractometer</td>
+      <td class="tdr"><a href="#FIG_87">330</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">88.</td>
+      <td class="tdl_wsp" colspan="3">Prism of Pulfrich’s refractometer</td>
+      <td class="tdr"><a href="#FIG_88">331</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">89.</td>
+      <td class="tdl_wsp" colspan="3">Pulfrich’s new refractometer</td>
+      <td class="tdr"><a href="#FIG_89">332</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">90.</td>
+      <td class="tdl_wsp" colspan="3">Heating apparatus for Pulfrich’s refractometer</td>
+      <td class="tdr"><a href="#FIG_90">333</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">91.</td>
+      <td class="tdl_wsp" colspan="3">Spectrometer attachment</td>
+      <td class="tdr"><a href="#FIG_91">333</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">92.</td>
+      <td class="tdl_wsp" colspan="3">Oleorefractometer</td>
+      <td class="tdr"><a href="#FIG_92">335</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">93.</td>
+      <td class="tdl_wsp" colspan="3">Section showing construction of oleorefractometer</td>
+      <td class="tdr"><a href="#FIG_93">335</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">94.</td>
+      <td class="tdl_wsp" colspan="3">Butyrorefractometer</td>
+      <td class="tdr"><a href="#FIG_94">339</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">95.</td>
+      <td class="tdl_wsp bb" colspan="3">Doolittle’s viscosimeter</td>
+      <td class="tdr bb"><a href="#FIG_95">343</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">96.</td>
+      <td class="tdl_ws2"><a href="#FIG_96">Lard crystals</a></td>
+      <td class="tdl">× 65</td>
+      <td class="tdl bb" rowspan="2">to face</td>
+      <td class="tdr bb" rowspan="2">348</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">97.</td>
+      <td class="tdl_ws2 bb"><a href="#FIG_97">Refined lard crystals</a></td>
+      <td class="tdl bb">× 65</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">98.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for determining rise of temperature</td>
+      <td class="tdr">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdr">&nbsp;</td>
+      <td class="tdl_ws2" colspan="3">with sulfuric acid</td>
+      <td class="tdr"><a href="#FIG_98">358</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">99.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for determining heat of bromination</td>
+      <td class="tdr"><a href="#FIG_99">362</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">100.</td>
+      <td class="tdl_wsp" colspan="3">Olein tube</td>
+      <td class="tdr"><a href="#FIG_100">374</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">101.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for saponifying under pressure</td>
+      <td class="tdr"><a href="#FIG_101">380</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">102.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for the distillation of volatile acids</td>
+      <td class="tdr"><a href="#FIG_102">388</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">103.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for amid nitrogen</td>
+      <td class="tdr"><a href="#FIG_103">425</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">104.</td>
+      <td class="tdl_wsp" colspan="3">Sachsse’s eudiometer</td>
+      <td class="tdr"><a href="#FIG_104">425</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">105.</td>
+      <td class="tdl_wsp" colspan="3">Dialyzing apparatus</td>
+      <td class="tdr"><a href="#FIG_105">447</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">106.</td>
+      <td class="tdl_wsp" colspan="3">Scovell’s milk sampling tube</td>
+      <td class="tdr"><a href="#FIG_106">470</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">107.</td>
+      <td class="tdl_wsp" colspan="3">Lactoscope, lactometer, and creamometer</td>
+      <td class="tdr"><a href="#FIG_107">474</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">108.</td>
+      <td class="tdl_wsp" colspan="3">Areometric fat apparatus</td>
+      <td class="tdr"><a href="#FIG_108">493</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">109.</td>
+      <td class="tdl_wsp" colspan="3">Babcock’s butyrometer and acid measure</td>
+      <td class="tdr"><a href="#FIG_109">500</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">110.</td>
+      <td class="tdl_wsp" colspan="3">Gerber’s butyrometers</td>
+      <td class="tdr"><a href="#FIG_110">502</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">111.</td>
+      <td class="tdl_wsp" colspan="3">Gerber’s centrifugal</td>
+      <td class="tdr"><a href="#FIG_111">503</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">112.</td>
+      <td class="tdl_wsp" colspan="3">Thermometer for butyrorefractometer</td>
+      <td class="tdr"><a href="#FIG_112">515</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">113.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for determining carbon dioxid in koumiss</td>
+      <td class="tdr"><a href="#FIG_113">533</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">114.</td>
+      <td class="tdl_wsp" colspan="3">Cuts of mutton</td>
+      <td class="tdr"><a href="#FIG_114">548</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">115.</td>
+      <td class="tdl_wsp" colspan="3">Cuts of beef</td>
+      <td class="tdr"><a href="#FIG_115">548</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">116.</td>
+      <td class="tdl_wsp" colspan="3">Cuts of pork</td>
+      <td class="tdr"><a href="#FIG_116">548</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">117.</td>
+      <td class="tdl_wsp" colspan="3">Bath for artificial digestion</td>
+      <td class="tdr"><a href="#FIG_117">559</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">118.</td>
+      <td class="tdl_wsp" colspan="3">Bag for collecting feces</td>
+      <td class="tdr"><a href="#FIG_118">563</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">119.</td>
+      <td class="tdl_wsp" colspan="3">Fecal bag attachment</td>
+      <td class="tdr"><a href="#FIG_119">563</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">120.</td>
+      <td class="tdl_wsp" colspan="3">Hempel and Atwater’s calorimeter</td>
+      <td class="tdr"><a href="#FIG_120">570</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">121.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for acetic acid</td>
+      <td class="tdr"><a href="#FIG_121">603</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">122.</td>
+      <td class="tdl_wsp" colspan="3">Apparatus for smoking</td>
+      <td class="tdr"><a href="#FIG_122">610</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">123.</td>
+      <td class="tdl_wsp" colspan="3">Metal distilling apparatus</td>
+      <td class="tdr"><a href="#FIG_123">613</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">124.</td>
+      <td class="tdl_wsp" colspan="3">Distilling apparatus</td>
+      <td class="tdr"><a href="#FIG_124">614</a></td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdr">125.</td>
+      <td class="tdl_wsp" colspan="3">Improved ebullioscope</td>
+      <td class="tdr"><a href="#FIG_125">623</a></td>
+   </tr>
+ </tbody>
+</table>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum"><a id="Page_1"></a>[Pg 1]</span></p>
+<p class="f150"><b>VOLUME THIRD.</b></p>
+<p class="f120"><b>AGRICULTURAL PRODUCTS.</b></p>
+<hr class="chap x-ebookmaker-drop">
+
+<h2 class="nobreak">PART FIRST.<br>
+<span class="h_subtitle">SAMPLING, DRYING, INCINERATION<br>AND EXTRACTIONS.</span></h2>
+</div>
+
+<p><b>1. Introduction.</b>—The analyst may approach the examination of
+agricultural products from various directions. In the first place
+he may desire to know their proximate and ultimate constitution
+irrespective of their relations to the soil or to the food of man and
+beast. Secondly, his study of these products may have reference solely
+to the determination of the more valuable plant foods which they have
+extracted from the soil and air. Lastly, he may approach his task from
+a hygienic or economic standpoint for the purposes of determining the
+wholesomeness or the nutritive and economic values of the products
+of the field, orchard, or garden. In each case the object of the investigation
+will have a considerable influence on the method of the examination.</p>
+
+<p>It will be the purpose of the present volume to discuss fully the
+principles of all the standard processes of analysis and the best
+practice thereof, to the end that the investigator or analyst, whatever
+may be the design of his work, may find satisfactory directions for
+prosecuting it. As in the previous volumes, it should be understood
+that these pages are written largely for the teacher and the analyst
+already skilled in the principles of analytical chemistry. Much is
+therefore left to the individual judgment and experience of the worker,
+to whom it is hoped a judicious choice of approved processes may be
+made possible.</p>
+
+<p><b>2. Scope Of the Work.</b>—Under the term agricultural products
+is included a large number of classes of bodies of most different
+constitution. In general they are the products of vegetable and animal
+<span class="pagenum"><a id="Page_2"></a>[Pg 2]</span>
+metabolism. First of all come the vegetable products, fruits, grains
+and grasses. These may be presented in their natural state, as cereals,
+green fruits and fodders, or after a certain preparation, as starches,
+sugars and flours. They may also be met with in even more advanced
+stages of change, as cooked foods, alcohols and secondary organic
+acids, such as vinegar. In general, by the term agricultural products
+is meant not only the direct products of the farm, orchard and forest,
+but also the modified products thereof and the results of manufacture
+applied to the raw materials. Thus, not only the grain and straw of
+wheat are proper materials for agricultural analysis, but also flour
+and bran, bread and cakes made therefrom. In the case of maize and
+barley, the manufactured products may extend much further, for not only
+do we find starch and malt, but also alcohol and beer falling within
+the scope of our work. In respect of animal products, the agricultural
+analyst may be called on to investigate the subject of leather and
+tanning; to determine the composition of meat, milk and butter; to
+pass upon the character of lard, oleomargarine, and, in general, to
+determine as fully as possible the course of animal food in all its
+changes between the field, the packing house and the kitchen.</p>
+
+<p><b>3. Limitations of Work.</b>—It is evident from the preceding
+paragraph, that in order to keep the magnitude of this volume within
+the limits fixed for a single volume the text must be rigidly confined
+to the fundamental principles and practice of agricultural analysis.
+The interesting region of pharmacy and allied branches, in respect of
+plant analysis, can find no description here, and in those branches
+of technical chemistry, where the materials of elaboration are the
+products of the field only a superficial view can be given. The main
+purpose and motive of this volume must relate closely to the more
+purely agricultural processes.</p>
+
+<p><b>4. General Manipulations.</b>—There are certain analytical
+operations which are more or less of a general nature, that is, they
+are of general application without reference to the character of the
+material at hand. Among these may be mentioned the determination of
+<span class="pagenum"><a id="Page_3"></a>[Pg 3]</span>
+moisture and of ash, and the estimation of matters soluble in ether,
+alcohol and other solvents. These processes will be first described.
+Preliminary to these analytical steps it is of the utmost importance
+that the material be properly prepared for examination. In general,
+this is accomplished by drying the samples until they can be ground
+or crushed to a fine powder, the attrition being continued until
+all the particles are made to pass a sieve of a given fineness. The
+best sieve for this purpose is one having circular apertures half a
+millimeter in diameter. Some products, both vegetable and animal,
+require to be reduced to as fine a state as possible without drying.
+In such instances, passing the product through a sieve is obviously
+impracticable. Special grinding and disintegrating machines are made
+for these purposes and they will be described further on.</p>
+
+<p>There are some agricultural products which have to be prepared for
+examination in special ways and these methods will be given in
+connection with the processes for analyzing the bodies referred
+to. Nearly all the bodies, however, with which the analyst will be
+concerned, can be prepared for examination by the general methods about
+to be described.</p>
+
+<p id="P_5"><b>5. Preparation of the Sample.</b> (<i>a</i>) <i>Vegetable
+Substances.</i>—For all processes of analysis not executed on the
+fresh sample, substances of a vegetable nature should, if in a fresh
+state, be dried as rapidly as possible to prevent fermentative changes.
+It is often of interest to determine the percentage of moisture in
+the fresh sample. For this purpose a representative portion of the
+sample should be rapidly reduced to as fine a condition as possible.
+To accomplish this it should be passed through a shredding machine,
+or cut by scissors or a knife into fine pieces. A few grams of the
+shredded material are dried in a flat-bottomed dish at progressively
+increasing temperatures, beginning at about 60° and ending at from 100°
+to 110°. The latter temperature should be continued for only a short
+time. The principle of this process is based upon the fact that if the
+temperature be raised too high at first, some of the moisture in the
+interior cells of the vegetable substance can be occluded by the too
+rapid desiccation of the exterior layers which would take place at a
+high temperature. The special processes for determining moisture will
+be given in another place.
+<span class="pagenum"><a id="Page_4"></a>[Pg 4]</span></p>
+
+<p>The rest of the sample should be partly dried at a lower temperature
+or air-dried. In the case of fodders and most cattle foods the samples
+come to the analyst in a naturally air-dried state. When grasses are
+harvested at a time near their maturity they are sun-dried in the
+meadows before placing in the stack or barn. Such sun-dried samples are
+already in a state fit for grinding. Green grasses and fodders should
+be dried in the sun, or in a bath at a low temperature from 50° to
+60° until all danger of fermentative action is over, and then air- or
+sun-dried in the usual way.</p>
+
+<p>Seeds and cereals usually reach the analyst in a condition suited to
+grinding without further preliminary preparation. Fruits and vegetables
+present greater difficulties. Containing larger quantities of water,
+and often considerable amounts of sugar, they are dried with greater
+difficulty. The principles which should guide all processes of drying
+are those already mentioned, <i>viz.</i>, to secure a sufficient degree
+of desiccation to permit of fine grinding and at a temperature high
+enough to prevent fermentative action, and yet not sufficiently high to
+cause any marked changes in the constituents of the vegetable organism.</p>
+
+<p>(<i>b</i>) <i>Animal Substances.</i>—The difficulties connected with
+the preliminary treatment of animal substances are far greater than
+those just mentioned. Such samples are composed of widely differing
+tissues, blood, bone, tendon, muscle and adipose matters, and all the
+complex components of the animal organism are to be considered. The
+whole animal may be presented for analysis, in which case the different
+parts composing it should be separated and weighed as exactly as
+possible. Where only definite parts are to be examined it is best to
+separate the muscle, bone, and fat as well as may be, before attempting
+to reduce the whole to a fine powder. The soft portions of the sample
+are to be ground as finely as possible in a meat or sausage cutter.
+The bones are crushed in some appropriate manner, and thus prepared
+for further examination. Where the flesh and softer portions are to be
+dried and finely ground, the presence of fat often renders the process
+almost impossible. In such cases the fat must be at least partially
+<span class="pagenum"><a id="Page_5"></a>[Pg 5]</span>
+removed by petroleum or other solvent. In practically fat-free samples
+the material, after grinding in a meat cutter, can be partially dried
+at low temperatures from 60° to 75°, and afterwards ground in much the
+same manner as is practiced with vegetable substances.</p>
+
+<p>As is the case with the preliminary treatment of vegetable matters,
+it is impossible to give any general directions of universal
+applicability. The tact and experience of the analyst in all these
+cases are better than any dicta of the books. In some instances, as
+will appear further on, definite directions for given substances can be
+given, but in all cases the general principles of procedure are on the
+lines already indicated.</p>
+
+<p><b>6. Preserving Samples.</b>—In most cases, as is indicated in the
+foregoing paragraphs, the sample may be dried before grinding to such a
+degree as to prevent danger from fermentation or decay. The fine-ground
+samples are usually preserved in glass-stoppered bottles, carefully
+marked or numbered. In some cases it is advisable to sterilize the
+bottles after stoppering, by subjecting them to a temperature of 100°
+for some time. In the case of cereals assurance should be had that the
+samples do not contain the eggs of any of the pests that often destroy
+these products. As a rule, samples should be kept for a time after the
+completion of the analytical work, and this is especially true in all
+cases where there is any prospect of dispute or litigation. In general
+it may be said, that samples should be destroyed only when they are
+spoiled, or when storage room is exhausted.</p>
+
+<p><b>7. Collecting Samples.</b>—When possible, the analyst should be
+his own collector. There is often as much danger from data obtained
+on non-representative samples as from imperfect manipulation. When
+personal supervision is not possible, the sample when received,
+should be accompanied by an intelligible description of the method of
+taking it, and of what it represents. In all cases the object of the
+examination must be kept steadily in view. Where comparisons are to be
+made the methods of collecting must be rigidly the same.</p>
+
+<p>The processes of analysis, as conducted with agricultural products, are
+tedious and difficult. The absolutely definite conditions that attend
+the analysis of mineral substances, are mostly lacking. The simple
+<span class="pagenum"><a id="Page_6"></a>[Pg 6]</span>
+determinations of carbon, hydrogen, nitrogen and sulfur, which are
+required in the usual processes of organic analysis, are simplicity
+itself when compared with the operations which have to be performed
+on agricultural products to determine their character and their value
+as food and raiment. We have to do here with matters on which the
+sustenance, health and prosperity of the human race are more intimately
+concerned than with any other of the sciences. This fact also
+emphasizes the necessity for care in collecting the materials on which
+the work is to be performed.</p>
+
+<p><b>8. Grinding Samples.</b>—In order to properly conduct the processes
+of agricultural analysis it is important to have the sample finely
+ground. This arises both from the fact that such a sample is apt
+to contain an average content of the various complex substances of
+which the material under examination is composed, and because the
+analytical processes can be conducted with greater success upon the
+finely divided matter. In mineral analysis it is customary to grind the
+sample to an impalpable powder in an agate mortar. With agricultural
+products, however, such a degree of fineness is difficult to attain,
+and moreover, is not necessary. There is a great difference of opinion
+among analysts respecting the degree of fineness desirable. In some
+cases we must be content with a sample which will pass a sieve with a
+millimeter mesh; in fact it may be found impossible, on account of the
+stickiness of the material, to sift it at all. In such cases a thorough
+trituration, so as to form a homogeneous mass will have to be accepted
+as sufficient. Where bodies can be reduced to a powder however, it
+is best to pass them through a sieve with circular perforations half
+a millimeter in diameter. A finer degree of subdivision than this is
+rarely necessary.</p>
+
+<p><b>9. The Grinding Apparatus.</b>—The simplest form of apparatus for
+reducing samples for analysis to a condition suited to passing a fine
+sieve is a mortar. Where only a few samples are to be prepared and in
+small quantities, it will not be necessary to provide anything further.
+After the sample is well disintegrated it is poured on the sieve and
+all that can pass is shaken or brushed through. The sieve is provided
+with a receptacle, into which it fits closely, to avoid loss of any
+particles which may be reduced to a dust. The top of the sieve, when
+<span class="pagenum"><a id="Page_7"></a>[Pg 7]</span>
+shaken, may also be covered if there be any tendency to loss from dust.
+Any residue failing to pass the sieve is returned to the mortar and
+the process thus repeated until all the material has been secured in
+the receiver. The particles more difficult of pulverization are often
+different in structure from the more easily pulverized portions, and
+the sifted matter must always be carefully mixed before the subsample
+is taken for examination. Often the materials, or portions thereof,
+will contain particles tough and resistant to the pestle, but the
+operator must have patience and persistence, for it is highly necessary
+to accurate work that the whole sample be reduced to proper size.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_1" src="images/fig1.jpg" alt="" width="600" height="406" >
+    <p class="center spb1">Figure 1. Mill for Grinding Dry Samples.</p>
+</div>
+
+<p>Where many samples are to be prepared, or in large quantities, mills
+should take the place of mortars. For properly air-dried vegetable
+substances, some form of mill used in grinding drugs may be employed.
+Grinding surfaces of chilled corrugated steel are to be preferred.
+The essential features of such a mill are that it be made of the best
+material, properly tempered, and that the parts be easily separated
+for convenience in cleaning. The grinding surfaces must also be so
+constructed and adjusted as to secure the proper degree of fineness. In
+<span class="pagenum"><a id="Page_8"></a>[Pg 8]</span>
+<a href="#FIG_1">fig. 1</a> is shown a mill of rather simple construction,
+which has long been in satisfactory use in this laboratory. Small mills may
+be operated by hand power, but when they are to be used constantly
+steam power should be provided. In addition to the removal of nearly
+all the moisture by air-drying there are many oleaginous seeds which
+cannot be finely ground until their oil has been removed. For this
+purpose the grinding surfaces of the mill are opened so that the seeds
+are only coarsely broken in passing through. The fragments are then
+digested with light petroleum in a large flask, furnished with a reflux
+condenser. After digestion the fragments are again passed through the
+mill adjusted to break them into finer particles.</p>
+
+<p>The alternate grinding and digestion are thus continued until the
+pulverization is complete. On a small specially prepared sample the
+total content of oil is separately determined.</p>
+
+<p>Fresh animal tissues are best prepared for preliminary treatment by
+passing through a sausage mill. The partially homogeneous mass thus
+secured should be dried at a low temperature and reground as finely as
+possible. Where much fat is present it may be necessary to extract it
+as mentioned above, in the case of oleaginous seeds. In such cases both
+the moisture and fat in the original material should be determined on
+small specially prepared samples with as great accuracy as possible.
+Bones, hoofs, horns, hair and hides present special difficulties in
+preparation, which the analyst will have to overcome with such skill
+and ingenuity as he may possess.</p>
+
+<p>The analyst will find many specially prepared animal foods already in
+a fairly homogeneous form, such as potted and canned meats, infant
+and invalid foods, and the like. Even with these substances, however,
+a preliminary grinding and mixing will be found of advantage before
+undertaking the analytical work. Many cases will arise which are
+apparently entirely without the classification given above. But even in
+such instances the analyst should not be without resources. Frequently
+some dry inert substance may be mixed with the material in definite
+quantities, whereby it is rendered more easily prepared. Perhaps no
+case will be presented where persistent and judicious efforts to secure
+a fairly homogeneous sample for analysis will be wholly unavailing.
+<span class="pagenum"><a id="Page_9"></a>[Pg 9]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_2" src="images/fig2.jpg" alt="" width="600" height="456" >
+    <p class="center spb1">Figure 2. Comminutor for Green Samples.</p>
+</div>
+
+<p>In the case of green vegetable matters which require to be reduced
+rapidly to a fine state of subdivision in order to secure even a fairly
+good sample some special provision must be made. This is the case
+with stalks of maize and sugar cane, root crops, such as potatoes and
+beets, and green fodders, such as clover and grasses. The chopping of
+these bodies into fine fodders by hand is slow and often impracticable.
+The particles rapidly lose moisture and it is important to secure
+them promptly as in the preparation of beet pulp for polarization.
+For general use we have found the apparatus shown in <a href="#FIG_2">fig. 2</a>
+quite satisfactory in this laboratory. It consists of a series of staggered
+circular saws carried on an axis and geared to be driven at a high
+velocity, in the case mentioned, 1,400 revolutions per minute. The
+green material is fed against the revolving saws by the toothed
+gear-work shown, and is thus reduced to a very fine pulp, which is
+received in the box below. Stalks of maize, green fodders, sugar canes,
+beets and other fresh vegetable matters are by this process reduced
+to a fine homogeneous pulp, suited for sampling and for analytical
+<span class="pagenum"><a id="Page_10"></a>[Pg 10]</span>
+operations. Such pulped material can also be spread in a fine layer
+and dried rapidly at a low temperature, thus avoiding danger of
+fermentative changes when it is desired to secure the materials in a
+dry condition or to preserve them for future examination. Samples of
+sorghum cane, thus pulped and dried, have been preserved for many years
+with their sugar content unchanged.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_3" src="images/fig3.jpg" alt="" width="400" height="378" >
+    <p class="center spb1">Figure 3. Rasp for Sugar Beets.</p>
+</div>
+
+<p>Such a machine is also useful in preparing vegetable matter for the
+separation of its juices in presses. Samples of sugar cane, sugar
+beets, apples and other bodies of like nature can thus be prepared to
+secure their juices for chemical examination. Such an apparatus we
+have found is fully as useful and indispensable in an agricultural
+laboratory as a drug mill for air-dried materials.</p>
+
+<p>It is often desirable in the preparation of roots for sugar analysis
+to secure them in a completely disintegrated state, that is with the
+cellular tissues practically all broken. Such a pulped material can
+be treated with water and the sugar juices it contains thus at once
+distributed to all parts of the liquid mass. The operation is known
+as instantaneous diffusion. The pulp of the vegetable matter is thus
+introduced into the measuring flask along with the juices and the
+content of sugar can be easily determined. Several forms of apparatus
+have been devised for this purpose, one of which is shown in <a href="#FIG_3">fig. 3</a>.
+This process, originally devised by Pellet, has come into quite general
+<span class="pagenum"><a id="Page_11"></a>[Pg 11]</span>
+use in the determination of the sugar content of
+beets.<a id="FNanchor_1" href="#Footnote_1" class="fnanchor">[1]</a>
+It is observed that it can be applied to other tubers, such as the
+turnip, potato, artichoke, etc. It is desirable, therefore, that an
+agricultural laboratory be equipped with at least three kinds of
+grinding machines; <i>viz.</i>, first, the common drug mill used for
+grinding seeds, air-dried fodders, and the like; second, a pulping
+machine like the system of staggered saws above described for the
+purpose of reducing green vegetable matter to a fine state of
+subdivision, or one like the pellet rasp for tubers; third, a mill for
+general use such as is employed for making sausages from soft animal tissues.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_4" src="images/fig4.jpg" alt="" width="400" height="410" >
+    <p class="center spb1">Figure 4. Dreef Grinding Apparatus.</p>
+</div>
+
+<p><b>10. Grinding Apparatus at Halle Station.</b>—The machine used at
+the Halle station for grinding samples for analysis is shown in
+<a href="#FIG_4">Fig. 4</a>.<a id="FNanchor_2" href="#Footnote_2" class="fnanchor">[2]</a>
+It is so adjusted as to have both the upper and lower grinding
+surfaces in motion. The power is transmitted through the pulley D,
+which is fixed to an axis carrying also the inner grinding attachment
+B. Through C₂, C₃, C₄, and C₁, the reverse motion is transmitted to
+the outer grinder A. By means of the lever E the two grinding surfaces
+can be separated when the mill is to be cleaned. The dree mill above
+described is especially useful for grinding malt, dry brewers’ grains,
+cereals for starch determinations and similar dry bodies. It is not
+<span class="pagenum"><a id="Page_12"></a>[Pg 12]</span>
+suited to grinding oily seeds and moist samples. These, according to
+the Halle methods, are rubbed up in a mortar until of a size suited to
+analysis, and samples such as moist residues, wet cereals, mashes, beet
+cuttings, silage, etc., are dried before grinding. If it be desired to
+avoid the loss of acids which may have been formed during fermentation,
+about ten grams of magnesia should be thoroughly incorporated with each
+kilogram of the material before drying.</p>
+
+<p><b>11. Preliminary Treatment of Fish.</b>—The method used by Atwater
+in preparing fish for analysis is given below.<a id="FNanchor_3" href="#Footnote_3" class="fnanchor">[3]</a>
+The same process may also be found applicable in the preparation of
+other animal tissues. The specimens, when received at the laboratory,
+are at once weighed. The flesh is then separated from the refuse and
+both are weighed. There is always a slight loss in the separation,
+due to evaporation and to slimy and fatty matters and small fragments
+of the tissues which adhere to the hands and the utensils employed in
+preparing the sample. Perfect separation of the flesh from the other
+parts of the fish is difficult, but the loss resulting from imperfect
+separation is small. The skin of the fish, although it has considerable
+nutritive value, should be separated with the other refuse.</p>
+
+<p>The partial drying of the flesh for securing samples for analytical
+work is accomplished by chopping it as finely as possible and
+subjecting from fifty to one hundred grams of it for a day to a
+temperature of 96° in an atmosphere of hydrogen. After cooling and
+allowing to stand in the open air for twelve hours, the sample is again
+weighed, and then ground to a fine powder and made to pass a sieve
+with a half millimeter mesh. If the samples be very fat they cannot
+be ground to pass so fine a sieve. In such a case a coarser sieve may
+be used or the sample reduced to as fine and homogeneous a state as
+possible, and bottled without sifting.</p>
+
+<p>The reason for drying in hydrogen is to prevent oxidation of the fats.
+As will be seen further on, however, such bodies can be quickly and
+accurately dried at low temperatures in a vacuum, and thus all danger
+of oxidation be avoided. In fact, the preliminary drying of all animal
+and vegetable tissues, where oxidation is to be feared, can be safely
+accomplished in a partial vacuum by methods to be described in another
+<span class="pagenum"><a id="Page_13"></a>[Pg 13]</span>
+place. In order to be able to calculate the data of the analysis to the
+original fresh state of the substance, a portion of the fresh material
+should have its water quantitively determined as accurately as possible.</p>
+
+<h3>DRYING ORGANIC BODIES.</h3>
+
+<p><b>12. Volatile Bodies.</b>—In agricultural analysis it becomes
+necessary to determine the percentage of bodies present in any given
+sample which is volatile at any fixed temperature. The temperature
+reached by boiling water is the one which is usually selected. It
+is true that this temperature varies with the altitude and within
+somewhat narrow limits at the same altitude, due to variations in
+barometric pressure. As the air pressure to which any given body is
+subjected, however, is a factor in the determination of its volatile
+contents, it will be seen that within the altitudes at which chemical
+laboratories are found, the variations in volatile content will not
+be important. This arises from the fact that while water boils at a
+lower temperature, as the height above the sea level increases, the
+corresponding diminished air pressure permits a more ready escape of
+volatile matter. As a consequence, a body dried to constant weight at
+sea level, where the temperature of boiling water is 100°, will show
+the same percentage of volatile matter as if dried at an altitude where
+water boils at 99°. When, therefore, it is desirable to determine the
+volatile matter in a sample approximately at 100°, it is better to
+direct that it be done in a space surrounded by steam at the natural
+pressure rather than at exactly 100°, a temperature somewhat difficult
+to constantly maintain. However, where it is directed or desired to
+dry to constant weight exactly at 100°, it can be accomplished by
+means of an air-bath or by a water-jacketed-bath under pressure, or to
+which enough solid matter is added to raise the boiling-point to 100°.
+It is not often, however, that it is worth while to make any special
+efforts to secure a temperature of 100°. When bodies are to be dried at
+temperatures above 100°, such as 105°, 110°, and so on, an air-bath is
+the most convenient means of securing the desired end. The different
+kinds of apparatus to be employed will be described in succeeding paragraphs.</p>
+
+<p><b>13. Drying at the Temperature of Boiling Water.</b>—The best
+<span class="pagenum"><a id="Page_14"></a>[Pg 14]</span>
+apparatus for this process is so constructed as to have an interior
+space entirely surrounded with boiling water or steam, with the
+exception of the door by which entrance is gained thereto. The metal
+parts of the apparatus are constructed of copper, and to keep a
+constant level of water and avoid the danger of evaporating all the
+liquid, it is advisable to have a reflux condenser attached to the
+apparatus. It is also well to secure entrance to the interior drying
+oven, not only by the door, but also by small circular openings, which
+serve both to hold a thermometer and to permit of the aspiration of a
+slow stream of dry air through the apparatus during the progress of
+desiccation. The gaseous bodies formed by the volatilization of the
+water and other matters are thus carried out of the drying box and the
+process thereby accelerated. The bath should be heated by a burner so
+arranged as to distribute the flame as evenly as possible over the
+base. A single lamp, while it will boil the water in the center, will
+not keep it at the boiling-point on the sides. The temperature of the
+interior of the bath will not therefore reach 100°. The interior of the
+oven should be coated with a non-detachable carbon paint to promote
+the radiation of the heat from its walls, as well as to protect the
+parts from oxidation where acid fumes are produced during desiccation.
+Instead of a reflux condenser a constant water level may be maintained
+in the bath by means of a mariotte bottle or other similar device.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_5" src="images/fig5.jpg" alt="" width="400" height="599" >
+    <p class="center spb1">Figure 5. Water-jacketed Drying Oven.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_15"></a>[Pg 15]</span>
+When a bath of this kind is arranged for use with a partial vacuum, it
+should be made cylindrical in shape, with conical ends, as shown in
+<a href="#FIG_5">fig. 5</a>, in order to bear well the pressure to
+which it is subjected. Among the many forms of steam-baths offered,
+the analyst will have but little difficulty in selecting one suited to
+his work. To avoid radiation the exterior of the apparatus should be
+covered with a non-conducting material.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_6" src="images/fig6.jpg" alt="" width="600" height="455" >
+    <p class="center spb1">Figure 6. Thermostat for Steam-Bath.</p>
+</div>
+
+<p><b>14. Drying In a Closed Water Oven.</b>—When it is desired to keep
+the temperature of a drying oven exactly at 100° instead of at the
+heat of boiling water, a closed water oven with a thermostat is to
+be employed. The oven should be so constructed as to secure a free
+circulation of the water about the inner space. Since as a rule the
+water between the walls of the apparatus will be subjected to a slight
+pressure, these walls should be made strong, or the cylindrical form
+of apparatus should be used. The thermostat used by the Halle Station
+is shown in <a href="#FIG_6">Fig. 6</a>.<a id="FNanchor_4" href="#Footnote_4" class="fnanchor">[4]</a>
+A <b>⋃</b> shaped tube, with a bulb on one arm and a lateral smaller
+tube sealed on the other, is partly filled with mercury and connected
+by rubber tubes on the right with the gas supply, and on the left with
+the burner. The end carrying the bulb is connected
+
+<span class="pagenum"><a id="Page_16"></a>[Pg 16]</span>
+directly by a rubber and metal tube with the water space of the oven.
+This device is provided with a valve which is left open until the
+temperature of the drying space reaches about 95°. The tube conducting
+the gas is held in the long arm of the <b>⋃</b> by means of a cork
+through which it passes air-tight and yet is loose enough to permit of
+its being moved. Its lower end is provided with a long ▲ shaped slit.
+When the valve leading to the water space is closed and the water
+reaches the boiling point, the pressure of the vapor depresses the
+mercury in the bulb arm of the <b>⋃</b> and raises it in the other. As
+the mercury rises it closes the wider opening of the ▲ shaped slit,
+thus diminishing the flow of gas to the burner. By moving the gas entry
+tube up or down a position is easily found in which the temperature of
+the drying space, as shown by the thermometer, is kept accurately and
+constantly at 100°.</p>
+
+<p>In a bath arranged in this way a steam condenser is not necessary.
+Since, however, in laboratories which are not at a higher altitude than
+1,000 feet the boiling-point of water is nearly 100°, it does not seem
+necessary to go to so much trouble to secure the exact temperature
+named. There could be no practical difference in the percentage of
+moisture determined at 100°, and at the boiling-point of water at a
+temperature not more than 1° lower.</p>
+
+<p><b>15. Drying in an Air-Bath.</b>—In drying a substance in a medium of
+hot air surrounded by steam, as has been described, the process is, in
+reality, one of drying in air. The apparatus usually meant by the term
+air-bath, however, has its drying space heated directly by a lamp, or
+indirectly by a stratum of hot air occupying the place of steam in the
+oven already described. The simplest form of the apparatus is a metal
+box, usually copper, heated from below by a lamp. In the jacketed forms
+the currents of hot air produced directly or indirectly by the lamp
+are conducted around the inner drying oven, thus securing a more even
+temperature. The bodies to be dried are held on perforated metal or
+asbestos shelves in appropriate dishes, and the temperature to which
+they are subjected is determined by a thermometer, the bulb of which is
+brought as near as possible to the contents of the dish. One advantage
+<span class="pagenum"><a id="Page_17"></a>[Pg 17]</span>
+of the air-bath is in being able to secure almost any desired
+temperature from that of the room to one of 150° or even higher. Its
+chief disadvantage lies in the difficulty of securing and maintaining
+an even temperature throughout all parts of the apparatus. Radiation
+from the sides of the drying oven should be prevented by a covering of
+asbestos or other non-combustible and non-conducting substance. The
+burner employed should be a broad one and give as even a distribution
+of the heat as possible over the bottom of the apparatus.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_7" src="images/fig7.jpg" alt="" width="500" height="417" >
+    <p class="center spb1">Figure 7. Spencer’s Drying Oven.</p>
+</div>
+
+<p><b>16. Spencer’s Air-Drying Oven.</b>—In order to secure an even
+distribution of the heat in the desiccating space of the oven, Spencer
+has devised an apparatus, <a href="#FIG_7">shown in the figure</a>, in which
+the temperature is maintained evenly throughout the apparatus by means of a
+fan.<a id="FNanchor_5" href="#Footnote_5" class="fnanchor">[5]</a>
+The oven has a double bottom, the space between the two bottoms being
+filled with air. The sides are also double, the space between being
+filled with plaster. The fan is driven by a toy engine connected with
+<span class="pagenum"><a id="Page_18"></a>[Pg 18]</span>
+the compressed air service or other convenient method. Thermometers
+placed in different parts of the apparatus, while in use, show a
+rigidly even heat at all points so long as the fan is kept in motion.
+The actual temperature desired can be controlled by a gas regulator.
+This form of apparatus is well suited to drying a large number of
+samples at once. Portions of liquids and viscous masses may also be
+dried by enclosing them in bulbs and connecting with a vacuum.</p>
+
+<p>Spencer’s oven can also be used to advantage in drying viscous
+liquids in a partial vacuum. For this purpose the flask A, <a href="#FIG_7">Fig. 7</a>,
+containing the substance is made with a round bottom to resist the
+atmospheric pressure. Its capacity is conveniently from 150 to 200
+cubic centimeters. It is closed with a rubber stopper carrying a trap,
+H Hʹ, to keep the evaporated water from falling back. The details of
+the construction of the trap H are shown at the right of the <a href="#FIG_7">figure</a>.
+The vapors enter at the lateral orifice, just above the bulb, while the
+condensed water falls back into the bulb instead of into the flask A. A
+series of flasks can be used at once connected through the stopcocks
+G with the circular tube E leading to the vacuum. A water pump easily
+exhausts the apparatus, maintaining a vacuum of about twenty-seven
+inches. The hot air in the oven is kept in motion by the fan B, thus
+ensuring an even temperature in every part. The flask A may be partly
+filled with sand or pumice stone before the addition of the samples
+to be dried, and the weight of water lost is determined by weighing
+A before and after desiccation. If it be desired to introduce a slow
+current of dry air or some inert gas into A, it is easily accomplished
+by passing a small tube, connected with the dry air or gas supply,
+through the rubber stopper and extending it into the flask as far as
+possible without coming into contact with the contents.</p>
+
+<p><b>17. Drying Under Diminished Air Pressure.</b>—The temperature at
+which any given body loses its volatile products is conditioned largely
+by the pressure to which it is subjected. At an air pressure of 760
+millimeters of mercury, water boils at 100° but it is volatilized at
+all temperatures. As the pressure diminishes the temperature at which a
+body loses water at a given rate falls. This is a fact of importance to
+be considered in drying many agricultural products. This is especially
+<span class="pagenum"><a id="Page_19"></a>[Pg 19]</span>
+true of those containing oils and sugars, nearly the whole number.
+Invert sugar especially is apt to suffer profound changes at a
+temperature of 100°, the levulose it contains undergoing partial
+decomposition. Oils are prone to oxidation and partial decomposition at
+high temperatures in the presence of oxygen.</p>
+
+<p>In drying in a partial vacuum therefore a double advantage is secured,
+that of a lower temperature of desiccation and in presence of less
+oxygen. It is not necessary to have a complete vacuum. There are few
+organic products which cannot be completely deprived of their volatile
+matters at a temperature of from 70° to 80° in a partial vacuum in
+which the air pressure has been diminished to about one-quarter of its
+normal force.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_8" src="images/fig8.jpg" alt="" width="500" height="483" >
+    <p class="center spb1">Figure 8. Electric Vacuum Drying Oven.</p>
+</div>
+
+<p><b>18. Electric Drying-Bath.</b>—The heat of an electric current can
+be conveniently used for drying in a partial vacuum by means of the
+<span class="pagenum"><a id="Page_20"></a>[Pg 20]</span>
+simple device illustrated in <a href="#FIG_8">Fig. 8</a>. In ordering
+a heater of this kind the voltage of the current should be stated. The
+current in use in this laboratory has a voltage of about 120, and is
+installed on the three wire principle. It is well to use a rheostat
+with the heater in order to control the temperature within the bell
+jar. The ground rim of the bell jar rests on a rubber disk placed on a
+thick ground glass or a metal plate, making an air-tight connection. A
+disk of asbestos serves to separate the heater from the dish containing
+the sample, in order to avoid too high a temperature.</p>
+
+<p><b>19. Steam Coil Apparatus.</b>—For drying at the temperature of
+superheated steam, it is convenient to use an apparatus furnished with
+layers or coils of steam pipes. The drying may be accomplished either
+in the air or in a vacuum. In this laboratory a large drying oven,
+having three shelves of brass steam-tubes and sides of non-conducting
+material, is employed with great advantage. The series of heating
+pipes is so arranged as to be used one at a time or collectively. Each
+series is furnished with a separate steam valve, and is provided with
+a trap to control the escape of the condensed vapors. In the bottom of
+the apparatus are apertures through which air can enter, which after
+passing through the interior of the oven escapes through a ventilator
+at the top. With a pressure of forty pounds of steam to the square inch
+and a free circulation of air, the temperature on the first shelf of
+the apparatus is about 98°; on the second from 103° to 104°, and on
+the third about 100°. The vessels containing the bodies to be dried
+are not placed directly on the brass steam pipes, but the latter are
+first covered with thick perforated paper or asbestos. For drying
+large numbers of samples, or large quantities of one sample, such an
+apparatus is almost indispensable to an agricultural laboratory.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_9" src="images/fig9.jpg" alt="" width="400" height="601" >
+    <p class="center spb1">Figure 9. Steam Coil Drying Oven.</p>
+</div>
+
+<p>A smaller apparatus is shown in <a href="#FIG_9">Fig. 9</a>. The heating part
+G is made of a small brass tube arranged near the bottom in a horizontal coil and
+continued about the sides in a perpendicular coil. Bodies placed on the
+horizontal shelf are thus entirely surrounded by the heating surfaces
+except at the top.<a id="FNanchor_6" href="#Footnote_6" class="fnanchor">[6]</a>
+The steam pipe S is connected with the supply by the usual method, and
+the escape of the condensation is controlled either by a valve or trap
+<span class="pagenum"><a id="Page_21"></a>[Pg 21]</span>
+in the usual way. The whole apparatus is covered by a bell jar B,
+resting on a heavy cast-iron plate P, through which also the ends of
+the brass coil pass. The upper surface of the iron plate may be planed,
+or a planed groove may be cut into it, to secure the edge of the bell
+jar. When the air is to be exhausted from the apparatus, a rubber
+<span class="pagenum"><a id="Page_22"></a>[Pg 22]</span>
+washer should be placed under the rim of the bell jar. The latter piece
+of apparatus may either be closed, as shown in the <a href="#FIG_9">figure</a>,
+by a rubber stopper, or it is better, though not shown, to have a stopper with
+three holes. One tube passes just through the stopper and is connected
+with the vacuum; the second passes to the bottom of the apparatus and
+serves to introduce a slow stream of dry air or of an inert gas during
+the desiccation. The third hole is for a thermometer. When no movement
+of the residual gas in the apparatus is secured, a dish containing
+strong sulfuric acid S’ is placed on the iron plate and under the
+horizontal coil, as is shown in the <a href="#FIG_9">figure</a>. The sulfuric acid
+so placed does not reach the boiling-point of water, and serves to absorb the
+aqueous vapors from the residual air in the bell jar. By controlling
+<span class="pagenum"><a id="Page_23"></a>[Pg 23]</span>
+the steam supply the desiccation of a sample can be secured in
+the apparatus at any desired temperature within the limit of the
+temperature of steam at the pressure used. Where no steam service is at
+hand a strong glass flask may be used as a boiler, in which case the
+trap end of the coil must be left open. The vacuum may be supplied by
+an air or bunsen pump. When a vacuum is not used an atmosphere of dry
+hydrogen may be supplied through H.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_10A" src="images/fig10.jpg" alt="" width="400" height="425" >
+    <p class="center spb1">Figure 10. Carr’s Vacuum Drying Oven.</p>
+
+    <img id="FIG_10B" src="images/fig10_2.jpg" alt="" width="400" height="468" >
+    <p class="center spb1">Figure 10. (Bis) Vacuum Oven Open.</p>
+</div>
+
+<p id="P_20"><b>20. Carr’s Vacuum Oven.</b>—A convenient drying oven has been
+devised in this laboratory by Carr.<a id="FNanchor_7" href="#Footnote_7" class="fnanchor">[7]</a>
+<span class="pagenum"><a id="Page_24"></a>[Pg 24]</span>
+It is made of a large tube, preferably of brass. The tube may be from
+six to nine inches in diameter and from twelve to fifteen inches long.
+One end is closed air-tight by a brass end-piece attached by a screw,
+or brazed. The other end is detachable and is made air-tight by ground
+surfaces and a soft washer. In the <a href="#FIG_10A">figure</a> this
+movable end-piece is shown attached by screw-nuts, but experience has
+shown that these are not necessary. On the upper longitudinal surfaces
+are apertures for the insertion of a vacuum gauge and for attachment to
+a vacuum apparatus.</p>
+
+<p>In the <a href="#FIG_10A">figure</a> the thermometer and aperture
+for introducing dry air or an inert gas are shown in the movable end
+disk, but they would be more conveniently placed in the fixed end. The
+oven is heated below by a gas burner, which conveniently should be as
+long as the oven. The heat is not allowed to strike the brass cylinder
+directly, but the latter is protected by a piece of asbestos paper.</p>
+
+<p>The temperature inside of the oven can be easily kept practically
+constant by means of a gas regulator, not shown in the figure, or
+by a little attention to the lamp. For a vacuum of twenty inches a
+temperature of about 80° should be maintained. When the vacuum is more
+complete a lower temperature can be employed. This apparatus is simple
+in construction, strong, cheap, and highly satisfactory in use.</p>
+
+<p><b>21. Drying in Hydrogen.</b>—In some of the processes of
+agricultural analysis it becomes important to dry the sample in
+hydrogen or other inert gas. This may be accomplished by introducing
+the dry gas desired into some form of the apparatus already described.
+The drying may either be accomplished in an atmosphere of hydrogen
+practically at rest or in a more limited quantity of the gas in motion.
+The latter method is to be preferred by reason of its greater rapidity.
+The analyst has at his command many forms of apparatus designed for the
+purpose mentioned above. It will be sufficient here to describe only
+two, devised particularly for agricultural purposes.</p>
+
+<p>The first one of these, designed by the author, was intended especially
+for drying the samples of fodders for analysis according to the methods
+of the Association of Agricultural
+Chemists.<a id="FNanchor_8" href="#Footnote_8" class="fnanchor">[8]</a></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_11" src="images/fig11.jpg" alt="" width="500" height="478" >
+    <p class="center spb1">Figure 11. Apparatus for Drying in a<br> Current of Hydrogen.</p>
+</div>
+
+<p>For the purpose of drying materials contained in flasks and tubes in a
+<span class="pagenum"><a id="Page_25"></a>[Pg 25]</span>
+current of hydrogen the apparatus shown in <a href="#FIG_11">Fig. 11</a> is
+used. This apparatus consists of a circular box, B, conveniently made of
+galvanized iron, having a movable cover, S, fitted for the introduction
+of steam into the interior of the apparatus. Condensed steam escapes at
+W. A stream of perfectly pure and dry hydrogen enters at H, passes up
+through the material to be dried, down through the bulb V, containing
+sulfuric acid, and follows the direction of the arrows through the rest
+of the apparatus. The stream of hydrogen is thus completely dried by
+passing through bulbs containing sulfuric acid, on the way from one
+<span class="pagenum"><a id="Page_26"></a>[Pg 26]</span>
+piece of the apparatus to the other. A, represents a flask such as is
+used, with the extraction apparatus described. The apparatus which we
+have used will hold eight tubes or flasks at a time, and thus a single
+stream of hydrogen is made to do duty eight times in drying eight
+separate samples. The great advantage of the apparatus is in the fact
+that the stream of hydrogen must pass over and through the substance
+to be dried. In order to prevent any sulfuric acid from being carried
+forward into the next tube the bulb K, above the sulfuric acid, may be
+filled with solid pieces of soda or potash.</p>
+
+<p>This apparatus has been in use for a long time and no accidents from
+sulfuric acid being carried forward have occurred, and there is no
+danger, provided the stream of hydrogen is kept running at a slow
+rate. If, however, by any accident the stream of hydrogen should be
+admitted with great rapidity, particles of the sulfuric acid might be
+carried forward and spoil the next sample. To avoid any such accident
+as this the proposal to introduce the potash bulb has been made. The
+apparatus works with perfect satisfaction, and it is believed that when
+properly adjusted check weighings can be made by weighing the bulbs,
+showing their increase in weight, which will give the volatile matter,
+and weighing the flasks or tubes, which will show the loss of weight.
+The only chance for error in weighing the bulbs is that some of the
+volatile matter may be material which is not dissolved in sulfuric
+acid, and is thus carried on and out of the apparatus. The blackening
+of the sulfuric acid in the bulbs, in the drying of all forms of
+organic matter, shows that the loss in weight of such bodies is not
+due to water alone, but also to organic volatile substances, which are
+capable of being decomposed by the sulfuric acid, thus blackening it.</p>
+
+<p><b>22. Caldwell’s Hydrogen Drying-Bath.</b>—An excellent device for
+drying in hydrogen has been described by Caldwell.<a id="FNanchor_9" href="#Footnote_9" class="fnanchor">[9]</a>
+A vessel of copper or other suitable material serves to hold the tubes
+containing the samples to be dried. It should be about twenty-four
+centimeters long, fifteen high, and eight wide. This vessel is
+contained in another made of the same material and of the dimensions
+shown in the <a href="#FIG_12">figure</a>. On one side the edge of this
+<span class="pagenum"><a id="Page_27"></a>[Pg 27]</span>
+containing vessel may not be more than one centimeter high and the bath
+should rest against it. The other side is made higher to form a support
+for the drying tubes as indicated.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_12" src="images/fig12.jpg" alt="" width="400" height="441" >
+    <p class="center spb1">Figure 12. Caldwell’s Hydrogen Drying Apparatus.</p>
+</div>
+
+<p>The tube containing the substance <i>a d</i> is made of glass and may
+be closed by the ground stoppers <i>c b</i> or the tube stoppers <i>e
+f</i>. At <i>a</i> it carries a perforated platinum disk for holding
+the filtering felt. The tube should be about thirteen centimeters long
+and have an internal diameter of about twenty millimeters. With its
+stoppers it should weigh only a little over thirty grams. The asbestos
+felt should not be thick enough to prevent the free passage of gas.
+Passing diagonally through the bath are metal tubes, preferably made of
+copper, and of such a size as just to receive the glass drying tubes.
+If these be a little loose they should be made tight by wrapping them
+with a narrow coil of paper at either end of the tubular receptacle.
+The entrance of cold air between the glass tube and its metal holder is
+thus prevented, and the glass tube is held firmly in position. The glass
+<span class="pagenum"><a id="Page_28"></a>[Pg 28]</span>
+tube should be weighed with its two solid stoppers. Afterwards the
+sample, about two grams, is placed on the asbestos felt and the
+stoppers replaced and the whole reweighed. The exact weight of the
+sample is thus obtained. The solid stoppers are then removed and the
+tube stoppers inserted. The lower end of the tube is then connected
+with the supply of dry hydrogen. The upper tube stopper is connected
+by a rubber tube with a small bottle containing sulfuric acid through
+which the escaping hydrogen is made to bubble. A double purpose is thus
+secured; moisture is kept from entering the drying tube and the rate
+at which the hydrogen is passing is easily noted. After the drying is
+completed the solid stoppers are again inserted, the tube cooled in a
+desiccator and weighed. The loss of weight is entered as water. The
+tube containing the sample can afterwards be put into an extractor and
+treated with ether or petroleum in the manner hereafter described. This
+apparatus requires more hydrogen than the one previously described,
+but it is rather simple in construction, is easily controlled, and has
+given satisfactory results.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_13" src="images/fig13.jpg" alt="" width="400" height="204" >
+    <p class="center spb1">Figure 13. Liebig’s Ente.</p>
+</div>
+
+<p><b>23. Drying in Liebig’s Tubes.</b>—In drying samples, especially of
+fodders, the method practiced at the Halle Station is to place them
+in drying tubes, the form of which is shown in <a href="#FIG_13">Fig. 13</a>.
+A stream of illuminating gas, previously dried by passing over sulfuric acid and
+calcium chlorid, is directed through the tubes.<a id="FNanchor_10" href="#Footnote_10" class="fnanchor">[10]</a>
+Many of these tubes can be used at once, arranged as shown in <a href="#FIG_14">Fig. 14</a>.
+When the air is all driven out the stream of gas can be ignited so as
+to regulate the flow properly by the size of the flame. The tubes are
+held in drying ovens, as shown in the <a href="#FIG_14">figure</a>, the temperature
+of which should be kept at 105°-107°. The drying should be continued for eight
+or ten hours. At the end of this time the gas in the tube is to be
+expelled by a stream of dry air and the tubes cooled in a desiccator
+and weighed. There are few advantages in this method not possessed by
+the processes already described. The samples, moreover, are not left
+in a condition for further examination, either by incineration or extraction.
+<span class="pagenum"><a id="Page_29"></a>[Pg 29]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_14" src="images/fig14.jpg" alt="" width="600" height="372" >
+    <p class="center spb1">Figure 14. Drying Apparatus used at the Halle Station.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_30"></a>[Pg 30]</span>
+<b>24. Wrampelmayer’s Drying Oven.</b>—The apparatus used at the
+Wageningen Station, in Holland, for drying agricultural samples,
+was devised by Wrampelmayer and is shown in <a href="#FIG_15">Fig. 15</a>.
+The oven is so constructed as to permit of drying in a stream of inert gas.
+Illuminating gas is let into the drying space of the oven through the
+tube A B. At B the entering gas is heated by the same lamp which boils
+the liquid in the water space of the apparatus. The hot gas is dried in
+the calcium chlorid tube c and then passes into the oven at D. At E it
+leaves the apparatus and is thence conducted to the lamp F, used for
+heating the bath. The lamp should be closed by a wire gauze diaphragm
+to prevent any possible explosion by reason of any admixture with the
+air in the oven. The condensation of the aqueous vapors is effected by
+means of the condenser G. In the drying space is a small shelf holder,
+which, by means of the hook H, can be removed from the apparatus. The
+drying space is closed from the upper part of the apparatus, which
+contains no water by the cover J, resting on a support K. This rim is
+covered with a rubber gasket L, by means of which the cover J can be
+fastened with a bayonet latch air-tight. This fastening is shown at N.
+Being closed in this way the part of the cylindrical oven above the
+cover may be left entirely open. Instead of the rather elaborate method
+of closing the bath, some simple and equally effective device might be
+used. The cover J is best made with double metallic walls enclosing an
+asbestos packing.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_15" src="images/fig15.jpg" alt="" width="400" height="545" >
+    <p class="center spb1">Figure 15. Wrampelmayer’s Oven.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_31"></a>[Pg 31]</span>
+It is evident that this oven could be used with an atmosphere of carbon
+dioxid or of air, provided the gas for heating were derived from a
+separate source and the tube between E and F broken. In a drying oven
+designed by the author, the movable top is made with double walls and
+the space between is joined to the steam chamber by means of a flexible
+metallic tube, thus entirely surrounding the drying space with steam.</p>
+
+<p><b>25. The Ulsch Drying Oven.</b>—A convenient drying oven is
+described by Ulsch which varies from the ordinary form of a
+water-jacketed drying apparatus in having a series of drying tubes
+inserted in the water-steam space.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_16" src="images/fig16.jpg" alt="" width="500" height="438" >
+    <p class="center spb1">Figure 16. Ulsch Drying Oven.</p>
+</div>
+
+<p>The arrangement of the oven is shown in the accompanying <a href="#FIG_16">figure</a>.
+The water space is filled only to about one-third of its height. When the
+heat is applied the cock <i>c</i> is left open until the steam has
+<span class="pagenum"><a id="Page_32"></a>[Pg 32]</span>
+driven out all the air. It is then closed and the temperature of the
+bath is then regulated by the manometer <i>e</i>, connected with the
+bath by <i>d</i>. The bottom of the manometer cylinder contains enough
+mercury to always keep sealed the end of the manometer tube. The rest
+of the space is filled with water. At the top the manometer tube is
+expanded into a small bulb which serves as a gas regulator, as shown
+in the <a href="#FIG_16">figure</a>. The gas is admitted also by a
+small hole above the mercury in the bulb, so that when the end of
+the gas inlet tube is sealed enough gas still passes through to keep
+the lamp burning. With a mercury pressure of thirty centimeters the
+temperature of the bath will be about 105°. The walls of the bath
+should be made strong enough to bear the pressure corresponding to this
+degree. The drying can be accomplished either in the cubical drying
+box <i>a</i> or in the drying tubes made of thin copper and disposed
+as shown in the <a href="#FIG_16">figure</a>. The natural draft is
+shown by the arrows. The substance is held in boats placed in the tube
+as indicated. The air in traversing the tube is brought almost to
+the temperature of the water-steam space in which the tube lies. The
+natural current of hot air can easily be replaced by a stream of dry
+illuminating or other inert gas.</p>
+
+<p id="P_26"><b>26. Drying Viscous Liquids.</b>—In the case of cane juices, milk,
+and similar substances, the paper coil method may be used.<a id="FNanchor_11" href="#Footnote_11" class="fnanchor">[11]</a>
+The manipulation is conducted as follows: A strip of filtering paper from
+five to eight centimeters wide and forty centimeters in length, is
+rolled into a loose coil and dried at the temperature of boiling water
+for two hours, placed in a dry glass-stoppered weighing tube, cooled
+in a desiccator and weighed. The stoppered weighing tube prevents the
+absorption of hygroscopic moisture. About three cubic centimeters of
+the viscous or semi-viscous liquid are placed in a flat dish covered
+by a plate of thin glass and weighed. The coil is then placed on end
+in the dish, and the greater part of the liquid is at once absorbed.
+The proportions between the coil and the amount of liquid should be
+such that the coil will not be saturated more than two-thirds of its
+length. It is then removed and placed dry end down in a steam-bath
+and dried two hours. The dish, covered by the same plate of glass, is
+again weighed, the loss in weight representing the quantity of liquid
+<span class="pagenum"><a id="Page_33"></a>[Pg 33]</span>
+absorbed by the coil. After drying for the time specified the coil
+is again placed in the hot weighing tube, cooled and its weight
+ascertained. The increase represents the solid matter in the sample
+taken. This method has been somewhat modified by Josse, who directs
+that it be conducted as follows:<a id="FNanchor_12" href="#Footnote_12" class="fnanchor">[12]</a>
+Filter-paper is cut into strips from one to two centimeters wide and
+three meters long. The strips are crimped so they will not lie too
+closely together and then wrapped into coils. These coils can absorb
+about ten cubic centimeters of liquid. One of them is placed in a flat
+dish about two centimeters high and seven in diameter, and dried as
+described, covered, cooled and weighed. There are next placed in the
+dish and weighed one or two grams of the massecuite, molasses, etc.,
+which are to be dried and the dish again weighed and the total weight
+of the matter added, determined by deducting the weight of the dish and
+cover. About eight cubic centimeters of water are added, the material
+dissolved with gentle warming, the coil placed in the dish, and the
+whole dried for two hours. The cover is then replaced and the whole
+cooled in a desiccator and weighed. The increase in weight represents
+the dry matter in the sample taken.</p>
+
+<p>The above method of solution of a viscous sample in order to divide
+it evenly for desiccation is based on the principle of the method
+first proposed by the author and Broadbent for drying honeys and other
+viscous liquids.<a id="FNanchor_13" href="#Footnote_13" class="fnanchor">[13]</a>
+In this process the sample of honey, molasses, or other viscous liquid
+is weighed in a flat dish, dissolved in eighty per cent alcohol, and
+then a weighed quantity of pure dry sand added, sufficient to fill
+the dish three-quarters full. The alcoholic solution of the viscous
+liquid is evenly distributed throughout the mass of sand by capillary
+attraction, and thus easily and rapidly dried when placed on the bath.</p>
+
+<p>Pumice stone, on account of its great porosity, is also an excellent
+medium for the distribution of a viscous liquid in aiding the process
+of desiccation. The method has been worked out in great detail in
+this laboratory by Carr and Sanborn,<a id="FNanchor_14" href="#Footnote_14" class="fnanchor">[14]</a>
+and most excellent results obtained. Round aluminum dishes two
+centimeters high and from eight to ten centimeters in diameter are
+conveniently used for this process. The pumice stone is dried and
+broken into fragments the size of a pea before use.
+<span class="pagenum"><a id="Page_34"></a>[Pg 34]</span></p>
+
+<p><b>27. General Principles of Drying Samples.</b>—It would be a
+needless waste of space to go into further details of devices for
+desiccation. A sufficient number has been given to fully illustrate all
+the principles involved. In general, it may be said that drying in the
+open air at a temperature not exceeding that of boiling water can be
+safely practiced with the majority of samples. For instance, we have
+found practically no change in this laboratory in the composition of
+cereals dried in the air and in an inert gas. The desiccation should
+in all cases be accomplished as speedily as possible. To this end the
+atmosphere in contact with the sample should be dry and kept in motion.
+An oven surrounded by boiling water and steam is to be preferred to
+one heated by air. Constancy of temperature is quite as important as
+its degree and this steadiness is most easily secured by steam at
+atmospheric pressure. Where higher temperatures than 100° are desired
+the steam must be under pressure, or the boiling-point of the water may
+be raised by adding salt or other soluble matters. A bath of paraffin
+or calcium chlorid may also be used or a sand or air-bath may be
+employed. The analyst must not forget, however, that inorganic matters
+are prone to change at temperatures above 100°, even in an inert
+atmosphere, and higher temperatures must be used with extreme caution.</p>
+
+<p>Drying in partial vacuum and in a slowly changing atmosphere may
+be practiced with all bodies and must be employed with some. The
+simple form of apparatus already described will be found useful for
+this purpose. At a vacuum of twenty inches or more, even unstable
+organic agricultural products are in little danger of oxidation. In
+the introduction of a dry gas, therefore, air will be found as a
+rule entirely satisfactory. In the smaller form of vacuum apparatus
+described, however, there is no objection to the employment of hydrogen
+or of carbon dioxid. The gas entering the apparatus should be dried by
+passing over calcium chlorid or by bubbling through sulfuric acid. In
+this laboratory the vacuum is provided by an air-pump connected with a
+large exhaust cylinder. This cylinder is connected by a system of pipes
+to all the working desks. The chief objection to this system is the
+<span class="pagenum"><a id="Page_35"></a>[Pg 35]</span>
+unsteadiness of the pressure. When only a few are using the vacuum
+apparatus for filtering or other purposes the vacuum will stand at
+about twenty inches. When no one is using it the vacuum will rise to
+twenty-eight or twenty-nine inches. At other times, when in general
+use, it may fall to fifteen inches. Where a constant vacuum is desired
+for drying, therefore, it is advisable to connect the apparatus with a
+special aspirator which will give a pressure practically constant.</p>
+
+<p>The dishes containing the sample should be low and flat, exposing as
+large a surface as possible. For viscous liquids it will be found
+advisable to previously fill the dishes with pumice stone or other
+inert absorbent material to increase the surface exposed.</p>
+
+<p>The special methods of drying milk, sirup, honeys, and like bodies,
+will be described in the paragraphs devoted to these substances.</p>
+
+<p>In drying agricultural products, not only water but all other matters
+volatile at the temperature employed are expelled. It is only necessary
+to conduct the products of volatilization through sulfuric acid to
+demonstrate the fact that organic bodies are given off. In the case
+mentioned the sulfuric acid will be speedily changed to a brown and
+even black color by these bodies. It is incontestable, however, that
+in most cases the essential oils and other volatile matters thus
+escaping are not large in quantity and could not appreciably affect
+the percentage composition of the sample. In such cases the whole of
+the loss on drying is entered in the note book as water. There are
+evidently many products, however, where a considerable percentage of
+the volatile products is not water. The percentage of essential oils,
+which have a lower boiling-point than water, can be determined in a
+separate sample and this deducted from the total loss on drying will
+give the water.</p>
+
+<p>Simple as it seems, the determination of water in agricultural products
+often presents peculiar difficulties and taxes to the utmost the
+patience and skill of the analyst. Having set forth the substantial
+principles of the process and indicated its more important methods,
+there is left for the worker in the laboratory the choice of processes
+<span class="pagenum"><a id="Page_36"></a>[Pg 36]</span>
+already described, or, in special cases, the device of new ones and
+adaption of old ones to meet the requirements of necessity.</p>
+
+<h3>INCINERATION.</h3>
+
+<p id="P_28"><b>28. Determination of Ash.</b>—The principle to be kept in view in
+the preparation of the ash of agricultural products is to conduct the
+incineration at as low a temperature as possible to secure a complete
+combustion. The danger of too high a temperature is two-fold. In the
+first place some of the mineral constituents constantly present in the
+ash, notably, some of the salts of potassium and sodium are volatile
+at high temperatures and thus escape detection. In the second place,
+some parts of the ash are rather easily fusible and in the melted state
+occlude particles of unburned organic matter, and thus protect them
+from complete oxidation. Both of these dangers are avoided, and an ash
+practically free of carbon obtained, by conducting the combustion at
+the lowest possible temperature capable of securing the oxidation of
+the carbonaceous matter.</p>
+
+<p><b>29. Products Of Combustion.</b>—The most important product of
+combustion, from the present point of view, is the mineral residue
+obtained. The organic matter of the sample undergoes decomposition
+in various ways, depending chiefly on its nature. Complex volatile
+compounds are formed first largely of an acid nature. The residual
+carbon is oxidized to carbon dioxid and the hydrogen to water. The
+relative proportions of these bodies formed, in any given case, depend
+on the conditions of combustion. With a low temperature and a slow
+supply of oxygen, the proportion of volatile organic compounds is
+increased. At a high temperature, and in a surplus of oxygen, the
+proportions of water and carbon dioxid are greater. At the present
+time, however, our attention is to be directed exclusively to the
+mineral residue; the organic products of combustion belonging to the
+domain of organic chemistry. As has already been intimated, the ash of
+agricultural samples consists of the mineral matters derived from the
+tissues, together with any accidental mineral impurities which may be
+present, some unburned carbon, and the sulfur, phosphorus, chlorin,
+nitrogen, etc., existing previously in combination with the mineral
+bases. The organic sulfur and phosphorus may also undergo complete or
+<span class="pagenum"><a id="Page_37"></a>[Pg 37]</span>
+partial oxidation during incineration and be found in the ash. Unless
+special precautions be taken, however, a portion of the organic
+sulfur and phosphorus may escape as volatile compounds during the
+combustion.<a id="FNanchor_15" href="#Footnote_15" class="fnanchor">[15]</a>
+The organic nitrogen is probably completely lost, at most, only traces
+of it being oxidized during the combustion in such a way as to combine
+with a mineral base. The rare mineral elements that are taken up by
+plants will also be found in the ash. Here the analyst would look for
+copper, boron, zinc, manganese, and the other elements which, when
+existing in the soil, are apt to be found in the tissues of the plants,
+not, perhaps, as organic or essential compounds, but as concomitants
+of the other mineral foods absorbed by growing vegetation. This fact
+is often of importance in toxicological and hygienic examinations of
+foods. For instance, traces of copper or of boron in the ash of a
+prescribed food would not be evidence of the use of copper or borax
+salts as preservatives unless it could be shown that the soil on which
+the food in question was grown was free of these bodies.</p>
+
+<p>This fact manifestly applies only to those cases where mere traces
+of these rare bodies are in question. The presence of considerable
+quantities of them, enough to be inimical to health, could only be
+attributed to artificial means.</p>
+
+<p><b>30. Purpose and Conduct of Incineration.</b>—In burning a sample
+of an agricultural product the analyst may desire to secure either a
+large sample of ash for analytical purposes as already described or to
+determine the actual percentage of ash. The first purpose is secured
+in many ways. In the preparation of ash for manurial purposes, for
+instance, little care is exercised either to prevent volatilization of
+mineral matters or to avoid the occurrence of a considerable quantity
+of carbon in the sample. With this operation we have, at present,
+nothing whatever to do. In preparing a sample of ash for chemical
+analysis it is important, where a sufficient quantity of the sample can
+be obtained, to use as large a quantity of it as convenient. While it
+is true that very good results may be secured on very small samples,
+it is always advisable to have a good supply of the material at hand.
+Since the materials burned have only from one to three per cent of ash,
+a kilogram of them will supply only from ten to thirty grams. To supply
+<span class="pagenum"><a id="Page_38"></a>[Pg 38]</span>
+all needful quantities of material and replace the losses due to
+accident, whenever possible at least twenty grams of the ash should
+be prepared. The combustion can be carried on in platinum dishes with
+all bodies free of metallic oxids capable of injuring the platinum.
+Otherwise porcelain or clay dishes may be employed. As a rule the
+combustion is best conducted in a muffle at a low red heat. With
+substances very rich in fusible ash, as for instance the cereals, it is
+advisable to first char them, extract the greater part of the ash with
+water, and afterwards burn the residual carbon. The aqueous extract can
+then be added to the residue of combustion and evaporated to dryness at
+the temperature of boiling water. During the combustion the contents
+of the dish should not be disturbed until the carbon is as completely
+burned out as possible. The naturally porous condition in which the
+mass is left during the burning is best suited to the entire oxidation
+of the carbon. At the end however, it may become necessary to bring
+the superficial particles of unburned carbon into direct contact with
+the bottom of the dish by stirring its contents. In most instances
+very good results may be obtained by burning the ash in an open dish
+without the aid of a muffle. In this case a lamp should be used with
+diffuse flame covering as evenly as possible the bottom of the dish and
+thus securing a uniform temperature. The carbon, when once in active
+combustion, will as a rule be consumed, and an ash reasonably pure be
+obtained.</p>
+
+<p>The second purpose held in view by the analyst is to determine the
+actual content of ash in a sample. For this purpose only a small
+quantity of the material should be used, generally from two to ten
+grams. The combustion should be conducted in flat-bottomed, shallow
+dishes, and at a low temperature. In many cases the residue, after
+determining the moisture, can be at once subjected to incineration,
+and thus an important saving of time be secured. A muffle, with gentle
+draft, will be found most useful for securing a white ash. The term,
+white ash, is sometimes a deceptive one. In samples containing iron or
+manganese, the ash may be practically free of carbon and yet be highly
+colored. The point at which the combustion is to be considered as
+<span class="pagenum"><a id="Page_39"></a>[Pg 39]</span>
+finished therefore should be at the time the carbon has disappeared
+rather than when no coloration exists. In general the methods of
+incineration are the same for all substances, but some cases may arise
+in which special processes must be employed. Some analysts prefer to
+saturate the substance before incineration with sulfuric acid, securing
+thus a sulfated ash. This is practiced especially with molasses. In
+such cases the ash obtained is free of carbon dioxid and roughly the
+difference in weight is compensated for by deducting one-tenth of
+the weight of the ash when comparison is to be made with ordinary
+carbonated ash. Naturally this process could not be used when sulfuric
+acid is to be determined in the product.</p>
+
+<div class="figleft smcap">
+    <img id="FIG_17" src="images/fig17.jpg" alt="" width="200" height="329" >
+    <p class="center spb1">Figure 17. Courtoune Muffle.</p>
+</div>
+
+<p><b>31. German Ash Method.</b>—The method pursued at the Halle Station
+for securing the percentage of ash in a sample is as follows:<a id="FNanchor_16" href="#Footnote_16" class="fnanchor">[16]</a>
+Five grams of the air-dried sample are incinerated in a platinum dish and
+the ash ignited until it has assumed a white, or at least a bright
+gray tint. As soon as combustible gases are emitted at the beginning
+of the incineration they are ignited and allowed to burn as long as
+possible. It is advisable to hasten the oxidation by stirring the mass
+with a piece of platinum wire. If the ash should become agglomerated,
+as sometimes happens with rich food materials, it must be separated by
+attrition. The ash, when cooled on a desiccator, is to be weighed. When
+great exactness is required, it is advised, as set forth in a former
+<span class="pagenum"><a id="Page_40"></a>[Pg 40]</span>
+paragraph, to first carbonize the mass and then extract the soluble
+ash with hot water before completing the oxidation. When the latter is
+complete and the dish cooled the aqueous extract is added, evaporated
+to dryness and the incineration completed.</p>
+
+<p><b>32. Courtonne’s Muffle.</b>—The ordinary arrangement of a muffle,
+as in assaying, may be conveniently used in incineration. A special
+muffle arrangement has been prepared by Courtonne which not only
+permits of the burning of a large number of samples at once, but also
+effects a considerable saving in gas. The muffle as shown in <a href="#FIG_17">Fig. 17</a>,
+is made in two stages, and the floor projects in front of the furnace,
+forming a convenient hearth. The incineration is commenced on the upper
+stage, where the temperature is low, and finished on the lower one at a
+higher heat. The furnace is so arranged as to permit the flame of the
+burning gas to entirely surround the muffle. The draft and temperature
+within the muffle are controlled by the fire-clay door shown resting on
+the table.</p>
+
+<h3>TREATMENT WITH SOLVENTS.</h3>
+
+<p id="P_33"><b>33. Object Of Treatment.</b>—The next step, in the analytical
+work, after sampling, drying, and incinerating, is the treatment of
+the sample with solvents. The object of this work is to separate
+the material under examination into distinct classes of bodies
+distinguished from each other by their solubilities. It is not the
+purpose of this section to describe the various bodies which may
+be separated in this way, especially from vegetable products. For
+this description the reader may consult the standard works on plant
+analysis.<a id="FNanchor_17" href="#Footnote_17" class="fnanchor">[17]</a></p>
+
+<p>The chief object of a strictly agricultural examination of a field or
+garden product is to determine its food value. This purpose can be
+accomplished without entering into a minute separation of nearly allied
+bodies. For example, in the case of carbohydrates it will be sufficient
+as a rule, to separate them into four classes. In the first class will
+be found those soluble in water as the ordinary sugars. In the second
+group will be found those which, while not easily soluble in water, are
+readily rendered so by treatment with certain ferments or by hydrolysis
+with an acid. The starches are types of this class. In the third place
+<span class="pagenum"><a id="Page_41"></a>[Pg 41]</span>
+are found those bodies which resist the usual processes of hydrolysis
+either with an acid or alkali, and therefore remain in the residue as
+fiber. Cellulose is a type of these bodies. In the fourth class are
+included those bodies which on hydrolysis with an acid yield furfurol
+on distillation, and therefore belong to the type containing five atoms
+of carbon or some multiple thereof in their molecule. For ordinary
+agricultural purpose the separation is not even as complete as is
+represented above.</p>
+
+<p>What is true of the carbohydrates applies equally well to the fats and
+to other groups. Especially in the analysis of cereals and of cattle
+foods, the treatment with solvents is confined to the use in successive
+order of ether or petroleum, alcohol, dilute acids, and alkalies, the
+latter at a boiling temperature. The general method of treatment with
+these solvents will be the subject of the following paragraphs.</p>
+
+<p><b>34. Extraction of the Fats and Oils.</b>—Two solvents are in
+general use for the extraction of fats and oils; <i>viz.</i>, ethylic
+ether and a light petroleum. The former is the more common reagent.
+Before use it should be made as pure as possible by washing first
+with water, afterwards removing the water by lime or calcium chlorid,
+and then completing the drying by treatment with metallic sodium.
+The petroleum spirit used should be purified by several fractional
+distillations until it has nearly a constant boiling-point of from 45°
+to 50°. The detailed methods of preparing these reagents will be given
+in another place. For rigid scientific determinations the petroleum
+is to be preferred to the ether. It is equally as good a solvent
+for fats and oils and is almost inert in respect to other vegetable
+constituents. Ether, on the other hand, dissolves chlorophyll and its
+partial oxidation products, resins, alkaloids and the like. The extract
+obtained by ether is therefore less likely to be a pure fat than that
+secured by petroleum. For purposes of comparison, however, the ether
+should be employed, inasmuch as it has been used almost exclusively in
+analytical operations in the past.</p>
+
+<p><b>35. Methods Of Extraction.</b>—The simplest method for
+accomplishing the extraction of fat from a sample consists in treating
+<span class="pagenum"><a id="Page_42"></a>[Pg 42]</span>
+it with successive portions of the solvent in an open dish or a closed
+flask. This process is actually employed in some analytical operations,
+as, for instance, in the determination of fat in milk. Experience has
+shown, however, that a portion of the substance soluble, for instance,
+in ether, passes very slowly into solution, so that a treatment such as
+that just described would have to be long continued to secure maximum
+results. The quantity of solvent required would thus become very large
+and in the case of ether would entail a great expense. For the greater
+number of analytical operations, therefore, some device is employed for
+using the same solvent continually. The methods of extraction therefore
+fall into two general classes; <i>viz.</i>, extraction by digestion
+and extraction by percolation. This classification holds good also for
+other solvents besides ether and petroleum. In general, the principles
+and practice of extraction described for ether may serve equally well
+for alcohol, acetone and other common solvents.</p>
+
+<p><b>36. Extraction by Digestion.</b>—In the use of ether or petroleum
+the sample is covered with an excess of the solvent and allowed to
+remain for some time in contact therewith. The soluble portions of the
+sample diffuse into the reagent. The speed of diffusion is promoted
+by stirring the mixtures. The operation may be conducted in an open
+dish or a flask. Inasmuch as the residue is, as a rule, to be dried
+and weighed, an open dish is to be preferred. To avoid loss of reagent
+and to prevent filling a working room with very dangerous gases, the
+temperature of digestion should be kept below the boiling-point of the
+solvent. The greater part of the soluble matter will be extracted with
+three or four successive applications of the reagent, but, as intimated
+above, the last portions of the soluble material are extracted with
+difficulty by this process. In pouring off the solvent care must be
+exercised to avoid loss of particles of the sample suspended therein.
+To this end it is best to pour the solvent through a filter. For the
+extraction of large quantities of material for the purpose of securing
+the extract for future examination, or simply to remove it, the
+digestion process is usually employed. This excess of solvent required
+is easily recovered by subsequent distillation and used again. The
+method is rarely used for the quantitive estimation of the extract, the
+<span class="pagenum"><a id="Page_43"></a>[Pg 43]</span>
+process of continuous percolation being more convenient and more exact.</p>
+
+<p><b>37. Extraction by Percolation.</b>—In this method the solvent
+employed is poured on the top of the material to be extracted and
+allowed to pass through it usually by gravitation alone, sometimes with
+the help of a filter-pump. The principle of the process is essentially
+that of washing precipitates.</p>
+
+<p>Two distinct forms of apparatus are in use for this process. In
+the first kind the solvent is poured over the material and after
+percolation is secured by distillation in another apparatus. In the
+second kind the solvent is secured after percolation in a flask where
+it is at once subjected to distillation. The vapors of the solvent
+are conducted by appropriate means to a condenser placed above the
+sample. After condensation the solvent is returned to the upper part of
+the sample. The percolation thus becomes continuous and a very small
+quantity of the solvent may thus be made to extract a comparatively
+large amount of material. This process is particularly applicable
+to the quantitive determination of the extract. After distillation
+and drying the latter may be weighed in the flask in which it was
+received or the sample may be dried and weighed in the vessel in which
+it is held both before and after extraction. One great advantage of
+the continuous extraction method lies in the fact that when it is
+once properly started it goes on without further attention from the
+analyst save an occasional examination of the flow of water through
+the condenser and of the rate of the distillation. For this reason the
+process may be continued for many hours without any notable loss of
+time. The vapor of the solvent in passing to the condenser may pass
+through a tube out of contact with the material to be extracted or it
+may pass directly around the tube holding the sample. In the former
+case the advantage is secured of conducting the extraction at a higher
+temperature, but there is danger of boiling the solvent in contact with
+the material and thus permitting the loss of a portion of the sample.</p>
+
+<p><b>38. Apparatus Used for Extractions.</b>—For extraction by
+digestion, as has already been said, an open dish may be used. When
+large quantities of material are under treatment, heavy flasks, holding
+<span class="pagenum"><a id="Page_44"></a>[Pg 44]</span>
+from five to ten liters, will be found convenient. In these cases a
+condenser can be attached to the flask and the extraction conducted
+at the boiling temperature of the solvent. During the process of
+extraction it is advisable to shake the flask frequently. By proceeding
+in this way the greater part of the solvent matter will be removed
+after three or four successive treatments.</p>
+
+<p>In extraction by percolation various forms of apparatus are employed.
+The ordinary percolators of the manufacturing pharmacist may be used
+for the larger operations, while the more elaborate forms of continuous
+extractors will be found most convenient for quantitive work. In each
+case the analyst must choose that process and form of apparatus best
+suited to the purpose in view. In the next paragraphs will be described
+some of the more common forms of apparatus in use.</p>
+
+<p id="P_39"><b>39. Knorr’s Extraction Apparatus.</b>—The apparatus which has been
+chiefly used in this laboratory for the past few years is shown in
+the accompanying <a href="#FIG_18">figure</a>.<a id="FNanchor_18" href="#Footnote_18" class="fnanchor">[18]</a>
+The principle of the construction of the apparatus lies in the complete
+suppression of stoppers and in sealing the only joint of the device
+with mercury.</p>
+
+<p>The construction and operation of the apparatus will be understood by a
+brief description of its parts.</p>
+
+<p>A is the flask containing the solvent, W a steam bath made by cutting
+off the top of a bottle, inverting it and conducting the steam into one
+of the tubes shown in the stopper while the condensed water runs out of
+the other. The top of the bath is covered with a number of concentric
+copper rings, so that the opening may be made of any desirable size. B
+represents the condenser, which is a long glass tube on which a number
+of bulbs has been blown, and which is attached to the hood for holding
+the material to be extracted, as represented at Bʹ, making a solid
+glass union. Before joining the tube at Bʹ the rubber stopper which is
+to hold it into the outside condenser of B is slipped on, or the rubber
+stopper may be cut into its center and slipped over the tube after the
+union is made. In case alcohol is to be used for the solvent, requiring
+a higher temperature, the flask holding the solvent is placed entirely
+within the steam-bath, as represented at Aʹ.
+<span class="pagenum"><a id="Page_45"></a>[Pg 45]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_18" src="images/fig18.jpg" alt="" width="400" height="670" >
+    <p class="center spb1">Figure 18. Knorr’s Extraction Apparatus.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_46"></a>[Pg 46]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_19" src="images/fig19.jpg" alt="" width="600" height="316" >
+    <p class="center spb1">Figure 19. Extraction Flask.</p>
+</div>
+
+<div class="figcontainer smcap">
+  <div class="figsub">
+   <img id="FIG_20" src="images/fig20.jpg" alt="" width="210" height="386" >
+   <p class="center">Figure 20.<br> Extraction Tube.</p>
+  </div>
+  <div class="figsub">
+   <img  id="FIG_21" src="images/fig21.jpg" alt="" width="200" height="383" >
+   <p class="center">Figure 21.<br> Extraction Siphon Tube.</p>
+   </div>
+</div>
+
+<p>A more detailed description of the different parts of the apparatus
+can be seen by consulting Figs. <a href="#FIG_19">19</a>, <a href="#FIG_20">20</a>,
+and <a href="#FIG_21">21</a>. In A, <a href="#FIG_19">Fig. 19</a>, is
+represented a section of the flask which holds the solvent, showing how
+the sides of the hood containing the matters to be extracted pass over
+<span class="pagenum"><a id="Page_47"></a>[Pg 47]</span>
+the neck of the flask, and showing at S a small siphon inserted in the
+space between the neck of the flask and the walls of the hood for the
+purpose of removing any solvent that may accumulate in this space.
+A view of the flask itself is shown at Aʹ. It is made by taking an
+ordinary flask, softening it about the neck and pressing the neck in
+so as to form a cup, as indicated at Aʹ, to hold the mercury which
+seals the union of the flask with the condenser. The flask is held in
+position by passing a rubber band below it, which is attached to two
+glass nipples, <i>b</i>, blown onto the containing vessel, as shown in
+<a href="#FIG_18">Fig. 18</a>. The material to be extracted may be contained in an ordinary
+tube, as shown in <a href="#FIG_20">Fig. 20</a>, which may be made from a test tube drawn
+out, as indicated in the figure, having a perforated platinum disk
+sealed in at D. The containing tube rests upon the edges of the flask
+containing the solvent by means of nipples shown at <i>t</i>. If a
+siphon tube is to be used, one of the most convenient forms is shown in
+<a href="#FIG_21">Fig. 21</a>, in which the siphon lies entirely within
+the extracting tube, thus being protected from breakage. By means of
+this apparatus the extractions can be carried on with a very small
+quantity of solvent, there being scarcely any leakage, even with the
+most volatile solvents, such as ether and petroleum. The apparatus is
+always ready for use, no corks are to be extracted, and no ground glass
+joints to be fitted.</p>
+
+<p id="P_40"><b>40. Soxhlet’s Extraction Apparatus.</b>—A form of continuous
+extraction apparatus has been proposed by Soxhlet which permits the
+passage of the vapors of the solvent into the condenser by a separate
+tube and the return of the condensed solvent after having stood in
+contact with the sample, to the evaporating flask by a siphon. The
+advantage of this process lies in freeing the sample entirely from the
+rise of temperature due to contact with the vapors of the solvent, and
+in the second place in the complete saturation of the sample with the
+solvent before siphoning. The sample is conveniently held in a cylinder
+of extracted filter-paper open above and closed below. This is placed
+in the large tube between the evaporating flask and the condenser. The
+sample should not fill the paper holder, and if disposed to float in
+the solvent, should be held down with a plug of asbestos fiber or of
+glass wool. The extract may be transferred, by dissolving in the
+<span class="pagenum"><a id="Page_48"></a>[Pg 48]</span>
+solvent, from the flask to a drying dish, or it may be dried and
+weighed in the flask where first received.</p>
+
+<div class="figleft smcap">
+    <img id="FIG_22" src="images/fig22.jpg" alt="" width="100" height="411" >
+    <p class="center spb1">Figure 22.<br> Soxhlet<br> Extraction<br> Apparatus.</p>
+</div>
+
+<p>There are many forms of apparatus of this kind, one of which is shown
+in <a href="#FIG_22">Fig. 22</a>, but a more extended description of
+them is not necessary. The disadvantages of this process as compared
+with Knorr’s, are quite apparent. The connections with the evaporating
+flask and condenser are made with cork stoppers, which must be
+previously thoroughly extracted with ether and alcohol. These corks
+soon become dry and hard and difficult to use. The joints are likely
+to leak, and grave dangers of explosion arise from the vapors of the
+solvents escaping into the working room. Moreover, it is an advantage
+to have the sample warmed by the vapors of the solvent during the
+progress of the extraction, provided the liquid in direct contact with
+the sample does not boil with sufficient vigor to cause loss.</p>
+
+<p>The use of extraction apparatus with ground glass joints is also
+unsatisfactory. By reason of unequal expansion and contraction these
+joints often are not tight. They are also liable to break and thus
+bring danger and loss of time.</p>
+
+<p><b>41. Compact Extraction Apparatus.</b>—In order to bring the
+extraction apparatus into a more compact form, the following described
+device has been successfully used in this laboratory.<a id="FNanchor_19" href="#Footnote_19" class="fnanchor">[19]</a>
+The condenser employed is made of metal and is found entirely within
+the tube holding the solvent.</p>
+
+<p>This form of condenser is shown in <a href="#FIG_23">Fig. 23</a>, in which
+the tube E serves to introduce the cold water to the bottom of the condensing
+device. The tube D serves to carry away the waste water. The tube F serves
+for the introduction of the solvent by means of a small funnel. When
+the solvent is introduced and has boiled for a short time, the tube
+F should be closed. In each of the double conical sections of the
+condenser a circular disk B is found, which causes the water flowing
+from A upward to pass against the metallic surfaces of the condenser.
+<span class="pagenum"><a id="Page_49"></a>[Pg 49]</span></p>
+
+<p>A section of the double conical condenser is shown in the upper right
+hand corner. It is provided with two small hooks <i>hh</i>, soldered on
+the lower surface, by means of which the crucible G can be hung with a
+platinum wire. The condenser is best made smooth and circular in form.</p>
+
+<p>The crucible G, which holds the material to be extracted, can be made
+of platinum, but for sake of economy also of porcelain. The bottom
+of the porcelain crucible is left open excepting a small shelf, as
+indicated, which supports a perforated disk of platinum on which an
+asbestos film is placed.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_23" src="images/fig23.jpg" alt="" width="400" height="643" >
+    <p class="center spb1">Figure 23. Compact Condensing Apparatus.</p>
+</div>
+
+<p>The whole apparatus is of such size as to be easily contained in the
+large test-tube T.</p>
+
+<p><span class="pagenum"><a id="Page_50"></a>[Pg 50]</span>
+The mouth of the test-tube is ground so as to fit as smoothly as
+possible to the ground-brass plate of the metallic condenser P.</p>
+
+<p>In case it is desired to weigh the extract it may be done directly by
+weighing it in the test-tube T after drying in the usual way at the
+end of the extraction; or a glass flask H, made to fit freely into the
+test-tube, may be used, in which case a little mercury is poured into
+the bottom of the tube to seal the space between H and T. To prevent
+spirting of the substance in H, or projecting any of the extracted
+material without or against the bottom of the crucible G, the funnel
+represented by the dotted lines in the right hand section may be used.</p>
+
+<p>Heat may be applied to the test-tube either by hot water, or steam, or
+by a bunsen, which permits of the flame being turned down to minimum
+proportions without danger of burning back. When the test-tube alone
+is used it is advisable to first put into it some fragments of pumice
+stone, particles of platinum foil, or a spoonful of shot, to prevent
+bumping of the liquid when the lamp is used as the source of heat.</p>
+
+<p>Any air which the apparatus contains is pushed out through F when the
+boiling begins, the tube F not being closed until the vapor of the
+liquid has reached its maximum height. With cold water in the condenser
+the vapor of ether very rarely reaches above the lower compartment and
+the vapor of alcohol rarely above the second.</p>
+
+<p>When the plate P is accurately turned so as to fit the ground surface
+of the mouth of T, it is found that ten cubic centimeters of anhydrous
+ether or alcohol are sufficient to make a complete extraction, and
+there is not much loss of solvent in six hours. The thickness of the
+asbestos film in G, or its fineness, is so adjusted as to prevent too
+rapid filtration so that the solvent may just cover the material to
+be extracted, or, after the material is placed in a crucible, a plug
+of extracted glass wool may be placed above it for the purpose of
+distributing the solvent evenly over the surface of the material to be
+extracted and of preventing the escape of fine particles.
+<span class="pagenum"><a id="Page_51"></a>[Pg 51]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_24" src="images/fig24.jpg" alt="" width="600" height="409" >
+    <p class="center spb1">Figure 24. Improved Compact Extraction Apparatus.</p>
+</div>
+
+<p>In very warm weather the apparatus may be arranged as shown in <a href="#FIG_24">figure 24</a>.
+The bath for holding the extraction tubes is made in two parts,
+K and Kʹ. The bath K has a false bottom shown in the dotted line O,
+perforated to receive the ends of the extraction tubes and which holds
+them in place and prevents them from touching the true bottom, where
+they might be unequally heated by the lamp. The upper bath Kʹ has a
+<span class="pagenum"><a id="Page_52"></a>[Pg 52]</span>
+perforated bottom, partly closed with rubber-cloth diaphragms Gʹ Nʹ Hʹ.
+The extraction tubes passing through this bath, water-tight, permit
+broken ice or ice-water to be held about their tops, and thus secure
+a complete condensation of the vapors of the solvent which in warm
+weather might escape the metal condenser. In practice care must be
+taken to avoid enveloping too much of the upper part of the extraction
+tube with the ice-water, otherwise the vapors of the solvent will be
+chiefly condensed on the sides of the extraction tube and will not be
+returned through the sample. It is not often that the upper bath is
+needed, and then only with ether, never with alcohol. This apparatus
+has proved especially useful with alcohol, using, as suggested,
+glycerol in the bath. The details of its further construction and
+arrangement are shown in the <a href="#FIG_24">figure</a>. The extraction tubes
+are most conveniently arranged in a battery of four, one current of cold water
+passing in at A and out at B, serving for all. The bath is supported
+on legs long enough to allow the lamp plenty of room. The details of
+the condenser M are shown in Bʹ, Aʹ, T, Fʹ, and Lʹ. Instead of a gooch
+Lʹ for holding the sample a glass tube R, with a perforated platinum
+disk Q, may be used. The water line in the bath is shown by W. This
+apparatus may be made very cheaply and without greatly impairing its
+efficiency by using a plain concentric condenser and leaving off the
+upper bath Kʹ.</p>
+
+<p><b>42. Solvents Employed.</b>—It has already been intimated that the
+chief solvents employed in the extraction of agricultural samples are
+ether or petroleum and aqueous alcohol. The ether used should be free
+of alcohol and water, the petroleum should be subjected to fractional
+distillation to free it of the parts of very high and very low
+boiling points, and the alcohol as a rule should contain about twenty
+per cent of water.</p>
+
+<p>There are many instances, however, where other solvents should be used.
+The use of aqueous alcohol is sometimes preceded by that of alcohol of
+greater strength or practically free of water. For the extraction of
+soluble carbohydrates (sugars) cold or tepid water is employed, the
+temperature of which is not allowed to rise high enough to act upon
+starch granules. For the solution of the starch itself an acid solvent
+<span class="pagenum"><a id="Page_53"></a>[Pg 53]</span>
+is used at a boiling temperature, whereby the starch molecules undergo
+hydrolysis and form dextrin or soluble sugars (maltose, dextrose). By
+this process also the carbohydrates, whose molecules contain five, or
+some multiple thereof, atoms of carbon form soluble sugars of which
+xylose and arabinose are types. The solvent action of acids followed
+by treatment with dilute alkalies at a boiling temperature, completes
+practically the solution of all the carbohydrate bodies, save cellulose
+and nearly related compounds. The starch carbohydrates are further
+dissolved by the action of certain ferments such as diastase.</p>
+
+<p>Dilute solutions of mineral salts exert a specific solvent action on
+certain nitrogenous compounds and serve to help separate the albuminoid
+bodies into definite groups.</p>
+
+<p>Under the proper headings the uses of these principal solvents will be
+described, but a complete discussion of their action, especially on
+samples of a vegetable origin, should be looked for in works on plant
+analysis.<a id="FNanchor_20" href="#Footnote_20" class="fnanchor">[20]</a></p>
+
+<p>The application of acids and alkalies for the extraction of
+carbohydrates, insoluble in water and alcohol, will be described,
+in the paragraphs devoted to the analysis of fodders and cereals.
+The extraction of these matters, made soluble by ferments, will be
+discussed in the pages devoted to starch and artificial digestion.
+It is thus seen that the general preliminary treatment of a sample
+preparatory to specific methods of examination is confined to drying,
+extraction with ether and alcohol, and incineration.</p>
+
+<p id="P_43"><b>43. Recovery of the Solvent.</b>—In using such solvents as ether,
+chloroform, and others of high value, it is desirable often to recover
+the solvent. Various forms of apparatus are employed for this purpose,
+arranged in such a way as both to secure the solvent and to leave the
+residue in an accessible condition, or in a form suited to weighing
+in quantitive work. When the extractions are made according to the
+improved method of Knorr, the flask containing the extract may be at
+once connected with the apparatus shown in <a href="#FIG_25">figure 25</a>.<a id="FNanchor_21" href="#Footnote_21" class="fnanchor">[21]</a>
+A represents the flask containing the solvent to be recovered, W the
+steam-bath, B the condenser sealed by mercury, M and R the flask
+receiving the products of condensation. It will be found economical
+to save ether, alcohol, and chloroform even when only a few cubic
+centimeters remain after the extraction is complete. In the <a href="#FIG_25">figure</a>
+the neck of the flask A is represented as narrower than it really is.
+The open end of the connecting tube, which is sealed on A by mercury,
+should be the same size as the tube connecting with the condenser in
+the extraction apparatus.
+<span class="pagenum"><a id="Page_54"></a>[Pg 54]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_25" src="images/fig25.jpg" alt="" width="400" height="707" >
+    <p class="center spb1">Figure 25.—Knorr’s Apparatus for<br> Receiving Solvents.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_55"></a>[Pg 55]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_26" src="images/fig26.jpg" alt="" width="500" height="545" >
+    <p class="center spb1">Figure 26. Apparatus for Recovering Solvents<br> from Open Dishes.</p>
+</div>
+
+<p>It often happens that materials which are dissolved by the ordinary
+<span class="pagenum"><a id="Page_56"></a>[Pg 56]</span>
+solvents in use are to be collected in open dishes in order that
+their properties may be studied. At the same time large quantities
+of solvents must be used, and it is desirable to have some method of
+recovering them. The device shown in <a href="#FIG_26">Fig. 26</a> has been found to work
+excellently well for this purpose.<a id="FNanchor_22" href="#Footnote_22" class="fnanchor">[22]</a>
+It consists of a steam-bath, W, and a bottle, B, with the bottom
+cut off, resting on an iron dish, P, containing a small quantity of
+mercury, enough to seal the bottom of the bottle. The dish containing
+the solvent is placed on the mercury, and the bottle placed down over
+it, forming a tight joint. On the application of steam the solvent
+escapes into the condenser, C, and is collected as a liquid in the
+flask A. In very volatile solvents the flask A may be surrounded with
+ice, or ice-cold water passed through the condenser. When an additional
+quantity of the solvent is to be added to the dish for the purpose of
+evaporating it is poured into the funnel F, and the stopcock H opened,
+which allows the material to run into the dish in B without removing
+the bottle. In this way many liters of the solvent may be evaporated
+in any one dish, and the total amount of extract obtained together. At
+the last the bottle B is removed, and the extract which is found in the
+dish is ready for further operations.</p>
+
+<h3>AUTHORITIES CITED IN PART FIRST.</h3>
+
+<div class="footnotes">
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_1" href="#FNanchor_1" class="label">[1]</a>
+Sidersky: Traité d’Analyse des Matières Sucrées, p. 311.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_2" href="#FNanchor_2" class="label">[2]</a>
+Die Agricultur-Chemische Versuchs-Station, Halle a/S., S. 34.
+(Read Dreef instead of Dree.)</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_3" href="#FNanchor_3" class="label">[3]</a>
+Report of Commissioner of Fish and Fisheries, 1888, p.686.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_4" href="#FNanchor_4" class="label">[4]</a>
+Vid. op. cit. 2, p. 14.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_5" href="#FNanchor_5" class="label">[5]</a>
+Journal of the American Chemical Society, Vol. 15, p. 83.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_6" href="#FNanchor_6" class="label">[6]</a>
+Chemical Division, U. S. Department of Agriculture,
+Bulletin No. 28, p. 101.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_7" href="#FNanchor_7" class="label">[7]</a>
+Not yet described in any publication. Presented at 12th annual meeting
+of the Association of Agricultural Chemists, Aug. 7th, 1895.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_8" href="#FNanchor_8" class="label">[8]</a>
+Vid. op. cit. 6, p. 100.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_9" href="#FNanchor_9" class="label">[9]</a>
+Cornell University Agricultural Experiment Station, Bulletin 12.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_10" href="#FNanchor_10" class="label">[10]</a>
+(bis. p. 28). Vid. op. cit. 2, p. 15.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_11" href="#FNanchor_11" class="label">[11]</a>
+Bulletin No. 13, Chemical Division, U. S. Department of Agriculture,
+Part First pp. 85-6.</p>
+</div>
+
+<p class="no-indent"><span class="pagenum"><a id="Page_57"></a>[Pg 57]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_12" href="#FNanchor_12" class="label">[12]</a>
+Bulletin de 1’ Association des Chimistes de Sucrerie, 1893, p. 656.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_13" href="#FNanchor_13" class="label">[13]</a>
+Chemical News, Vol. 52, p. 280.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_14" href="#FNanchor_14" class="label">[14]</a>
+Presented to 12th Annual Convention of the Association of
+Official Agricultural Chemists, Sept. 7th, 1895.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_15" href="#FNanchor_15" class="label">[15]</a>
+Vid. Volume First, p. 411.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_16" href="#FNanchor_16" class="label">[16]</a>
+Vid. op. cit. 2, p. 17.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_17" href="#FNanchor_17" class="label">[17]</a>
+Dragendorff, Plant Analysis.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_18" href="#FNanchor_18" class="label">[18]</a>
+Vid. op. cit. 6, p. 96.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_19" href="#FNanchor_19" class="label">[19]</a>
+Journal of Analytical and Applied Chemistry, Vol. 7, p. 65,
+and Journal of the American Chemical Society, March 1893.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_20" href="#FNanchor_20" class="label">[20]</a>
+Vid. op. cit. 16.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_21" href="#FNanchor_21" class="label">[21]</a>
+Vid. op. cit. 6, p. 99.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_22" href="#FNanchor_22" class="label">[22]</a>
+Vid. op. cit. 6, p. 103.</p>
+</div></div>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum"><a id="Page_58"></a>[Pg 58]</span></p>
+
+<h2 class="nobreak">PART SECOND.<br>
+<span class="h_subtitle">SUGARS AND STARCHES.</span></h2>
+</div>
+
+<p><b>44. Introduction.</b>—Carbohydrates, of which sugars and starches
+are the chief representatives, form the great mass of the results of
+vegetable metabolism. The first functions of the chlorophyll cells of
+the young plant are the condensation of carbon dioxid and water. The
+simplest form of the condensation is formaldehyd, <b>CH₂O</b>. There is no
+convincing evidence, however, that this is the product resulting from
+the functional activity of the chlorophyll cells. The first evidence
+of the condensation is found in more complex molecules; <i>viz.</i>,
+those having six atoms of carbon. It is not the purpose of this work to
+discuss the physiology of this process, but the interested student can
+easily find access to the literature of the subject.<a id="FNanchor_23" href="#Footnote_23" class="fnanchor">[23]</a>
+When a sample of a vegetable nature reaches the analyst he finds by
+far the largest part of its substance composed of these products of
+condensation of the carbon dioxid and water. The sugars, starches,
+pentosans, lignoses, and celluloses all have this common origin. Of
+many air-dried plants these bodies form more than eighty per cent.</p>
+
+<p>In green plants the sugars exist chiefly in the sap. In plants cut
+green and quickly dried by artificial means the sugars are found
+in a solid state. They also exist in the solid state naturally in
+certain sacchariferous seeds. Many sugar-bearing plants when allowed
+to dry spontaneously lose all or the greater part of their sugar by
+fermentation. This is true of sugar cane, sorghum, maize stalks, and
+the like. The starches are found deposited chiefly in tubers, roots or
+seeds. In the potato the starch is in the tuber, in cassava the tuber
+holding the starch is also a root, in maize, rice and other cereals
+the starch is in the seeds. The wood-fibers; <i>viz.</i>, pentosans,
+lignose, cellulose, etc., form the framework and support of the plant
+structure. Of all these carbohydrate bodies the most important as foods
+<span class="pagenum"><a id="Page_59"></a>[Pg 59]</span>
+are the sugars and starches, but a certain degree of digestibility
+cannot be denied to other carbohydrate bodies with the possible
+exception of pure cellulose. In the following paragraphs the general
+principles of determining the sugars and starches will be given and
+afterwards the special processes of extracting these bodies from
+vegetable substances preparatory to quantitive determination.</p>
+
+<p><b>45. Nomenclature.</b>—In speaking of sugars it has been thought
+best to retain for the present the old nomenclature in order to avoid
+confusion. The terms dextrose, levulose, sucrose, etc., will therefore
+be given their commonly accepted significations.</p>
+
+<p>A more scientific nomenclature has recently been proposed by Fischer,
+in which glucose is used as the equivalent of dextrose and fructose
+as the proper name for levulose. All sugars are further classified
+by Fischer into groups according to the number of carbon atoms found
+in the molecule. We have thus trioses, tetroses, pentoses, hexoses,
+etc. Such a sugar as sucrose is called hexobiose by reason of the fact
+that it appears to be formed of two molecules of hexose sugars. For a
+similar reason raffinose would belong to the hexotriose group.<a id="FNanchor_24" href="#Footnote_24" class="fnanchor">[24]</a></p>
+
+<p>Again, the two great classes of sugars as determined by the structure
+of the molecule are termed aldoses and ketoses according to their
+relationship to the aldehyd or ketone bodies.</p>
+
+<p>Since sugars may be optically twinned, that is composed of equal
+molecules of right and left-handed polarizing matter it may happen that
+apparently the same body may deflect the plane of polarization to the
+right, to the left, or show perfect neutrality.</p>
+
+<p>Natural sugars, as a rule, are optically active, but synthetic sugars
+being optically twinned are apt to be neutral to polarized light.</p>
+
+<p>To designate the original optical properties of the body therefore
+the symbols <i>d</i>, <i>l</i>, and <i>i</i>, meaning dextrogyratory,
+levogyratory, and inactive, respectively, are prefixed to the name.
+Thus we may have <i>d</i>, <i>l</i>, or <i>i</i> glucose, <i>d</i>,
+<i>l</i>, or <i>i</i> fructose, and so on.</p>
+
+<p>The sugars that are of interest here belong altogether to the pentose
+and hexose groups; <i>viz.</i>, <b>C₅H₁₀O₅</b> and <b>C₆H₁₂O₆</b>, respectively.
+Of the hexobioses, sucrose, maltose, and lactose are the most important,
+<span class="pagenum"><a id="Page_60"></a>[Pg 60]</span>
+and of the hexotrioses, raffinose. In this manual, unless otherwise
+stated, the term dextrose corresponds to <i>d</i> glucose, and levulose
+to <i>d</i> fructose. In this connection, however, it should be noted
+that the levulose of nature, or that which is formed by the hydrolysis
+of inulin or sucrose is not identical in its optical properties with
+the <i>l</i> fructose of Fischer.</p>
+
+<p><b>46. Preparation of Pure Sugar.</b>—In using the polariscope or in
+testing solutions for the chemical analysis of samples, the analyst
+will be required to keep always on hand some pure sugar. Several
+methods of preparing pure sugar have been proposed. The finest
+granulated sugar of commerce is almost pure. In securing samples for
+examination those should be selected which have had a minimum treatment
+with bluing in manufacture. The best quality of granulated sugar when
+pulverized, washed with ninety-five per cent and then with absolute
+alcohol and dried over sulfuric acid at a temperature not exceeding 50°
+will be found nearly pure. Such a sugar will, as a rule, not contain
+more than one-tenth per cent of impurities, and can be safely used for
+all analytical purposes. It is assumed in the above that the granulated
+sugar is made from sugar cane.</p>
+
+<p>Granulated beet sugars may contain raffinose and so may show a
+polarization in excess of 100. This sugar may be purified by dissolving
+seventy parts by weight in thirty parts of water. The sugar is
+precipitated by adding slowly an equal volume of ninety-six per cent
+alcohol with constant stirring, the temperature of the mixture being
+kept at 60°. While still warm the supernatant liquor is decanted
+and the precipitated sugar washed by decantation several times with
+strong warm alcohol. The sugar, on a filter, is finally washed with
+absolute alcohol and dried in a thin layer over sulfuric acid at from
+35° to 40°. By this process any raffinose which the sugar may have
+contained is completely removed by the warm alcohol. Since beet sugar
+is gradually coming into use in this country it is safer to follow the
+above method with all samples.<a id="FNanchor_25" href="#Footnote_25" class="fnanchor">[25]</a>
+In former times it was customary to prepare pure sugar from the whitest
+crystals of rock candy. These crystals are powdered, dissolved in
+water, filtered, precipitated with alcohol, washed and dried in the
+manner described above.
+<span class="pagenum"><a id="Page_61"></a>[Pg 61]</span></p>
+
+<p><b>47. Classification of Methods.</b>—In the quantitive determination
+of pure sugar the various processes employed may all be grouped
+into three classes. In the first class are included all those which
+deduce the percentage of sugar present from the specific gravity of
+its aqueous solution. The accuracy of this process depends on the
+purity of the material, the proper control of the temperature, and
+the reliability of the instruments employed. The results are obtained
+either directly from the scale of the instruments employed or are
+calculated from the arbitrary or specific gravity numbers observed. It
+is evident that any impurity in the solution would serve to introduce
+an error of a magnitude depending on the percentage of impurity and
+the deviation of the density from that of sugar. The different classes
+of sugars, having different densities in solution, give also different
+readings on the instruments employed. It is evident, therefore, that a
+series of tables of percentages corresponding to the specific gravities
+of the solutions of different sugars would be necessary for exact work.
+Practically, however, the sugar which is most abundant, <i>viz.</i>,
+sucrose, may be taken as a representative of the others and for rapid
+control work the densimetric method is highly useful.</p>
+
+<p>In the second class of methods are grouped all those processes which
+depend upon the property of sugar solutions to rotate the plane of
+polarized light. Natural sugars all have this property and if their
+solutions be found neutral to polarized light it is because they
+contain sugars of opposite polarizing powers of equal intensity. Some
+sugars turn the polarized plane to the right and others to the left,
+and the degree of rotation in each case depends, at equal temperatures
+and densities of the solutions, on the percentages of sugars present.
+In order that the optical examination of a sugar may give correct
+results the solution must be of a known density and free of other
+bodies capable of affecting the plane of polarized light. In the
+following paragraphs an attempt will be made to give in sufficient
+detail the methods of practice of these different processes in so far
+as they are of interest to the agricultural analyst. The number of
+variations, however, in these processes is so great as to make the
+attempt to fully discuss them here impracticable. The searcher for
+<span class="pagenum"><a id="Page_62"></a>[Pg 62]</span>
+additional details should consult the standard works on sugar
+analysis.<a id="FNanchor_26" href="#Footnote_26" class="fnanchor">[26]</a></p>
+
+<p>In the third class of methods are included those which are of a
+chemical nature based either on the reducing power which sugar
+solutions exercise on certain metallic salts, upon the formation of
+certain crystalline and insoluble compounds with other bodies or
+upon fermentation. Under proper conditions solutions of sugar reduce
+solutions of certain metallic salts, throwing out either the metal
+itself or a low oxid thereof. In alkaline solutions of mercury and
+copper, sugars exercise a reducing action, throwing out in the one case
+metallic mercury and in the other cuprous oxid. With phenylhydrazin,
+sugars form definite crystalline compounds, quite insoluble, which
+can be collected, dried and weighed. There is a large number of other
+chemical reactions with sugars such as their union with the earthy
+bases, color reactions with alkalies, oxidation products with acids,
+and so on, which are of great use qualitively and in technological
+processes, but these are of little value in quantitive determinations.</p>
+
+<h3>THE DETERMINATION OF THE PERCENTAGE OF<br>
+SUGAR BY THE DENSITY OF ITS SOLUTION.</h3>
+
+<p id="P_48"><b>48. Principles of the Method.</b>—This method of analysis is
+applied almost exclusively to the examination of one kind of sugar,
+<i>viz.</i>, the common sugar of commerce. This sugar is derived
+chiefly from sugar cane and sugar beets and is known chemically as
+sucrose or saccharose. The method is accurate only when applied to
+solutions of pure sucrose which contain no other bodies. It is evident
+however, that other bodies in solution can be determined by the same
+process, so that the principle of the method is broadly applicable to
+the analyses of any body whatever in a liquid state or in solution.
+Gases, liquids and solids, in solution, can all be determined by
+densimetric methods.</p>
+
+<p>Broadly stated the principle of the method consists in determining the
+specific gravity of the liquid or solution, and thereafter taking the
+percentage of the body in solution from the corresponding specific
+gravity in a table. These tables are carefully prepared by gravimetric
+<span class="pagenum"><a id="Page_63"></a>[Pg 63]</span>
+determinations of the bodies in solution of known densities, varying by
+small amounts and calculation of the percentages for the intervening
+increments or decrements of density. This tabulation is accomplished at
+definite temperatures and the process of analysis secured thereby is
+rapid and accurate, with pure or nearly pure solutions.</p>
+
+<p><b>49. Determination of Density.</b>—While not strictly correct from
+a physical point of view, the terms density and specific gravity are
+here used synonymously and refer to a direct comparison of the weights
+of equal volumes of pure water and of the solution in question, at the
+temperature named. When not otherwise stated, the temperature of the
+solution is assumed to be 15°.5.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_27" src="images/fig27.jpg" alt="" width="500" height="594" >
+    <p class="center spb1">Figure 27. Common Forms of Pyknometers.</p>
+</div>
+
+<p>The simplest method of determining the density of a solution is to
+get the weight of a definite volume thereof. This is conveniently
+accomplished by the use of a pyknometer. A pyknometer is any vessel
+<span class="pagenum"><a id="Page_64"></a>[Pg 64]</span>
+capable of holding a definite volume of a liquid in a form suited
+to weighing. It may be a simple flask with a narrow neck distinctly
+marked, or a flask with a ground perforated stopper, which, when
+inserted, secures always the same volume of liquid contents. A very
+common form of pyknometer is one in which the central stopper carries a
+thermometer and the constancy of volume is secured by a side tubulure
+of very small or even capillary dimensions, which is closed by a ground
+glass cap.</p>
+
+<p>The apparatus may not even be of flask form, but assume a quite
+different shape as in Sprengel’s tube. Pyknometers are often made to
+hold an even number of cubic centimeters, but the only advantage of
+this is in the ease of calculation which it secures. As a rule, it
+will be found necessary to calibrate even these, and then the apparent
+advantage will be easily lost. A flask which is graduated to hold fifty
+cubic centimeters, may, in a few years, change its volume at least
+slightly, due to molecular changes in the glass. Some of the different
+forms of pyknometers are shown in the accompanying figures.</p>
+
+<p>In use the pyknometer should be filled with pure water of the desired
+temperature and weighed. From the total weight the tare of the flask
+and stopper, weighed clean and dry, is to be deducted. The remainder
+is the weight of the volume of water of the temperature noted, which
+the pyknometer holds. The weight of the solution under examination is
+taken in the same way and at the same temperature, and thus a direct
+comparison between the two liquids is secured.</p>
+
+<table class="spb1 fs_90">
+   <tbody><tr>
+      <td class="tdl"><i>Example.</i>—Let the weight of the pyknometer be&emsp;&nbsp;</td>
+      <td class="tdr">15.2985</td>
+      <td class="tdl_wsp">grams.</td>
+   </tr><tr>
+      <td class="tdl_ws2">and its weight with pure water at 15°.5 be</td>
+      <td class="tdr">26.9327</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl_ws1">Then the weight of water is</td>
+      <td class="tdr">11.6342</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl_ws1">The weight filled with the sugar solution is</td>
+      <td class="tdr">28.3263</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl_ws1">Then the weight of the sugar solution is</td>
+      <td class="tdr">13.0278</td>
+      <td class="tdc">”</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The specific gravity of the sugar solution is therefore, 13.0278 ÷
+11.6342 = 1.1198.</p>
+
+<p>For strictly accurate results the weight must be corrected for the
+volume of air displaced, or in other words, be reduced to weights in
+vacuo. This however is unnecessary for the ordinary operations of
+agricultural analysis.
+<span class="pagenum"><a id="Page_65"></a>[Pg 65]</span></p>
+
+<p>If the volume of the pyknometer be desired, it can be calculated from
+the weight of pure water which it holds, one cubic centimeter of pure
+water weighing one gram at 4°.</p>
+
+<p>The weights of one cubic centimeter of water at each degree of
+temperature from 1° to 40°, are given in the following table:</p>
+
+<p class="f120 spb1"><b><span class="smcap">Table Showing Weights of  One<br>
+Cubic Centimeter of Pure Water<br> at Temperatures Varying from<br> 1° To 40°.</span></b></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb">&nbsp; Temperature. &nbsp;</th>
+      <th class="tdc bb">Weight,<br> Gram.</th>
+      <th class="tdc bb">&nbsp; Temperature. &nbsp;</th>
+      <th class="tdc bb">Weight,<br> Gram.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">&#8199;0°</td>
+      <td class="tdc">0.999871</td>
+      <td class="tdc">21°</td>
+      <td class="tdc">0.998047</td>
+   </tr><tr>
+      <td class="tdc">&#8199;1°</td>
+      <td class="tdc">0.999928</td>
+      <td class="tdc">22°</td>
+      <td class="tdc">0.997826</td>
+   </tr><tr>
+      <td class="tdc">&#8199;2°</td>
+      <td class="tdc">0.999969</td>
+      <td class="tdc">23°</td>
+      <td class="tdc">0.997601</td>
+   </tr><tr>
+      <td class="tdc">&#8199;3°</td>
+      <td class="tdc">0.999991</td>
+      <td class="tdc">24°</td>
+      <td class="tdc">0.997367</td>
+   </tr><tr>
+      <td class="tdc">&#8199;4°</td>
+      <td class="tdc">1.000000</td>
+      <td class="tdc">25°</td>
+      <td class="tdc">0.997120</td>
+   </tr><tr>
+      <td class="tdc">&#8199;5°</td>
+      <td class="tdc">0.999990</td>
+      <td class="tdc">26°</td>
+      <td class="tdc">0.996866</td>
+   </tr><tr>
+      <td class="tdc">&#8199;6°</td>
+      <td class="tdc">0.999970</td>
+      <td class="tdc">27°</td>
+      <td class="tdc">0.996603</td>
+   </tr><tr>
+      <td class="tdc">&#8199;7°</td>
+      <td class="tdc">0.999933</td>
+      <td class="tdc">28°</td>
+      <td class="tdc">0.998331</td>
+   </tr><tr>
+      <td class="tdc">&#8199;8°</td>
+      <td class="tdc">0.999886</td>
+      <td class="tdc">29°</td>
+      <td class="tdc">0.995051</td>
+   </tr><tr>
+      <td class="tdc">&#8199;9°</td>
+      <td class="tdc">0.999824</td>
+      <td class="tdc">30°</td>
+      <td class="tdc">0.995765</td>
+   </tr><tr>
+      <td class="tdc">10°</td>
+      <td class="tdc">0.999747</td>
+      <td class="tdc">31°</td>
+      <td class="tdc">0.995401</td>
+   </tr><tr>
+      <td class="tdc">11°</td>
+      <td class="tdc">0.999655</td>
+      <td class="tdc">32°</td>
+      <td class="tdc">0.995087</td>
+   </tr><tr>
+      <td class="tdc">12°</td>
+      <td class="tdc">0.999549</td>
+      <td class="tdc">33°</td>
+      <td class="tdc">0.994765</td>
+   </tr><tr>
+      <td class="tdc">13°</td>
+      <td class="tdc">0.999430</td>
+      <td class="tdc">34°</td>
+      <td class="tdc">0.994436</td>
+   </tr><tr>
+      <td class="tdc">14°</td>
+      <td class="tdc">0.999299</td>
+      <td class="tdc">35°</td>
+      <td class="tdc">0.994098</td>
+   </tr><tr>
+      <td class="tdc">15°</td>
+      <td class="tdc">0.999160</td>
+      <td class="tdc">36°</td>
+      <td class="tdc">0.993720</td>
+   </tr><tr>
+      <td class="tdc">16°</td>
+      <td class="tdc">0.999002</td>
+      <td class="tdc">37°</td>
+      <td class="tdc">0.993370</td>
+   </tr><tr>
+      <td class="tdc">17°</td>
+      <td class="tdc">0.998841</td>
+      <td class="tdc">38°</td>
+      <td class="tdc">0.993030</td>
+   </tr><tr>
+      <td class="tdc">18°</td>
+      <td class="tdc">0.998654</td>
+      <td class="tdc">39°</td>
+      <td class="tdc">0.992680</td>
+   </tr><tr>
+      <td class="tdc">19°</td>
+      <td class="tdc">0.998460</td>
+      <td class="tdc">40°</td>
+      <td class="tdc">0.992330</td>
+   </tr><tr>
+      <td class="tdc">20°</td>
+      <td class="tdc">0.998259</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>From the table and the weight of water found, the volume of the
+pyknometer is easily calculated.</p>
+
+<p><i>Example.</i>—Let the weight of water found be 11.72892 grams, and
+the temperature 20°. Then the volume of the flask is equal to 11.72892
+÷ 0.998259, <i>viz.</i>, 11.95 cubic centimeters.</p>
+
+<p><b>50. Use of Pyknometer at High Temperatures.</b>—It is often found
+desirable to determine the density of a liquid at temperatures above
+that of the laboratory, <i>e. g.</i>, at the boiling-point of water.
+This is easily accomplished by following the directions given below:</p>
+
+<p><i>Weight of Flask.</i>—Use a small pyknometer of from twenty-five to
+thirty cubic centimeters capacity. The stopper should be beveled to a
+<span class="pagenum"><a id="Page_66"></a>[Pg 66]</span>
+fine edge on top and the lower end should be slightly concave to
+avoid any trapping of air. The flask is to be thoroughly washed with
+hot water, alcohol and ether, and then dried for some time at 100°.
+After cooling in a desiccator the weight of the flask and stopper is
+accurately determined.<a id="FNanchor_27" href="#Footnote_27" class="fnanchor">[27]</a></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_28" src="images/fig28.jpg" alt="" width="400" height="509" >
+    <p class="center spb1">Figure 28. Bath for Pyknometers.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_67"></a>[Pg 67]</span>
+<i>Weight of Water.</i>—The flask in an appropriate holder, <a href="#FIG_28">Fig. 28</a>,
+conveniently made of galvanized iron, is filled with freshly boiled and
+hot distilled water and placed in a bath of pure, very hot distilled
+water, in such a way that it is entirely surrounded by the liquid with
+the exception of the top.</p>
+
+<p>The water of the bath is kept in brisk ebullition for thirty minutes,
+any evaporation from the flask being replaced by the addition of
+boiling distilled water. The stopper should be kept for a few minutes
+before use in hot distilled water and is then inserted, the flask
+removed, wiped dry, and, after it is nearly cooled to room temperature,
+placed in the balance and weighed when balance temperature is reached.
+A convenient size of holder will enable the analyst to use eight or ten
+flasks at once. The temperature at which water boils in each locality
+may also be determined; but unless at very high altitudes, or on days
+of unusual barometric disturbance the variations will not be great, and
+will not appreciably affect the results.</p>
+
+<p id="P_51"><b>51. Alternate Method of Estimating the Weight of Water in
+Flasks.</b>—Formulas for calculating the volume <i>V</i>, in cubic
+centimeters, of a glass vessel from the weight <i>P</i> of water at the
+temperature <i>t</i> contained therein, and the volume <i>Vʹ</i> at any
+other temperature <i>t’</i> are given by Landolt and Börnstein.<a id="FNanchor_28" href="#Footnote_28" class="fnanchor">[28]</a>
+They are as follows:</p>
+
+<table class="spb1 fs_120">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>V</i> = <i>P</i> &nbsp;</td>
+      <td class="tdc bb"><i>p</i></td>
+   </tr><tr>
+      <td class="tdc"><i>d</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1 fs_120">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>Vʹ</i> = <i>P</i> &nbsp;</td>
+      <td class="tdc bb"><i>p</i></td>
+      <td class="tdl" rowspan="2">&nbsp; [1 + <i>γ</i> (<i>tʹ</i>- <i>t</i>)];</td>
+   </tr><tr>
+      <td class="tdc"><i>d</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="no-indent">in which <i>p</i> = weight (in brass weights) of
+one cubic centimeter <b>H₂O</b> in vacuo. This is so nearly one gram that
+it will not affect the result in the fifth place of decimals and may
+therefore be disregarded. Hence the formula stands:</p>
+
+<table class="spb1 fs_120">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>Vʹ</i> = <i>P</i> &nbsp;</td>
+      <td class="tdc bb">1</td>
+      <td class="tdl" rowspan="2">&nbsp; [1 + <i>γ</i> (<i>tʹ</i>- <i>t</i>)]</td>
+   </tr><tr>
+      <td class="tdc"><i>d</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p><i>d</i> = density of water at temperature <i>t</i>.</p>
+
+<p><i>γ</i> = 0.000025, the cubical expansion coefficient of glass.</p>
+
+<p>From this volume the weight of the water may be readily obtained by
+referring to tables 13, 14 and 15<i>a</i> in Landolt and Börnstein’s book.
+<span class="pagenum"><a id="Page_68"></a>[Pg 68]</span></p>
+
+<p><b>52. Example Showing Determination of Specific Gravity of a
+Fat.</b>—The flask is emptied of its water, rinsed with alcohol and
+ether, and dried again for a few minutes at 100°. It is then filled
+with the dry, hot, fresh-filtered fat, which should be entirely free
+from air bubbles.</p>
+
+<p>The stoppered flask is then replaced in the water-bath, kept for thirty
+minutes at the temperature of boiling water, removed, and treated as
+above. The weight of fat having been determined, the specific gravity
+is obtained by dividing it by the weight of water previously found.</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdc fs_110" colspan="2"><i>Example.</i></td>
+   </tr><tr>
+      <td class="tdr" colspan="2">Grams.</td>
+   </tr><tr>
+      <td class="tdl">Weight of flask, dry</td>
+      <td class="tdr">10.0197</td>
+   </tr><tr>
+      <td class="tdl">Weight of flask, plus water</td>
+      <td class="tdr">37.3412</td>
+   </tr><tr>
+      <td class="tdl">Weight of water</td>
+      <td class="tdr">27.3215</td>
+   </tr><tr>
+      <td class="tdl">Weight of flask, plus fat</td>
+      <td class="tdr">34.6111</td>
+   </tr><tr>
+      <td class="tdl">Weight of fat</td>
+      <td class="tdr">24.5914</td>
+   </tr><tr>
+      <td class="tdl">Specific gravity = 24.5914 ÷ 27.3215 = &nbsp;</td>
+      <td class="tdr">0.90008.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The weight of the flask dry and empty and the weight of water at 99° to
+100° contained therein may be used constantly if great care be taken in
+handling and cleaning the apparatus.</p>
+
+<table class="spb2">
+   <tbody><tr>
+      <td class="tdc fs_110" colspan="2"><i>Example</i>.</td>
+   </tr><tr>
+      <td class="tdr" colspan="2">Grams.</td>
+   </tr><tr>
+      <td class="tdl">Weight of flask, dry and empty</td>
+      <td class="tdr">10.0028</td>
+   </tr><tr>
+      <td class="tdl">Weight of flask after three weeks’ use &nbsp;</td>
+      <td class="tdr">10.0030</td>
+   </tr>
+ </tbody>
+</table>
+
+<div class="figcenter smcap">
+    <img id="FIG_29" src="images/fig29.jpg" alt="" width="600" height="171" >
+    <p class="center spb1">Figure 29. Aereometers, Pyknometers, and
+                           Hydrostatic Balance.</p>
+</div>
+
+<p id="P_53"><b>53. Determination of Density by the Hydrostatic Balance.</b>—While
+the pyknometer is useful in control work and in fixing standards of
+comparison, it is not used extensively in practical work. Quicker
+methods of determination are desired in such work, and these are
+found in the use of other forms of apparatus. A convenient method of
+operation consists in determining the weight of a sinker, whose exact
+<span class="pagenum"><a id="Page_69"></a>[Pg 69]</span>
+weights in air and in pure water of a definite temperature, have been
+previously determined. The instrument devised by Mohr and modified by
+Westphal, is based upon that principle, and is extensively used in
+practical work. The construction of this apparatus and also that of the
+pyknometers and areometers is shown in the illustrations, figures
+<a href="#FIG_29">29</a> and <a href="#FIG_30">30</a>.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_30" src="images/fig30.jpg" alt="" width="500" height="498" >
+    <p class="center spb1">Figure 30. Hydrostatic Balance.</p>
+</div>
+
+<p>The weight of the sinker is so adjusted that the index of the balance
+arm marks zero when the sinker is wholly immersed in pure water at the
+standard temperature. The density of a solution of sugar at the same
+temperature, is then determined by placing the rider-weights on the
+<span class="pagenum"><a id="Page_70"></a>[Pg 70]</span>
+divided arm of the balance, until the index again marks zero. The
+density can then be read directly from the position of the weights in
+the arm of the balance or calculated therefrom.</p>
+
+<p><b>54. The Areometric Method.</b>—The most rapid method of determining
+the density of a solution and the one in most common use, is based
+on the distance to which a heavy bulb with a slender graduated stem
+will sink therein. An instrument of this kind is called an areometer.
+Many forms of this instrument are employed but they all depend on the
+same principle and differ only in the manner of graduation. The one of
+widest application has the stem graduated in such a manner as to give
+directly the specific gravity of the solution in which it is placed.</p>
+
+<p>Others are made with a special graduation giving directly the
+percentage of solid matter in the solution. These instruments can be
+used only for the special purposes for which they are constructed.
+Other forms are provided with an arbitrary graduation, the numbers
+of which by appropriate tables can be converted into expressions of
+specific gravity or of per cents of dissolved matters. It is not
+practicable to give here, a discussion of the principles of the
+construction of areometers.<a id="FNanchor_29" href="#Footnote_29" class="fnanchor">[29]</a>
+The two which are commonly used, are the baumé hydrometer and the
+balling or brix spindle.</p>
+
+<p>In the baumé instrument the zero of the scale is fixed at the point
+marked by the surface of distilled water at 15°, and the point to which
+it sinks in pure monohydrated sulfuric acid at the same temperature is
+marked 66, corresponding to a specific gravity of 1.8427.</p>
+
+<p>The specific gravity corresponding to any degree of the scale, may be
+calculated in the absence of a table giving it, by the following formula</p>
+
+<table class="spb1 fs_120">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>P</i> = &nbsp;</td>
+      <td class="tdc bb">144.3</td>
+      <td class="tdl_wsp" rowspan="2">.</td>
+   </tr><tr>
+      <td class="tdc">144.3 - <i>d</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p>In this formula <i>P</i> is the density and <i>d</i> the degree of the
+scale.<a id="FNanchor_30" href="#Footnote_30" class="fnanchor">[30]</a>
+In former times the baumé instruments were graduated with a solution
+of common salt and a different formula was employed for calculating
+specific gravity, but these older instruments are no longer in common
+use.</p>
+
+<p>The following table shows the specific gravities of solutions
+corresponding to baumé degrees from 1° to 75° consecutively<a id="FNanchor_31" href="#Footnote_31" class="fnanchor">[31]</a>:</p>
+
+<p><span class="pagenum"><a id="Page_71"></a>[Pg 71]</span></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc">Degree<br>baumé</th>
+      <th class="tdc">&nbsp; Specific &nbsp;<br>gravity</th>
+      <th class="tdc">Degree<br>baumé</th>
+      <th class="tdc">&nbsp; Specific &nbsp;<br>gravity</th>
+      <th class="tdc">Degree<br>baumé</th>
+      <th class="tdc">&nbsp; Specific &nbsp;<br>gravity</th>
+      <th class="tdc">Degree<br>baumé</th>
+      <th class="tdc">&nbsp; Specific &nbsp;<br>gravity</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">&#8199;0</td> <td class="tdc">1.0000</td>
+      <td class="tdc">19</td> <td class="tdc">1.1516</td>
+      <td class="tdc">38</td> <td class="tdc">1.3574</td>
+      <td class="tdc">57</td> <td class="tdc">1.6527</td>
+   </tr><tr>
+      <td class="tdc">&#8199;1</td> <td class="tdc">1.0069</td>
+      <td class="tdc">20</td> <td class="tdc">1.1608</td>
+      <td class="tdc">39</td> <td class="tdc">1.3703</td>
+      <td class="tdc">58</td> <td class="tdc">1.6719</td>
+   </tr><tr>
+      <td class="tdc">&#8199;2</td> <td class="tdc">1.0140</td>
+      <td class="tdc">21</td> <td class="tdc">1.1702</td>
+      <td class="tdc">40</td> <td class="tdc">1.3834</td>
+      <td class="tdc">59</td> <td class="tdc">1.6915</td>
+   </tr><tr>
+      <td class="tdc">&#8199;3</td> <td class="tdc">1.0212</td>
+      <td class="tdc">22</td> <td class="tdc">1.1798</td>
+      <td class="tdc">41</td> <td class="tdc">1.3968</td>
+      <td class="tdc">60</td> <td class="tdc">1.7115</td>
+   </tr><tr>
+      <td class="tdc">&#8199;4</td> <td class="tdc">1.0285</td>
+      <td class="tdc">23</td> <td class="tdc">1.1895</td>
+      <td class="tdc">42</td> <td class="tdc">1.4104</td>
+      <td class="tdc">61</td> <td class="tdc">1.7321</td>
+   </tr><tr>
+      <td class="tdc">&#8199;5</td> <td class="tdc">1.0358</td>
+      <td class="tdc">24</td> <td class="tdc">1.1994</td>
+      <td class="tdc">43</td> <td class="tdc">1.4244</td>
+      <td class="tdc">62</td> <td class="tdc">1.7531</td>
+   </tr><tr>
+      <td class="tdc">&#8199;6</td> <td class="tdc">1.0433</td>
+      <td class="tdc">25</td> <td class="tdc">1.2095</td>
+      <td class="tdc">44</td> <td class="tdc">1.4386</td>
+      <td class="tdc">63</td> <td class="tdc">1.7748</td>
+   </tr><tr>
+      <td class="tdc">&#8199;7</td> <td class="tdc">1.0509</td>
+      <td class="tdc">26</td> <td class="tdc">1.2197</td>
+      <td class="tdc">45</td> <td class="tdc">1.4530</td>
+      <td class="tdc">64</td> <td class="tdc">1.7968</td>
+   </tr><tr>
+      <td class="tdc">&#8199;8</td> <td class="tdc">1.0586</td>
+      <td class="tdc">27</td> <td class="tdc">1.2301</td>
+      <td class="tdc">46</td> <td class="tdc">1.4678</td>
+      <td class="tdc">65</td> <td class="tdc">1.8194</td>
+   </tr><tr>
+      <td class="tdc">&#8199;9</td> <td class="tdc">1.0665</td>
+      <td class="tdc">28</td> <td class="tdc">1.2407</td>
+      <td class="tdc">47</td> <td class="tdc">1.4829</td>
+      <td class="tdc">66</td> <td class="tdc">1.8427</td>
+   </tr><tr>
+      <td class="tdc">10</td> <td class="tdc">1.0744</td>
+      <td class="tdc">29</td> <td class="tdc">1.2514</td>
+      <td class="tdc">48</td> <td class="tdc">1.4983</td>
+      <td class="tdc">67</td> <td class="tdc">1.8665</td>
+   </tr><tr>
+      <td class="tdc">11</td> <td class="tdc">1.0825</td>
+      <td class="tdc">30</td> <td class="tdc">1.2624</td>
+      <td class="tdc">49</td> <td class="tdc">1.5140</td>
+      <td class="tdc">68</td> <td class="tdc">1.8909</td>
+   </tr><tr>
+      <td class="tdc">12</td> <td class="tdc">1.0906</td>
+      <td class="tdc">31</td> <td class="tdc">1.2735</td>
+      <td class="tdc">50</td> <td class="tdc">1.5301</td>
+      <td class="tdc">69</td> <td class="tdc">1.9161</td>
+   </tr><tr>
+      <td class="tdc">13</td> <td class="tdc">1.0989</td>
+      <td class="tdc">32</td> <td class="tdc">1.2849</td>
+      <td class="tdc">51</td> <td class="tdc">1.5465</td>
+      <td class="tdc">70</td> <td class="tdc">1.9418</td>
+   </tr><tr>
+      <td class="tdc">14</td> <td class="tdc">1.1074</td>
+      <td class="tdc">33</td> <td class="tdc">1.2964</td>
+      <td class="tdc">52</td> <td class="tdc">1.5632</td>
+      <td class="tdc">71</td> <td class="tdc">1.9683</td>
+   </tr><tr>
+      <td class="tdc">15</td> <td class="tdc">1.1159</td>
+      <td class="tdc">34</td> <td class="tdc">1.3081</td>
+      <td class="tdc">53</td> <td class="tdc">1.5802</td>
+      <td class="tdc">72</td> <td class="tdc">1.9955</td>
+   </tr><tr>
+      <td class="tdc">16</td> <td class="tdc">1.1246</td>
+      <td class="tdc">35</td> <td class="tdc">1.3201</td>
+      <td class="tdc">54</td> <td class="tdc">1.5978</td>
+      <td class="tdc">73</td> <td class="tdc">2.0235</td>
+   </tr><tr>
+      <td class="tdc">17</td> <td class="tdc">1.1335</td>
+      <td class="tdc">36</td> <td class="tdc">1.3323</td>
+      <td class="tdc">55</td> <td class="tdc">1.6157</td>
+      <td class="tdc">74</td> <td class="tdc">2.0523</td>
+   </tr><tr>
+      <td class="tdc">18</td> <td class="tdc">1.1424</td>
+      <td class="tdc">37</td> <td class="tdc">1.3447</td>
+      <td class="tdc">56</td> <td class="tdc">1.6340</td>
+      <td class="tdc">75</td> <td class="tdc">2.0819</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>55. Correction for Temperature.</b>—The baumé hydrometer should be
+used at the temperature for which it is graduated, usually 15°. In this
+country the mean temperature of our working rooms is above 15°. The
+liquid in the hydrometer flask should therefore be cooled to a trifle
+below 15°, or kept in a bath exactly at 15° while the observation is
+made. When this is not convenient, the observation may be made at any
+temperature, and the reading corrected as follows: When the temperature
+is above 15° multiply the difference between the observed temperature
+and fifteen, by 0.0471 and add the product to the observed reading of
+the baumé hydrometer; when the temperature on the other hand, is below
+fifteen, the corresponding product is subtracted.<a id="FNanchor_32" href="#Footnote_32" class="fnanchor">[32]</a></p>
+
+<p><b>56. The Balling or Brix Hydrometer.</b>—The object of the balling
+or brix instrument is to give in direct percentages the solid matter
+in solution. It is evident that for this purpose the instrument must
+be graduated for a particular kind of material, since ten per cent of
+sugar in solution, might have a very different specific gravity from a
+similar quantity of another body. Instruments of this kind graduated
+for pure sugar, find a large use in technical sugar analysis. To attain
+<span class="pagenum"><a id="Page_72"></a>[Pg 72]</span>
+a greater accuracy and avoid an instrument with too long a stem, the
+brix hydrometers are made in sets. A convenient arrangement is to have
+a set of three graduated as follows; one from 0° to 30°, one from 25°
+to 50°, and one from 45° to 85°. When the percentage of solid matter
+dissolved is over seventy the readings of the scale are not very reliable.</p>
+
+<p><b>57. Correction for Temperature.</b>—The brix as the baumé scale is
+graduated at a fixed temperature. This temperature is usually 17°.5.
+The following table shows the corrections to be applied to the scale
+reading when made at any other temperature:<a id="FNanchor_33" href="#Footnote_33" class="fnanchor">[33]</a></p>
+
+<p class="f120 spa1"><b><span class="smcap">Per Cent of Sugar in Solution.</span></b></p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdc">&nbsp;0.</td> <td class="tdc">&nbsp;5.</td>
+      <td class="tdc">10.</td> <td class="tdc">15.</td>
+      <td class="tdc">20.</td> <td class="tdc">25.</td>
+      <td class="tdc">30.</td> <td class="tdc">35.</td>
+      <td class="tdc">40.</td> <td class="tdc">50.</td>
+      <td class="tdc">60.</td> <td class="tdc">70.</td>
+      <td class="tdc">75.</td>
+   </tr><tr>
+      <td class="tdl">Temp.</td>
+      <td class="tdc fs_110" colspan="13"><i>To be subtracted from the degree read.</i></td>
+   </tr><tr>
+      <td class="tdl_wsp">0°</td>
+      <td class="tdc">&nbsp;0.17&nbsp;</td> <td class="tdc bl">&nbsp;0.30&nbsp;</td>
+      <td class="tdc bl">&nbsp;0.41&nbsp;</td> <td class="tdc bl">&nbsp;0.52&nbsp;</td>
+      <td class="tdc bl">&nbsp;0.62&nbsp;</td> <td class="tdc bl">&nbsp;0.72&nbsp;</td>
+      <td class="tdc bl">&nbsp;0.82&nbsp;</td> <td class="tdc bl">&nbsp;0.92&nbsp;</td>
+      <td class="tdc bl">&nbsp;0.98&nbsp;</td> <td class="tdc bl">&nbsp;1.11&nbsp;</td>
+      <td class="tdc bl">&nbsp;1.22&nbsp;</td> <td class="tdc bl">&nbsp;1.25&nbsp;</td>
+      <td class="tdc bl">&nbsp;1.29&nbsp;</td>
+   </tr><tr>
+      <td class="tdl_wsp">5°</td>
+      <td class="tdc">0.23</td> <td class="tdc bl">0.30</td>
+      <td class="tdc bl">0.37</td> <td class="tdc bl">0.44</td>
+      <td class="tdc bl">0.52</td> <td class="tdc bl">0.59</td>
+      <td class="tdc bl">0.65</td> <td class="tdc bl">0.72</td>
+      <td class="tdc bl">0.75</td> <td class="tdc bl">0.80</td>
+      <td class="tdc bl">0.88</td> <td class="tdc bl">0.91</td>
+      <td class="tdc bl">0.94</td>
+   </tr><tr>
+      <td class="tdl">10°</td>
+      <td class="tdc">0.20</td> <td class="tdc bl">0.26</td>
+      <td class="tdc bl">0.29</td> <td class="tdc bl">0.33</td>
+      <td class="tdc bl">0.36</td> <td class="tdc bl">0.39</td>
+      <td class="tdc bl">0.42</td> <td class="tdc bl">0.45</td>
+      <td class="tdc bl">0.48</td> <td class="tdc bl">0.50</td>
+      <td class="tdc bl">0.54</td> <td class="tdc bl">0.58</td>
+      <td class="tdc bl">0.61</td>
+   </tr><tr>
+      <td class="tdl">11°</td>
+      <td class="tdc">0.18</td> <td class="tdc bl">0.23</td>
+      <td class="tdc bl">0.26</td> <td class="tdc bl">0.28</td>
+      <td class="tdc bl">0.31</td> <td class="tdc bl">0.34</td>
+      <td class="tdc bl">0.36</td> <td class="tdc bl">0.39</td>
+      <td class="tdc bl">0.41</td> <td class="tdc bl">0.43</td>
+      <td class="tdc bl">0.47</td> <td class="tdc bl">0.50</td>
+      <td class="tdc bl">0.53</td>
+   </tr><tr>
+      <td class="tdl bb">12°</td>
+      <td class="tdc bb">0.16</td> <td class="tdc bl bb">0.20</td>
+      <td class="tdc bl bb">0.22</td> <td class="tdc bl bb">0.24</td>
+      <td class="tdc bl bb">0.26</td> <td class="tdc bl bb">0.29</td>
+      <td class="tdc bl bb">0.31</td> <td class="tdc bl bb">0.33</td>
+      <td class="tdc bl bb">0.34</td> <td class="tdc bl bb">0.36</td>
+      <td class="tdc bl bb">0.40</td> <td class="tdc bl bb">0.42</td>
+      <td class="tdc bl bb">0.46</td>
+   </tr><tr>
+      <td class="tdl">13°</td>
+      <td class="tdc">0.14</td> <td class="tdc bl">0.18</td>
+      <td class="tdc bl">0.19</td> <td class="tdc bl">0.21</td>
+      <td class="tdc bl">0.22</td> <td class="tdc bl">0.24</td>
+      <td class="tdc bl">0.26</td> <td class="tdc bl">0.27</td>
+      <td class="tdc bl">0.28</td> <td class="tdc bl">0.29</td>
+      <td class="tdc bl">0.33</td> <td class="tdc bl">0.35</td>
+      <td class="tdc bl">0.39</td>
+   </tr><tr>
+      <td class="tdl">14°</td>
+      <td class="tdc">0.12</td> <td class="tdc bl">0.15</td>
+      <td class="tdc bl">0.16</td> <td class="tdc bl">0.17</td>
+      <td class="tdc bl">0.18</td> <td class="tdc bl">0.19</td>
+      <td class="tdc bl">0.21</td> <td class="tdc bl">0.22</td>
+      <td class="tdc bl">0.22</td> <td class="tdc bl">0.23</td>
+      <td class="tdc bl">0.26</td> <td class="tdc bl">0.28</td>
+      <td class="tdc bl">0.32</td>
+   </tr><tr>
+      <td class="tdl">15°</td>
+      <td class="tdc">0.09</td> <td class="tdc bl">0.11</td>
+      <td class="tdc bl">0.12</td> <td class="tdc bl">0.14</td>
+      <td class="tdc bl">0.14</td> <td class="tdc bl">0.15</td>
+      <td class="tdc bl">0.16</td> <td class="tdc bl">0.16</td>
+      <td class="tdc bl">0.17</td> <td class="tdc bl">0.17</td>
+      <td class="tdc bl">0.19</td> <td class="tdc bl">0.21</td>
+      <td class="tdc bl">0.25</td>
+   </tr><tr>
+      <td class="tdl">16°</td>
+      <td class="tdc">0.06</td> <td class="tdc bl">0.07</td>
+      <td class="tdc bl">0.08</td> <td class="tdc bl">0.09</td>
+      <td class="tdc bl">0.10</td> <td class="tdc bl">0.10</td>
+      <td class="tdc bl">0.11</td> <td class="tdc bl">0.12</td>
+      <td class="tdc bl">0.12</td> <td class="tdc bl">0.12</td>
+      <td class="tdc bl">0.14</td> <td class="tdc bl">0.16</td>
+      <td class="tdc bl">0.18</td>
+   </tr><tr>
+      <td class="tdl">17°</td>
+      <td class="tdc">0.02</td> <td class="tdc bl">0.02</td>
+      <td class="tdc bl">0.03</td> <td class="tdc bl">0.03</td>
+      <td class="tdc bl">0.03</td> <td class="tdc bl">0.04</td>
+      <td class="tdc bl">0.04</td> <td class="tdc bl">0.04</td>
+      <td class="tdc bl">0.04</td> <td class="tdc bl">0.04</td>
+      <td class="tdc bl">0.05</td> <td class="tdc bl">0.05</td>
+      <td class="tdc bl">0.06</td>
+   </tr><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdc fs_110" colspan="13"><i>To be added to the degree read.</i></td>
+   </tr><tr>
+      <td class="tdl">18°</td>
+      <td class="tdc">0.02</td> <td class="tdc bl">0.03</td>
+      <td class="tdc bl">0.03</td> <td class="tdc bl">0.03</td>
+      <td class="tdc bl">0.03</td> <td class="tdc bl">0.03</td>
+      <td class="tdc bl">0.03</td> <td class="tdc bl">0.03</td>
+      <td class="tdc bl">0.03</td> <td class="tdc bl">0.03</td>
+      <td class="tdc bl">0.03</td> <td class="tdc bl">0.03</td>
+      <td class="tdc bl">0.02</td>
+   </tr><tr>
+      <td class="tdl">19°</td>
+      <td class="tdc">0.06</td> <td class="tdc bl">0.08</td>
+      <td class="tdc bl">0.08</td> <td class="tdc bl">0.09</td>
+      <td class="tdc bl">0.09</td> <td class="tdc bl">0.10</td>
+      <td class="tdc bl">0.10</td> <td class="tdc bl">0.10</td>
+      <td class="tdc bl">0.10</td> <td class="tdc bl">0.10</td>
+      <td class="tdc bl">0.10</td> <td class="tdc bl">0.08</td>
+      <td class="tdc bl">0.06</td>
+   </tr><tr>
+      <td class="tdl">20°</td>
+      <td class="tdc">0.11</td> <td class="tdc bl">0.14</td>
+      <td class="tdc bl">0.15</td> <td class="tdc bl">0.17</td>
+      <td class="tdc bl">0.17</td> <td class="tdc bl">0.18</td>
+      <td class="tdc bl">0.18</td> <td class="tdc bl">0.18</td>
+      <td class="tdc bl">0.19</td> <td class="tdc bl">0.19</td>
+      <td class="tdc bl">0.18</td> <td class="tdc bl">0.15</td>
+      <td class="tdc bl">0.11</td>
+   </tr><tr>
+      <td class="tdl">21°</td>
+      <td class="tdc">0.16</td> <td class="tdc bl">0.20</td>
+      <td class="tdc bl">0.22</td> <td class="tdc bl">0.24</td>
+      <td class="tdc bl">0.24</td> <td class="tdc bl">0.25</td>
+      <td class="tdc bl">0.25</td> <td class="tdc bl">0.25</td>
+      <td class="tdc bl">0.26</td> <td class="tdc bl">0.26</td>
+      <td class="tdc bl">0.25</td> <td class="tdc bl">0.22</td>
+      <td class="tdc bl">0.18</td>
+   </tr><tr>
+      <td class="tdl">22°</td>
+      <td class="tdc">0.21</td> <td class="tdc bl">0.26</td>
+      <td class="tdc bl">0.28</td> <td class="tdc bl">0.31</td>
+      <td class="tdc bl">0.31</td> <td class="tdc bl">0.32</td>
+      <td class="tdc bl">0.32</td> <td class="tdc bl">0.32</td>
+      <td class="tdc bl">0.33</td> <td class="tdc bl">0.34</td>
+      <td class="tdc bl">0.32</td> <td class="tdc bl">0.29</td>
+      <td class="tdc bl">0.25</td>
+   </tr><tr>
+      <td class="tdl">23°</td>
+      <td class="tdc">0.27</td> <td class="tdc bl">0.32</td>
+      <td class="tdc bl">0.35</td> <td class="tdc bl">0.37</td>
+      <td class="tdc bl">0.38</td> <td class="tdc bl">0.39</td>
+      <td class="tdc bl">0.39</td> <td class="tdc bl">0.39</td>
+      <td class="tdc bl">0.40</td> <td class="tdc bl">0.42</td>
+      <td class="tdc bl">0.39</td> <td class="tdc bl">0.36</td>
+      <td class="tdc bl">0.33</td>
+   </tr><tr>
+      <td class="tdl">24°</td>
+      <td class="tdc">0.32</td> <td class="tdc bl">0.38</td>
+      <td class="tdc bl">0.41</td> <td class="tdc bl">0.43</td>
+      <td class="tdc bl">0.44</td> <td class="tdc bl">0.46</td>
+      <td class="tdc bl">0.46</td> <td class="tdc bl">0.47</td>
+      <td class="tdc bl">0.47</td> <td class="tdc bl">0.50</td>
+      <td class="tdc bl">0.46</td> <td class="tdc bl">0.43</td>
+      <td class="tdc bl">0.40</td>
+   </tr><tr>
+      <td class="tdl bb">25°</td>
+      <td class="tdc bb">0.37</td> <td class="tdc bl bb">0.44</td>
+      <td class="tdc bl bb">0.47</td> <td class="tdc bl bb">0.49</td>
+      <td class="tdc bl bb">0.51</td> <td class="tdc bl bb">0.53</td>
+      <td class="tdc bl bb">0.54</td> <td class="tdc bl bb">0.55</td>
+      <td class="tdc bl bb">0.55</td> <td class="tdc bl bb">0.58</td>
+      <td class="tdc bl bb">0.54</td> <td class="tdc bl bb">0.51</td>
+      <td class="tdc bl bb">0.48</td>
+   </tr><tr>
+      <td class="tdl">26°</td>
+      <td class="tdc">0.43</td> <td class="tdc bl">0.50</td>
+      <td class="tdc bl">0.54</td> <td class="tdc bl">0.56</td>
+      <td class="tdc bl">0.58</td> <td class="tdc bl">0.60</td>
+      <td class="tdc bl">0.61</td> <td class="tdc bl">0.62</td>
+      <td class="tdc bl">0.62</td> <td class="tdc bl">0.66</td>
+      <td class="tdc bl">0.62</td> <td class="tdc bl">0.58</td>
+      <td class="tdc bl">0.55</td>
+   </tr><tr>
+      <td class="tdl">27°</td>
+      <td class="tdc">0.49</td> <td class="tdc bl">0.57</td>
+      <td class="tdc bl">0.61</td> <td class="tdc bl">0.63</td>
+      <td class="tdc bl">0.65</td> <td class="tdc bl">0.68</td>
+      <td class="tdc bl">0.68</td> <td class="tdc bl">0.69</td>
+      <td class="tdc bl">0.70</td> <td class="tdc bl">0.74</td>
+      <td class="tdc bl">0.70</td> <td class="tdc bl">0.65</td>
+      <td class="tdc bl">0.62</td>
+   </tr><tr>
+      <td class="tdl">28°</td>
+      <td class="tdc">0.56</td> <td class="tdc bl">0.64</td>
+      <td class="tdc bl">0.68</td> <td class="tdc bl">0.70</td>
+      <td class="tdc bl">0.72</td> <td class="tdc bl">0.76</td>
+      <td class="tdc bl">0.76</td> <td class="tdc bl">0.78</td>
+      <td class="tdc bl">0.78</td> <td class="tdc bl">0.82</td>
+      <td class="tdc bl">0.78</td> <td class="tdc bl">0.72</td>
+      <td class="tdc bl">0.70</td>
+   </tr><tr>
+      <td class="tdl">29°</td>
+      <td class="tdc">0.63</td> <td class="tdc bl">0.71</td>
+      <td class="tdc bl">0.75</td> <td class="tdc bl">0.78</td>
+      <td class="tdc bl">0.79</td> <td class="tdc bl">0.84</td>
+      <td class="tdc bl">0.84</td> <td class="tdc bl">0.86</td>
+      <td class="tdc bl">0.86</td> <td class="tdc bl">0.90</td>
+      <td class="tdc bl">0.88</td> <td class="tdc bl">0.80</td>
+      <td class="tdc bl">0.78</td>
+   </tr><tr>
+      <td class="tdl">30°</td>
+      <td class="tdc">0.70</td> <td class="tdc bl">0.78</td>
+      <td class="tdc bl">0.82</td> <td class="tdc bl">0.87</td>
+      <td class="tdc bl">0.87</td> <td class="tdc bl">0.92</td>
+      <td class="tdc bl">0.92</td> <td class="tdc bl">0.94</td>
+      <td class="tdc bl">0.94</td> <td class="tdc bl">0.98</td>
+      <td class="tdc bl">0.94</td> <td class="tdc bl">0.88</td>
+      <td class="tdc bl">0.86</td>
+   </tr><tr>
+      <td class="tdl">35°</td>
+      <td class="tdc">1.10</td> <td class="tdc bl">1.17</td>
+      <td class="tdc bl">1.22</td> <td class="tdc bl">1.24</td>
+      <td class="tdc bl">1.30</td> <td class="tdc bl">1.32</td>
+      <td class="tdc bl">1.33</td> <td class="tdc bl">1.35</td>
+      <td class="tdc bl">1.36</td> <td class="tdc bl">1.39</td>
+      <td class="tdc bl">1.34</td> <td class="tdc bl">1.27</td>
+      <td class="tdc bl">1.25</td>
+   </tr><tr>
+      <td class="tdl">40°</td>
+      <td class="tdc">1.50</td> <td class="tdc bl">1.61</td>
+      <td class="tdc bl">1.67</td> <td class="tdc bl">1.71</td>
+      <td class="tdc bl">1.73</td> <td class="tdc bl">1.79</td>
+      <td class="tdc bl">1.79</td> <td class="tdc bl">1.80</td>
+      <td class="tdc bl">1.82</td> <td class="tdc bl">1.83</td>
+      <td class="tdc bl">1.78</td> <td class="tdc bl">1.69</td>
+      <td class="tdc bl">1.65</td>
+   </tr><tr>
+      <td class="tdl">50°</td> <td class="tdc">—</td>
+      <td class="tdc bl">2.65</td> <td class="tdc bl">2.71</td>
+      <td class="tdc bl">2.74</td> <td class="tdc bl">2.78</td>
+      <td class="tdc bl">2.80</td> <td class="tdc bl">2.80</td>
+      <td class="tdc bl">2.80</td> <td class="tdc bl">2.80</td>
+      <td class="tdc bl">2.79</td> <td class="tdc bl">2.70</td>
+      <td class="tdc bl">2.56</td> <td class="tdc bl">2.51</td>
+   </tr><tr>
+      <td class="tdl">60°</td>
+      <td class="tdc">—</td> <td class="tdc bl">3.87</td>
+      <td class="tdc bl">3.88</td> <td class="tdc bl">3.88</td>
+      <td class="tdc bl">3.88</td> <td class="tdc bl">3.88</td>
+      <td class="tdc bl">3.88</td> <td class="tdc bl">3.88</td>
+      <td class="tdc bl">3.90</td> <td class="tdc bl">3.82</td>
+      <td class="tdc bl">3.70</td> <td class="tdc bl">3.43</td>
+      <td class="tdc bl">3.41</td>
+   </tr><tr>
+      <td class="tdl">70°</td>
+      <td class="tdc">—</td> <td class="tdc bl">—</td>
+      <td class="tdc bl">5.18</td> <td class="tdc bl">5.20</td>
+      <td class="tdc bl">5.14</td> <td class="tdc bl">5.13</td>
+      <td class="tdc bl">5.10</td> <td class="tdc bl">5.08</td>
+      <td class="tdc bl">5.06</td> <td class="tdc bl">4.90</td>
+      <td class="tdc bl">4.72</td> <td class="tdc bl">4.47</td>
+      <td class="tdc bl">4.35</td>
+   </tr><tr>
+      <td class="tdl">80°</td>
+      <td class="tdc">—</td> <td class="tdc bl">—</td>
+      <td class="tdc bl">6.62</td> <td class="tdc bl">6.59</td>
+      <td class="tdc bl">6.54</td> <td class="tdc bl">6.16</td>
+      <td class="tdc bl">6.38</td> <td class="tdc bl">6.30</td>
+      <td class="tdc bl">6.26</td> <td class="tdc bl">6.06</td>
+      <td class="tdc bl">5.82</td> <td class="tdc bl">5.50</td>
+      <td class="tdc bl">5.33</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_73"></a>[Pg 73]</span>
+According to observations of Gerlach, the correction for temperature
+varies with the concentration of the solution and the range of
+temperature as shown in the table.</p>
+
+<p id="P_58"><b>58. Comparison of Brix and Baumé Degrees.</b>—The following table
+shows the degree baumé and the specific gravity of a sugar solution
+for each degree brix (per cent of sugar in solution) from zero to
+ninety-five:<a id="FNanchor_34" href="#Footnote_34" class="fnanchor">[34]</a></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb">Degree<br>brix.</th>
+      <th class="tdc bb">&nbsp; Degree &nbsp;<br>baumé.</th>
+      <th class="tdc bb">&nbsp; Specific &nbsp;<br>gravity</th>
+      <th class="tdc bl bb">&nbsp; Degree &nbsp;<br>brix.</th>
+      <th class="tdc bb">Degree<br>baumé.</th>
+      <th class="tdc bb">&nbsp; Specific &nbsp;<br>gravity</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">&#8199;1.0</td> <td class="tdc">&#8199;0.6</td>
+      <td class="tdc">1.00388</td>
+      <td class="tdc bl">37.0</td> <td class="tdc">20.7</td>
+      <td class="tdc">1.16413</td>
+   </tr><tr>
+      <td class="tdc">&#8199;2.0</td> <td class="tdc">&#8199;1.1</td>
+      <td class="tdc">1.00779</td>
+      <td class="tdc bl">38.0</td> <td class="tdc">21.2</td>
+      <td class="tdc">1.16920</td>
+   </tr><tr>
+      <td class="tdc">&#8199;3.0</td> <td class="tdc">&#8199;1.7</td>
+      <td class="tdc">1.01173</td>
+      <td class="tdc bl">39.0</td> <td class="tdc">21.8</td>
+      <td class="tdc">1.17430</td>
+   </tr><tr>
+      <td class="tdc">&#8199;4.0</td> <td class="tdc">&#8199;2.3</td>
+      <td class="tdc">1.01570</td>
+      <td class="tdc bl">40.0</td> <td class="tdc">22.3</td>
+      <td class="tdc">1.17943</td>
+   </tr><tr>
+      <td class="tdc">&#8199;5.0</td> <td class="tdc">&#8199;2.8</td>
+      <td class="tdc">1.01970</td>
+      <td class="tdc bl">41.0</td> <td class="tdc">22.9</td>
+      <td class="tdc">1.18460</td>
+   </tr><tr>
+      <td class="tdc">&#8199;6.0</td> <td class="tdc">&#8199;3.4</td>
+      <td class="tdc">1.02373</td>
+      <td class="tdc bl">42.0</td> <td class="tdc">23.4</td>
+      <td class="tdc">1.18981</td>
+   </tr><tr>
+      <td class="tdc">&#8199;7.0</td> <td class="tdc">&#8199;4.0</td>
+      <td class="tdc">1.02779</td>
+      <td class="tdc bl">43.0</td> <td class="tdc">24.0</td>
+      <td class="tdc">1.19505</td>
+   </tr><tr>
+      <td class="tdc">&#8199;8.0</td> <td class="tdc">&#8199;4.5</td>
+      <td class="tdc">1.03187</td>
+      <td class="tdc bl">44.0</td> <td class="tdc">24.5</td>
+      <td class="tdc">1.20033</td>
+   </tr><tr>
+      <td class="tdc">&#8199;9.0</td> <td class="tdc">&#8199;5.1</td>
+      <td class="tdc">1.03599</td>
+      <td class="tdc bl">45.0</td> <td class="tdc">25.0</td>
+      <td class="tdc">1.20565</td>
+   </tr><tr>
+      <td class="tdc">10.0</td> <td class="tdc">&#8199;5.7</td>
+      <td class="tdc">1.04014</td>
+      <td class="tdc bl">46.0</td> <td class="tdc">25.6</td>
+      <td class="tdc">1.21100</td>
+   </tr><tr>
+      <td class="tdc">11.0</td> <td class="tdc">&#8199;6.2</td>
+      <td class="tdc">1.04431</td>
+      <td class="tdc bl">47.0</td> <td class="tdc">26.1</td>
+      <td class="tdc">1.21639</td>
+   </tr><tr>
+      <td class="tdc">12.0</td> <td class="tdc">&#8199;6.8</td>
+      <td class="tdc">1.04852</td>
+      <td class="tdc bl">48.0</td> <td class="tdc">26.6</td>
+      <td class="tdc">1.22182</td>
+   </tr><tr>
+      <td class="tdc">13.0</td> <td class="tdc">&#8199;7.4</td>
+      <td class="tdc">1.05276</td>
+      <td class="tdc bl">49.0</td> <td class="tdc">27.2</td>
+      <td class="tdc">1.22128</td>
+   </tr><tr>
+      <td class="tdc">14.0</td> <td class="tdc">&#8199;7.9</td>
+      <td class="tdc">1.05703</td>
+      <td class="tdc bl">50.0</td> <td class="tdc">27.7</td>
+      <td class="tdc">1.23278</td>
+   </tr><tr>
+      <td class="tdc">15.0</td> <td class="tdc">&#8199;8.5</td>
+      <td class="tdc">1.06133</td>
+      <td class="tdc bl">51.0</td> <td class="tdc">28.2</td>
+      <td class="tdc">1.23832</td>
+   </tr><tr>
+      <td class="tdc">16.0</td> <td class="tdc">&#8199;9.0</td>
+      <td class="tdc">1.06566</td>
+      <td class="tdc bl">52.0</td> <td class="tdc">28.8</td>
+      <td class="tdc">1.24390</td>
+   </tr><tr>
+      <td class="tdc">17.0</td> <td class="tdc">&#8199;9.6</td>
+      <td class="tdc">1.07002</td>
+      <td class="tdc bl">53.0</td> <td class="tdc">29.3</td>
+      <td class="tdc">1.24951</td>
+   </tr><tr>
+      <td class="tdc">18.0</td> <td class="tdc">10.1</td>
+      <td class="tdc">1.07441</td>
+      <td class="tdc bl">54.0</td> <td class="tdc">29.8</td>
+      <td class="tdc">1.25517</td>
+   </tr><tr>
+      <td class="tdc">19.0</td> <td class="tdc">10.7</td>
+      <td class="tdc">1.07884</td>
+      <td class="tdc bl">55.0</td> <td class="tdc">30.4</td>
+      <td class="tdc">1.26086</td>
+   </tr><tr>
+      <td class="tdc">20.0</td> <td class="tdc">11.3</td>
+      <td class="tdc">1.08329</td>
+      <td class="tdc bl">56.0</td> <td class="tdc">30.9</td>
+      <td class="tdc">1.26658</td>
+   </tr><tr>
+      <td class="tdc">21.0</td> <td class="tdc">11.8</td>
+      <td class="tdc">1.08778</td>
+      <td class="tdc bl">57.0</td> <td class="tdc">31.4</td>
+      <td class="tdc">1.27235</td>
+   </tr><tr>
+      <td class="tdc">22.0</td> <td class="tdc">12.4</td>
+      <td class="tdc">1.09231</td>
+      <td class="tdc bl">58.0</td> <td class="tdc">31.9</td>
+      <td class="tdc">1.27816</td>
+   </tr><tr>
+      <td class="tdc">23.0</td> <td class="tdc">13.0</td>
+      <td class="tdc">1.09686</td>
+      <td class="tdc bl">59.0</td> <td class="tdc">32.5</td>
+      <td class="tdc">1.28400</td>
+   </tr><tr>
+      <td class="tdc">24.0</td> <td class="tdc">13.5</td>
+      <td class="tdc">1.10145</td>
+      <td class="tdc bl">60.0</td> <td class="tdc">33.0</td>
+      <td class="tdc">1.28989</td>
+   </tr><tr>
+      <td class="tdc">25.0</td> <td class="tdc">14.1</td>
+      <td class="tdc">1.10607</td>
+      <td class="tdc bl">61.0</td> <td class="tdc">33.5</td>
+      <td class="tdc">1.29581</td>
+   </tr><tr>
+      <td class="tdc">26.0</td> <td class="tdc">14.6</td>
+      <td class="tdc">1.11072</td>
+      <td class="tdc bl">62.0</td> <td class="tdc">34.0</td>
+      <td class="tdc">1.30177</td>
+   </tr><tr>
+      <td class="tdc">27.0</td> <td class="tdc">15.2</td>
+      <td class="tdc">1.11541</td>
+      <td class="tdc bl">63.0</td> <td class="tdc">34.5</td>
+      <td class="tdc">1.30177</td>
+   </tr><tr>
+      <td class="tdc">28.0</td> <td class="tdc">15.7</td>
+      <td class="tdc">1.12013</td>
+      <td class="tdc bl">64.0</td> <td class="tdc">35.1</td>
+      <td class="tdc">1.31381</td>
+   </tr><tr>
+      <td class="tdc">29.0</td> <td class="tdc">16.3</td>
+      <td class="tdc">1.12488</td>
+      <td class="tdc bl">65.0</td> <td class="tdc">35.6</td>
+      <td class="tdc">1.31989</td>
+   </tr><tr>
+      <td class="tdc">30.0</td> <td class="tdc">16.8</td>
+      <td class="tdc">1.12967</td>
+      <td class="tdc bl">66.0</td> <td class="tdc">36.1</td>
+      <td class="tdc">1.32601</td>
+   </tr><tr>
+      <td class="tdc">31.0</td> <td class="tdc">17.4</td>
+      <td class="tdc">1.13449</td>
+      <td class="tdc bl">67.0</td> <td class="tdc">36.6</td>
+      <td class="tdc">1.33217</td>
+   </tr><tr>
+      <td class="tdc">32.0</td> <td class="tdc">18.0</td>
+      <td class="tdc">1.13934</td>
+      <td class="tdc bl">68.0</td> <td class="tdc">37.1</td>
+      <td class="tdc">1.33836</td>
+   </tr><tr>
+      <td class="tdc">33.0</td> <td class="tdc">18.5</td>
+      <td class="tdc">1.14423</td>
+      <td class="tdc bl">69.0</td> <td class="tdc">37.6</td>
+      <td class="tdc">1.34460</td>
+   </tr><tr>
+      <td class="tdc">34.0</td> <td class="tdc">19.1</td>
+      <td class="tdc">1.14915</td>
+      <td class="tdc bl">70.0</td> <td class="tdc">38.1</td>
+      <td class="tdc">1.35088</td>
+   </tr><tr>
+      <td class="tdc">35.0</td> <td class="tdc">19.6</td>
+      <td class="tdc">1.15411</td>
+      <td class="tdc bl">71.0</td> <td class="tdc">38.6</td>
+      <td class="tdc">1.35720</td>
+   </tr><tr>
+      <td class="tdc">36.0</td> <td class="tdc">20.1</td>
+      <td class="tdc">1.15911</td>
+      <td class="tdc bl">72.0</td> <td class="tdc">39.1</td>
+      <td class="tdc">1.36355
+                  <span class="pagenum"><a id="Page_74"></a>[Pg 74]</span></td>
+   </tr><tr>
+      <td class="tdc" colspan="3">&nbsp;</td>
+      <td class="tdc bl" colspan="3">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">73.0</td> <td class="tdc">39.6</td>
+      <td class="tdc">1.36995</td>
+      <td class="tdc bl">85.0</td> <td class="tdc">45.5</td>
+      <td class="tdc">1.44986</td>
+   </tr><tr>
+      <td class="tdc">74.0</td> <td class="tdc">40.1</td>
+      <td class="tdc">1.37639</td>
+      <td class="tdc bl">86.0</td> <td class="tdc">46.0</td>
+      <td class="tdc">1.45678</td>
+   </tr><tr>
+      <td class="tdc">75.0</td> <td class="tdc">40.6</td>
+      <td class="tdc">1.38287</td>
+      <td class="tdc bl">87.0</td> <td class="tdc">46.5</td>
+      <td class="tdc">1.46374</td>
+   </tr><tr>
+      <td class="tdc">76.0</td> <td class="tdc">41.1</td>
+      <td class="tdc">1.38939</td>
+      <td class="tdc bl">88.0</td> <td class="tdc">47.0</td>
+      <td class="tdc">1.47074</td>
+   </tr><tr>
+      <td class="tdc">77.0</td> <td class="tdc">41.6</td>
+      <td class="tdc">1.39595</td>
+      <td class="tdc bl">89.0</td> <td class="tdc">47.5</td>
+      <td class="tdc">1.47778</td>
+   </tr><tr>
+      <td class="tdc">78.0</td> <td class="tdc">42.1</td>
+      <td class="tdc">1.40254</td>
+      <td class="tdc bl">90.0</td> <td class="tdc">49.9</td>
+      <td class="tdc">1.48486</td>
+   </tr><tr>
+      <td class="tdc">79.0</td> <td class="tdc">42.6</td>
+      <td class="tdc">1.40918</td>
+      <td class="tdc bl">91.0</td> <td class="tdc">48.4</td>
+      <td class="tdc">1.49199</td>
+   </tr><tr>
+      <td class="tdc">80.0</td> <td class="tdc">43.1</td>
+      <td class="tdc">1.41586</td>
+      <td class="tdc bl">92.0</td> <td class="tdc">48.9</td>
+      <td class="tdc">1.49915</td>
+   </tr><tr>
+      <td class="tdc">81.0</td> <td class="tdc">43.6</td>
+      <td class="tdc">1.42258</td>
+      <td class="tdc bl">93.0</td> <td class="tdc">49.3</td>
+      <td class="tdc">1.50635</td>
+   </tr><tr>
+      <td class="tdc">82.0</td> <td class="tdc">44.1</td>
+      <td class="tdc">1.42934</td>
+      <td class="tdc bl">94.0</td> <td class="tdc">49.8</td>
+      <td class="tdc">1.51359</td>
+   </tr><tr>
+      <td class="tdc">83.0</td> <td class="tdc">44.6</td>
+      <td class="tdc">1.43614</td>
+      <td class="tdc bl">95.0</td> <td class="tdc">50.3</td>
+      <td class="tdc">1.52087</td>
+   </tr><tr>
+      <td class="tdc">84.0</td> <td class="tdc">45.1</td>
+      <td class="tdc">1.44298</td>
+      <td class="tdc bl">&nbsp;</td> <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>59. Error Due to Impurities.</b>—The fact that equal per cents
+of solid bodies in solution affect the specific gravity in different
+degrees has already been noted. The specific gravities of the solutions
+of the common sugars, however, are so nearly the same for equal per
+cents of solid matter in solution as to render the use of a brix
+hydrometer quite general for technical purpose. For the mineral salts
+which often occur in sugar solutions the case is quite different. A
+twenty per cent solution of cane sugar at 17°.5 has a specific gravity
+1.08329 and of dextrose 1.08310, practically identical. But a solution
+of calcium acetate of similar strength has a specific gravity of
+1.0874; of sodium sulfate 1.0807, and of potassium nitrate 1.1359.
+This latter number would correspond to a sugar content of nearly
+twenty-seven per cent. The brix scale can, therefore, be regarded as
+giving only approximately the percentage of solid matter in sugar
+solutions and, while useful in technical work, should never be relied
+upon for exact analytical data.</p>
+
+<h3>THE DETERMINATION OF SUGAR<br> WITH POLARIZED LIGHT.</h3>
+
+<p><b>60. Optical Properties of Natural Sugars.</b>—The solutions of all
+natural sugars have the property of deflecting the plane of polarized
+light and the degree of deflection corresponds to the quantity of sugar
+in solution. By measuring the amplitude of the rotation produced the
+percentage of sugar in the solution can be determined. In order to
+secure accuracy in the determinations it is necessary that only one
+kind of sugar be present, or, if more than one, that the quantities of
+all but one be determined by other means, and the disturbances produced
+<span class="pagenum"><a id="Page_75"></a>[Pg 75]</span>
+thereby in the total rotation be properly arranged. In point of fact
+the process in practice is applied chiefly to cane and milk sugars,
+both of which occur in nature in an approximately pure state. The
+process is also useful in determining cane sugar when mixed with
+other kinds, by reason of the fact that this sugar after hydrolysis
+by treatment with a weak acid for a long or a strong acid for a short
+time, definitely changes its rotating power. Since, by the same
+treatment, the rotating power of other sugars which may be present is
+only slightly altered, the total disturbance produced is approximately
+due to the inversion of the cane sugar.</p>
+
+<p>Dextrose and maltose arising from the hydrolysis of starch may also
+be determined with a fair degree of accuracy by their deportment
+with polarized light. When a solution of natural sugars shows
+negative results when examined with polarized light, it is due to an
+admixture of two or more sugars of opposite polarizing powers in such
+proportions as to produce neutrality. This condition often occurs
+in the examination of honeys or in submitting artificial sugars to
+polarimetric observations. In the latter case the neutrality is caused
+by the tendency manifested by artificially produced sugars to form twin
+compounds of optically opposite qualities.</p>
+
+<p>The instrument used for measuring the degree of deflection produced in
+a plane of polarized light is called a polariscope, polarimeter, or
+optical saccharimeter. For a theoretical discussion of the principles
+of polarization and the application of these principles in the
+construction of polariscopes, the reader is referred to the standard
+works on optics and the construction of optical instruments.<a id="FNanchor_35" href="#Footnote_35" class="fnanchor">[35]</a>
+For the purposes of this work a description of the instruments commonly
+employed and the methods of using them will be sufficient.</p>
+
+<p><b>61. Polarized Light.</b>—When a ray of light has been repeatedly
+reflected from bright surfaces or when it passes through certain
+crystalline bodies it acquires peculiar properties and is said to be
+polarized.</p>
+
+<p>Polarization is therefore a term applied to a phenomenon of light, in
+which the vibrations of the ether are supposed to be restricted to a
+<span class="pagenum"><a id="Page_76"></a>[Pg 76]</span>
+particular form of an ellipse whose axes remain fixed in direction. If
+the ellipse become a straight line it is called plane polarization.
+This well-known phenomenon is most easily produced by a nicol prism,
+consisting of a cut crystal of calcium carbonate (Iceland spar). This
+rhombohedral crystal, the natural ends of which form angles of 71° and
+109°, respectively, with the opposite edges of its principal section,
+is prepared as follows:</p>
+
+<p>The ends of the crystals are ground until the angles just mentioned
+become 68° and 112°. The crystal is then divided diagonally at right
+angles with the planes of the ends and with the principal section, and
+after the new surfaces are polished they are joined again by canada
+balsam. The principal section of this prism passes through the shorter
+diagonal of the two rhombic ends. If now a ray of light fall on one
+of the ends of this prism, parallel with the edge of its longer side,
+it suffers double refraction, and each ray is plane polarized, the
+one at right angles with the other. That part of the entering ray of
+light which is most refracted is called the ordinary and the other the
+extraordinary ray. The refractive index of the film of balsam being
+intermediate between those of the rays, permits the total reflection of
+the ordinary ray, which, passing to the blackened sides of the prism,
+is absorbed. The extraordinary ray passes the film of balsam without
+deviation and emerges from the prism in a direction parallel with the
+incident ray, having, however, only half of its luminous intensity.</p>
+
+<p>Two such prisms, properly mounted, furnish the essential parts of a
+polarizing apparatus. They are called the polarizer and the analyzer,
+respectively.</p>
+
+<p>If now the plane of vibration in each prism be regarded as coincident
+with its principal section, the following phenomena are observed:
+If the prisms are so placed that the principal sections lie in the
+prolongation of the same plane, then the extraordinary polarized ray
+from the polarizer passes into the analyzer, which practically may
+be regarded in this position as a continuation of the same prism.
+It happens, therefore, that the extraordinary polarized ray passes
+through the analyzer exactly as it did through the polarizer, and is
+not reflected by the film of balsam, but emerges from the analyzer in
+<span class="pagenum"><a id="Page_77"></a>[Pg 77]</span>
+seemingly the same condition as from the polarizer. If now the analyzer
+be rotated 180°, bringing the principal section again in the same
+plane, the same phenomenon is observed. But if the rotation be in
+either direction only 90°, then the polarized ray from the first prism,
+incident on the second, deports itself exactly as the ordinary ray,
+and on meeting the film of balsam is totally reflected. The field of
+vision, therefore, is perfectly dark.</p>
+
+<p>In all other inclinations of the planes of the principal sections of
+the two prisms the ray incident in the analyzer is separated into
+two, an ordinary and extraordinary, varying in luminous intensity in
+proportion to the square of the cosine of the angle of the two planes.</p>
+
+<div class="figleft smcap">
+    <img id="FIG_31" src="images/fig31.jpg" alt="" width="200" height="531" >
+    <p class="center spb1">Figure 31. Course<br> of Rays of Light<br> In a Nicol.</p>
+</div>
+
+<p>Thus, by gradually turning the analyzer, the field of vision passes
+slowly from maximum luminosity to complete obscurity. The expression
+crossed nicols refers to the latter condition of the field of vision.</p>
+
+<p><b>62. Description of the Prism.</b>—In a nicol made as described
+above, <a href="#FIG_31">Fig. 31</a>, suppose a ray of light parallel with the longer
+side of the prism be incident to the end <i>a</i> <i>b</i> at <i>m</i>. By the
+double refracting power of the spar the ray is divided into two, which
+traverse the first half of the prism. The two rays are polarized at
+right angles to one another. The less refracted ray when it strikes the
+film of Canada balsam passes through it without interference. The more
+refracted ray strikes the balsam at <i>o</i> at such an angle as to be
+totally reflected and made to pass out of the prism in the direction
+<span class="pagenum"><a id="Page_78"></a>[Pg 78]</span>
+<i>o r</i>. If the prism be blackened at the surface the ray will be
+entirely absorbed. The other ray passes on through the other half of
+the prism and emerges in the direction of <i>qs</i>. It is evident that
+the emergent light from a nicol has only half the illuminating power
+possessed by the immergent rays.</p>
+
+<p>The polarized plane of light from the nicol just described may be
+regarded as passing also into a second nicol of essentially the same
+construction as the first.</p>
+
+<p>This second nicol, called the analyzer, is so constructed as to revolve
+freely about its longitudinal axis, and is attached to a graduated
+circle in such a way that the degree of rotation can be accurately
+read. If the planes of polarization of the two nicols are coincident
+when prolonged, the ray of light passing from the first nicol will pass
+through the second practically unchanged in character or intensity. If,
+however, the analyzing nicol be turned until the plane of polarization
+is at right angles to that of the polarizer the immergent ray will
+suffer refraction in such a manner as to be totally reflected when
+reaching the film of balsam and will be thus entirely lost. In making
+a complete revolution of the analyzer, therefore, two positions of
+maximum intensity of light and two of darkness will be observed. In
+intermediate positions the ray immergent to the analyzer will be
+separated as in the first instance into two rays <i>g p</i> varying
+intensities, one of which will be always totally reflected.</p>
+
+<div class="figright smcap">
+    <img id="FIG_32" src="images/fig32.jpg" alt="" width="200" height="431" >
+    <p class="center spb1">Figure 32. Theory of<br> the Nicol.</p>
+</div>
+
+<p>In <a href="#FIG_32">Fig. 32</a> is given a more detailed illustration of the
+action of the rays of light. The film of balsam is represented as enlarged and of
+the thickness <i>bb</i>. Draw the perpendiculars represented by the dotted
+lines <i>n</i>₁ <i>n</i>ʹ₁, <i>n</i>₂ <i>n</i>ʹ₂, <i>n</i>₃ <i>n</i>ʹ₃
+and <i>n</i>₄ <i>n</i>ʹ₄. In passing into the prism at <i>m</i> both
+<span class="pagenum"><a id="Page_79"></a>[Pg 79]</span>
+refracted rays are bent towards the normal <i>m n</i>ʹ₁. The degree of
+deflection depends on the refractive index of the two rays 1.52 and
+1.66 respectively. The refractive index of the extraordinary ray in
+calcspar being 1.52, and in Canada balsam 1.54, it suffers but little
+disturbance in passing from one to the other. On the other hand the
+balsam, being considerably less refractive for the ordinary ray than
+the calcspar, causes that ray to diverge outwards from the normal
+<i>o n</i>ʹ₂, and to such a degree as to suffer total reflection. The
+critical angle, that is the angle at which a ray issuing from a more
+refractive into a less refractive medium, emerges just parallel to the
+bounding surfaces, depends on the relative index of refraction. In the
+case under consideration the ratio for balsam and spar is 1.54/1.66 =
+0.928 = sin 68°. Therefore the limiting value of <i>m o</i> <i>n</i>₃
+so that <i>m o</i> may just emerge in the direction <i>od</i> is 68°.
+If now <i>mo</i> were parallel to <i>o d</i> the angle <i>m o n</i>,
+would be just 68°, being opposite <i>b a d</i>. which has been ground
+to 68° in the construction of the prism. But in passing into the prism,
+<i>m o</i> is refracted so that the angle <i>m o n</i>₃ is greater
+than <i>b a d</i>. It is therefore always certain that by grinding
+<i>b a d</i> to 68° the ordinary ray <i>m o</i> will be with certainty
+entirely thrown out in every case. In respect of the analyzing nicol
+the following additional observations will be found useful. In all
+uniaxial crystals there are two directions at right angles to each
+other, one of greatest and one of least resistance to the propagation
+of luminous vibrations. These planes are in the direction of the
+principal axis and at right angles thereto. Only light vibrating in
+these two directions can be transmitted through calcspar; and all
+incident light propagated by vibrations in a plane at any other angle
+to the principal section is resolved into two such component rays. But
+the velocities of transmission in the two directions are unequal, that
+is, the refractive index of the spar for the two rays is different. If
+the analyzing nicol be so adjusted as to receive the emergent light
+from the polarizer when the corresponding planes of the two prisms are
+coincident when extended, the emergent extraordinary ray falling into
+a plane of the same resistance as that it had just left is propagated
+through the second nicol with the same velocity that it passed the
+<span class="pagenum"><a id="Page_80"></a>[Pg 80]</span>
+first one. It is therefore similarly refracted. If, however, the
+two prisms be so arranged that corresponding planes cross then the
+extraordinary ray falls into a plane which it traverses with greater
+velocity than it had before and is accordingly refracted and takes the
+course which ends in total reflection at the film of balsam. No light
+therefore can pass through the prism in that position. If any other
+substance, as for instance a solution of sugar, capable of rotating
+a plane of polarized light, be interposed between the two nicols the
+effect produced is the same as if the analyzer had been turned to a
+corresponding degree. When the analyzer is turned to that degree the
+corresponding planes again coincide and the light passes. This is the
+principle on which the construction of all polarizing instruments is
+based.<a id="FNanchor_36" href="#Footnote_36" class="fnanchor">[36]</a></p>
+
+<p><b>63. The Polariscope.</b>—A polariscope for the examination of
+solutions of sugar consists essentially of a prism for polarizing
+the light, called a nicol, a tube of definite length for holding the
+sugar solution, a second nicol made movable on its axis for adjustment
+to the degree of rotation and a graduated arc for measuring it.
+Instead of having the second nicol movable, many instruments have an
+adjusting wedge of quartz of opposite polarizing power to the sugar,
+by means of which the displacement produced on the polarized plane is
+corrected. A graduated scale and vernier serve to measure the movement
+of the wedges and give in certain conditions the desired reading of
+the percentage of sugar present. Among the multitude of instruments
+which have been devised for analytical purposes, only three will be
+found in common use, and the scope of this volume will not allow space
+for a description of a greater number. For a practical discussion
+of the principles of polarization and their application to optical
+saccharimetry, the reader may conveniently refer to the excellent
+manuals of Sidersky, Tucker, Landolt, and Wiechmann.<a id="FNanchor_37" href="#Footnote_37" class="fnanchor">[37]</a></p>
+
+<p><b>64. Kinds of Polariscopes.</b>—The simplest form of a polarizing
+apparatus consists of two nicol prisms, one of which, <i>viz.</i>, the
+analyzer, is capable of rotation about its long axis. The prolongation
+of this axis is continuous with that of the other prism, <i>viz.</i>,
+the polarizer. The two prisms are sufficiently removed from each other
+to allow of the interposition of the polarizing body whose rotatory
+power is to be measured.
+<span class="pagenum"><a id="Page_81"></a>[Pg 81]</span></p>
+
+<p>For purposes of description three kinds of polarimeters may be
+mentioned.</p>
+
+<p>1. <i>Instruments in which the deviation of the plane of polarization
+is measured by turning the analyzer about its axis.</i></p>
+
+<p>Instruments of this kind conform to the simple type first mentioned,
+and are <i>coeteris paribus</i> the best. The Laurent, Wild,
+Landolt-Lippich, etc., belong to this class.</p>
+
+<p>2. <i>Instruments in which both nicols are fixed and the direction of
+the plane of polarized light corrected by the interposition of a wedge
+of a solid polarizing body.</i></p>
+
+<p>Belonging to this class are the apparatus of Soleil, Duboscq,
+Scheibler, and the compensating apparatus of Schmidt and Haensch.</p>
+
+<p>3. <i>Apparatus in which the analyzer is set at a constant angle with
+the polarizer, and the compensation secured by varying the length or
+concentration of the interposed polarizing liquid.</i></p>
+
+<p>The apparatus of Trannin belongs to this class.</p>
+
+<p><b>65. Appearance of Field of Vision.</b>—Polarimeters are also
+classified in respect of the appearance of the field of vision.</p>
+
+<p>1. <i>Tint Instruments.</i>—The field of vision in these instruments
+in every position of the nicols, except that on which the plane of
+vibration of the polarized light is coincident with the three principal
+sections, is composed of two semi-disks of different colors.</p>
+
+<p>2. <i>Shadow Instruments.</i>—The field of vision in this class of
+polarimeters in all except neutral positions, is composed of two
+semi-disks, one dark and one yellow. As the neutral position is
+approximated the two disks gradually assume a light yellow color, and
+when neutrality is reached they appear to be equally colored.</p>
+
+<p>The Laurent, Schmidt and Haensch shadow and Landolt-Lippich
+instruments, are of this class.</p>
+
+<p>3. <i>Striated Instruments.</i>—In this class the field of vision is
+striated. The lines may be tinted as in Wild’s polaristrobometer or
+black, as in the Duboscq and Trannin instruments. The neutral position
+is indicated either by the disappearance of the striae (Wild) or by the
+phenomenon of their becoming continuous. (Duboscq, Trannin.)
+<span class="pagenum"><a id="Page_82"></a>[Pg 82]</span></p>
+
+<p><b>66. Character of Light Used.</b>—Polariscopes may be further
+divided into two classes, based on the kind of light employed.</p>
+
+<p>1. <i>Instruments which Use Ordinary White Light.</i>—(Oil lamp, etc.)
+Scheibler, Schmidt and Haensch.</p>
+
+<p>2. <i>Instruments Employing Monochromatic Light.</i>—(Sodium flame,
+etc.) Laurent, Landolt-Lippich, etc.</p>
+
+<p><b>67. Interchangeable Instruments.</b>—Some of the instruments in
+common use are arranged to be used either with ordinary lamp or gas
+light, or with a monochromatic flame. Laurent’s polarimeter is one of
+this kind. The compensating instruments also may have the field of
+vision arranged for tints or shadows. Theoretically the best instrument
+would be one in which the light is purely monochromatic, the field of
+vision a shadow, and the compensation secured by the rotation of the
+second nicol.</p>
+
+<p>The accuracy of an instrument depends, however, on the skill and care
+with which it is constructed and used. With quartz wedges properly
+ground and mounted, and with ordinary white light, polariscopes may be
+obtained which give readings as accurate as can be desired.</p>
+
+<p>Since many persons are more or less affected with color-blindness, the
+shadow are to be preferred to the tint fields of vision.</p>
+
+<p>For practical use in sugar analysis the white light is much more
+convenient than the monochromatic light.</p>
+
+<p>For purposes of general investigation the polarimeters built on
+the model of the laurent are to be preferred to all others. Such
+instruments are not only provided with a scale which shows the
+percentage of sucrose in a solution, but also with a scale and vernier
+by means of which the angular rotation which the plane of vibration has
+suffered, can be accurately measured in more than one-quarter of the circle.</p>
+
+<h3>DESCRIPTION OF POLARIZING INSTRUMENTS.</h3>
+
+<p><b>68. Rotation Instruments.</b>—This instrument has already been
+described as one in which the extent of deviation in the plane of
+polarized light caused by the intervention of an optically active
+substance is measured by rotating one of the nicols about its axis and
+measuring the degree of this rotation by a vernier on a graduated arc.
+<span class="pagenum"><a id="Page_83"></a>[Pg 83]</span></p>
+
+<p>In Germany these instruments are called <i>polaristrobometers</i>,
+and in France <i>polarimètrés</i>. In England and this country the
+term <i>polariscope</i> or <i>polarimeter</i> is applied without
+discrimination to all kinds of optical saccharimeters.</p>
+
+<p>The polariscope of Mitscherlich was one of the earliest in use. It has
+now been entirely superseded by more modern and accurate instruments.</p>
+
+<p><b>69. The Laurent Instrument.</b>—A polariscope adapted by Laurent
+to the use of monochromatic yellow light is almost exclusively used in
+France and to a considerable extent in this country. In case a worker
+is confined to the use of a single instrument, the one just mentioned
+is to be recommended as the best suited to general work. It has the
+second nicol, called the analyzer, movable and the degree of rotation
+produced is secured in angular terms directly on a divided circle. The
+scale is graduated both in angular measurements and in per cents of
+sugar for a definite degree of concentration of the solution and length
+of observation tube. The normal solution in the laurent instrument
+contains 16.19 grams of pure sugar in 100 true cubic centimeters, and
+the length of the observation tube is 200 millimeters. Both the angular
+rotation and the direct percentage of sugar can be read at the same
+time. Great accuracy can be secured by making the readings in each
+of the four quadrants. The light is rendered yellow monochromatic by
+bringing into the flames of a double bunsen, spoons made of platinum
+wire, which carry fragments of fused sodium chlorid.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_33" src="images/fig33.jpg" alt="" width="500" height="558" >
+    <p class="center spb1">Figure 33. Laurent Lamp.</p>
+</div>
+
+<p><b>70. The Laurent Burner.</b>—The theory of the illumination of the
+laurent burner is illustrated by the accompanying <a href="#FIG_33">Fig. 33</a>.
+The lamp consists essentially of two bunsens, surmounted by a chimney.<a id="FNanchor_38" href="#Footnote_38" class="fnanchor">[38]</a>
+A curved spoon made of platinum gauze serves to hold the fused particles
+<span class="pagenum"><a id="Page_84"></a>[Pg 84]</span>
+of sodium chlorid which are used to produce the yellow light. The spoon
+is shown at G, held by the arm F, fastened by the key P. The interior
+intense flame B B is surrounded by an exterior less highly colored
+flame A A. It is important that the optical axis of the polariscope
+be directed accurately upon the disk B, which is the most intense
+part of the illumination. The point of the spoon carrying the salt
+should be coincident with the prolongation of the lamp TT, so that it
+just strikes the edge of the blue flame. Care should be taken not to
+press the spoons into the interior of the flame as by so doing the
+intensity of the illumination is very much diminished. Great care must
+be observed in the position of the spoon G, and the platinum arm F
+being flexible, the operator with a little patience, will be enabled
+to properly place the spoon by bending it. Moreover, if the spoon be
+pressed too far into the flame, the melted particles of salt collecting
+in the bottom of G may drop into the lamp and occlude the orifices
+through which the gas enters. The light of the yellow flame produced by
+the lamp may be further purified by passing through a prism filled with
+a solution of potassium dichromate, or better, a homogeneous disk cut
+from a crystal of that salt.</p>
+
+<p>Since the flame produced by the above device is not perfectly constant,
+being more intense at the moment of introducing a fresh portion of
+the fused salt, the author has used a lamp designed to furnish an
+absolutely constant flame.<a id="FNanchor_39" href="#Footnote_39" class="fnanchor">[39]</a>
+This device which is shown in <a href="#FIG_34">Fig. 34</a>, is
+based on the principle of adding constantly a fresh portion of the
+salt to the flame. The flame is thus kept perfectly uniform in its
+intensity.</p>
+
+<p>The lamp consists essentially of two wheels with platinum gauze
+perimeters and platinum wire spokes, driven by a clock-work D, and
+mounted by the supports AAʹ as shown in the <a href="#FIG_34">figure</a>.
+The sodium salt, chlorid or bromid, in dilute solution, is placed in the porcelain
+crucibles F, supported by BBʹ as indicated in the figure, to such a
+depth that the rims of the platinum wheels dip beneath the surface as
+they revolve. The salt is volatilized by the lamp E. By means of the
+crossed bands the wheels are made to revolve in opposite directions as
+indicated by the arrows. The solution of the salt which is taken up by
+<span class="pagenum"><a id="Page_85"></a>[Pg 85]</span>
+the platinum net-work of the rim of the wheel, thus has time to become
+perfectly dry before it enters the flame and the sputtering which
+a moist salt would produce is avoided. At every instant, by this
+arrangement, a minute fresh portion of salt is introduced into the
+flame with the result of making a perfectly uniform light which can
+be used for hours without any perceptible variation. The mechanism of
+the apparatus is so simple that no further description is necessary.
+The polariscope should be so directed toward the flame as to bring
+into the field of vision its most luminous part. The platinum wheels
+are adjustable and should be so arranged as to produce between them an
+unbroken yellow flame. The wheels are eight centimeters in diameter and
+are driven at a rate to make one revolution in from six to ten minutes.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_34" src="images/fig34.jpg" alt="" width="600" height="487" >
+    <p class="center spb1">Figure 34. Lamp for Producing Constant<br> Monochromatic Flame.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_86"></a>[Pg 86]</span>
+<b>71. Construction of Laurent’s Apparatus.</b>—The shadow polariscope
+invented by Laurent is constructed as follows: The polarizer is a
+special nicol which is not fixed in its position, but is so arranged
+as to be turned through a small arc about its axis. By this device,
+the quantity of light passing through it can be regulated, and the
+apparatus is thus useful with colored solutions which are not easily
+cleared by any of the common bleaching agents. The greater the quantity
+of light admitted, however, the less delicate is the reading of the
+shadow produced. The plane of polarized light emergent from this prism,
+falls on a disk of glass half covered by a thin lamina of quartz which
+thus divides the field of vision into halves. It is this semi-disk of
+quartz which is the distinguishing feature of the apparatus.<a id="FNanchor_40" href="#Footnote_40" class="fnanchor">[40]</a>
+The polarized light thus passes without hindrance the half field of vision
+which is covered by the glass only, but can not pass the quartz plate
+unless its axis is set in a certain way. The field of vision may be
+thus half dark, or both halves may be equally illuminated or equally
+dark according to the position of the nicol analyzer which is freely
+movable about its axis and carries a vernier and reading glass over
+a graduated circle. The field of vision in the laurent may have any
+of the following forms.<a id="FNanchor_41" href="#Footnote_41" class="fnanchor">[41]</a>
+Let the polarizer be first so adjusted that the plane of polarization
+of the transmitted pencil of light is parallel to the axis of the plate
+lying in the direction A B. The two halves of the field of vision will
+then appear equally illuminated in every position of the analyzer. But
+if the polarizing nicol be inclined to AB at an angle a, the plane of
+polarization of the rays passing through the quartz plate will undergo
+deviation through an equal angle in the opposite direction.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_35" src="images/fig35.jpg" alt="" width="600" height="188" >
+    <p class="center spb1">Figure 35. Field of Vision of a Laurent Polariscope.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_87"></a>[Pg 87]</span>
+It happens from this, that when in the uncovered half of the field, the
+plane of polarization has the direction AC, in the other half it will
+have the direction ACʹ. When the analyzer is rotated, if its plane of
+polarization lie in the direction cc, the rays polarized parallel to AC
+will be completely extinguished and the corresponding half of the field
+will be dark. The opposite happens when the plane of polarization lies
+in the direction of cʹcʹ. When one-half of the field is thus obscured,
+the other suffers only a partial diminution in the intensity of its
+illumination. When the middle position bb is reached in the rotation of
+the analyzer, the illumination of the two halves is uniform, and this
+is the point at which the zero of the scale is reached. The slightest
+rotation of the analyzer to the right or left of this neutral point
+will cause a shadow to appear on one of the halves of the field, which
+by an oscillatory movement of the analyzer, seems to leap from side to
+side. The smaller the angle <i>a</i> or BAC, the more delicate will be
+the shading and the more accurate the observation. This angle being
+adjustable by the mechanism already described, should be made as small
+as will permit the admission of the quantity of light requisite for
+accurate observation.</p>
+
+<p>The various pieces composing the polariscope are arranged in the
+following positions, beginning on the right of <a href="#FIG_36">Fig. 36</a>,
+and passing to the left, where the observer is seated.<a id="FNanchor_42" href="#Footnote_42" class="fnanchor">[42]</a></p>
+
+<p>1. The lamp VV, TT, AA, or the wheel burner:</p>
+
+<p>2. The lens B for condensing the rays and rendering them parallel:</p>
+
+<p>3. The tube I, blackened inside to carry the lens:</p>
+
+<p>4. A thin lamina E, cut from a crystal of potassium bichromate, serving
+to render the sodium light more monochromatic: When the saccharine
+liquids under examination are colored the crystal of bichromate is
+removed before the observation is made.</p>
+
+<p>5. The polarizer R, which is rotatable through a small angle by the
+lever K:</p>
+
+<p>6. The lever JK for rotating the tube containing the polarizer: This is
+operated by the rod X extending to the left.</p>
+
+<p>7. Diaphragm D, half covered with a lamina of quartz.
+<span class="pagenum"><a id="Page_88"></a>[Pg 88]</span></p>
+
+<p>8. Trough L for holding the observation tube: In the large instrument
+shown in the <a href="#FIG_36">figure</a>, it is more than half a meter in
+length and arranged to hold an observation tube 500 millimeters long.</p>
+
+<p>9. Disk C, carrying divided circle and arbitrary sugar scale:</p>
+
+<p>10. Mirror M, to throw the light of the lamp on the vernier of the scale:</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_36" src="images/fig36.jpg" alt="" width="600" height="367" >
+    <p class="center spb1">Figure 36. Laurent Polariscope.</p>
+</div>
+
+<p>11. Reading glass N, carried on the same radius as the mirror and used
+to magnify and read the scale:</p>
+
+<p>12. Device F, to regulate the zero of the instrument:</p>
+
+<p>13. Tube H, carrying a nicol analyzer and ocular O for defining the
+field of vision: This tube is rotated by the radial arm G, carrying the
+mirror and reading glass.</p>
+
+<p><b>72 Manipulation.</b>—The lamp having been adjusted, the instrument,
+in a dark room, is so directed that the most luminous spot of the flame
+is in the line of vision. An observation tube filled with water is
+placed in the trough and the zero of the vernier is placed accurately
+on the zero of the scale. The even tint of the field of vision is then
+secured by adjusting the apparatus by the device number 12.</p>
+
+<p><b>73 The Soleil-Ventzke Polariscope.</b>—A form of polariscope giving
+a colored field of vision was in use in this country almost exclusively
+until within ten years, and is still largely employed. There are many
+<span class="pagenum"><a id="Page_89"></a>[Pg 89]</span>
+forms of tint instruments, but the one almost exclusively used here
+is that mentioned. A full description of their construction and
+manipulation is given by Tucker.<a id="FNanchor_43" href="#Footnote_43" class="fnanchor">[43]</a>
+By the introduction of a third rotating nicol in front of the lens
+next to the lamp, the sensitive tint at which the reading is made
+can be kept at a maximum delicacy. These instruments are capable of
+rendering very reliable service, especially in the hands of those who
+have a delicate perception of color. They are inferior, however, to the
+shadow instruments in delicacy, and are more trying to the eye of the
+observer. The shadow instruments therefore, especially those making
+use of an ordinary kerosene lamp, have practically driven the tint
+polariscopes out of use.</p>
+
+<p>The general arrangement of a tint instrument as modified by Scheibler
+is shown in <a href="#FIG_37">Fig. 37</a>.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_37" src="images/fig37.jpg" alt="" width="600" height="289" >
+    <p class="center spb1">Figure 37. Tint Polariscope.</p>
+</div>
+
+<p>Beginning on the right of the figures, its optical parts are as
+follows: A is a nicol which, with the quartz plate B, forms the
+apparatus for producing the light rose neutral tint. The proper
+degree of rotation of these two parts is secured by means of the
+button L attached to the rod carrying the ratchet wheel as shown. The
+polarizing nicol is at C, and D is a quartz disk, one-half of which is
+right-handed and the other left-handed. At G is another quartz plate
+belonging to the analyzing part of the apparatus. This, together with
+the fixed quartz wedge F, and the movable quartz wedge E, constitute
+the compensating apparatus of the instrument whereby the deviation
+produced in the plane of polarized light by the solution in the tube is
+restored.</p>
+
+<p>Next to the compensating apparatus is the analyzing nicol which in this
+<span class="pagenum"><a id="Page_90"></a>[Pg 90]</span>
+instrument is fixed in a certain place, <i>viz.</i>, the zero of the
+scale. The analyzer and the telescope for observing the field of vision
+are carried in the tube HJ. The movable quartz wedge has a scale which
+is read with a telescope K, provided with a mirror inclined at an angle
+of 45°, just over the scale and serving to illuminate it. The quartz
+wedges are also provided with a movement by which the zero point of
+the scale can be adjusted. A kerosene lamp with two flat wicks is the
+best source of illumination and the instrument should be used in a dark
+room and the light of the lamp, save that which passes through the
+polariscope, be suppressed by a shade. The sensitive or transition tint
+is produced by that position of the regulating apparatus which gives
+a field of view of such a nature that a given small movement of the
+quartz compensating wedge gives the greatest contrast in color between
+the halves of the field of vision. For most eyes a faint rose-purple
+tint, as nearly colorless as possible, possesses this quality. A slight
+movement of the quartz wedge by means of the screw head M will, with
+this tint, produce on one side a faint green and on the other a pink
+color, which are in strong contrast. The neutral point is reached by so
+adjusting the quartz wedge as to give to both halves of the field the
+same faint rose-purple tint.</p>
+
+<p><b>74. The Shadow Polariscope for Lamp Light.</b>—This form of
+instrument is now in general use for saccharimetric purposes. It
+possesses on the one hand, the advantages of those instruments using
+monochromatic light, and on the other, the ease of manipulation
+possessed by the tint polariscopes. It differs from the tint instrument
+in dispensing with the nicol and quartz plate used to regulate
+the sensitive tint, and in having its polarizing nicol peculiarly
+constructed in harmony with the optical principles of the jellet-corny
+prism. The more improved forms of the apparatus have a double quartz
+wedge compensation. The two wedges are of opposite optical properties,
+and serve to make the observations more accurate by mutual correction.
+The optical arrangement of the different parts of such a polariscope is
+shown in the following <a href="#FIG_38">figure</a>.</p>
+
+<p>The lenses for concentrating the rays of light and rendering them
+<span class="pagenum"><a id="Page_91"></a>[Pg 91]</span>
+parallel are contained in the tube N. At O is placed the modified
+polarizing nicol. The two compensating quartz wedges are moved by the
+milled screw-heads EG. The rest of the optical apparatus is arranged
+as described under the tint polariscope. For practical purposes, only
+one of the wedges is employed, but for all accurate work the readings
+should be made with both wedges and thus every possible source of error
+eliminated.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_38" src="images/fig38.jpg" alt="" width="600" height="310" >
+    <p class="center spb1">Figure 38. Double Compensating Shadow Polariscope.</p>
+</div>
+
+<p id="P_75"><b>75. The Triple Shadow Instrument.</b>—When properly made, all
+the instruments which have been mentioned, are capable of giving
+accurate results if used in harmony with the directions given. In the
+use of polariscopes having colored fields of vision a delicate sense
+of distinguishing between related tints is necessary to good work.
+Color-blind observers could not successfully use such apparatus. In
+the shadow instruments it is only necessary to distinguish between the
+halves of a field of vision unequally illuminated and to reduce this
+inequality to zero. A neutral field is thus secured of one intensity
+of illumination and of only one color, usually yellow. Such a field of
+vision permits of the easy discrimination between the intensity of the
+coloration of its two halves, and is consequently not trying to the eye
+of the observer, and allows of great accuracy of discrimination. This
+field of vision has lately been still further improved by dividing it
+into three parts instead of two. An instrument of this kind, <a href="#FIG_39">Fig. 39</a>,
+in use in this laboratory, permits a delicacy of reading not possessed
+by any other instrument used for sugar analysis, and approaching that
+<span class="pagenum"><a id="Page_92"></a>[Pg 92]</span>
+of the standard Landolt-Lippich apparatus, used by us for research
+work and for determining the rotation of quartz plates and testing the
+accuracy of other polariscopes.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_39" src="images/fig39.jpg" alt="" width="600" height="259" >
+    <p class="center spb1">Figure 39. Triple Shadow Polariscope.</p>
+</div>
+
+<p>The triple shadow is secured by interposing in front of the polarizing
+nicol two small nicols as indicated in <a href="#FIG_40">Fig. 40</a>.
+The end views in different positions of the polarizer are shown in the
+lower part of the diagrams.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_40" src="images/fig40.jpg" alt="" width="500" height="458" >
+    <p class="center spb1">Figure 40. Apparatus for Producing a Triple Shadow.</p>
+</div>
+
+<p>Instead of the comparison of the intensity of the illumination being
+made on the halves of the field of vision it is made by comparing
+the segments of the halves with a central band, which also changes in
+intensity synchronously with the two segments, but in an opposite direction.</p>
+
+<h3>THE ANALYTICAL PROCESS.</h3>
+
+<p><b>76. General Principles.</b>—Having described the instruments
+chiefly employed in the optical examination of sugar solutions, the next
+<span class="pagenum"><a id="Page_93"></a>[Pg 93]</span>
+step is to apply them to the analytical work. A common set of
+directions for use will be found applicable to all instruments
+with such modifications only as are required by peculiarities of
+construction. With the best made instruments it is always advisable
+to have some method of controlling the accuracy of the observation.
+The simplest way of doing this is to test the apparatus by standard
+quartz plates. These plates are made from right-handed polarizing
+quartz crystal ground into plates of definite thickness and accurately
+tested by standard instruments. Theoretically such quartz plates
+deflect the plane of polarized light in a degree proportionate to
+their thickness, but practically some small deviations from the rule
+are found. With a source of light of the same tint, and at a constant
+temperature, such plates become a safe test for the accuracy of the
+graduation of polariscopes. They are more convenient for use than pure
+sugar solutions of known strength which are the final standards in
+all disputed cases. These quartz plates are conveniently mounted in
+tubes of the same size as those holding the sugar solution, and thus
+fit accurately into the trough of the polariscope, the optical axis
+of which passes through their center. The quartz plate when used for
+setting the scale of a polariscope should be placed always in the same
+position. In some plates slight differences of reading may be noticed
+on rotating the tubes holding them. Theoretically, such differences
+should not exist, but in practice they are sometimes found. The temperature
+of observation should also be noted, and if not that at which the value
+of the plate was fixed a proper correction should be made.</p>
+
+<p><b>77. Setting the Polariscope.</b>—While mention has been made of
+several forms of apparatus in the preceding paragraphs, those in common
+use are limited to a very small number. In this country quite a number
+of color instruments may still be found, together with a few laurents,
+and a constantly increasing number of shadow instruments for use with
+lamp light. The following description of setting the polariscope is
+especially adapted to the last named instrument, but the principles of
+adjustment are equally applicable to all.</p>
+
+<p>The scale of the instrument is first so adjusted by means of the
+adjusting screws provided with each instrument, as to bring the zero of
+<span class="pagenum"><a id="Page_94"></a>[Pg 94]</span>
+the vernier and that of the scale exactly together. The telescope or
+ocular is then adjusted until the sharp line separating the halves of
+the field of vision is brought into focus. This being accomplished an
+observation tube filled with pure water is placed in the apparatus
+and the telescope again adjusted to bring the dividing line of the
+field into focus. The beginner especially, should repeatedly study
+this adjustment and be impressed with the fact that only in a sharply
+defined field are practical observations of any worth. The importance
+of having all the lenses perfect and all the cover glasses without a
+flaw may be fully appreciated when it is remembered that the polarized
+ray, already deprived of half its original luminous power, must pass
+through several centimeters of crystallized calcium carbonate, and
+half a dozen disks of glass and quartz, and as many lenses before
+reaching the eye of the observer. Only with the greatest care and
+neatness is it possible to secure the required degree of illumination.
+The zero point having been well studied and accurately adjusted, the
+scale of the instrument may be tried with a series of quartz plates of
+known polarizing power at the temperature of the observation. In the
+apparatus with double quartz wedge compensation, it will be noticed
+that the marks on one scale are black and on the other red. The
+black is the working and the red the control scale. To operate this
+instrument, the red scale is placed exactly at the zero point. The
+black scale is also placed at zero, and if the field of vision is not
+neutral, it is made so by the micrometer screw with which the black
+scale is provided. In a right-handed solution, the red scale is left
+at zero and the black one moved to the right until neutrality in the
+field of vision is reached and the reading is taken. The observation
+tube containing the sugar solution is taken out and the red scale
+moved until the field of vision is again neutral and the reading of
+the red scale taken. The two readings should agree. Any failure in the
+agreement shows some fault either in adjusting the apparatus or in its
+construction, or some error in manipulation.</p>
+
+<p>The double compensating shadow instruments are more readily tested
+for accuracy in all parts of the scale than those of any other
+<span class="pagenum"><a id="Page_95"></a>[Pg 95]</span>
+construction. The two compensating wedges are cut with the greatest
+care, one from a left-handed and the other from a right-handed
+perfectly homogeneous quartz crystal. Since faults in these wedges are
+due either to lack of parallelism of surface, or of perpendicularity
+to the optical axis of the crystal, and since these faults of
+crystallization or construction must be in a very limited degree common
+they would not coincide once in many thousand times in the two wedges.
+This is easily shown by the theory of probabilities. If, therefore, the
+two readings made at any point, should not agree, it must be due either
+to a fault in one of the wedges, or to a fault in reading or a lack of
+adjustment, as has been mentioned. In such cases the readings should be
+retaken and the errors are usually easily discovered.</p>
+
+<p><b>78. Control Observation Tube.</b>—Instead of using quartz plates of
+known values for testing the accuracy of the scale, an observation tube
+may be used, the length of which can be varied at the pleasure of the observer.</p>
+
+<p>The construction of a tube of this kind is shown in <a href="#FIG_40">Fig. 40</a>.
+The tube B is movable telescopically in A by means of the ratchet wheel
+shown. It is closed at D water-tight by a glass disk. The tube B fits
+as accurately into A as is possible to permit of free movement, and
+any liquid which may infilter between its outer surface and the inner
+surface of A is prevented from gaining exit by the washer C, which
+fits both tubes water-tight. The ratchet which moves B in A carries
+a millimeter scale and vernier N whereby the exact thickness of the
+liquid solution between the surfaces of the glass disks D and E can be
+always determined.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_41" src="images/fig41.jpg" alt="" width="600" height="313" >
+    <p class="center spb1">Figure 41. Control Observation Tube.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_96"></a>[Pg 96]</span>
+By this device the length of liquid under observation can be accurately
+read to a tenth of a millimeter. The cover glass E is held in position
+by any one of the devices in common use for this purpose in the case in
+question, by a bayonet fastening. The funnel T, communicating directly
+with the interior of A, serves to hold the solution, there being always
+enough of it to fill the tube when D is removed to the maximum distance
+from C, which is usually a little more than 200 millimeters.</p>
+
+<p>Let the control tube be adjusted to 200 millimeters and filled with a
+solution of pure sugar, which reads 100 per cent or degrees in a 200
+millimeter tube. Since the degree of rotation is, other things being
+equal, proportional to the length of the column of polarizing solution,
+it follows that if the tube B be moved inward until the distance
+between D and C is 100 millimeters, the scale should read 50° or per
+cent. By adjusting the length of the distance between B and C it is
+easily seen that every part of the scale can be accurately tested.</p>
+
+<p>The tube should be filled by removing the funnel and closing the
+orifice with a screw cap which comes with the apparatus. The cap E
+is then removed and the tube filled in the ordinary manner. This
+precaution is practiced to avoid carrying air bubbles into the tube
+when filled directly through the funnel. With a little care, however,
+this danger may be avoided, or should air bubbles enter they can be
+easily removed by inclining the tube.</p>
+
+<p>In case the solution used be not strictly pure it may still be employed
+for testing the scale. Suppose, for instance, that a solution made up
+in the usual way, has been made from a sample containing only 99.4 per
+cent of sugar. Then in order to have this solution read 100° on the scale
+the tube should be set at 201.2 millimeters, according to the formula</p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">&nbsp;</td>
+      <td class="tdc bb">200 × 100</td>
+      <td class="tdl_wsp" rowspan="2">= 201.2.</td>
+   </tr><tr>
+      <td class="tdc">99.4</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>By a similar calculation the position of the tube for reading any
+desired degree on the scale can be determined. The importance of
+controlling all parts of the scale in compensating instruments is
+emphasized by the fact that a variation of only 0.016 millimeter in the
+thickness of the compensating wedge will cause a change of one degree
+in the reading of the instrument.</p>
+
+<p><b>79. Setting the Polariscope with Quartz Plates.</b>—Pure sugar is
+<span class="pagenum"><a id="Page_97"></a>[Pg 97]</span>
+not always at the command of the analyst, and it is more convenient
+practically to adjust the instrument by means of quartz plates, the
+sugar values of which have been previously tested for the character
+of the light used. Assuming the homogeneity of a plate of quartz, the
+degree of deflection which it imparts to a plane of polarized light
+depends on the quality of the light, the thickness of the plate, and
+the temperature.</p>
+
+<p>In respect of the quality of light, red polarized rays are least, and
+violet most deflected. The degree of rotation produced with any ray,
+at a given temperature, is directly proportional to the thickness of
+the plate. Temperature affects the rotating power of a quartz plate
+in a degree highly significant from a scientific point of view and
+not wholly negligible for practical purposes. The rotating power of a
+quartz plate increases with the temperature and the variation may be
+determined by the formula given below:<a id="FNanchor_44" href="#Footnote_44" class="fnanchor">[44]</a></p>
+
+<p>The formula is applicable for temperatures between 0° and 100°. Its
+values are expressed in degrees of angular measure which can be
+converted into degrees of the sugar scale by appropriate factors:</p>
+
+<p class="fs_110"><i>Formula.— a</i>ᵗ = <i>a</i>°(1 + 0.000146<i>t</i>);</p>
+
+<p class="no-indent">in which <i>a</i>° = polarization in angular degrees at 0°,
+<i>t</i> the temperature of observation and <i>a</i>ᵗ the rotation desired.</p>
+
+<p><i>Example.</i>—A quartz plate which has an angular rotation of 33° at
+0° will have a rotation at 20° of 33°.09834.</p>
+
+<p class="fs_110"><i>a</i>ᵗ = 33(1 + 0.000146 × 20) = 33.09834.</p>
+
+<p>Since in instruments using the ventzke scale one degree of the sugar
+scale is equal to 0.3467 degree angular measure, the sugar value of the
+quartz plate mentioned is equal to 95.47 percent; 33.09834 ÷ 0.3467 = 95.47.</p>
+
+<p>The sugar value of this plate at 0° is 95.18 per cent; 33 ÷ 0.3467 = 95.18.</p>
+
+<p><b>80. Tables for Correcting Quartz Plates.</b>—Instead of calculating
+the variation in quartz plates for each temperature of observation, it
+is recommended by the Bureau of Internal Revenue of the Treasury, to
+use control quartz plates the values of which at any given temperature,
+are found on a card which accompanies each one.<a id="FNanchor_45" href="#Footnote_45" class="fnanchor">[45]</a>
+The variations given, are from temperatures between 10° and 35°. Three control
+<span class="pagenum"><a id="Page_98"></a>[Pg 98]</span>
+plates are provided with each instrument used by the Bureau, for polarimetric
+work in the custom houses, or in ascertaining bounties to be paid on
+the production of domestic sugars. For example, the case of a sugar
+which polarizes 80°.5 may be cited. One of the control plates nearest
+to this number, is found to have at the temperature of observation, a
+polarization of 91°.4, the reading being made in each case at 25°. On
+consulting the card which accompanies the control plate, it is seen
+that its value at the temperature mentioned, is 91°.7. The reading of
+the instrument is therefore too low by three-tenths of a degree, and
+this quantity should be added to the observed polarization, making it
+80°.8. In this method of correcting the reading for temperature, it is
+assumed that the compensating wedges of the instrument, are free of
+error at the points of observation. The plates used for the purpose
+above, are all standardized in the office of weights and measures of
+the Coast and Geodetic Survey, before delivery to the analysts.</p>
+
+<p><b>81. Applicability of Quartz Plates.</b>—Quartz plates which are
+correctly set for one instrument or kind of light, should be equally
+accurate for the sugar scales of all instruments, using the same sugar
+factor. In other words a quartz plate which reads 99° on a scheibler
+color polariscope, should give the same reading on the sugar scale of a
+shadow compensating or a monochromatic direct reading apparatus using
+26.048 grams of sugar.</p>
+
+<p>The most useful quartz plates for sugar analysis, are those which give
+the readings at points between 80° and 96°, which cover the limits of
+ordinary commercial sugars. For molasses the plates should read from
+45° to 55°. For sugar juices of the cane and beet, the most convenient
+graduation would be from 10° to 20°, but plates of this value would be
+too thin for practical work and are not in use. When quartz plates are
+to be used for control purposes, they should be purchased from reliable
+manufacturers, or better, tested directly against pure sugar solutions
+by the observer.</p>
+
+<p>In practice we have found quartz plates as a rule, true to their
+markings.</p>
+
+<p><b>82. The Sugar Flask.</b>—Sugar solutions are prepared for
+polarization in flasks graduated to hold fifty or one hundred cubic
+<span class="pagenum"><a id="Page_99"></a>[Pg 99]</span>
+centimeters. For scientific work a flask is marked to hold 100 grams of
+distilled water at 4°. The weights are all to be reduced to a vacuum
+standard. One flask having been marked in this way, others may be
+compared directly therewith by means of pure mercury. For this purpose
+the flasks must be perfectly dry and the mercury pure, leaving no stain
+on the sides of the flask. The glass must also be strong enough to
+undergo no change in shape from the weight of mercury used.</p>
+
+<p>For sugar work the true 100 gram flask is not usually employed, but
+one graduated by weighing at 17°.5. These flasks are graduated by
+first weighing them perfectly dry, filling with distilled water and
+again weighing fifty and fifty-five, or 100 and 110 grams of water at
+the temperature named. Since the volume of water at 17°.5 is greater
+than at 4° the sugar flask in ordinary use has a greater volume by
+about 0.25 cubic centimeter than the true flask. The observer should
+always secure a statement from the dealer in respect of the volume
+of the flask used in testing the scale of the polariscope purchased.
+In the graduation of a flask in true cubic centimeters, when brass
+weights are used it will be necessary to correct the weight of each
+gram of water by adding to it one milligram, which is almost exactly
+the weight of the volume of air displaced by one gram of water in the
+circumstances named. If the flask be first counterbalanced and it be
+desired to mark it at 100 cubic centimeters the sum of the weights
+placed in the opposite pan should be 100 - 0.100 = 99.900 grams. While
+this is not a rigidly exact correction it will be sufficient for all
+practical purposes. A liter of dry air weighs 1.29366 grams; and 100
+cubic centimeters of water would therefore displace 0.129 gram of air.
+But the brass weights also displace a volume of air which when deducted
+reduces the correction to be made for the water to nearly the one
+named. For convenience in inverting sugar solutions the flasks used in
+practical work are graduated at fifty and fifty-five and 100 and 110
+cubic centimeters respectively.</p>
+
+<p id="P_83"><b>83. Preparing Sugar Solutions for Polarization.</b>—If sugar
+samples were always pure the percentage of sugar in a given solution
+could be directly determined by immediate polarization. Such cases,
+<span class="pagenum"><a id="Page_100"></a>[Pg 100]</span>
+however, are rarely met in practice. In the majority of cases the
+sample is not only to be brought into solution but is also to be
+decolorized and rendered limpid by some one of the methods to be
+described. A perfectly limpid liquid is of the highest importance to
+secure correct observations. With a cloudy solution the field of vision
+is obscured, the dividing line of the two halves, or the double line
+in the triple field, becomes blurred or invisible and the intensity
+of illumination is diminished. A colored liquid which is bright is
+far more easy to polarize than a colorless liquid which is turbid. In
+fact, it is only rarely in sugar work that samples will be found which
+require any special decolorizing treatment other than that which is
+received in applying the reagents which serve to make the solutions
+limpid. In the following paragraphs the approved methods of clarifying
+sugar solutions preparatory to observation in the polariscope will be
+described.</p>
+
+<p id="P_84"><b>84. Alumina Cream.</b>—The hydrate of alumina, commonly known as
+alumina cream, is always to be preferred as a clarifying agent in all
+cases where it can be successfully applied.<a id="FNanchor_46" href="#Footnote_46" class="fnanchor">[46]</a>
+It is a substance that acts wholly in a mechanical way and therefore
+leaves the sugars in solution unchanged, carrying out only suspended
+matters. In the preparation of this reagent a solution of alum is
+treated with ammonia in slight excess, the aluminum hydroxid produced
+washed on a filter or by decantation until neutral in reaction. The
+hydroxid is suspended in pure water in proportions to produce a creamy
+liquid. Although apparently very bulky, the actual space occupied by
+the amount of dry hydroxid added in a few cubic centimeters is so small
+as to produce no disturbing effect of importance on the volume of the
+sugar solution. The cream thus prepared is shaken just before using and
+from one to five cubic centimeters of it, according to the degree of
+turbidity of the saccharine solution, are added before the volume in
+the flask is completed to the mark. After filling the flask to the mark
+the ball of the thumb is placed over the mouth and the contents well
+shaken and allowed to stand for a few moments before filtering.</p>
+
+<p>The alumina cream is well suited to use with solutions of commercial
+sugars of not too low a grade and of most honeys and high grade sirups.
+<span class="pagenum"><a id="Page_101"></a>[Pg 101]</span>
+It is usually not powerful enough to clarify beet and cane juices,
+molasses and massecuites.</p>
+
+<p><b>85. Basic Lead Acetate.</b>—A solution of basic lead acetate is an
+invaluable aid to the sugar analyst in the preparation of samples for
+polarimetric observation. It acts as a clarifying agent by throwing
+out of solution certain organic compounds and by uniting with the
+organic acids in solution forms an additional quantity of precipitate,
+and these precipitates act also mechanically in removing suspended
+matters from solution. The action of this reagent is therefore much
+more vigorous than that of alumina cream. Coloring matters are often
+precipitated and removed by treatment with lead acetate. It happens
+therefore that there are few samples of saccharine bodies whose
+solutions cannot be sufficiently clarified by lead acetate to permit of
+polarimetric observation.</p>
+
+<p>The reagent is most frequently employed of the following
+strength:<a id="FNanchor_47" href="#Footnote_47" class="fnanchor">[47]</a>
+Boil for half an hour in one and a half liters of water 464 grams of
+lead acetate and 264 grams of litharge with frequent stirring. When
+cool, dilute with water to two liters, allow to stand until clear, and
+decant the solution. The specific gravity of this solution is about 1.267.</p>
+
+<p>In a solution of basic lead acetate of unknown strength the percentage
+of lead acetate may be determined from its specific gravity by the
+following table:<a id="FNanchor_48" href="#Footnote_48" class="fnanchor">[48]</a></p>
+
+<p class="f120 spa1"><b><span class="smcap">Percentage of Lead Acetate
+Corresponding<br> to Different Specific Gravities at 15°.</span></b></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb">&nbsp; Specific &nbsp;<br>gravity.</th>
+      <th class="tdc bb">&nbsp; Percentage of &nbsp;<br> lead acetate.</th>
+      <th class="tdc bb">&nbsp; Specific &nbsp;<br>gravity.</th>
+      <th class="tdc bb">&nbsp; Percentage of &nbsp;<br> lead acetate.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">1.0127</td>
+      <td class="tdc">&#8199;2</td>
+      <td class="tdc">1.2040</td>
+      <td class="tdc">28</td>
+   </tr><tr>
+      <td class="tdc">1.0255</td>
+      <td class="tdc">&#8199;4</td>
+      <td class="tdc">1.2211</td>
+      <td class="tdc">30</td>
+   </tr><tr>
+      <td class="tdc">1.0386</td>
+      <td class="tdc">&#8199;6</td>
+      <td class="tdc">1.2395</td>
+      <td class="tdc">32</td>
+   </tr><tr>
+      <td class="tdc">1.0520</td>
+      <td class="tdc">&#8199;8</td>
+      <td class="tdc">1.2579</td>
+      <td class="tdc">34</td>
+   </tr><tr>
+      <td class="tdc">1.0654</td>
+      <td class="tdc">10</td>
+      <td class="tdc">1.2768</td>
+      <td class="tdc">36</td>
+   </tr><tr>
+      <td class="tdc">1.0796</td>
+      <td class="tdc">12</td>
+      <td class="tdc">1.2966</td>
+      <td class="tdc">38</td>
+   </tr><tr>
+      <td class="tdc">1.0939</td>
+      <td class="tdc">14</td>
+      <td class="tdc">1.3163</td>
+      <td class="tdc">40</td>
+   </tr><tr>
+      <td class="tdc">1.1084</td>
+      <td class="tdc">16</td>
+      <td class="tdc">1.3376</td>
+      <td class="tdc">42</td>
+   </tr><tr>
+      <td class="tdc">1.1234</td>
+      <td class="tdc">18</td>
+      <td class="tdc">1.3588</td>
+      <td class="tdc">44</td>
+   </tr><tr>
+      <td class="tdc">1.1384</td>
+      <td class="tdc">20</td>
+      <td class="tdc">1.3810</td>
+      <td class="tdc">46</td>
+   </tr><tr>
+      <td class="tdc">1.1544</td>
+      <td class="tdc">22</td>
+      <td class="tdc">1.4041</td>
+      <td class="tdc">48</td>
+   </tr><tr>
+      <td class="tdc">1.1704</td>
+      <td class="tdc">24</td>
+      <td class="tdc">1.4271</td>
+      <td class="tdc">50</td>
+   </tr><tr>
+      <td class="tdc">1.1869</td>
+      <td class="tdc">26</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p id="P_86"><span class="pagenum"><a id="Page_102"></a>[Pg 102]</span>
+<b>86. Errors Due to use of Lead Solutions.</b>—In the use of lead
+solutions there is danger of errors intruding into the results of
+the work. These errors are due to various sources. Lead subacetate
+solution, when used with low grade products, or sugar juices, or sirups
+from beets and canes, precipitates albuminous matters and also the
+organic acids present. The bulk occupied by these combined precipitates
+is often of considerable magnitude, so that on completing the volume in
+the flask the actual sugar solution present is less than indicated. The
+resulting condensation tends to give too high a polarimetric reading.
+With purer samples this error is of no consequence, but especially with
+low grade sirups and molasses it is a disturbing factor, which must be
+considered.</p>
+
+<p>One of the best methods of correcting it has been proposed by
+Scheibler.<a id="FNanchor_49" href="#Footnote_49" class="fnanchor">[49]</a>
+To 100 cubic centimeters of a solution of the sample,
+ten of lead solution are added, and after shaking and filtering
+the polarimetric reading is taken. Another quantity of 100 cubic
+centimeters of the solution with ten of lead is diluted to 220 cubic
+centimeters, shaken, filtered, and polarized. Double the second
+reading, subtract it from the first, multiply the difference by 2.2,
+and deduct the product from the first reading. The remainder is the
+correct polarization.</p>
+
+<p>The process just described is for the usual work with beet juices and
+sirups. For cane juices measured by the graduated pipette, hereafter to
+be described, and for weighed samples of molasses and massecuites, the
+following method of calculation is pursued.<a id="FNanchor_50" href="#Footnote_50" class="fnanchor">[50]</a>
+To the sample dissolved in water, add a measured portion of the lead
+subacetate solution, make its volume 100 cubic centimeters and observe
+the polarimetric reading. Prepare a second solution in the same way
+and make the volume double that of the first and again take the
+polarimetric reading. Multiply the second reading by two, subtract the
+product from the first reading and multiply the remainder by two, and
+subtract the product from the first reading.</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl_top" rowspan="5"><i>Example.</i>—</td>
+      <td class="tdl">First polarization</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdl_ws1">30.0</td>
+   </tr><tr>
+      <td class="tdl">Second polarization</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdl_ws1">14.9</td>
+   </tr><tr>
+      <td class="tdl">Then 30 - (2 × 14.9 = 29.8)</td>
+      <td class="tdl_wsp">=  &#8199;0.2</td>
+      <td class="tdc">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl_ws2">0.2 × 2</td>
+      <td class="tdl_wsp">=  &#8199;0.4</td>
+      <td class="tdc">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">and 30 - 0.4</td>
+      <td class="tdl_wsp">= &nbsp;29.6</td>
+      <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_103"></a>[Pg 103]</span>
+The corrected reading therefore shows that the sample contained 29.6
+per cent of sugar.</p>
+
+<p id="P_87"><b>87. Error Due to Action of Lead Subacetate on Levulose.</b>—In the
+use of lead subacetate solution not only is there danger of error due
+to the causes just described, but also to a more serious one, arising
+from the chemical interaction of the clarifying agent and levulose.<a id="FNanchor_51" href="#Footnote_51" class="fnanchor">[51]</a></p>
+
+<p>Lead subacetate forms a chemical union with levulose and the resulting
+compound has a different rotatory power from the left-handed sugar in
+an uncombined state. By adding a sufficient quantity of subacetate
+solution, the left-handed rotation of levulose may be greatly
+diminished if not entirely destroyed. In this case the dextrose, which
+with levulose forms inverted sugar, serves to increase the apparent
+right rotation due to the sucrose in solution. The reading of the
+scale is therefore higher than would be given by the sucrose alone.
+If the lead subacetate could be added in just the proportion to make
+the invert sugar neutral to polarized light, its use would render the
+analysis more accurate; but such a case could only arise accidentally.
+To correct the error, after clarification, the compound of levulose and
+lead may be decomposed by the addition of acetic acid according to the
+method of Spencer. In this case the true content of sucrose can only be
+obtained by the method of inversion proposed by Clerget, which will be
+described in another paragraph.</p>
+
+<p id="P_88"><b>88. Clarification with Mercuric Compounds.</b>—Where the disturbing
+bodies in a solution are chiefly of an albuminoid nature, one of the
+best methods of securing clarification is by the use of a solution
+containing an acid mercuric compound.<a id="FNanchor_52" href="#Footnote_52" class="fnanchor">[52]</a>
+In the case of milk this method is to be preferred to all others.
+Albuminoid bodies themselves, have the property of deflecting the plane
+of polarization, as a rule, to the left, and therefore, should be
+completely removed from solutions containing right-handed sugars such
+as lactose. For this purpose the mercuric compound is more efficient
+than any other. It is prepared and used as follows.<a id="FNanchor_53" href="#Footnote_53" class="fnanchor">[53]</a>
+Dissolve mercury in double its weight of strong nitric acid and dilute
+the solution with an equal volume of water. One cubic centimeter of
+this solution is sufficient to clarify fifty times its volume of milk.
+<span class="pagenum"><a id="Page_104"></a>[Pg 104]</span></p>
+
+<p><b>89. Decolorization by Means of Bone-Black.</b>—Where the means
+already described fail to make a solution sufficiently colorless to
+permit of the passage of a ray of polarized light, recourse should be
+had to a decolorizing agent. The most efficient of these is bone-black.
+For laboratory work it is finely ground and should be dry if added to
+an already measured solution. When moist it should be added to the
+flask before the volume is completed, and a correction made for the
+volume of the dry char employed. Bone-black has the power of absorbing
+a certain quantity of sugar, and for this reason as little of it
+should be employed as is sufficient to secure the end in view. If not
+more than one gram of the char be used for 100 cubic centimeters of
+solution, the error is not important commercially. The error may be
+avoided by placing the char on the filter and rejecting the first half
+of the filtered solution. The char becomes saturated with the first
+portion of the solution, and does not absorb any sugar from the second.
+This method, however, does not secure so complete a decolorization as
+is effected by adding the black directly to the solution and allowing
+to stand for some time with frequent shaking.</p>
+
+<p><b>90. Remarks on Analytical Process.</b>—Since large weights of sugar
+are taken for polarization, a balance which will weigh accurately to
+one milligram may be used. In commercial work the weighing is made in a
+counterpoised dish with a prominent lip, by means of which the sample
+can be directed into the mouth of the flask after partial solution.
+Where the air in the working room is still, an uncovered balance is
+most convenient. With a little practice the analyst will be able to
+dissolve and transfer the sample from the dish to the flask without
+danger of loss. The source of light used in polarizing should be in
+another room, and admitted by a circular opening in the partition. In a
+close polarizing room, which results from the darkening of the windows,
+the temperature will rapidly rise if a lamp be present, endangering
+notably the accuracy of the work, and also interfering with the comfort
+of the observer. The greatest neatness must be practiced in all stages
+of the work, and especially the trough of the polariscope must be kept
+from injury which may arise from the leaking of the observation tubes.
+<span class="pagenum"><a id="Page_105"></a>[Pg 105]</span>
+Dust and dirt of all kinds must be carefully excluded from the lenses,
+prisms, wedges and plates of the instrument.</p>
+
+<p id="P_91"><b>91. Determination of Sucrose by Inversion.</b>—In the foregoing
+paragraphs directions have been given for the estimation of sugar
+(sucrose) by its optical properties. It has been assumed so far, that
+no other disturbing bodies have been present, save those which could be
+removed by the clarifying agents described. The case is different when
+two or more sugars are present, each of which has a specific relation
+to polarized light. In such cases some method must be used for the
+optical determination of sucrose, which is independent of the influence
+of the other polarizing bodies, or else recourse must be had to other
+methods of analysis. The conversion of the sucrose present into invert
+sugar by the action of an acid or a ferment, affords an opportunity for
+the estimation of sucrose in mixed sugars, by purely optical methods.
+This process rests upon the principle that by the action of a dilute
+acid for a short time, or of a ferment for a long time, the sucrose
+is completely changed, while other sugars present are not sensibly
+affected. Neither of these assumptions is rigidly correct but each is
+practically applicable.</p>
+
+<p>The sucrose by this process of hydrolysis is converted into an equal
+mixture of levulose and dextrose. The former, at room temperatures, has
+the higher specific rotating power, and the deflection of the plane of
+polarization in a solution of inverted sugar is therefore to the left.
+The levorotatory power of invert sugar varies with the temperature,
+and this arises from the optical properties of the levulose. The
+influence of temperature on the rotating power of other sugars, is not
+imperceptible in all cases, but in practice is negligible.</p>
+
+<p>This method of analysis is invaluable in control work in factories,
+in the customs and in agricultural laboratories. Since the rotating
+power of levulose diminishes as the temperature rises, an accurate
+thermometric observation must accompany each polarimetric reading. At
+about 88° the rotatory powers of dextrose and levulose are equal, and a
+solution of pure invert sugar examined at that degree, is found to be
+neutral to polarized light.</p>
+
+<p id="P_92"><b>92. Clerget’s Method of Inversion.</b>—The classical method of
+<span class="pagenum"><a id="Page_106"></a>[Pg 106]</span>
+Clerget for the determination of cane sugar by double polarization
+before and after inversion, was first described in a memoir presented
+to the Society of Encouragement for National Industry on the 14th of
+October, 1846. The following description of the original method is
+taken from a reprint of the proceedings of that Society, dated Nov. 1846:</p>
+
+<p>Clerget points out first the observation of Mitscherlich regarding
+the influence of temperature on the rotatory power of invert sugar,
+and calls attention to the detailed experiments he has made which
+resulted in the determination of the laws of the variation. From these
+studies he was able to construct a table of corrections, applicable in
+the analysis of all saccharine substances in which the cane sugar is
+polarized before and after inversion. The basis of the law rests upon
+the observation that a solution of pure sugar, polarizing 100° on the
+sugar scale, before inversion, will polarize 44° to the left after
+inversion at a temperature of zero. The quantity of sugar operated upon
+by Clerget amounted to 16.471 grams in 100 cubic centimeters of liquid.
+On the instrument employed by him this quantity of sugar in 100 cubic
+centimeters gave a reading of 100° to the right on the sugar scale
+when contained in a tube twenty centimeters in length. The process of
+inversion carried on by Clerget is as follows:</p>
+
+<p>The sugar solution is placed in a flask, marked on the neck at 100
+and 110 cubic centimeters; or if smaller quantities are used, in a
+flask marked on the neck at fifty and fifty-five cubic centimeters.
+The flask is filled with the sugar solution to the first mark and then
+a sufficient quantity of strong hydrochloric acid added to bring the
+volume of the liquid to the second mark. The mouth of the flask is then
+closed with the thumb and its contents thoroughly mixed by shaking.
+A thermometer is placed in the flask which is set in a water-bath in
+such a way that the water comes just above the level of the liquid
+in the neck of the flask. The water is heated in such a manner as to
+bring the temperature of the contents of the flask, as determined
+by the thermometer, exactly to 68° and at such a rate as to require
+fifteen minutes to reach this result. At the end of fifteen minutes the
+<span class="pagenum"><a id="Page_107"></a>[Pg 107]</span>
+temperature having reached 68° the flask is removed and placed at
+once in another water-bath at the temperature of the room, to which
+temperature the contents of the flask are cooled as rapidly as
+possible. To make the polarimetric observation a tube twenty-two
+centimeters in length is filled with the inverted sugar solution by
+means of a tubulure in its center, which serves not only the purpose of
+filling the tube but also afterwards to carry the thermometer, by means
+of which the temperature of observation can be taken. If the sugar
+solution be turbid, or contain any lead chlorid due to the previous use
+of basic lead acetate in clarification, it should be filtered before
+being introduced into the observation tube. This tube being one-tenth
+longer than the original compensates for the dilution caused by the
+addition of the hydrochloric acid in inversion.</p>
+
+<p>When reading, the bulb of the thermometer should be withdrawn far
+enough to permit the free passage of the ray of light and the exact
+temperature of the solution noted.</p>
+
+<p>The above outline of Clerget’s method of inversion is given in order
+that the analyst may compare it with any of the variations which he may
+find in other works. The chief points to which attention is called,
+are, first, the fact that only a little over sixteen grams of sugar are
+used for ten cubic centimeters of strong hydrochloric acid, and second,
+that the time of heating is exactly fifteen minutes, during which time
+the contents of the flask should be raised from room temperature to
+exactly 68°.</p>
+
+<p>From the above it is seen that the process of Clerget, as originally
+described, can be applied directly to all instruments, using
+approximately sixteen grams of sugar in 100 cubic centimeters.
+Experience has also shown that even when larger quantities of sugar
+are employed, as for instance, approximately twenty-six grams,
+the inversion is effected with practical completeness in the same
+circumstances. It is advised, therefore, that in all analytical
+processes, in which cane sugar is to be determined by the process of
+inversion with an acid, the original directions of Clerget be followed
+as strictly as possible. Experience has shown that no one of the
+variations proposed for Clerget’s original method has any practical
+advantage and the analyst is especially cautioned against those methods
+<span class="pagenum"><a id="Page_108"></a>[Pg 108]</span>
+of inversion in which the temperature is continued at 68° for fifteen
+minutes or in which it is allowed to go above that degree.</p>
+
+<p><b>93. Influence of Strength of Solution and Time of Heating on the
+Inversion of Sucrose.</b>—As has been intimated, the strength of a
+sugar solution and the time of heating with hydrochloric acid are
+factors that must be considered in determining a formula for the
+calculation of sucrose by inversion. The Clerget formula holds good
+only for the conditions specified and these conditions must be rigidly
+adhered to in order to secure the proper results. This matter has been
+thoroughly studied by Bornträger, who also gives a nearly complete
+bibliography of the subject.<a id="FNanchor_54" href="#Footnote_54" class="fnanchor">[54]</a>
+As a result of his investigations it seems well established that the
+original Clerget formula is practically correct for the conditions
+indicated, Bornträger modifying it only by substituting in the formula
+143.66 for 144. This is so nearly the same as the Clerget factor
+that it is not advisable to substitute it therefor. If, however,
+the inverted sugar solution be diluted to double its volume before
+polarization the factor proposed by Landolt, <i>viz.</i>, 142.4, gives
+more nearly accurate results. If the hydrochloric acid be neutralized
+before polarization by an alkaline body, the character of the salt
+which is formed also influences, to a greater or less extent, the
+specific rotatory power of the solution. Hydrochloric acid itself also
+influences the rotation to a certain degree.<a id="FNanchor_55" href="#Footnote_55" class="fnanchor">[55]</a></p>
+
+<p id="P_94"><b>94. Calculation of Results.</b>—The percentage of sucrose in
+a solution which has been polarized before and after inversion is
+calculated by an appropriate formula from the data obtained or is taken
+directly from tables. These tables are too long to insert here, and in
+point of fact the calculation can be made from the formula almost as
+quickly as the result can be taken from a table.</p>
+
+<p>Two factors are commonly used in the calculations, one based on
+the supposition that a sugar solution polarizing 100° to the right
+will, after inversion, give a reading of 44° to the left, at zero
+temperature. In the second formula in common use the polarization to
+the left in the circumstances mentioned above is assumed to be 42.4, a
+number reached by Landolt after a long series of experiments.<a id="FNanchor_56" href="#Footnote_56" class="fnanchor">[56]</a>
+The principle of the calculation of the percentage of sucrose is based upon
+<span class="pagenum"><a id="Page_109"></a>[Pg 109]</span>
+the original observation of Clerget to the effect that the algebraic
+difference of the two readings, divided by 144, less half of the
+temperature, will give the percentage of sucrose desired. The formula
+by which this is obtained is</p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>S</i> = &nbsp;</td>
+      <td class="tdc bb" colspan="2"><i>a</i> - <i>b</i></td>
+      <td class="tdl_wsp" rowspan="2">.</td>
+   </tr><tr>
+      <td class="tdl"><i>K</i> -</td>
+      <td class="tdl bb">&nbsp; <i>t</i> &nbsp;</td>
+   </tr><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdc">2</td>
+      <td class="tdl">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>In this formula <i>a</i> is the polarization on the sugar scale before
+inversion, <i>b</i> the polarization after inversion, <i>K</i> the
+constant representing the algebraic difference of the two polarizations
+of pure sugar at 0° and <i>t</i> the temperature of the observation.
+To <i>K</i> may be assigned the values 144 or 142.4, the one in more
+common use. In case the polarization, after inversion, is to the
+left, which is more commonly the case, the sum of the two readings
+is taken for <i>a</i> - (-<i>b</i>) = <i>a</i> + <i>b</i>; when both
+polarizations are to the right or left the difference is taken. S is
+the percentage of sucrose desired.</p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl_top" rowspan="3"><i>Example.—</i></td>
+      <td class="tdl">Let the polarization before inversion be</td>
+      <td class="tdr_wsp">&nbsp;&emsp;+95</td>
+   </tr><tr>
+      <td class="tdl_ws2">and after inversion</td>
+      <td class="tdr_wsp">-26</td>
+   </tr><tr>
+      <td class="tdl_ws2">and the temperature</td>
+      <td class="tdr">20°</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">Then <i>S</i> = &nbsp;</td>
+      <td class="tdc bb">95 + 26</td>
+      <td class="tdl_wsp" rowspan="2">= 121 ÷ 134 = 90.6.</td>
+   </tr><tr>
+      <td class="tdc">144 - 10</td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="fs_110">Substituting the value 142.4 for <i>K</i>, the result of the
+calculation is 91.4.</p>
+
+<p>In high grade sugars, therefore, the difference in the results secured
+by taking the two values of <i>K</i> amounts to about 1 per cent of
+sucrose.</p>
+
+<p>For a further discussion of the theory and practice of inversion the
+reader is referred to the articles of Herles, Herzfeld, and Wohl.<a id="FNanchor_57" href="#Footnote_57" class="fnanchor">[57]</a></p>
+
+<p id="P_95"><b>95. Method Of Lindet.</b>—Courtonne recommends the method of Lindet
+for securing the inversion instead of the method of Clerget.<a id="FNanchor_58" href="#Footnote_58" class="fnanchor">[58]</a>
+Modified by Courtonne, the method is as follows:</p>
+
+<p>Make two or three times the normal weight of sugar dissolved in water
+to a volume of 200 or 300 cubic centimeters, as the case may be. After
+thoroughly mixing proceed as follows:</p>
+
+<p><i>First, to Obtain the Polarization Direct.</i>—Place fifty or 100
+cubic centimeters of the prepared solution in a flask marked at fifty
+and fifty-five or at 100 and 110 cubic centimeters, add a sufficient
+quantity of lead acetate to secure a complete clarification, make the
+<span class="pagenum"><a id="Page_110"></a>[Pg 110]</span>
+volume to fifty-five or 110 cubic centimeters, shake thoroughly,
+filter, and polarize in a 220 millimeter tube.</p>
+
+<p><i>Second, to Obtain the Rotation after Inversion.</i>—Place twenty
+cubic centimeters of the original solution, in a flask marked at
+fifty cubic centimeters, containing five grams of powdered zinc. The
+flask should be placed in boiling water. Add, little by little so as
+to avoid a too rapid evolution of hydrogen, ten cubic centimeters of
+hydrochloric acid made of equal parts of the strongest acid and water.
+After the operation is terminated, cool to the temperature of the room,
+make the volume to fifty cubic centimeters, polarize, and determine
+the rotation. The volume occupied by the zinc which is not dissolved,
+will be about one-half cubic centimeter, hence the deviation should be
+multiplied by the factor 2.475 in order to get the true deviation which
+would have been produced by the pure liquor. We have then:</p>
+
+<ul class="index">
+<li class="isub2"><i>A</i> = the deviation direct.</li>
+<li class="isub2"><i>B</i> = the deviation after inversion.</li>
+<li class="isub2"><i>C</i> = the algebraic difference of the deviations.</li>
+</ul>
+
+<p>The amount of sucrose, therefore, would be calculated by the formula of
+Creydt,<a id="FNanchor_59" href="#Footnote_59" class="fnanchor">[59]</a></p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>X</i> = &nbsp;</td>
+      <td class="tdc bb"><i>C</i> - 0.493<i>A</i></td>
+      <td class="tdl_wsp" rowspan="2"> ;</td>
+   </tr><tr>
+      <td class="tdc">0.827</td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="no-indent">for raffinose the formula would be</p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>Y</i> = &nbsp;</td>
+      <td class="tdc bb"><i>A</i> - <i>S</i></td>
+      <td class="tdl_wsp" rowspan="2"> ;</td>
+   </tr><tr>
+      <td class="tdc">1.57</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>in which <i>S</i> is the deviation due to the sucrose present. The
+solutions inverted in the manner described are absolutely colorless.
+There is no need of employing bone-black to secure the saccharimetric
+reading nor does it present any uncertainty. It is thought by Courtonne
+that this method will soon take the place of the method of Clerget on
+account of the advantages above mentioned. The method will be somewhat
+improved by adopting the following suggestions:</p>
+
+<p>1. Instead of allowing any arbitrary number for the volume of the
+undissolved zinc, decant the liquid, after inversion, into another
+flask and wash repeatedly with hot water until all trace of sugar is
+removed from the flask in which the inversion took place.</p>
+
+<p>2. Instead of polarizing in a 200 millimeter tube make the observation
+in a 500 millimeter tube, which will permit of the reading being made
+without any correction whatever.
+<span class="pagenum"><a id="Page_111"></a>[Pg 111]</span></p>
+
+<p><b>96. Inversion by Means of Invertase.</b>—Instead of using acids
+for the inversion of cane sugar the hydrolysis can be easily effected
+by means of a ferment derived from yeast. A complete history of the
+literature and characteristics of this ferment, together with a study
+of its properties and the various methods of preparing it, has been
+given by O’Sullivan and Tompson.<a id="FNanchor_60" href="#Footnote_60" class="fnanchor">[60]</a>
+In the preparation of invertase, the method found most effective is the
+following:</p>
+
+<p>The yeast is allowed to liquify for at least a month in a fairly warm
+room without stirring. At the end of this time the surface is removed
+and any supernatant liquid poured away. The lower sedimentary part is
+thrown on a quick-acting filter and allowed to drain for two days.
+To the filtrate, alcohol of specific gravity 0.87 is gradually added
+to the extent of one and a half times its volume, with continued and
+vigorous stirring. The process of adding the alcohol and stirring
+should require about half an hour, after which the mixture is allowed
+to stand for twenty-four hours to allow the precipitated invertase
+to settle. The supernatant liquid is poured away and the precipitate
+washed several times on successive days by decantation with alcohol of
+0.92 specific gravity. When the washings become nearly colorless the
+precipitate is thrown on a filter, allowed to drain, and immediately
+removed and mixed with a large bulk of alcohol of 0.92 specific
+gravity. The precipitate is again collected, mixed thoroughly with its
+own bulk of water, and some alcohol of 0.97 specific gravity, allowed
+to stand for a few hours and thrown on a filter. The filtrate contains
+the invertase.</p>
+
+<p><b>97. Determination of Activity of Invertase.</b>—The activity of a
+solution of invertase, prepared as above, is measured by the number
+of minutes required for it to reduce to zero the optical power of a
+solution of 100 times its weight of cane sugar at a temperature of
+15°.5. In order to facilitate the action of the invertase, a trace of
+sulfuric acid is added to the solution. The manipulation is as follows:</p>
+
+<p>Fifty grams of sucrose are dissolved in water and made to a volume of
+nearly a quarter of a liter and placed in a bath maintained at 15°.5.
+Half a gram of the invertase is added, the time noted, the solution
+immediately made up to a quarter of a liter and well shaken. The
+<span class="pagenum"><a id="Page_112"></a>[Pg 112]</span>
+contents of the flask are poured rapidly into five beakers; the actual
+quantity in each beaker is not necessarily the same. To each of these
+beakers, in succession, are added the following amounts of decinormal
+sulfuric acid, <i>viz.</i>, one-tenth, three-tenths, six-tenths, one,
+and one and four-tenths cubic centimeters. After an hour a small
+quantity of the solution is taken from beaker No. 3 and the reaction
+of the invertase stopped by adding a few drops of strong potassium
+hydroxid and the time of adding this reagent noted. This solution is
+then read in the polariscope and the percentage of sugar inverted is
+calculated from the formula <b>C₁₂H₂₂O₁₁ + H₂O = C₆H₁₂O₆ + C₆H₁₂O₆.</b></p>
+
+<p>The calculation of the amount of cane sugar inverted is based on the
+formula,</p>
+
+<p class="f110">(38.4 - <i>d</i>) ÷ 0.518 = <i>p</i>.</p>
+
+<p class="no-indent">In this formula <i>d</i> equals the divisions
+of the sugar scale read on the polariscope; <i>p</i> the percentage
+of cane sugar inverted; 38.4 the reading on the sugar scale of the
+original sugar solution and 51.8 the total number of divisions of the
+cane sugar scale that the polariscope reading would fall through if all
+the sugar were inverted. The observation tubes used in the polarization
+are only 100 millimeters in length. After stopping the action of the
+invertase with potassium hydroxid the solution is allowed to stand
+for some time before polarization inasmuch as the dextrose formed
+appears to assume the state of birotation and some time is required
+for it to reach its normal rotatory power. If the invertase be used
+in the alcoholic solution a sufficient quantity should be added to be
+equivalent to 0.01 of the sucrose present. The time which the contents
+of beaker No. 3 will take to reach optical activity is calculated in a
+manner described by O’Sullivan and Tompson, but too long to be inserted
+here.<a id="FNanchor_61" href="#Footnote_61" class="fnanchor">[61]</a>
+The five beakers mentioned above are examined in succession and the
+amount of sulfuric acid best suited to the maximum inversion thus
+determined. This quantity is then used in subsequent hydrolyses with
+the given sample of invertase.</p>
+
+<p>The action of invertase on sucrose is very rapid at the first and
+becomes very much slower towards the end. At a temperature of 15°.5 it
+is advisable to let the solution stand for forty-eight hours in order
+to be sure that complete inversion has taken place. For this reason the
+<span class="pagenum"><a id="Page_113"></a>[Pg 113]</span>
+method by inversion by means of invertase is one of no great practical
+importance, but it may often be useful to the analyst when the
+employment of an acid is inadmissible.</p>
+
+<p><b>98. Inversion by Yeast.</b>—Owing to the difficulty of preparing
+invertase, O’Sullivan and Thompson<a id="FNanchor_62" href="#Footnote_62" class="fnanchor">[62]</a>
+propose to use yeast as the hydrolytic agent, as first suggested by
+Kjeldahl. It is shown that in the use of yeast it is not necessary
+to employ thymol or any other antiseptic. The method of procedure is
+as follows: The cane sugar solution of usual strength should not be
+alkaline, but, if possible, should be exactly neutral. If there be any
+ferment suspected, the temperature should be momentarily raised to 80°
+to destroy its activity. The polariscopic reading of the solution is
+then taken at 15°.5 and the amount of copper reduced by the solution
+should also be determined.</p>
+
+<p>Fifty cubic centimeters of the solution are poured into a beaker and
+raised to a temperature of 55° in a constant temperature bath. Some
+brewers yeast amounting to about one-tenth of the total amount of sugar
+to be inverted, pressed in a towel, is thrown into the hot solution and
+the whole stirred until mixture is complete. The solution is left for
+four hours in the water-bath, at the end of this time it is cooled to
+15°.5, a little freshly precipitated aluminum hydroxid added, and the
+volume made to 100 cubic centimeters. A portion of this solution is
+filtered and its polariscopic reading observed. The solution is then
+left till the next day, when another polariscopic reading is taken in
+order to prove that inversion is complete. The copper reducing power is
+also determined. The method of calculating the results is the same as
+when invertase is used. The following formulas are employed.</p>
+
+<p><i>a</i> = the number of divisions indicated by the polariscopic
+reading for a 200 millimeter tube:</p>
+
+<p><i>aʹ</i> = the same number after inversion:</p>
+
+<p><i>m</i> = the number of the divisions of the polariscopic scale which
+200 millimeters of the sugar solution containing one gram of cane sugar
+per 100, alter at 15°.5 on being inverted: In the case of the ventzke
+polarimeter scale, one gram of cane sugar in 100 cubic centimeters,
+<span class="pagenum"><a id="Page_114"></a>[Pg 114]</span>
+indicates +3.84 divisions and after inversion it gives -1.34 div. In
+experiments of this kind, therefore, <i>m</i> = 5.18.</p>
+
+<p><i>P</i> = the weight of cane sugar present in 100 cubic centimeters of
+the original solution:</p>
+
+<p>The formula employed then is</p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>P</i> = &nbsp;</td>
+      <td class="tdc bb"><i>a</i> - 2<i>a</i>ʹ</td>
+      <td class="tdl_wsp" rowspan="2"> .</td>
+   </tr><tr>
+      <td class="tdc"><i>m</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p>For the copper reduction data the following are used:</p>
+
+<p><i>G</i> = the weight of 100 cubic centimeters of the original solution:</p>
+
+<p><i>Gʹ;</i> = the same for the inverted solution: Allowance must be made
+here both for the dilution and for the 5 per cent increase of the
+inverted sugar, but the latter number is so small that it need not be
+calculated accurately.</p>
+
+<p><i>w</i> = the weight of the original solution used for the estimation:</p>
+
+<p><i>wʹ</i> = the same factor for the inverted solution:</p>
+
+<p><i>k</i> = the weight of cupric oxid reduced by <i>w</i>:</p>
+
+<p><i>kʹ</i> = the same factor for <i>wʹ</i>:</p>
+
+<p><i>p</i> = the weight of cane sugar present in 100 cubic centimeters of
+the original solution: The formula to be employed then is</p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl_top" rowspan="2"><i>p</i> = 0.4308
+                  <img src="images/cbl-2.jpg" alt="" width="10" height="36" > 2 &nbsp;</td>
+      <td class="tdc bb"><i>Gʹ kʹ</i></td>
+      <td class="tdl" rowspan="2">&nbsp; - &nbsp;</td>
+      <td class="tdc bb"><i>G k</i></td>
+      <td class="tdl_wsp" rowspan="2"><img src="images/cbr-2.jpg" alt="" width="10" height="36" > .</td>
+   </tr><tr>
+      <td class="tdc"><i>wʹ</i></td>
+      <td class="tdc"><i>w</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p>This method has been applied to the estimation of cane sugar in
+molasses, apple juices and other substances. It is recommended by the
+authors as a simple and accurate means of estimating sucrose in all
+solutions containing it. The methods of making the copper reductions
+will be given hereafter.</p>
+
+<p><b>99. Application of the Process.</b>—In practice the process of
+inversion is used chiefly in the analysis of molasses and low grade
+massecuites. In approximately pure sugars the direct polarization is
+sufficiently accurate for all practical purposes. In molasses resulting
+from the manufacture of beet sugar are often found considerable
+quantities of raffinose, and the inversion process has been adapted to
+that character of samples. In molasses, in sugar cane factories, the
+disturbing factors are chiefly invert sugars and gums. The processes
+used for molasses will be given in another paragraph. In certain
+determinations of lactose the process of inversion is also practiced,
+but in this case the lactose is converted into dextrose and galactose,
+<span class="pagenum"><a id="Page_115"></a>[Pg 115]</span>
+and the factors of calculation are altogether different. The process
+has also been adapted by McElroy and Bigelow to the determination of
+sucrose in presence of lactose, and this method will be described
+further on. In general the process of inversion is applicable to the
+determination of sucrose in all mixtures of other optically active
+bodies, which are not affected by the methods of inversion employed.</p>
+
+<p id="P_100"><b>100. Determination of Sucrose and Raffinose.</b>—Raffinose
+is a sugar which often occurs in beets, and is found chiefly in the
+molasses after the chief part of the sucrose has been removed by
+crystallization. It is also found in many seeds, notably in those of
+the cotton plant. In a pure solution of sucrose and raffinose, both
+sugars may be determined by the inversion method of Creydt.<a id="FNanchor_63" href="#Footnote_63" class="fnanchor">[63]</a>
+The inversion is effected by means of hydrochloric acid in the manner
+described by Clerget. The following formulas are calculated for a
+temperature of observation of 20°, and the readings should be made as
+near that temperature as possible.</p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">(1)<span class="ws5"><i>S</i> = &nbsp;</span></td>
+      <td class="tdc bb"><i>C</i> - 0.493<i>A</i></td>
+   </tr><tr>
+      <td class="tdc">0.827</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">(2)&emsp;<i>R</i> = &nbsp;</td>
+      <td class="tdc bb"><i>A</i> - <i>S</i></td>
+      <td class="tdl" rowspan="2">= 1.017<i>A</i> - &nbsp;</td>
+      <td class="tdc bb">6</td>
+   </tr><tr>
+      <td class="tdc">1.57</td>
+      <td class="tdc">1.298</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>In these formulas <i>S</i> and <i>R</i> are the respective per cents
+of sucrose and raffinose desired, <i>A</i> the polarization in sugar
+degrees before inversion, <i>B</i> the polarization after inversion
+read at 20°, and <i>C</i> is the algebraic difference between <i>A</i>
+and <i>B</i>. It must be understood that these formulas are applicable
+only to a solution containing no other optically active substances,
+save sucrose and raffinose.</p>
+
+<p><b>101. Specific Rotatory Power.</b>—In order to compare among
+themselves the rotations produced on a plane of polarized light by
+different optically active bodies in solution, it is convenient to
+refer them all to an assumed standard. The degree of rotation which
+the body would show in this condition, is found by calculation, since,
+in reality, the conditions assumed are never found in practice. In
+the case of sugars and other optically active bodies, the standard of
+comparison is called the specific rotatory power. This factor in any
+<span class="pagenum"><a id="Page_116"></a>[Pg 116]</span>
+given case, is the angular rotation which would be produced by any
+given substance in a pure anhydrous state if it were one decimeter in
+length and of a specific gravity equal to water. These are conditions
+which evidently do not exist in the case of sugars, since crystalline
+sugar particles have no polarizing power, and it would be impossible
+to pass a ray of light through an amorphous sugar column of the length
+specified. The specific rotatory power is therefore to be regarded as a
+purely theoretical factor, calculated from the actual data obtained by
+the examination of the solution of any given substance. If the length
+of the observation tube in decimeters be represented by <i>l</i>, the
+percentage of the polarizing body in 100 grams by <i>p</i>, and the
+specific gravity of the solution by <i>d</i>, and the observed angle of
+rotation by <i>a</i>, then the factor is calculated from the formula:</p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">[<i>a</i>]<span class="fs_70"><sub><b>Dj</b></sub></span> =&nbsp;</td>
+      <td class="tdc bb"><i>a</i>. 100</td>
+      <td class="tdl" rowspan="2">&nbsp;.</td>
+   </tr><tr>
+      <td class="tdc"><i>p</i>. <i>d</i>. <i>l</i>.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The symbols Dj refer to the character of light employed, D indicating
+the monochromatic sodium flame, and j the transition tint from white light.</p>
+
+<p>If the weight of the polarizing body <i>c</i> be given or known for 100
+cubic centimeters of the solution the formula becomes</p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">[<i>a</i>]<span class="fs_70"><sub><b>Dj</b></sub></span> =&nbsp;</td>
+      <td class="tdc bb"><i>a</i>. 100</td>
+      <td class="tdl" rowspan="2">&nbsp;.</td>
+   </tr><tr>
+      <td class="tdc"><i>c</i>. <i>l</i>.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The latter formula is the one easier of application since it is only
+necessary in applying it to dissolve a given weight of the active body
+in an appropriate solvent and to complete the volume of the solution
+exactly to 100 cubic centimeters. It is therefore unnecessary in this
+case to determine the specific gravity.</p>
+
+<p><b>102. Formulas for Calculating Specific Rotatory Power.</b>—In order
+to determine the specific rotatory power (gyrodynat<a id="FNanchor_64" href="#Footnote_64" class="fnanchor">[64]</a>)
+of a given substance it is necessary to know the specific gravity and percentage
+composition or concentration of its solution, and to examine it with
+monochromatic polarized light in an instrument by which the angular
+rotation can be measured. The gyrodynat of any body changes with its
+degree of concentration, in some cases with the temperature, and always
+with the color of the light. With the red rays the gyrodynat is least
+<span class="pagenum"><a id="Page_117"></a>[Pg 117]</span>
+and itprogressively increases as the violet end of the spectrum is
+approached. In practice the yellow ray of the spectrum has been found
+most convenient for use, and in the case of sugars the gyrodynat is
+always expressed either in terms of this ray or if made with color
+compensating instruments in terms of the sensitive or transition tint.
+In the one case the symbol used is (<i>a</i>)<sub>D</sub> and in the other
+(<i>a</i>)<sub>j</sub>. From this statement it follows that (<i>a</i>)<span class="fs_70"><span class="fs_80"><sub><b>D</b></sub></span></span>
+is always numerically less than (<i>a</i>)<sub>j</sub>. Unless otherwise specified
+the gyrodynat of a body is to be considered as determined by yellow
+monochromatic light, and therefore corresponds to
+ <i>a</i><span class="fs_80"><sub><b>D</b></sub></span>.<a id="FNanchor_65" href="#Footnote_65" class="fnanchor">[65]</a></p>
+
+<p><b>103. Variations in Specific Rotatory Power.</b>—The gyrodynat of
+any optically active body varies with the nature of the solvent, the
+strength of the solution, and the temperature.<a id="FNanchor_66" href="#Footnote_66" class="fnanchor">[66]</a></p>
+
+<p>Since water is the only solvent of importance in determining the
+gyrodynat of sugars it will not be necessary here to discuss the
+influence of the nature of the solvent. In respect of the strength of
+the solution it has been established that in the case of cane sugar the
+gyrodynat decreases while with dextrose it increases with the degree
+of concentration. The influence of temperature on the gyrodynat of
+common sugars is not of great importance save in the case of levulose,
+where it is the most important factor, the gyrodynat rapidly increasing
+as the temperature falls. It is of course understood that the above
+remarks do not apply to the increase or decrease in the volume of a
+solution at changed temperatures. This influence of temperature is
+universally proportional to the change of volume in all cases, and
+this volumetric change is completely eliminated when the polarizations
+are made at the temperatures at which the solutions are completed to
+standard volumes.</p>
+
+<p><b>104. Gyrodynatic Data for Common Sugars.</b>—In the case of cane
+sugar the gyrodynat for twenty-five grams of sugar in 100 grams of
+solution at 20° is [<i>a</i>]<span class="fs_80"><sub><b>D</b></sub></span> = 66°.37.
+This is about the degree of concentration of the solutions employed in the shadow
+lamplight polariscopes. For seventeen grams of sugar in 100 grams of solution the
+number is [<i>a</i>]<span class="fs_80"><sub><b>D</b></sub></span> = 66°.49.
+This is approximately the degree of concentration for the laurent instrument.
+<span class="pagenum"><a id="Page_118"></a>[Pg 118]</span></p>
+
+<p>For any degree of concentration according to Tollens the gyrodynat
+may be computed by the following formula: [<i>a</i>]<span class="fs_80"><sub><b>D</b></sub></span>
+= 66°.386 + 0.015035<i>p</i> - 0.0003986<i>p</i>², in which <i>p</i> is the number
+of grams of sugar in 100 grams of the solution.<a id="FNanchor_67" href="#Footnote_67" class="fnanchor">[67]</a>
+In the table constructed by Schmitt the data obtained are as follows:</p>
+
+<table class="spb1 spa1">
+   <thead><tr>
+      <th class="tdc bb bt" colspan="2">In 100 parts by weight&nbsp;<br> of solution.</th>
+      <th class="tdc bl bt">Specific<br> gravity</th>
+      <th class="tdc_bott bl bt">&nbsp;Concentration&nbsp;</th>
+      <th class="tdc bl bt">Rotation <i>a</i><br>&nbsp;for 100 mm.&nbsp;</th>
+      <th class="tdc_bott bl bt">[<i>a</i>]<span class="fs_80"><sub><b>D</b></sub></span>.</th>
+   </tr><tr>
+      <th class="tdc bb">Sugar <i>p</i>.</th>
+      <th class="tdc bb bl">Water <i>q</i>.</th>
+      <th class="tdc bb bl">&nbsp;at 20° C.<i>d</i>.&nbsp;</th>
+      <th class="tdc bb bl"><i>c</i> = <i>pd</i>.</th>
+      <th class="tdc bb bl">at 20° C.</th>
+      <th class="tdc bb bl">&nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">64.9775</td>
+      <td class="tdc bl">35.0225</td>
+      <td class="tdc bl">1.31650</td>
+      <td class="tdc bl">85.5432</td>
+      <td class="tdc bl">56°.134</td>
+      <td class="tdc bl">&nbsp;65°.620&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">54.9643</td>
+      <td class="tdc bl">45.0357</td>
+      <td class="tdc bl">1.25732</td>
+      <td class="tdc bl">69.1076</td>
+      <td class="tdc bl">45°.533</td>
+      <td class="tdc bl">65°.919</td>
+   </tr><tr>
+      <td class="tdc">39.9777</td>
+      <td class="tdc bl">60.0223</td>
+      <td class="tdc bl">1.17664</td>
+      <td class="tdc bl">47.0392</td>
+      <td class="tdc bl">31°.174</td>
+      <td class="tdc bl">66°.272</td>
+   </tr><tr>
+      <td class="tdc">25.0019</td>
+      <td class="tdc bl">74.9981</td>
+      <td class="tdc bl">1.10367</td>
+      <td class="tdc bl">27.5938</td>
+      <td class="tdc bl">18°.335</td>
+      <td class="tdc bl">66°.441</td>
+   </tr><tr>
+      <td class="tdc">16.9926</td>
+      <td class="tdc bl">83.0074</td>
+      <td class="tdc bl">1.06777</td>
+      <td class="tdc bl">18.1442</td>
+      <td class="tdc bl">12°.064</td>
+      <td class="tdc bl">66°.488</td>
+   </tr><tr>
+      <td class="tdc">&#8199;9.9997</td>
+      <td class="tdc bl">90.0003</td>
+      <td class="tdc bl">1.03820</td>
+      <td class="tdc bl">10.3817</td>
+      <td class="tdc bl">&#8199;6°.912</td>
+      <td class="tdc bl">66°.574</td>
+   </tr><tr>
+      <td class="tdc">&#8199;4.9975</td>
+      <td class="tdc bl">95.0025</td>
+      <td class="tdc bl">1.01787</td>
+      <td class="tdc bl">&#8199;5.0868</td>
+      <td class="tdc bl">&#8199;3°.388</td>
+      <td class="tdc bl">66°.609</td>
+   </tr><tr>
+      <td class="tdc bb">&#8199;1.9986</td>
+      <td class="tdc bl bb">98.0014</td>
+      <td class="tdc bl bb">1.00607</td>
+      <td class="tdc bl bb">&#8199;2.0107</td>
+      <td class="tdc bl bb">&#8199;1°.343</td>
+      <td class="tdc bl bb">66°.802</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>105. Bi-Rotation.</b>—Some sugars in fresh solution show a
+gyrodynat much higher than the normal, sometimes lower. The former
+phenomenon is called bi- the latter semi-rotation. Dextrose shows
+birotation in a marked degree, also maltose and lactose. After
+standing for a few hours, or immediately on boiling, solutions of these
+sugars assume their normal state of rotation. The addition of a small
+quantity of ammonia also causes the birotation to disappear.<a id="FNanchor_68" href="#Footnote_68" class="fnanchor">[68]</a>
+This phenomenon is doubtless due to a certain molecular taxis, which remains
+after solution is apparently complete. The groups of molecules thus
+held in place have a certain rotatory power of their own and this is
+superadded to that of the normal solution. After a time, under the
+stress of the action of the solvent, these groups are broken up and the
+solution then assumes its normal condition.</p>
+
+<p><b>106. Gyrodynat of Dextrose.</b>—The gyrodynat of dextrose, as has
+already been mentioned, increases with the degree of concentration,
+thus showing a property directly opposite that of sucrose.</p>
+
+<p>The general formula for the anhydrous sugar is [<i>a</i>]<span class="fs_80"><sub><b>D</b></sub></span> = 52.°718
++ 0.017087<i>p</i> + 0.0004271<i>p</i>². In this formula <i>p</i>
+represents the grams of dextrose in 100 grams of the solution. In a ten
+per cent solution the gyrodynat of dextrose is therefore nearly exactly
+[<i>a</i>]<span class="fs_80"><sub><b>D</b></sub></span>20° = 53°.
+As calculated by Tollens the gyrodynats corresponding to several
+degrees of concentration are shown in the following table:
+<span class="pagenum"><a id="Page_119"></a>[Pg 119]</span></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb"><i>p</i> = grams in 100<br>&nbsp;grams of solution.&nbsp;</th>
+      <th class="tdc">&nbsp;</th>
+      <th class="tdc bb">&nbsp;[<i>a</i>]<span class="fs_80"><sub><b>D</b></sub></span>20°
+                          calculated for&nbsp;<br> anhydrous dextrose.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">&#8199;7.6819</td>
+      <td class="tdc" rowspan="12">&nbsp;&emsp;&nbsp;</td>
+      <td class="tdc">52°.89</td>
+   </tr><tr>
+      <td class="tdc">&#8199;9.2994</td>
+      <td class="tdc">52°.94</td>
+   </tr><tr>
+      <td class="tdc">&#8199;9.3712</td>
+      <td class="tdc">52°.94</td>
+   </tr><tr>
+      <td class="tdc">10.0614</td>
+      <td class="tdc">52°.96</td>
+   </tr><tr>
+      <td class="tdc">10.6279</td>
+      <td class="tdc">52°.98</td>
+   </tr><tr>
+      <td class="tdc">12.9508</td>
+      <td class="tdc">53°.05</td>
+   </tr><tr>
+      <td class="tdc">18.6211</td>
+      <td class="tdc">53°.25</td>
+   </tr><tr>
+      <td class="tdc">31.6139</td>
+      <td class="tdc">53°.83</td>
+   </tr><tr>
+      <td class="tdc">40.7432</td>
+      <td class="tdc">54°.34</td>
+   </tr><tr>
+      <td class="tdc">43.9883</td>
+      <td class="tdc">54°.54</td>
+   </tr><tr>
+      <td class="tdc">53.0231</td>
+      <td class="tdc">55°.17</td>
+   </tr><tr>
+      <td class="tdc">82.6111</td>
+      <td class="tdc">57°.80</td>
+   </tr>
+ </tbody>
+</table>
+
+<p id="P_107"><b>107. Gyrodynats of Other Sugars.</b>—Of the other sugars it will be
+sufficient to mention only levulose, maltose, lactose, and raffinose.
+For complete tables of gyrodynatic powers the standard books on
+carbohydrates may be consulted.<a id="FNanchor_69" href="#Footnote_69" class="fnanchor">[69]</a></p>
+
+<p>The gyrodynat of levulose is not definitely established. At 14° the
+number is nearly expressed by [<i>a</i>]<span class="fs_80"><sub><b>D</b></sub></span>14° = -93°.7.</p>
+
+<p>Invert sugar, which should consist of exactly equal molecules of
+dextrose and levulose, has a gyrodynat expressed by the formula
+[<i>a</i>]<span class="fs_80"><sub><b>D</b></sub></span>0° = -27°.9,
+with a concentration equivalent to 17.21 grams of sugar in 100 cubic
+centimeters. The gyrodynat decreases with increase of temperature,
+according to the formula [<i>a</i>]<span class="fs_80"><sub><b>D</b></sub></span><i>t</i>°
+= -&nbsp;(27°.9 - 0.32<i>t</i>°). According to this formula the solution is
+neutral to polarized light at 87°.2, and this corresponds closely to
+the data of experiment.</p>
+
+<p>Maltose, in a ten per cent solution at 20°, shows a gyrodynat of
+[<i>a</i>]<span class="fs_80"><sub><b>D</b></sub></span>20° = 138°.3.</p>
+
+<p>The general formula for other degrees of concentration is
+[<i>a</i>]<span class="fs_80"><sub><b>D</b></sub></span> = 140°.375 - 0.01837<i>p</i> - 0.095<i>t</i>,
+in which <i>p</i> represents the number of grams in 100 grams of the solution
+and <i>t</i> the temperature of observation.</p>
+
+<p>In the case of lactose [<i>a</i>]<span class="fs_80"><sub><b>D</b></sub></span> = 52°.53,
+and this number does not appear to be greatly influenced by the degree of concentration; but
+is somewhat diminished by a rising temperature.</p>
+
+<p>The gyrodynat of raffinose in a ten per cent solution is
+[<i>a</i>]<span class="fs_80"><sub><b>D</b></sub></span> = 104°.5.
+<span class="pagenum"><a id="Page_120"></a>[Pg 120]</span></p>
+
+<h3>CHEMICAL METHODS OF<br> ESTIMATING SUGARS.</h3>
+
+<p><b>108. General Principles.</b>—The methods for the chemical
+estimation of sugars in common use depend on the reducing actions
+exerted on certain metallic salts, whereby the metal itself or some
+oxid thereof, is obtained. The reaction is either volumetric or
+the resulting oxid or metal may be weighed. The common method is,
+therefore, resolved into two distinct processes, and each of these
+is carried out in several ways. Not all sugars have the faculty of
+exerting a reducing action on highly oxidized metallic salts and the
+most common of them all, <i>viz.</i>, sucrose is practically without
+action. This sugar, however, by simple hydrolysis, becomes reducing,
+but the two components into which it is resolved by hydrolytic action
+do not reduce metallic salts in the same proportion. Moreover, in all
+cases the reducing power of a sugar solution is largely dependent on
+its degree of concentration, and this factor must always be taken into
+consideration. Salts of copper and mercury are most usually selected to
+measure the reducing power of a sugar and in point of fact copper salts
+are almost universally used. Copper sulfate and carbonate are the salts
+usually employed, and of these the sulfate far more frequently, but
+after conversion into tartrate. Practically, therefore, the study of
+the reducing action of sugar as an analytical method will be confined
+almost exclusively to the determination of its action on copper
+tartrate.</p>
+
+<p>Direct gravimetric methods are also practiced to a limited extent in
+the determination of sugars as in the use of the formation of sucrates
+of the alkaline earths and of the combinations which certain sugars
+form with phenylhydrazin. Within a few years this last named reaction
+has assumed a marked degree of importance as an analytical method.
+The most practical treatment of this section, therefore, for the
+limited space which can be given it, will be the study of the reducing
+action of sugars, both from a volumetric and gravimetric point of
+view, followed by a description of the best approved methods of the
+direct precipitation of sugars by such reagents as barium hydroxid and
+phenylhydrazin.
+<span class="pagenum"><a id="Page_121"></a>[Pg 121]</span></p>
+
+<h3>VOLUMETRIC METHODS.</h3>
+
+<p><b>109. Classification.</b>—Among the volumetric methods will be given
+those which are in common use or such as have been approved by the
+practice of analysts. Since the use of mercuric salts is now practiced
+to a limited extent, only a brief study of that process will be
+attempted. With the copper methods a somewhat extended description will
+be given of those depending on the use of copper sulfate, and a briefer
+account of the copper carbonate process.</p>
+
+<p>In the copper sulfate method two distinct divisions must be noted,
+<i>viz.</i>, first an indirect process depending first upon the
+reduction of the copper to a suboxid, the subsequent action of this
+body on iron salts, measured finally by titration with potassium
+permanganate; and second, a direct process determined either by the
+disappearance of the blue color from the copper solution, or by the
+absence of copper from a drop of the solution withdrawn and tested
+with potassium ferrocyanid. This last mentioned reaction is one which
+is found in common use. The volumetric methods are not, as a rule,
+as accurate as the gravimetric, depending on weighing the resultant
+metal, but they are far more rapid and well suited to technical control
+determinations.</p>
+
+<p><b>110. Reduction of Mercuric Salts.</b>—The method of determining
+sugar by its action on mercuric salts, is due to Knapp.<a id="FNanchor_70" href="#Footnote_70" class="fnanchor">[70]</a>
+The method is based on the observation that dextrose and other allied
+sugars, will reduce an alkaline solution of mercuric cyanid, and that
+the mercury will appear in a metallic state.</p>
+
+<p>The mercuric liquor is prepared by adding to a solution of ten grams of
+mercuric cyanid, 100 cubic centimeters of a solution of caustic soda of
+1.145 specific gravity, and making the volume to one liter with water.
+The solution of sugar to be titrated, should be as nearly as possible
+of one per cent strength.</p>
+
+<p>To 100 cubic centimeters of the boiling solution, the sugar solution is
+added in small portions from a burette and in such a way as to keep the
+whole mass in gentle ebullition.</p>
+
+<p>To determine when all the mercuric salt has been decomposed, a drop of
+the clear boiling liquid is removed and brought into contact with a
+drop of stannous chlorid solution on a white surface. A brownish black
+<span class="pagenum"><a id="Page_122"></a>[Pg 122]</span>
+coloration or precipitate will indicate that the mercury is not all
+precipitated. Fresh portions of the sugar must then be added, until no
+further indication of the presence of mercury is noted. The approximate
+quantity of sugar solution required to precipitate the mercury having
+thus been determined, the process is repeated by adding rapidly, nearly
+the quantity of sugar solution required, and then only a few drops at a
+time, until the reduction is complete.</p>
+
+<p>One hundred cubic centimeters of the mercuric cyanid solution prepared
+as directed above, will be completely reduced by</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">202</td>
+      <td class="tdl_wsp">milligrams</td>
+      <td class="tdl_wsp">of</td>
+      <td class="tdl_wsp">dextrose,</td>
+   </tr><tr>
+      <td class="tdl">200</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">invert sugar,</td>
+   </tr><tr>
+      <td class="tdl">198</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">levulose,</td>
+   </tr><tr>
+      <td class="tdl">308</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">maltose,</td>
+   </tr><tr>
+      <td class="tdl">311</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">lactose.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>By reason of the unpleasant odor of the boiling mercuric cyanid when
+in presence of a reducing agent, the process should be conducted in a
+well ventilated fume chamber. With a little practice the process is
+capable of rapid execution, and gives reasonably accurate results.</p>
+
+<p><b>111. Sachsse’s Solution.</b>—The solution of mercuric salts
+proposed by Sachsse, is made by dissolving eighteen grams of mercuric
+iodid in twenty-five cubic centimeters of an aqueous solution of
+potassium iodid. To this solution are added 200 cubic centimeters of
+potash lye, containing eighty grams of caustic potash. After mixing the
+solution, the volume is completed to one liter. The sugar solutions
+used to reduce this mixture, should be more dilute than those employed
+with the mercuric cyanid, and should not be over one-half per cent in
+strength. The end of the reduction is determined as already described.
+After a preliminary trial, nearly all the sugar necessary to complete
+reduction, should be added at once, and the end of the reduction then
+determined by the addition of successive small quantities. One hundred
+cubic centimeters of the mercuric iodid solution prepared as directed
+above, require the following quantities of sugar to effect a complete
+reduction:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">325</td>
+      <td class="tdl_wsp">milligrams</td>
+      <td class="tdl_wsp">of</td>
+      <td class="tdl_wsp">dextrose,</td>
+   </tr><tr>
+      <td class="tdl">269</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">invert sugar,</td>
+   </tr><tr>
+      <td class="tdl">213</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">levulose,</td>
+   </tr><tr>
+      <td class="tdl">491</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">maltose,</td>
+   </tr><tr>
+      <td class="tdl">387</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">lactose.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_123"></a>[Pg 123]</span>
+By reason of the great difference between the reducing power of
+dextrose and levulose in this solution, it has been used in combination
+with the copper reduction method, to be described, to determine the
+relative proportion of dextrose and levulose in a
+mixture.<a id="FNanchor_71" href="#Footnote_71" class="fnanchor">[71]</a></p>
+
+<p>It is now known that copper solutions require slightly different
+quantities of dextrose, levulose, or invert sugar to effect complete
+reduction, but the variations are not great and in the calculation
+above mentioned, it may be assumed that these differences do not exist.</p>
+
+<p>Instead of using stannous chlorid as an indicator, the end of the
+reaction may be determined as follows: A disk of filtering paper is
+placed over a small beaker containing some ammonium sulfid. A drop of
+the clear hot solution is placed on this disk, and if salts of mercury
+be still present a dark stain will be produced; or a drop of the
+ammonium sulfid may be brought near the moist spot formed by the drop
+of mercury salt. An alkaline solution of zinc oxid may also be used.</p>
+
+<p>The methods depending on the use of mercuric salts have, of late, been
+supplanted by better processes, and space will not be given here to
+their further discussion.</p>
+
+<p><b>112. The Volumetric Copper Methods.</b>—The general principle on
+which these methods depend, is found in the fact that certain sugars,
+notably, dextrose, (glucose), levulose, (fructose), maltose and
+lactose, have the property of reducing an alkaline solution of copper
+to a lower state of combination, in which the copper is separated as
+cuprous oxid. The end of the reaction is either determined by the
+disappearance of the blue color of the solution, or by the reaction
+produced by a drop of the hot filtered solution, when placed in contact
+with a drop of potassium ferrocyanid acidified with acetic.</p>
+
+<p>The copper salt which is found to give the most delicate and reliable
+reaction, is the tartrate. The number of volumetric processes proposed
+and which are in use, is very great, and an attempt even to enumerate
+all of these can not be made in this volume. A few of the most reliable
+and best attested methods will be given, representing if possible, the
+best practice in this and other countries. The rate of reduction of the
+<span class="pagenum"><a id="Page_124"></a>[Pg 124]</span>
+copper salt to suboxid, is influenced by the rate of mixing with
+the sugar solutions, the temperature, the composition of the copper
+solution and the strength of the sugar solution.</p>
+
+<p>The degree of reduction is also modified by the rate at which the
+sugar solution is added, and by the degree and duration of heating,
+and all these variables together, make the volumetric methods somewhat
+difficult and their data, to a certain extent, discordant. By reason,
+however, of the ease with which they are applied and the speed of their
+execution, they are invaluable for approximately correct work and for
+use in technical control.</p>
+
+<p id="P_113"><b>113. Historical.</b>—It is not the purpose in this paragraph
+to trace the development of the copper reduction method for the
+determination of reducing sugars, but only to refer to the beginning of
+the exact analytical application of it.</p>
+
+<p>Peligot, as early as 1844, made a report to the Society for the
+Encouragement of National Industry on methods proposed by Barreswil
+and Fromherz for the quantitive estimation of sugar by means of copper
+solution.<a id="FNanchor_72" href="#Footnote_72" class="fnanchor">[72]</a>
+These methods were based on the property of certain sugars to reduce alkaline
+copper solution to a state of cuprous oxid first announced by
+Trommer.<a id="FNanchor_73" href="#Footnote_73" class="fnanchor">[73]</a>
+This was followed by a paper by Falck on the quantitive determination of
+sugar in urine.<a id="FNanchor_74" href="#Footnote_74" class="fnanchor">[74]</a></p>
+
+<p>In 1848 the methods, which have been proposed, were critically examined
+by Fehling, and from the date of his paper the determination of sugar
+by the copper method may be regarded as resting on a scientific
+basis.<a id="FNanchor_75" href="#Footnote_75" class="fnanchor">[75]</a></p>
+
+<p>Since the date mentioned the principal improvements in the process
+have been in changing the composition of the copper solution in order
+to render it more stable, which has been accomplished by varying the
+proportions of copper sulfate, alkali and tartaric acid. For the better
+keeping of the solution the method of preserving the copper sulfate and
+the alkaline tartrates in separate flasks and only mixing them at the
+time of use has been found very efficacious.<a id="FNanchor_76" href="#Footnote_76" class="fnanchor">[76]</a>
+For testing for the end of the reaction by means of an acetic acid
+solution of potassium ferrocyanid the filtering tube suggested by the
+author, the use of which will be described further on, has proved quite
+<span class="pagenum"><a id="Page_125"></a>[Pg 125]</span>
+useful. Pavy has suggested that by the addition of ammonia to the copper
+solution the precipitated suboxid may be kept in solution and the end of
+the reaction thus easily distinguished by the disappearance of the blue
+color.<a id="FNanchor_77" href="#Footnote_77" class="fnanchor">[77]</a>
+Allen has improved on this method by covering the hot mixture with a layer
+of paraffin oil whereby any oxidation of the suboxid is prevented.<a id="FNanchor_78" href="#Footnote_78" class="fnanchor">[78]</a></p>
+
+<p>The introduction and development of the gravimetric process depending
+on securing the reduced copper oxid in a metallic state as developed by
+Allihn, Soxhlet, and others, completes the resumé of this brief sketch
+of the rise and development of the process.</p>
+
+<p><b>114. Action of Alkaline Copper Solution on Dextrose.</b>—The
+action to which dextrose and other reducing sugars are subjected in
+the presence of a hot alkaline copper solution is two-fold in its
+nature. In the first place there is an oxidation of the sugar which is
+transformed into tartronic, formic and oxalic acids, the two latter in
+very small quantities. At the same time another part of the sugar is
+attacked directly by the alkali and changed to complex products among
+which have been detected lactic, oxyphenic and oxalic acids, also two
+bodies isomeric with dioxyphenolpropionic acid. When the sugar is in
+large excess melassic and glucic acids have also been detected. The
+glucic acid may be regarded as being formed by simple dehydration but
+becomes at once resolved into pyrocatechin and gluconic acid according
+to the reaction <b>C₁₂H₁₈O₉ = C₆H₆O₂ + C₅H₁₂O₇</b>. The gluconic acid also is
+decomposed and gives birth to lactic and glyceric acids according to
+the formula <b>C₆H₁₂O₇ = C₃H₆O₃ + C₃H₆O₄</b>. The glyceric acid also in the
+presence of a base is changed into lactic and oxalic acids. Between
+lactic acid and pyrocatechin, existing in a free state, there is
+produced a double reciprocal etherification in virtue of which there
+arise two ethers isomeric with hydrocaffeic acid, <b>C₉H₁₀O₄</b>. One of these
+bodies is an acid and corresponds to the constitution</p>
+
+<ul class="index fs_110">
+<li class="isub6">CH₃</li>
+<li class="isub5">&nbsp;&emsp;/</li>
+<li class="isub5">&nbsp; O ── CH</li>
+<li class="isub5">/&emsp; \</li>
+<li class="isub3">C₆H₄ <span class="ws2">CO₂H&emsp;(2)</span></li>
+<li class="isub5">\</li>
+<li class="isub5">OH&emsp;(2)</li>
+</ul>
+
+<p class="no-indent">and the other is of an alcoholic nature corresponding to the formula
+<span class="pagenum"><a id="Page_126"></a>[Pg 126]</span></p>
+
+<ul class="index fs_110">
+<li class="isub5">&nbsp;CO₂ ── CHOH ── CH₃&emsp;(1)</li>
+<li class="isub5">/</li>
+<li class="isub3">C₆H₄</li>
+<li class="isub5">\</li>
+<li class="isub5">OH₂&emsp;(2)</li>
+</ul>
+
+<p>Of all these products only oxyphenic and lactic acids and their ethers
+and oxalic acid remain unchanged and they can be isolated. All the
+others are transformed in an acid state and they can only be detected
+by operating in the presence of metallic oxids capable of precipitating
+them at the time of their formation.<a id="FNanchor_79" href="#Footnote_79" class="fnanchor">[79]</a></p>
+
+<p><b>115. Fehling’s Solution.</b>—The copper solution which has been
+most used in the determination of reducing sugars is the one proposed
+by Fehling as a working modification of the original reagent used by
+Trommer.<a id="FNanchor_80" href="#Footnote_80" class="fnanchor">[80]</a></p>
+
+<p>Following is the formula for the preparation of the fehling solution:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Pure crystallized copper sulfate CuSO₄.5H₂O,&emsp;&nbsp;</td>
+      <td class="tdr_wsp">34.64</td>
+      <td class="tdr">grams:</td>
+   </tr><tr>
+      <td class="tdl">Potassium tartrate,</td>
+      <td class="tdr_wsp">150.00</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl">Sodium hydroxid,</td>
+      <td class="tdr_wsp">90.00</td>
+      <td class="tdc">”</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The copper sulfate is dissolved in water and the potassium tartrate in
+the aqueous solution of the sodium hydroxid which should have a volume
+of about 700 cubic centimeters. The two solutions are mixed and the
+volume completed to a liter. Each cubic centimeter of this solution
+will be reduced by five milligrams of dextrose, equivalent to four and
+a half milligrams of sucrose.</p>
+
+<p>The reaction which takes place is represented by the following
+molecular proportions:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">C₆H₁₂O₆</td>
+      <td class="tdc_top" rowspan="3">&nbsp;&emsp;=</td>
+      <td class="tdl">&nbsp;&emsp;10CuSO₄.5H₂O</td>
+   </tr><tr>
+      <td class="tdl">Dextrose.</td>
+      <td class="tdl">&nbsp;&emsp;Copper sulfate.&emsp;&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">180</td>
+      <td class="tdc">2494</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Fehling’s solution is delicate in its reactions but does not keep well,
+depositing cuprous oxid on standing especially in a warm place exposed
+to light. The fehling liquor was soon modified in its constitution by
+substituting 173 grams of the double sodium and potassium tartrate for
+the neutral potassium tartrate first used, and, in fact, the original
+fehling reagent contained forty grams of copper sulfate instead of the
+<span class="pagenum"><a id="Page_127"></a>[Pg 127]</span>
+quantity mentioned above. Other proportions of the ingredients are also
+given by many authors as fehling solution.</p>
+
+<p><b>116. Comparison of Copper Solutions for Oxidizing Sugars.</b>—For
+the convenience of analysts there is given below a tabular comparison
+of the different forms of fehling liquor which have been proposed
+for oxidizing sugars. The table is based on a similar one prepared
+by Tollens and Rodewald, amended and completed by Horton.<a id="FNanchor_81" href="#Footnote_81" class="fnanchor">[81]</a> The
+solutions are arranged alphabetically according to authors’ names:</p>
+
+<div class="blockquot">
+<p class="no-indent">1. <i>Allihn</i>:</p>
+
+<p>34.6 grams copper sulfate, solution made up to half a liter; 173
+grams potassium-sodium tartrate; 125 grams potassium hydroxid
+(equivalent to 89.2 grams sodium hydroxid) solution made up to
+half a liter.</p>
+
+<p class="no-indent">2. <i>A. H. Allen</i>:</p>
+
+<p>34.64 grams copper sulfate, solution made up to 500 cubic
+centimeters; 180 grams potassium-sodium tartrate; 70 grams sodium
+hydroxid (not less than 97° NaOH), solution made up to half a
+liter.</p>
+
+<p class="no-indent">3. <i>Bödeker</i>:</p>
+
+<p>34.65 grams copper sulfate; 173 grams potassium-sodium tartrate;
+480 cubic centimeters sodium hydroxid solution, 1.14 specific
+gravity; 67.3 grams sodium hydroxid; fill to one liter; 0.180 gram
+grape sugar reduces according to Bödeker, 36.1 cubic centimeters
+of the copper solution = 0.397 gram copper oxid. The same quantity
+of milk sugar reduces, however, only twenty-seven cubic
+centimeters copper solution = 0.298 copper oxid.</p>
+
+<p class="no-indent">4. <i>Boussingault</i>:</p>
+
+<p>40 grams copper sulfate; 160 grams potassium tartrate; 130 grams
+sodium hydroxid.</p>
+
+<p class="no-indent">5. <i>Dietzsch</i>:</p>
+
+<p>34.65 grams copper sulfate; 150 grams potassium-sodium tartrate;
+250 grams sodium hydroxid solution, 1.20 specific gravity; 150
+grams glycerol.</p>
+
+<p class="no-indent">6. <i>Fleischer</i>:</p>
+
+<p>69.278 grams copper sulfate dissolved in about half a liter of
+water, add to this 200 grams tartaric acid; fill to one liter with
+concentrated sodium hydroxid solution; twenty cubic centimeters
+copper solution = forty cubic centimeters sugar solution, that
+contain in every cubic centimeter five milligrams grape sugar.</p>
+
+<p class="no-indent">7. <i>Fehling</i>:</p>
+
+<p>40 grams copper sulfate; 160 grams di-potassium tartrate = 600-700
+cubic centimeters sodium hydroxid solution, 1.12 specific gravity,
+or from 54.6 to 63.7 grams sodium hydroxid, fill to 1154.4 cubic
+
+<span class="pagenum"><a id="Page_128"></a>[Pg 128]</span>
+
+centimeters.</p>
+
+<p class="no-indent">8. <i>Gorup-Besanez</i>:</p>
+
+<p>34.65 grams copper sulfate; 173 grams potassium-sodium tartrate;
+480 cubic centimeters sodium hydroxid solution, 1.14 specific
+gravity; equal 67.3 sodium hydroxid. Fill to one liter.</p>
+
+<p class="no-indent">9. <i>Grimaux</i>:</p>
+
+<p>40 grams copper sulfate; 160 grams potassium-sodium tartrate;
+600-700 cubic centimeters sodium hydroxid solution, 1.20 specific
+gravity, equal to 92.5-107.9 grams sodium hydroxid. Fill to
+1154.4 cubic centimeters. Ten cubic centimeters of this solution
+are completely decolorized by 0.050 gram glucose.</p>
+
+<p class="no-indent">10. <i>Holdefleis</i>:</p>
+
+<p>34.632 grams copper sulfate in one liter of water; 125 grams
+potassium hydroxid, equivalent to 89.2 grams sodium hydroxid; 173
+grams potassium-sodium tartrate. Fill to one liter.</p>
+
+<p class="no-indent">11. <i>Hoppe-Seyler</i>:</p>
+
+<p>34.65 grams copper sulfate; 173 grams potassium-sodium tartrate;
+600-700 cubic centimeters sodium hydroxid solution, 1.12 specific
+gravity; equal to 63.0-73.5 grams potassium hydroxid. Fill to
+one liter. One cubic centimeter is reduced by exactly 0.005 gram
+grape sugar.</p>
+
+<p class="no-indent">12. <i>Krocker</i>:</p>
+
+<p>6.28 grams copper sulfate; 34.6 grams potassium-sodium tartrate;
+100 cubic centimeters sodium hydroxid solution, 1.14 specific
+gravity. Fill to 200 cubic centimeters. In 100 cubic centimeters
+of this solution is contained 0.314 gram copper sulfate, which is
+reduced by 0.050 grape sugar.</p>
+
+<p class="no-indent">13. <i>Liebermann</i>:</p>
+
+<p>4 grams copper sulfate; 20 grams potassium-sodium tartrate; 70
+grams sodium hydroxid solution, 1.12 specific gravity. Fill to
+115.5 cubic centimeters.</p>
+
+<p class="no-indent">14. <i>Löwe</i>:</p>
+
+<p>15 grams copper sulfate; 60 grams glycerol; 80 cubic centimeters
+sodium hydroxid, 1.34 specific gravity; 160 cubic centimeters
+water. Fill to half a liter.</p>
+
+<p class="no-indent">15. <i>Mohr</i>:</p>
+
+<p>34.64 copper sulfate; 150 grams di-potassium tartrate; 600-700
+cubic centimeters sodium hydroxid solution, 1.12 specific
+gravity, equal to 70.5-82.3 grams sodium hydroxid. Fill to one
+liter.</p>
+
+<p class="no-indent">16. <i>Märcker</i>:</p>
+
+<p>35 grams copper sulfate, solution made up to one liter: 175
+grams potassium-sodium tartrate; 125 grams potassium hydroxid,
+equivalent to 89.2 grams sodium hydroxid, solution made up to one
+liter.</p>
+
+<p class="no-indent">17. <i>Maumenè</i>:</p>
+
+<p>375 grams copper sulfate; 188 grams potassium-sodium tartrate;
+<span class="pagenum"><a id="Page_129"></a>[Pg 129]</span></p>
+
+<p>166 grams potassium hydroxid. Fill to nine liters.</p>
+
+<p class="no-indent">18. <i>Monier</i>:</p>
+
+<p>40 grams copper sulfate; 3 grams stannic chlorid; 80 grams cream
+of tartar; 130 grams sodium hydroxid. Fill to one liter.</p>
+
+<p class="no-indent">19. <i>Neubauer and Vogel</i>:</p>
+
+<p>34.639 grams copper sulfate; 173 grams potassium-sodium tartrate;
+500-600 grams sodium hydroxid solution, 1.12 specific gravity.
+Fill to one liter.</p>
+
+<p class="no-indent">20. <i>Pasteur</i>:</p>
+
+<p>40 grams copper sulfate; 105 grams tartaric acid; 80 grams
+potassium hydroxid; 130 grams sodium hydroxid.</p>
+
+<p class="no-indent">21. <i>Possoz</i>:</p>
+
+<p>40 grams copper sulfate; 300 grams potassium-sodium tartrate;
+29 grams sodium hydroxid; 159 grams sodium bicarbonate, allow
+to stand six months before use. Fill to one liter. One cubic
+centimeter equals 0.0577 gram dextrose. One cubic centimeter
+equals 0.0548 gram cane sugar.</p>
+
+<p class="no-indent">22. <i>Rüth</i>:</p>
+
+<p>34.64 grams copper sulfate; 143 grams potassium-sodium tartrate;
+600-700 cubic centimeters sodium hydroxid solution, 1.12 specific
+gravity. Fill to one liter.</p>
+
+<p class="no-indent">23. <i>Rodewald and Tollens</i>:</p>
+
+<p>34.639 grams copper sulfate, solution made up to half a liter;
+173 grams potassium-sodium tartrate; 60 grams sodium hydroxid,
+solution made up to half a liter.</p>
+
+<p class="no-indent">24. <i>Schorlemmer</i>:</p>
+
+<p>34.64 grams copper sulfate; 200 grams potassium-sodium tartrate;
+600-700 cubic centimeters sodium hydroxid solution, 1.20 specific
+gravity. Fill to one liter.</p>
+
+<p class="no-indent">25. <i>Soxhlet</i>:</p>
+
+<p>34.639 grams copper sulfate, solution made up to half a liter.
+173 grams potassium-sodium tartrate; 51.6 grams sodium hydroxid,
+solution made up to half a liter.</p>
+
+<p class="no-indent">26. <i>Soldaini</i>:</p>
+
+<p>3.464 grams copper sulfate; 297 grams potassium bicarbonate. Fill
+to one liter.</p>
+
+<p class="no-indent">27. <i>Violette</i>:</p>
+
+<p>34.64 grams copper sulfate; 187.0 potassium-sodium tartrate; 78.0
+sodium hydroxid made up to one liter. Ten cubic centimeters equal
+0.050 gram dextrose. Ten cubic centimeters equal 0.0475 gram cane
+sugar.</p>
+</div>
+
+<p id="P_117"><b>117. Volumetric Method used in this Laboratory.</b>—The alkaline
+copper solution preferred in this laboratory has the composition
+<span class="pagenum"><a id="Page_130"></a>[Pg 130]</span>
+proposed by Violette. The copper sulfate and alkaline tartrate
+solutions are kept in separate vessels and mixed in proper proportions
+immediately before use, and diluted with about three volumes of water.
+The reduction is accomplished in a long test tube at least twenty-five
+centimeters in length, and from thirty-five to forty millimeters in diameter.</p>
+
+<p>The sugar solution employed should contain approximately one per cent
+of reducing sugar. If it should have a greater content it should be
+reduced with water to approximately the one named. If it have a less
+content, it should be evaporated in a vacuum at a low temperature
+until it reaches the strength mentioned above. A preliminary test
+will indicate almost the exact quantity of the sugar solution to be
+added to secure a complete reduction of the copper. This having been
+determined the whole quantity should be added at once to the boiling
+copper solution, the test tube held in the open flame of a lamp
+giving a large circular flame and the contents of the tube kept in
+brisk ebullition for just two minutes. The lamp is withdrawn and the
+precipitated suboxid allowed to settle. If a distinct blue color remain
+an additional quantity of the sugar solution is added and again boiled
+for two minutes. When the blue coloration is no longer distinct, the
+presence or absence of copper is determined by aspirating a drop or
+two of the hot solution with the apparatus described below. This clear
+filtered liquor is then brought into contact with a drop of potassium
+ferrocyanid solution acidulated with acetic. The production of a brown
+precipitate or color indicates that some copper is still present,
+in which case an additional quantity of the sugar solution is added
+and the operation continued as described above until after the last
+addition of sugar solution no coloration is produced.</p>
+
+<p><b>118. The Filtering Tube.</b>—The filtering tube used in the above
+operation is made of a long piece of narrow glass tubing with thick
+walls. The length of the tube should be from forty to forty-five
+centimeters. One end of the tube being softened in the flame is pressed
+against a block of wood so as to form a flange. Over this flange is
+tied a piece of fine linen.<a id="FNanchor_82" href="#Footnote_82" class="fnanchor">[82]</a></p>
+
+<p>Instead of using a linen diaphragm the tube is greatly improved, as
+suggested by Knorr, by sealing into the end of the tube while hot a
+<span class="pagenum"><a id="Page_131"></a>[Pg 131]</span>
+perforated platinum disk. Before using, the tube is dipped into a
+vessel containing some suspended asbestos felt and by aspiration a thin
+felt of asbestos is formed over the outer surface of the platinum disk.
+By inverting the tube the water which has entered during aspiration is
+removed. The tube thus prepared is dipped into the boiling solution in
+the test tube above described and aspiration continued until a drop of
+the liquor has entered the tube. It is then removed from the boiling
+solution, the asbestos felt wiped off with a clean towel, and the drop
+of liquor in the tube blown through the openings in the platinum disk
+and brought into contact with a drop of potassium ferrocyanid in the
+usual way. In this way a drop of the liquor is secured without any danger
+of a reoxidation of the copper which may sometimes take place on cooling.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_42" src="images/fig42.jpg" alt="" width="600" height="278" >
+    <p class="center spb1">Figure 42. Apparatus for the Volumetric Estimation<br>
+                   of Reducing Sugars.</p>
+</div>
+
+<p>The careful analyst by working in this way with the volumetric method
+is able to secure highly accurate results. The apparatus used is shown
+in the accompanying illustration.</p>
+
+<p><b>119. Suppression of the Error Caused by the Action of the Alkali
+on Reducing Sugars.</b>—Three methods are proposed by Gaud for
+correcting or suppressing the error due to the action of the alkali
+upon reducing sugars. In the first place, the common method followed
+may be employed, depending upon the use of an alkaline copper solution
+of known composition and the employment of a reducing sugar solution of
+a strength varying between one-half and one per cent. The error which
+is introduced into such a reaction is a constant one and the solution
+<span class="pagenum"><a id="Page_132"></a>[Pg 132]</span>
+having been tested once for all against pure sugar is capable of giving
+fairly accurate results.</p>
+
+<p>In the second place, a table may be constructed in which the error is
+determined for sugar solutions for varying strengths, <i>viz.</i>, from
+one-tenth of one per cent to ten per cent. If <i>y</i> represent the
+error and <i>x</i> the exact percentage of reducing sugar present then
+the correction may be made by the following formula;</p>
+
+<p class="f110"><i>y</i> = - 0.00004801<i>x</i> + 0.02876359<i>x</i>².</p>
+
+<p>In order to use this formula in practice the percentage of reducing
+sugar obtained by the actual analysis must be introduced and may
+be represented by θ. The formula for correction then becomes
+0.02876<i>x</i>² - 1.000048<i>x</i> + θ = 0; whence the value of
+<i>x</i> is easily computed.</p>
+
+<p>In the third place, the error may be eliminated by substituting for an
+alkali which acts upon the glucose one which does not, <i>viz.</i>,
+ammonia. At the temperature of boiling water ammonia does not have any
+decomposing effect upon reducing sugars. It is important, however,
+that the reduction take place in an inert atmosphere in order to
+avoid the oxidation of the dissolved cuprous oxid and the temperature
+need not be carried beyond 80°. The end of the reaction can be easily
+distinguished in this case by the disappearance of the blue color. When
+one reaction is finished the copper may be completely reoxidized by
+conducting through it a current of air or oxygen for half an hour, when
+an additional quantity of ammonia may be added to supply any that may
+have evaporated, and a new reduction accomplished with exactly the same
+quantity of copper as was used in the first. The solution used by Gaud
+contains 36.65 grams of crystallized copper sulfate dissolved in water
+and the volume completed to one liter with ordinary aqueous
+ammonia.<a id="FNanchor_83" href="#Footnote_83" class="fnanchor">[83]</a></p>
+
+<p><b>120. Permanganate Process for the Estimation of Reducing
+Sugars.</b>—Dextrose, invert sugar, and other reducing sugars can also
+be determined with a fair degree of accuracy by an indirect volumetric
+process, in which a standard solution of potassium permanganate is used
+as the final reagent.<a id="FNanchor_84" href="#Footnote_84" class="fnanchor">[84]</a>
+The principle of the process is based upon the observation that two molecules
+<span class="pagenum"><a id="Page_133"></a>[Pg 133]</span>
+of dextrose reduce from an alkaline cupric tartrate solution five
+molecules of cuprous oxid. The five molecules of cuprous oxid thus
+precipitated when added to an acid solution of ferric sulfate, will
+change five molecules of the ferric sulfate to ten molecules of ferrous
+sulfate. The reaction is illustrated by the following equation:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">5Cu₂O<br>715 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">&nbsp; + &nbsp;</td>
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">5Fe₂(SO₄)₃<br>2000 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">&nbsp; + &nbsp;</td>
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">5H₂SO₄<br>490 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">&nbsp; <span class="fs_120">=</span> &nbsp;</td>
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">10CuSO₄<br>1595 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdc">&nbsp; + &nbsp;</td>
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">10FeSO₄<br>1520 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">&nbsp; + &nbsp;</td>
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">5H₂O<br>90 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The ten molecules of ferrous sulfate formed as indicated in the above
+reaction, are reoxidized to ferric sulfate by a set solution of
+potassium permanganate. This reaction is illustrated by the equation
+given below:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">10FeSO₄<br>1520 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">&nbsp;+&nbsp;</td>
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">K₂Mn₂O₈<br>316.2 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">&nbsp;+&nbsp;</td>
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">5H₂SO₄<br>784 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">&nbsp;<span class="fs_120">=</span>&nbsp;</td>
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">5Fe₂(SO₄)₂<br>2000 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdc">+&nbsp;</td>
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">2MnSO₄<br>302 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">&nbsp;+&nbsp;</td>
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">K₂SO₄<br>174.2 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">&nbsp;+&nbsp;</td>
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">8H₂O<br>144 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+   </tr>
+ </tbody>
+</table>
+
+
+<p>By the study of the above equations it is seen that two molecules
+of dextrose or other similar reducing sugar, are equivalent
+to one molecule of potassium permanganate, as is shown by the
+following equations:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">2C₆H₁₂O₆<br>360 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">&nbsp;=&nbsp;</td>
+
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">5Cu₂O<br>715 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">&nbsp;=&nbsp;</td>
+
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">10FeSO₄<br>1520 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">&nbsp;=&nbsp;</td>
+
+      <td class="tdc"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdc">K₂Mn₂O₈<br>316.2 parts</td>
+      <td class="tdc"><img src="images/cbr-3.jpg" alt="" width="16" height="57" ></td>
+   </tr>
+ </tbody>
+</table>
+
+<p>It is thus seen that 316.2 parts by weight of potassium permanganate
+are equivalent to 360 parts by weight of dextrose; or one part of
+permanganate corresponds to 1.1385 parts by weight of dextrose. If,
+therefore, the amount of permanganate required in the above reaction to
+restore the iron to the ferric condition, be multiplied by the factor
+mentioned above, the quotient will represent in weight the amount of
+dextrose which enters into the reaction. The standard solution of
+potassium permanganate should contain 4.392 grams of the salt in a
+liter. One cubic centimeter of this solution is equivalent to five
+milligrams of dextrose.</p>
+
+<p><b>121. Manipulation.</b>—The saccharine solution whose strength is to
+be determined should contain approximately about one per cent of sugar.
+<span class="pagenum"><a id="Page_134"></a>[Pg 134]</span>
+Of this solution ten cubic centimeters are placed in a porcelain dish
+together with a considerable excess of fehling solution. When no
+sucrose is present, the mixture may be heated to the temperature of
+boiling water and kept at that temperature for a few minutes until
+all the reducing sugar is oxidized. There should be enough of the
+copper solution used to maintain a strong blue coloration at the end
+of the reaction. A greater uniformity of results will be secured by
+using in all cases a considerable excess of the copper solution. When
+sucrose or other non-reducing sugars are present, the temperature of
+the reaction should not be allowed to exceed 80° and the heating may
+be continued somewhat longer. At this temperature the copper solution
+is absolutely without action on sucrose. The precipitated suboxid is
+allowed to settle, the supernatant liquid poured off through a filter
+and the suboxid washed thoroughly a number of times by decantation with
+hot water, the washings being poured through the filter. This process
+of washing is greatly facilitated by decanting the supernatant liquid
+from the porcelain dish first into a beaker and from this into a third
+beaker and so on until no suboxid is carried off. Finally the wash
+water is poured through a filter-paper bringing as little as possible
+of the suboxid onto the paper. The suboxid on the filter-paper and in
+the beakers is next dissolved in a solution of ferric sulfate made
+strongly acid with sulfuric; or in a sulfuric acid solution of ammonia
+ferric sulfate which is more easily obtained free from impurities than
+the ferric sulfate. When all is dissolved from the beakers the solution
+is poured upon the suboxid which still remains in the porcelain dish.
+When the solution is complete it is washed into a half liter flask and
+all the vessels which contain the suboxid are also thoroughly washed
+and the wash waters added to the same flask. The whole is rendered
+strongly acid with sulfuric and made up to a volume of half a liter.</p>
+
+<p>The process carried out as directed, when tested against pure sugar,
+gives good results, not varying from the actual content of the sugar
+by more than one-tenth per cent below or three-tenths above the true
+content. The distinct pink coloration imparted to the solution by the
+permanganate solution as soon as the iron is all oxidized to the ferric
+state marks sharply the end of the reaction. In this respect this
+<span class="pagenum"><a id="Page_135"></a>[Pg 135]</span>
+process is very much to be preferred to the usual volumetric processes
+depending upon the coloration produced with potassium ferrocyanid
+by a copper salt for distinguishing the end of the reaction. It is
+less convenient than the ordinary volumetric process by reason of the
+somewhat tedious method of washing the precipitated cuprous oxid. When
+a large number of analyses is to be made, however, the whole can be
+washed with no more expenditure of time than is required for a single
+sample. One analyst can, in this way, easily attend to fifty or a
+hundred determinations at a time.</p>
+
+<p>In the application of the permanganate method to the analysis of the
+juices of sugar cane and sorghum it is directed to take 100 cubic
+centimeters of the expressed juice and clarify by the addition of
+twenty-five cubic centimeters of basic lead acetate, diluted with
+water, containing enough of the lead acetate, however, to produce a
+complete clarification. It is not necessary to remove the excess of
+lead from the filtrate before the determination. Ten cubic centimeters
+of the filtrate correspond to eight cubic centimeters of the original
+juice. For percentage calculation the specific gravity of the original
+juice must be known. Before the addition of the alkaline copper
+solution, from fifty to seventy-five cubic centimeters of water should
+be added to the clarified sugar juice and the amount of fehling
+solution used in each case should be from fifty to seventy-five cubic
+centimeters. The heating at 75° should be continued for half an hour
+in order to insure complete reduction and oxidation of the sugar. The
+sucrose can also be estimated in the same juices by inverting five
+cubic centimeters of the clarified juice with five cubic centimeters
+of dilute hydrochloric acid, by heating for an hour at a temperature
+not above 90°. Before adding the acid for inversion, about 100 cubic
+centimeters of water should be poured over the five cubic centimeters
+of sugar solution. The washing of the suboxid and the estimation of the
+amount reduced are accomplished in the manner above described.</p>
+
+<p>This method has been extensively used in this laboratory and with very
+satisfactory results. The only practical objection which can be urged
+to it is in the time required for filtering. This fault is easily
+remedied by adopting the method of filtering through asbestos felt
+described in the next paragraph.
+<span class="pagenum"><a id="Page_136"></a>[Pg 136]</span></p>
+
+<p>For the sake of uniformity, however, the copper solution should
+be boiled for a few minutes before the addition of the sugar in
+order to expel all oxygen, the sugar solutions should be made with
+recently boiled water and the precipitation of the suboxid should be
+accomplished by heating for just thirty minutes at 75°. At the end of
+this time an equal volume of cold, recently boiled, water should be
+added and the filtration at once accomplished.</p>
+
+<p><b>122. Modified Permanganate Method.</b>—The permanganate method
+as used by Ewell, in this laboratory, is conducted as follows: After
+the precipitate is obtained, according to the directions given in the
+methods described, it is thoroughly washed with hot, recently boiled
+water, on a gooch. The asbestos, with as much of the precipitate as
+possible, is transferred to the beaker in which the precipitation was
+made, beaten up with from twenty-five to thirty cubic centimeters
+of hot, recently boiled water, and from fifty to seventy-five cubic
+centimeters of a saturated solution of ferric sulfate in twenty-five
+per cent sulfuric acid are added to the beaker and then poured through
+the crucible to dissolve the cuprous oxid remaining therein. If the
+precipitate be first beaten up with water as directed, so that no
+large lumps of it remain, there is no difficulty in dissolving the
+oxid in the ferric salt; while if any lumps of the oxid be allowed to
+remain there is great difficulty. After the solution is obtained, it is
+titrated with a solution of potassium permanganate of such a strength
+that each cubic centimeter is equivalent to 0.01 gram of copper.</p>
+
+<p>In triplicate determinations made by this method the precipitates
+obtained required after solution in the ferric salt, 28.7, 28.9, 28.6
+cubic centimeters of potassium permanganate solution, respectively.
+For the quantities taken this was equivalent to an average percentage
+of reducing sugars of 4.19. The percentage obtained by the gravimetric
+method was 4.26.</p>
+
+<p>The method seems to be sufficiently accurate for all ordinary purposes
+and is extremely rapid.</p>
+
+<p>The permanganate solution used should be standardized by means
+of metallic iron, but in ordinary work it is also recommended to
+standardize by check determinations of reducing sugars in the same
+sample by the gravimetric method.
+<span class="pagenum"><a id="Page_137"></a>[Pg 137]</span></p>
+
+<p><b>123. Determination of Reducing Sugar by the Specific Gravity of
+the Cuprous Oxid.</b>—Gaud proposes to determine the percentage of
+reducing sugar from the specific gravity of the cuprous oxid. The
+manipulation is carried out as follows:</p>
+
+<p>In a porcelain dish are placed fifty cubic centimeters of the alkaline
+copper solution and an equal quantity of water and the mixture
+maintained in ebullition for two or three minutes. The dish is then
+placed on a boiling water-bath and twenty-five cubic centimeters of a
+reducing sugar of approximately one per cent strength added at once.
+The reduction is thus secured at a temperature below 100°, which is an
+important consideration in securing the minimum decomposing effect of
+the alkali upon the sugar. The dish is kept upon the water-bath for
+about ten minutes when the reduction is complete and the supernatant
+liquor should still be intensely blue. The precipitate is washed by
+decantation with boiling water, taking care to avoid the loss of any
+of the cuprous oxid. The washing is continued until the wash waters
+are neutral to phenolphthalein. The cuprous oxid is then washed into a
+pyknometer of from twenty to twenty-five cubic centimeters capacity,
+the exact content of which has been previously determined at zero. It
+is filled with boiling water, the stopper inserted, and after cooling
+the flask is weighed. Let <i>P</i> be the weight of the pyknometer plus
+the liquid and the precipitate, the total volume of which is equal to
+the capacity of the flask at the temperature at which it was filled,
+that is <i>V</i>ₜ = <i>V</i>₀ [1 + 3β(<i>t</i>-<i>t</i>₀)].</p>
+
+<p>This formula is essentially that given in paragraph <b><a href="#P_51">51</a></b>, for
+calculating the volume of a pyknometer at any temperature, substituting
+for 3β, γ the cubical expansion of glass, <i>viz</i>., 0.000025.</p>
+
+<p>The specific gravity of the dry cuprous oxid is Δ = 5.881 and let the
+specific gravity of water at the temperature of filling, which can be
+taken from any of the tables of the density of water, be <i>d</i>.
+The total weight <i>p</i> of the precipitated suboxid may then be
+calculated by the following formula:</p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>P</i> = &nbsp;</td>
+      <td class="tdc bb" colspan="2"><i>P</i>-<i>V</i>ₜ <i>d</i></td>
+      <td class="tdl_wsp" rowspan="2">.</td>
+   </tr><tr>
+      <td class="tdl">1 -</td>
+      <td class="tdl bb">&nbsp;<i>d</i></td>
+   </tr><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdc">Δ</td>
+      <td class="tdl">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The density of water at 99°, which is about the mean temperature of
+<span class="pagenum"><a id="Page_138"></a>[Pg 138]</span>
+boiling water for laboratories in general, is 0.95934, and this may be
+taken as the weight of one cubic centimeter for purposes of calculation
+in the formula above.</p>
+
+<p>In order to obtain exact results, it is important that the weight
+<i>P</i> be reduced to a vacuum. The weight of cuprous oxid not varying
+proportionally to the weight of reducing sugar, it is necessary to
+prepare a table showing the principal numerical values of the two, in
+order to be able to calculate easily all the possible values, either
+directly from the table or by appropriate interpolations. Following are
+the chief values which are necessary for the calculation:</p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc">&nbsp; Milligrams &nbsp;<br>cuprous oxid.</th>
+      <th class="tdc">&nbsp; Milligrams &nbsp;<br>dextrose.</th>
+      <th class="tdc">&nbsp; Milligrams &nbsp;<br>cuprous oxid.</th>
+      <th class="tdc">&nbsp; Milligrams &nbsp;<br>dextrose.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">10</td>
+      <td class="tdc">&#8199;5.413</td>
+      <td class="tdc">100</td>
+      <td class="tdc">&#8199;46.221</td>
+   </tr><tr>
+      <td class="tdc">20</td>
+      <td class="tdc">&#8199;9.761</td>
+      <td class="tdc">200</td>
+      <td class="tdc">&#8199;91.047</td>
+   </tr><tr>
+      <td class="tdc">30</td>
+      <td class="tdc">14.197</td>
+      <td class="tdc">300</td>
+      <td class="tdc">138.842</td>
+   </tr><tr>
+      <td class="tdc">50</td>
+      <td class="tdc">23.036</td>
+      <td class="tdc">400</td>
+      <td class="tdc">188.928</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>It is claimed by the author that the above method is both simple and
+rapid and can be applied with an error of not more than one-thousandth
+if the corrections for temperature and pressure be rigorously
+applied.<a id="FNanchor_85" href="#Footnote_85" class="fnanchor">[85]</a></p>
+
+<p id="P_124"><b>124. The Copper Carbonate Process.</b>—While the copper solutions
+which have been mentioned in previous paragraphs have only a slight
+action on sucrose and dextrin yet on prolonged boiling even these
+bodies show a reducing effect due probably to a preliminary change in
+the sugar molecules whereby products analogous to dextrose or invert
+sugar are formed. In order to secure a reagent, to which the sugar not
+reducing alkaline copper solutions might be more resistant Soldaini has
+proposed to employ a liquor containing the copper as carbonate instead
+of as tartrate.<a id="FNanchor_86" href="#Footnote_86" class="fnanchor">[86]</a>
+This solution is prepared by adding to a solution of forty grams of
+copper sulfate one of equal strength of sodium carbonate. The resulting
+copper carbonate and hydroxid are collected on a filter, washed with
+cold water, and dried. The reaction which takes place is represented by
+the following formula:</p>
+
+<p class="f110">2CuSO₄ + 2Na₂CO₃ + H₂O =<br>
+<span class="ws8">CuCO₃ + CuO₂H₂ + 2Na₂SO₄ + CO₂.</span></p>
+
+<p>The dry precipitate obtained, which will weigh about fifteen grams, is
+<span class="pagenum"><a id="Page_139"></a>[Pg 139]</span>
+placed in a large flask with about 420 grams of potassium bicarbonate
+and 1400 cubic centimeters of water. The contents of the flask are
+heated on a steam-bath for several hours with occasional stirring
+until the evolution of carbon dioxid has ceased. During this time the
+liquid is kept at the same volume by the addition of water, or by
+attaching a reflux condenser to the flask. The potassium and copper
+compounds at the end of this time will be found dissolved and the
+resulting liquor will have a deep blue color. After filtration the
+solution is boiled for a few minutes and cooled to room temperature.
+The volume is then completed to two liters. A more direct method of
+preparing the solution, and one quite as effective, consists in adding
+the solution of the copper sulfate directly to the hot solution of
+potassium bicarbonate and heating and shaking the mixture until the
+copper carbonate formed is dissolved. After filtering the volume is
+made as above. The proportions of reagents employed are placed by
+Preuss at 15.8 grams of crystallized copper sulfate and 594 grams of
+potassium bicarbonate.<a id="FNanchor_87" href="#Footnote_87" class="fnanchor">[87]</a>
+The soldaini reagent is extremely sensitive and is capable of detecting
+as little as half a milligram of invert sugar. The presence of sucrose
+makes the reagent more delicate, and it is especially useful in
+determining the invert sugar arising during the progress of manufacture
+by the action of heat and melassigenic bodies on sucrose.</p>
+
+<p><b>125. The Analytical Process.</b>—As in the case of fehling solution
+a great many methods of conducting the analysis with the soldaini
+reagent have been proposed. The general principle of all these
+processes is the one already described for the alkaline copper tartrate
+solution, <i>viz.</i>, the addition of the reducing sugar solution to
+the boiling reagent, and the determination of the end of the reaction
+by the disappearance of the copper.<a id="FNanchor_88" href="#Footnote_88" class="fnanchor">[88]</a></p>
+
+<p>Practically, however, these methods have had no general application,
+and the use of the soldaini reagent has been confined chiefly to the
+determination of invert sugar in presence of a large excess of sucrose.
+For this purpose the sugar solution is not added until the blue color
+of the reagent has been destroyed, but on the other hand, the reagent
+has been used in excess, and the cuprous oxid formed collected and
+<span class="pagenum"><a id="Page_140"></a>[Pg 140]</span>
+weighed as metallic copper. The weight of the metallic copper found,
+multiplied by the factor 0.3546, gives the weight of invert sugar in
+the volume of the sugar solution used. According to Preuss, the factor
+is not a constant one, but varies with the quantity of invert sugar
+present, as is seen in the formula <i>y</i> = 2.2868 + 3.3<i>x</i> +
+0.0041<i>x</i>², in which <i>x</i> = the invert sugar, and <i>y</i> the
+metallic copper.<a id="FNanchor_89" href="#Footnote_89" class="fnanchor">[89]</a></p>
+
+<p><b>126. Tenth Normal Copper Carbonate Solution.</b>—In the study of
+some of the solutions of copper carbonate, proposed for practical
+work, Ettore Soldaini was impressed with the difficulty of dissolving
+so large a quantity of carbonate in the solvent employed.<a id="FNanchor_90" href="#Footnote_90" class="fnanchor">[90]</a>
+The solution recommended by Bodenbender and Scheller,<a id="FNanchor_91" href="#Footnote_91" class="fnanchor">[91]</a>
+in which forty grams of the crystallized copper sulfate were used,
+failed to disclose an equivalent amount of copper in the reagent ready
+for use. For this reason a tenth-normal copper solution is prepared by
+Soldaini containing the equivalent of 3.464 grams of copper sulfate
+in one liter. The reagent is easily prepared by adding slowly the
+dissolved or finely powdered copper salt to a solution of 297 grams
+of potassium bicarbonate, and after complete solution of the copper
+carbonate formed, completing the volume to one liter. With this reagent
+as little as one-quarter of a milligram of reducing sugar can be easily
+detected. For the quantitive estimation of sugar a solution of the
+above strength is to be preferred to the other forms of the soldaini
+reagent by reason of the ease of direct comparison with standard
+fehling solutions.</p>
+
+<p>The analytical process is conducted with the tenth-normal solution,
+prepared by Soldaini and described above, as follows: Place 100 cubic
+centimeters of the reagent in each of several porcelain dishes heat
+to boiling, and add little by little the sugar solution to one dish
+until the blue color has disappeared. Having thus determined nearly the
+exact quantity of sugar solution required for the copper in 100 cubic
+centimeters of the reagent the whole of the sugar solution is added at
+once, varying slightly the amounts added to each dish. The boiling is
+continued for fifteen minutes, and the contents of the dishes poured
+on filters. That filtrate which contains neither copper nor sugar
+represents the exact quantity of sugar solution which contained fifty
+milligrams of dextrose.
+<span class="pagenum"><a id="Page_141"></a>[Pg 141]</span></p>
+
+<p><b>127. Relation of Reducing Sugar to Quantity of Copper Suboxid
+Obtained.</b>—The relation of the quantity of copper reduced to
+the amount of sugar oxidized by the copper carbonate solution has
+been determined by Ost, and the utility of the process thereby
+increased.<a id="FNanchor_92" href="#Footnote_92" class="fnanchor">[92]</a>
+The solution used should have the following composition: 23.5 grams
+of crystallized copper sulfate, 250 grams of potassium carbonate, and
+100 grams of potassium bicarbonate in one liter. Without an indicator
+the end reaction is distinctly marked by the passage of the blue color
+into a colorless solution. Ost affirms that this solution is preferable
+to any form of fehling liquor because it can be kept indefinitely
+unchanged; it attacks sucrose far less strongly, and an equal quantity
+of sugar precipitates nearly double the quantity of copper. The boiling
+requires a longer time, as a rule ten minutes, but this is a matter of
+no importance, when the other advantages are taken into consideration.
+The relations of the different sugars to the quantity of copper
+precipitated are given in the table in the next paragraph.</p>
+
+<p id="P_128"><b>128. Factor for Different Sugars.</b>—For pure dextrose the
+relation between sugar and copper reduced has been determined by
+Ost, and the data are given in the table below. The data were
+obtained by adding to fifty cubic centimeters of the copper solution
+twenty-five cubic centimeters of sugar solutions of varying strength
+and collecting, washing, and reducing the cuprous oxid obtained in a
+current of hydrogen in a glass tube by the method described further on.</p>
+
+<p>The boiling in all cases was continued, just ten minutes, although a
+slight variation from the standard time did not produce so great a
+difference as with fehling reagent. In the case of dextrose, when fifty
+milligrams were used with fifty cubic centimeters of the solution,
+the milligrams of copper obtained after six, ten and twenty minutes’
+boiling were 164.6, 165.5, and 166.9 respectively.<a id="FNanchor_93" href="#Footnote_93" class="fnanchor">[93]</a></p>
+
+<p>The data differ considerably from those obtained by Herzfeld, but
+in his experiments the boiling was continued only for five minutes,
+<span class="pagenum"><a id="Page_142"></a>[Pg 142]</span>
+and this is not long enough to secure the proper reduction of the
+copper.<a id="FNanchor_94" href="#Footnote_94" class="fnanchor">[94]</a></p>
+
+<p class="f120 spa1"><b><span class="smcap">Table Showing the Quantity of Copper<br>
+Reduced by Different Sugars.</span></b></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb">Copper.<br>&nbsp;Milligrams&nbsp;</th>
+      <th class="tdc bb">Invert Sugar.<br>&nbsp;Milligrams&nbsp;</th>
+      <th class="tdc bb">Dextrose.<br>&nbsp;Milligrams&nbsp;</th>
+      <th class="tdc bb">Levulose.<br>&nbsp;Milligrams&nbsp;</th>
+      <th class="tdc bb">Galactose.<br>&nbsp;Milligrams&nbsp;</th>
+      <th class="tdc bb">Arabinose.<br>&nbsp;Milligrams</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">&#8199;50</td>
+      <td class="tdc">15.2</td>
+      <td class="tdc">15.6</td>
+      <td class="tdc">14.7</td>
+      <td class="tdc">17.4</td>
+      <td class="tdc">17.0</td>
+   </tr><tr>
+      <td class="tdc">&#8199;55</td>
+      <td class="tdc">16.6</td>
+      <td class="tdc">17.0</td>
+      <td class="tdc">16.1</td>
+      <td class="tdc">19.1</td>
+      <td class="tdc">18.6</td>
+   </tr><tr>
+      <td class="tdc">&#8199;60</td>
+      <td class="tdc">18.0</td>
+      <td class="tdc">18.5</td>
+      <td class="tdc">17.5</td>
+      <td class="tdc">20.8</td>
+      <td class="tdc">20.3</td>
+   </tr><tr>
+      <td class="tdc">&#8199;65</td>
+      <td class="tdc">19.4</td>
+      <td class="tdc">19.9</td>
+      <td class="tdc">18.9</td>
+      <td class="tdc">22.5</td>
+      <td class="tdc">21.9</td>
+   </tr><tr>
+      <td class="tdc">&#8199;70</td>
+      <td class="tdc">20.8</td>
+      <td class="tdc">21.4</td>
+      <td class="tdc">20.3</td>
+      <td class="tdc">24.2</td>
+      <td class="tdc">23.5</td>
+   </tr><tr>
+      <td class="tdc">&#8199;75</td>
+      <td class="tdc">22.3</td>
+      <td class="tdc">22.9</td>
+      <td class="tdc">21.7</td>
+      <td class="tdc">25.9</td>
+      <td class="tdc">25.1</td>
+   </tr><tr>
+      <td class="tdc">&#8199;80</td>
+      <td class="tdc">23.7</td>
+      <td class="tdc">24.4</td>
+      <td class="tdc">23.0</td>
+      <td class="tdc">27.7</td>
+      <td class="tdc">26.7</td>
+   </tr><tr>
+      <td class="tdc">&#8199;85</td>
+      <td class="tdc">25.2</td>
+      <td class="tdc">25.8</td>
+      <td class="tdc">24.3</td>
+      <td class="tdc">29.3</td>
+      <td class="tdc">28.3</td>
+   </tr><tr>
+      <td class="tdc">&#8199;90</td>
+      <td class="tdc">26.6</td>
+      <td class="tdc">27.3</td>
+      <td class="tdc">25.7</td>
+      <td class="tdc">31.1</td>
+      <td class="tdc">29.9</td>
+   </tr><tr>
+      <td class="tdc bb">&#8199;95</td>
+      <td class="tdc bb">28.1</td>
+      <td class="tdc bb">28.8</td>
+      <td class="tdc bb">27.1</td>
+      <td class="tdc bb">32.8</td>
+      <td class="tdc bb">31.5</td>
+   </tr><tr>
+      <td class="tdc">100</td>
+      <td class="tdc">29.5</td>
+      <td class="tdc">30.3</td>
+      <td class="tdc">28.5</td>
+      <td class="tdc">34.5</td>
+      <td class="tdc">33.1</td>
+   </tr><tr>
+      <td class="tdc">105</td>
+      <td class="tdc">31.0</td>
+      <td class="tdc">31.8</td>
+      <td class="tdc">29.9</td>
+      <td class="tdc">36.2</td>
+      <td class="tdc">34.7</td>
+   </tr><tr>
+      <td class="tdc">110</td>
+      <td class="tdc">32.4</td>
+      <td class="tdc">33.3</td>
+      <td class="tdc">31.2</td>
+      <td class="tdc">38.0</td>
+      <td class="tdc">36.3</td>
+   </tr><tr>
+      <td class="tdc">115</td>
+      <td class="tdc">33.9</td>
+      <td class="tdc">34.8</td>
+      <td class="tdc">32.6</td>
+      <td class="tdc">39.7</td>
+      <td class="tdc">37.9</td>
+   </tr><tr>
+      <td class="tdc">120</td>
+      <td class="tdc">35.3</td>
+      <td class="tdc">36.3</td>
+      <td class="tdc">34.0</td>
+      <td class="tdc">41.4</td>
+      <td class="tdc">39.5</td>
+   </tr><tr>
+      <td class="tdc">125</td>
+      <td class="tdc">36.8</td>
+      <td class="tdc">37.8</td>
+      <td class="tdc">35.4</td>
+      <td class="tdc">43.1</td>
+      <td class="tdc">41.1</td>
+   </tr><tr>
+      <td class="tdc">130</td>
+      <td class="tdc">38.2</td>
+      <td class="tdc">39.3</td>
+      <td class="tdc">36.8</td>
+      <td class="tdc">44.8</td>
+      <td class="tdc">42.8</td>
+   </tr><tr>
+      <td class="tdc">135</td>
+      <td class="tdc">39.7</td>
+      <td class="tdc">40.8</td>
+      <td class="tdc">38.2</td>
+      <td class="tdc">46.5</td>
+      <td class="tdc">44.4</td>
+   </tr><tr>
+      <td class="tdc">140</td>
+      <td class="tdc">41.1</td>
+      <td class="tdc">42.3</td>
+      <td class="tdc">39.6</td>
+      <td class="tdc">48.3</td>
+      <td class="tdc">46.0</td>
+   </tr><tr>
+      <td class="tdc bb">145</td>
+      <td class="tdc bb">42.6</td>
+      <td class="tdc bb">43.8</td>
+      <td class="tdc bb">41.0</td>
+      <td class="tdc bb">50.0</td>
+      <td class="tdc bb">47.6</td>
+   </tr><tr>
+      <td class="tdc">150</td>
+      <td class="tdc">44.0</td>
+      <td class="tdc">45.3</td>
+      <td class="tdc">42.5</td>
+      <td class="tdc">51.8</td>
+      <td class="tdc">49.3</td>
+   </tr><tr>
+      <td class="tdc">155</td>
+      <td class="tdc">45.5</td>
+      <td class="tdc">46.8</td>
+      <td class="tdc">43.9</td>
+      <td class="tdc">53.6</td>
+      <td class="tdc">50.9</td>
+   </tr><tr>
+      <td class="tdc">160</td>
+      <td class="tdc">47.0</td>
+      <td class="tdc">48.3</td>
+      <td class="tdc">45.3</td>
+      <td class="tdc">55.4</td>
+      <td class="tdc">52.6</td>
+   </tr><tr>
+      <td class="tdc">165</td>
+      <td class="tdc">48.5</td>
+      <td class="tdc">49.8</td>
+      <td class="tdc">46.7</td>
+      <td class="tdc">57.2</td>
+      <td class="tdc">54.3</td>
+   </tr><tr>
+      <td class="tdc">170</td>
+      <td class="tdc">50.0</td>
+      <td class="tdc">51.4</td>
+      <td class="tdc">48.1</td>
+      <td class="tdc">59.0</td>
+      <td class="tdc">55.9</td>
+   </tr><tr>
+      <td class="tdc">175</td>
+      <td class="tdc">51.5</td>
+      <td class="tdc">52.9</td>
+      <td class="tdc">49.5</td>
+      <td class="tdc">60.8</td>
+      <td class="tdc">57.5</td>
+   </tr><tr>
+      <td class="tdc">180</td>
+      <td class="tdc">53.0</td>
+      <td class="tdc">54.5</td>
+      <td class="tdc">51.0</td>
+      <td class="tdc">62.7</td>
+      <td class="tdc">59.2</td>
+   </tr><tr>
+      <td class="tdc">185</td>
+      <td class="tdc">54.5</td>
+      <td class="tdc">56.0</td>
+      <td class="tdc">52.5</td>
+      <td class="tdc">64.5</td>
+      <td class="tdc">60.9</td>
+   </tr><tr>
+      <td class="tdc">190</td>
+      <td class="tdc">56.0</td>
+      <td class="tdc">57.6</td>
+      <td class="tdc">54.0</td>
+      <td class="tdc">66.4</td>
+      <td class="tdc">62.7</td>
+   </tr><tr>
+      <td class="tdc bb">195</td>
+      <td class="tdc bb">57.5</td>
+      <td class="tdc bb">59.2</td>
+      <td class="tdc bb">55.5</td>
+      <td class="tdc bb">68.3</td>
+      <td class="tdc bb">64.4</td>
+   </tr><tr>
+      <td class="tdc">200</td>
+      <td class="tdc">59.1</td>
+      <td class="tdc">60.8</td>
+      <td class="tdc">57.0</td>
+      <td class="tdc">70.3</td>
+      <td class="tdc">66.2</td>
+   </tr><tr>
+      <td class="tdc">205</td>
+      <td class="tdc">60.7</td>
+      <td class="tdc">62.4</td>
+      <td class="tdc">58.6</td>
+      <td class="tdc">72.3</td>
+      <td class="tdc">68.0</td>
+   </tr><tr>
+      <td class="tdc">210</td>
+      <td class="tdc">62.4</td>
+      <td class="tdc">64.1</td>
+      <td class="tdc">60.2</td>
+      <td class="tdc">74.3</td>
+      <td class="tdc">69.8</td>
+   </tr><tr>
+      <td class="tdc">215</td>
+      <td class="tdc">64.1</td>
+      <td class="tdc">65.8</td>
+      <td class="tdc">61.8</td>
+      <td class="tdc">76.3</td>
+      <td class="tdc">71.6</td>
+   </tr><tr>
+      <td class="tdc">220</td>
+      <td class="tdc">65.8</td>
+      <td class="tdc">67.5</td>
+      <td class="tdc">63.5</td>
+      <td class="tdc">78.3</td>
+      <td class="tdc">73.5</td>
+   </tr><tr>
+      <td class="tdc">225</td>
+      <td class="tdc">67.5</td>
+      <td class="tdc">69.2</td>
+      <td class="tdc">65.2</td>
+      <td class="tdc">80.3</td>
+      <td class="tdc">75.4</td>
+   </tr><tr>
+      <td class="tdc">230</td>
+      <td class="tdc">69.3</td>
+      <td class="tdc">70.9</td>
+      <td class="tdc">66.9</td>
+      <td class="tdc">82.4</td>
+      <td class="tdc">77.3</td>
+   </tr><tr>
+      <td class="tdc">235</td>
+      <td class="tdc">71.1</td>
+      <td class="tdc">72.7</td>
+      <td class="tdc">68.7</td>
+      <td class="tdc">84.5</td>
+      <td class="tdc">79.3</td>
+   </tr><tr>
+      <td class="tdc">240</td>
+      <td class="tdc">72.9</td>
+      <td class="tdc">74.5</td>
+      <td class="tdc">70.6</td>
+      <td class="tdc">86.6</td>
+      <td class="tdc">81.3</td>
+   </tr><tr>
+      <td class="tdc bb">245</td>
+      <td class="tdc bb">74.8</td>
+      <td class="tdc bb">76.4</td>
+      <td class="tdc bb">72.5</td>
+      <td class="tdc bb">88.9</td>
+      <td class="tdc bb">83.4</td>
+   </tr><tr>
+      <td class="tdc">250</td>
+      <td class="tdc">76.7</td>
+      <td class="tdc">78.4</td>
+      <td class="tdc">74.4</td>
+      <td class="tdc">91.2</td>
+      <td class="tdc">85.5</td>
+   </tr><tr>
+      <td class="tdc">255</td>
+      <td class="tdc">78.6</td>
+      <td class="tdc">80.5</td>
+      <td class="tdc">76.5</td>
+      <td class="tdc">93.5</td>
+      <td class="tdc">87.6</td>
+   </tr><tr>
+      <td class="tdc">260</td>
+      <td class="tdc">80.5</td>
+      <td class="tdc">82.8</td>
+      <td class="tdc">78.8</td>
+      <td class="tdc">95.9</td>
+      <td class="tdc">89.8</td>
+   </tr><tr>
+      <td class="tdc">265</td>
+      <td class="tdc">82.5</td>
+      <td class="tdc">85.1</td>
+      <td class="tdc">81.1</td>
+      <td class="tdc">98.3</td>
+      <td class="tdc">92.2</td>
+   </tr><tr>
+      <td class="tdc">270</td>
+      <td class="tdc">84.7</td>
+      <td class="tdc">87.5</td>
+      <td class="tdc">83.5</td>
+      <td class="tdc">100.7&#8199;</td>
+      <td class="tdc">94.6</td>
+   </tr><tr>
+      <td class="tdc">275</td>
+      <td class="tdc">87.1</td>
+      <td class="tdc">89.9</td>
+      <td class="tdc">85.9</td>
+      <td class="tdc">103.3&#8199;</td>
+      <td class="tdc">97.1</td>
+   </tr><tr>
+      <td class="tdc">280</td>
+      <td class="tdc">89.7</td>
+      <td class="tdc">92.4</td>
+      <td class="tdc">88.6</td>
+      <td class="tdc">106.1&#8199;</td>
+      <td class="tdc">99.6</td>
+   </tr><tr>
+      <td class="tdc">285</td>
+      <td class="tdc">92.3</td>
+      <td class="tdc">94.9</td>
+      <td class="tdc">91.3</td>
+      <td class="tdc">109.0&#8199;</td>
+      <td class="tdc">102.3&#8199;</td>
+   </tr><tr>
+      <td class="tdc">290</td>
+      <td class="tdc">95.1</td>
+      <td class="tdc">97.6</td>
+      <td class="tdc">94.2</td>
+      <td class="tdc">112.0&#8199;</td>
+      <td class="tdc">105.1&#8199;</td>
+   </tr><tr>
+      <td class="tdc">295</td>
+      <td class="tdc">98.0</td>
+      <td class="tdc">100.4&#8199;</td>
+      <td class="tdc">97.2</td>
+      <td class="tdc">115.1&#8199;</td>
+      <td class="tdc">107.9&#8199;</td>
+   </tr><tr>
+      <td class="tdc">298</td>
+      <td class="tdc">100.0&#8199;</td>
+      <td class="tdc">102.5&#8199;</td>
+      <td class="tdc">99.0</td>
+      <td class="tdc">117.0&#8199;</td>
+      <td class="tdc">109.5&#8199;</td>
+   </tr>
+ </tbody>
+</table>
+<p class="spa2"><span class="pagenum"><a id="Page_143"></a>[Pg 143]</span></p>
+
+<h3>VOLUMETRIC METHODS<br> BASED UPON THE USE OF AN<br> AMMONIACAL COPPER SOLUTION.</h3>
+
+<p><b>129. Pavy’s Process.</b>—The well-known solubility of cuprous oxid
+in ammonia led Pavy to adopt a copper reagent containing ammonia in the
+volumetric determination of reducing sugars.<a id="FNanchor_95" href="#Footnote_95" class="fnanchor">[95]</a> In Pavy’s process an
+alkaline copper solution is employed made up in the usual way, to which
+a sufficient quantity of ammonia is added to hold in solution all the
+copper when precipitated as cuprous oxid. The solution used by Pavy has
+the following composition: One liter contains</p>
+
+<table class="spb2">
+   <tbody><tr>
+      <td class="tdl">Crystallized copper sulfate&emsp;&nbsp;</td>
+      <td class="tdr">34.65</td>
+      <td class="tdl_wsp">grams</td>
+   </tr><tr>
+      <td class="tdl">Potassium-sodium tartrate</td>
+      <td class="tdr">173.00</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl">Caustic potash</td>
+      <td class="tdr">160.00</td>
+      <td class="tdc">”</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>For use 120 cubic centimeters of the above reagent are mixed with 300
+of ammonia of specific gravity 0.88, and the volume completed to one
+liter with distilled water. Twenty cubic centimeters of this reagent
+are equivalent to ten milligrams of dextrose or invert sugar when added
+in a one per cent solution.</p>
+
+<p>In the use of ammoniacal copper solution, care must be taken that
+all the liquids employed be entirely free of oxygen and that the
+contents of the flask in which the reduction takes place be in some way
+excluded from contact with the air. Pavy secured this by conducting
+the reduction in a flask closed with a stopper carrying two holes;
+one of these served for the introduction of the burette carrying the
+sugar solution and the other carried a tube dipping into a water seal
+by means of a slit rubber tube, which would permit of the exit of the
+vapors of steam and ammonia, but prevent the regurgitation of the water
+into the flask.</p>
+
+<p>The complete decoloration of the copper solution marks the end of the
+reaction. The usual precautions in regard to the length of the time of
+boiling must be observed.</p>
+
+<p>It is easy to see that in the Pavy process the quantity of ammonia in
+the solution is rapidly diminished during the boiling and this has led
+to the suggestion of other methods to exclude the air. Among these have
+been recommended the introduction of a current of hydrogen or carbon
+dioxid. One of the best methods of procedure is that proposed by Allen,
+<span class="pagenum"><a id="Page_144"></a>[Pg 144]</span>
+who recommends covering the copper solution by a layer of paraffin oil
+(kerosene).<a id="FNanchor_96" href="#Footnote_96" class="fnanchor">[96]</a></p>
+
+<p><b>130. Process Of Peska.</b>—Peska has also independently made use of
+Allen’s method of covering the solutions with a layer of paraffin oil
+and finds it reliable.<a id="FNanchor_97" href="#Footnote_97" class="fnanchor">[97]</a>
+The copper reagent employed by him has the following composition:</p>
+
+<table class="spb2">
+   <tbody><tr>
+      <td class="tdl">Crystallized copper sulfate</td>
+      <td class="tdr">6.927</td>
+      <td class="tdl_wsp">grams</td>
+   </tr><tr>
+      <td class="tdl">Ammonia, twenty-five per cent strength&emsp;&nbsp;</td>
+      <td class="tdr">160.00&#8199;</td>
+      <td class="tdl_wsp">cc.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The copper sulfate is dissolved in water, the ammonia added, and
+the volume completed to half a liter with distilled water. A second
+solution containing half a liter is made by dissolving 34.5 grams
+of potassium-sodium tartrate and ten grams of sodium hydroxid and
+completing the cool solution to half a liter with distilled water.
+In all cases the water used in making up the above solutions must be
+freshly boiled to exclude the air.</p>
+
+<p>For the titration, fifty cubic centimeters of each of the above
+solutions are taken, mixed and covered with a layer of paraffin oil
+half a centimeter in depth. The reduction is not accomplished at a
+boiling temperature, but at from 80° to 85°. The manipulation is
+conducted as follows:</p>
+
+<p>The mixed solutions are placed in a beaker, covered with oil, and
+heated to 80°. The temperature is measured by a thermometer which also
+serves as a stirring rod. The sugar solution is run down the sides
+of the beaker from a burette of such a shape as to be protected from
+the heat. After each addition of the sugar solution the mixture is
+carefully stirred, keeping the temperature at from 80° to 85°. The
+first titration is made to determine approximately the quantity of
+sugar solution necessary to decolorize the copper. This done, the
+actual titration is accomplished by adding at once the total amount
+of sugar solution necessary to decolorize, less about one cubic
+centimeter. Any sugar solution adhering to the side of the beaker
+is washed down by distilled water, the contents of the beaker well
+stirred, and the temperature kept at 85° for two minutes. The rest of
+the sugar solution is then added in quantities of one-tenth of a cubic
+centimeter until the decoloration is completed. The total time of the
+final titration should not exceed five minutes. The sugar solution
+should be as nearly as possible of one per cent strength. If a lower
+<span class="pagenum"><a id="Page_145"></a>[Pg 145]</span>
+degree of strength be employed a larger quantity of the sugar is
+necessary to reduce a given quantity of copper.</p>
+
+<p>In the case of dextrose, when a one per cent solution is used, eight
+and two-tenths cubic centimeters, corresponding to 80.2 milligrams of
+dextrose, are required to reduce 100 cubic centimeters of the mixed
+reagent. On the other hand, when the sugar solution is diluted to
+one-tenth of a per cent strength 82.1 milligrams are required.</p>
+
+<p>With invert sugar slightly larger quantities are necessary, the
+reducing power being as 94.9 to 100 as compared with dextrose. With
+a one per cent strength of invert sugar it is found that eighty-four
+milligrams are required to reduce 100 cubic centimeters of the mixed
+reagent and when the strength of the invert sugar is reduced to
+one-tenth per cent 87.03 milligrams are required.</p>
+
+<p><b>131. Method Of Allein and Gaud.</b>—Allein and Gaud have proposed a
+further modification of the ammonia process which consists essentially
+in the suppression of rochelle salt and fixed caustic alkali and the
+entire substitution therefor of ammonia. Ammonia acts with much less
+vigor upon sugars than the caustic alkalies, and it is therefore
+claimed that the decomposition of the sugar due to the alkali is
+reduced to a minimum when ammonia is employed.<a id="FNanchor_98" href="#Footnote_98" class="fnanchor">[98]</a>
+The copper solution is made as follows:</p>
+
+<p>Dissolve 8.7916 grams of electrolytic copper in ninety-three grams
+of concentrated sulfuric acid diluted with an equal volume of water.
+Complete the resulting solution to one liter with concentrated ammonia.
+Ten cubic centimeters of this solution are equal to fifty grams of
+dextrose.</p>
+
+<p>It is recommended that the reduction be accomplished in an atmosphere
+of hydrogen, but it is apparent that the use of kerosene is permissible
+in this case, and on account of its greater simplicity it is to be
+recommended as the best means of excluding the oxygen. The reduction is
+accomplished at a temperature of about 80°.</p>
+
+<p>It is also proposed to reoxidize the copper by substituting a current
+of air for the hydrogen at the end of the reaction, and thus use the
+same copper a number of times. The danger of loss of ammonia, and the
+<span class="pagenum"><a id="Page_146"></a>[Pg 146]</span>
+difficulty of determining when the oxidation is complete, render this
+regeneration of the reagent undesirable.</p>
+
+<p><b>132. Method of Gerrard.</b>—The method of Gerrard does not depend
+upon the use of ammonia, but the principle involved is the same,
+<i>viz.</i>, the holding of the separated cuprous oxid in solution
+and the determination of the end of the reaction by the disappearance
+of the blue color. As first proposed by Gerrard, the copper sulfate
+solution is made of double the strength usually employed and to each
+100 cubic centimeters thereof, before use, three and three-tenths
+grams of potassium cyanid are added. This is sufficient to hold the
+precipitated cuprous oxid in solution.<a id="FNanchor_99" href="#Footnote_99" class="fnanchor">[99]</a></p>
+
+<p>The original method of Gerrard is found difficult of execution and the
+author, in conjunction with Allen, has lately modified it and reduced
+it to a practical working basis.<a id="FNanchor_100" href="#Footnote_100" class="fnanchor">[100]</a></p>
+
+<p>In the new method the ordinary fehling solution is employed and it
+is prepared for use in the following way: Ten cubic centimeters of
+the fehling solution, or half that quantity of each of the component
+parts kept in separate bottles, are placed in a porcelain dish with
+forty cubic centimeters of water and brought to the boiling-point. To
+the boiling liquid is added, from a pipette, a five per cent solution
+of potassium cyanid until the blue color just disappears, or only a
+very faint tint of blue remains, avoiding any excess of the cyanid. A
+second portion of the fehling solution equal to that first employed
+is added, and to the boiling mixture the solution of sugar is added,
+from a burette, until the blue color disappears. The contents of the
+dish should be kept boiling during the addition of the sugar solution.
+The volume used will contain fifty milligrams of dextrose. The sugar
+solution should be of such a strength as to contain no more than half a
+per cent of reducing sugar.</p>
+
+<p>The principle of the preparation of the solution may be stated as
+follows: If to a solution of copper sulfate, potassium be added until
+the blue color disappears, a double cyanid of copper and potassium
+cyanid is formed according to the following reaction:</p>
+
+<p class="f110">CuSO₄ + 4KCN = Cu(CN)₂.2KCN + K₂SO₄.</p>
+
+<p class="no-indent">This double cyanid is a salt of considerable
+stability. It is not decomposed by alkalies, hydrogen or ammonium,
+<span class="pagenum"><a id="Page_147"></a>[Pg 147]</span>
+sulfid. With mineral acids it gives a whitish, curdy precipitate. With
+fehling solution the same double cyanid is formed as that described
+above. If, however, fehling solution be present in excess of the amount
+necessary to form the double cyanid of copper, this excess can be used
+in the oxidation of reducing sugar and the colorless condition of the
+solution will be restored as soon as the excess of the fehling is
+destroyed. The double cyanid holds in solution the cuprous oxid formed
+and thus complete decoloration is secured.</p>
+
+<p><b>133. Sidersky’s Modification of Soldaini’s Process.</b>—In all
+cases where the sugar solutions are not too highly colored, Sidersky
+finds that the method of reduction in a large test tube, as practiced
+by Violette, is applicable with the copper carbonate solution.<a id="FNanchor_101" href="#Footnote_101" class="fnanchor">[101]</a>
+For more exact work it is preferred to determine the quantity of copper
+reduced by an indirect volumetric method. The sugar solution, properly
+clarified and the lead removed if subacetates have been used, is made
+of such a volume as to contain less than one per cent of reducing
+sugars. In a flask or large test tube are placed 100 cubic centimeters
+of the copper solution, which is boiled for a short time and the sugar
+solution added, little by little, from a pipette, at such a rate as
+not to stop the ebullition. The boiling is continued for five minutes
+after the last addition of the sugar. The vessel is taken from the
+flame and 100 cubic centimeters of cold water added, the whole brought
+on an asbestos felt and the cuprous oxid washed with hot water until
+the alkaline reaction has disappeared. The residual cuprous oxid
+is dissolved in a measured quantity of set sulfuric acid, semi- or
+fifth-normal, a few particles of potassium chlorate added, and the
+mixture boiled to convert any cuprous into cupric sulfate. The reaction
+is represented by the following formula:</p>
+
+<p class="f110">3Cu₂O + 6H₂SO₄ + KClO₃ = 6CuSO₄ + KCl + 6H₂O.</p>
+
+<p>The residual sulfuric acid is titrated with a set alkali in excess,
+ammonia being preferred.</p>
+
+<p>The solution of ammonia is made by diluting 200 cubic centimeters of
+commercial aqua ammonia with 800 of water. Its strength is determined
+by adding a little copper sulfate solution as indicator and then the
+set solution of sulfuric acid until the blue color disappears. The
+<span class="pagenum"><a id="Page_148"></a>[Pg 148]</span>
+copper sulfate secured from the cuprous sulfate as described above
+is cooled, and a quantity of the ammonia, equal to twenty-five cubic
+centimeters of the set sulfuric acid, added. The excess of the
+ammonia is then determined by titration with the sulfuric acid, the
+disappearance of the blue color being the indication of the end of the
+reaction. The number of cubic centimeters of the set sulfuric acid
+required to saturate the ammonia represents the equivalent of cuprous
+oxid originally present. One cubic centimeter of normal sulfuric acid
+is equivalent to 0.0317 gram of metallic copper.</p>
+
+<p>To determine the weight of invert sugar oxidized, multiply the weight
+of copper, calculated as above described, by the factor 0.3546.<a id="FNanchor_102" href="#Footnote_102" class="fnanchor">[102]</a>
+For a general application of this method of analysis the relative
+quantities of copper reduced by different quantities of sugar must be
+taken into consideration.</p>
+
+<p>While, as has already been stated, the copper carbonate process has
+heretofore been applied chiefly to the detection of invert sugar, it
+has merits which justify the expectation that it may some time supplant
+the fehling liquor both for volumetric and gravimetric work. Large
+volumes of the reagent can be prepared at once and without danger of
+subsequent change. The action of the reagent on the hexobioses and
+trioses is far less vigorous than that of the alkaline copper tartrate,
+and the end reactions for volumetric work are, at least, as easily
+determined in the one case as the other.</p>
+
+<p><b>134. Method Depending on Titration of Excess of Copper.</b>—Instead
+of measuring the quantity of copper reduced, either by its
+disappearance or by reducing the cuprous oxid to a metallic state,
+Politis has proposed a method of analysis depending on the titration of
+the residual copper.<a id="FNanchor_103" href="#Footnote_103" class="fnanchor">[103]</a>
+The reagents employed are:</p>
+
+<div class="blockquot">
+<p>(1) A copper solution containing 24.95 grams of crystallized copper
+sulfate, 140 grams of sodium and potassium tartrate, and twenty-five
+grams of sodium hydroxid in one liter:</p>
+
+<p>(2) A solution of sodium thiosulfate containing 24.8 grams of the salt
+in one liter:</p>
+
+<p>(3) A solution of potassium iodid containing 12.7 grams of iodin in one
+liter.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_149"></a>[Pg 149]</span>
+The reaction is represented by the formula</p>
+
+<p class="f110">2CuCl₂ + 4KI = Cu₂I₂ + 4KCl + I₂.</p>
+
+<p>The analytical process is carried out as follows: In a 100 cubic
+centimeter flask are boiled fifty cubic centimeters of the copper
+solution, ten cubic centimeters of about one-tenth per cent reducing
+sugar solution are added, the boiling continued for five minutes,
+the flask filled to the mark with boiling water and its contents
+filtered. Fifty cubic centimeters of the hot filtrate are cooled,
+slightly acidified, potassium iodid solution added in slight excess;
+and the iodin set free determined by titration with sodium thiosulfate.
+The quantity of iodin obtained corresponds to the unreduced copper
+remaining after treatment with the reducing sugar. The number of cubic
+centimeters of thiosulfate used subtracted from twenty-five will give
+the number of cubic centimeters of the copper solution which would be
+reduced by five cubic centimeters of the sugar solution used.</p>
+
+<p class="blockquot"><i>Example.</i>—In the proportions given above it
+was found that eleven cubic centimeters of thiosulfate were required
+to saturate the iodin set free. Then 25 - 11 = 14 cubic centimeters
+of copper solution reduced by five cubic centimeters of the sugar
+solution. Since one cubic centimeter of the copper solution is reduced
+by 0.0036 gram of dextrose the total dextrose in the five cubic
+centimeters = 0.0036 × 5 = 0.0180 gram.</p>
+
+<p>The above method does not seem to have any practical advantage over
+those based on noting the disappearance of the copper and is given only
+to illustrate the principle of the process. While the titration of the
+iodin by sodium thiosulfate is easily accomplished in the absence of
+organic matter, it becomes difficult, as shown by Ewell, when organic
+matters are present, as they always are in the oxidation of a sugar
+solution. Ewell has therefore proposed to determine the residual copper
+by a standard solution of potassium cyanid, but the method has not yet
+been developed.<a id="FNanchor_104" href="#Footnote_104" class="fnanchor">[104]</a></p>
+
+<h3>GRAVIMETRIC COPPER METHODS.</h3>
+
+<p><b>135. General Principles.</b>—In the preceding pages the principles
+of the volumetric methods of sugar analysis by means of alkaline copper
+<span class="pagenum"><a id="Page_150"></a>[Pg 150]</span>
+solution have been set forth. They depend either on the total
+decomposition of the copper solution employed by the reducing sugar,
+or else on the collection and titration of the cuprous oxid formed in
+the reaction. In the gravimetric methods the general principle of the
+process rests upon the collection of the cuprous oxid formed and its
+reduction to metallic copper, the weight of which serves as a starting
+point in the calculations of the weight of reducing sugar, which has
+been oxidized in the solution.</p>
+
+<p>The factors which affect the weight of copper obtained are essentially
+those which influence the results in the volumetric method. The
+composition of the copper solution, the temperature at which the
+reduction is accomplished, the time of heating, the strength of the
+sugar solution and the details of the manipulation, all affect more or
+less the quantity of copper obtained. As in the volumetric method also,
+the kind of reducing sugar must be taken in consideration, dextrose,
+levulose, invert sugar, maltose and other sugars having each a definite
+factor for reduction in given conditions. It follows, therefore, that
+only those results are of value which are obtained under definite
+conditions, rigidly controlled.</p>
+
+<p id="P_136"><b>136. Gravimetric Methods of the Department of Agriculture
+Laboratory.</b>—The process used in this laboratory is based
+essentially on the methods of Maercker, Behrend, Morgen, Meissl, Hiller
+and Allihn.<a id="FNanchor_105" href="#Footnote_105" class="fnanchor">[105]</a>
+Where dextrose alone is present, the table of factors proposed by
+Allihn is used and also the copper solution corresponding thereto.</p>
+
+<p class="spb1">For pure invert sugar, the tables and solutions of
+Meissl are used. For invert sugar in the presence of sucrose, the table
+and process proposed by Hiller are used.
+<span class="pagenum"><a id="Page_151"></a>[Pg 151]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_43" src="images/fig43.jpg" alt="" width="600" height="357" >
+    <p class="center spb1">Figure 43. Apparatus for the Electrolytic
+                 Deposition of Copper.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_152"></a>[Pg 152]</span>
+The reduction of the copper solution and the electrolytic deposition of
+the copper are accomplished as follows:</p>
+
+<p>The copper and alkali solutions are kept in separate bottles. After
+mixing the equivalent volume of the two solutions in a beaker, heat is
+applied and the mixture boiled. To the boiling liquid the proper volume
+of the cold sugar solution is added. This must always be less than the
+amount required for complete reduction. The solution is again brought
+into ebullition and kept boiling exactly two minutes. A two-minute
+sand glass is conveniently used to determine the time of boiling. At
+the end of this time an equal volume of freshly boiled cold water is
+added, and the supernatant liquor at once passed through a gooch under
+pressure. The residual cuprous oxid is covered with boiling water and
+washed by decantation until the wash water is no longer alkaline. It
+is more convenient to wash in such a way that, at the end, the greater
+part of the cuprous oxid is in the gooch. The felt and cuprous oxid are
+then returned to the beaker in which the reduction is made. The gooch
+is moistened with nitric acid to dissolve any adhering oxid and then
+is washed into the beaker. Enough nitric acid is added to bring all
+the oxid into solution, an excess being avoided, and a small amount
+of water added. The mixture is again passed under pressure through
+a gooch having a thin felt, to remove the asbestos and the filtrate
+collected in a flask of about 150 cubic centimeters capacity. The
+washing is continued until the gooch is free of copper, when the volume
+of the filtrate should be about 100 cubic centimeters. The liquid is
+transferred to a platinum dish holding about 175 cubic centimeters and
+the flask washed with about twenty-five cubic centimeters of water.
+From three to five cubic centimeters of strong sulfuric acid are added
+and the copper deposited by an electric current.</p>
+
+<p><b>137. Precipitating the Copper.</b>—When no more nitric acid is used
+than indicated in the previous paragraph, it will not be necessary
+to remove it by evaporation. The platinum dishes containing the
+solutions of the cuprous oxid are arranged as shown in the <a href="#FIG_43">figure</a>
+for the precipitation of the copper by the electric current. Each of the
+supporting stands has its base covered with sheet-copper, on which the
+platinum dishes rest. The uprights are made of heavy glass rods and
+carry the supports for the platinum cylinders which dip into the copper
+solutions. The current used is from the city service and is brought
+in through the lamp shown at the right of the <a href="#FIG_43">figure</a>.
+This current has a voltage of about 120. After passing the lamp it is conducted
+through the regulator shown at the right, a glass tube closed below by
+a stopper carrying a piece of platinum foil, and above by one holding
+a glass tube, in the lower end of which is sealed a piece of sheet
+<span class="pagenum"><a id="Page_153"></a>[Pg 153]</span>
+platinum connected, through the glass tube, with the lamp. The
+regulating tube contains dilute sulfuric acid. The strength of current
+desired is secured by adjusting the movable pole. A battery of this
+kind easily secures the precipitation of sixteen samples at once, but
+only twelve are shown in the <a href="#FIG_43">figure</a>. The practice here
+is to start the operation at the time of leaving the laboratory in the afternoon.
+The next morning the deposition of the copper will be found complete.
+The wiring of the apparatus is shown in the figure. The wire from the
+regulator is connected with the base of the first stand, and thence
+passes through the horizontal support to the base of the second, and so
+on. The return to the lamp is accomplished by means of the upper wire.
+This plan of arranging the apparatus has been used for two years, and
+with perfect satisfaction.</p>
+
+<p>Where a street current is not available, the following directions
+may be followed: Use four gravity cells, such as are employed in
+telegraphic work, for generating the current. This will be strong
+enough for one sample and by working longer for two. Connect the
+platinum dish with the zinc pole of the battery. The current is allowed
+to pass until all the copper is deposited. Where a larger number of
+samples is to be treated at once, the size of the battery must be
+correspondingly increased.</p>
+
+<p><b>138. Method Used at the Halle Station.</b>—The method used at the
+Halle station is the same as that originally described by Maercker
+for dextrose.<a id="FNanchor_106" href="#Footnote_106" class="fnanchor">[106]</a>
+The copper solution employed is the same as in the allihn method,
+<i>viz.</i>, 34.64 grams of copper sulfate in 500 cubic centimeters,
+and 173 grams of rochelle salt and 125 grams of potassium hydroxid in
+the same quantity of water. In a porcelain dish are placed thirty cubic
+centimeters of copper solution and an equal quantity of the alkali,
+sixty cubic centimeters of water added and the mixture boiled. To the
+solution, in lively ebullition, are added twenty-five cubic centimeters
+of the dextrose solution to be examined which must not contain more
+than one per cent of sugar. The mixture is again boiled and the
+separated cuprous oxid immediately poured into the filter and washed
+with hot water, until the disappearance of an alkaline reaction. For
+<span class="pagenum"><a id="Page_154"></a>[Pg 154]</span>
+filtering, a glass tube is employed, provided with a platinum disk,
+and resembling in every respect similar tubes used for the extraction
+of substances with ether and alcohol. The arrangement of the filtering
+apparatus is shown in <a href="#FIG_44">Fig. 44</a>. In the Halle method it is
+recommended that the tubes be prepared by introducing a platinum cone in place
+of the platinum disk and filling it with asbestos felt, pressing the felt
+tightly against the sides of the glass tube and making the asbestos
+fully one centimeter in thickness. This is a much less convenient
+<span class="pagenum"><a id="Page_155"></a>[Pg 155]</span>
+method of working than the one described above. After filtration and
+washing, the cuprous oxid is washed with ether and alcohol and dried
+for an hour at 110°, and finally reduced to metallic copper in a stream
+of pure dry hydrogen, heat being applied by means of a small flame. The
+apparatus for the reduction of the cuprous oxid is shown in <a href="#FIG_45">Fig. 45</a>.
+The metallic copper, after cooling and weighing, is dissolved in nitric
+acid, the tube washed with water, ether and alcohol, and again dried,
+when it is ready for use a second time. The percentage of dextrose is
+calculated from the milligrams of copper found by Allihn’s table.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_44" src="images/fig44.jpg" alt="" width="500" height="434" >
+    <p class="center">Figure 44. Apparatus for Filtering Copper Suboxid.</p>
+    <img id="FIG_45" src="images/fig45.jpg" alt="" width="500" height="438" >
+    <p class="center spb1">Figure 45. Apparatus for Reducing Copper Suboxid.</p>
+</div>
+
+<p><b>139. Tables for Use in the Gravimetric Determination of Reducing
+Sugars.</b>—The value of a table for computing the percentage of a
+reducing sugar present in a solution, is based on the accuracy with
+which the directions for the determination are followed. The solution
+must be of the proper strength and made in the way directed. The degree
+of dilution prescribed must be scrupulously preserved and the methods
+of boiling during reduction and washing the reduced copper, followed.
+The quantity of copper obtained by the use of different alkaline copper
+solutions and of sugar solutions of a strength different from that
+allowed by the fixed limits, is not a safe factor for computation.
+It must be understood, therefore, that in the use of the tables the
+directions which are given are to be followed in every particular.</p>
+
+<p id="P_140"><b>140. Allihn’s Gravimetric Method for the Determination of
+Dextrose.</b>—<i>Reagents</i>:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdr_top">I.</td>
+      <td class="tdl_top bb">&nbsp; 34.639 grams of CuSO₄.5H₂O,</td>
+      <td class="tdl_wsp bb">dissolved in water and diluted<br> to half a liter:</td>
+   </tr><tr>
+      <td class="tdr">II.</td>
+      <td class="tdl_wsp">173 grams of rochelle salts</td>
+      <td class="tdc">dissolved in water and diluted</td>
+   </tr><tr>
+      <td class="tdr">&nbsp;</td>
+      <td class="tdl_wsp">125 grams of KOH,</td>
+      <td class="tdl_wsp">to half a liter.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><i>Manipulation</i>: Place thirty cubic centimeters of the copper
+solution (I), thirty cubic centimeters of the alkaline tartrate
+solution (II), and sixty cubic centimeters of water in a beaker and
+heat to boiling. Add twenty-five cubic centimeters of the solution
+of the material to be examined, which must be so prepared as not to
+contain more than one per cent of dextrose, and boil for two minutes.
+<span class="pagenum"><a id="Page_156"></a>[Pg 156]</span>
+Filter immediately after adding an equal volume of recently boiled cold
+water and obtain the weight of copper by one of the gravimetric methods
+given. The corresponding weight of dextrose is found by the following table:</p>
+
+<p class="f120"><b><span class="smcap">Allihn’s Table for the<br>
+Determination of Dextrose.</span></b></p>
+
+<ul class="index fs_110">
+<li class="isub3"><b>(A)</b> = Milligrams of copper.</li>
+<li class="isub3"><b>(B)</b> = Milligrams of dextrose.</li>
+</ul>
+
+<table class="spb1">
+   <thead><tr class="fs_110">
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; (B) &nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; (B) &nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; (B) &nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; (B) &nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; (B) &nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">10</td> <td class="tdc">&#8199;6.1</td>
+      <td class="tdc">46</td> <td class="tdc">23.9</td>
+      <td class="tdc">&#8199;82</td> <td class="tdc">41.8</td>
+      <td class="tdc">118</td> <td class="tdc">60.1</td>
+      <td class="tdc">154</td> <td class="tdc">78.6</td>
+   </tr><tr>
+      <td class="tdc">11</td> <td class="tdc">&#8199;6.6</td>
+      <td class="tdc">47</td> <td class="tdc">24.4</td>
+      <td class="tdc">&#8199;83</td> <td class="tdc">42.3</td>
+      <td class="tdc">119</td> <td class="tdc">60.6</td>
+      <td class="tdc">155</td> <td class="tdc">79.1</td>
+   </tr><tr>
+      <td class="tdc">12</td> <td class="tdc">&#8199;7.1</td>
+      <td class="tdc">48</td> <td class="tdc">24.9</td>
+      <td class="tdc">&#8199;84</td> <td class="tdc">42.8</td>
+      <td class="tdc">120</td> <td class="tdc">61.1</td>
+      <td class="tdc">156</td> <td class="tdc">79.6</td>
+   </tr><tr>
+      <td class="tdc">13</td> <td class="tdc">&#8199;7.6</td>
+      <td class="tdc">49</td> <td class="tdc">25.4</td>
+      <td class="tdc">&#8199;85</td> <td class="tdc">43.4</td>
+      <td class="tdc">121</td> <td class="tdc">61.6</td>
+      <td class="tdc">157</td> <td class="tdc">80.1</td>
+   </tr><tr>
+      <td class="tdc">14</td> <td class="tdc">&#8199;8.1</td>
+      <td class="tdc">50</td> <td class="tdc">25.9</td>
+      <td class="tdc">&#8199;86</td> <td class="tdc">43.9</td>
+      <td class="tdc">122</td> <td class="tdc">62.1</td>
+      <td class="tdc">158</td> <td class="tdc">80.7</td>
+   </tr><tr>
+      <td class="tdc">15</td> <td class="tdc">&#8199;8.6</td>
+      <td class="tdc">51</td> <td class="tdc">26.4</td>
+      <td class="tdc">&#8199;87</td> <td class="tdc">44.4</td>
+      <td class="tdc">123</td> <td class="tdc">62.6</td>
+      <td class="tdc">159</td> <td class="tdc">81.2</td>
+   </tr><tr>
+      <td class="tdc">16</td> <td class="tdc">&#8199;9.0</td>
+      <td class="tdc">52</td> <td class="tdc">26.9</td>
+      <td class="tdc">&#8199;88</td> <td class="tdc">44.9</td>
+      <td class="tdc">124</td> <td class="tdc">63.1</td>
+      <td class="tdc">160</td> <td class="tdc">81.7</td>
+   </tr><tr>
+      <td class="tdc">17</td> <td class="tdc">&#8199;9.5</td>
+      <td class="tdc">53</td> <td class="tdc">27.4</td>
+      <td class="tdc">&#8199;89</td> <td class="tdc">45.4</td>
+      <td class="tdc">125</td> <td class="tdc">63.7</td>
+      <td class="tdc">161</td> <td class="tdc">82.2</td>
+   </tr><tr>
+      <td class="tdc">18</td> <td class="tdc">10.0</td>
+      <td class="tdc">54</td> <td class="tdc">27.9</td>
+      <td class="tdc">&#8199;90</td> <td class="tdc">45.9</td>
+      <td class="tdc">126</td> <td class="tdc">64.2</td>
+      <td class="tdc">162</td> <td class="tdc">82.7</td>
+   </tr><tr>
+      <td class="tdc bb">19</td> <td class="tdc bb">10.5</td>
+      <td class="tdc bb">55</td> <td class="tdc bb">28.4</td>
+      <td class="tdc bb">&#8199;91</td> <td class="tdc bb">46.4</td>
+      <td class="tdc bb">127</td> <td class="tdc bb">64.7</td>
+      <td class="tdc bb">163</td> <td class="tdc bb">83.3</td>
+   </tr><tr>
+      <td class="tdc">20</td> <td class="tdc">11.0</td>
+      <td class="tdc">56</td> <td class="tdc">28.8</td>
+      <td class="tdc">&#8199;92</td> <td class="tdc">46.9</td>
+      <td class="tdc">128</td> <td class="tdc">65.2</td>
+      <td class="tdc">164</td> <td class="tdc">83.8</td>
+   </tr><tr>
+      <td class="tdc">21</td> <td class="tdc">11.5</td>
+      <td class="tdc">57</td> <td class="tdc">29.3</td>
+      <td class="tdc">&#8199;93</td> <td class="tdc">47.4</td>
+      <td class="tdc">129</td> <td class="tdc">65.7</td>
+      <td class="tdc">165</td> <td class="tdc">84.3</td>
+   </tr><tr>
+      <td class="tdc">22</td> <td class="tdc">12.0</td>
+      <td class="tdc">58</td> <td class="tdc">29.8</td>
+      <td class="tdc">&#8199;94</td> <td class="tdc">47.9</td>
+      <td class="tdc">130</td> <td class="tdc">66.2</td>
+      <td class="tdc">166</td> <td class="tdc">84.8</td>
+   </tr><tr>
+      <td class="tdc">23</td> <td class="tdc">12.5</td>
+      <td class="tdc">59</td> <td class="tdc">30.3</td>
+      <td class="tdc">&#8199;95</td> <td class="tdc">48.4</td>
+      <td class="tdc">131</td> <td class="tdc">66.7</td>
+      <td class="tdc">167</td> <td class="tdc">85.3</td>
+   </tr><tr>
+      <td class="tdc">24</td> <td class="tdc">13.0</td>
+      <td class="tdc">60</td> <td class="tdc">30.8</td>
+      <td class="tdc">&#8199;96</td> <td class="tdc">48.9</td>
+      <td class="tdc">132</td> <td class="tdc">67.2</td>
+      <td class="tdc">168</td> <td class="tdc">85.9</td>
+   </tr><tr>
+      <td class="tdc">25</td> <td class="tdc">13.5</td>
+      <td class="tdc">61</td> <td class="tdc">31.3</td>
+      <td class="tdc">&#8199;97</td> <td class="tdc">49.4</td>
+      <td class="tdc">133</td> <td class="tdc">67.7</td>
+      <td class="tdc">169</td> <td class="tdc">86.4</td>
+   </tr><tr>
+      <td class="tdc">26</td> <td class="tdc">14.0</td>
+      <td class="tdc">62</td> <td class="tdc">31.8</td>
+      <td class="tdc">&#8199;98</td> <td class="tdc">49.9</td>
+      <td class="tdc">134</td> <td class="tdc">68.2</td>
+      <td class="tdc">170</td> <td class="tdc">86.9</td>
+   </tr><tr>
+      <td class="tdc">27</td> <td class="tdc">14.5</td>
+      <td class="tdc">63</td> <td class="tdc">32.3</td>
+      <td class="tdc">&#8199;99</td> <td class="tdc">50.4</td>
+      <td class="tdc">135</td> <td class="tdc">68.8</td>
+      <td class="tdc">171</td> <td class="tdc">87.4</td>
+   </tr><tr>
+      <td class="tdc">28</td> <td class="tdc">15.0</td>
+      <td class="tdc">64</td> <td class="tdc">32.8</td>
+      <td class="tdc">100</td> <td class="tdc">50.9</td>
+      <td class="tdc">136</td> <td class="tdc">69.3</td>
+      <td class="tdc">172</td> <td class="tdc">87.9</td>
+   </tr><tr>
+      <td class="tdc bb">29</td> <td class="tdc bb">15.5</td>
+      <td class="tdc bb">65</td> <td class="tdc bb">33.3</td>
+      <td class="tdc bb">101</td> <td class="tdc bb">51.4</td>
+      <td class="tdc bb">137</td> <td class="tdc bb">69.8</td>
+      <td class="tdc bb">173</td> <td class="tdc bb">88.5</td>
+   </tr><tr>
+      <td class="tdc">30</td> <td class="tdc">16.0</td>
+      <td class="tdc">66</td> <td class="tdc">33.8</td>
+      <td class="tdc">102</td> <td class="tdc">51.9</td>
+      <td class="tdc">138</td> <td class="tdc">70.3</td>
+      <td class="tdc">174</td> <td class="tdc">89.0</td>
+   </tr><tr>
+      <td class="tdc">31</td> <td class="tdc">16.5</td>
+      <td class="tdc">67</td> <td class="tdc">34.3</td>
+      <td class="tdc">103</td> <td class="tdc">52.4</td>
+      <td class="tdc">139</td> <td class="tdc">70.8</td>
+      <td class="tdc">175</td> <td class="tdc">89.5</td>
+   </tr><tr>
+      <td class="tdc">32</td> <td class="tdc">17.0</td>
+      <td class="tdc">68</td> <td class="tdc">34.8</td>
+      <td class="tdc">104</td> <td class="tdc">52.9</td>
+      <td class="tdc">140</td> <td class="tdc">71.3</td>
+      <td class="tdc">176</td> <td class="tdc">90.0</td>
+   </tr><tr>
+      <td class="tdc">33</td> <td class="tdc">17.5</td>
+      <td class="tdc">69</td> <td class="tdc">35.3</td>
+      <td class="tdc">105</td> <td class="tdc">53.5</td>
+      <td class="tdc">141</td> <td class="tdc">71.8</td>
+      <td class="tdc">177</td> <td class="tdc">90.5</td>
+   </tr><tr>
+      <td class="tdc">34</td> <td class="tdc">18.0</td>
+      <td class="tdc">70</td> <td class="tdc">35.8</td>
+      <td class="tdc">106</td> <td class="tdc">54.0</td>
+      <td class="tdc">142</td> <td class="tdc">72.3</td>
+      <td class="tdc">178</td> <td class="tdc">91.1</td>
+   </tr><tr>
+      <td class="tdc">35</td> <td class="tdc">18.5</td>
+      <td class="tdc">71</td> <td class="tdc">36.3</td>
+      <td class="tdc">107</td> <td class="tdc">54.5</td>
+      <td class="tdc">143</td> <td class="tdc">72.9</td>
+      <td class="tdc">179</td> <td class="tdc">91.6</td>
+   </tr><tr>
+      <td class="tdc">36</td> <td class="tdc">18.9</td>
+      <td class="tdc">72</td> <td class="tdc">36.8</td>
+      <td class="tdc">108</td> <td class="tdc">55.0</td>
+      <td class="tdc">144</td> <td class="tdc">73.4</td>
+      <td class="tdc">180</td> <td class="tdc">92.1</td>
+   </tr><tr>
+      <td class="tdc">37</td> <td class="tdc">19.4</td>
+      <td class="tdc">73</td> <td class="tdc">37.3</td>
+      <td class="tdc">109</td> <td class="tdc">55.5</td>
+      <td class="tdc">145</td> <td class="tdc">73.9</td>
+      <td class="tdc">181</td> <td class="tdc">92.6</td>
+   </tr><tr>
+      <td class="tdc">38</td> <td class="tdc">19.9</td>
+      <td class="tdc">74</td> <td class="tdc">37.8</td>
+      <td class="tdc">110</td> <td class="tdc">56.0</td>
+      <td class="tdc">146</td> <td class="tdc">74.4</td>
+      <td class="tdc">182</td> <td class="tdc">93.1</td>
+   </tr><tr>
+      <td class="tdc bb">39</td> <td class="tdc bb">20.4</td>
+      <td class="tdc bb">75</td> <td class="tdc bb">38.3</td>
+      <td class="tdc bb">111</td> <td class="tdc bb">56.5</td>
+      <td class="tdc bb">147</td> <td class="tdc bb">74.9</td>
+      <td class="tdc bb">183</td> <td class="tdc bb">93.7</td>
+   </tr><tr>
+      <td class="tdc">40</td> <td class="tdc">20.9</td>
+      <td class="tdc">76</td> <td class="tdc">38.8</td>
+      <td class="tdc">112</td> <td class="tdc">57.0</td>
+      <td class="tdc">148</td> <td class="tdc">75.5</td>
+      <td class="tdc">184</td> <td class="tdc">94.2</td>
+   </tr><tr>
+      <td class="tdc">41</td> <td class="tdc">21.4</td>
+      <td class="tdc">77</td> <td class="tdc">39.3</td>
+      <td class="tdc">113</td> <td class="tdc">57.5</td>
+      <td class="tdc">149</td> <td class="tdc">76.0</td>
+      <td class="tdc">185</td> <td class="tdc">94.7</td>
+   </tr><tr>
+      <td class="tdc">42</td> <td class="tdc">21.9</td>
+      <td class="tdc">78</td> <td class="tdc">39.8</td>
+      <td class="tdc">114</td> <td class="tdc">58.0</td>
+      <td class="tdc">150</td> <td class="tdc">76.5</td>
+      <td class="tdc">186</td> <td class="tdc">95.2</td>
+   </tr><tr>
+      <td class="tdc">43</td> <td class="tdc">22.4</td>
+      <td class="tdc">79</td> <td class="tdc">40.3</td>
+      <td class="tdc">115</td> <td class="tdc">58.6</td>
+      <td class="tdc">151</td> <td class="tdc">77.0</td>
+      <td class="tdc">187</td> <td class="tdc">95.7</td>
+   </tr><tr>
+      <td class="tdc">44</td> <td class="tdc">22.9</td>
+      <td class="tdc">80</td> <td class="tdc">40.8</td>
+      <td class="tdc">116</td> <td class="tdc">59.1</td>
+      <td class="tdc">152</td> <td class="tdc">77.5</td>
+      <td class="tdc">188</td> <td class="tdc">96.3</td>
+   </tr><tr>
+      <td class="tdc">45</td> <td class="tdc">23.4</td>
+      <td class="tdc">81</td> <td class="tdc">41.3</td>
+      <td class="tdc">117</td> <td class="tdc">59.6</td>
+      <td class="tdc">153</td> <td class="tdc">78.1</td>
+      <td class="tdc">189</td> <td class="tdc">96.8</td>
+   </tr><tr>
+      <td class="tdc" colspan="10">&nbsp;<span class="pagenum"><a id="Page_157"></a>[Pg 157]</span></td>
+   </tr><tr class="f110">
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+   </tr><tr>
+      <td class="tdc">190</td> <td class="tdc">&#8199;97.3</td>
+      <td class="tdc">233</td> <td class="tdc">120.1</td>
+      <td class="tdc">276</td> <td class="tdc">143.3</td>
+      <td class="tdc">319</td> <td class="tdc">167.0</td>
+      <td class="tdc">362</td> <td class="tdc">191.1</td>
+   </tr><tr>
+      <td class="tdc">191</td> <td class="tdc">&#8199;97.8</td>
+      <td class="tdc">234</td> <td class="tdc">120.7</td>
+      <td class="tdc">277</td> <td class="tdc">143.9</td>
+      <td class="tdc">320</td> <td class="tdc">167.5</td>
+      <td class="tdc">363</td> <td class="tdc">191.7</td>
+   </tr><tr>
+      <td class="tdc">192</td> <td class="tdc">&#8199;98.4</td>
+      <td class="tdc">235</td> <td class="tdc">121.2</td>
+      <td class="tdc">278</td> <td class="tdc">144.4</td>
+      <td class="tdc">321</td> <td class="tdc">168.1</td>
+      <td class="tdc">364</td> <td class="tdc">192.3</td>
+   </tr><tr>
+      <td class="tdc">193</td> <td class="tdc">&#8199;98.9</td>
+      <td class="tdc">236</td> <td class="tdc">121.7</td>
+      <td class="tdc">279</td> <td class="tdc">145.0</td>
+      <td class="tdc">322</td> <td class="tdc">168.6</td>
+      <td class="tdc">365</td> <td class="tdc">192.9</td>
+   </tr><tr>
+      <td class="tdc">194</td> <td class="tdc">&#8199;99.4</td>
+      <td class="tdc">237</td> <td class="tdc">122.3</td>
+      <td class="tdc">280</td> <td class="tdc">145.5</td>
+      <td class="tdc">323</td> <td class="tdc">169.2</td>
+      <td class="tdc">366</td> <td class="tdc">193.4</td>
+   </tr><tr>
+      <td class="tdc">195</td> <td class="tdc">100.0</td>
+      <td class="tdc">238</td> <td class="tdc">122.8</td>
+      <td class="tdc">281</td> <td class="tdc">146.1</td>
+      <td class="tdc">324</td> <td class="tdc">169.7</td>
+      <td class="tdc">367</td> <td class="tdc">194.0</td>
+   </tr><tr>
+      <td class="tdc">196</td> <td class="tdc">100.5</td>
+      <td class="tdc">239</td> <td class="tdc">123.4</td>
+      <td class="tdc">282</td> <td class="tdc">146.6</td>
+      <td class="tdc">325</td> <td class="tdc">170.3</td>
+      <td class="tdc">368</td> <td class="tdc">194.6</td>
+   </tr><tr>
+      <td class="tdc">197</td> <td class="tdc">101.0</td>
+      <td class="tdc">240</td> <td class="tdc">123.9</td>
+      <td class="tdc">283</td> <td class="tdc">147.2</td>
+      <td class="tdc">326</td> <td class="tdc">170.9</td>
+      <td class="tdc">369</td> <td class="tdc">195.1</td>
+   </tr><tr>
+      <td class="tdc">198</td> <td class="tdc">101.5</td>
+      <td class="tdc">241</td> <td class="tdc">124.4</td>
+      <td class="tdc">284</td> <td class="tdc">147.7</td>
+      <td class="tdc">327</td> <td class="tdc">171.4</td>
+      <td class="tdc">370</td> <td class="tdc">195.7</td>
+   </tr><tr>
+      <td class="tdc bb">199</td> <td class="tdc bb">102.0</td>
+      <td class="tdc bb">242</td> <td class="tdc bb">125.0</td>
+      <td class="tdc bb">285</td> <td class="tdc bb">148.3</td>
+      <td class="tdc bb">328</td> <td class="tdc bb">172.0</td>
+      <td class="tdc bb">371</td> <td class="tdc bb">196.3</td>
+   </tr><tr>
+      <td class="tdc">200</td> <td class="tdc">102.6</td>
+      <td class="tdc">243</td> <td class="tdc">125.5</td>
+      <td class="tdc">286</td> <td class="tdc">148.8</td>
+      <td class="tdc">329</td> <td class="tdc">172.5</td>
+      <td class="tdc">372</td> <td class="tdc">196.8</td>
+   </tr><tr>
+      <td class="tdc">201</td> <td class="tdc">103.1</td>
+      <td class="tdc">244</td> <td class="tdc">126.0</td>
+      <td class="tdc">287</td> <td class="tdc">149.5</td>
+      <td class="tdc">330</td> <td class="tdc">173.1</td>
+      <td class="tdc">373</td> <td class="tdc">197.4</td>
+   </tr><tr>
+      <td class="tdc">202</td> <td class="tdc">103.7</td>
+      <td class="tdc">245</td> <td class="tdc">126.6</td>
+      <td class="tdc">288</td> <td class="tdc">149.4</td>
+      <td class="tdc">331</td> <td class="tdc">173.7</td>
+      <td class="tdc">374</td> <td class="tdc">198.0</td>
+   </tr><tr>
+      <td class="tdc">203</td> <td class="tdc">104.2</td>
+      <td class="tdc">246</td> <td class="tdc">127.1</td>
+      <td class="tdc">289</td> <td class="tdc">150.9</td>
+      <td class="tdc">332</td> <td class="tdc">174.2</td>
+      <td class="tdc">375</td> <td class="tdc">198.6</td>
+   </tr><tr>
+      <td class="tdc">204</td> <td class="tdc">104.7</td>
+      <td class="tdc">247</td> <td class="tdc">127.6</td>
+      <td class="tdc">290</td> <td class="tdc">151.0</td>
+      <td class="tdc">333</td> <td class="tdc">174.8</td>
+      <td class="tdc">376</td> <td class="tdc">199.1</td>
+   </tr><tr>
+      <td class="tdc">205</td> <td class="tdc">105.3</td>
+      <td class="tdc">248</td> <td class="tdc">128.1</td>
+      <td class="tdc">291</td> <td class="tdc">151.6</td>
+      <td class="tdc">334</td> <td class="tdc">175.3</td>
+      <td class="tdc">377</td> <td class="tdc">199.7</td>
+   </tr><tr>
+      <td class="tdc">206</td> <td class="tdc">105.8</td>
+      <td class="tdc">249</td> <td class="tdc">128.7</td>
+      <td class="tdc">292</td> <td class="tdc">152.1</td>
+      <td class="tdc">335</td> <td class="tdc">175.9</td>
+      <td class="tdc">378</td> <td class="tdc">200.3</td>
+   </tr><tr>
+      <td class="tdc">207</td> <td class="tdc">106.3</td>
+      <td class="tdc">250</td> <td class="tdc">129.2</td>
+      <td class="tdc">293</td> <td class="tdc">152.7</td>
+      <td class="tdc">336</td> <td class="tdc">176.5</td>
+      <td class="tdc">379</td> <td class="tdc">200.8</td>
+   </tr><tr>
+      <td class="tdc">208</td> <td class="tdc">106.8</td>
+      <td class="tdc">251</td> <td class="tdc">129.7</td>
+      <td class="tdc">294</td> <td class="tdc">153.2</td>
+      <td class="tdc">337</td> <td class="tdc">177.0</td>
+      <td class="tdc">380</td> <td class="tdc">201.4</td>
+   </tr><tr>
+      <td class="tdc">209</td> <td class="tdc">107.4</td>
+      <td class="tdc">252</td> <td class="tdc">130.3</td>
+      <td class="tdc">295</td> <td class="tdc">153.8</td>
+      <td class="tdc">338</td> <td class="tdc">177.6</td>
+      <td class="tdc">381</td> <td class="tdc">202.0</td>
+   </tr><tr>
+      <td class="tdc">210</td> <td class="tdc">107.9</td>
+      <td class="tdc">253</td> <td class="tdc">130.8</td>
+      <td class="tdc">296</td> <td class="tdc">154.3</td>
+      <td class="tdc">339</td> <td class="tdc">178.1</td>
+      <td class="tdc">382</td> <td class="tdc">202.5</td>
+   </tr><tr>
+      <td class="tdc">211</td> <td class="tdc">108.4</td>
+      <td class="tdc">254</td> <td class="tdc">131.4</td>
+      <td class="tdc">297</td> <td class="tdc">154.9</td>
+      <td class="tdc">340</td> <td class="tdc">178.7</td>
+      <td class="tdc">383</td> <td class="tdc">203.1</td>
+   </tr><tr>
+      <td class="tdc">212</td> <td class="tdc">109.0</td>
+      <td class="tdc">255</td> <td class="tdc">131.9</td>
+      <td class="tdc">298</td> <td class="tdc">155.4</td>
+      <td class="tdc">341</td> <td class="tdc">179.3</td>
+      <td class="tdc">384</td> <td class="tdc">203.7</td>
+   </tr><tr>
+      <td class="tdc">213</td> <td class="tdc">109.5</td>
+      <td class="tdc">256</td> <td class="tdc">132.4</td>
+      <td class="tdc">299</td> <td class="tdc">156.0</td>
+      <td class="tdc">342</td> <td class="tdc">179.8</td>
+      <td class="tdc">385</td> <td class="tdc">204.3</td>
+   </tr><tr>
+      <td class="tdc">214</td> <td class="tdc">110.0</td>
+      <td class="tdc">257</td> <td class="tdc">133.0</td>
+      <td class="tdc">300</td> <td class="tdc">156.5</td>
+      <td class="tdc">343</td> <td class="tdc">180.4</td>
+      <td class="tdc">386</td> <td class="tdc">204.8</td>
+   </tr><tr>
+      <td class="tdc">215</td> <td class="tdc">110.6</td>
+      <td class="tdc">258</td> <td class="tdc">133.5</td>
+      <td class="tdc">301</td> <td class="tdc">157.1</td>
+      <td class="tdc">344</td> <td class="tdc">180.9</td>
+      <td class="tdc">387</td> <td class="tdc">205.4</td>
+   </tr><tr>
+      <td class="tdc">216</td> <td class="tdc">111.1</td>
+      <td class="tdc">259</td> <td class="tdc">134.1</td>
+      <td class="tdc">302</td> <td class="tdc">157.6</td>
+      <td class="tdc">345</td> <td class="tdc">181.5</td>
+      <td class="tdc">388</td> <td class="tdc">206.0</td>
+   </tr><tr>
+      <td class="tdc">217</td> <td class="tdc">111.6</td>
+      <td class="tdc">260</td> <td class="tdc">134.6</td>
+      <td class="tdc">303</td> <td class="tdc">158.2</td>
+      <td class="tdc">346</td> <td class="tdc">182.1</td>
+      <td class="tdc">389</td> <td class="tdc">206.5</td>
+   </tr><tr>
+      <td class="tdc">218</td> <td class="tdc">112.1</td>
+      <td class="tdc">261</td> <td class="tdc">135.1</td>
+      <td class="tdc">304</td> <td class="tdc">158.7</td>
+      <td class="tdc">347</td> <td class="tdc">182.6</td>
+      <td class="tdc">390</td> <td class="tdc">207.1</td>
+   </tr><tr>
+      <td class="tdc bb">219</td> <td class="tdc bb">112.7</td>
+      <td class="tdc bb">262</td> <td class="tdc bb">135.7</td>
+      <td class="tdc bb">305</td> <td class="tdc bb">159.3</td>
+      <td class="tdc bb">348</td> <td class="tdc bb">183.2</td>
+      <td class="tdc bb">391</td> <td class="tdc bb">207.7</td>
+   </tr><tr>
+      <td class="tdc">220</td> <td class="tdc">113.2</td>
+      <td class="tdc">263</td> <td class="tdc">136.2</td>
+      <td class="tdc">306</td> <td class="tdc">159.8</td>
+      <td class="tdc">349</td> <td class="tdc">183.7</td>
+      <td class="tdc">392</td> <td class="tdc">208.3</td>
+   </tr><tr>
+      <td class="tdc">221</td> <td class="tdc">113.7</td>
+      <td class="tdc">264</td> <td class="tdc">136.8</td>
+      <td class="tdc">307</td> <td class="tdc">160.4</td>
+      <td class="tdc">350</td> <td class="tdc">184.3</td>
+      <td class="tdc">393</td> <td class="tdc">208.8</td>
+   </tr><tr>
+      <td class="tdc">222</td> <td class="tdc">114.3</td>
+      <td class="tdc">265</td> <td class="tdc">137.3</td>
+      <td class="tdc">308</td> <td class="tdc">160.9</td>
+      <td class="tdc">351</td> <td class="tdc">184.9</td>
+      <td class="tdc">394</td> <td class="tdc">209.4</td>
+   </tr><tr>
+      <td class="tdc">223</td> <td class="tdc">114.8</td>
+      <td class="tdc">266</td> <td class="tdc">137.8</td>
+      <td class="tdc">309</td> <td class="tdc">161.5</td>
+      <td class="tdc">352</td> <td class="tdc">185.4</td>
+      <td class="tdc">395</td> <td class="tdc">210.0</td>
+   </tr><tr>
+      <td class="tdc">224</td> <td class="tdc">115.3</td>
+      <td class="tdc">267</td> <td class="tdc">138.4</td>
+      <td class="tdc">310</td> <td class="tdc">162.0</td>
+      <td class="tdc">353</td> <td class="tdc">186.0</td>
+      <td class="tdc">396</td> <td class="tdc">210.6</td>
+   </tr><tr>
+      <td class="tdc">225</td> <td class="tdc">115.9</td>
+      <td class="tdc">268</td> <td class="tdc">138.9</td>
+      <td class="tdc">311</td> <td class="tdc">162.6</td>
+      <td class="tdc">354</td> <td class="tdc">186.6</td>
+      <td class="tdc">397</td> <td class="tdc">211.2</td>
+   </tr><tr>
+      <td class="tdc">226</td> <td class="tdc">116.4</td>
+      <td class="tdc">269</td> <td class="tdc">139.5</td>
+      <td class="tdc">312</td> <td class="tdc">163.1</td>
+      <td class="tdc">355</td> <td class="tdc">187.2</td>
+      <td class="tdc">398</td> <td class="tdc">211.7</td>
+   </tr><tr>
+      <td class="tdc">227</td> <td class="tdc">116.9</td>
+      <td class="tdc">270</td> <td class="tdc">140.0</td>
+      <td class="tdc">313</td> <td class="tdc">163.7</td>
+      <td class="tdc">356</td> <td class="tdc">187.7</td>
+      <td class="tdc">399</td> <td class="tdc">212.3</td>
+   </tr><tr>
+      <td class="tdc">228</td> <td class="tdc">117.4</td>
+      <td class="tdc">271</td> <td class="tdc">140.6</td>
+      <td class="tdc">314</td> <td class="tdc">164.2</td>
+      <td class="tdc">357</td> <td class="tdc">188.3</td>
+      <td class="tdc">400</td> <td class="tdc">212.9</td>
+   </tr><tr>
+      <td class="tdc">229</td> <td class="tdc">118.0</td>
+      <td class="tdc">272</td> <td class="tdc">141.1</td>
+      <td class="tdc">315</td> <td class="tdc">164.8</td>
+      <td class="tdc">358</td> <td class="tdc">188.9</td>
+      <td class="tdc">401</td> <td class="tdc">213.5</td>
+   </tr><tr>
+      <td class="tdc">230</td> <td class="tdc">118.5</td>
+      <td class="tdc">273</td> <td class="tdc">141.7</td>
+      <td class="tdc">316</td> <td class="tdc">165.3</td>
+      <td class="tdc">359</td> <td class="tdc">189.4</td>
+      <td class="tdc">402</td> <td class="tdc">214.1</td>
+   </tr><tr>
+      <td class="tdc">231</td> <td class="tdc">119.0</td>
+      <td class="tdc">274</td> <td class="tdc">142.2</td>
+      <td class="tdc">317</td> <td class="tdc">165.9</td>
+      <td class="tdc">360</td> <td class="tdc">190.0</td>
+      <td class="tdc">403</td> <td class="tdc">214.6</td>
+   </tr><tr>
+      <td class="tdc">232</td> <td class="tdc">119.6</td>
+      <td class="tdc">275</td> <td class="tdc">142.8</td>
+      <td class="tdc">318</td> <td class="tdc">166.4</td>
+      <td class="tdc">361</td> <td class="tdc">190.6</td>
+      <td class="tdc">404</td> <td class="tdc">215.2</td>
+   </tr><tr>
+      <td class="tdc" colspan="10">&nbsp;<span class="pagenum"><a id="Page_158"></a>[Pg 158]</span></td>
+   </tr><tr class="f110">
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+   </tr><tr>
+      <td class="tdc">405</td> <td class="tdc">215.8</td>
+      <td class="tdc">417</td> <td class="tdc">222.8</td>
+      <td class="tdc">429</td> <td class="tdc">229.8</td>
+      <td class="tdc">441</td> <td class="tdc">236.9</td>
+      <td class="tdc">453</td> <td class="tdc">244.0</td>
+   </tr><tr>
+      <td class="tdc">406</td> <td class="tdc">216.4</td>
+      <td class="tdc">418</td> <td class="tdc">223.3</td>
+      <td class="tdc">430</td> <td class="tdc">230.4</td>
+      <td class="tdc">442</td> <td class="tdc">237.5</td>
+      <td class="tdc">454</td> <td class="tdc">244.6</td>
+   </tr><tr>
+      <td class="tdc">407</td> <td class="tdc">217.0</td>
+      <td class="tdc">419</td> <td class="tdc">223.9</td>
+      <td class="tdc">431</td> <td class="tdc">231.0</td>
+      <td class="tdc">443</td> <td class="tdc">238.1</td>
+      <td class="tdc">455</td> <td class="tdc">245.2</td>
+   </tr><tr>
+      <td class="tdc">408</td> <td class="tdc">217.5</td>
+      <td class="tdc">420</td> <td class="tdc">224.5</td>
+      <td class="tdc">432</td> <td class="tdc">231.6</td>
+      <td class="tdc">444</td> <td class="tdc">238.7</td>
+      <td class="tdc">456</td> <td class="tdc">245.7</td>
+   </tr><tr>
+      <td class="tdc">409</td> <td class="tdc">218.1</td>
+      <td class="tdc">421</td> <td class="tdc">225.1</td>
+      <td class="tdc">433</td> <td class="tdc">232.2</td>
+      <td class="tdc">445</td> <td class="tdc">239.3</td>
+      <td class="tdc">457</td> <td class="tdc">246.3</td>
+   </tr><tr>
+      <td class="tdc">410</td> <td class="tdc">218.7</td>
+      <td class="tdc">422</td> <td class="tdc">225.7</td>
+      <td class="tdc">434</td> <td class="tdc">232.8</td>
+      <td class="tdc">446</td> <td class="tdc">239.8</td>
+      <td class="tdc">458</td> <td class="tdc">246.9</td>
+   </tr><tr>
+      <td class="tdc">411</td> <td class="tdc">219.3</td>
+      <td class="tdc">423</td> <td class="tdc">226.3</td>
+      <td class="tdc">435</td> <td class="tdc">233.4</td>
+      <td class="tdc">447</td> <td class="tdc">240.4</td>
+      <td class="tdc">459</td> <td class="tdc">247.5</td>
+   </tr><tr>
+      <td class="tdc">412</td> <td class="tdc">219.9</td>
+      <td class="tdc">424</td> <td class="tdc">226.9</td>
+      <td class="tdc">436</td> <td class="tdc">233.9</td>
+      <td class="tdc">448</td> <td class="tdc">241.0</td>
+      <td class="tdc">460</td> <td class="tdc">248.1</td>
+   </tr><tr>
+      <td class="tdc">413</td> <td class="tdc">220.4</td>
+      <td class="tdc">425</td> <td class="tdc">227.5</td>
+      <td class="tdc">437</td> <td class="tdc">234.5</td>
+      <td class="tdc">449</td> <td class="tdc">241.6</td>
+      <td class="tdc">461</td> <td class="tdc">248.7</td>
+   </tr><tr>
+      <td class="tdc">414</td> <td class="tdc">221.0</td>
+      <td class="tdc">426</td> <td class="tdc">228.0</td>
+      <td class="tdc">438</td> <td class="tdc">235.1</td>
+      <td class="tdc">450</td> <td class="tdc">242.2</td>
+      <td class="tdc">462</td> <td class="tdc">249.3</td>
+   </tr><tr>
+      <td class="tdc">415</td> <td class="tdc">221.6</td>
+      <td class="tdc">427</td> <td class="tdc">228.6</td>
+      <td class="tdc">439</td> <td class="tdc">235.7</td>
+      <td class="tdc">451</td> <td class="tdc">242.8</td>
+      <td class="tdc">463</td> <td class="tdc">249.9</td>
+   </tr><tr>
+      <td class="tdc">416</td> <td class="tdc">222.2</td>
+      <td class="tdc">428</td> <td class="tdc">229.2</td>
+      <td class="tdc">440</td> <td class="tdc">236.3</td>
+      <td class="tdc">452</td> <td class="tdc">243.4</td>
+      <td class="tdc">&nbsp;</td> <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p id="P_141"><b>141. Meissl’s Table for Invert Sugar.</b>—Invert sugar is usually
+the product of the hydrolysis of sucrose. The following table is to
+be used when the hydrolysis is complete, <i>i</i>. <i>e</i>., when no
+sucrose is left in the solution. The solution of copper sulfate and of
+the alkaline tartrate are made up as follows: 34.64 grams of copper
+sulfate in half a liter, and 173 grams of rochelle salt and 51.6 grams
+sodium hydroxid in the same volume. The quantity of sugar solution
+used must not contain more than 245 nor less than ninety milligrams of
+invert sugar.</p>
+
+<p>In the determination twenty-five cubic centimeters of the copper
+solution and an equal volume of the alkaline tartrate are mixed and
+boiled, the proper amount of sugar solution added to secure a quantity
+of invertose within the limits named, the volume completed to 100
+cubic centimeters with boiling water, and the mixture kept in lively
+ebullition for two minutes. An equal volume of recently boiled cold
+water is added and the cuprous oxid at once separated by filtration on
+asbestos under pressure, and washed free of alkali with boiling water.
+The metallic copper is secured by one of the methods already described.
+<span class="pagenum"><a id="Page_159"></a>[Pg 159]</span></p>
+
+<p class="f120"><b><span class="smcap">Table for Invert Sugar by Meissl and
+ Wien.</span></b><a id="FNanchor_107" href="#Footnote_107" class="fnanchor">[107]</a></p>
+
+<ul class="index fs_110">
+<li class="isub3"><b>(A)</b> = Milligrams of copper.</li>
+<li class="isub3"><b>(B)</b> = Milligrams of invert sugar.</li>
+</ul>
+
+<table class="spb1">
+   <thead><tr class="fs_110">
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; (B) &nbsp;&nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; (B) &nbsp;&nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; (B) &nbsp;&nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; (B) &nbsp;&nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">&#8199;90</td> <td class="tdc">46.9</td>
+      <td class="tdc">133</td> <td class="tdc">69.7</td>
+      <td class="tdc">176</td> <td class="tdc">&#8199;93.0</td>
+      <td class="tdc">219</td> <td class="tdc">117.0</td>
+   </tr><tr>
+      <td class="tdc">&#8199;91</td> <td class="tdc">47.4</td>
+      <td class="tdc">134</td> <td class="tdc">70.3</td>
+      <td class="tdc">177</td> <td class="tdc">&#8199;93.5</td>
+      <td class="tdc">220</td> <td class="tdc">117.5</td>
+   </tr><tr>
+      <td class="tdc">&#8199;92</td> <td class="tdc">47.9</td>
+      <td class="tdc">135</td> <td class="tdc">70.8</td>
+      <td class="tdc">178</td> <td class="tdc">&#8199;94.1</td>
+      <td class="tdc">221</td> <td class="tdc">118.1</td>
+   </tr><tr>
+      <td class="tdc">&#8199;93</td> <td class="tdc">48.4</td>
+      <td class="tdc">136</td> <td class="tdc">71.3</td>
+      <td class="tdc">179</td> <td class="tdc">&#8199;94.6</td>
+      <td class="tdc">222</td> <td class="tdc">118.7</td>
+   </tr><tr>
+      <td class="tdc">&#8199;94</td> <td class="tdc">48.9</td>
+      <td class="tdc">137</td> <td class="tdc">71.9</td>
+      <td class="tdc">180</td> <td class="tdc">&#8199;95.2</td>
+      <td class="tdc">223</td> <td class="tdc">119.2</td>
+   </tr><tr>
+      <td class="tdc">&#8199;95</td> <td class="tdc">49.5</td>
+      <td class="tdc">138</td> <td class="tdc">72.4</td>
+      <td class="tdc">181</td> <td class="tdc">&#8199;95.7</td>
+      <td class="tdc">224</td> <td class="tdc">119.8</td>
+   </tr><tr>
+      <td class="tdc">&#8199;96</td> <td class="tdc">50.0</td>
+      <td class="tdc">139</td> <td class="tdc">72.9</td>
+      <td class="tdc">182</td> <td class="tdc">&#8199;96.2</td>
+      <td class="tdc">225</td> <td class="tdc">120.4</td>
+   </tr><tr>
+      <td class="tdc">&#8199;97</td> <td class="tdc">50.5</td>
+      <td class="tdc">140</td> <td class="tdc">73.5</td>
+      <td class="tdc">183</td> <td class="tdc">&#8199;96.8</td>
+      <td class="tdc">226</td> <td class="tdc">120.9</td>
+   </tr><tr>
+      <td class="tdc">&#8199;98</td> <td class="tdc">51.1</td>
+      <td class="tdc">141</td> <td class="tdc">74.0</td>
+      <td class="tdc">184</td> <td class="tdc">&#8199;97.3</td>
+      <td class="tdc">227</td> <td class="tdc">121.5</td>
+   </tr><tr>
+      <td class="tdc">&#8199;99</td> <td class="tdc">51.6</td>
+      <td class="tdc">142</td> <td class="tdc">74.5</td>
+      <td class="tdc">185</td> <td class="tdc">&#8199;97.8</td>
+      <td class="tdc">228</td> <td class="tdc">122.1</td>
+   </tr><tr>
+      <td class="tdc">100</td> <td class="tdc">52.1</td>
+      <td class="tdc">143</td> <td class="tdc">75.1</td>
+      <td class="tdc">186</td> <td class="tdc">&#8199;98.4</td>
+      <td class="tdc">229</td> <td class="tdc">122.6</td>
+   </tr><tr>
+      <td class="tdc">101</td> <td class="tdc">52.7</td>
+      <td class="tdc">144</td> <td class="tdc">75.6</td>
+      <td class="tdc">187</td> <td class="tdc">&#8199;99.0</td>
+      <td class="tdc">230</td> <td class="tdc">123.2</td>
+   </tr><tr>
+      <td class="tdc">102</td> <td class="tdc">53.2</td>
+      <td class="tdc">145</td> <td class="tdc">76.1</td>
+      <td class="tdc">188</td> <td class="tdc">&#8199;99.5</td>
+      <td class="tdc">231</td> <td class="tdc">123.8</td>
+   </tr><tr>
+      <td class="tdc">103</td> <td class="tdc">53.7</td>
+      <td class="tdc">146</td> <td class="tdc">76.7</td>
+      <td class="tdc">189</td> <td class="tdc">100.1</td>
+      <td class="tdc">232</td> <td class="tdc">124.3</td>
+   </tr><tr>
+      <td class="tdc">104</td> <td class="tdc">54.3</td>
+      <td class="tdc">147</td> <td class="tdc">77.2</td>
+      <td class="tdc">190</td> <td class="tdc">100.6</td>
+      <td class="tdc">233</td> <td class="tdc">124.9</td>
+   </tr><tr>
+      <td class="tdc">105</td> <td class="tdc">54.8</td>
+      <td class="tdc">148</td> <td class="tdc">77.8</td>
+      <td class="tdc">191</td> <td class="tdc">101.2</td>
+      <td class="tdc">234</td> <td class="tdc">125.5</td>
+   </tr><tr>
+      <td class="tdc">106</td> <td class="tdc">55.3</td>
+      <td class="tdc">149</td> <td class="tdc">78.3</td>
+      <td class="tdc">192</td> <td class="tdc">101.7</td>
+      <td class="tdc">235</td> <td class="tdc">126.0</td>
+   </tr><tr>
+      <td class="tdc">107</td> <td class="tdc">55.9</td>
+      <td class="tdc">150</td> <td class="tdc">78.9</td>
+      <td class="tdc">193</td> <td class="tdc">102.3</td>
+      <td class="tdc">236</td> <td class="tdc">126.6</td>
+   </tr><tr>
+      <td class="tdc">108</td> <td class="tdc">56.4</td>
+      <td class="tdc">151</td> <td class="tdc">79.4</td>
+      <td class="tdc">194</td> <td class="tdc">102.9</td>
+      <td class="tdc">237</td> <td class="tdc">127.2</td>
+   </tr><tr class="bb">
+      <td class="tdc">109</td> <td class="tdc">56.9</td>
+      <td class="tdc">152</td> <td class="tdc">80.0</td>
+      <td class="tdc">195</td> <td class="tdc">103.4</td>
+      <td class="tdc">238</td> <td class="tdc">127.8</td>
+   </tr><tr>
+      <td class="tdc">110</td> <td class="tdc">57.5</td>
+      <td class="tdc">153</td> <td class="tdc">80.5</td>
+      <td class="tdc">196</td> <td class="tdc">104.0</td>
+      <td class="tdc">239</td> <td class="tdc">128.3</td>
+   </tr><tr>
+      <td class="tdc">111</td> <td class="tdc">58.0</td>
+      <td class="tdc">154</td> <td class="tdc">81.0</td>
+      <td class="tdc">197</td> <td class="tdc">104.6</td>
+      <td class="tdc">240</td> <td class="tdc">128.9</td>
+   </tr><tr>
+      <td class="tdc">112</td> <td class="tdc">58.5</td>
+      <td class="tdc">155</td> <td class="tdc">81.6</td>
+      <td class="tdc">198</td> <td class="tdc">105.1</td>
+      <td class="tdc">241</td> <td class="tdc">129.5</td>
+   </tr><tr>
+      <td class="tdc">113</td> <td class="tdc">59.1</td>
+      <td class="tdc">156</td> <td class="tdc">82.1</td>
+      <td class="tdc">199</td> <td class="tdc">105.7</td>
+      <td class="tdc">242</td> <td class="tdc">130.0</td>
+   </tr><tr>
+      <td class="tdc">114</td> <td class="tdc">59.6</td>
+      <td class="tdc">157</td> <td class="tdc">82.7</td>
+      <td class="tdc">200</td> <td class="tdc">106.3</td>
+      <td class="tdc">243</td> <td class="tdc">130.6</td>
+   </tr><tr>
+      <td class="tdc">115</td> <td class="tdc">60.1</td>
+      <td class="tdc">158</td> <td class="tdc">83.2</td>
+      <td class="tdc">201</td> <td class="tdc">106.8</td>
+      <td class="tdc">244</td> <td class="tdc">131.2</td>
+   </tr><tr>
+      <td class="tdc">116</td> <td class="tdc">60.7</td>
+      <td class="tdc">159</td> <td class="tdc">83.8</td>
+      <td class="tdc">202</td> <td class="tdc">107.4</td>
+      <td class="tdc">245</td> <td class="tdc">131.8</td>
+   </tr><tr>
+      <td class="tdc">117</td> <td class="tdc">61.2</td>
+      <td class="tdc">160</td> <td class="tdc">84.3</td>
+      <td class="tdc">203</td> <td class="tdc">107.9</td>
+      <td class="tdc">246</td> <td class="tdc">132.3</td>
+   </tr><tr>
+      <td class="tdc">118</td> <td class="tdc">61.7</td>
+      <td class="tdc">161</td> <td class="tdc">84.8</td>
+      <td class="tdc">204</td> <td class="tdc">108.5</td>
+      <td class="tdc">247</td> <td class="tdc">132.9</td>
+   </tr><tr>
+      <td class="tdc">119</td> <td class="tdc">62.3</td>
+      <td class="tdc">162</td> <td class="tdc">85.4</td>
+      <td class="tdc">205</td> <td class="tdc">109.1</td>
+      <td class="tdc">248</td> <td class="tdc">133.5</td>
+   </tr><tr>
+      <td class="tdc">120</td> <td class="tdc">62.8</td>
+      <td class="tdc">163</td> <td class="tdc">85.9</td>
+      <td class="tdc">206</td> <td class="tdc">109.6</td>
+      <td class="tdc">249</td> <td class="tdc">134.1</td>
+   </tr><tr>
+      <td class="tdc">121</td> <td class="tdc">63.3</td>
+      <td class="tdc">164</td> <td class="tdc">86.5</td>
+      <td class="tdc">207</td> <td class="tdc">110.2</td>
+      <td class="tdc">250</td> <td class="tdc">134.6</td>
+   </tr><tr>
+      <td class="tdc">122</td> <td class="tdc">63.9</td>
+      <td class="tdc">165</td> <td class="tdc">87.0</td>
+      <td class="tdc">208</td> <td class="tdc">110.8</td>
+      <td class="tdc">251</td> <td class="tdc">135.2</td>
+   </tr><tr>
+      <td class="tdc">123</td> <td class="tdc">64.4</td>
+      <td class="tdc">166</td> <td class="tdc">87.6</td>
+      <td class="tdc">209</td> <td class="tdc">111.3</td>
+      <td class="tdc">252</td> <td class="tdc">135.8</td>
+   </tr><tr>
+      <td class="tdc">124</td> <td class="tdc">64.9</td>
+      <td class="tdc">167</td> <td class="tdc">88.1</td>
+      <td class="tdc">210</td> <td class="tdc">111.9</td>
+      <td class="tdc">253</td> <td class="tdc">136.3</td>
+   </tr><tr>
+      <td class="tdc">125</td> <td class="tdc">65.5</td>
+      <td class="tdc">168</td> <td class="tdc">88.6</td>
+      <td class="tdc">211</td> <td class="tdc">112.5</td>
+      <td class="tdc">254</td> <td class="tdc">136.9</td>
+   </tr><tr>
+      <td class="tdc">126</td> <td class="tdc">66.0</td>
+      <td class="tdc">169</td> <td class="tdc">89.2</td>
+      <td class="tdc">212</td> <td class="tdc">113.0</td>
+      <td class="tdc">255</td> <td class="tdc">137.5</td>
+   </tr><tr>
+      <td class="tdc">127</td> <td class="tdc">66.5</td>
+      <td class="tdc">170</td> <td class="tdc">89.7</td>
+      <td class="tdc">213</td> <td class="tdc">113.6</td>
+      <td class="tdc">256</td> <td class="tdc">138.1</td>
+   </tr><tr>
+      <td class="tdc">128</td> <td class="tdc">67.1</td>
+      <td class="tdc">171</td> <td class="tdc">90.3</td>
+      <td class="tdc">214</td> <td class="tdc">114.2</td>
+      <td class="tdc">257</td> <td class="tdc">138.6</td>
+   </tr><tr>
+      <td class="tdc">129</td> <td class="tdc">67.6</td>
+      <td class="tdc">172</td> <td class="tdc">90.8</td>
+      <td class="tdc">215</td> <td class="tdc">114.7</td>
+      <td class="tdc">258</td> <td class="tdc">139.2</td>
+   </tr><tr>
+      <td class="tdc">130</td> <td class="tdc">68.1</td>
+      <td class="tdc">173</td> <td class="tdc">91.4</td>
+      <td class="tdc">216</td> <td class="tdc">115.3</td>
+      <td class="tdc">259</td> <td class="tdc">139.8</td>
+   </tr><tr>
+      <td class="tdc">131</td> <td class="tdc">68.7</td>
+      <td class="tdc">174</td> <td class="tdc">91.9</td>
+      <td class="tdc">217</td> <td class="tdc">115.8</td>
+      <td class="tdc">260</td> <td class="tdc">140.4</td>
+   </tr><tr>
+      <td class="tdc">132</td> <td class="tdc">69.2</td>
+      <td class="tdc">175</td> <td class="tdc">92.4</td>
+      <td class="tdc">218</td> <td class="tdc">116.4</td>
+      <td class="tdc">261</td> <td class="tdc">140.9</td>
+   </tr><tr>
+      <td class="tdc" colspan="8">&nbsp;<span class="pagenum"><a id="Page_160"></a>[Pg 160]</span></td>
+   </tr><tr class="f110">
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+   </tr><tr>
+      <td class="tdc">262</td> <td class="tdc">141.5</td>
+      <td class="tdc">305</td> <td class="tdc">166.8</td>
+      <td class="tdc">348</td> <td class="tdc">192.6</td>
+      <td class="tdc">391</td> <td class="tdc">219.3</td>
+   </tr><tr>
+      <td class="tdc">263</td> <td class="tdc">142.1</td>
+      <td class="tdc">306</td> <td class="tdc">167.3</td>
+      <td class="tdc">349</td> <td class="tdc">193.2</td>
+      <td class="tdc">392</td> <td class="tdc">219.9</td>
+   </tr><tr>
+      <td class="tdc">264</td> <td class="tdc">142.7</td>
+      <td class="tdc">307</td> <td class="tdc">167.9</td>
+      <td class="tdc">350</td> <td class="tdc">193.8</td>
+      <td class="tdc">393</td> <td class="tdc">220.5</td>
+   </tr><tr>
+      <td class="tdc">265</td> <td class="tdc">143.2</td>
+      <td class="tdc">308</td> <td class="tdc">168.5</td>
+      <td class="tdc">351</td> <td class="tdc">194.4</td>
+      <td class="tdc">394</td> <td class="tdc">221.2</td>
+   </tr><tr>
+      <td class="tdc">266</td> <td class="tdc">143.8</td>
+      <td class="tdc">309</td> <td class="tdc">169.1</td>
+      <td class="tdc">352</td> <td class="tdc">195.0</td>
+      <td class="tdc">395</td> <td class="tdc">221.8</td>
+   </tr><tr>
+      <td class="tdc">267</td> <td class="tdc">144.4</td>
+      <td class="tdc">310</td> <td class="tdc">169.7</td>
+      <td class="tdc">353</td> <td class="tdc">195.6</td>
+      <td class="tdc">396</td> <td class="tdc">222.4</td>
+   </tr><tr>
+      <td class="tdc">268</td> <td class="tdc">144.9</td>
+      <td class="tdc">311</td> <td class="tdc">170.3</td>
+      <td class="tdc">354</td> <td class="tdc">196.2</td>
+      <td class="tdc">397</td> <td class="tdc">223.1</td>
+   </tr><tr>
+      <td class="tdc">269</td> <td class="tdc">145.5</td>
+      <td class="tdc">312</td> <td class="tdc">170.9</td>
+      <td class="tdc">355</td> <td class="tdc">196.8</td>
+      <td class="tdc">398</td> <td class="tdc">223.7</td>
+   </tr><tr>
+      <td class="tdc">270</td> <td class="tdc">146.1</td>
+      <td class="tdc">313</td> <td class="tdc">171.5</td>
+      <td class="tdc">356</td> <td class="tdc">197.4</td>
+      <td class="tdc">399</td> <td class="tdc">224.3</td>
+   </tr><tr>
+      <td class="tdc">271</td> <td class="tdc">146.7</td>
+      <td class="tdc">314</td> <td class="tdc">172.1</td>
+      <td class="tdc">357</td> <td class="tdc">198.0</td>
+      <td class="tdc">400</td> <td class="tdc">224.9</td>
+   </tr><tr>
+      <td class="tdc">272</td> <td class="tdc">147.2</td>
+      <td class="tdc">315</td> <td class="tdc">172.7</td>
+      <td class="tdc">358</td> <td class="tdc">198.6</td>
+      <td class="tdc">401</td> <td class="tdc">225.7</td>
+   </tr><tr>
+      <td class="tdc">273</td> <td class="tdc">147.8</td>
+      <td class="tdc">316</td> <td class="tdc">173.3</td>
+      <td class="tdc">359</td> <td class="tdc">199.2</td>
+      <td class="tdc">402</td> <td class="tdc">226.4</td>
+   </tr><tr>
+      <td class="tdc">274</td> <td class="tdc">148.4</td>
+      <td class="tdc">317</td> <td class="tdc">173.9</td>
+      <td class="tdc">360</td> <td class="tdc">199.8</td>
+      <td class="tdc">403</td> <td class="tdc">227.1</td>
+   </tr><tr>
+      <td class="tdc">275</td> <td class="tdc">149.0</td>
+      <td class="tdc">318</td> <td class="tdc">174.5</td>
+      <td class="tdc">361</td> <td class="tdc">200.4</td>
+      <td class="tdc">404</td> <td class="tdc">227.8</td>
+   </tr><tr>
+      <td class="tdc">276</td> <td class="tdc">149.5</td>
+      <td class="tdc">319</td> <td class="tdc">175.1</td>
+      <td class="tdc">362</td> <td class="tdc">201.1</td>
+      <td class="tdc">405</td> <td class="tdc">228.6</td>
+   </tr><tr>
+      <td class="tdc">277</td> <td class="tdc">150.1</td>
+      <td class="tdc">320</td> <td class="tdc">175.6</td>
+      <td class="tdc">363</td> <td class="tdc">201.7</td>
+      <td class="tdc">406</td> <td class="tdc">229.3</td>
+   </tr><tr>
+      <td class="tdc">278</td> <td class="tdc">150.7</td>
+      <td class="tdc">321</td> <td class="tdc">176.2</td>
+      <td class="tdc">364</td> <td class="tdc">202.3</td>
+      <td class="tdc">407</td> <td class="tdc">230.0</td>
+   </tr><tr class="bb">
+      <td class="tdc">279</td> <td class="tdc">151.3</td>
+      <td class="tdc">322</td> <td class="tdc">176.8</td>
+      <td class="tdc">365</td> <td class="tdc">203.0</td>
+      <td class="tdc">408</td> <td class="tdc">230.7</td>
+   </tr><tr>
+      <td class="tdc">280</td> <td class="tdc">151.9</td>
+      <td class="tdc">323</td> <td class="tdc">177.4</td>
+      <td class="tdc">366</td> <td class="tdc">203.6</td>
+      <td class="tdc">409</td> <td class="tdc">231.4</td>
+   </tr><tr>
+      <td class="tdc">281</td> <td class="tdc">152.5</td>
+      <td class="tdc">324</td> <td class="tdc">178.0</td>
+      <td class="tdc">367</td> <td class="tdc">204.2</td>
+      <td class="tdc">410</td> <td class="tdc">232.1</td>
+   </tr><tr>
+      <td class="tdc">282</td> <td class="tdc">153.1</td>
+      <td class="tdc">325</td> <td class="tdc">178.6</td>
+      <td class="tdc">368</td> <td class="tdc">204.8</td>
+      <td class="tdc">411</td> <td class="tdc">232.8</td>
+   </tr><tr>
+      <td class="tdc">283</td> <td class="tdc">153.7</td>
+      <td class="tdc">326</td> <td class="tdc">179.2</td>
+      <td class="tdc">369</td> <td class="tdc">205.5</td>
+      <td class="tdc">412</td> <td class="tdc">233.5</td>
+   </tr><tr>
+      <td class="tdc">284</td> <td class="tdc">154.3</td>
+      <td class="tdc">327</td> <td class="tdc">178.8</td>
+      <td class="tdc">370</td> <td class="tdc">206.1</td>
+      <td class="tdc">413</td> <td class="tdc">234.3</td>
+   </tr><tr>
+      <td class="tdc">285</td> <td class="tdc">154.9</td>
+      <td class="tdc">328</td> <td class="tdc">180.4</td>
+      <td class="tdc">371</td> <td class="tdc">206.7</td>
+      <td class="tdc">414</td> <td class="tdc">235.0</td>
+   </tr><tr>
+      <td class="tdc">286</td> <td class="tdc">155.5</td>
+      <td class="tdc">329</td> <td class="tdc">181.0</td>
+      <td class="tdc">372</td> <td class="tdc">207.3</td>
+      <td class="tdc">415</td> <td class="tdc">235.7</td>
+   </tr><tr>
+      <td class="tdc">287</td> <td class="tdc">156.1</td>
+      <td class="tdc">330</td> <td class="tdc">181.6</td>
+      <td class="tdc">373</td> <td class="tdc">208.0</td>
+      <td class="tdc">416</td> <td class="tdc">236.4</td>
+   </tr><tr>
+      <td class="tdc">288</td> <td class="tdc">156.7</td>
+      <td class="tdc">331</td> <td class="tdc">182.2</td>
+      <td class="tdc">374</td> <td class="tdc">208.6</td>
+      <td class="tdc">417</td> <td class="tdc">237.1</td>
+   </tr><tr>
+      <td class="tdc">289</td> <td class="tdc">157.2</td>
+      <td class="tdc">332</td> <td class="tdc">182.8</td>
+      <td class="tdc">375</td> <td class="tdc">209.2</td>
+      <td class="tdc">418</td> <td class="tdc">237.8</td>
+   </tr><tr>
+      <td class="tdc">290</td> <td class="tdc">157.8</td>
+      <td class="tdc">333</td> <td class="tdc">183.5</td>
+      <td class="tdc">376</td> <td class="tdc">209.9</td>
+      <td class="tdc">419</td> <td class="tdc">238.5</td>
+   </tr><tr>
+      <td class="tdc">291</td> <td class="tdc">158.4</td>
+      <td class="tdc">334</td> <td class="tdc">184.1</td>
+      <td class="tdc">377</td> <td class="tdc">210.5</td>
+      <td class="tdc">420</td> <td class="tdc">239.2</td>
+   </tr><tr>
+      <td class="tdc">292</td> <td class="tdc">159.0</td>
+      <td class="tdc">335</td> <td class="tdc">184.7</td>
+      <td class="tdc">378</td> <td class="tdc">211.1</td>
+      <td class="tdc">421</td> <td class="tdc">239.9</td>
+   </tr><tr>
+      <td class="tdc">293</td> <td class="tdc">159.6</td>
+      <td class="tdc">336</td> <td class="tdc">185.4</td>
+      <td class="tdc">379</td> <td class="tdc">211.7</td>
+      <td class="tdc">422</td> <td class="tdc">240.6</td>
+   </tr><tr>
+      <td class="tdc">294</td> <td class="tdc">160.2</td>
+      <td class="tdc">337</td> <td class="tdc">186.0</td>
+      <td class="tdc">380</td> <td class="tdc">212.4</td>
+      <td class="tdc">423</td> <td class="tdc">241.3</td>
+   </tr><tr>
+      <td class="tdc">295</td> <td class="tdc">160.8</td>
+      <td class="tdc">338</td> <td class="tdc">186.6</td>
+      <td class="tdc">381</td> <td class="tdc">213.0</td>
+      <td class="tdc">424</td> <td class="tdc">242.0</td>
+   </tr><tr>
+      <td class="tdc">296</td> <td class="tdc">161.4</td>
+      <td class="tdc">339</td> <td class="tdc">187.2</td>
+      <td class="tdc">382</td> <td class="tdc">213.6</td>
+      <td class="tdc">425</td> <td class="tdc">242.7</td>
+   </tr><tr>
+      <td class="tdc">297</td> <td class="tdc">162.0</td>
+      <td class="tdc">340</td> <td class="tdc">187.8</td>
+      <td class="tdc">383</td> <td class="tdc">214.3</td>
+      <td class="tdc">426</td> <td class="tdc">243.4</td>
+   </tr><tr>
+      <td class="tdc">298</td> <td class="tdc">162.6</td>
+      <td class="tdc">341</td> <td class="tdc">188.4</td>
+      <td class="tdc">384</td> <td class="tdc">214.9</td>
+      <td class="tdc">427</td> <td class="tdc">244.1</td>
+   </tr><tr>
+      <td class="tdc">299</td> <td class="tdc">163.2</td>
+      <td class="tdc">342</td> <td class="tdc">189.0</td>
+      <td class="tdc">385</td> <td class="tdc">215.5</td>
+      <td class="tdc">428</td> <td class="tdc">244.9</td>
+   </tr><tr>
+      <td class="tdc">300</td> <td class="tdc">163.8</td>
+      <td class="tdc">343</td> <td class="tdc">189.6</td>
+      <td class="tdc">386</td> <td class="tdc">216.1</td>
+      <td class="tdc">429</td> <td class="tdc">245.6</td>
+   </tr><tr>
+      <td class="tdc">301</td> <td class="tdc">164.4</td>
+      <td class="tdc">344</td> <td class="tdc">190.2</td>
+      <td class="tdc">387</td> <td class="tdc">216.8</td>
+      <td class="tdc">430</td> <td class="tdc">246.3</td>
+   </tr><tr>
+      <td class="tdc">302</td> <td class="tdc">165.0</td>
+      <td class="tdc">345</td> <td class="tdc">190.8</td>
+      <td class="tdc">388</td> <td class="tdc">217.4</td>
+      <td class="tdc">&nbsp;</td> <td class="tdc">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">303</td> <td class="tdc">165.6</td>
+      <td class="tdc">346</td> <td class="tdc">191.4</td>
+      <td class="tdc">389</td> <td class="tdc">218.0</td>
+      <td class="tdc">&nbsp;</td> <td class="tdc">&nbsp;</td>
+   </tr><tr class="bb">
+      <td class="tdc">304</td> <td class="tdc">166.2</td>
+      <td class="tdc">347</td> <td class="tdc">192.0</td>
+      <td class="tdc">390</td> <td class="tdc">218.7</td>
+      <td class="tdc">&nbsp;</td> <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p id="P_142"><span class="pagenum"><a id="Page_161"></a>[Pg 161]</span>
+<b>142. Table for the Determination of Invert Sugar (Reducing Sugars)
+in the Presence of Sucrose.</b>—The method adopted by the Association
+of Official Agricultural Chemists is essentially that proposed by
+Meissl and Hiller.<a id="FNanchor_108" href="#Footnote_108" class="fnanchor">[108]</a>
+Prepare a solution of the material to be examined in such a manner
+that it contains twenty grams of the mixed sugars in one hundred cubic
+centimeters, after clarification and the removal of the excess of lead.
+Prepare a series of solutions in large test tubes by adding one, two,
+three, four, five etc. cubic centimeters of this solution to each tube
+successively. Add five cubic centimeters of the mixed copper reagent
+to each, heat to boiling, boil two minutes and filter. Note the volume
+of sugar solution which gives the filtrate lightest in tint, but still
+distinctly blue. Place twenty times this volume of the sugar solution
+in a 100 cubic centimeter flask, dilute to the mark, and mix well. Use
+fifty cubic centimeters of the solution for the determination, which is
+conducted as already described, until the weight of copper is obtained.
+For the calculation of the results use the following formulas and table
+of factors of Meissl and Hiller:<a id="FNanchor_109" href="#Footnote_109" class="fnanchor">[109]</a></p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdr_wsp">Let&emsp;Cu =</td>
+      <td class="tdl">the weight of the copper obtained;</td>
+   </tr><tr>
+      <td class="tdr_wsp">P =</td>
+      <td class="tdl">the polarization of the sample;</td>
+   </tr><tr>
+      <td class="tdr_wsp">W =</td>
+      <td class="tdl">the weight of the sample in the fifty cubic</td>
+   </tr><tr>
+      <td class="tdr_wsp">&nbsp;</td>
+      <td class="tdl_ws1">centimeters of the solution used for determination;</td>
+   </tr><tr>
+      <td class="tdr_wsp">F =</td>
+      <td class="tdl">the factor obtained from the table for conversion</td>
+   </tr><tr>
+      <td class="tdr_wsp">&nbsp;</td>
+      <td class="tdl_ws1">of copper to invert sugar;</td>
+   </tr><tr>
+      <td class="tdr_wsp u">&nbsp;Cu&nbsp;</td>
+      <td class="tdl" rowspan="2">= approximate absolute weight of invert sugar = Z;</td>
+   </tr><tr>
+      <td class="tdr_ws1">2</td>
+   </tr><tr>
+      <td class="tdr_ws1">100 &nbsp;</td>
+      <td class="tdl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdr_wsp">Z &nbsp;× —— &nbsp;= &nbsp;</td>
+      <td class="tdl">approximate per cent of invert sugar = <i>y</i>;</td>
+   </tr><tr>
+      <td class="tdr_ws1">W&nbsp; &nbsp;</td>
+      <td class="tdl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdr_wsp u">&nbsp;100P&nbsp;</td>
+      <td class="tdl" rowspan="2">= R, relative number for sucrose;</td>
+   </tr><tr>
+      <td class="tdr_ws1">P + <i>y</i></td>
+   </tr><tr>
+      <td class="tdr_wsp">100 - R =</td>
+      <td class="tdl">I, relative number for invert sugar;</td>
+   </tr><tr>
+      <td class="tdr_wsp u">&nbsp;Cu&nbsp;</td>
+      <td class="tdl" rowspan="2">= per cent of invert sugar.</td>
+   </tr><tr>
+      <td class="tdr_ws1">W</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Z indicates the vertical column, and the ratio of R to I, the
+horizontal column of the table, which are to be used for the purpose of
+finding the factor (F) for calculating copper to invert sugar.
+<span class="pagenum"><a id="Page_162"></a>[Pg 162]</span></p>
+
+<p><i>Example</i>:—The polarization of a sugar is 86.4, and 3.256 grams
+of it (W) are equivalent to 0.290 gram of copper. Then:</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdc bb">Cu</td>
+      <td class="tdl" rowspan="2">&nbsp; = &nbsp;</td>
+      <td class="tdc bb">0.290</td>
+      <td class="tdl" rowspan="2">&nbsp; = &nbsp;0.145 = Z</td>
+   </tr><tr>
+      <td class="tdc">2</td>
+      <td class="tdc">2</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">Z × &nbsp;</td>
+      <td class="tdc bb">100</td>
+      <td class="tdl" rowspan="2">&nbsp; = 0.145 × &nbsp;</td>
+      <td class="tdc bb">100</td>
+      <td class="tdl" rowspan="2">&nbsp; = 4.45 = <i>y</i></td>
+   </tr><tr>
+      <td class="tdc">W</td>
+      <td class="tdc">3.256</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdc bb">100P</td>
+      <td class="tdl" rowspan="2">&nbsp; = &nbsp;</td>
+      <td class="tdc bb">8640</td>
+      <td class="tdl" rowspan="2">&nbsp; = &nbsp;95.1 = R</td>
+   </tr><tr>
+      <td class="tdc">P + <i>y</i></td>
+      <td class="tdc">86.4 + 4.45</td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="f105">100 - R = 100 - 95.1 = 4.9 = I</p>
+
+<p class="f105">R : I = 95.1 : 4.9</p>
+
+<p>By consulting the table it will be seen that the vertical column headed
+I = 150 is nearest to Z, 145, the horizontal column headed 95: 5 is
+nearest to the ratio of R to I, 95.1: 4.9. Where these columns meet we
+find the factor 51.2, which enters into the final calculation:</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdc bb">CuF</td>
+      <td class="tdl" rowspan="2">&nbsp; = &nbsp;</td>
+      <td class="tdc bb">.290 × 51.2</td>
+      <td class="tdl" rowspan="2">&nbsp; = &nbsp;4.56 the true per cent of invert sugar.</td>
+   </tr><tr>
+      <td class="tdc">W</td>
+      <td class="tdc">3.256</td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="f120"><b><span class="smcap">Meissl and Hiller’s Factors for the Determination of<br>
+More Than One Per Cent of Invert Sugar.</span></b></p>
+
+<table class="spb1">
+   <thead><tr class="fs_110">
+      <th class="tdc br bb" rowspan="2">Ratio of<br>sucrose<br>to invert<br>sugar =</th>
+      <th class="tdc bb" colspan="7">Approximate absolute weight of invert sugar = <i>Z</i>.</th>
+   </tr><tr class="bb">
+      <th class="tdc">I = 200</th>
+      <th class="tdc bl">I = 175</th>
+      <th class="tdc bl">I = 150</th>
+      <th class="tdc bl">I = 125</th>
+      <th class="tdc bl">I = 100</th>
+      <th class="tdc bl">I = 75</th>
+      <th class="tdc bl">I = 50</th>
+   </tr></thead>
+   <tbody><tr class="bb">
+      <td class="tdc">R : I.</td> <td class="tdc bl">mg.</td>
+      <td class="tdc bl">mg.</td> <td class="tdc bl">mg.</td>
+      <td class="tdc bl">mg.</td> <td class="tdc bl">mg.</td>
+      <td class="tdc bl">mg.</td> <td class="tdc bl">mg.</td>
+   </tr><tr>
+      <td class="tdc">&#8199;&#8199;0 : 100</td> <td class="tdc">56.4</td>
+      <td class="tdc">55.4</td> <td class="tdc">54.5</td>
+      <td class="tdc">53.8</td> <td class="tdc">53.2</td>
+      <td class="tdc">53.0</td> <td class="tdc">53.0</td>
+   </tr><tr>
+      <td class="tdc">10 : 90</td> <td class="tdc">56.3</td>
+      <td class="tdc">55.3</td> <td class="tdc">54.4</td>
+      <td class="tdc">53.8</td> <td class="tdc">53.2</td>
+      <td class="tdc">52.9</td> <td class="tdc">52.9</td>
+   </tr><tr>
+      <td class="tdc">20 : 80</td> <td class="tdc">56.2</td>
+      <td class="tdc">55.2</td> <td class="tdc">54.3</td>
+      <td class="tdc">53.7</td> <td class="tdc">53.2</td>
+      <td class="tdc">52.7</td> <td class="tdc">52.7</td>
+   </tr><tr>
+      <td class="tdc">30 : 70</td> <td class="tdc">56.1</td>
+      <td class="tdc">55.1</td> <td class="tdc">54.2</td>
+      <td class="tdc">53.7</td> <td class="tdc">53.2</td>
+      <td class="tdc">52.6</td> <td class="tdc">52.6</td>
+   </tr><tr>
+      <td class="tdc">40 : 60</td> <td class="tdc">55.9</td>
+      <td class="tdc">55.0</td> <td class="tdc">54.1</td>
+      <td class="tdc">53.6</td> <td class="tdc">53.1</td>
+      <td class="tdc">52.5</td> <td class="tdc">52.4</td>
+   </tr><tr>
+      <td class="tdc">50 : 50</td> <td class="tdc">55.7</td>
+      <td class="tdc">54.9</td> <td class="tdc">54.0</td>
+      <td class="tdc">53.5</td> <td class="tdc">53.1</td>
+      <td class="tdc">52.3</td> <td class="tdc">52.2</td>
+   </tr><tr>
+      <td class="tdc">60 : 40</td> <td class="tdc">55.6</td>
+      <td class="tdc">54.7</td> <td class="tdc">53.8</td>
+      <td class="tdc">53.2</td> <td class="tdc">52.8</td>
+      <td class="tdc">52.1</td> <td class="tdc">51.9</td>
+   </tr><tr>
+      <td class="tdc">70 : 30</td> <td class="tdc">55.5</td>
+      <td class="tdc">54.5</td> <td class="tdc">53.5</td>
+      <td class="tdc">52.9</td> <td class="tdc">52.5</td>
+      <td class="tdc">51.9</td> <td class="tdc">51.6</td>
+   </tr><tr>
+      <td class="tdc">80 : 20</td> <td class="tdc">55.4</td>
+      <td class="tdc">54.3</td> <td class="tdc">53.3</td>
+      <td class="tdc">52.7</td> <td class="tdc">52.2</td>
+      <td class="tdc">51.7</td> <td class="tdc">51.3</td>
+   </tr><tr>
+      <td class="tdc">90 : 10</td> <td class="tdc">54.6</td>
+      <td class="tdc">53.6</td> <td class="tdc">53.1</td>
+      <td class="tdc">52.6</td> <td class="tdc">52.1</td>
+      <td class="tdc">51.6</td> <td class="tdc">51.2</td>
+   </tr><tr>
+      <td class="tdc">91 : 9&#8199;</td> <td class="tdc">54.1</td>
+      <td class="tdc">53.6</td> <td class="tdc">52.6</td>
+      <td class="tdc">52.1</td> <td class="tdc">51.6</td>
+      <td class="tdc">51.2</td> <td class="tdc">50.7</td>
+   </tr><tr>
+      <td class="tdc">92 : 8&#8199;</td> <td class="tdc">53.6</td>
+      <td class="tdc">53.1</td> <td class="tdc">52.1</td>
+      <td class="tdc">51.6</td> <td class="tdc">51.2</td>
+      <td class="tdc">50.7</td> <td class="tdc">50.3</td>
+   </tr><tr>
+      <td class="tdc">93 : 7&#8199;</td> <td class="tdc">53.6</td>
+      <td class="tdc">53.1</td> <td class="tdc">52.1</td>
+      <td class="tdc">51.2</td> <td class="tdc">50.7</td>
+      <td class="tdc">50.3</td> <td class="tdc">49.8</td>
+   </tr><tr>
+      <td class="tdc">94 : 6&#8199;</td> <td class="tdc">53.1</td>
+      <td class="tdc">52.6</td> <td class="tdc">51.6</td>
+      <td class="tdc">50.7</td> <td class="tdc">50.3</td>
+      <td class="tdc">49.8</td> <td class="tdc">48.9</td>
+   </tr><tr>
+      <td class="tdc">95 : 5&#8199;</td> <td class="tdc">52.6</td>
+      <td class="tdc">52.1</td> <td class="tdc">51.2</td>
+      <td class="tdc">50.3</td> <td class="tdc">49.4</td>
+      <td class="tdc">48.9</td> <td class="tdc">48.5</td>
+   </tr><tr>
+      <td class="tdc">96 : 4&#8199;</td> <td class="tdc">52.1</td>
+      <td class="tdc">51.2</td> <td class="tdc">50.7</td>
+      <td class="tdc">49.8</td> <td class="tdc">48.9</td>
+      <td class="tdc">47.7</td> <td class="tdc">46.9</td>
+   </tr><tr>
+      <td class="tdc">97 : 3&#8199;</td> <td class="tdc">50.7</td>
+      <td class="tdc">50.3</td> <td class="tdc">49.8</td>
+      <td class="tdc">48.9</td> <td class="tdc">47.7</td>
+      <td class="tdc">46.2</td> <td class="tdc">45.1</td>
+   </tr><tr>
+      <td class="tdc">98 : 2&#8199;</td> <td class="tdc">49.9</td>
+      <td class="tdc">48.9</td> <td class="tdc">48.5</td>
+      <td class="tdc">47.3</td> <td class="tdc">45.8</td>
+      <td class="tdc">43.3</td> <td class="tdc">40.0</td>
+   </tr><tr class="bb">
+      <td class="tdc">99 : 1&#8199;</td> <td class="tdc">47.7</td>
+      <td class="tdc">47.3</td> <td class="tdc">46.5</td>
+      <td class="tdc">45.1</td> <td class="tdc">43.3</td>
+      <td class="tdc">41.2</td> <td class="tdc">38.1</td>
+   </tr>
+ </tbody>
+</table>
+
+<p id="P_143"><span class="pagenum"><a id="Page_163"></a>[Pg 163]</span>
+<b>143. Table for the Estimation of Milk Sugar.</b>—The solutions to
+be used for this table are the same as those employed in the preceding
+table for the estimation of invert sugar. The milk sugar is supposed to
+be in a pure form in solution before beginning the analysis. The method
+to be employed for milk will be given in the part devoted to dairy products.</p>
+
+<p>In the conduct of the work twenty-five cubic centimeters of the copper
+solution are mixed with an equal quantity of the alkaline tartrate
+mixture, and from twenty to one hundred cubic centimeters of the sugar
+solution added, according to its concentration. This solution should
+not contain less than seventy nor more than 306 milligrams of lactose.
+The volume is completed to 150 cubic centimeters with boiling water and
+kept in lively ebullition for six minutes. The rest of the operation is
+conducted in the manner already described. From the weight of copper
+obtained the quantity of milk sugar is determined by inspecting the
+table. It is recommended to use such a weight of milk sugar as will
+give about 200 milligrams of copper.</p>
+
+<p id="MILK_SUGAR" class="f120 spa1"><b><span class="smcap">Table for Determining Milk Sugar.</span></b></p>
+
+<ul class="index fs_110">
+<li class="isub3"><b>(A)</b> = Milligrams of copper.</li>
+<li class="isub3"><b>(B)</b> = Milligrams of milk sugar.</li>
+</ul>
+
+<table class="spb1">
+   <thead><tr class="fs_110">
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; &nbsp; (B) &nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; &nbsp; (B) &nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; (B) &nbsp;&nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; (B) &nbsp;&nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">100</td> <td class="tdc">&#8199;71.6</td>
+      <td class="tdc">120</td> <td class="tdc">&#8199;86.4</td>
+      <td class="tdc">140</td> <td class="tdc">101.3</td>
+      <td class="tdc">160</td> <td class="tdc">116.4</td>
+   </tr><tr>
+      <td class="tdc">101</td> <td class="tdc">&#8199;72.4</td>
+      <td class="tdc">121</td> <td class="tdc">&#8199;87.2</td>
+      <td class="tdc">141</td> <td class="tdc">102.0</td>
+      <td class="tdc">161</td> <td class="tdc">117.1</td>
+   </tr><tr>
+      <td class="tdc">102</td> <td class="tdc">&#8199;73.1</td>
+      <td class="tdc">122</td> <td class="tdc">&#8199;87.9</td>
+      <td class="tdc">142</td> <td class="tdc">102.8</td>
+      <td class="tdc">162</td> <td class="tdc">117.9</td>
+   </tr><tr>
+      <td class="tdc">103</td> <td class="tdc">&#8199;73.8</td>
+      <td class="tdc">123</td> <td class="tdc">&#8199;88.7</td>
+      <td class="tdc">143</td> <td class="tdc">103.5</td>
+      <td class="tdc">163</td> <td class="tdc">118.6</td>
+   </tr><tr>
+      <td class="tdc">104</td> <td class="tdc">&#8199;74.6</td>
+      <td class="tdc">124</td> <td class="tdc">&#8199;89.4</td>
+      <td class="tdc">144</td> <td class="tdc">104.3</td>
+      <td class="tdc">164</td> <td class="tdc">119.4</td>
+   </tr><tr>
+      <td class="tdc">105</td> <td class="tdc">&#8199;75.3</td>
+      <td class="tdc">125</td> <td class="tdc">&#8199;90.1</td>
+      <td class="tdc">145</td> <td class="tdc">105.1</td>
+      <td class="tdc">165</td> <td class="tdc">120.2</td>
+   </tr><tr>
+      <td class="tdc">106</td> <td class="tdc">&#8199;76.1</td>
+      <td class="tdc">126</td> <td class="tdc">&#8199;90.9</td>
+      <td class="tdc">146</td> <td class="tdc">105.8</td>
+      <td class="tdc">166</td> <td class="tdc">120.9</td>
+   </tr><tr>
+      <td class="tdc">107</td> <td class="tdc">&#8199;76.8</td>
+      <td class="tdc">127</td> <td class="tdc">&#8199;91.6</td>
+      <td class="tdc">147</td> <td class="tdc">106.6</td>
+      <td class="tdc">167</td> <td class="tdc">121.7</td>
+   </tr><tr>
+      <td class="tdc">108</td> <td class="tdc">&#8199;77.6</td>
+      <td class="tdc">128</td> <td class="tdc">&#8199;92.4</td>
+      <td class="tdc">148</td> <td class="tdc">107.3</td>
+      <td class="tdc">168</td> <td class="tdc">122.4</td>
+   </tr><tr class="bb">
+      <td class="tdc">109</td> <td class="tdc">&#8199;78.3</td>
+      <td class="tdc">129</td> <td class="tdc">&#8199;93.1</td>
+      <td class="tdc">149</td> <td class="tdc">108.1</td>
+      <td class="tdc">169</td> <td class="tdc">123.2</td>
+   </tr><tr>
+      <td class="tdc">110</td> <td class="tdc">&#8199;79.0</td>
+      <td class="tdc">130</td> <td class="tdc">&#8199;93.8</td>
+      <td class="tdc">150</td> <td class="tdc">108.8</td>
+      <td class="tdc">170</td> <td class="tdc">123.9</td>
+   </tr><tr>
+      <td class="tdc">111</td> <td class="tdc">&#8199;79.8</td>
+      <td class="tdc">131</td> <td class="tdc">&#8199;94.6</td>
+      <td class="tdc">151</td> <td class="tdc">109.6</td>
+      <td class="tdc">171</td> <td class="tdc">124.7</td>
+   </tr><tr>
+      <td class="tdc">112</td> <td class="tdc">&#8199;80.5</td>
+      <td class="tdc">132</td> <td class="tdc">&#8199;95.3</td>
+      <td class="tdc">152</td> <td class="tdc">110.3</td>
+      <td class="tdc">172</td> <td class="tdc">125.5</td>
+   </tr><tr>
+      <td class="tdc">113</td> <td class="tdc">&#8199;81.3</td>
+      <td class="tdc">133</td> <td class="tdc">&#8199;96.1</td>
+      <td class="tdc">153</td> <td class="tdc">111.1</td>
+      <td class="tdc">173</td> <td class="tdc">126.2</td>
+   </tr><tr>
+      <td class="tdc">114</td> <td class="tdc">&#8199;82.0</td>
+      <td class="tdc">134</td> <td class="tdc">&#8199;96.9</td>
+      <td class="tdc">154</td> <td class="tdc">111.9</td>
+      <td class="tdc">174</td> <td class="tdc">127.0</td>
+   </tr><tr>
+      <td class="tdc">115</td> <td class="tdc">&#8199;82.7</td>
+      <td class="tdc">135</td> <td class="tdc">&#8199;97.6</td>
+      <td class="tdc">155</td> <td class="tdc">112.6</td>
+      <td class="tdc">175</td> <td class="tdc">127.8</td>
+   </tr><tr>
+      <td class="tdc">116</td> <td class="tdc">&#8199;83.5</td>
+      <td class="tdc">136</td> <td class="tdc">&#8199;98.3</td>
+      <td class="tdc">156</td> <td class="tdc">113.4</td>
+      <td class="tdc">176</td> <td class="tdc">128.5</td>
+   </tr><tr>
+      <td class="tdc">117</td> <td class="tdc">&#8199;84.2</td>
+      <td class="tdc">137</td> <td class="tdc">&#8199;99.1</td>
+      <td class="tdc">157</td> <td class="tdc">114.1</td>
+      <td class="tdc">177</td> <td class="tdc">129.3</td>
+   </tr><tr>
+      <td class="tdc">118</td> <td class="tdc">&#8199;85.0</td>
+      <td class="tdc">138</td> <td class="tdc">&#8199;99.8</td>
+      <td class="tdc">158</td> <td class="tdc">114.9</td>
+      <td class="tdc">178</td> <td class="tdc">130.1</td>
+   </tr><tr>
+      <td class="tdc">119</td> <td class="tdc">&#8199;85.7</td>
+      <td class="tdc">139</td> <td class="tdc">100.5</td>
+      <td class="tdc">159</td> <td class="tdc">115.6</td>
+      <td class="tdc">179</td> <td class="tdc">130.8</td>
+   </tr><tr>
+      <td class="tdc" colspan="8">&nbsp;<span class="pagenum"><a id="Page_164"></a>[Pg 164]</span></td>
+   </tr><tr class="f110">
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+   </tr><tr>
+      <td class="tdc">180</td> <td class="tdc">131.6</td>
+      <td class="tdc">223</td> <td class="tdc">164.2</td>
+      <td class="tdc">266</td> <td class="tdc">197.2</td>
+      <td class="tdc">309</td> <td class="tdc">231.4</td>
+   </tr><tr>
+      <td class="tdc">181</td> <td class="tdc">132.4</td>
+      <td class="tdc">224</td> <td class="tdc">164.9</td>
+      <td class="tdc">267</td> <td class="tdc">198.0</td>
+      <td class="tdc">310</td> <td class="tdc">232.2</td>
+   </tr><tr>
+      <td class="tdc">182</td> <td class="tdc">133.1</td>
+      <td class="tdc">225</td> <td class="tdc">165.7</td>
+      <td class="tdc">268</td> <td class="tdc">198.8</td>
+      <td class="tdc">311</td> <td class="tdc">232.9</td>
+   </tr><tr>
+      <td class="tdc">183</td> <td class="tdc">133.9</td>
+      <td class="tdc">226</td> <td class="tdc">166.4</td>
+      <td class="tdc">269</td> <td class="tdc">199.5</td>
+      <td class="tdc">312</td> <td class="tdc">233.7</td>
+   </tr><tr>
+      <td class="tdc">184</td> <td class="tdc">134.7</td>
+      <td class="tdc">227</td> <td class="tdc">167.2</td>
+      <td class="tdc">270</td> <td class="tdc">200.3</td>
+      <td class="tdc">313</td> <td class="tdc">234.5</td>
+   </tr><tr>
+      <td class="tdc">185</td> <td class="tdc">135.4</td>
+      <td class="tdc">228</td> <td class="tdc">167.9</td>
+      <td class="tdc">271</td> <td class="tdc">201.1</td>
+      <td class="tdc">314</td> <td class="tdc">235.3</td>
+   </tr><tr>
+      <td class="tdc">186</td> <td class="tdc">136.2</td>
+      <td class="tdc">229</td> <td class="tdc">168.6</td>
+      <td class="tdc">272</td> <td class="tdc">201.9</td>
+      <td class="tdc">315</td> <td class="tdc">236.1</td>
+   </tr><tr>
+      <td class="tdc">187</td> <td class="tdc">137.0</td>
+      <td class="tdc">230</td> <td class="tdc">169.4</td>
+      <td class="tdc">273</td> <td class="tdc">202.7</td>
+      <td class="tdc">316</td> <td class="tdc">236.8</td>
+   </tr><tr>
+      <td class="tdc">188</td> <td class="tdc">137.7</td>
+      <td class="tdc">231</td> <td class="tdc">170.1</td>
+      <td class="tdc">274</td> <td class="tdc">203.5</td>
+      <td class="tdc">317</td> <td class="tdc">237.6</td>
+   </tr><tr>
+      <td class="tdc">189</td> <td class="tdc">138.5</td>
+      <td class="tdc">232</td> <td class="tdc">170.9</td>
+      <td class="tdc">275</td> <td class="tdc">204.3</td>
+      <td class="tdc">318</td> <td class="tdc">238.4</td>
+   </tr><tr>
+      <td class="tdc">190</td> <td class="tdc">139.3</td>
+      <td class="tdc">233</td> <td class="tdc">171.6</td>
+      <td class="tdc">276</td> <td class="tdc">205.1</td>
+      <td class="tdc">319</td> <td class="tdc">239.2</td>
+   </tr><tr>
+      <td class="tdc">191</td> <td class="tdc">140.0</td>
+      <td class="tdc">234</td> <td class="tdc">172.4</td>
+      <td class="tdc">277</td> <td class="tdc">205.9</td>
+      <td class="tdc">320</td> <td class="tdc">240.0</td>
+   </tr><tr>
+      <td class="tdc">192</td> <td class="tdc">140.8</td>
+      <td class="tdc">235</td> <td class="tdc">173.1</td>
+      <td class="tdc">278</td> <td class="tdc">206.7</td>
+      <td class="tdc">321</td> <td class="tdc">240.7</td>
+   </tr><tr>
+      <td class="tdc">193</td> <td class="tdc">141.6</td>
+      <td class="tdc">236</td> <td class="tdc">173.9</td>
+      <td class="tdc">279</td> <td class="tdc">207.5</td>
+      <td class="tdc">322</td> <td class="tdc">241.5</td>
+   </tr><tr>
+      <td class="tdc">194</td> <td class="tdc">142.3</td>
+      <td class="tdc">237</td> <td class="tdc">174.6</td>
+      <td class="tdc">280</td> <td class="tdc">208.3</td>
+      <td class="tdc">323</td> <td class="tdc">242.3</td>
+   </tr><tr>
+      <td class="tdc">195</td> <td class="tdc">143.1</td>
+      <td class="tdc">238</td> <td class="tdc">175.4</td>
+      <td class="tdc">281</td> <td class="tdc">209.1</td>
+      <td class="tdc">324</td> <td class="tdc">243.1</td>
+   </tr><tr>
+      <td class="tdc">196</td> <td class="tdc">143.9</td>
+      <td class="tdc">239</td> <td class="tdc">176.2</td>
+      <td class="tdc">282</td> <td class="tdc">209.9</td>
+      <td class="tdc">325</td> <td class="tdc">243.9</td>
+   </tr><tr>
+      <td class="tdc">197</td> <td class="tdc">144.6</td>
+      <td class="tdc">240</td> <td class="tdc">176.9</td>
+      <td class="tdc">283</td> <td class="tdc">210.7</td>
+      <td class="tdc">326</td> <td class="tdc">244.6</td>
+   </tr><tr>
+      <td class="tdc">198</td> <td class="tdc">145.4</td>
+      <td class="tdc">241</td> <td class="tdc">177.7</td>
+      <td class="tdc">284</td> <td class="tdc">211.5</td>
+      <td class="tdc">327</td> <td class="tdc">245.4</td>
+   </tr><tr class="bb">
+      <td class="tdc">199</td> <td class="tdc">146.2</td>
+      <td class="tdc">242</td> <td class="tdc">178.5</td>
+      <td class="tdc">285</td> <td class="tdc">212.3</td>
+      <td class="tdc">328</td> <td class="tdc">246.2</td>
+   </tr><tr>
+      <td class="tdc">200</td> <td class="tdc">146.9</td>
+      <td class="tdc">243</td> <td class="tdc">179.3</td>
+      <td class="tdc">286</td> <td class="tdc">213.1</td>
+      <td class="tdc">329</td> <td class="tdc">247.0</td>
+   </tr><tr>
+      <td class="tdc">201</td> <td class="tdc">147.7</td>
+      <td class="tdc">244</td> <td class="tdc">180.1</td>
+      <td class="tdc">287</td> <td class="tdc">213.9</td>
+      <td class="tdc">330</td> <td class="tdc">247.7</td>
+   </tr><tr>
+      <td class="tdc">202</td> <td class="tdc">148.5</td>
+      <td class="tdc">245</td> <td class="tdc">180.8</td>
+      <td class="tdc">288</td> <td class="tdc">214.7</td>
+      <td class="tdc">331</td> <td class="tdc">248.5</td>
+   </tr><tr>
+      <td class="tdc">203</td> <td class="tdc">149.2</td>
+      <td class="tdc">246</td> <td class="tdc">181.6</td>
+      <td class="tdc">289</td> <td class="tdc">215.5</td>
+      <td class="tdc">332</td> <td class="tdc">249.2</td>
+   </tr><tr>
+      <td class="tdc">204</td> <td class="tdc">150.0</td>
+      <td class="tdc">247</td> <td class="tdc">182.4</td>
+      <td class="tdc">290</td> <td class="tdc">216.3</td>
+      <td class="tdc">333</td> <td class="tdc">250.0</td>
+   </tr><tr>
+      <td class="tdc">205</td> <td class="tdc">150.7</td>
+      <td class="tdc">248</td> <td class="tdc">183.2</td>
+      <td class="tdc">291</td> <td class="tdc">217.1</td>
+      <td class="tdc">334</td> <td class="tdc">250.8</td>
+   </tr><tr>
+      <td class="tdc">206</td> <td class="tdc">151.5</td>
+      <td class="tdc">249</td> <td class="tdc">184.0</td>
+      <td class="tdc">292</td> <td class="tdc">217.9</td>
+      <td class="tdc">335</td> <td class="tdc">251.6</td>
+   </tr><tr>
+      <td class="tdc">207</td> <td class="tdc">152.2</td>
+      <td class="tdc">250</td> <td class="tdc">184.8</td>
+      <td class="tdc">293</td> <td class="tdc">218.7</td>
+      <td class="tdc">336</td> <td class="tdc">252.5</td>
+   </tr><tr>
+      <td class="tdc">208</td> <td class="tdc">153.0</td>
+      <td class="tdc">251</td> <td class="tdc">185.5</td>
+      <td class="tdc">294</td> <td class="tdc">219.5</td>
+      <td class="tdc">337</td> <td class="tdc">253.3</td>
+   </tr><tr>
+      <td class="tdc">209</td> <td class="tdc">153.7</td>
+      <td class="tdc">252</td> <td class="tdc">186.3</td>
+      <td class="tdc">295</td> <td class="tdc">220.3</td>
+      <td class="tdc">338</td> <td class="tdc">254.1</td>
+   </tr><tr>
+      <td class="tdc">210</td> <td class="tdc">154.5</td>
+      <td class="tdc">253</td> <td class="tdc">187.1</td>
+      <td class="tdc">296</td> <td class="tdc">221.1</td>
+      <td class="tdc">339</td> <td class="tdc">254.9</td>
+   </tr><tr>
+      <td class="tdc">211</td> <td class="tdc">155.2</td>
+      <td class="tdc">254</td> <td class="tdc">187.9</td>
+      <td class="tdc">297</td> <td class="tdc">221.9</td>
+      <td class="tdc">340</td> <td class="tdc">255.7</td>
+   </tr><tr>
+      <td class="tdc">212</td> <td class="tdc">156.0</td>
+      <td class="tdc">255</td> <td class="tdc">188.7</td>
+      <td class="tdc">298</td> <td class="tdc">222.7</td>
+      <td class="tdc">341</td> <td class="tdc">256.5</td>
+   </tr><tr>
+      <td class="tdc">213</td> <td class="tdc">156.7</td>
+      <td class="tdc">256</td> <td class="tdc">189.4</td>
+      <td class="tdc">299</td> <td class="tdc">223.5</td>
+      <td class="tdc">342</td> <td class="tdc">257.4</td>
+   </tr><tr>
+      <td class="tdc">214</td> <td class="tdc">157.5</td>
+      <td class="tdc">257</td> <td class="tdc">190.2</td>
+      <td class="tdc">300</td> <td class="tdc">224.4</td>
+      <td class="tdc">343</td> <td class="tdc">258.2</td>
+   </tr><tr>
+      <td class="tdc">215</td> <td class="tdc">158.2</td>
+      <td class="tdc">258</td> <td class="tdc">191.0</td>
+      <td class="tdc">301</td> <td class="tdc">225.2</td>
+      <td class="tdc">344</td> <td class="tdc">259.0</td>
+   </tr><tr>
+      <td class="tdc">216</td> <td class="tdc">159.0</td>
+      <td class="tdc">259</td> <td class="tdc">191.8</td>
+      <td class="tdc">302</td> <td class="tdc">225.9</td>
+      <td class="tdc">345</td> <td class="tdc">259.8</td>
+   </tr><tr>
+      <td class="tdc">217</td> <td class="tdc">159.7</td>
+      <td class="tdc">260</td> <td class="tdc">192.5</td>
+      <td class="tdc">303</td> <td class="tdc">226.7</td>
+      <td class="tdc">346</td> <td class="tdc">260.6</td>
+   </tr><tr>
+      <td class="tdc">218</td> <td class="tdc">160.4</td>
+      <td class="tdc">261</td> <td class="tdc">193.3</td>
+      <td class="tdc">304</td> <td class="tdc">227.5</td>
+      <td class="tdc">347</td> <td class="tdc">261.4</td>
+   </tr><tr>
+      <td class="tdc">219</td> <td class="tdc">161.2</td>
+      <td class="tdc">262</td> <td class="tdc">194.1</td>
+      <td class="tdc">305</td> <td class="tdc">228.3</td>
+      <td class="tdc">348</td> <td class="tdc">262.3</td>
+   </tr><tr>
+      <td class="tdc">220</td> <td class="tdc">161.9</td>
+      <td class="tdc">263</td> <td class="tdc">194.9</td>
+      <td class="tdc">306</td> <td class="tdc">229.1</td>
+      <td class="tdc">349</td> <td class="tdc">263.1</td>
+   </tr><tr>
+      <td class="tdc">221</td> <td class="tdc">162.7</td>
+      <td class="tdc">264</td> <td class="tdc">195.7</td>
+      <td class="tdc">307</td> <td class="tdc">229.8</td>
+      <td class="tdc">350</td> <td class="tdc">263.9</td>
+   </tr><tr>
+      <td class="tdc">222</td> <td class="tdc">163.4</td>
+      <td class="tdc">265</td> <td class="tdc">196.4</td>
+      <td class="tdc">308</td> <td class="tdc">230.6</td>
+      <td class="tdc">351</td> <td class="tdc">264.7</td>
+   </tr><tr>
+      <td class="tdc" colspan="8">&nbsp;<span class="pagenum"><a id="Page_165"></a>[Pg 165]</span></td>
+   </tr><tr class="f110">
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+   </tr><tr>
+      <td class="tdc">352</td> <td class="tdc">265.5</td>
+      <td class="tdc">365</td> <td class="tdc">276.2</td>
+      <td class="tdc">377</td> <td class="tdc">286.5</td>
+      <td class="tdc">389</td> <td class="tdc">296.8</td>
+   </tr><tr>
+      <td class="tdc">353</td> <td class="tdc">266.3</td>
+      <td class="tdc">366</td> <td class="tdc">277.1</td>
+      <td class="tdc">378</td> <td class="tdc">287.4</td>
+      <td class="tdc">390</td> <td class="tdc">297.7</td>
+   </tr><tr>
+      <td class="tdc">354</td> <td class="tdc">267.2</td>
+      <td class="tdc">367</td> <td class="tdc">277.9</td>
+      <td class="tdc">379</td> <td class="tdc">288.2</td>
+      <td class="tdc">391</td> <td class="tdc">298.5</td>
+   </tr><tr>
+      <td class="tdc">355</td> <td class="tdc">268.0</td>
+      <td class="tdc">368</td> <td class="tdc">278.8</td>
+      <td class="tdc">380</td> <td class="tdc">289.1</td>
+      <td class="tdc">392</td> <td class="tdc">299.4</td>
+   </tr><tr>
+      <td class="tdc">356</td> <td class="tdc">268.8</td>
+      <td class="tdc">369</td> <td class="tdc">279.6</td>
+      <td class="tdc">381</td> <td class="tdc">289.9</td>
+      <td class="tdc">393</td> <td class="tdc">300.3</td>
+   </tr><tr>
+      <td class="tdc">357</td> <td class="tdc">269.6</td>
+      <td class="tdc">370</td> <td class="tdc">280.5</td>
+      <td class="tdc">382</td> <td class="tdc">290.8</td>
+      <td class="tdc">394</td> <td class="tdc">301.1</td>
+   </tr><tr>
+      <td class="tdc">358</td> <td class="tdc">270.4</td>
+      <td class="tdc">371</td> <td class="tdc">281.4</td>
+      <td class="tdc">383</td> <td class="tdc">291.7</td>
+      <td class="tdc">395</td> <td class="tdc">302.0</td>
+   </tr><tr>
+      <td class="tdc">359</td> <td class="tdc">271.2</td>
+      <td class="tdc">372</td> <td class="tdc">282.2</td>
+      <td class="tdc">384</td> <td class="tdc">292.5</td>
+      <td class="tdc">396</td> <td class="tdc">302.8</td>
+   </tr><tr>
+      <td class="tdc">360</td> <td class="tdc">272.1</td>
+      <td class="tdc">373</td> <td class="tdc">283.1</td>
+      <td class="tdc">385</td> <td class="tdc">293.4</td>
+      <td class="tdc">397</td> <td class="tdc">303.7</td>
+   </tr><tr>
+      <td class="tdc">361</td> <td class="tdc">272.9</td>
+      <td class="tdc">374</td> <td class="tdc">283.9</td>
+      <td class="tdc">386</td> <td class="tdc">294.2</td>
+      <td class="tdc">398</td> <td class="tdc">304.6</td>
+   </tr><tr>
+      <td class="tdc">362</td> <td class="tdc">273.7</td>
+      <td class="tdc">375</td> <td class="tdc">284.8</td>
+      <td class="tdc">387</td> <td class="tdc">295.1</td>
+      <td class="tdc">399</td> <td class="tdc">305.4</td>
+   </tr><tr>
+      <td class="tdc">363</td> <td class="tdc">274.5</td>
+      <td class="tdc">376</td> <td class="tdc">285.7</td>
+      <td class="tdc">388</td> <td class="tdc">296.0</td>
+      <td class="tdc">400</td> <td class="tdc">306.3</td>
+   </tr><tr>
+      <td class="tdc bb">364</td> <td class="tdc bb">275.3</td>
+      <td class="tdc bb" colspan="6">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>144. Table for the Determination of Maltose.</b>—The copper and
+alkaline solutions employed for the oxidation of maltose are the same
+as those used for invert and milk sugars.</p>
+
+<p>In the manipulation twenty-five cubic centimeters each of the copper
+and alkali solutions are mixed and boiled and an equal volume of the
+maltose solution added, which should not contain more than one per
+cent of the sugar. The boiling is continued for four minutes, an equal
+volume of cold recently boiled water added, the cuprous oxid separated
+by filtration and the metallic copper obtained in the manner already
+described. The weight of maltose oxidized is then ascertained from the table.</p>
+
+<ul class="index">
+<li class="isub2"><i>Example.</i> Weight of impure maltose taken, ten grams to a liter:</li>
+<li class="isub6">Quantity used, twenty-five cubic centimeters:</li>
+<li class="isub6">Weight of copper obtained 268 milligrams:</li>
+<li class="isub6">Weight of maltose oxidized 237 milligrams:</li>
+<li class="isub6">Weight of impure maltose taken 250 milligrams:</li>
+<li class="isub6">Percentage of maltose in sample 94.8.</li>
+</ul>
+
+<p class="f120 spa1"><b><span class="smcap">Table for Maltose.</span></b></p>
+
+<ul class="index fs_110">
+<li class="isub3"><b>(A)</b> = Milligrams of copper.</li>
+<li class="isub3"><b>(B)</b> = Milligrams of maltose.</li>
+</ul>
+
+<table class="spb1">
+   <thead><tr class="fs_110">
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; &nbsp; (B) &nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; &nbsp; (B) &nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; (B) &nbsp;&nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; (B) &nbsp;&nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">&#8199;30</td> <td class="tdc">&#8199;25.3</td>
+      <td class="tdc">&#8199;35</td> <td class="tdc">&#8199;29.6</td>
+      <td class="tdc">&#8199;40</td> <td class="tdc">&#8199;33.9</td>
+      <td class="tdc">&#8199;45</td> <td class="tdc">&#8199;38.3</td>
+   </tr><tr>
+      <td class="tdc">&#8199;31</td> <td class="tdc">&#8199;26.1</td>
+      <td class="tdc">&#8199;36</td> <td class="tdc">&#8199;30.5</td>
+      <td class="tdc">&#8199;41</td> <td class="tdc">&#8199;34.8</td>
+      <td class="tdc">&#8199;46</td> <td class="tdc">&#8199;39.1</td>
+   </tr><tr>
+      <td class="tdc">&#8199;32</td> <td class="tdc">&#8199;27.0</td>
+      <td class="tdc">&#8199;37</td> <td class="tdc">&#8199;31.3</td>
+      <td class="tdc">&#8199;42</td> <td class="tdc">&#8199;35.7</td>
+      <td class="tdc">&#8199;47</td> <td class="tdc">&#8199;40.0</td>
+   </tr><tr>
+      <td class="tdc">&#8199;33</td> <td class="tdc">&#8199;27.9</td>
+      <td class="tdc">&#8199;38</td> <td class="tdc">&#8199;32.2</td>
+      <td class="tdc">&#8199;43</td> <td class="tdc">&#8199;36.5</td>
+      <td class="tdc">&#8199;48</td> <td class="tdc">&#8199;40.9</td>
+   </tr><tr>
+      <td class="tdc">&#8199;34</td> <td class="tdc">&#8199;28.7</td>
+      <td class="tdc">&#8199;39</td> <td class="tdc">&#8199;33.1</td>
+      <td class="tdc">&#8199;44</td> <td class="tdc">&#8199;37.4</td>
+      <td class="tdc">&#8199;49</td> <td class="tdc">&#8199;41.8</td>
+   </tr><tr>
+      <td class="tdc" colspan="8">&nbsp;<span class="pagenum"><a id="Page_166"></a>[Pg 166]</span></td>
+   </tr><tr class="f110">
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+   </tr><tr>
+      <td class="tdc">&#8199;50</td> <td class="tdc">&#8199;42.6</td>
+      <td class="tdc">&#8199;94</td> <td class="tdc">&#8199;81.2</td>
+      <td class="tdc">138</td> <td class="tdc">120.6</td>
+      <td class="tdc">182</td> <td class="tdc">160.1</td>
+   </tr><tr>
+      <td class="tdc">&#8199;51</td> <td class="tdc">&#8199;43.5</td>
+      <td class="tdc">&#8199;95</td> <td class="tdc">&#8199;82.1</td>
+      <td class="tdc">139</td> <td class="tdc">121.5</td>
+      <td class="tdc">183</td> <td class="tdc">160.9</td>
+   </tr><tr>
+      <td class="tdc">&#8199;52</td> <td class="tdc">&#8199;44.4</td>
+      <td class="tdc">&#8199;96</td> <td class="tdc">&#8199;83.0</td>
+      <td class="tdc">140</td> <td class="tdc">122.4</td>
+      <td class="tdc">184</td> <td class="tdc">161.8</td>
+   </tr><tr>
+      <td class="tdc">&#8199;53</td> <td class="tdc">&#8199;45.2</td>
+      <td class="tdc">&#8199;97</td> <td class="tdc">&#8199;83.9</td>
+      <td class="tdc">141</td> <td class="tdc">123.3</td>
+      <td class="tdc">185</td> <td class="tdc">162.7</td>
+   </tr><tr>
+      <td class="tdc">&#8199;54</td> <td class="tdc">&#8199;46.1</td>
+      <td class="tdc">&#8199;98</td> <td class="tdc">&#8199;84.8</td>
+      <td class="tdc">142</td> <td class="tdc">124.2</td>
+      <td class="tdc">186</td> <td class="tdc">163.6</td>
+   </tr><tr>
+      <td class="tdc">&#8199;55</td> <td class="tdc">&#8199;47.0</td>
+      <td class="tdc">&#8199;99</td> <td class="tdc">&#8199;85.7</td>
+      <td class="tdc">143</td> <td class="tdc">125.1</td>
+      <td class="tdc">187</td> <td class="tdc">164.5</td>
+   </tr><tr>
+      <td class="tdc">&#8199;56</td> <td class="tdc">&#8199;47.8</td>
+      <td class="tdc">100</td> <td class="tdc">&#8199;86.6</td>
+      <td class="tdc">144</td> <td class="tdc">126.0</td>
+      <td class="tdc">188</td> <td class="tdc">165.4</td>
+   </tr><tr>
+      <td class="tdc">&#8199;57</td> <td class="tdc">&#8199;48.7</td>
+      <td class="tdc">101</td> <td class="tdc">&#8199;87.5</td>
+      <td class="tdc">145</td> <td class="tdc">126.9</td>
+      <td class="tdc">189</td> <td class="tdc">166.3</td>
+   </tr><tr>
+      <td class="tdc">&#8199;58</td> <td class="tdc">&#8199;49.6</td>
+      <td class="tdc">102</td> <td class="tdc">&#8199;88.4</td>
+      <td class="tdc">146</td> <td class="tdc">127.8</td>
+      <td class="tdc">190</td> <td class="tdc">167.2</td>
+   </tr><tr class="bb">
+      <td class="tdc">&#8199;59</td> <td class="tdc">&#8199;50.4</td>
+      <td class="tdc">103</td> <td class="tdc">&#8199;89.2</td>
+      <td class="tdc">147</td> <td class="tdc">128.7</td>
+      <td class="tdc">191</td> <td class="tdc">168.1</td>
+   </tr><tr>
+      <td class="tdc">&#8199;60</td> <td class="tdc">&#8199;51.3</td>
+      <td class="tdc">104</td> <td class="tdc">&#8199;90.1</td>
+      <td class="tdc">148</td> <td class="tdc">129.6 </td>
+      <td class="tdc">192</td> <td class="tdc">169.0</td>
+   </tr><tr>
+      <td class="tdc">&#8199;61</td> <td class="tdc">&#8199;52.2</td>
+      <td class="tdc">105</td> <td class="tdc">&#8199;91.0</td>
+      <td class="tdc">149</td> <td class="tdc">130.5</td>
+      <td class="tdc">193</td> <td class="tdc">169.8</td>
+   </tr><tr>
+      <td class="tdc">&#8199;62</td> <td class="tdc">&#8199;53.1</td>
+      <td class="tdc">106</td> <td class="tdc">&#8199;91.9</td>
+      <td class="tdc">150</td> <td class="tdc">131.4</td>
+      <td class="tdc">194</td> <td class="tdc">170.7</td>
+   </tr><tr>
+      <td class="tdc">&#8199;63</td> <td class="tdc">&#8199;53.9</td>
+      <td class="tdc">107</td> <td class="tdc">&#8199;92.8</td>
+      <td class="tdc">151</td> <td class="tdc">132.3</td>
+      <td class="tdc">195</td> <td class="tdc">171.6</td>
+   </tr><tr>
+      <td class="tdc">&#8199;64</td> <td class="tdc">&#8199;54.8</td>
+      <td class="tdc">108</td> <td class="tdc">&#8199;93.7</td>
+      <td class="tdc">152</td> <td class="tdc">133.2</td>
+      <td class="tdc">196</td> <td class="tdc">172.5</td>
+   </tr><tr>
+      <td class="tdc">&#8199;65</td> <td class="tdc">&#8199;55.7</td>
+      <td class="tdc">109</td> <td class="tdc">&#8199;94.6</td>
+      <td class="tdc">153</td> <td class="tdc">134.1</td>
+      <td class="tdc">197</td> <td class="tdc">173.4</td>
+   </tr><tr>
+      <td class="tdc">&#8199;66</td> <td class="tdc">&#8199;56.6</td>
+      <td class="tdc">110</td> <td class="tdc">&#8199;95.5</td>
+      <td class="tdc">154</td> <td class="tdc">135.0</td>
+      <td class="tdc">198</td> <td class="tdc">174.3</td>
+   </tr><tr>
+      <td class="tdc">&#8199;67</td> <td class="tdc">&#8199;57.4</td>
+      <td class="tdc">111</td> <td class="tdc">&#8199;96.4</td>
+      <td class="tdc">155</td> <td class="tdc">135.9</td>
+      <td class="tdc">199</td> <td class="tdc">175.2</td>
+   </tr><tr>
+      <td class="tdc">&#8199;68</td> <td class="tdc">&#8199;58.3</td>
+      <td class="tdc">112</td> <td class="tdc">&#8199;97.3</td>
+      <td class="tdc">156</td> <td class="tdc">136.8</td>
+      <td class="tdc">200</td> <td class="tdc">176.1</td>
+   </tr><tr>
+      <td class="tdc">&#8199;69</td> <td class="tdc">&#8199;59.2</td>
+      <td class="tdc">113</td> <td class="tdc">&#8199;98.1</td>
+      <td class="tdc">157</td> <td class="tdc">137.7</td>
+      <td class="tdc">201</td> <td class="tdc">177.0</td>
+   </tr><tr>
+      <td class="tdc">&#8199;70</td> <td class="tdc">&#8199;60.1</td>
+      <td class="tdc">114</td> <td class="tdc">&#8199;99.0</td>
+      <td class="tdc">158</td> <td class="tdc">138.6</td>
+      <td class="tdc">202</td> <td class="tdc">177.9</td>
+   </tr><tr>
+      <td class="tdc">&#8199;71</td> <td class="tdc">&#8199;61.0</td>
+      <td class="tdc">115</td> <td class="tdc">&#8199;99.9</td>
+      <td class="tdc">159</td> <td class="tdc">139.5</td>
+      <td class="tdc">203</td> <td class="tdc">178.7</td>
+   </tr><tr>
+      <td class="tdc">&#8199;72</td> <td class="tdc">&#8199;61.8</td>
+      <td class="tdc">116</td> <td class="tdc">100.8</td>
+      <td class="tdc">160</td> <td class="tdc">140.4</td>
+      <td class="tdc">204</td> <td class="tdc">179.6</td>
+   </tr><tr>
+      <td class="tdc">&#8199;73</td> <td class="tdc">&#8199;62.7</td>
+      <td class="tdc">117</td> <td class="tdc">101.7</td>
+      <td class="tdc">161</td> <td class="tdc">141.3</td>
+      <td class="tdc">205</td> <td class="tdc">180.5</td>
+   </tr><tr>
+      <td class="tdc">&#8199;74</td> <td class="tdc">&#8199;63.6</td>
+      <td class="tdc">118</td> <td class="tdc">102.6</td>
+      <td class="tdc">162</td> <td class="tdc">142.2</td>
+      <td class="tdc">206</td> <td class="tdc">181.4</td>
+   </tr><tr>
+      <td class="tdc">&#8199;75</td> <td class="tdc">&#8199;64.5</td>
+      <td class="tdc">119</td> <td class="tdc">103.5</td>
+      <td class="tdc">163</td> <td class="tdc">143.1</td>
+      <td class="tdc">207</td> <td class="tdc">182.3</td>
+   </tr><tr>
+      <td class="tdc">&#8199;76</td> <td class="tdc">&#8199;65.4</td>
+      <td class="tdc">120</td> <td class="tdc">104.4</td>
+      <td class="tdc">164</td> <td class="tdc">144.0</td>
+      <td class="tdc">208</td> <td class="tdc">183.2</td>
+   </tr><tr>
+      <td class="tdc">&#8199;77</td> <td class="tdc">&#8199;66.2</td>
+      <td class="tdc">121</td> <td class="tdc">105.3</td>
+      <td class="tdc">165</td> <td class="tdc">144.9</td>
+      <td class="tdc">209</td> <td class="tdc">184.1</td>
+   </tr><tr>
+      <td class="tdc">&#8199;78</td> <td class="tdc">&#8199;67.1</td>
+      <td class="tdc">122</td> <td class="tdc">106.2</td>
+      <td class="tdc">166</td> <td class="tdc">145.8</td>
+      <td class="tdc">210</td> <td class="tdc">185.0</td>
+   </tr><tr class="bb">
+      <td class="tdc">&#8199;79</td> <td class="tdc">&#8199;68.0</td>
+      <td class="tdc">123</td> <td class="tdc">107.1</td>
+      <td class="tdc">167</td> <td class="tdc">146.7</td>
+      <td class="tdc">211</td> <td class="tdc">185.9</td>
+   </tr><tr>
+      <td class="tdc">&#8199;80</td> <td class="tdc">&#8199;68.9</td>
+      <td class="tdc">124</td> <td class="tdc">108.0</td>
+      <td class="tdc">168</td> <td class="tdc">147.6</td>
+      <td class="tdc">212</td> <td class="tdc">186.8</td>
+   </tr><tr>
+      <td class="tdc">&#8199;81</td> <td class="tdc">&#8199;69.7</td>
+      <td class="tdc">125</td> <td class="tdc">108.9</td>
+      <td class="tdc">169</td> <td class="tdc">148.5</td>
+      <td class="tdc">213</td> <td class="tdc">187.7</td>
+   </tr><tr>
+      <td class="tdc">&#8199;82</td> <td class="tdc">&#8199;70.6</td>
+      <td class="tdc">126</td> <td class="tdc">109.8</td>
+      <td class="tdc">170</td> <td class="tdc">149.4</td>
+      <td class="tdc">214</td> <td class="tdc">188.6</td>
+   </tr><tr>
+      <td class="tdc">&#8199;83</td> <td class="tdc">&#8199;71.5</td>
+      <td class="tdc">127</td> <td class="tdc">110.7</td>
+      <td class="tdc">171</td> <td class="tdc">150.3</td>
+      <td class="tdc">215</td> <td class="tdc">189.5</td>
+   </tr><tr>
+      <td class="tdc">&#8199;84</td> <td class="tdc">&#8199;72.4</td>
+      <td class="tdc">128</td> <td class="tdc">111.6</td>
+      <td class="tdc">172</td> <td class="tdc">151.2</td>
+      <td class="tdc">216</td> <td class="tdc">190.4</td>
+   </tr><tr>
+      <td class="tdc">&#8199;85</td> <td class="tdc">&#8199;73.2</td>
+      <td class="tdc">129</td> <td class="tdc">112.5</td>
+      <td class="tdc">173</td> <td class="tdc">152.0</td>
+      <td class="tdc">217</td> <td class="tdc">191.2</td>
+   </tr><tr>
+      <td class="tdc">&#8199;86</td> <td class="tdc">&#8199;74.1</td>
+      <td class="tdc">130</td> <td class="tdc">113.4</td>
+      <td class="tdc">174</td> <td class="tdc">152.9</td>
+      <td class="tdc">218</td> <td class="tdc">192.1</td>
+   </tr><tr>
+      <td class="tdc">&#8199;87</td> <td class="tdc">&#8199;75.0</td>
+      <td class="tdc">131</td> <td class="tdc">114.3</td>
+      <td class="tdc">175</td> <td class="tdc">153.8</td>
+      <td class="tdc">219</td> <td class="tdc">193.0</td>
+   </tr><tr>
+      <td class="tdc">&#8199;88</td> <td class="tdc">&#8199;75.9</td>
+      <td class="tdc">132</td> <td class="tdc">115.2</td>
+      <td class="tdc">176</td> <td class="tdc">154.7</td>
+      <td class="tdc">220</td> <td class="tdc">193.9</td>
+   </tr><tr>
+      <td class="tdc">&#8199;89</td> <td class="tdc">&#8199;76.8</td>
+      <td class="tdc">133</td> <td class="tdc">116.1</td>
+      <td class="tdc">177</td> <td class="tdc">155.6</td>
+      <td class="tdc">221</td> <td class="tdc">194.8</td>
+   </tr><tr>
+      <td class="tdc">&#8199;90</td> <td class="tdc">&#8199;77.7</td>
+      <td class="tdc">134</td> <td class="tdc">117.0</td>
+      <td class="tdc">178</td> <td class="tdc">156.5</td>
+      <td class="tdc">222</td> <td class="tdc">195.7</td>
+   </tr><tr>
+      <td class="tdc">&#8199;91</td> <td class="tdc">&#8199;78.6</td>
+      <td class="tdc">135</td> <td class="tdc">117.9</td>
+      <td class="tdc">179</td> <td class="tdc">157.4</td>
+      <td class="tdc">223</td> <td class="tdc">196.6</td>
+   </tr><tr>
+      <td class="tdc">&#8199;92</td> <td class="tdc">&#8199;79.5</td>
+      <td class="tdc">136</td> <td class="tdc">118.8</td>
+      <td class="tdc">180</td> <td class="tdc">158.3</td>
+      <td class="tdc">224</td> <td class="tdc">197.5</td>
+   </tr><tr>
+      <td class="tdc">&#8199;93</td> <td class="tdc">&#8199;80.3</td>
+      <td class="tdc">137</td> <td class="tdc">119.7</td>
+      <td class="tdc">181</td> <td class="tdc">159.2</td>
+      <td class="tdc">225</td> <td class="tdc">198.4</td>
+   </tr><tr>
+      <td class="tdc" colspan="8">&nbsp;<span class="pagenum"><a id="Page_167"></a>[Pg 167]</span></td>
+   </tr><tr class="f110">
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+   </tr><tr>
+      <td class="tdc">226</td> <td class="tdc">199.3</td>
+      <td class="tdc">245</td> <td class="tdc">216.3</td>
+      <td class="tdc">264</td> <td class="tdc">233.4</td>
+      <td class="tdc">283</td> <td class="tdc">250.4</td>
+   </tr><tr>
+      <td class="tdc">227</td> <td class="tdc">200.2</td>
+      <td class="tdc">246</td> <td class="tdc">217.2</td>
+      <td class="tdc">265</td> <td class="tdc">234.3</td>
+      <td class="tdc">284</td> <td class="tdc">251.3</td>
+   </tr><tr>
+      <td class="tdc">228</td> <td class="tdc">201.1</td>
+      <td class="tdc">247</td> <td class="tdc">218.1</td>
+      <td class="tdc">266</td> <td class="tdc">235.2</td>
+      <td class="tdc">285</td> <td class="tdc">252.2</td>
+   </tr><tr>
+      <td class="tdc">229</td> <td class="tdc">202.0</td>
+      <td class="tdc">248</td> <td class="tdc">219.0</td>
+      <td class="tdc">267</td> <td class="tdc">236.1</td>
+      <td class="tdc">286</td> <td class="tdc">253.1</td>
+   </tr><tr>
+      <td class="tdc">230</td> <td class="tdc">202.9</td>
+      <td class="tdc">249</td> <td class="tdc">219.9</td>
+      <td class="tdc">268</td> <td class="tdc">237.0</td>
+      <td class="tdc">287</td> <td class="tdc">254.0</td>
+   </tr><tr>
+      <td class="tdc">231</td> <td class="tdc">203.8</td>
+      <td class="tdc">250</td> <td class="tdc">220.8</td>
+      <td class="tdc">269</td> <td class="tdc">237.9</td>
+      <td class="tdc">288</td> <td class="tdc">254.9</td>
+   </tr><tr>
+      <td class="tdc">232</td> <td class="tdc">204.7</td>
+      <td class="tdc">251</td> <td class="tdc">221.7</td>
+      <td class="tdc">270</td> <td class="tdc">238.8</td>
+      <td class="tdc">289</td> <td class="tdc">255.8</td>
+   </tr><tr>
+      <td class="tdc">233</td> <td class="tdc">205.6</td>
+      <td class="tdc">252</td> <td class="tdc">222.6</td>
+      <td class="tdc">271</td> <td class="tdc">239.7</td>
+      <td class="tdc">290</td> <td class="tdc">256.6</td>
+   </tr><tr>
+      <td class="tdc">234</td> <td class="tdc">206.5</td>
+      <td class="tdc">253</td> <td class="tdc">223.5</td>
+      <td class="tdc">272</td> <td class="tdc">240.6</td>
+      <td class="tdc">291</td> <td class="tdc">257.5</td>
+   </tr><tr class="bb">
+      <td class="tdc">235</td> <td class="tdc">207.4</td>
+      <td class="tdc">254</td> <td class="tdc">224.4</td>
+      <td class="tdc">273</td> <td class="tdc">241.5</td>
+      <td class="tdc">292</td> <td class="tdc">258.4</td>
+   </tr><tr>
+      <td class="tdc">236</td> <td class="tdc">208.3</td>
+      <td class="tdc">255</td> <td class="tdc">225.3</td>
+      <td class="tdc">274</td> <td class="tdc">242.4</td>
+      <td class="tdc">293</td> <td class="tdc">259.3</td>
+   </tr><tr>
+      <td class="tdc">237</td> <td class="tdc">209.1</td>
+      <td class="tdc">256</td> <td class="tdc">226.2</td>
+      <td class="tdc">275</td> <td class="tdc">243.3</td>
+      <td class="tdc">294</td> <td class="tdc">260.2</td>
+   </tr><tr>
+      <td class="tdc">238</td> <td class="tdc">210.0</td>
+      <td class="tdc">257</td> <td class="tdc">227.1</td>
+      <td class="tdc">276</td> <td class="tdc">244.2</td>
+      <td class="tdc">295</td> <td class="tdc">261.1</td>
+   </tr><tr>
+      <td class="tdc">239</td> <td class="tdc">210.9</td>
+      <td class="tdc">258</td> <td class="tdc">228.0</td>
+      <td class="tdc">277</td> <td class="tdc">245.1</td>
+      <td class="tdc">296</td> <td class="tdc">262.0</td>
+   </tr><tr>
+      <td class="tdc">240</td> <td class="tdc">211.8</td>
+      <td class="tdc">259</td> <td class="tdc">228.9</td>
+      <td class="tdc">278</td> <td class="tdc">246.0</td>
+      <td class="tdc">297</td> <td class="tdc">262.8</td>
+   </tr><tr>
+      <td class="tdc">241</td> <td class="tdc">212.7</td>
+      <td class="tdc">260</td> <td class="tdc">229.8</td>
+      <td class="tdc">279</td> <td class="tdc">246.9</td>
+      <td class="tdc">298</td> <td class="tdc">263.7</td>
+   </tr><tr>
+      <td class="tdc">242</td> <td class="tdc">213.6</td>
+      <td class="tdc">261</td> <td class="tdc">230.7</td>
+      <td class="tdc">280</td> <td class="tdc">247.8</td>
+      <td class="tdc">299</td> <td class="tdc">264.6</td>
+   </tr><tr>
+      <td class="tdc">243</td> <td class="tdc">214.5</td>
+      <td class="tdc">262</td> <td class="tdc">231.6</td>
+      <td class="tdc">281</td> <td class="tdc">248.7</td>
+      <td class="tdc">300</td> <td class="tdc">265.5</td>
+   </tr><tr class="bb">
+      <td class="tdc">244</td> <td class="tdc">215.4</td>
+      <td class="tdc">263</td> <td class="tdc">232.5</td>
+      <td class="tdc">282</td> <td class="tdc">249.6</td>
+      <td class="tdc">&nbsp;</td> <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>145. Preparation of Levulose.</b>—It is not often that
+levulose, unmixed with other reducing sugars, is brought to the
+attention of the analyst. It probably does not exist in the unmixed
+state in any agricultural product. The easiest method of preparing it
+is by the hydrolysis of inulin. A nearly pure levulose has also lately
+been placed on the market under the name of diabetin. It is prepared
+from invert sugar.</p>
+
+<p>Inulin is prepared from dahlia bulbs by boiling the pulp with water
+and a trace of calcium carbonate. The extract is concentrated to
+a sirup and subjected to a freezing temperature to promote the
+crystallization of the inulin. The separated product is subjected to
+the above operations several times until it is pure and colorless. It
+is then washed with alcohol and ether and is reduced to a fine powder.
+Before the repeated treatment with water it is advisable to clarify
+the solution with lead subacetate. The lead is afterwards removed by
+hydrogen sulfid and the resultant acetic acid neutralized with calcium
+carbonate.</p>
+
+<p>By the action of hot dilute acids inulin is rapidly converted into
+levulose.</p>
+
+<p>Levulose may also be prepared from invert sugar, but in this case it
+<span class="pagenum"><a id="Page_168"></a>[Pg 168]</span>
+is difficult to free it from traces of dextrose. The most successful
+method consists in forming a lime compound with the invert sugar and
+separating the lime levulosate and dextrosate by their difference
+in solubility. The levulose salt is much less soluble than the
+corresponding compound of dextrose. In the manufacture of levulose
+from beet molasses, the latter is dissolved in six times its weight of
+water and inverted with a quantity of hydrochloric acid, proportioned
+to the quantity of ash present in the sample. After inversion the
+mixture is cooled to zero and the levulose precipitated by adding
+fine-ground lime. The dextrose and coloring matters in these conditions
+are not thrown down. The precipitated lime levulosate is separated by
+filtration and washed with ice-cold water. The lime salt is afterwards
+beaten to a cream with water and decomposed by carbon dioxid. The
+levulose, after filtration, is concentrated to the crystallizing
+point.<a id="FNanchor_110" href="#Footnote_110" class="fnanchor">[110]</a></p>
+
+<p><b>146. Estimation of Levulose.</b>—Levulose, when free of any
+admixture with other reducing sugars, may be determined by the copper
+method with the use of the subjoined table, prepared by Lehmann.<a id="FNanchor_111" href="#Footnote_111" class="fnanchor">[111]</a>
+The copper solution is the same as that used for invert sugar,
+<i>viz.</i>, 69.278 grams of pure copper sulfate in one liter. The
+alkali solution is prepared by dissolving 346 grams of rochelle salt
+and 250 grams of sodium hydroxid in water and completing the volume to
+one liter.</p>
+
+<p><i>Manipulation.</i>—Twenty-five cubic centimeters of each solution
+are mixed with fifty of water and boiled. To the boiling mixture
+twenty-five cubic centimeters of the levulose solution are added, which
+must not contain more than one per cent of the sugar. The boiling is
+then continued for fifteen minutes, and the cuprous oxid collected,
+washed and reduced to the metallic state in the usual way. The quantity
+of levulose is then determined by inspection from the table given
+below. Other methods of determining levulose in mixtures will be given
+further on.
+<span class="pagenum"><a id="Page_169"></a>[Pg 169]</span></p>
+
+<p class="f120 spa1"><b><span class="smcap">Table for the Estimation of Levulose.</span></b></p>
+
+<ul class="index fs_110">
+<li class="isub3"><b>(A)</b> = Milligrams of copper.</li>
+<li class="isub3"><b>(B)</b> = Milligrams of levulose.</li>
+</ul>
+
+<table class="spb1">
+   <thead><tr class="fs_110">
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; &nbsp; (B) &nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; &nbsp; (B) &nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; (B) &nbsp;&nbsp;</th>
+      <th class="tdc">&nbsp; (A) &nbsp;</th> <th class="tdc">&nbsp; (B) &nbsp;&nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">&#8199;20</td> <td class="tdc">&#8199;&#8199;7.15</td>
+      <td class="tdc">&#8199;62</td> <td class="tdc">&#8199;31.66</td>
+      <td class="tdc">104</td> <td class="tdc">&#8199;56.85</td>
+      <td class="tdc">146</td> <td class="tdc">&#8199;82.81</td>
+   </tr><tr>
+      <td class="tdc">&#8199;21</td> <td class="tdc">&#8199;&#8199;7.78</td>
+      <td class="tdc">&#8199;63</td> <td class="tdc">&#8199;32.25</td>
+      <td class="tdc">105</td> <td class="tdc">&#8199;57.46</td>
+      <td class="tdc">147</td> <td class="tdc">&#8199;83.43</td>
+   </tr><tr>
+      <td class="tdc">&#8199;22</td> <td class="tdc">&#8199;&#8199;8.41</td>
+      <td class="tdc">&#8199;64</td> <td class="tdc">&#8199;32.84</td>
+      <td class="tdc">106</td> <td class="tdc">&#8199;58.07</td>
+      <td class="tdc">148</td> <td class="tdc">&#8199;84.06</td>
+   </tr><tr>
+      <td class="tdc">&#8199;23</td> <td class="tdc">&#8199;&#8199;9.04</td>
+      <td class="tdc">&#8199;65</td> <td class="tdc">&#8199;33.43</td>
+      <td class="tdc">107</td> <td class="tdc">&#8199;58.68</td>
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+      <td class="tdc">174</td> <td class="tdc">100.54</td>
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+      <td class="tdc">175</td> <td class="tdc">101.18</td>
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+      <td class="tdc">176</td> <td class="tdc">101.82</td>
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+      <td class="tdc">177</td> <td class="tdc">102.46</td>
+   </tr><tr>
+      <td class="tdc">&#8199;52</td> <td class="tdc">&#8199;25.76</td>
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+      <td class="tdc">136</td> <td class="tdc">&#8199;76.53</td>
+      <td class="tdc">178</td> <td class="tdc">103.11</td>
+   </tr><tr>
+      <td class="tdc">&#8199;53</td> <td class="tdc">&#8199;26.35</td>
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+      <td class="tdc">137</td> <td class="tdc">&#8199;77.15</td>
+      <td class="tdc">179</td> <td class="tdc">103.75</td>
+   </tr><tr>
+      <td class="tdc">&#8199;54</td> <td class="tdc">&#8199;26.93</td>
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+      <td class="tdc">180</td> <td class="tdc">104.39</td>
+   </tr><tr>
+      <td class="tdc">&#8199;55</td> <td class="tdc">&#8199;27.52</td>
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+      <td class="tdc">139</td> <td class="tdc">&#8199;78.39</td>
+      <td class="tdc">181</td> <td class="tdc">105.04</td>
+   </tr><tr>
+      <td class="tdc">&#8199;56</td> <td class="tdc">&#8199;28.11</td>
+      <td class="tdc">&#8199;98</td> <td class="tdc">&#8199;53.19</td>
+      <td class="tdc">140</td> <td class="tdc">&#8199;79.01</td>
+      <td class="tdc">182</td> <td class="tdc">105.68</td>
+   </tr><tr>
+      <td class="tdc">&#8199;57</td> <td class="tdc">&#8199;28.70</td>
+      <td class="tdc">&#8199;99</td> <td class="tdc">&#8199;53.79</td>
+      <td class="tdc">141</td> <td class="tdc">&#8199;79.64</td>
+      <td class="tdc">183</td> <td class="tdc">106.33</td>
+   </tr><tr>
+      <td class="tdc">&#8199;58</td> <td class="tdc">&#8199;29.30</td>
+      <td class="tdc">100</td> <td class="tdc">&#8199;54.39</td>
+      <td class="tdc">142</td> <td class="tdc">&#8199;80.28</td>
+      <td class="tdc">184</td> <td class="tdc">106.97</td>
+   </tr><tr>
+      <td class="tdc">&#8199;59</td> <td class="tdc">&#8199;29.89</td>
+      <td class="tdc">101</td> <td class="tdc">&#8199;55.00</td>
+      <td class="tdc">143</td> <td class="tdc">&#8199;80.91</td>
+      <td class="tdc">185</td> <td class="tdc">107.62</td>
+   </tr><tr>
+      <td class="tdc">&#8199;60</td> <td class="tdc">&#8199;30.48</td>
+      <td class="tdc">102</td> <td class="tdc">&#8199;55.62</td>
+      <td class="tdc">144</td> <td class="tdc">&#8199;81.55</td>
+      <td class="tdc">186</td> <td class="tdc">108.27</td>
+   </tr><tr>
+      <td class="tdc">&#8199;61</td> <td class="tdc">&#8199;31.07</td>
+      <td class="tdc">103</td> <td class="tdc">&#8199;56.23</td>
+      <td class="tdc">145</td> <td class="tdc">&#8199;82.18</td>
+      <td class="tdc">187</td> <td class="tdc">108.92</td>
+   </tr><tr>
+      <td class="tdc" colspan="8">&nbsp;<span class="pagenum"><a id="Page_170"></a>[Pg 170]</span></td>
+   </tr><tr class="f110">
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+   </tr><tr>
+      <td class="tdc">188</td> <td class="tdc">109.56</td>
+      <td class="tdc">232</td> <td class="tdc">138.57</td>
+      <td class="tdc">276</td> <td class="tdc">168.68</td>
+      <td class="tdc">320</td> <td class="tdc">199.97</td>
+   </tr><tr>
+      <td class="tdc">189</td> <td class="tdc">110.21</td>
+      <td class="tdc">233</td> <td class="tdc">139.25</td>
+      <td class="tdc">277</td> <td class="tdc">169.37</td>
+      <td class="tdc">321</td> <td class="tdc">200.71</td>
+   </tr><tr>
+      <td class="tdc">190</td> <td class="tdc">110.86</td>
+      <td class="tdc">234</td> <td class="tdc">139.18</td>
+      <td class="tdc">278</td> <td class="tdc">170.06</td>
+      <td class="tdc">322</td> <td class="tdc">201.44</td>
+   </tr><tr>
+      <td class="tdc">191</td> <td class="tdc">111.50</td>
+      <td class="tdc">235</td> <td class="tdc">140.59</td>
+      <td class="tdc">279</td> <td class="tdc">170.75</td>
+      <td class="tdc">323</td> <td class="tdc">202.18</td>
+   </tr><tr>
+      <td class="tdc">192</td> <td class="tdc">112.14</td>
+      <td class="tdc">236</td> <td class="tdc">141.27</td>
+      <td class="tdc">280</td> <td class="tdc">171.44</td>
+      <td class="tdc">324</td> <td class="tdc">202.91</td>
+   </tr><tr>
+      <td class="tdc">193</td> <td class="tdc">112.78</td>
+      <td class="tdc">237</td> <td class="tdc">141.94</td>
+      <td class="tdc">281</td> <td class="tdc">172.14</td>
+      <td class="tdc">325</td> <td class="tdc">203.65</td>
+   </tr><tr>
+      <td class="tdc">194</td> <td class="tdc">113.42</td>
+      <td class="tdc">238</td> <td class="tdc">142.62</td>
+      <td class="tdc">282</td> <td class="tdc">172.85</td>
+      <td class="tdc">326</td> <td class="tdc">204.39</td>
+   </tr><tr>
+      <td class="tdc">195</td> <td class="tdc">114.06</td>
+      <td class="tdc">239</td> <td class="tdc">143.29</td>
+      <td class="tdc">283</td> <td class="tdc">173.55</td>
+      <td class="tdc">327</td> <td class="tdc">205.13</td>
+   </tr><tr>
+      <td class="tdc">196</td> <td class="tdc">114.72</td>
+      <td class="tdc">240</td> <td class="tdc">143.97</td>
+      <td class="tdc">284</td> <td class="tdc">174.26</td>
+      <td class="tdc">328</td> <td class="tdc">205.88</td>
+   </tr><tr>
+      <td class="tdc">197</td> <td class="tdc">115.38</td>
+      <td class="tdc">241</td> <td class="tdc">144.65</td>
+      <td class="tdc">285</td> <td class="tdc">174.96</td>
+      <td class="tdc">329</td> <td class="tdc">206.62</td>
+   </tr><tr>
+      <td class="tdc">198</td> <td class="tdc">116.04</td>
+      <td class="tdc">242</td> <td class="tdc">145.32</td>
+      <td class="tdc">286</td> <td class="tdc">175.67</td>
+      <td class="tdc">330</td> <td class="tdc">207.36</td>
+   </tr><tr class="bb">
+      <td class="tdc">199</td> <td class="tdc">116.70</td>
+      <td class="tdc">243</td> <td class="tdc">146.00</td>
+      <td class="tdc">287</td> <td class="tdc">176.39</td>
+      <td class="tdc">331</td> <td class="tdc">208.10</td>
+   </tr><tr>
+      <td class="tdc">200</td> <td class="tdc">117.36</td>
+      <td class="tdc">244</td> <td class="tdc">146.67</td>
+      <td class="tdc">288</td> <td class="tdc">177.10</td>
+      <td class="tdc">332</td> <td class="tdc">208.83</td>
+   </tr><tr>
+      <td class="tdc">201</td> <td class="tdc">118.02</td>
+      <td class="tdc">245</td> <td class="tdc">147.35</td>
+      <td class="tdc">289</td> <td class="tdc">177.82</td>
+      <td class="tdc">333</td> <td class="tdc">209.57</td>
+   </tr><tr>
+      <td class="tdc">202</td> <td class="tdc">118.68</td>
+      <td class="tdc">246</td> <td class="tdc">148.03</td>
+      <td class="tdc">290</td> <td class="tdc">178.53</td>
+      <td class="tdc">334</td> <td class="tdc">210.30</td>
+   </tr><tr>
+      <td class="tdc">203</td> <td class="tdc">119.33</td>
+      <td class="tdc">247</td> <td class="tdc">148.71</td>
+      <td class="tdc">291</td> <td class="tdc">179.24</td>
+      <td class="tdc">335</td> <td class="tdc">211.04</td>
+   </tr><tr>
+      <td class="tdc">204</td> <td class="tdc">119.99</td>
+      <td class="tdc">248</td> <td class="tdc">149.40</td>
+      <td class="tdc">292</td> <td class="tdc">179.95</td>
+      <td class="tdc">336</td> <td class="tdc">211.78</td>
+   </tr><tr>
+      <td class="tdc">205</td> <td class="tdc">120.65</td>
+      <td class="tdc">249</td> <td class="tdc">150.08</td>
+      <td class="tdc">293</td> <td class="tdc">180.65</td>
+      <td class="tdc">337</td> <td class="tdc">212.52</td>
+   </tr><tr>
+      <td class="tdc">206</td> <td class="tdc">121.30</td>
+      <td class="tdc">250</td> <td class="tdc">150.76</td>
+      <td class="tdc">294</td> <td class="tdc">181.63</td>
+      <td class="tdc">338</td> <td class="tdc">213.25</td>
+   </tr><tr>
+      <td class="tdc">207</td> <td class="tdc">121.96</td>
+      <td class="tdc">251</td> <td class="tdc">151.44</td>
+      <td class="tdc">295</td> <td class="tdc">182.07</td>
+      <td class="tdc">339</td> <td class="tdc">213.99</td>
+   </tr><tr>
+      <td class="tdc">208</td> <td class="tdc">122.61</td>
+      <td class="tdc">252</td> <td class="tdc">152.12</td>
+      <td class="tdc">296</td> <td class="tdc">182.78</td>
+      <td class="tdc">340</td> <td class="tdc">214.73</td>
+   </tr><tr>
+      <td class="tdc">209</td> <td class="tdc">123.27</td>
+      <td class="tdc">253</td> <td class="tdc">152.81</td>
+      <td class="tdc">297</td> <td class="tdc">183.49</td>
+      <td class="tdc">341</td> <td class="tdc">215.48</td>
+   </tr><tr>
+      <td class="tdc">210</td> <td class="tdc">123.92</td>
+      <td class="tdc">254</td> <td class="tdc">153.49</td>
+      <td class="tdc">298</td> <td class="tdc">184.21</td>
+      <td class="tdc">342</td> <td class="tdc">216.23</td>
+   </tr><tr>
+      <td class="tdc">211</td> <td class="tdc">124.58</td>
+      <td class="tdc">255</td> <td class="tdc">154.17</td>
+      <td class="tdc">299</td> <td class="tdc">184.92</td>
+      <td class="tdc">343</td> <td class="tdc">216.97</td>
+   </tr><tr>
+      <td class="tdc">212</td> <td class="tdc">125.24</td>
+      <td class="tdc">256</td> <td class="tdc">154.91</td>
+      <td class="tdc">300</td> <td class="tdc">185.63</td>
+      <td class="tdc">344</td> <td class="tdc">217.72</td>
+   </tr><tr>
+      <td class="tdc">213</td> <td class="tdc">125.90</td>
+      <td class="tdc">257</td> <td class="tdc">155.65</td>
+      <td class="tdc">301</td> <td class="tdc">186.35</td>
+      <td class="tdc">345</td> <td class="tdc">218.47</td>
+   </tr><tr>
+      <td class="tdc">214</td> <td class="tdc">126.56</td>
+      <td class="tdc">258</td> <td class="tdc">156.40</td>
+      <td class="tdc">302</td> <td class="tdc">187.06</td>
+      <td class="tdc">346</td> <td class="tdc">219.21</td>
+   </tr><tr>
+      <td class="tdc">215</td> <td class="tdc">127.22</td>
+      <td class="tdc">259</td> <td class="tdc">157.14</td>
+      <td class="tdc">303</td> <td class="tdc">187.78</td>
+      <td class="tdc">347</td> <td class="tdc">219.97</td>
+   </tr><tr>
+      <td class="tdc">216</td> <td class="tdc">127.85</td>
+      <td class="tdc">260</td> <td class="tdc">157.88</td>
+      <td class="tdc">304</td> <td class="tdc">188.49</td>
+      <td class="tdc">348</td> <td class="tdc">220.71</td>
+   </tr><tr>
+      <td class="tdc">217</td> <td class="tdc">128.48</td>
+      <td class="tdc">261</td> <td class="tdc">158.49</td>
+      <td class="tdc">305</td> <td class="tdc">189.21</td>
+      <td class="tdc">349</td> <td class="tdc">221.46</td>
+   </tr><tr>
+      <td class="tdc">218</td> <td class="tdc">129.10</td>
+      <td class="tdc">262</td> <td class="tdc">159.09</td>
+      <td class="tdc">306</td> <td class="tdc">189.93</td>
+      <td class="tdc">350</td> <td class="tdc">222.21</td>
+   </tr><tr class="bb">
+      <td class="tdc">219</td> <td class="tdc">129.73</td>
+      <td class="tdc">263</td> <td class="tdc">159.70</td>
+      <td class="tdc">307</td> <td class="tdc">190.65</td>
+      <td class="tdc">351</td> <td class="tdc">222.96</td>
+   </tr><tr>
+      <td class="tdc">220</td> <td class="tdc">130.36</td>
+      <td class="tdc">264</td> <td class="tdc">160.30</td>
+      <td class="tdc">308</td> <td class="tdc">191.37</td>
+      <td class="tdc">352</td> <td class="tdc">223.72</td>
+   </tr><tr>
+      <td class="tdc">221</td> <td class="tdc">131.07</td>
+      <td class="tdc">265</td> <td class="tdc">160.91</td>
+      <td class="tdc">309</td> <td class="tdc">192.09</td>
+      <td class="tdc">353</td> <td class="tdc">224.47</td>
+   </tr><tr>
+      <td class="tdc">222</td> <td class="tdc">131.77</td>
+      <td class="tdc">266</td> <td class="tdc">161.63</td>
+      <td class="tdc">310</td> <td class="tdc">192.81</td>
+      <td class="tdc">354</td> <td class="tdc">225.23</td>
+   </tr><tr>
+      <td class="tdc">223</td> <td class="tdc">132.48</td>
+      <td class="tdc">267</td> <td class="tdc">162.35</td>
+      <td class="tdc">311</td> <td class="tdc">193.53</td>
+      <td class="tdc">355</td> <td class="tdc">225.98</td>
+   </tr><tr>
+      <td class="tdc">224</td> <td class="tdc">133.18</td>
+      <td class="tdc">268</td> <td class="tdc">163.07</td>
+      <td class="tdc">312</td> <td class="tdc">194.25</td>
+      <td class="tdc">356</td> <td class="tdc">226.74</td>
+   </tr><tr>
+      <td class="tdc">225</td> <td class="tdc">133.89</td>
+      <td class="tdc">269</td> <td class="tdc">163.79</td>
+      <td class="tdc">313</td> <td class="tdc">194.97</td>
+      <td class="tdc">357</td> <td class="tdc">227.49</td>
+   </tr><tr>
+      <td class="tdc">226</td> <td class="tdc">134.56</td>
+      <td class="tdc">270</td> <td class="tdc">164.51</td>
+      <td class="tdc">314</td> <td class="tdc">195.69</td>
+      <td class="tdc">358</td> <td class="tdc">228.25</td>
+   </tr><tr>
+      <td class="tdc">227</td> <td class="tdc">135.23</td>
+      <td class="tdc">271</td> <td class="tdc">165.21</td>
+      <td class="tdc">315</td> <td class="tdc">196.41</td>
+      <td class="tdc">359</td> <td class="tdc">229.00</td>
+   </tr><tr>
+      <td class="tdc">228</td> <td class="tdc">135.89</td>
+      <td class="tdc">272</td> <td class="tdc">165.90</td>
+      <td class="tdc">316</td> <td class="tdc">197.12</td>
+      <td class="tdc">360</td> <td class="tdc">229.76</td>
+   </tr><tr>
+      <td class="tdc">229</td> <td class="tdc">136.89</td>
+      <td class="tdc">273</td> <td class="tdc">166.60</td>
+      <td class="tdc">317</td> <td class="tdc">197.83</td>
+      <td class="tdc">361</td> <td class="tdc">230.52</td>
+   </tr><tr>
+      <td class="tdc">230</td> <td class="tdc">137.23</td>
+      <td class="tdc">274</td> <td class="tdc">167.29</td>
+      <td class="tdc">318</td> <td class="tdc">198.55</td>
+      <td class="tdc">362</td> <td class="tdc">231.28</td>
+   </tr><tr>
+      <td class="tdc">231</td> <td class="tdc">137.90</td>
+      <td class="tdc">275</td> <td class="tdc">167.99</td>
+      <td class="tdc">319</td> <td class="tdc">199.26</td>
+      <td class="tdc">363</td> <td class="tdc">232.05</td>
+   </tr><tr>
+      <td class="tdc" colspan="8">&nbsp;<span class="pagenum"><a id="Page_171"></a>[Pg 171]</span></td>
+   </tr><tr class="f110">
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+      <td class="tdc">&nbsp; <b>(A)</b> &nbsp;</td> <td class="tdc">&nbsp; <b>(B)</b> &nbsp;</td>
+   </tr><tr>
+      <td class="tdc">364</td> <td class="tdc">232.81</td>
+      <td class="tdc">370</td> <td class="tdc">237.39</td>
+      <td class="tdc">376</td> <td class="tdc">241.87</td>
+      <td class="tdc">382</td> <td class="tdc">246.25</td>
+   </tr><tr>
+      <td class="tdc">365</td> <td class="tdc">233.57</td>
+      <td class="tdc">371</td> <td class="tdc">238.16</td>
+      <td class="tdc">377</td> <td class="tdc">242.51</td>
+      <td class="tdc">383</td> <td class="tdc">247.17</td>
+   </tr><tr>
+      <td class="tdc">366</td> <td class="tdc">234.33</td>
+      <td class="tdc">372</td> <td class="tdc">238.93</td>
+      <td class="tdc">378</td> <td class="tdc">243.15</td>
+      <td class="tdc">384</td> <td class="tdc">248.08</td>
+   </tr><tr>
+      <td class="tdc">367</td> <td class="tdc">235.10</td>
+      <td class="tdc">373</td> <td class="tdc">239.69</td>
+      <td class="tdc">379</td> <td class="tdc">243.79</td>
+      <td class="tdc">385</td> <td class="tdc">248.99</td>
+   </tr><tr>
+      <td class="tdc">368</td> <td class="tdc">235.86</td>
+      <td class="tdc">374</td> <td class="tdc">240.46</td>
+      <td class="tdc">380</td> <td class="tdc">244.43</td>
+      <td class="tdc">&nbsp;</td> <td class="tdc">&nbsp;</td>
+   </tr><tr class="bb">
+      <td class="tdc">369</td> <td class="tdc">236.63</td>
+      <td class="tdc">375</td> <td class="tdc">241.23</td>
+      <td class="tdc">381</td> <td class="tdc">245.34</td>
+      <td class="tdc">&nbsp;</td> <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p id="P_147"><b>147. Precipitation of Sugars with Phenylhydrazin</b>.—The
+combination of phenylhydrazin with aldehyds and ketones was first
+studied by Fischer, and the near relationship of these bodies to sugar
+soon led to the investigation of the compounds formed thereby with
+this reagent.<a id="FNanchor_112" href="#Footnote_112" class="fnanchor">[112]</a>
+Reducing sugars form with phenylhydrazin insoluble crystalline bodies,
+to which the name osazones has been given. The reaction which takes
+place is a double one and is represented by the following formulas:</p>
+
+<ul class="index">
+<li class="isub1">Dextrose.&emsp;Phenylhydrazin.&emsp;Dextrose-phenylhydrazone.</li>
+<li class="isub1">C₆H₁₂O₆&emsp;+&emsp;C₆H₅NH.NH₂&emsp;=&emsp;C₆H₁₂O₅.N.NHC₆H₅&nbsp; + &nbsp;H₂O</li>
+<li class="isub3">and&emsp;C₆H₁₂O₅.N.NHC₆H₅ + C₆H₅NH.NH₂ =</li>
+<li class="isub10">Phenyldextrosazone.</li>
+<li class="isub10">C₆H₁₀O₄(N.NHC₆H₅)₂ + 2H₂O.</li>
+</ul>
+
+<p>The dextrosazone is commonly called glucosazone. The osazones formed
+with the commonly occurring reducing sugars are crystalline, stable,
+insoluble bodies which can be easily separated from any attending
+impurities and identified by their melting points. Glucosazone melts at
+205°, lactosazone at 200° and maltosazone at 206°.</p>
+
+<p>The osazones are precipitated in the following way: The reducing sugar,
+in about ten per cent solution, is treated with an excess of the
+acetate of phenylhydrazin in acetic acid and warmed to from 75° to 85°.
+In a short time the separation is complete and the yellow precipitate
+formed is washed, dried and weighed. The sugar can be recovered from
+the osazone by decomposing it with strong hydrochloric acid by means
+of which the phenylhydrazin is displaced and a body, osone, is formed,
+which by treatment with zinc dust and acetic acid, is reduced to the
+<span class="pagenum"><a id="Page_172"></a>[Pg 172]</span>
+original sugar. The reactions which take place are represented by the
+following equations:<a id="FNanchor_113" href="#Footnote_113" class="fnanchor">[113]</a></p>
+
+<ul class="index">
+<li class="isub14">Glucososone.</li>
+<li class="isub1">C₆H₁₀O₄(N.NH.C₆H₅)₂ + 2H₂O = C₆H₁₀O₆ + 2C₆H₅N₂H₂</li>
+<li class="isub1">&nbsp;</li>
+<li class="isub10">&nbsp; Dextrose (Glucose).</li>
+<li class="isub4">C₆H₁₀O₆ + H₂ = C₆H₁₂O₆.</li>
+</ul>
+
+<p>For the complete precipitation of dextrose as osazone Lintner and
+Kröber show that the solution of dextrose should not contain more than
+one gram in 100 cubic centimeters. Twenty cubic centimeters containing
+0.2 gram dextrose should be used for the precipitation.<a id="FNanchor_114" href="#Footnote_114" class="fnanchor">[114]</a>
+To this solution should be added one gram of phenylhydrazin and one gram of
+fifty per cent acetic acid. The solution is then to be warmed for about
+two hours and the precipitate washed with from sixty to eighty cubic
+centimeters of hot water and dried for three hours at 105°. One part
+of the osazone is equivalent to one part of dextrose when maltose and
+dextrin are absent. When these are present the proportion is one part
+of osazone to 1.04 of dextrose. Where levulose is precipitated instead
+of dextrose 1.43 parts of the osazone are equal to one part of the sugar.</p>
+
+<p>Sucrose is scarcely at all precipitated as osazone until inverted.</p>
+
+<p>After inversion and precipitation as above, 1.33 parts osazone are
+equal to one part of sucrose.</p>
+
+<p>The reaction with phenylhydrazin has not been much used for quantitive
+estimations of sugars, but it has been found especially useful in
+identifying and separating reducing sugars. It is altogether probable,
+however, that in the near future phenylhydrazin will become a common
+reagent for sugar work.</p>
+
+<p>Maquenne has studied the action of phenylhydrazin on sugars and
+considers that this reaction offers the only known means of
+precipitating these bodies from solutions where they are found mixed
+with other substances.<a id="FNanchor_115" href="#Footnote_115" class="fnanchor">[115]</a>
+The osazones, which are thus obtained, are usually very slightly
+soluble in the ordinary reagents, for which reason it is easy to obtain
+them pure when there is at the disposition of the analyst a sufficient
+quantity of the material. But if the sugar to be studied is rare and
+if it contain, moreover, several distinct reducing bodies, the task
+is more delicate. It is easy then to confound several osazones which
+have almost identical points of fusion; for example, glucosazone with
+<span class="pagenum"><a id="Page_173"></a>[Pg 173]</span>
+galactosazone. Finally, it becomes impossible by the employment of
+phenylhydrazin to distinguish glucose, dextrose or mannose from
+levulose alone or mixed with its isomers. Indeed, these three sugars
+give, with the acetate of phenylhydrazin the same phenylglucosazone
+which melts at about 205°. It is noticed that the weights of osazones
+which are precipitated when different sugars are heated for the
+same time with the same quantity of the phenylhydrazin, vary within
+extremely wide limits. It is constant for each kind of sugar if the
+conditions under which the precipitation is made are rigorously the
+same. There is then, in the weight of the osazones produced, a new
+characteristic of particular value. The following numbers have been
+obtained by heating for one hour at 100°, one gram of sugar with 100
+cubic centimeters of water and five cubic centimeters of a solution
+containing forty grams of phenylhydrazin and forty grams of acetic acid
+per hundred. After cooling the liquid, the osazones are received upon
+a weighed filter, washed with 100 cubic centimeters of water, dried at
+110° and weighed. The weights of osazones obtained are given in the
+following table:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl" colspan="2">Character of the sugar.</td>
+      <td class="tdc" rowspan="11">&nbsp;&emsp;&nbsp;</td>
+      <td class="tdc">Weight of the<br> osazones. &nbsp;</td>
+   </tr><tr>
+      <td class="tdl" colspan="2">&nbsp;</td>
+      <td class="tdc">gram.</td>
+   </tr><tr>
+      <td class="tdl">Sorbine,</td>
+      <td class="tdl_wsp">crystallized</td>
+      <td class="tdc">0.82</td>
+   </tr><tr>
+      <td class="tdl">Levulose</td>
+      <td class="tdc">”</td>
+      <td class="tdc">0.70</td>
+   </tr><tr>
+      <td class="tdl">Xylose</td>
+      <td class="tdc">”</td>
+      <td class="tdc">0.40</td>
+   </tr><tr>
+      <td class="tdl">Glucose,</td>
+      <td class="tdl_wsp">anhydrous</td>
+      <td class="tdc">0.32</td>
+   </tr><tr>
+      <td class="tdl">Arabinose,</td>
+      <td class="tdl_wsp">crystallized</td>
+      <td class="tdc">0.27</td>
+   </tr><tr>
+      <td class="tdl">Galactose</td>
+      <td class="tdc">”</td>
+      <td class="tdc">0.23</td>
+   </tr><tr>
+      <td class="tdl">Rhamnose</td>
+      <td class="tdc">”</td>
+      <td class="tdc">0.15</td>
+   </tr><tr>
+      <td class="tdl">Lactose</td>
+      <td class="tdc">”</td>
+      <td class="tdc">0.11</td>
+   </tr><tr>
+      <td class="tdl">Maltose</td>
+      <td class="tdc">”</td>
+      <td class="tdc">0.11</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>With solutions twice as dilute as those above, the relative conditions
+are still more sensible, and the different sugars arrange themselves in
+the same order, with the exception of levulose, which shows a slight
+advantage over sorbine and acquires the first rank. From the above
+determinations, it is shown that levulose and sorbine give vastly
+greater quantities of osazones, under given conditions, than the other
+reducing sugars. It would be easy, therefore, to distinguish them by
+this reaction and to recognize their presence also even in very complex
+mixtures, where the polarimetric examination alone would furnish only
+uncertain indications.
+<span class="pagenum"><a id="Page_174"></a>[Pg 174]</span></p>
+
+<p>It is remarkable that these two sugars are the only ones among the
+isomers or the homologues of dextrose, actually known, which possess
+the functions of an acetone. They are not, however, easily confounded,
+since the glucosazone forms beautiful needles which are ordinarily
+visible to the naked eye, while the sorbinosazone is still oily and
+when heated never gives perfectly distinct crystals.</p>
+
+<p>This method also enables us to distinguish between dextrose and
+galactose, of which the osazone is well crystallized and melts at
+almost the same temperature as the phenylglucosazone. Finally, it
+is observed that the reducing sugars give less of osazones than the
+sugars which are not capable of hydrolysis, and consequently differ
+in their inversion products. It is specially noticed in this study of
+the polyglucoses (bioses, trioses), that this new method of employing
+the phenylhydrazin appears very advantageous. It is sufficient to
+compare the weights of the osazones to that which is given under the
+same conditions by a known glucose, in order to have a very certain
+verification of the probabilities of the result of the chemical or
+optical examination of the mixture which is under study. All the
+polyglucoses which have been examined from this point of view give
+very decided results. The numbers which follow have reference to one
+gram of sugar completely inverted by dilute sulfuric acid, dissolved
+in 100 cubic centimeters of water, and treated with two grams of
+phenylhydrazin, the same quantity of acetic acid, and five grams of
+crystallized sodium acetate. All these solutions have been compared
+with the artificial mixtures and corresponding glucoses, with the same
+quantities of the same reagents. The following are the results of the
+examination:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdl_ws1">Character of the sugar.</td>
+      <td class="tdc">Weight of the<br> osazones. &nbsp;</td>
+   </tr><tr>
+      <td class="tdl bb" colspan="2">&nbsp;</td>
+      <td class="tdc bb">gram.</td>
+   </tr><tr>
+      <td class="tdl bb" rowspan="2">1</td>
+      <td class="tdl_ws1">Saccharose, ordinary</td>
+      <td class="tdc">0.71</td>
+   </tr><tr>
+      <td class="tdl_ws1 bb">Glucose and levulose (.526 g each)</td>
+      <td class="tdc bb">0.73</td>
+   </tr><tr>
+      <td class="tdl bb" rowspan="2">2</td>
+      <td class="tdl_ws1">Maltose</td>
+      <td class="tdc">0.55</td>
+   </tr><tr>
+      <td class="tdl_ws1 bb">Glucose (1.052 g)</td>
+      <td class="tdc bb">0.58</td>
+   </tr><tr>
+      <td class="tdl bb" rowspan="2">3</td>
+      <td class="tdl_ws1">Raffinose, crystallized</td>
+      <td class="tdc">0.48</td>
+   </tr><tr>
+      <td class="tdl_ws1 bb">Levulose, glucose and galactose (.333 g each)</td>
+      <td class="tdc bb">0.53</td>
+   </tr><tr>
+      <td class="tdl bb" rowspan="2">4</td>
+      <td class="tdl_ws1">Lactose, crystallized</td>
+      <td class="tdc">0.38</td>
+   </tr><tr>
+      <td class="tdl_ws1 bb">Glucose and galactose (.500 g each)</td>
+      <td class="tdc bb">0.39</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>It is noticed that the agreement for each saccharose is as satisfactory
+<span class="pagenum"><a id="Page_175"></a>[Pg 175]</span>
+as possible. Numbers obtained with the products of inversion are always
+a little low by reason of the destructive action of sulfuric acid,
+and in particular, upon levulose. This is, moreover, quite sensible
+when the product has to be heated for a long time with sulfuric acid
+in order to secure a complete inversion. It is evident from the
+data cited from the papers of Fischer, Maquenne, and others, that
+the determination of sugars by this method is not a very difficult
+analytical process and may, in the near future, become of great
+practical importance.</p>
+
+<p><b>148. Molecular Weights of Carbohydrates.</b>—In the examination of
+carbohydrates the determination of the molecular weights is often of
+the highest analytical value.</p>
+
+<p>The uncertainty in respect of the true molecular weights of the
+carbohydrates is gradually disappearing by reason of the insight into
+the composition of these bodies, which recently discovered physical
+relations have permitted.</p>
+
+<p>Raoult, many years ago,<a id="FNanchor_116" href="#Footnote_116" class="fnanchor">[116]</a>
+proposed a method of determining molecular weights which is
+particularly applicable to carbohydrates soluble in water.</p>
+
+<p>The principle of Raoult’s discovery may be stated as follows: The
+depression of the freezing point of a liquid, caused by the presence of
+a dissolved liquid or solid, is proportionate to the absolute amount of
+substance dissolved and inversely proportionate to its molecular weight.</p>
+
+<p>The following formulas may be used in computing results:</p>
+
+<div class="blockquot">
+<p><i>C</i> = observed depression of freezing point:</p>
+
+<p><i>P</i> = weight of anhydrous substance in 100 grams:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl bb">&nbsp;<i>C</i>&nbsp;</td>
+      <td class="tdl" rowspan="2">= <i>A</i> = depression produced by one gram substance in 100 grams:</td>
+   </tr><tr>
+      <td class="tdc"><i>P</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p><i>K</i> = depression produced by dissolving in 100 cubic centimeters
+a number of grams of the substance corresponding to its
+molecular weight:</p>
+
+<p><i>M</i> = molecular weight:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">Then we have, <i>K</i> =&nbsp;</td>
+      <td class="tdc bb"><i>C</i></td>
+      <td class="tdl" rowspan="2">&nbsp;× <i>M</i>.</td>
+   </tr><tr>
+      <td class="tdc"><i>P</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p><i>K</i> is a quantity varying with the nature of the solvent but with
+the same solvent remaining sensibly constant for numerous groups of compounds.
+<span class="pagenum"><a id="Page_176"></a>[Pg 176]</span></p>
+
+<p>The value of</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">A&nbsp;<span class="fs_200">(</span>&nbsp;</td>
+      <td class="tdc bb"><i>C</i></td>
+      <td class="tdl" rowspan="2">&nbsp;<span class="fs_200">)</span></td>
+   </tr><tr>
+      <td class="tdc"><i>P</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="no-indent">can be determined by experiment. The molecular
+weight can therefore be calculated from the formula</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>M</i> =&nbsp;</td>
+      <td class="tdc bb"><i>K</i></td>
+   </tr><tr>
+      <td class="tdc"><i>A</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="spb1">With organic compounds in water the value of <i>K</i>
+is almost constant.</p>
+</div>
+
+<p>Brown and Morris<a id="FNanchor_117" href="#Footnote_117" class="fnanchor">[117]</a>
+report results of their work in extending Raoult’s investigations of
+the molecular weight of the carbohydrates. The process is carried on as
+follows:</p>
+
+<p>A solution of the carbohydrate is prepared containing a known weight
+of the substance in 100 cubic centimeters of water. About 120 cubic
+centimeters of the solution are introduced into a thin beaker of about
+400 capacity. This beaker is closed with a stopper with three holes.
+Through one of these a glass rod for stirring the solution is inserted.
+The second perforation carries a delicate thermometer graduated to
+0°.05. The temperature is read with a telescope. The beaker is placed
+in a mixture of ice and brine at a temperature from 2° to 3° below
+the freezing point of the solution. The solution is cooled until its
+temperature is from 0°.5 to 1° below the point of congelation. Through
+the third aperture in the stopper a small lump of ice taken from a
+frozen portion of the same solution, is dropped, causing at once the
+freezing process to begin. The liquid is briskly stirred and as the
+congelation goes on the temperature rises and finally becomes constant.
+The reading is then taken. The depression in the freezing point,
+controlled by the strength of the solution, should never be more than
+from 1° to 2°.</p>
+
+<p>The molecular weights may also be determined by the boiling points of
+their solutions as indicated by the author,<a id="FNanchor_118" href="#Footnote_118" class="fnanchor">[118]</a>
+Beckmann,<a id="FNanchor_119" href="#Footnote_119" class="fnanchor">[119]</a>
+Hite, Orndorff and Cameron.<a id="FNanchor_120" href="#Footnote_120" class="fnanchor">[120]</a></p>
+
+<p>The method applied to some of the more important carbohydrates gave the
+following results:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdc smcap" colspan="2"><b>Dextrose.</b></td>
+   </tr><tr>
+      <td class="tdl">Calculated for C₆H₁₂O₆.</td>
+      <td class="tdc">Found.</td>
+   </tr><tr>
+      <td class="tdc"><i>M</i> = 180</td>
+      <td class="tdr"><i>M</i> = 180.2</td>
+   </tr><tr>
+      <td class="tdc smcap" colspan="2">&nbsp;<br><b>Sucrose.</b></td>
+   </tr><tr>
+      <td class="tdl">Calculated for C₁₂H₂₂O₁₁.</td>
+      <td class="tdc">Found.</td>
+   </tr><tr>
+      <td class="tdc"><i>M</i> = 342</td>
+      <td class="tdr"><i>M</i> = 337.5
+                    <span class="pagenum"><a id="Page_177"></a>[Pg 177]</span></td>
+   </tr><tr>
+      <td class="tdc smcap" colspan="2">&nbsp;<br><b>Invertose (Dextrose and Levulose).</b></td>
+   </tr><tr>
+      <td class="tdl">Calculated for C₆H₁₂O₆</td>
+      <td class="tdc">Found.</td>
+   </tr><tr>
+      <td class="tdc"><i>M</i> = 180</td>
+      <td class="tdr"><i>M</i> = 174.3</td>
+   </tr><tr>
+      <td class="tdc smcap" colspan="2">&nbsp;<br><b>Maltose.</b></td>
+   </tr><tr>
+      <td class="tdl">Calculated for C₁₂H₂₂O₁₁.</td>
+      <td class="tdc">Found.</td>
+   </tr><tr>
+      <td class="tdc"><i>M</i> = 342</td>
+      <td class="tdr"><i>M</i> = 322</td>
+   </tr><tr>
+      <td class="tdc smcap" colspan="2">&nbsp;<br><b>Lactose.</b></td>
+   </tr><tr>
+      <td class="tdl">Calculated for C₁₂H₂₂O₁₁.</td>
+      <td class="tdc">Found.</td>
+   </tr><tr>
+      <td class="tdc"><i>M</i> = 342</td>
+      <td class="tdr"><i>M</i> = 345</td>
+   </tr><tr>
+      <td class="tdc smcap" colspan="2">&nbsp;<br><b>Arabinose.</b></td>
+   </tr><tr>
+      <td class="tdl">Calculated for C₅H₁₀O₅.</td>
+      <td class="tdc">Found.</td>
+   </tr><tr>
+      <td class="tdc"><i>M</i> = 150</td>
+      <td class="tdr"><i>M</i> = 150.3</td>
+   </tr><tr>
+      <td class="tdc smcap" colspan="2">&nbsp;<br><b>Raffinose.</b></td>
+   </tr><tr>
+      <td class="tdl">Calculated for C₁₈H₃₂O₁₆.5H₂O.</td>
+      <td class="tdc">Found.</td>
+   </tr><tr>
+      <td class="tdc"><i>M</i> = 594</td>
+      <td class="tdr"><i>M</i> = 528</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>149. Birotation.</b>—As is well known, dextrose exhibits in fresh
+solutions the phenomenon of birotation. The authors supposed that
+this phenomenon might have some relation to the size of the molecule.
+They, therefore, determined the molecular volume of freshly dissolved
+dextrose by the method of Raoult and found <i>M</i> = 180. The high
+rotatory power of recently dissolved dextrose is therefore not due to
+any variation in the size of its molecule.</p>
+
+<p>The mathematical theory of birotation is given by Müller as
+follows.<a id="FNanchor_121" href="#Footnote_121" class="fnanchor">[121]</a>
+In proportion as the unstable modification <i>A</i> is
+transformed into the stable modification <i>B</i>, the rotation will
+vary. Let ρ = the specific rotatory power of <i>B</i> and <i>a</i>ρ =
+that of <i>A</i>, both in the anhydrous state. Let now <i>p</i> grams
+of the substance be dissolved in <i>V</i> cubic centimeters of solvent
+and observed in a tube <i>l</i> decimeters in length. The time from
+making the solution is represented by θ. The angle of rotation α is
+read at the time θ. Let <i>x</i> = the mass of <i>A</i>, and <i>y</i> =
+that of <i>B</i>, and the equation is derived.</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">α =&nbsp;</td>
+      <td class="tdc bb"><i>a ρ xl</i></td>
+      <td class="tdl" rowspan="2">&nbsp; + &nbsp;</td>
+      <td class="tdc bb">ρ<i>yl</i></td>
+   </tr><tr>
+      <td class="tdc"><i>V</i></td>
+      <td class="tdc"><i>V</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="center fs_105">But&emsp;<i>x</i> + <i>y</i> = <i>p</i></p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"> whence&emsp;α =
+         <span class="fs_150">[</span>(<i>a</i> - 1)<i>x</i> + <i>p</i><span class="fs_150">]</span></td>
+      <td class="tdc bb">ρ<i>l</i></td>
+   </tr><tr>
+      <td class="tdc"><i>V</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p>If now there be introduced into the calculation the final angle
+of rotation α<sub>n</sub>, which can be determined with great exactness;
+we have</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">α<sub>n</sub> = &nbsp;</td>
+      <td class="tdc bb"><i>p ρ l</i></td>
+   </tr><tr>
+      <td class="tdc"><i>V</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">and consequently α = α<sub>n</sub><span class="fs_200">[</span>1 +</td>
+      <td class="tdc bb">(<i>a</i> - 1)<i>x</i></td>
+      <td class="tdl" rowspan="2"><span class="fs_200">]</span>.</td>
+   </tr><tr>
+      <td class="tdc"><i>p</i></td>
+   </tr>
+ </tbody>
+</table>
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">whence &nbsp;</td>
+      <td class="tdc bb">(<i>a</i> - 1)<i>x</i></td>
+      <td class="tdl" rowspan="2">&nbsp; = &nbsp;</td>
+      <td class="tdc bb">α</td>
+      <td class="tdl" rowspan="2">&nbsp; - 1.</td>
+   </tr><tr>
+      <td class="tdc"><i>p</i></td>
+      <td class="tdc">α<sub>n</sub></td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_178"></a>[Pg 178]</span>
+This equation gives the quantity <i>x</i> of the unstable matter which
+is transformed into the stable modification in the time θ.</p>
+
+<p>It must be admitted that the quantity <i>dx</i> which is changed
+during the infinitely small time <i>d</i>θ is proportional to the
+mass <i>x</i> which still exists at the moment θ, whence <i>dx</i> =
+-Cʹ<i>xd</i>θ where Cʹ represents a constant positive factor. From this
+is derived the equation</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdc bb"><i>dx</i></td>
+      <td class="tdl" rowspan="2">&nbsp; = &nbsp;- Cʹ<i>d</i>θ.</td>
+   </tr><tr>
+      <td class="tdc"><i>x</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Integrating and calling <i>x</i> the quantity of matter changed to the
+stable form at the moment θ, corresponding to a rotation α₀, we have</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">Cʹ = &nbsp;</td>
+      <td class="tdc bb">1</td>
+      <td class="tdl" rowspan="2">&nbsp; log. nap. &nbsp;</td>
+      <td class="tdc bb"><i>x</i>₀</td>
+      <td class="tdl" rowspan="2">&nbsp;,</td>
+   </tr><tr>
+      <td class="tdc">θ - θ₀</td>
+      <td class="tdc"><i>x</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="no-indent">and taking into consideration the equation given
+above, and substituting common for superior logarithms we get</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">C = &nbsp;</td>
+      <td class="tdc bb">1</td>
+      <td class="tdl" rowspan="2">&nbsp; log. &nbsp;</td>
+      <td class="tdc bb">α₀ - αₙ</td>
+      <td class="tdl" rowspan="2">&nbsp;.</td>
+   </tr><tr>
+      <td class="tdc">θ - θ₀</td>
+      <td class="tdc">α - αₙ</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Experience has shown that such a constant C really exists, and
+its value can be easily calculated from the data of Parcus and
+Tollens.<a id="FNanchor_122" href="#Footnote_122" class="fnanchor">[122]</a>
+The mean value of C from these data is 0.0301 for
+arabinose; 0.0201 for xylose; 0.0393 for rhamnose; 0.0202 for fucose;
+0.00927 for galactose; 0.00405 for lactose; 0.00524 for maltose, and
+for dextrose, 0.00348 at 11° to 13° and 0.00398 from 13° to 15°. The
+constant C as is well known, increases as the temperature is raised.</p>
+
+<p>The constant C, at a given temperature, measures the progress of the
+phenomenon of the change from the unstable to the stable state. It will
+be noticed that among the sugars possessing multirotation properties the
+pentoses possess a much higher speed of transformation than the others.</p>
+
+<p id="P_150"><b>150. Estimation of Pentose Sugars and Pentosans as
+Furfurol.</b>—The production of furfurol by distilling carbohydrates
+with an acid has already been mentioned. Tollens and his associates
+have shown that with pentose sugars, and carbohydrate bodies yielding
+them, the production of furfurol is quantitive.
+<span class="pagenum"><a id="Page_179"></a>[Pg 179]</span></p>
+
+<p>The production and estimation of furfurol have been systematically
+studied by Krug, to whose paper the reader is referred for the complete
+literature of the subject.<a id="FNanchor_123" href="#Footnote_123" class="fnanchor">[123]</a>
+The essential principles of the operation are based on the conversion
+of the pentoses into furfurol by distilling with a strong acid, and the
+subsequent precipitation and estimation of the furfurol formed in the
+first part of the reaction.</p>
+
+<p>The best method of conducting the distillation is as follows:</p>
+
+<p>Five grams of the pentose substance are placed in a flask of about a
+quarter liter capacity, with 100 cubic centimeters of hydrochloric acid
+of 1.06 specific gravity. The arrangement of the apparatus is shown in
+<a href="#FIG_46">Fig. 46</a>. The flame of the lamp is so regulated as
+to secure about two cubic centimeters of distillate per minute.</p>
+
+<div class="center smcap">
+    <img id="FIG_46" src="images/fig46.jpg" alt="" width="600" height="369" >
+    <p class="center spb1">Figure 46. Distilling Apparatus for Pentoses.</p>
+</div>
+
+<p>The distillate is received in a graduated cylinder and as soon
+as thirty cubic centimeters are collected, an equal quantity of
+hydrochloric acid, of the strength noted, is added to the distilling
+flask, allowing it to flow in slowly so as not to stop the ebullition.
+The process is continued until a drop of the distillate gives no
+sensible reaction for furfurol when tested with anilin acetate. The
+test is applied as follows: Place a drop of the distillate on a piece
+<span class="pagenum"><a id="Page_180"></a>[Pg 180]</span>
+of filter paper moistened with anilin acetate. The presence of furfurol
+will be disclosed by the production of a brilliant red color. Usually
+about three hours are consumed in the distillation, during which time a
+little less than 400 cubic centimeters of distillate is obtained. The
+distillate is neutralized with solid sodium carbonate and, in order
+to have always the same quantity of common salt present, 10.2 grams
+of sodium chlorid are added for each fifty cubic centimeters of water
+necessary to make the total volume to half a liter.<a id="FNanchor_124" href="#Footnote_124" class="fnanchor">[124]</a></p>
+
+<p>The reactions with pentosans probably consist in first splitting up of
+the molecule into a pentose and the subsequent conversion of the latter
+into furfurol according to the following equations:</p>
+
+<div class="blockquot">
+<p class="center">&nbsp; (C₅H₈O₄)ₙ &nbsp; + &nbsp; (H₂O)ₙ = (C₅H₁₀O₅)ₙ<br>
+Pentosan.&emsp;&nbsp; Water.<span class="ws2">Pentose.</span></p>
+
+<p>and</p>
+
+<p class="center">(C₅H₁₀O₅)ₙ = (C₅H₄O₂)ₙ + (3H₂O)ₙ.<br>
+Pentose.&emsp;&nbsp;Furfurol.<span class="ws2">Water.</span></p>
+</div>
+
+<p><b>151. Determination of Furfurol.</b>—The quantity of furfurol
+obtained by the process mentioned above may be determined in several ways.</p>
+
+<p><i>As Furfuramid.</i>—When ammonia is added to a saturated solution
+of furfurol, furfuramid, (C₅H₄O)₃N₂, is formed. In order to secure the
+precipitate it is necessary that the furfurol be highly concentrated
+and this can only be accomplished by a tedious fractional distillation.
+This method, therefore, has little practical value.</p>
+
+<p><i>As Furfurolhydrazone.</i>—Furfurol is precipitated almost
+quantitively, even from dilute solutions, by phenylhydrazin. The
+reaction is represented by the equation:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdc">C₆H₈N₂</td>
+      <td class="tdl_wsp">+</td>
+      <td class="tdl_wsp">C₅H₄O₂</td>
+      <td class="tdl_wsp">=</td>
+      <td class="tdc">C₁₁H₁₀N₂O</td>
+      <td class="tdl_wsp">+</td>
+      <td class="tdc">H₂O.</td>
+   </tr><tr>
+      <td class="tdl">Phenylhydrazin.</td>
+      <td class="tdl_wsp">&nbsp;</td>
+      <td class="tdl_wsp">Furfurol.</td>
+      <td class="tdl_wsp">&nbsp;</td>
+      <td class="tdl_wsp">Furfurolhydrazone.</td>
+      <td class="tdl_wsp">&nbsp;</td>
+      <td class="tdl_wsp">Water.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>152. Volumetric Methods.</b>—Tollens and Günther have proposed
+a volumetric method which is carried out as follows:<a id="FNanchor_125" href="#Footnote_125" class="fnanchor">[125]</a>
+The distillation is accomplished in the manner described. The distillate
+is placed in a large beaker, neutralized with sodium carbonate and
+acidified with a few drops of acetic. Phenylhydrazin solution of known
+strength is run in until a drop of the liquid, after thorough mixing,
+<span class="pagenum"><a id="Page_181"></a>[Pg 181]</span>
+shows no reaction for furfurol with anilin acetate. The reagent is
+prepared by dissolving five grams of pure phenylhydrazin and three
+of glacial acetic acid in distilled water, and diluting to 100 cubic
+centimeters. The solution is set by dissolving from two-tenths to
+three-tenths gram of pure furfurol in half a liter of water and
+titrating with the phenylhydrazin as indicated above. The quantity of
+the pentose used has a great influence on the result.</p>
+
+<p>With nearly a gram of arabinose about fifty per cent of furfurol were
+obtained while when nearly five grams were used only about forty-six
+per cent of furfurol were found. With xylose a similar variation was
+found, the percentage of furfurol, decreasing as the quantity of
+pentose increased. The method, therefore, gives only approximately
+accurate results.</p>
+
+<p><b>153. Method of Stone.</b>—Another volumetric method proposed by
+Stone is based on the detection of an excess of phenylhydrazin by its
+reducing action on the fehling reagent.<a id="FNanchor_126" href="#Footnote_126" class="fnanchor">[126]</a>
+A standard solution of phenylhydrazin is prepared by dissolving one
+gram of the hydrochlorate and three grams of sodium acetate in water
+and completing the volume of the liquor to 100 cubic centimeters. This
+solution contains 1.494 milligrams of phenylhydrazin in each cubic
+centimeter, theoretically equivalent to 1.328 milligrams of furfurol.
+The reagent is set by titrating against a known weight of furfurol.
+Pure furfurol may be prepared by treating the crude article with
+sulfuric acid and potassium dichromate, and subjecting the product to
+fractional distillation. The distillate is treated with ammonia and
+the furfuramid formed is purified by recrystallizing from alcohol and
+drying over sulfuric acid. One gram of this furfuramid is dissolved in
+dilute acetic acid and the volume completed to one liter with
+water.<a id="FNanchor_127" href="#Footnote_127" class="fnanchor">[127]</a>
+The phenylhydrazin solution being unstable, is to be prepared at the time of use.</p>
+
+<p>The titration is conducted as follows: Twenty-five cubic centimeters of
+the distillate obtained from a pentose body, by the method described
+above, are diluted with an equal volume of water, a certain quantity
+of the phenylhydrazin solution added to the mixture from a burette and
+the whole heated quickly to boiling. The flask is rapidly cooled and a
+portion of its contents poured on a filter. The filtrate should have a
+<span class="pagenum"><a id="Page_182"></a>[Pg 182]</span>
+pale yellow color and be perfectly clear. If it become turbid on
+standing, it should be refiltered. Two cubic centimeters of the clear
+filtrate are boiled with double the quantity of the fehling reagent.
+If phenylhydrazin be present, the color of the mixture will change
+from blue to green. By repeating the work, with varying quantities of
+phenylhydrazin, a point will soon be reached showing the end of the
+reaction in a manner entirely analogous to that observed in volumetric
+sugar analysis.</p>
+
+<p>In practice the volumetric methods have given place to the more exact
+gravimetric methods described below.</p>
+
+<p id="P_154"><b>154. Gravimetric Methods.</b>—The distillation is carried on and
+the volume of the distillate completed to half a liter as described
+above. Chalmot and Tollens then proceed as follows:<a id="FNanchor_128" href="#Footnote_128" class="fnanchor">[128]</a>
+Ten cubic centimeters of a solution of phenylhydrazin acetate,
+containing in 100 cubic centimeters twelve grams of the phenylhydrazin
+and seven and a half grams of glacial acetic acid dissolved and
+filtered, are added to the distillate and the mixture stirred with an
+appropriate mechanism for half an hour. The furfurolhydrazone at the
+end of this time will have separated as small reddish-brown crystals.
+The mixture is then thrown onto an asbestos filter and the liquid
+separated with suction. The suction should be very gradually applied
+so as not to clog the felt. The precipitate adhering to the beaker
+is washed into the filter with 100 cubic centimeters of water. The
+precipitate is dried at about 60° and weighed. As a check the hydrazone
+may be dissolved in hot alcohol, the filter well washed, dried and
+again weighed. To obtain the weight of furfurol the weight of hydrazone
+found is multiplied by 0.516 and 0.025 added to compensate for the
+amount which was held in solution or removed by washing. Less than one
+per cent of pentose can not be determined by this method since that
+amount is equalled by the known losses during the manipulation.</p>
+
+<p><i>Factor.</i>—To convert the furfurol found into pentoses, the
+following factors are used:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Per cent furfurol<br>obtained from five<br>&nbsp;grams of pentoses.&nbsp;</td>
+      <td class="tdc">Multiply for<br>&nbsp;arabinose by.&nbsp;</td>
+      <td class="tdc">&nbsp;Multiply for&nbsp;<br>xylose by.</td>
+      <td class="tdc">Multiply for<br>&nbsp;penta-glucoses by.</td>
+   </tr><tr>
+      <td class="tdc" colspan="4">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">2.5 per cent or less</td>
+      <td class="tdc">1.90</td>
+      <td class="tdc">1.70</td>
+      <td class="tdc">1.67</td>
+   </tr><tr>
+      <td class="tdl">5.0  &nbsp;”&emsp;”&emsp;”  more</td>
+      <td class="tdc">2.04</td>
+      <td class="tdc">1.90</td>
+      <td class="tdc">1.92</td>
+   </tr>
+ </tbody>
+</table>
+
+<p id="P_155"><span class="pagenum"><a id="Page_183"></a>[Pg 183]</span>
+<b>155. Method Of Krug.</b>—In conducting the determination of
+furfurol, according to the method of Chalmont and Tollens just noticed,
+Krug observed that the filtrate, after standing for some time, yielded
+a second precipitate of furfurol hydrazone. Great difficulty was also
+experienced in collecting the precipitate upon the filter on account
+of the persistency with which it stuck to the sides of the vessel
+in which the precipitation took place.<a id="FNanchor_129" href="#Footnote_129" class="fnanchor">[129]</a>
+In order to avoid these two objections, Krug modified the method as
+described below and this modified method is now exclusively used in
+this laboratory.</p>
+
+<p>After the precipitation of the furfurol hydrazone, it is stirred
+vigorously, by means of an appropriate mechanical stirrer, for at
+least half an hour and then allowed to rest for twenty-four hours. On
+filtering after that length of time the filtrate remains perfectly
+clear and no further precipitation takes place. After the filtration is
+complete and the beaker and filtering tube well washed, no attempt is
+made to detach the part of the filtrate adhering to the beaker but the
+whole of the precipitate, both that upon the filter and that adhering
+to the sides of the beaker, is dissolved in strong alcohol, from thirty
+to forty cubic centimeters being used. The alcoholic solution is
+collected in a small weighed flask, the alcohol evaporated at a gentle
+heat and the last traces of water removed by heating to 60° and blowing
+a current of dry air through the flask. After weighing the precipitate
+of furfurol hydrazone, obtained as above, the calculation of the weight
+of pentose bodies is accomplished by means of the usual factors.</p>
+
+<p><b>156. Precipitation of Furfurol with Pyrogalol.</b>—Furfurol is
+thrown out of solution in combination with certain phenol bodies by
+heating together in an acid solution. Hotter has proposed a method
+for the determination of furfurol based on the above fact.<a id="FNanchor_130" href="#Footnote_130" class="fnanchor">[130]</a>
+The furfurol is obtained by distillation in the manner already described
+and hydrochloric acid is added if necessary to secure twelve per cent
+of that body in a given volume. The furfurol is thrown out of an
+aliquot portion by heating with an excess of pyrogalol in closed tubes
+for about two hours at 110°. The reaction takes place in two stages,
+represented by the following equations:
+<span class="pagenum"><a id="Page_184"></a>[Pg 184]</span></p>
+
+<div class="blockquot">
+<p class="f105">C₅H₄O₂&#160; + C₆H₆O₃ = C₁₁H₁₀O₅<br>and<br>
+2C₁₁H₁₀O₅ = C₂₂H₁₈O₉ + H₂O.</p>
+</div>
+
+<p>The aliquot part of the distillate used should not contain more than
+one-tenth of a gram of furfurol. The precipitate formed in this way is
+collected on an asbestos felt, dried at 103° and weighed. The weight
+obtained divided by 1.974 gives the corresponding amount of furfurol.
+There is some difficulty experienced in loosening the precipitate from
+the sides of the tubes in which the heating takes place, but this
+defect can be overcome by heating in covered beakers in an autoclave.</p>
+
+<p id="P_157"><b>157. Precipitation with Phloroglucin.</b>—Instead of using
+pyrogalol for the precipitating reagent phloroglucin may be employed.
+The method of procedure proposed by Councler for this purpose is given
+below.<a id="FNanchor_131" href="#Footnote_131" class="fnanchor">[131]</a>
+The furfurol is prepared by distillation in the usual way. The volume
+of the distillate obtained is completed to half a liter with twelve per
+cent hydrochloric acid, and an aliquot portion, varying in volume with
+the percentage of furfurol is withdrawn for precipitation. This portion
+is placed in a glass-stoppered flask with about twice the quantity of
+finely powdered phloroglucin necessary to combine with the furfurol
+present. The contents of the flask are well shaken and allowed to stand
+fifteen hours. The precipitate is collected on an asbestos filter, washed
+free of chlorin, dried at the temperature of boiling water and weighed.</p>
+
+<p>The theoretical quantity of precipitate corresponding to one part
+of furfurol, <i>viz.</i>, 2.22 parts, is never obtained since the
+precipitate is not wholly insoluble in water. The actual proportions
+between the precipitate and the original furfurol vary with the amount
+of precipitate obtained.</p>
+
+<p>When the weight of the precipitate is 200 milligrams and over, 2.12
+parts correspond to one part of furfurol. When the weight of the
+precipitate varies from fifty to 100 milligrams, the ratio is as 2.05:1
+and when only about twenty-five milligrams of precipitate are obtained
+the ratio is as 1.98:1.</p>
+
+<p>The quantity of pentose bodies corresponding to the furfurol is
+calculated from the factors given by Tollens in a preceding paragraph.
+<span class="pagenum"><a id="Page_185"></a>[Pg 185]</span></p>
+
+<p>The reaction which takes place with furfurol and phloroglucin is simply
+a condensation of the reagents with the separation of water. It is very
+nearly represented by the following formula:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdc">2C₅H₄O₂</td>
+      <td class="tdl_wsp">+</td>
+      <td class="tdc">C₆H₆O₃</td>
+      <td class="tdl_wsp">=</td>
+      <td class="tdc">C₁₆H₁₂O₆</td>
+      <td class="tdl_wsp">+</td>
+      <td class="tdc">H₂O.</td>
+   </tr><tr>
+      <td class="tdl">Furfurol.</td>
+      <td class="tdl_wsp">&nbsp;</td>
+      <td class="tdl_wsp">Phloroglucin</td>
+      <td class="tdl_wsp">&nbsp;</td>
+      <td class="tdc">Condensation<br>product.</td>
+      <td class="tdl_wsp">&nbsp;</td>
+      <td class="tdl_wsp">Water.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>It has been shown by Welbel and Zeisel,<a id="FNanchor_132" href="#Footnote_132" class="fnanchor">[132]</a>
+that in the presence of twelve per cent of hydrochloric acid
+phloroglucin itself is condensed into dark insoluble compounds. When
+three molecules of furfurol and two molecules of phloroglucin are
+present, the bodies are both condensed and separated by continued
+action. When from one and a quarter to three parts of phloroglucin by
+weight are used to one part of furfurol, the weight of the precipitate
+obtained under constant conditions may serve sufficiently well for
+the calculation of the furfurol. The precipitates contain chlorin,
+which they give up even in the cold, to water. For these reasons the
+analytical data obtained by the method of Councler, given above, are
+apt to be misleading. It is probable also that similar conditions
+may to a certain extent prevail in the separation of furfurol with
+phenylhydrazin, and further investigation in this direction is
+desirable. For the present the very best method that can be recommended
+for the estimation of pentoses and pentosans is the conversion thereof
+into furfurol and the separation of the compound with phenylhydrazin
+acetate.</p>
+
+<p><b>158. Estimation of Sugars by Fermentation.</b>—When a solution
+of a hexose sugar is subjected to the action of certain ferments a
+decomposition of the molecule takes place with the production of carbon
+dioxid and various alcohols and organic acids. Under the action of
+the ferment of yeast <i>Saccharomyces cerevisiae</i> the sugar yields
+theoretically only carbon dioxid and ethyl alcohol, as represented by
+the equation:</p>
+
+<p class="f105">C₆H₁₂O₆ = 2C₂H₆O + 2CO₂.</p>
+
+<p>The theoretical quantities of alcohol and carbon dioxid obtained
+according to this equation are 51.11 percent of alcohol and 48.89 per
+cent of carbon dioxid.</p>
+
+<p>When the yeast ferment acts on cane sugar the latter first suffers
+inversion, and the molecules of dextrose and levulose produced are
+<span class="pagenum"><a id="Page_186"></a>[Pg 186]</span>
+subsequently converted into alcohol and carbon dioxid as represented
+below:</p>
+
+<p class="f105">C₁₂H₂₂O₁₁ + H₂O = 2C₆H₁₂O₆<br>
+2C₆H₁₂O₆ = 4C₂H₆O + 4CO₂.</p>
+
+<p>Cane sugar, plus the water of hydrolysis, will yield theoretically 53.8
+per cent of alcohol and 51.5 per cent of carbon dioxid.</p>
+
+<p>In practice the theoretical proportions of alcohol and carbon dioxid
+are not obtained because of the difficulty of excluding other
+fermentative action, resulting in the formation especially of succinic
+acid and glycerol. Moreover, a part of the sugar is consumed by the
+yeast cells to secure their proper growth and development. In all
+only about ninety-five per cent of the sugar can be safely assumed as
+entering into the production of alcohol. About 48.5 per cent of alcohol
+are all that may be expected of the weight of dextrose or invert sugar
+used. Only sugars containing three molecules of carbon or some multiple
+thereof are fermentable. Thus the trioses, hexoses, nonoses, etc., are
+susceptible of fermentation, while the tetroses, pentoses, etc., are
+not.</p>
+
+<p><b>159. Estimating Alcohol.</b>—In the determination of sugar by
+fermentation, a rather dilute solution not exceeding ten per cent
+should be used. A quantity of pure yeast, equivalent to four or five
+per cent of the sugar used, is added, and the contents of the vessel,
+after being well shaken, exposed to a temperature of from 25° to 30°
+until the fermentation has ceased, which will be usually in from
+twenty-four to thirty-six hours. The alcohol is then determined in the
+residue by the methods given hereafter.</p>
+
+<p>The weight of the alcohol obtained multiplied by 100 and divided by
+48.5, will give the weight of the hexose reducing sugar which has been
+fermented. Ninety-five parts of sucrose will give 100 parts of invert
+sugar.</p>
+
+<p><i>Example.</i>—Let the weight of alcohol obtained be 0.625 gram. Then
+0.625 × 100 ÷ 48.5 = 1.289 grams, the weight of the hexose, which has
+been fermented; 1.289 grams of dextrose or levulose correspond to 1.225
+of sucrose.</p>
+
+<p><b>160. Estimating Carbon Dioxid.</b>—The sugar may also be determined
+by estimating the amount of carbon dioxid produced during the
+<span class="pagenum"><a id="Page_187"></a>[Pg 187]</span>
+fermentation. For this purpose the mixture of sugar solution and yeast,
+prepared as above mentioned, is placed in a flask whose stopper carries
+two tubes, one of which introduces air free of carbon dioxid into the
+contents of the flask, and the other conducts the evolved carbon dioxid
+into the absorption bulbs. In passing to the absorption bulbs the
+carbon dioxid is freed of moisture by passing through another set of
+bulbs filled with strong sulfuric acid. During the fermentation, the
+carbon dioxid is forced through the bulbs by the pressure produced, or
+better, a slow current of air is aspirated through the whole apparatus.
+The aspiration is continued after the fermentation, has ceased, until
+all the carbon dioxid is expelled. Towards the end, the contents of
+the flask may be heated to near the boiling-point. The increase of
+the weight of the potash bulbs will give the weight of carbon dioxid
+obtained. A hexose reducing sugar will yield about 46.5 per cent of its
+weight of carbon dioxid. The calculation is made as suggested for the
+alcohol process.</p>
+
+<p>The fermentation process has little practical value save in determining
+sucrose in presence of lactose, as will be described in another place.</p>
+
+<p><b>161. Precipitation of Sugars in Combination with the Earthy
+Bases.</b>—The sugars combine in varying proportions with the oxids
+and hydroxids of calcium, strontium and barium. Sucrose especially,
+furnishes definite crystalline aggregates with these bases in such
+a way as to form the groundwork of several technical processes in
+the separation of that substance from its normally and abnormally
+associated compounds. These processes have little use as analytical
+methods, but are of great value, as mentioned, from a technical point
+of view.</p>
+
+<p><b>162. Barium Saccharate.</b>—This compound is formed by mixing
+the aqueous solutions of barium hydroxid and sugar. The saccharate
+separates in bright crystalline plates or needles from the warm
+solution, as <b>C₁₂H₂₂O₁₁BaO</b>. One part of this precipitate is soluble in
+about forty-five parts of water, both at 15° and 100°.</p>
+
+<p><b>163. Strontium Saccharates.</b>—Both the mono- and distrontium
+saccharates are known, <i>viz.</i>, <b>C₁₂H₂₂O₁₁SrO + 5H₂O</b> and
+<b>C₁₂H₂₂O₁₁2SrO</b>.</p>
+
+<p><span class="pagenum"><a id="Page_188"></a>[Pg 188]</span>
+The monosalt may be easily secured by adding a few of its crystals to a
+mixture of sugar and strontium hydroxid solutions.</p>
+
+<p>The disaccharate is precipitated as a granular substance when from two
+to three molecules of strontium hydroxid are added to a boiling sugar
+solution. The reaction is extensively used in separating the sugar from
+beet molasses.</p>
+
+<p><b>164. Calcium Saccharates.</b>—Three calcium saccharates are known
+in which one molecule of sugar is combined with one, two and three
+molecules of lime respectively.</p>
+
+<p>The monosaccharate is obtained by mixing the sugar and lime in the
+proper proportion and precipitating by adding alcohol.</p>
+
+<p>The precipitate is partly granular and partly jelly-like, and is
+soluble in cold water. The dicalcium compound is obtained in the same
+way and has similar properties. Both, on boiling, with water, form the
+trisaccharate and free sugar.</p>
+
+<p>The tricalcium saccharate is the most important of these compounds, and
+may be obtained directly by mixing freshly burned and finely ground
+lime <b>(CaO)</b> with a very cold dilute solution of sugar.</p>
+
+<p>The compound crystallizes with three or four molecules of water.
+When precipitated as described above, however, it has a granular,
+nearly amorphous structure, and the process is frequently used in the
+separation of sugar from beet molasses.</p>
+
+<p>In the laboratory but little success has been had in using even the
+barium hydroxid as a chemical reagent, and therefore the reactions
+mentioned above are of little value for analytical purposes. In
+separating sugar from vegetable fibers and seeds, however, the
+treatment with strontium hydroxid is especially valuable the sugar
+being subsequently recovered in a free state by breaking up the
+saccharate with carbon dioxid. The technical use of these reactions
+also is of great importance in the beet sugar industry.</p>
+
+<p><b>165. Qualitive Tests for the Different Sugars.</b>—The analyst will
+often be aided in examining an unknown substance by the application
+of qualitive tests, which will disclose to him the nature of the
+saccharine bodies with which he has to deal.</p>
+
+<p><b>166. Optical Test for Sucrose.</b>—The simplest test for the
+presence of sucrose is made with the polariscope. A small quantity of
+<span class="pagenum"><a id="Page_189"></a>[Pg 189]</span>
+the sample under examination is dissolved in water, clarified by any of
+the usual methods, best with alumina cream, and polarized. A portion of
+the liquor is diluted with one-tenth its volume of strong hydrochloric
+acid and heated to just 68°, consuming about fifteen minutes time in
+the operation. The mixture is quickly cooled and again polarized in
+a tube one-tenth longer than before used; or the same tube may be
+used and the observed reading of the scale increased by one-tenth.
+If sucrose be present the second reading will be much lower than the
+first, or may even be to the left.</p>
+
+<p><b>167. Cobaltous Nitrate Test for Sucrose.</b>—Sucrose in solution
+may be distinguished from other sugars by the amethyst violet color
+which it imparts to a solution of cobaltous nitrate. This reaction was
+first described by Reich, in 1856, but has only lately been worked out
+in detail. The test is applied as follows:</p>
+
+<p>To about fifteen cubic centimeters of the sugar solution add five cubic
+centimeters of a five per cent solution of cobaltous nitrate. After
+thoroughly mixing the two solutions, add two cubic centimeters of a
+fifty per cent solution of sodium hydroxid. Pure sucrose gives by this
+treatment an amethyst violet color, which is permanent. Pure dextrose
+gives a turquoise blue color which soon passes into a light green. When
+the two sugars are mixed the coloration produced by the sucrose is the
+predominant one, and one part of sucrose in nine parts of dextrose can
+be distinguished. If the sucrose be mixed with impurities such as gum
+arabic or dextrin, they should be precipitated by alcohol or basic lead
+acetate, before the application of the test. Dextrin may be thrown
+out by treatment of the solution with barium hydroxid and ammoniacal
+lead acetate. The reaction may also be applied to the detection of
+cane sugar in wines, after they are thoroughly decolorized by means of
+lead acetate and bone-black. The presence of added sucrose to milk,
+either in the fresh or condensed state, may also be detected after the
+disturbing matters are thrown out with lead acetate. The presence of
+sucrose in honey may also be detected by this process. The reaction
+has been tried in this laboratory with very satisfactory results. The
+amethyst violet coloration with sucrose is practically permanent. On
+<span class="pagenum"><a id="Page_190"></a>[Pg 190]</span>
+boiling the color is made slightly bluish, but is restored to the
+original tint on cooling. Dextrose gives at first a fine blue color
+which in the course of two hours passes into a pale green. A slight
+flocculent precipitate is noticed in the tube containing the dextrose.
+Maltose and lactose act very much as dextrose, but in the end do not
+give so fine a green color. If the solutions containing dextrose,
+lactose and maltose be boiled, the original color is destroyed and a
+yellow-green color takes its place. The reaction is one which promises
+to be of considerable practical value to analysts, as it may be applied
+for the qualitive detection of sucrose in seeds and other vegetable
+products.<a id="FNanchor_133" href="#Footnote_133" class="fnanchor">[133]</a></p>
+
+<p><b>168. The Dextrose Group.</b>—In case the carbohydrate in question
+shows a right-handed rotation and the absence of sucrose is established
+by the polariscopic observation described above, the presence of the
+dextrose group may be determined by the following
+test.<a id="FNanchor_134" href="#Footnote_134" class="fnanchor">[134]</a></p>
+
+<p>Five grams of the carbohydrate are oxidized by boiling with from twenty
+to thirty cubic centimeters of nitric acid of 1.15 specific gravity,
+and then at gentle heat evaporated to dryness with stirring. If much
+mucic acid be present, as will be the case if the original matter
+contained lactose some water is added and the mixture well stirred,
+and again evaporated to dryness to expel all nitric acid. The residue
+should be of a brown color. The mass is again mixed with a little
+water and the acid reaction neutralized by rubbing with fine-ground
+potassium carbonate. The carbonate should be added in slight excess and
+acetic acid added to the alkaline mixture, which is concentrated by
+evaporation and allowed to stand a few days. At the end of this time
+potassium saccharate has formed and is separated from the mother liquid
+by pouring on a porous porcelain plate. The residue is collected,
+dissolved in a little water and again allowed to crystallize, when it
+is collected on a porous plate, as before, and washed by means of an
+atomizer with a little aqueous spray until it is pure white and free of
+any oxalic acid. The residual acid potassium saccharate may be weighed
+after drying and then converted into the silver salt. The potash salt
+for this purpose is dissolved in water, neutralized with ammonia and
+precipitated with a solution of silver nitrate. The precipitate is well
+<span class="pagenum"><a id="Page_191"></a>[Pg 191]</span>
+stirred, collected on a gooch and washed and dried in a dark place.
+It contains 50.94 percent of silver. All sugars which contain the
+dextrose group yield silver saccharate when treated as above described.
+Inulin, sorbose, arabinose and galactose yield no saccharic acid under
+this treatment, and thus it is shown that they contain no dextrose
+group. Milk sugar, maltose, the dextrins, raffinose and sucrose yield
+saccharic acid when treated as above and therefore all contain the
+dextrose group.</p>
+
+<p><b>169. Levulose.</b>—The levulose group of sugars, wherever it
+occurs, when oxidized with nitric acid, gives rise to tartaric,
+racemic, glycolic and oxalic acids, which are not characteristic,
+being produced also by the oxidation of other carbohydrates. A more
+distinguishing test is afforded by the color reactions produced with
+resorcin.<a id="FNanchor_135" href="#Footnote_135" class="fnanchor">[135]</a>
+The reagent is prepared by dissolving half a gram of resorcin in thirty
+cubic centimeters each of water and strong hydrochloric acid. To the
+sugar solution under examination an equal volume of strong hydrochloric
+acid is added, and then a few drops of the reagent. The mixture is
+gently warmed, and in the presence of levulose develops a fire-red
+color. Dextrose, lactose, mannose and the pentoses do not give the
+coloration, but it is produced by sorbose in a striking degree, and
+also by sucrose and raffinose since these sugars contain the levulose
+group.</p>
+
+<p><b>170. Galactose.</b>—The galactose which arises from the hydrolysis
+of milk sugar is readily recognized by the mucic acid which it gives
+on oxidation with nitric acid.<a id="FNanchor_136" href="#Footnote_136" class="fnanchor">[136]</a>
+The analytical work is conducted as follows: The body containing
+galactose or galactan is placed in a beaker with about sixty cubic
+centimeters of nitric acid of 1.15 specific gravity for each five grams
+of the sample used. The beaker is placed on a steam-bath and heated,
+with frequent stirring, until two-thirds of the nitric acid have been
+evaporated. The residual mixture is allowed to stand over night and
+the following morning is treated with ten cubic centimeters of water,
+allowed to stand for twenty-four hours, filtered through a gooch, and
+the collected matter washed with twenty-five cubic centimeters of
+water, dried at 100° and weighed. The mucic acid collected in this way
+<span class="pagenum"><a id="Page_192"></a>[Pg 192]</span>
+will amount to about thirty-seven per cent of the milk sugar or
+seventy-five per cent of the galactose oxidized. Raffinose yields under
+similar treatment, about twenty-three per cent of mucic acid, which
+proves that the galactose group is contained in that sugar. Raffinose,
+therefore, is composed of one molecule each of dextrose, levulose, and
+galactose.</p>
+
+<p id="P_171"><b>171. Invert Sugar.</b>—The presence of a trace of invert sugar
+accompanying sucrose can be determined by Soldaini’s solution,
+paragraph <b><a href="#P_124">124</a></b>, or by boiling with methyl blue.<a id="FNanchor_137" href="#Footnote_137" class="fnanchor">[137]</a>
+Methyl blue is the hydrochlorate of an ammonium base, which, under the influence
+of a reducing agent, loses two atoms of hydrogen and becomes a colorless
+compound. The test for invert sugar is made as follows: The reagent
+is prepared by dissolving one gram of methyl blue in water. If the
+sugar solution is not clear, twenty grams of the sugar are dissolved
+in water clarified by lead subacetate, the volume completed to 100
+cubic centimeters, and the solid matters separated by filtration. The
+filtrate is made slightly alkaline with sodium carbonate to remove the
+lead. A few drops of soda lye solution are then added and the mixture
+thrown on a filter. To twenty-five cubic centimeters of the filtrate a
+drop of the methyl blue solution is added, and a portion of the liquor
+heated in a test tube over the naked flame. If, after boiling for one
+minute, the coloration disappear, the sample contains at least 0.01
+per cent of invert sugar; if the solution remain blue it contains none
+at all or less than 0.01 per cent. The test may also be made with the
+dilute copper carbonate solution of Ost described further on.</p>
+
+<p id="P_172"><b>172. Compounds with Phenylhydrazin.</b>—Many sugars may also be
+qualitively distinguished by the character of their compounds with
+phenylhydrazin. In general, it may be said that those sugars which
+reduce fehling solution form definite crystalline compounds with the
+reagent named. If a moderately dilute hot solution of a reducing sugar
+be brought into contact with phenylhydrazin acetate, a crystalline
+osazone is separated. The reaction takes place between one molecule of
+the sugar and two molecules of the hydrazin compound, according to the
+following formula:</p>
+
+<p class="f105">C₆H₁₂O₆ + 2C₆H₅N₂H₃ = C₁₈H₂₂N₄O₄ + 2H₂O + H₂.</p>
+
+<p><span class="pagenum"><a id="Page_193"></a>[Pg 193]</span>
+The hydrogen does not escape but combines in the nascent state with the
+excess of phenylhydrazin to form anilin and ammonia.</p>
+
+<p>The precipitation is accomplished as follows:</p>
+
+<p>One part by weight of the sugar, two parts of phenylhydrazin
+hydrochlorate, and three parts of sodium acetate are dissolved in
+twenty parts of water and gradually heated on the water-bath.</p>
+
+<p>The osazone slowly separates in a crystalline form and it is freed from
+the mother liquor by filtration, and purified by solution in alcohol
+and recrystallization. The crystals are composed of yellow needles,
+which are difficultly soluble in water and more easily in hot alcohol.
+The crystals are not decomposed by a dilute acid but are destroyed by
+the action of strong acids.</p>
+
+<p><i>Dextrosazone.</i>—The crystals melt at from 204° to 205°, reduce
+fehling liquor, and dissolved in glacial acetic acid are slightly left
+rotating.</p>
+
+<p><i>Levulosazone.</i>—This body has the same properties as the dextrose
+compound.</p>
+
+<p><i>Maltosazone.</i>—This substance melts at 206° with decomposition.
+It is left rotating. Its structure is represented by the formula
+<b>C₂₄H₃₂N₄O₉</b>.</p>
+
+<p><i>Galactosazone.</i>—This substance, <b>C₁₈H₂₂N₄O₄</b>, has the same
+centesimal composition as the corresponding bodies produced from
+dextrose and levulose. It is distinguished from these compounds,
+however, by its low melting point, <i>viz.</i>, 193°.</p>
+
+<p>The above comprise all the phenylosazones which are important from
+the present point of view. Sucrose, by inversion, furnishes a mixture
+of dextros- and levulosazones when treated with phenylhydrazin, while
+starch and dextrin yield the dextros- or maltosazone when hydrolyzed.
+Lactose yields a mixture of dextros- and galactosazones when hydrolyzed
+and treated as above described.</p>
+
+<p>The reactions with phenylhydrazin are approximately quantitive and it
+is possible that methods of exact determination may be based on them in
+the near future.<a id="FNanchor_138" href="#Footnote_138" class="fnanchor">[138]</a></p>
+
+<p><b>173. Other Qualitive Tests for Sugars.</b>—The analyst may
+sometimes desire a more extended test of qualitive reactions than those
+<span class="pagenum"><a id="Page_194"></a>[Pg 194]</span>
+given above. The changes of color noticed on heating with alkalies may
+often be of advantage in discriminating between different sugars. The
+formation of definite compounds with the earthy and other mineral bases
+may also be used for qualitive determinations. One of the most delicate
+qualitive tests is found in the production of furfurol and this will be
+described in the following paragraphs.</p>
+
+<p><b>174. Detection of Sugars and Other Carbohydrates by Means of
+Furfurol.</b>—The production of furfurol (furfuraldehyd) as noted in
+paragraph <b><a href="#P_150">150</a></b>, is also used quantitively for the determination
+of pentose sugars and pentosans.</p>
+
+<p>Furfurol was first obtained from bran (<i>furfur</i>), whence its name,
+by treating this substance with sulfuric acid, diluted with three
+volumes of water, and subjecting the mixture to distillation. Its
+percentage composition is represented by the symbol <b>C₅H₄O₂</b>, and its
+characteristics as an aldehyd by the molecular structure <b>C₄H₃O,C-HO</b>.</p>
+
+<p>Carbohydrates in general, when treated as described above for bran,
+yield furfurol, but only in a moderate quantity, with the exception of
+the pentoses.</p>
+
+<p>Mylius has shown<a id="FNanchor_139" href="#Footnote_139" class="fnanchor">[139]</a>
+that Pettenkofer’s reaction for choleic acid is due to the furfurol
+arising from the cane sugar employed, which, with the gall acid,
+produces the beautiful red-blue colors characteristic of the
+reaction.</p>
+
+<p>Von Udránszky<a id="FNanchor_140" href="#Footnote_140" class="fnanchor">[140]</a>
+describes methods for detecting traces of carbohydrates by the
+furfurol reaction, which admit of extreme delicacy. The solution of
+furfurol in water, at first proposed by Mylius, is to be used and
+it should not contain more than two and two-tenths per cent, while
+a solution containing five-tenths per cent furfurol is found to be
+most convenient. The furfurol, before using, should be purified by
+distillation, and, as a rule, only a single drop of the solution used
+for the color reaction.</p>
+
+<p>The furfurol reaction proposed by Schiff<a id="FNanchor_141" href="#Footnote_141" class="fnanchor">[141]</a>
+appears to be well suited for the detection of carbohydrates.
+It is made as follows:</p>
+
+<p>Xylidin is mixed with an equal volume of glacial acetic acid and the
+solution treated with some alcohol. Strips of filter paper are then
+dipped in the solution and dried. When these strips of prepared paper
+are brought in contact with the most minute portion of furfurol,
+<span class="pagenum"><a id="Page_195"></a>[Pg 195]</span>
+furoxylidin is formed, <b>C₄H₃OCH(C₈H₈NH₂)₂</b>, producing a beautiful red
+color. In practice, a small portion of the substance, supposed to
+contain a carbohydrate, is placed in a test tube and heated with a
+slight excess of concentrated sulfuric acid. The prepared paper is then
+placed over the mouth of the test tube so as to be brought into contact
+with the escaping vapors of furfurol.</p>
+
+<p>The furfurol reaction with α-naphthol for some purposes, especially
+the detection of sugar in urine, is more delicate than the one just
+described. This reaction was first described by Molisch<a id="FNanchor_142" href="#Footnote_142" class="fnanchor">[142]</a>,
+who, however, did not understand its real nature.</p>
+
+<p>The process is carried on as follows: The dilute solution should
+contain not to exceed from 0.05 to one-tenth per cent of carbohydrates.
+If stronger, it should be diluted. Place one drop of the liquid in a
+test tube with two drops of fifteen per cent alcoholic solution of
+α-naphthol, add carefully one-half cubic centimeter of concentrated
+sulfuric acid, allowing it to flow under the mixture. The appearance
+of a violet ring over a greenish fringe indicates the presence of a
+carbohydrate. If the substance under examination contain more than a
+trace of nitrogenous matter, this must be removed before the tests
+above described are applied.</p>
+
+<p>If the liquids be mixed by shaking when the violet ring is seen, a
+carmine tint with a trace of blue is produced. If this be examined with
+a spectroscope, a small absorption band will be found between D and E,
+and from F outward the whole spectrum will be observed. One drop of
+dextrose solution containing 0.05 per cent of sugar gives a distinct
+reaction by this process. It can be used, therefore, to detect the
+presence of as little as 0.028 milligram of grape sugar. This test has
+been found exceedingly delicate in this laboratory, and sufficiently
+satisfactory without the spectroscopic adjunct.</p>
+
+<p>The furfurol reaction is useful in detecting the presence of minute
+traces of carbohydrates but is of little value in discriminating
+between the different classes of these bodies.</p>
+
+<p>It is not practical here to go into greater detail in the description
+of qualitive reactions. The analyst, desiring further information,
+should consult the standard works on sugar chemistry.
+<a id="FNanchor_143" href="#Footnote_143" class="fnanchor">[143]</a></p>
+
+<p><span class="pagenum"><a id="Page_196"></a>[Pg 196]</span>
+<b>175. Detection of Sugars by Bacterial Action.</b>—Many forms of
+bacteria manifest a selective action towards sugars and this property
+may in the future become the basis of a qualitive and even quantitive
+test for sugars and other carbohydrates. Our present knowledge of the
+subject is due almost exclusively to the researches of Smith, conducted
+at the Department of Agriculture.<a id="FNanchor_144" href="#Footnote_144" class="fnanchor">[144]</a>
+Dextrose is the sugar first and most vigorously attacked by bacterial
+action, and by proper precautions the whole of the dextrose may be
+removed from mixtures with sucrose and lactose.</p>
+
+<p>The development of other forms of micro-organisms which will have the
+faculty of attacking other and special forms of carbohydrates is to be
+looked for with confident assurance of success.</p>
+
+<h3>DETERMINATION OF STARCH.</h3>
+
+<p><b>176. Constitution of Starch.</b>—The molecule of starch is without
+doubt formed by the condensation of a large number of hexose bodies.
+On account of its great insolubility its molecular weight has not been
+determined with any degree of accuracy. Its formula may be expressed
+either as <b>(C₆H₁₀O₅)ₙ</b> or <b>(C₁₂H₂₀O₁₀)ₙ</b>. It is insoluble in cold water
+and other common solvents and does not pass into solution in any reagent
+without undergoing a change of structure. In hot water it forms a paste
+and when heated under pressure with water it undergoes a partial change
+and becomes soluble. Heated with acids or subjected to the action of
+certain ferments it suffers hydrolysis and is transformed into dextrin,
+maltose and dextrose. In analytical work an attempt is usually made to
+transform the starch entirely into dextrose, the quantity of which is
+then determined by some of the processes already given. All starches
+possess the property of giving an intensely blue color with iodin and
+this reaction serves to detect the most minute quantity of the material.</p>
+
+<p>Starch grains derived from different sources are distinguished by
+differences in size and appearance. In most cases a careful examination
+of the starch particles will reveal their origin.<a id="FNanchor_145" href="#Footnote_145" class="fnanchor">[145]</a>
+The greatest part of the cereal grains is composed of starch, the
+percentage ranging from sixty to eighty. Rice has the greatest
+<span class="pagenum"><a id="Page_197"></a>[Pg 197]</span>
+percentage of starch in its composition of any substance. Certain
+root crops are also rich in starch, such as the potato, artichoke and
+cassava. Starch appears as one of the first products of vegetable
+metabolism, according to some authorities, preceding the formation
+of sugars. By reason of its greater complexity, however, it is more
+probable that the production of simple sugars precedes the formation of
+the more complex molecule. Starch granules are probably used as a food
+by the plant in the building of more complex structures and the excess
+of this food is stored in the seeds and in tubers.</p>
+
+<p><b>177. Separation of Starch Particles.</b>—Advantage is taken of the
+insolubility of the starch particles to secure their separation from
+the other vegetable structures with which they are associated. The
+substances containing starch are reduced to a pulp as fine as possible,
+and this pulp being placed in a fine cloth the starch particles are
+washed through the cloth with water. The milky filtrate carrying the
+starch is collected in an appropriate holder and, after some time, the
+particles subside. They may then be collected and dried. While this
+process is the one used commercially in the manufacture of starch, it
+can only give approximate data respecting the actual quantity of starch
+in a given weight of the sample. It is not quite possible by this
+method to get all the starch separated from the rest of the vegetable
+matter, and particles of foreign substances, such as cellulose and
+albuminoid matters, may pass through the filter cloth and be found
+with the deposited granules. It follows from this that the quantitive
+determination of the starch in a given sample by any direct method is
+only approximately exact.</p>
+
+<p><b>178. Methods of Separation.</b>—Hot acids cannot be safely employed
+to dissolve starch from its natural concomitants because other
+carbohydrate bodies become soluble under similar conditions. In such
+cases the natural sugars which are present should be removed by cold
+water and the starch dissolved from the residue by a diastatic ferment.
+Instead of this the sugars may be determined in a separate portion
+of the pulped material and the starch, together with the sugars, determined,
+and the quantity of sugar found deducted from the final result.
+<span class="pagenum"><a id="Page_198"></a>[Pg 198]</span></p>
+
+<p>In these cases the final determinations are made on the sugars, after
+inverting the sucrose, and proceeding as directed for invert sugars
+in paragraph <b><a href="#P_141">141</a></b>. The starch, after separation with diastase,
+is converted into dextrose by one of the methods to be given and the
+resulting dextrose determined by one of the approved methods.</p>
+
+<p id="P_179"><b>179. Separation with Diastase.</b>—Diastase or malt extract at
+a temperature of about 65° rapidly renders starch soluble. Cereals,
+potato meal and other starch-holding bodies are dried, first at a low
+temperature, and extracted with ether or petroleum to remove fat. The
+material is then rubbed up with water, boiled, cooled to 65°, and
+treated with malt extract (diastase) prepared as given below. One
+kilogram of ground green malt is mixed with one liter of glycerol
+and an equal quantity of water, and allowed to stand, with frequent
+shaking, for eight days. After that time the mixture is filtered,
+first through a small filter press and afterwards through paper. In
+case no filter press is at hand the mixture may be pressed in a bag
+and the liquor obtained, filtered. Malt extract obtained in this way
+will keep its diastatic properties for a long time. In its use, blank
+determinations must be made of the dextrose produced by treating equal
+portions of it with hydrochloric acid. For three grams of starchy
+material twenty-five cubic centimeters of the malt solution should be
+used and the mixture kept at 65° for two hours.<a id="FNanchor_146" href="#Footnote_146" class="fnanchor">[146]</a></p>
+
+<p><b>180. Method in Use at the Halle Station.</b>—The method of
+separating starch from cereals, potatoes and other starch-holding
+materials, employed at the Halle station, is essentially the same as
+already described.<a id="FNanchor_147" href="#Footnote_147" class="fnanchor">[147]</a></p>
+
+<p>The malt extract used is prepared immediately beforehand, inasmuch
+as no preservative is added to it. It can be quickly prepared by
+digesting, for a short time at not above 50°, 100 grams of finely
+ground dried malt with one liter of water and separating the extract by
+filtration. This extract will keep only a few hours.</p>
+
+<p>The material in which the starch is to be determined is dried and
+extracted with ether. From two to four grams of the extracted material,
+<span class="pagenum"><a id="Page_199"></a>[Pg 199]</span>
+according to the amount of starch which it contains, are boiled for
+half an hour with 100 cubic centimeters of water, cooled to 65°,
+treated with ten cubic centimeters of malt extract and kept at the
+temperature named for half an hour. It is then again boiled for fifteen
+minutes, cooled to the temperature mentioned and again treated with
+malt extract as above. Two treatments with malt extract are usually
+sufficient to bring all the starch into solution. Finally it is again
+boiled and the volume completed to 250 cubic centimeters and thrown
+upon a filter. Two hundred cubic centimeters of the filtrate are
+converted into dextrose by boiling with hydrochloric acid, and the rest
+of the analysis is conducted in the usual manner. The dextrose value of
+the quantity of malt extract used must be determined upon a separate
+portion thereof, and the quantity of dextrose found deducted from the
+total amount obtained in the analysis.</p>
+
+<div class="figleft smcap">
+    <img id="FIG_47A" src="images/fig47.jpg" alt="" width="200" height="366" >
+    <p class="center spb1">Figure 47.<br> Autoclave for<br> Starch Analysis.</p>
+</div>
+
+<p id="P_181"><b>181. Separation by Hydrolysis with Water at High
+Temperatures.</b>—Instead of dissolving the starch with diastase, it
+may be brought into solution by heating with water under pressure. The
+former method employed of heating in sealed flasks has been entirely
+superceded by heating in an autoclave. The materials are best held in
+metal beakers furnished with a cover which prevents loss from boiling
+if the pressure should be removed too rapidly after the completion
+of the operation. The autoclave is a strong metal vessel capable of
+resisting the pressure of several atmospheres. It is furnished with a
+pressure gauge C and a safety valve D, as shown in the <a href="#FIG_47A">figure</a>.
+The top is securely screwed on by means of a wrench, shown at the right hand
+<span class="pagenum"><a id="Page_200"></a>[Pg 200]</span>
+side. In the <a href="#FIG_47A">figure</a> a portion of the case is
+represented cut away to show the arrangement of the metal beakers
+inside.</p>
+
+<p>In the method of Reinke, as practiced at the Halle station, and in
+this laboratory, about three grams of the starchy substance are placed
+in each of the metal beakers with twenty-five cubic centimeters of
+a one per cent lactic acid solution and thirty cubic centimeters of
+water. The contents of the beaker are thoroughly mixed and they are
+then heated for two and a half hours in the autoclave, at a pressure
+of three and a half atmospheres. The addition of the lactic acid is
+for the purpose of protecting any sugar which may be present from
+decomposition at the high pressure and temperature employed. After
+the completion of the heating, the autoclave is allowed to cool, the
+cover is removed and the beakers taken out and their contents washed
+with hot water into quarter liter flasks. After cooling, the volume
+is completed with cold water, and after standing for half an hour,
+with frequent shaking, the contents of the flasks are filtered and
+200 cubic centimeters of the filtrate in each case converted into
+dextrose with hydrochloric acid in the usual way. In order to obtain
+agreeing results, it is highly necessary that the substance before
+treatment should be ground to a fine powder. The addition of the lactic
+acid, as practiced in the reinke method, tends to give somewhat high
+results, due probably to the hydrolytic action of the acid on the
+fiber present. When starchy bodies are heated in the autoclave for the
+determination of their starch by polarimetric methods, or for ordinary
+determinations, the use of lactic acid should be omitted.</p>
+
+<p><i>Example.</i>—The following data indicate the methods of calculation
+to be followed in the determination of the percentage of starch in the
+material by diastatic hydrolysis: Three grams of a barley were inverted
+by diastase, as directed above, the volume of the solution made a
+quarter of a liter, filtered, 200 cubic centimeters of the filtrate
+converted into dextrose by hydrochloric acid, the volume completed to
+half a liter with water and fifty cubic centimeters thereof oxidized
+by the alkaline copper solution in the usual way. The amount of copper
+obtained was 331 milligrams, corresponding to 174 milligrams of
+dextrose. The amount of malt extract used in hydrolyzing the barley
+<span class="pagenum"><a id="Page_201"></a>[Pg 201]</span>
+mentioned above, was ten cubic centimeters. The diastatic solution
+inverted with hydrochloric acid and treated as indicated above, yielded
+191 milligrams of copper, corresponding to ninety-eight milligrams of
+dextrose in ten cubic centimeters of the malt extract. The quantity of
+malt extract represented in the final determination of copper, however,
+was only one and six-tenths cubic centimeters. We then have:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Total dextrose</td>
+      <td class="tdr_wsp">&nbsp; 174</td>
+      <td class="tdr">milligrams</td>
+   </tr><tr>
+      <td class="tdl">Dextrose in one and six-tenths cubic centimeters</td>
+      <td class="tdr_wsp">&nbsp;</td>
+      <td class="tdr">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl_ws2">malt extract</td>
+      <td class="tdr_wsp">16</td>
+      <td class="tdr">milligrams</td>
+   </tr><tr>
+      <td class="tdl">Dextrose corresponding to 240 milligrams</td>
+      <td class="tdr_wsp">&nbsp;</td>
+      <td class="tdr">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl_ws2">of barley</td>
+      <td class="tdr_wsp">158</td>
+      <td class="tdr">milligrams</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Calculated on the proportion that dextrose is to starch, as ten is to
+nine, this is equivalent to 142 milligrams of starch. The percentage
+of starch in the original substance, therefore, was equivalent to 142
+multiplied by 100, divided by 240, <i>viz.</i>, 59.17.</p>
+
+<p><b>182. Principles of the Methods of Determination.</b>—In the
+approximately pure state in which starch exists in the trade, it may
+be determined by conversion into dextrose and estimating the latter
+by one of the methods given. It is probable that there is no known
+method by which starch can be entirely converted into dextrose, and
+all the methods of hydrolysis, when used for quantitive purposes,
+must be standardized, not by the theoretical quantity of dextrose
+which a given weight of pure starch should yield, but by the actual
+quantity obtained. Starch is not largely converted into dextrose by
+any of the diastatic ferments which produce principally maltose and
+dextrins. Recourse must therefore be had to strong acids. In practice,
+hydrochloric is the one usually employed. By the action of a hot
+mineral acid, not only is starch converted into dextrose, but also
+the dextrose found is subjected to changes. In such cases an opposing
+action seems to be exerted by the hydrolytic agent, a part of the
+dextrose formed suffering a partial condensation, and thus assuming
+a state of higher molecular weight, approaching the constitution of
+the dextrins. Another part of the dextrose may also suffer oxidation and
+thus disappear entirely in respect of the further steps in starch analysis.
+<span class="pagenum"><a id="Page_202"></a>[Pg 202]</span></p>
+
+<p>In such cases, the best the analyst can do is to conduct the hydrolysis
+in as nearly as possible constant conditions, and to assume that the
+percentage of dextrose present at a given time bears a constant ratio
+to the quantity of starch hydrolyzed. In reality almost all the starch
+appears finally as dextrose, and by proceeding on the assumption noted
+above a fairly satisfactory accounting may be made of the remainder.</p>
+
+<p>Starch being insoluble, it cannot be determined directly by its
+rotatory power. When heated for a few hours in contact with water at a
+high pressure, starch becomes soluble, and in this state has a fairly
+constant gyrodynat, <i>viz.</i>, [<i>a</i>]<span class="fs_80"><sub>D</sub></span> = 197°.</p>
+
+<p>Starch is also rendered soluble by rubbing it in a mortar for about ten
+minutes with an excess of strong hydrochloric acid, and in this way
+a quick approximate idea may be obtained of the percentage present.
+Starch prepared in this manner, however, has a strong reducing power
+on metallic salts, showing that a part of it has already, even in so
+short a time, assumed the state of maltose or dextrose. The gyrodynat
+of pure anhydrous starch in such conditions varies from [<i>a</i>]<span class="fs_80"><sub>D</sub></span>
+= 197° to [<i>a</i>]<span class="fs_80"><sub>D</sub></span> = 194°. Starch
+is also rendered soluble by boiling with salicylic acid, whereby a
+solution is obtained having a gyrodynat of [<i>a</i>]<span class="fs_80"><sub>D</sub></span> =
+200°(circa). The methods of procedure for the analysis of starch will
+be set forth in detail in the following paragraphs.</p>
+
+<p><b>183. Estimation of Water.</b>—In prepared or commercial starches
+the water may be determined by heating in a partial vacuum. The
+temperature at first should be low, not exceeding 60°. After drying
+for an hour at that heat the temperature may be gradually increased.
+The last traces of water come off from starch with difficulty, and the
+final temperature may be carried a little beyond 100° without danger of
+decomposition.</p>
+
+<p>Ost recommends the use of an atmosphere of hydrogen or illuminating
+gas.<a id="FNanchor_148" href="#Footnote_148" class="fnanchor">[148]</a>
+One and a half grams of the finely powdered sample are placed
+in the drying tube described in paragraph <b><a href="#P_23">23</a></b>, and heated in a
+stream of dry hydrogen. The temperature at first is kept at about 60°
+for several hours and is then gradually increased to 120°. Ost states
+that even at 150° the sample preserves its pure white color, but so
+high a temperature is not necessary. Maercker, at the Halle station,
+<span class="pagenum"><a id="Page_203"></a>[Pg 203]</span>
+makes use of the same process, but employs illuminating gas instead
+of hydrogen. The importance of beginning the desiccation at a low
+temperature arises from the fact that at a higher temperature, before
+the greater part of the water is driven off, the starch will suffer
+a partial fusion and form a paste which is very difficult to dry.
+The dried sample must be kept in a stoppered vessel to prevent the
+absorption of hygroscopic moisture.</p>
+
+<p><b>184. Estimation of Ash.</b>—When the drying is accomplished in
+a flat platinum dish, the same sample may serve for incineration.
+Otherwise the incineration may be accomplished in another portion of
+the sample by following directions already given.<a id="FNanchor_149" href="#Footnote_149" class="fnanchor">[149]</a></p>
+
+<p><b>185. Nitrogen.</b>—Even very pure samples of starch may contain
+a little nitrogen which is most conveniently determined by moist
+combustion.<a id="FNanchor_150" href="#Footnote_150" class="fnanchor">[150]</a></p>
+
+<p>As a rule, in commercial starches of good quality, the quantity of pure
+starch may be considered to be the remainder after subtracting the sum
+of the weights of water, ash and nitrogen multiplied by 6.25, from the
+original weight of the sample taken.</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl"><i>Example</i>:—</td>
+      <td class="tdl_wsp">&nbsp;</td>
+      <td class="tdr">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl_ws1">Per cent of</td>
+      <td class="tdl_wsp">moisture found</td>
+      <td class="tdr">12.85</td>
+   </tr><tr>
+      <td class="tdl_ws1">&nbsp; ”&emsp;&nbsp;”&emsp;”</td>
+      <td class="tdl_wsp">ash found</td>
+      <td class="tdr">0.08</td>
+   </tr><tr>
+      <td class="tdl_ws1">&nbsp; ”&emsp;&nbsp;”&emsp;”</td>
+      <td class="tdl_wsp">nitrogen × 6.25</td>
+      <td class="tdr bb">0.27</td>
+   </tr><tr>
+      <td class="tdc">Sum</td>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdr">13.20</td>
+   </tr><tr>
+      <td class="tdl_ws1">Per cent of</td>
+      <td class="tdl_wsp">pure starch in sample &nbsp;</td>
+      <td class="tdr">86.80</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Samples of starch usually contain also traces of fat and fiber, and
+these when present in weighable quantities, should be determined and
+proper deductions made.</p>
+
+<p id="P_186"><b>186. Hydrolysis with Acids.</b>—The acids commonly chosen for
+hydrolyzing starch are sulfuric and hydrochloric. The former has the
+advantage of being more easily removed from the finished product but
+the latter performs the work with less damage to the sugars formed. For
+commercial purposes sulfuric and for analytical practice hydrochloric
+acids are commonly employed.
+<span class="pagenum"><a id="Page_204"></a>[Pg 204]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_47B" src="images/fig47_2.jpg" alt="" width="300" height="402" >
+    <p class="center spb1">Figure 47 (bis). Maercker’s<br> Hydrolyzing Apparatus for Starch.</p>
+</div>
+
+<p>The best process for analytical purposes is the one proposed by
+Sachsse.<a id="FNanchor_151" href="#Footnote_151" class="fnanchor">[151]</a>
+In this method the starch is heated with the hydrolyzing mixture in
+the proportion of three grams to 200 cubic centimeters of water and
+twenty of hydrochloric acid of 1.125 specific gravity, containing five
+and six-tenths grams of the pure gas. The heating is continued for
+three hours on a steam-bath. Maercker recommends, instead of the above
+procedure, heating for two hours at gentle ebullition in an oil-bath.
+In this method three grams of the starch are reduced to paste with 200
+cubic centimeters of water, and then boiled for two hours with fifteen
+<span class="pagenum"><a id="Page_205"></a>[Pg 205]</span>
+cubic centimeters of hydrochloric acid of 1.125 specific gravity.
+The erlenmeyers in which the hydrolysis takes place are heated in an
+oil-bath and are provided with reflux condensers made of long glass
+tubes on which some bulbs have been blown, as shown in the accompanying
+<a href="#FIG_47B">figure</a>. In all cases after hydrolysis the
+solution is neutralized, made to a standard volume and an aliquot part,
+after filtration, diluted to contain an amount of dextrose suited
+to the use of the table by Allihn for calculating the percentage
+of sugar. In diluting the solution preparatory to the estimation
+of dextrose, it is well to remember that nine parts of starch will
+furnish theoretically ten parts of dextrose. Since three grams of the
+sample are used, containing approximately eighty-five per cent of
+starch, the quantity of dextrose present is a little less than three
+grams. The solution should therefore contain not less than 300 cubic
+centimeters.</p>
+
+<p><b>187. Factor for Calculating Starch from the Dextrose
+Obtained.</b>—If all the starch could be converted into dextrose
+without loss, the quantity of it could be easily calculated
+theoretically on the supposition that the formula of starch is
+<b>(C₆H₁₀O₅)ₙ</b>. The factor by this assumption is, starch = dextrose × 0.90.
+If the starch have the formula assigned to it by Nägeli, <i>viz.</i>,
+<b>C₃₆H₆₂O₃₁</b> the formula becomes, starch = dextrose × 0.918.</p>
+
+<p>Ost prefers to work by Sachsse’s method and to use the factor 0.925 to
+convert the dextrose into starch.<a id="FNanchor_152" href="#Footnote_152" class="fnanchor">[152]</a></p>
+
+<p>In view of all the facts in the case it appears that the analyst will
+reach nearly correct results by converting the starch into dextrose
+by heating for three hours at 100° with hydrochloric acid or for two
+hours at gentle ebullition as directed above, determining the resultant
+dextrose and multiplying the weight thereof by 0.92.</p>
+
+<p><b>188. Polarization of Starch.</b>—Starch may be prepared for
+polarization by dissolving it in cold hydrochloric acid. The process
+as carried out by Effront is as follows.<a id="FNanchor_153" href="#Footnote_153" class="fnanchor">[153]</a>
+Five grams of starch are rubbed with twenty cubic centimeters of
+cold concentrated hydrochloric acid for nearly ten minutes or until
+the solution is quite clear. The volume is completed to 200 cubic
+centimeters with water and the solution polarized. By this process
+there is always produced a notable quantity of reducing sugars, and for
+<span class="pagenum"><a id="Page_206"></a>[Pg 206]</span>
+this reason it must be admitted that a portion of the starch has
+suffered complete hydrolysis. Ost therefore recommends the use of an
+acid of 1.17 specific gravity, and the gyrodynat of the soluble starch
+thus produced is found to vary from [<i>a</i>]<span class="fs_80"><sub>D</sub></span>
+= 196°.3 to 196°.7. When acid of 1.20 specific gravity is employed the gyrodynat
+falls to [<i>a</i>]<span class="fs_80"><sub>D</sub></span> = 194.2.<a id="FNanchor_154" href="#Footnote_154" class="fnanchor">[154]</a>
+For approximately correct work the solution with the weaker hydrochloric
+acid and subsequent polarization is to be recommended as the most rapid
+method for starch determination.</p>
+
+<p>It will be of interest to add the observation that the gyrodynat
+of maltose has lately been redetermined by Ost, who finds it to be
+[<i>a</i>]<span class="fs_80"><sub>D</sub></span>²⁰ ° = 137°.04 ± 0.19.<a id="FNanchor_155" href="#Footnote_155" class="fnanchor">[155]</a></p>
+
+<p><b>189. Solutions of Starch at High Pressure.</b>—Starch may also be
+brought into a condition suited to polarization by dissolving in water
+at a high temperature and pressure. The solution is accomplished in an
+autoclave as described in <b><a href="#P_181">181</a></b>.</p>
+
+<p>From two to three grams of starch are used and from eighty to ninety
+cubic centimeters of water. The starch is first reduced to a pasty
+state by heating with the water and, when evenly distributed throughout
+the flask, is rendered soluble by heating from three to five hours in
+an autoclave at from two to three atmospheres. The material is entirely
+without action on an alkaline copper solution. After heating, the
+volume of the solution is completed to 100 cubic centimeters and it is
+then polarized. The gyrodynat of starch dissolved in this way varies
+from [<i>a</i>]<span class="fs_80"><sub>D</sub></span> = 196°.5 to 197°.<a id="FNanchor_156" href="#Footnote_156" class="fnanchor">[156]</a></p>
+
+<p>Starch is prepared by Baudry for polarization by boiling with
+salicylic acid.<a id="FNanchor_157" href="#Footnote_157" class="fnanchor">[157]</a>
+The gyrodynat of starch dissolved in this way is [<i>a</i>]<span class="fs_80"><sub>D</sub></span>
+= 200°.25.</p>
+
+<p><b>190. Polarization after Solution in Dilute Nitric
+Acid.</b>—Guichard recommends saccharification with ten per cent
+nitric acid (ten cubic centimeters strong acid, ninety cubic
+centimeters water).<a id="FNanchor_158" href="#Footnote_158" class="fnanchor">[158]</a>
+This treatment, even after prolonged boiling, gives only a light straw
+color to the solution which does not interfere with its polarization
+with a laurent instrument.</p>
+
+<p>In working on cereals four grams of the finely ground material, in
+which the bran and flour are intimately mixed, are used.</p>
+
+<p>The material is placed in a flask of about 500 cubic centimeters
+<span class="pagenum"><a id="Page_207"></a>[Pg 207]</span>
+capacity, with 100 cubic centimeters of the dilute acid. The flask is
+closed with a stopper carrying a reflux condenser. After boiling for
+an hour the contents of the flask are filtered and examined in the
+saccharimeter. The dextrose formed is determined by the polarimetric
+data and the quantity of starch transformed calculated from the
+dextrose. The following formula is used:</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>A</i> = &nbsp;</td>
+      <td class="tdc bb"><i>av</i> × 25 × 0.016</td>
+   </tr><tr>
+      <td class="tdc">2 × 52.8</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>In this formula <i>a</i> = the rotation in angular degrees, <i>v</i> =
+the volume of the liquid and <i>A</i> = the starch transformed.</p>
+
+<p>In this method no account is taken of the sucrose and other sugars
+which are present in cereals. In the case of sucrose the left-handed
+sugar produced by treatment with nitric acid would diminish the
+rotation to the right and thus introduce an error. On the other hand
+the dextrose formed from the fiber of the bran would be calculated as
+starch. If these two errors should be compensating the method might
+prove practical.</p>
+
+<p><b>191. Rapid Estimation Of Starch.</b>—For the rapid estimation of
+starch in cereals, cattle foods and brewery refuse, Hibbard recommends
+a method which is carried out as follows:</p>
+
+<p>The malt extract is prepared by covering ground, dry malt with water
+containing from fifteen to twenty per cent of alcohol. The object of
+adding alcohol is to preserve the filtered extract. It exercises a
+slight retarding effect on the action of the diastase, but prevents the
+malt extract from fermenting. After standing for a few hours in contact
+with the malt, the liquid is separated by filtration and is then ready
+for use. The substance in which the starch is to be determined should
+be dry enough to be finely pulverized, but previous extraction with
+ether is omitted. Enough of the material to contain at least half a
+gram of starch is placed in a flask with fifty cubic centimeters of
+water and from one to two cubic centimeters of malt extract added. The
+mixture is at once heated to boiling with frequent shaking to prevent
+the formation of clots. The addition of the diastase before boiling is
+to aid in preventing the formation of lumps. After boiling a minute the
+mixture is cooled to 60° and from two to three cubic centimeters of
+the malt extract added. It is then slowly heated until it again boils,
+<span class="pagenum"><a id="Page_208"></a>[Pg 208]</span>
+consuming about fifteen minutes, when, after cooling, it is tested
+with iodin for starch. If a blue color be produced the operation above
+described is repeated until it fails to reappear. The mixture is then
+made up to a standard volume, thrown on a linen filter and an aliquot
+part of the filtrate, representing from 200 to 300 milligrams of
+starch, is boiled with five cubic centimeters of hydrochloric acid, of
+thirty per cent strength, for half an hour. The total volume of the
+liquid before boiling should be completed to sixty cubic centimeters.
+By the method above described, it is claimed that the determination of
+starch in a cereal or similar substance can be completed within two
+hours. The chief amount of time saved is in the heating with the malt
+extract, which instead of being continued for two hours, as usually
+directed, can be accomplished in thirty
+minutes.<a id="FNanchor_159" href="#Footnote_159" class="fnanchor">[159]</a></p>
+
+<p><b>192. Precipitation of Starch with Barium Hydroxid.</b>—The tendency
+of carbohydrate bodies to unite with the earthy bases has been utilized
+by Asboth as a basis for the quantitive determination of
+starch.<a id="FNanchor_160" href="#Footnote_160" class="fnanchor">[160]</a></p>
+
+<p>About three grams of the finely ground sample containing the starch,
+or one gram of pure starch, are rubbed up in a mortar with water and
+the detached starch remaining suspended in the wash water is poured
+off. This operation is repeated until all the starch is removed. In
+difficult cases hot water may be used. The starch thus separated is
+heated in a quarter liter flask to the boiling point to reduce it to
+the condition of paste. When the paste is cold it is treated with fifty
+cubic centimeters of the barium hydroxid solution, the flask closed and
+well shaken for two minutes. The volume is then completed to the mark
+with forty-five per cent alcohol, the flask well shaken and allowed
+to stand. In a short time the barium-starch compound separates and
+settles. Fifty cubic centimeters of the clear supernatant liquor are
+removed with a pipette, or the liquor may be passed through a filter
+and the quantity mentioned removed for titration of the residual barium
+hydroxid after the addition of a few drops of phenolphthalein solution.</p>
+
+<p>The quantity of barium hydroxid remaining, deducted from the original
+quantity, gives the amount which has entered into composition with the
+<span class="pagenum"><a id="Page_209"></a>[Pg 209]</span>
+starch; the composition of the molecule being <b>BaOC₂₄H₄₀O₂₀</b>, which
+contains 19.10 per cent of barium oxid and 80.90 per cent of starch.</p>
+
+<p>The set solution of barium hydroxid must be preserved from contact with
+the carbon dioxid of the air. The burette should be directly attached
+to the bottle holding the set solution, by any of the usual appliances,
+and the air entering the bottle must be deprived of carbon dioxid. The
+water used in the work must be also free of air, and this is secured by
+boiling immediately before use.</p>
+
+<p class="blockquot"><i>Example.</i>—A sample of flour selected for
+the analysis weighed 3.212 grams. The starch was separated and reduced
+to paste in the manner described above. Thirty and four-tenths cubic
+centimeters of tenth-normal hydrochloric acid were exactly neutralized
+by ten cubic centimeters of the barium hydroxid solution. After
+treatment as above described, fifty cubic centimeters of the clear
+liquor, corresponding to ten cubic centimeters of the added barium
+hydroxid, required 19.05 cubic centimeters of tenth-normal hydrochloric
+acid. Then 30.4 - 19.05 = 11.35, and 11.35 x 5 = 56.75, which number
+corresponds to the total titration of the residual barium hydroxid in
+terms of tenth-normal hydrochloric acid. This number multiplied by
+0.0324, <i>viz.</i>, starch corresponding to one equivalent of barium,
+gave 1.8387 grams of starch or 57.24 per cent of the weight of flour employed.</p>
+
+<p>The barium hydroxid method has been given a thorough trial in this
+laboratory and the results have been unsatisfactory when applied to
+cereals. The principle of the process, however, appears to be sound,
+and with a proper variation of working details, it may become practical.</p>
+
+<p><b>193. Disturbing Bodies in Starch Determinations.</b>—Stone has made
+a comparison of the standard methods of starch determinations, and the
+results of his work show that in the case of pure starch all of the
+standard methods give approximately correct figures. For instance, in
+the case of a pure potato starch, the following data were obtained:</p>
+
+<p>By inversion with hydrochloric acid, 85.75 per cent; by inversion with
+oxalic and nitric acids, 85.75 per cent; by solution in salicylic acid,
+85.47 per cent; and by precipitation with barium hydroxid, 85.58 per
+cent.<a id="FNanchor_161" href="#Footnote_161" class="fnanchor">[161]</a></p>
+
+<p><span class="pagenum"><a id="Page_210"></a>[Pg 210]</span>
+When these methods are used, however, for the determination of starch
+in its original state, the widest variations are secured. Stone shows
+that these variations are due chiefly to the inverting effect of the
+reagents employed upon the pentosans present. In experiments made with
+pure xylan obtained from wheat straw, the methods employed gave from
+44.73 to 67.16 per cent of material, which would be calculated by
+the usual methods as starch. Stone also shows that the pentosans are
+practically unaffected by the action of diastase or malt extract. Pure
+xylan treated with diastase, under the condition in which starch is
+converted into maltose and other soluble carbohydrates, fails to give
+any subsequent reaction whatever with alkaline copper solution. In
+all cases, therefore, where starch occurs in conjunction with pentose
+bodies, it is necessary to separate it by diastatic action before
+applying any of the methods of conversion of the starch into dextrose
+or its precipitation by barium hydroxid.</p>
+
+<p><b>194. Colorimetric Estimation of Starch.</b>—The production of the
+intensely blue color which starch gives with iodin has been used not
+only as the basis of a qualitive method, but also of many attempts at
+quantitive determination. These attempts have, as a rule, been attended
+with very unsatisfactory results, due both to the extraordinary
+delicacy of the reaction and to the fact that starches of different
+origin do not always give exactly the same intensity of tint when
+present in the same quantity. At the present it must be admitted that
+little should be expected of any quantitive colorimetric test.</p>
+
+<p>In case such a test is desired the procedure described by Dennstedt
+and Voigtländer may be followed.<a id="FNanchor_162" href="#Footnote_162" class="fnanchor">[162]</a>
+A weighed quantity of the starch-holding material, containing
+approximately half a gram of starch, is placed in a two liter flask and
+boiled with a liter of water. After cooling, the volume is completed to
+two liters and the starch allowed to subside. Five cubic centimeters of
+the clear supernatant liquor are placed in a graduated cylinder holding
+100, and marked in half cubic centimeters. One drop of a solution of
+iodin in potassium iodid is added and the volume completed to the mark.
+A half gram of pure starch is treated in the same way and different
+<span class="pagenum"><a id="Page_211"></a>[Pg 211]</span>
+measured portions of the solution treated as above until the color of
+the first cylinder is matched. From the quantity of pure starch in
+the matched cylinder the quantity in the sample is determined. The
+test should be made in duplicate or triplicate. If a violet color be
+produced instead of a blue, it may be remedied by treating the sample
+with alcohol before the starch granules are dissolved.</p>
+
+<p><b>195. Fixation of Iodin.</b>—In addition to forming a distinctive
+blue color with iodin, starches have the power of fixing considerable
+quantities of that substance. The starches of the cereals have this
+power in a higher degree than those derived from potatoes. In presence
+of a large excess of iodin the starches of rice and wheat have a
+maximum iodin-fixing power of about nineteen per cent of their weight.
+When only enough of iodin is employed to enter into combination
+the percentage absorbed varies from nine to fifteen per cent. The
+absorption of iodin by starches is a matter of importance from a
+general chemical standpoint, but as at present determined has but
+little analytical value. It is evident, however, that this absorption
+must take place according to definite chemical quantities and the
+researches of investigators may in the future discover some definite
+quantitive method of measuring it.<a id="FNanchor_163" href="#Footnote_163" class="fnanchor">[163]</a></p>
+
+<p><b>196. Identification of Starches of Different Origin.</b>—It is
+often important, especially in cases of suspected adulteration, to
+determine the origin of the starch granules. For this purpose the
+microscope is the sole resort. In many cases it is easy to determine
+the origin of the starch by the size or the shape and marking of the
+grains. In mixtures of more than one kind of starch the distinguishing
+features of the several starches can be clearly made out in most
+instances. There are, however, many instances where it is impossible to
+discriminate by reason of the fact that the characteristics of starch
+granules vary even in the same substance and from year to year with
+varying conditions of culture.</p>
+
+<p>In many cases the illustrations of the forms and characteristics of
+starch granules which are found in books are misleading and no reliance
+can be placed on any illustrations which are not either photographs or
+drawings made directly from them. In the microscopic study of starches
+<span class="pagenum"><a id="Page_212"></a>[Pg 212]</span>
+the analyst will be greatly helped by the following descriptions of the
+characteristic appearance of the granules and the classifications based
+thereon.<a id="FNanchor_164" href="#Footnote_164" class="fnanchor">[164]</a></p>
+
+<p><b>197. Vogel’s Table of the Different Starches and Arrowroots of
+Commerce.</b>—<i>A.</i> Granules simple, bounded by rounded surfaces.</p>
+
+<ul class="index">
+<li class="isub1">I. Nucleus central, layers concentric.</li>
+<li class="isub2"><i>a.</i> Mostly round, or from the side, lens-shaped.</li>
+<li class="isub4">1. Large granules 0.0396-0.0528 mm, <i>rye starch</i>:</li>
+<li class="isub4">2. Large granules 0.0352-0.0396 mm, <i>wheat starch</i>:</li>
+<li class="isub4">3. Large granules 0.0264 mm, <i>barley starch</i>.</li>
+
+<li class="isub2"><i>b.</i> Egg-shaped, oval, kidney-shaped: Hilum often long and ragged:</li>
+<li class="isub4">1. Large granules 0.032-0.079 mm, <i>leguminous starches</i>.</li>
+
+<li class="isub1">II. Nucleus eccentric, layers plainly eccentric or meniscus-shaped.</li>
+<li class="isub2"><i>a.</i> Granules not at all or only slightly flattened:</li>
+<li class="isub4">1. Nucleus mostly at the smaller end; 0.06-0.10 mm, <i>potato starch</i>:</li>
+<li class="isub4">2. Nucleus mostly at the broader end or towards the middle</li>
+<li class="isub5">in simple granules; 0.022-0.060 mm, <i>maranta starch</i>.</li>
+
+<li class="isub2"><i>b.</i> Granules more or less strongly flattened.</li>
+<li class="isub4">1. Many drawn out to a short point at one end.</li>
+<li class="isub7"><i>a.</i> At most 0.060 mm long, <i>curcuma starch</i>:</li>
+<li class="isub7"><i>b.</i> As much as 0.132 mm long, <i>canna starch</i>:</li>
+<li class="isub4">2. Many lengthened to bean-shaped, disk-shaped, or flattened;</li>
+<li class="isub5">nucleus near the broader end; 0.044-0.075 mm, <i>banana starch</i>:</li>
+<li class="isub4">3. Many strongly kidney-shaped; nucleus near the edge;</li>
+<li class="isub5">0.048-0.056 mm, <i>sisyrinchium starch</i>:</li>
+<li class="isub4">4. Egg-shaped; at one end reduced to a wedge, at the other enlarged;</li>
+<li class="isub5">nucleus at smaller end; 0.05-0.07 mm, <i>yam starch</i>:</li>
+</ul>
+
+<p><i>B.</i> Granules simple or compound, single granules or parts of
+granules, either bounded entirely by plain surfaces, many-angled, or by
+partly round surfaces.
+<span class="pagenum"><a id="Page_213"></a>[Pg 213]</span></p>
+
+<ul class="index">
+<li class="isub1">I. Granules entirely angular.</li>
+<li class="isub2">1. Many with prominent nucleus: At most 0.0066 mm, <i>rice starch</i>:</li>
+<li class="isub2">2. Without a nucleus: The largest 0.0088 mm, <i>millet starch</i>:</li>
+
+<li class="isub1">II. Among the many-angled also rounded forms.</li>
+<li class="isub2"><i>a.</i> No drum-shaped forms present, angular form predominating.</li>
+<li class="isub4">1. Without nucleus or depression very small;</li>
+<li class="isub7">0.0044 mm, <i>oat starch</i>:</li>
+<li class="isub4">2. With nucleus or depression; 0.0132-0.0220 mm.</li>
+<li class="isub7"><i>a.</i> Nucleus or its depression considerably rounded;</li>
+<li class="isub9">here and there the granules united into differently</li>
+<li class="isub9">formed groups; <i>buckwheat starch</i>:</li>
+<li class="isub7"><i>b.</i> Nucleus mostly radiate or star-shaped; all the</li>
+<li class="isub9">granules free; <i>maize</i> (<i>corn</i>) <i>starch</i>:</li>
+
+<li class="isub2"><i>b.</i> More or less numerous kettledrum and sugar-loaf like forms.</li>
+<li class="isub4">1. Very numerous eccentric layers; the largest granules</li>
+<li class="isub7">0.022-0.0352 mm, <i>batata</i> (sweet potato) <i>starch</i>:</li>
+<li class="isub4">2. Without layers or rings; 0.008-0.022 mm.</li>
+<li class="isub6"><i>a.</i> In the kettledrum-shaped granules the nucleal</li>
+<li class="isub8">depression mostly widened on the flattened</li>
+<li class="isub8">side; 0.008-0.022 mm, <i>cassava starch</i>:</li>
+<li class="isub6"><i>b.</i> Depression wanting or not enlarged.</li>
+<li class="isub8"><i>aa.</i> Nucleus small, eccentric; 0.008-0.016 mm,</li>
+<li class="isub10"><i>pachyrhizus starch</i>:</li>
+<li class="isub8"><i>bb.</i> Nucleus small, central, or wanting.</li>
+<li class="isub10"><i>aaa.</i> Many irregular angular forms;</li>
+<li class="isub12">0.008-0.0176 mm, <i>sechium starch</i>:</li>
+<li class="isub10"><i>bbb.</i> But few angular forms; some with radiate,</li>
+<li class="isub12">nucleal fissure; 0.008-0.0176 mm, <i>chestnut starch</i>.</li>
+</ul>
+
+<p><i>C.</i> Granules simple and compound; predominant forms, oval, with
+eccentric nucleus and numerous layers; the compound granule made up
+of a large granule and one or more relatively small kettledrum-shaped
+ones; 0.025-0.066 mm, <i>sago starch</i>.
+<span class="pagenum"><a id="Page_214"></a>[Pg 214]</span></p>
+
+<p class="f120"><b>198. Muter’s Table for the Detection of Starches<br>
+                    when Magnified about 230 Diameters.</b></p>
+
+<p class="f90">[All measurements are given in decimals of an inch.]</p>
+
+<p class="center"><span class="fs_120"><i>Group I</i>:</span> All more or less
+oval in shape and having both hilum and rings visible.</p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb bt">Name.</th>
+      <th class="tdc bb bl bt">Shape.</th>
+      <th class="tdc bb bl bt">Normal<br>&nbsp;measurements.&nbsp;</th>
+      <th class="tdc bb bl bt">Remarks.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl bb">Tous les mois&nbsp;</td>
+      <td class="tdl_wsp bl bb">Oval, with flat ends</td>
+      <td class="tdc bl bb">0.00370<br> to 0.00185</td>
+      <td class="tdl_wsp bl bb">Hilum annular, near one<br>end and incomplete rings.</td>
+   </tr><tr>
+      <td class="tdl bb">Potato</td>
+      <td class="tdl_wsp bl bb">Oval</td>
+      <td class="tdc bl bb">0.00270<br>to 0.00148</td>
+      <td class="tdl_wsp bl bb">Hilum annular, rings incomplete,<br>
+                             shape and  size very variable.</td>
+   </tr><tr>
+      <td class="tdl bb">Bermuda<br>&emsp;arrowroot</td>
+      <td class="tdl_wsp bl bb">Sack-shaped</td>
+      <td class="tdc bl bb">0.00148<br>to 0.00129</td>
+      <td class="tdl_wsp bl bb">Hilum distinct annular, shape<br>variable, rings faint.</td>
+   </tr><tr>
+      <td class="tdl bb">St. Vincent<br>&emsp;arrowroot</td>
+      <td class="tdl_wsp bl bb">Oval-oblong</td>
+      <td class="tdc bl bb">0.00148<br>to 0.00129</td>
+      <td class="tdl_wsp bl bb">Hilum semi-lunar, rings faint,<br>
+                                shape not very variable.</td>
+   </tr><tr>
+      <td class="tdl bb">Natal<br>&emsp;arrowroot</td>
+      <td class="tdl_wsp bl bb">Broadly ovate</td>
+      <td class="tdc bl bb">0.00148<br>to 0.00129</td>
+      <td class="tdl_wsp bl bb">Hilum annular, in center and<br>
+                                well marked complete rings.</td>
+   </tr><tr>
+      <td class="tdl bb">Galangal</td>
+      <td class="tdl_wsp bl bb">Skittle-shaped</td>
+      <td class="tdc bl bb">About 0.00135</td>
+      <td class="tdl_wsp bl bb">Hilum elongated, very faint<br>incomplete rings.</td>
+   </tr><tr>
+      <td class="tdl bb">Calumba</td>
+      <td class="tdl_wsp bl bb">Broadly pear-shaped</td>
+      <td class="tdc bl bb">&nbsp; ”&emsp;0.00185</td>
+      <td class="tdl_wsp bl bb">Hilum semi-lunar, faint but<br>
+                                 complete rings, shape variable.</td>
+   </tr><tr>
+      <td class="tdl bb">Orris root</td>
+      <td class="tdl_wsp bl bb">Elongated-oblong</td>
+      <td class="tdc bl bb">&nbsp; ”&emsp;0.00092</td>
+      <td class="tdl_wsp bl bb">Hilum faint, shape characteristic.</td>
+   </tr><tr>
+      <td class="tdl bb">Turmeric</td>
+      <td class="tdl_wsp bl bb">Oval-oblong, conical</td>
+      <td class="tdc bl bb">&nbsp; ”&emsp;0.00148</td>
+      <td class="tdl_wsp bl bb">Very strongly marked<br>incomplete rings.</td>
+   </tr><tr>
+      <td class="tdl bb">Ginger</td>
+      <td class="tdl_wsp bl bb">Shortly conical, with&nbsp;<br>rounded angles.</td>
+      <td class="tdc bl bb">&nbsp; ”&emsp;0.00148</td>
+      <td class="tdl_wsp bl bb">Hilum and rings scarcely<br>visible, shape variable<br>
+                                but characteristic.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="spa2"><span class="pagenum"><a id="Page_215"></a>[Pg 215]</span></p>
+
+<p class="center"><span class="fs_120"><i>Group II</i>:</span> With strongly
+developed hilum more or less stellate.</p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb bt">Name.</th>
+      <th class="tdc bb bl bt">Shape.</th>
+      <th class="tdc bb bl bt">Normal<br>&nbsp;measurements.&nbsp;</th>
+      <th class="tdc bb bl bt">Remarks.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl bb">Bean</td>
+      <td class="tdl_wsp bl bb">Oval-oblong</td>
+      <td class="tdc bl bb">About 0.00135</td>
+      <td class="tdl_wsp bl bb">Fairly uniform.</td>
+   </tr><tr>
+      <td class="tdl bb">Pea</td>
+      <td class="tdl_wsp bl bb">Like bean</td>
+      <td class="tdc bl bb">0.00111<br>to 0.00074</td>
+      <td class="tdl_wsp bl bb">Very variable in size,with granules<br>under preponderating.</td>
+   </tr><tr>
+      <td class="tdl bb">Lentil</td>
+      <td class="tdl_wsp bl bb">Like bean</td>
+      <td class="tdc bl bb">About 0.00111</td>
+      <td class="tdl_wsp bl bb">Hilum, a long depression<br>seldom radiate.</td>
+   </tr><tr>
+      <td class="tdl bb">Nutmeg&emsp;&nbsp;</td>
+      <td class="tdl_wsp bl bb">Rounded</td>
+      <td class="tdc bl bb">&emsp;”&emsp;0.00055</td>
+      <td class="tdl_wsp bl bb">The small size and rounded<br>form distinctive.</td>
+   </tr><tr>
+      <td class="tdl bb">Dari</td>
+      <td class="tdl_wsp bl bb">Elongated hexagon</td>
+      <td class="tdc bl bb">&emsp;”&emsp;0.00074</td>
+      <td class="tdl_wsp bl bb">Irregular appearance and great<br>convexity distinctive.</td>
+   </tr><tr>
+      <td class="tdl bb">Maize</td>
+      <td class="tdl_wsp bl bb">Round and polygonal &nbsp;</td>
+      <td class="tdc bl bb">&emsp;”&emsp;0.00074</td>
+      <td class="tdl_wsp bl bb">The rounded angles of the<br>polygonalgranules distinctive.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="center spa2"><span class="fs_120"><i>Group III</i>:</span>
+Hilum and rings practically invisible.</p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb bt">Name.</th>
+      <th class="tdc bb bl bt">Shape.</th>
+      <th class="tdc bb bl bt">Normal<br>&nbsp; measurements. &nbsp;</th>
+      <th class="tdc bb bl bt">Remarks.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl bb">Wheat</td>
+      <td class="tdl_wsp bl bb">Circular and flat</td>
+      <td class="tdc bl bb">0.00185<br>to 0.00009</td>
+      <td class="tdl_wsp bl bb">Very variable in size and very dull<br> polarization in water.</td>
+   </tr><tr>
+      <td class="tdl bb">Barley</td>
+      <td class="tdl_wsp bl bb">Slightly angular circles &nbsp;</td>
+      <td class="tdc bl bb">About 0.00073</td>
+      <td class="tdl_wsp bl bb">The majority measuring about 0.00373<br>
+                           distinctive, and a few four times<br>this size.</td>
+   </tr><tr>
+      <td class="tdl bb">Rye</td>
+      <td class="tdl_wsp bl bb">Like barley</td>
+      <td class="tdc bl bb">0.00148<br>to 0.00009</td>
+      <td class="tdl_wsp bl bb">Small granules, quite round,<br>and here and there cracked.</td>
+   </tr><tr>
+      <td class="tdl bb">Jalap</td>
+      <td class="tdl_wsp bl bb">Like wheat</td>
+      <td class="tdc bl bb">&nbsp;</td>
+      <td class="tdl_wsp bl bb">Polarizes brightly in water.</td>
+   </tr><tr>
+      <td class="tdl bb">Rhubarb</td>
+      <td class="tdl_ws2 bl bb">do.</td>
+      <td class="tdc bl bb">0.00055<br>to 0.00033</td>
+      <td class="tdl_wsp bl bb">Polarizes between jalap and wheat,<br>
+                                 and runs smaller and more convex.</td>
+   </tr><tr>
+      <td class="tdl">Senega</td>
+      <td class="tdl_wsp bl">Like wheat</td>
+      <td class="tdc bl">0.00148-0.00009</td>
+      <td class="tdl_wsp bl bb" rowspan="3">Measurements the only guide.</td>
+   </tr><tr>
+      <td class="tdl">Bayberry</td>
+      <td class="tdl_ws2 bl">do.</td>
+      <td class="tdc bl">0.00074-0.00011</td>
+   </tr><tr>
+      <td class="tdl bb">Sumbul</td>
+      <td class="tdl_ws2 bl bb">do.</td>
+      <td class="tdc bl bb">0.00074-0.00009</td>
+   </tr><tr>
+      <td class="tdl bb">Chestnut</td>
+      <td class="tdl_wsp bl bb">Very variable</td>
+      <td class="tdc bl bb">0.00090-0.00009</td>
+      <td class="tdl_wsp bl bb">Variable form, and small but<br>regular size, distinctive.</td>
+   </tr><tr>
+      <td class="tdl bb">Acorn</td>
+      <td class="tdl_wsp bl bb">Round-oval</td>
+      <td class="tdc bl bb">About 0.00074</td>
+      <td class="tdl_wsp bl bb">Small and uniform size, distinctive.</td>
+   </tr><tr>
+      <td class="tdl bb">Calabar bean</td>
+      <td class="tdl_wsp bl bb">Oval-oblong</td>
+      <td class="tdc bl bb">0.00296<br>to 0.00180</td>
+      <td class="tdl_wsp bl bb">Large size and shape characteristic.</td>
+   </tr><tr>
+      <td class="tdl bb">Licorice</td>
+      <td class="tdl_wsp bl bb">Elongated-oval</td>
+      <td class="tdc bl bb">About 0.00018</td>
+      <td class="tdl_wsp bl bb">Small size and shape distinctive.</td>
+   </tr><tr>
+      <td class="tdl bb">Hellebore<br>&nbsp; (green or black)</td>
+      <td class="tdl_wsp bl bb">Perfectly rotund</td>
+      <td class="tdc bl bb">0.00037<br>to 0.00009</td>
+      <td class="tdl_wsp bl bb">Small, regular size and rotundity,<br>distinctive.</td>
+   </tr><tr>
+      <td class="tdl bb">Hellebore<br>&nbsp; (white)</td>
+      <td class="tdl_wsp bl bb">Irregular</td>
+      <td class="tdc bl bb">0.00055<br>to 0.00009</td>
+      <td class="tdl_wsp bl bb">Irregular shape and faint central<br>
+                      depression, distinctive.</td>
+   </tr>
+ </tbody>
+</table>
+<p class="spa2"><span class="pagenum"><a id="Page_216"></a>[Pg 216]</span></p>
+
+<p class="center spa2"><span class="fs_120"><i>Group IV</i>:</span>
+More or less truncated at one end.</p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb bt">Name.</th>
+      <th class="tdc bb bl bt">Shape.</th>
+      <th class="tdc bb bl bt">Normal<br>&nbsp; measurements. &nbsp;</th>
+      <th class="tdc bb bl bt">Remarks.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl bb">Cassia</td>
+      <td class="tdl_wsp bl bb">Round</td>
+      <td class="tdc bl bb">0.00111<br>to 0.00018</td>
+      <td class="tdl_wsp bl bb">Round or muller shaped granules<br>and faint circular hilum.</td>
+   </tr><tr>
+      <td class="tdl bb">Cinnamon</td>
+      <td class="tdl_wsp bl bb">Like cassia</td>
+      <td class="tdc bl bb">0.00074<br>to 0.00009</td>
+      <td class="tdl_wsp bl bb">More frequently truncated than<br>cassia, and smaller.</td>
+   </tr><tr>
+      <td class="tdl bb">Sago (raw)</td>
+      <td class="tdl_wsp bl bb">Oval-ovate</td>
+      <td class="tdc bl bb">0.00260 <br>to 0.00111</td>
+      <td class="tdl_wsp bl bb">Has circular hilum at convex end<br>and rings faintly visible.</td>
+   </tr><tr>
+      <td class="tdl bb">Sago (prepared)&nbsp;</td>
+      <td class="tdl_ws2 bl bb">”</td>
+      <td class="tdc bl bb">0.00260<br>to 0.00111</td>
+      <td class="tdl_wsp bl bb">Has a large oval or circular depression,<br>
+                              covering one-third nearly of each granule.</td>
+   </tr><tr>
+      <td class="tdl bb">Tapioca</td>
+      <td class="tdl_wsp bl bb">Roundish</td>
+      <td class="tdc bl bb">0.00074<br>to 0.00055</td>
+      <td class="tdl_wsp bl bb">A little over fifty per cent truncated<br>
+                                      by one facet, and a pearly hilum.</td>
+   </tr><tr>
+      <td class="tdl bb">Arum</td>
+      <td class="tdl_wsp bl bb">Like tapioca</td>
+      <td class="tdc bl bb">About 0.00056</td>
+      <td class="tdl_wsp bl bb">Smaller than tapioca and truncated<br>by two facets.</td>
+   </tr><tr>
+      <td class="tdl bb">Belladonna</td>
+      <td class="tdl_ws2 bl bb">do.</td>
+      <td class="tdc bl bb">&nbsp;</td>
+      <td class="tdl_wsp bl bb">Not distinguishable from tapioca.</td>
+   </tr><tr>
+      <td class="tdl bb">Colchicum</td>
+      <td class="tdl_ws2 bl bb">do.</td>
+      <td class="tdc bl bb">About 0.00074</td>
+      <td class="tdl_wsp bl bb">Larger than tapioca, and contains<br>
+                                          many more truncated granules.</td>
+   </tr><tr>
+      <td class="tdl bb">Scammony</td>
+      <td class="tdl_ws2 bl bb">do.</td>
+      <td class="tdc bl bb">&nbsp; ”&emsp;0.00045</td>
+      <td class="tdl_wsp bl bb">Smaller than tapioca, more irregular,<br>
+                               and hilum not visible.</td>
+   </tr><tr>
+      <td class="tdl bb">Cancella</td>
+      <td class="tdl_wsp bl bb">Very variable&nbsp;</td>
+      <td class="tdc bl bb">0.00033-0.00022</td>
+      <td class="tdl_wsp bl bb">Very variable, form and small size<br>the only points.</td>
+   </tr><tr>
+      <td class="tdl bb">Podophyllum</td>
+      <td class="tdl_wsp bl bb">Like tapioca</td>
+      <td class="tdc bl bb">About 0.00040</td>
+      <td class="tdl_wsp bl bb">Like scammony, but has visible hilum<br>
+                               in most of the granules.</td>
+   </tr><tr>
+      <td class="tdl bb">Aconite</td>
+      <td class="tdl_ws2 bl bb">do.</td>
+      <td class="tdc bl bb">&nbsp; ”&emsp;0.00037</td>
+      <td class="tdl_wsp bl bb">Like tapioca, but half the size.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="spa2"><span class="pagenum"><a id="Page_217"></a>[Pg 217]</span></p>
+
+<p class="center spa2"><span class="fs_120"><i>Group V</i>:</span>
+All granules more or less polygonal.</p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb bt">Name.</th>
+      <th class="tdc bb bl bt">Shape.</th>
+      <th class="tdc bb bl bt">Normal<br>&nbsp; measurements. &nbsp;</th>
+      <th class="tdc bb bl bt">Remarks.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl bb">Tacca</td>
+      <td class="tdl_wsp bl bb">Poly- or hexagonal &nbsp;</td>
+      <td class="tdc bl bb">0.00075<br>to 0.00037</td>
+      <td class="tdl_wsp bl bb">Distinguished from maize by<br>its sharp angles.</td>
+   </tr><tr>
+      <td class="tdl bb">Oat</td>
+      <td class="tdl_wsp bl bb">Polygonal</td>
+      <td class="tdc bl bb">About 0.00037</td>
+      <td class="tdl_wsp bl bb">Larger than rice and  hilum visible<br>in some granules.</td>
+   </tr><tr>
+      <td class="tdl bb">Rice></td>
+      <td class="tdl_ws2 bl bb">do.</td>
+      <td class="tdc bl bb">0.00030-0.00020</td>
+      <td class="tdl_wsp bl bb">Measurement using one-eighth or<br>
+                         one-twelfth inch power, and then<br>hilum visible.</td>
+   </tr><tr>
+      <td class="tdl bb">Pepper</td>
+      <td class="tdl_ws2 bl bb">do.</td>
+      <td class="tdc bl bb">0.00020-0.00002</td>
+      <td class="tdl_ws2 bl bb">Do.</td>
+   </tr><tr>
+      <td class="tdl bb">Ipecacuanha &nbsp;</td>
+      <td class="tdl_ws2 bl bb">do.</td>
+      <td class="tdc bl bb">About 0.00018</td>
+      <td class="tdl_wsp bl bb">Some round and truncated granules,<br>
+                           adhering in groups of three.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_218"></a>[Pg 218]</span>
+<b>199. Blyth’s Classification.</b>—Blyth gives the following scheme
+for the identification of starch granules by their microscopic
+appearance.<a id="FNanchor_165" href="#Footnote_165" class="fnanchor">[165]</a></p>
+
+<p><i>Division I.—Starches showing a play of colors with polarized light
+and selenite plate</i>:</p>
+
+<p>The hilum and concentric rings are clearly visible, and all the starch
+granules, oval or ovate. Canna arrowroot, potato, arrowroot, calumba,
+orris root, ginger, galangal and turmeric belong to this division.</p>
+
+<p><i>Division II.—Starches showing no iridescence, or scarcely any, when
+examined by polarized light and selenite</i>:</p>
+
+<p>Class I.—The concentric rings are all but invisible, and the hilum
+stellate. The bean, pea, maize, lentil, dari and nutmeg starches are in
+this class.</p>
+
+<p>Class II.—Starches which have both the concentric rings and hilum
+invisible in the majority of granules: this important class includes
+wheat, barley, rye, chestnut, acorn, and many starches in medicinal plants.</p>
+
+<p>Class III.—All the granules are truncated at one end. This class
+includes sago, tapioca and arum, several drugs and cinnamon and cassia.</p>
+
+<p>Class IV.—In this class all the granules are angular in form and it
+includes oats, tacca, rice, pepper and ipecacuanha.</p>
+
+<p><b>200. Preparation of Starches for Microscopical Examination.</b>—The
+approximately pure starches of commerce may be prepared for microscopic
+examination by rubbing them up with water and mounting some of the
+suspended particles by one of the methods to be described below.</p>
+
+<p>In grains, seeds and nuts the starch is separated by grinding with
+water and working through fine linen. The starch which is worked
+through is allowed to subside, again beaten up with water if necessary
+and the process continued until the grains are separated sufficiently
+for microscopic examination. A little potash or soda lye may be used,
+if necessary, to separate the granules from albuminous and other
+adhering matter. The analyst should have a collection of samples of all
+common starches of known origin for purposes of comparison.
+<span class="pagenum"><a id="Page_219"></a>[Pg 219]</span></p>
+
+<p>The granules are mounted for examination by plain light in a medium
+of glycerol and camphor water. When polarized light is used the
+mounting should be in Canada balsam.<a id="FNanchor_166" href="#Footnote_166" class="fnanchor">[166]</a>
+The reader can find excellent photomicrographs of the more common starches
+in Griffith’s book.<a id="FNanchor_167" href="#Footnote_167" class="fnanchor">[167]</a></p>
+
+<p><b>201. Appearance in Balsam with Polarized Light.</b>—Mounted in
+balsam the starches are scarcely visible under any form of illumination
+with ordinary light, the index of refraction of the granules and the
+balsam being so nearly alike. When, however, polarized light is used
+the effect is a striking one. It is very easy to distinguish all the
+characteristics, except the rings, the center of the cross being at the
+nucleus of the granule.</p>
+
+<p>With the selenite plate a play of colors is produced, which is peculiar
+to some of the starches and forms the basis of Blyth’s classification.</p>
+
+<p><b>202. Description Of Typical Starches.</b>—The more commonly
+occurring starches are described by Richardson as they appear under the
+microscope magnified about 350
+diameters.<a id="FNanchor_168" href="#Footnote_168" class="fnanchor">[168]</a></p>
+
+<p>The illustrations, with the exception of the cassava starch, and the
+maize starch accompanying it were drawn by the late Dr. Geo. Marx from
+photographs made by Richardson in this laboratory. The two samples
+excepted were photographed for the author by Dr. G. L. Spencer.</p>
+
+<p><i>Maranta Starch.</i>—Of the same type as the potato starch are the
+various arrowroots, the only one of which commonly met with in this
+country being the Bermuda, the starch of the rhizome of <i>Maranta
+arundinacea</i>, and the starch of turmeric.</p>
+
+<p>The granules are usually not so varied in size or shape as those of
+the potato, averaging about 0.07 millimeter in length as may be seen
+in <a href="#FIG_48">Fig. 48</a>. They are about the same size as the average of
+the potato, but are not often found with the same maximum or minimum magnitude,
+which circumstance, together with the fact that the end at which the
+nucleus appears is broader in the maranta and more pointed in the
+potato, enables one to distinguish the two starches without difficulty.
+With polarized light the results are similar to those seen with potato
+starch, and this is a ready means of distinguishing the two varieties,
+<span class="pagenum"><a id="Page_220"></a>[Pg 220]</span>
+by displaying in a striking way the form of the granule and position of
+the hilum.</p>
+
+<p><i>Potato Starch.</i>—The starch grains of the potato are very
+variable in size, being found from 0.05 to 0.10 millimeter in length,
+and in shape from oval and allied forms to irregular and even round
+in the smallest. These variations are illustrated in <a href="#FIG_49">Fig. 49</a>,
+but the frequency of the smaller granules is not as evident as in some other
+cases. The layers are visible in some granules with great distinctness
+and in others hardly at all, being rather more prominent in the starch
+as obtained from a freshly cut surface. The rings are more distinct,
+too, near the hilum or nucleus, which in this, as in all tuberous
+starches, is eccentric, shading off toward the broader or more expanded
+portion of the granule. The hilum appears as a shadowy depression,
+and with polarized light its position is well marked by the junction
+of the arms of the cross. With polarized light and a selenite plate a
+beautiful play of colors is obtained. The smaller granules, which are
+nearly round, may readily be confused with other starches, but their
+presence serves at once to distinguish this from maranta or Bermuda
+arrowroot starch. Rarely compound granules are found composed of two or
+three single ones each with its own nucleus.</p>
+
+<p><i>Ginger Starch.</i>—This starch is of the same class as those from
+the potato and maranta and several others which are of underground
+origin. In outline the granules are not oval like those named, but more
+rectangular, having more obtuse angles in the larger ones and being
+cylindrical or circular in outline in the smaller, as indicated in <a href="#FIG_50">Fig. 50</a>.
+They average nearly the same size as maranta starch, but are much
+more variable, both in size and form. The rings are scarcely visible
+even with the most favorable illuminations.</p>
+
+<p><i>Sago Starch.</i>—This exists in two modifications in the market; as
+raw and as prepared sago. In the prepared condition it is characterized
+by a larger circular depression in the center of most of the granules.
+The rings are not visible. They are mostly circular in form or
+approaching it, and vary from 0.025 to 0.065 millimeter in diameter, as
+indicated in <a href="#FIG_51">Fig. 51</a>.</p>
+
+<div class="figcontainer smcap">
+  <div class="figsub">
+   <p id="FIG_48" class="center"><b>Fig. 48.</b><br>&nbsp;</p>
+   <img src="images/fig48.jpg" alt="" width="300" height="251" >
+   <p class="center">Maranta Starch × 350.</p>
+  </div>
+  <div class="figsub">
+   <p id="FIG_49" class="center"><b>Fig. 49.</b></p>
+   <img src="images/fig49.jpg" alt="" width="300" height="263" >
+   <p class="center">Potato Starch × 350.</p>
+   </div>
+</div>
+
+<div class="figcontainer smcap">
+  <div class="figsub">
+   <p id="FIG_50" class="center"><b>Fig. 50.</b><br>&nbsp;</p>
+   <img src="images/fig50.jpg" alt="" width="300" height="185" >
+   <p class="center">&nbsp;<br>Ginger Starch × 350.</p>
+  </div>
+  <div class="figsub">
+   <p id="FIG_51" class="center"><b>Fig. 51.</b></p>
+   <img src="images/fig51.jpg" alt="" width="300" height="239" >
+   <p class="center">Sago Starch × 350.</p>
+   </div>
+</div>
+
+<div class="figcontainer smcap">
+  <div class="figsub">
+   <p id="FIG_52" class="center"><b>Fig. 52.</b></p>
+   <img src="images/fig52.jpg" alt="" width="300" height="279" >
+   <p class="center">Pea Starch × 350.</p>
+  </div>
+  <div class="figsub">
+   <p id="FIG_53" class="center"><b>Fig. 53.</b></p>
+   <img src="images/fig53.jpg" alt="" width="300" height="278" >
+   <p class="center">Bean Starch × 350.</p>
+   </div>
+</div>
+
+<p class="center"><b>DRAWN BY GEO. MARX</b>.<span class="ws3">A. Hoen &amp; Co., Lithocaustic</span></p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="figcontainer smcap">
+  <div class="figsub">
+   <p id="FIG_54" class="center"><b>Fig. 54.</b></p>
+   <img src="images/fig54.jpg" alt="" width="300" height="312" >
+   <p class="center">Wheat Starch × 350.</p>
+  </div>
+  <div class="figsub">
+   <p id="FIG_55" class="center"><b>Fig. 55.</b></p>
+   <img src="images/fig55.jpg" alt="" width="250" height="330" >
+   <p class="center">Barley Starch × 350.</p>
+   </div>
+</div>
+
+<div class="figcontainer smcap">
+  <div class="figsub">
+   <p id="FIG_56" class="center"><b>Fig. 56.</b></p>
+   <img src="images/fig56.jpg" alt="" width="300" height="289" >
+   <p class="center">Rye Starch × 350.</p>
+  </div>
+  <div class="figsub">
+   <p id="FIG_57" class="center"><b>Fig. 57.</b></p>
+   <img src="images/fig57.jpg" alt="" width="300" height="278" >
+   <p class="center">Oat Starch × 350.</p>
+   </div>
+</div>
+
+<div class="figcontainer smcap">
+  <div class="figsub">
+   <p id="FIG_58" class="center"><b>Fig. 58.</b><br>&nbsp;</p>
+   <img src="images/fig58.jpg" alt="" width="300" height="220" >
+   <p class="center">Indian Corn Starch × 350.</p>
+  </div>
+  <div class="figsub">
+   <p id="FIG_59" class="center"><b>Fig. 59.</b></p>
+   <img src="images/fig59.jpg" alt="" width="250" height="248" >
+   <p class="center">Rice Starch × 350.</p>
+   </div>
+</div>
+
+<p class="center"><b>DRAWN BY GEO. MARX</b>.<span class="ws3">A. Hoen &amp; Co.,
+Lithocaustic</span></p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="figcenter smcap">
+    <p class="center"><b>FIG. 60.</b></p>
+    <img id="FIG_60" src="images/fig60.jpg" alt="" width="400" height="380" >
+    <p class="center">Cassava Starch × 150.</p>
+    <p class="f80 spb1">PLAIN ILLUMINATION.</p>
+    <p class="center"><b>FIG. 61.</b></p>
+    <img id="FIG_61" src="images/fig61.jpg" alt="" width="400" height="380" >
+    <p class="center">Indian Corn Starch × 150.</p>
+    <p class="f80 spb1">PLAIN ILLUMINATION.</p>
+</div>
+
+<p class="center spb2">A. Hoen &amp; Co., Lithocaustic</p>
+
+<p><span class="pagenum"><a id="Page_221"></a>[Pg 221]</span>
+<i>Pea and Bean Starches.</i>—These starches produce but a slight
+effect with polarized light. The rings are scarcely visible, and the
+hilum is stellate or much cracked along a median line, the bean more so
+than the pea, the latter resembling fresh dough kneaded again into the
+center as in making rolls, and the former the shape assumed by the same
+after baking. The grains of both are somewhat variable in size, ranging
+from 0.025 to 0.10 millimeter in length, as shown in
+Figs. <a href="#FIG_52">52</a> and <a href="#FIG_53">53</a>.</p>
+
+<p><i>Wheat Starch</i> grains are quite variable in size, varying from
+0.05 to 0.010 millimeter in diameter. They belong to the same class as
+barley and rye, the hilum being invisible and the rings not prominent.
+The granules are circular disks in form, and there are now and then
+contorted depressions resembling those in pea starch. They are the
+least regular of the three starches named and do not polarize actively.
+The typical forms of these granules are shown in <a href="#FIG_54">Fig. 54</a>.</p>
+
+<p><i>Barley Starch</i> is quite similar to that of wheat, but the grains
+do not vary so much in size, averaging 0.05 millimeter. They have rings
+which are much more distinct, and very small granules adhering to the
+largest in bud-like forms, as seen in <a href="#FIG_55">Fig. 55</a>.</p>
+
+<p><i>Rye Starch</i> is more variable in size, many of the granules
+not exceeding 0.02 millimeter, while the largest reach 0.06 to 0.07
+millimeter. It lacks distinctive characteristics entirely, and is the
+most simple in form of all the starches. <a href="#FIG_56">Fig. 56</a>
+shows the appearance of the granules under the microscope.</p>
+
+<p><i>Oat Starch</i> is unique, being composed of large compound masses of
+polyhedral granules from 0.12 to 0.02 millimeter in length, the single
+granules averaging 0.02 to 0.015 millimeter. It does not polarize
+actively, and displays neither rings nor hilum. The illustration,
+<a href="#FIG_57">Fig. 57</a>, shows its nature with accuracy.</p>
+
+<p><i>Indian Corn Starch.</i>—The granules of maize starch are largely
+of the same size, from 0.02 to 0.03 millimeter in diameter, with now
+and then a few which are much smaller. They are mostly circular in
+shape or rather polyhedral, with rounded angles, as shown in Figs. <a href="#FIG_58">58</a>
+and <a href="#FIG_61">61</a>. They form very brilliant objects with polarized light, but
+with ordinary illumination show but the faintest sign of rings and a
+well-developed hilum, at times star-shaped, and at others more like a
+circular depression.</p>
+
+<p><i>Rice Starch</i> is very similar to that of maize, and is easily
+<span class="pagenum"><a id="Page_222"></a>[Pg 222]</span>
+confused with it, the grains being about the same size. The grain,
+however, is distinguished from it by its polygonal form, and its
+well defined angles, as indicated in <a href="#FIG_59">Fig. 59</a>.
+The hilum is more prominent and more often stellate or linear. Several
+granules are at times united.</p>
+
+<p><i>Cassava Starch.</i>—This variety of starch is obtained from
+the root of the sweet cassava, which grows in great profusion in
+Florida. It is compared with maize starch in Figs. <a href="#FIG_60">60</a>
+and <a href="#FIG_61">61</a>. In the illustration the granules are
+represented as magnified 150 diameters. The grains of the cassava
+starch measure about 0.012 millimeter in diameter and resemble very
+nearly maize starch, except that they have greater evenness of
+outline.<a id="FNanchor_169" href="#Footnote_169" class="fnanchor">[169]</a></p>
+
+<p>For further descriptions of starch grains the reader is referred to the
+work of Griffith, already cited.</p>
+
+<p>These descriptions, it will be seen, do not agree entirely with those
+of some other authors, but they are based on a somewhat extensive experience.</p>
+
+<p>There are peculiarities of size, shape and appearance of starch
+granules, which must be allowed for, and the necessity for every
+investigator to compare a starch which he is desirous of identifying
+with authentic specimens, must always be recognized.</p>
+
+<h3>AUTHORITIES CITED IN PART SECOND.</h3>
+
+<div class="footnotes">
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_23" href="#FNanchor_23" class="label">[23]</a>
+Vines, Vegetable Physiology.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_24" href="#FNanchor_24" class="label">[24]</a>
+Berichte der deutschen chemischen Gesellschaft, Band 23, S. 2136;
+Stone, Agricultural Science Vol. 6, p. 180. Page 59, eighth line from
+bottom insert “original” before “optical.” Page 60, second line from
+top, read <i>d</i> instead of <i>l</i> fructose.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_25" href="#FNanchor_25" class="label">[25]</a>
+Herles, Zeitschrift des Vereins für die Rübenzucker-Industrie,
+1890. S. 217.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_26" href="#FNanchor_26" class="label">[26]</a>
+Tucker; Wiechmann; Sidersky; von Lippman; Tollens and Spencer.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_27" href="#FNanchor_27" class="label">[27]</a>
+Bulletin No. 28, Department of Agriculture, Division of Chemistry, p. 197.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_28" href="#FNanchor_28" class="label">[28]</a>
+Physikalisch-Chemische Tabellen, S. 42.</p>
+</div>
+
+<div class="footnote"><p class="no-indent"><a id="Footnote_29" href="#FNanchor_29" class="label">[29]</a>
+Tucker’s Manual of Sugar Analysis, pp. 100 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_30" href="#FNanchor_30" class="label">[30]</a>
+Vid. op. cit. supra, p. 108.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_31" href="#FNanchor_31" class="label">[31]</a>
+Op. cit. supra, p. 109.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_32" href="#FNanchor_32" class="label">[32]</a>
+Op. cit. supra, p. 110.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_33" href="#FNanchor_33" class="label">[33]</a>
+Op. cit. supra, p. 114.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_34" href="#FNanchor_34" class="label">[34]</a>
+Spencer’s Handbook for Sugar Manufacturers, p. 92.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_223"></a>[Pg 223]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_35" href="#FNanchor_35" class="label">[35]</a>
+Landolt’s Handbook of the Polariscope, pp. 95 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_36" href="#FNanchor_36" class="label">[36]</a>
+Robb, vid. op. cit. supra, p. 8.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_37" href="#FNanchor_37" class="label">[37]</a>
+Spencer’s Handbook for Sugar Manufacturers, pp. 22 et seq.
+Tucker’s Manual of Sugar Analysis, pp. 120 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_38" href="#FNanchor_38" class="label">[38]</a>
+Sidersky; Traité d’Analyse des Matières Sucrées, p. 104.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_39" href="#FNanchor_39" class="label">[39]</a>
+Journal of the American Chemical Society, 1893. Vol. 15, p. 121.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_40" href="#FNanchor_40" class="label">[40]</a>
+Comptes rendus, 1879. Seance du 20th Octobre 1879;
+Dingler’s polytechniches Journal, Band 223, S. 608.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_41" href="#FNanchor_41" class="label">[41]</a>
+Landolt’s Handbook of the Polariscope. p. 120.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_42" href="#FNanchor_42" class="label">[42]</a>
+Sidersky; Traité d’Analyse des Matières Sucrées, p. 97.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_43" href="#FNanchor_43" class="label">[43]</a>
+Manual of Sugar Analysis, pp. 143 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_44" href="#FNanchor_44" class="label">[44]</a>
+Landolt und Börnstein, Physikalisch-Chemische Tabellen.
+S. 460.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_45" href="#FNanchor_45" class="label">[45]</a>
+Bulletin No. 31. Department of Agriculture, Division of Chemistry, p. 232.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_46" href="#FNanchor_46" class="label">[46]</a>
+Zeitschrift des Vereins für die Rübenzucker-Industrie. 1870, S. 223.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_47" href="#FNanchor_47" class="label">[47]</a>
+Tucker’s Manual of Sugar Analysis, p. 164.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_48" href="#FNanchor_48" class="label">[48]</a>
+(bis). Gerlach, Spencer’s Handbook for Sugar Manufacturers, p. 91.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_49" href="#FNanchor_49" class="label">[49]</a>
+Vid. op. cit. supra, p. 45.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_50" href="#FNanchor_50" class="label">[50]</a>
+Vid. loc. et op. cit. supra.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_51" href="#FNanchor_51" class="label">[51]</a>
+Gill; Journal of the Chemical Society, Vol. 24, 1871, p. 91.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_52" href="#FNanchor_52" class="label">[52]</a>
+Wiley; American Chemical Journal, Vol. 6, p. 289.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_53" href="#FNanchor_53" class="label">[53]</a>
+Vid. op. cit. supra, p. 301.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_54" href="#FNanchor_54" class="label">[54]</a>
+Zeitschrift des Vereins für die Rübenzucker-Industrie, 1890. S. 876.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_55" href="#FNanchor_55" class="label">[55]</a>
+Weber and McPherson; Journal of the American Chemical Society. Vol.
+17, p. 320; Bulletin No. 43. Department of Agriculture, Division of
+Chemistry, p. 126.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_56" href="#FNanchor_56" class="label">[56]</a>
+Zeitschrift des Vereins für die Rübenzucker-Industrie, 1888, S. 51.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_57" href="#FNanchor_57" class="label">[57]</a>
+Vid. op. cit. supra, Ss, 699 und 763; 1890. S. 217.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_58" href="#FNanchor_58" class="label">[58]</a>
+Bulletin de l’Association des Chimistes de Sucrerie et
+de Distillerie, May, 1890, p. 431.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_59" href="#FNanchor_59" class="label">[59]</a>
+Neue Zeitschrift für Rübenzucker-Industrie, Band 19, S. 71.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_60" href="#FNanchor_60" class="label">[60]</a>
+Journal of the Chemical Society, Transactions, Vol. 57, pp. 834, et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_61" href="#FNanchor_61" class="label">[61]</a>
+Op. cit. supra, p. 866.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_62" href="#FNanchor_62" class="label">[62]</a>
+Op. cit. supra, 1891, p. 46.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_63" href="#FNanchor_63" class="label">[63]</a>
+Neue Zeitschrift für Rübenzucker-Industrie, Band 19, S. 71.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_64" href="#FNanchor_64" class="label">[64]</a>
+From γῦρος and δῦνᾶτός (δύνᾶμις).</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_65" href="#FNanchor_65" class="label">[65]</a>
+Landolt’s Handbook of the Polariscope, p. 125.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_66" href="#FNanchor_66" class="label">[66]</a>
+Vid. op. cit. supra, pp. 48 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_67" href="#FNanchor_67" class="label">[67]</a>
+Berichte der deutschen chemischen Gesellschaft, 1877, S. 1403.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_68" href="#FNanchor_68" class="label">[68]</a>
+Die landwirtschaftlichen Versuchs-Stationen, Band 40, S. 307.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_69" href="#FNanchor_69" class="label">[69]</a>
+Spencer’s Handbook for Sugar Manufacturers, p. 80; Landolt’s Handbook
+of the Polariscope, p. 216; Tollens’ Handbuch der Kohlenhydrate.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_224"></a>[Pg 224]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_70" href="#FNanchor_70" class="label">[70]</a>
+Annalen der Chemie and Pharmacie, May, 1870.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_71" href="#FNanchor_71" class="label">[71]</a>
+Tucker’s Manual of Sugar Analysis, p. 208.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_72" href="#FNanchor_72" class="label">[72]</a>
+Rapport fait a la Société d’Encouragement d’Agriculture;
+Journal de Pharmacie et de Chimie, 1844. 3d serie, Tome 6, p. 301.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_73" href="#FNanchor_73" class="label">[73]</a>
+Annalen der Chemie und Pharmacie, Band 39, S. 361.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_74" href="#FNanchor_74" class="label">[74]</a>
+Jahrbücher für praktische Heilkunde, 1845, S. 509.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_75" href="#FNanchor_75" class="label">[75]</a>
+Archives für Physiologische Heilkunde, 1848, Band 7, S 64.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_76" href="#FNanchor_76" class="label">[76]</a>
+Rodewald and Tollens; Berichte der deutschen chemischen
+Gesellschaft, Band 11, S. 2076.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_77" href="#FNanchor_77" class="label">[77]</a>
+Chemical News, Vol. 39, p. 77.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_78" href="#FNanchor_78" class="label">[78]</a>
+The Analyst, Vol. 19, p. 181.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_79" href="#FNanchor_79" class="label">[79]</a>
+Gaud; Bulletin de l’Association des Chimistes de Sucrerie et de Distillerie,
+Apr. 1895, p. 629; Comptes rendus, 1894, Tome 119, p. 604.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_80" href="#FNanchor_80" class="label">[80]</a>
+Annalen der Chemie und Pharmacie, B. 72, S. 106.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_81" href="#FNanchor_81" class="label">[81]</a>
+Journal of Analytical and Applied Chemistry, Vol. 4, p. 370.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_82" href="#FNanchor_82" class="label">[82]</a>
+Wiley; Bulletin de l’Association des Chimistes de
+Sucrerie et de Distillerie, April, 1884.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_83" href="#FNanchor_83" class="label">[83]</a>
+Vid. op. cit. supra, 1895, p. 642; Comptes rendus, Tome 119,
+1894, p. 650.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_84" href="#FNanchor_84" class="label">[84]</a>
+Annual Report, United States Department of Agriculture, 1879,
+p. 65; Zeitschrift für Analytische Chemie, Band 12, S. 296;
+Mohr Titrirmethode, sechste auflage, S. 508.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_85" href="#FNanchor_85" class="label">[85]</a>
+Comptes rendus, 1894, Tome 119, p. 478.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_86" href="#FNanchor_86" class="label">[86]</a>
+Gazetta Chimica Italiana, Tome 6, p. 322.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_87" href="#FNanchor_87" class="label">[87]</a>
+Sidersky; Traité d’Analyse des Matières Sucrées, p. 148.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_88" href="#FNanchor_88" class="label">[88]</a>
+Vid. op. cit. supra, p. 149.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_89" href="#FNanchor_89" class="label">[89]</a>
+Neue Zeitschrift für die Rübenzucker-Industrie, Band 22, S. 220.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_90" href="#FNanchor_90" class="label">[90]</a>
+Zeitschrift des Vereins für Rübenzucker-Industrie, 1889, S. 933.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_91" href="#FNanchor_91" class="label">[91]</a>
+Vid. op. cit. supra, 1887, S. 147.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_92" href="#FNanchor_92" class="label">[92]</a>
+Berichte der deutschen chemischen Gesellschaft, Band 23, No. 14, S. 3003;
+Zeitschrift des Vereins für die Rübenzucker-Industrie, 1891, S. 97.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_93" href="#FNanchor_93" class="label">[93]</a>
+Ost; vid. op. et loc. cit. supra.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_94" href="#FNanchor_94" class="label">[94]</a>
+Zeitschrift des Vereins für die Rübenzucker-Industrie, 1890, S. 187.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_95" href="#FNanchor_95" class="label">[95]</a>
+Chemical News, Vol. 39, p. 77.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_96" href="#FNanchor_96" class="label">[96]</a>
+The Analyst, 1894, p. 181.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_97" href="#FNanchor_97" class="label">[97]</a>
+Chemical News, Vol. 71, p. 235.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_98" href="#FNanchor_98" class="label">[98]</a>
+Journal de Pharmacie et de Chimie, 1894, Tome 30, p. 305.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_99" href="#FNanchor_99" class="label">[99]</a>
+Pharmaceutical Journal, (3), 23, p. 208.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_100" href="#FNanchor_100" class="label">[100]</a>
+Vid. op. cit. supra, (3), 25, p. 913.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_101" href="#FNanchor_101" class="label">[101]</a>
+Sidersky; Bulletin de l’Association des Chimistes,
+Juillet, 1886 et Sept. 1888.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_102" href="#FNanchor_102" class="label">[102]</a>
+Bodenbender and Scheller; Zeitschrift des Vereins für die
+Rübenzucker-Industrie, 1887, S. 138.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_225"></a>[Pg 225]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_103" href="#FNanchor_103" class="label">[103]</a>
+Vid. op. cit. supra, 1889, S. 935.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_104" href="#FNanchor_104" class="label">[104]</a>
+Ewell; Manuscript communication to author.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_105" href="#FNanchor_105" class="label">[105]</a>
+Journal für praktische Chemie, 1880, Band 22, 46; Handbuch der
+Spiritusfabrication, 1890, S. 79; Zeitschrift des Vereins für die
+Rübenzucker-Industrie, 1879, S. 1050; <i>Ibid</i>, 1883, S. 769;
+<i>Ibid</i>, 1889, S. 734.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_106" href="#FNanchor_106" class="label">[106]</a>
+Handbuch der Spiritusfabrication, 1890, 79.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_107" href="#FNanchor_107" class="label">[107]</a>
+Wein; Tabellen zur quantitativen Bestimmung der Zuckerarten, S. 13.
+(The caption for the table on page 159 should read as on page 160.)</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_108" href="#FNanchor_108" class="label">[108]</a>
+Zeitschrift des Vereins für die Rübenzucker-Industrie,
+1889, S. 735.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_109" href="#FNanchor_109" class="label">[109]</a>
+Bulletin No. 43, Department of Agriculture, Division of Chemistry, p. 209.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_110" href="#FNanchor_110" class="label">[110]</a>
+Chemiker-Zeitung, 1893, S. 548.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_111" href="#FNanchor_111" class="label">[111]</a>
+Wein; Tabellen zur quantitativen Bestimmung der Zuckerarten, S. 35.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_112" href="#FNanchor_112" class="label">[112]</a>
+Berichte der deutschen chemischen Gesellschaft, Band 16, S. 661.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_113" href="#FNanchor_113" class="label">[113]</a>
+Vid. op. cit. supra, Band 22, S. 87.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_114" href="#FNanchor_114" class="label">[114]</a>
+Chemisches Centralblatt, 1895, Band 2, S. 66.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_115" href="#FNanchor_115" class="label">[115]</a>
+Comptes rendus; Tome 112, No. 15, p. 799.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_116" href="#FNanchor_116" class="label">[116]</a>
+Vid. op. cit. supra, Tome 94, p. 1517.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_117" href="#FNanchor_117" class="label">[117]</a>
+Journal of the Chemical Society, June, 1888, p. 610. (In the formulas
+for lactose and arabinose read H₂₂ and H₁₀ respectively.)</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_118" href="#FNanchor_118" class="label">[118]</a>
+American Chemical Journal, Vol. 11, No. 7, p. 469.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_119" href="#FNanchor_119" class="label">[119]</a>
+Chemisches Centralblatt, 1889, No. 7.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_120" href="#FNanchor_120" class="label">[120]</a>
+American Chemical Journal, Vol. 17, No. 7, pp. 507, 517.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_121" href="#FNanchor_121" class="label">[121]</a>
+Comptes rendus, Tome 118, p. 426.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_122" href="#FNanchor_122" class="label">[122]</a>
+Justus Liebig’s Annalen der Chemie, 1890. Band 257, S. 160.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_123" href="#FNanchor_123" class="label">[123]</a>
+Journal of Analytical and Applied Chemistry, Vol. 7, pp. 68 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_124" href="#FNanchor_124" class="label">[124]</a>
+Flint and Tollens; Berichte der deutschen chemischen Gesellschaft,
+Band 25, S. 2912.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_125" href="#FNanchor_125" class="label">[125]</a>
+Vid. op. cit. supra, Band 23, S. 1751. (Read Günther.)</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_126" href="#FNanchor_126" class="label">[126]</a>
+Journal of Analytical and Applied Chemistry, Vol. 5, p. 421.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_127" href="#FNanchor_127" class="label">[127]</a>
+Vid. op. cit. supra, p. 426.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_128" href="#FNanchor_128" class="label">[128]</a>
+Berichte der deutschen chemischen Gesellschaft, Band 24, S. 3575.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_129" href="#FNanchor_129" class="label">[129]</a>
+Journal of Analytical and Applied Chemistry, Vol. 7, p. 74.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_130" href="#FNanchor_130" class="label">[130]</a>
+Chemiker-Zeitung, Band 17, 1743.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_131" href="#FNanchor_131" class="label">[131]</a>
+Vid. op. cit. supra, Band 18, N. 51, S. 966.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_132" href="#FNanchor_132" class="label">[132]</a>
+Monatshefte für Chemie, Band 16, S. 283; Berichte der
+deutschen chemischen Gesellschaft, Referate Band 28, S. 629.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_133" href="#FNanchor_133" class="label">[133]</a>
+Papasogli; Bulletin de l’Association des Chimistes de
+Sucrerie et de Distillerie, Juillet 1895, p. 68.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_134" href="#FNanchor_134" class="label">[134]</a>
+Gans und Tollens; Zeitschrift des Vereins für die
+Rübenzucker-Industrie, Band 38, S. 1126.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_135" href="#FNanchor_135" class="label">[135]</a>
+Berichte der deutschen chemischen Gesellschaft, 20, S. 181;
+Zeitschrift des Vereins für die Rübenzucker-Industrie, 1891, S. 895.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_226"></a>[Pg 226]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_136" href="#FNanchor_136" class="label">[136]</a>
+Zeitschrift des Vereins für die Rübenzucker-Industrie, 1891, S. 891.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_137" href="#FNanchor_137" class="label">[137]</a>
+Chemiker-Zeitung, 1888, No. 2; Zeitschrift des Vereins
+für die Rübenzucker-Industrie, 1888, S. 347.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_138" href="#FNanchor_138" class="label">[138]</a>
+Fischer; Berichte der deutschen chemischen Gesellschaft,
+Band 20, S. 821; Band 21, Ss. 988; 2631.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_139" href="#FNanchor_139" class="label">[139]</a>
+Zeitschrift für physiologische Chemie, Band 11, S. 492.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_140" href="#FNanchor_140" class="label">[140]</a>
+Vid. op. cit. supra, Band 12, No. 4, Ss. 355 et seq; No. 5,
+Ss. 377 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_141" href="#FNanchor_141" class="label">[141]</a>
+Berichte der deutschen chemischen Gesellschaft, Band 20, S. 540.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_142" href="#FNanchor_142" class="label">[142]</a>
+Sitzungsberichte der Mathematisch-Naturwissenschaften in Wien,
+Band 93, Heft 2, S. 912.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_143" href="#FNanchor_143" class="label">[143]</a>
+Tollens; Handbuch der Kohlenhydrate; von Lippmann, Chemie der Zuckerarten.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_144" href="#FNanchor_144" class="label">[144]</a>
+Wilder Quarter-Century Book, 1893; Abdruck aus dem Centralblatt für
+Bakteriologie und Parasitenkunde, Band 18, 1895, No. 1; American
+Journal of Medical Sciences, Sept., 1895.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_145" href="#FNanchor_145" class="label">[145]</a>
+Griffiths, Principal Starches used as Food; Nägeli’s
+Beiträge zur näheren Kenntniss der Stärkegruppe.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_146" href="#FNanchor_146" class="label">[146]</a>
+Zeitschrift für Physiologische Chemie, Band 12, Ss. 75-78.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_147" href="#FNanchor_147" class="label">[147]</a>
+Maercker; Handbuch der Spiritusfabrikation, 1890, S. 90.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_148" href="#FNanchor_148" class="label">[148]</a>
+Chemiker-Zeitung, Band 19, S. 1501.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_149" href="#FNanchor_149" class="label">[149]</a>
+Paragraphs <b><a href="#P_28">28-32</a></b>, this volume.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_150" href="#FNanchor_150" class="label">[150]</a>
+Vol. 2, p. 204.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_151" href="#FNanchor_151" class="label">[151]</a>
+Chemisches Centralblatt, 1877, Band 8, S. 732.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_152" href="#FNanchor_152" class="label">[152]</a>
+Chemiker-Zeitung, Band 19, S. 1501.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_153" href="#FNanchor_153" class="label">[153]</a>
+Vid. op. cit. supra, S. 1502; Moniteur Scientifique, 1887, p. 538.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_154" href="#FNanchor_154" class="label">[154]</a>
+Chemiker-Zeitung, Band 19, S. 1502.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_155" href="#FNanchor_155" class="label">[155]</a>
+Vid. op. cit. supra, 1895, S. 1727.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_156" href="#FNanchor_156" class="label">[156]</a>
+Chemiker-Zeitung, Band 19, S. 1502.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_157" href="#FNanchor_157" class="label">[157]</a>
+Jahresberichte der Agrikulturchemie, 1892, S. 664.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_158" href="#FNanchor_158" class="label">[158]</a>
+Journal de Pharmacie et de Chimie, 5ᵉ, Série, Tome 25, p. 394.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_159" href="#FNanchor_159" class="label">[159]</a>
+Journal of the American Chemical Society, Vol. 17, p. 64.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_160" href="#FNanchor_160" class="label">[160]</a>
+Repertorium der Analytischen Chemie, 1887, S. 299.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_161" href="#FNanchor_161" class="label">[161]</a>
+Journal of the American Chemical Society, Vol. 16, p. 726.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_162" href="#FNanchor_162" class="label">[162]</a>
+Förschungs Berichte über Lebensmittel, Hamburg; Abs.,
+The Analyst, Vol. 20, p. 210.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_163" href="#FNanchor_163" class="label">[163]</a>
+Rouvier; Comptes rendus, Tome 107, pp. 272, 278; Tome 111,
+pp. 64, 186; Tome 120, p. 1179.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_164" href="#FNanchor_164" class="label">[164]</a>
+Bulletin 13, Department of Agriculture, Division of Chemistry,
+pp. 154 et. seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_165" href="#FNanchor_165" class="label">[165]</a>
+Foods, Their Composition and Analysis, p. 139.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_166" href="#FNanchor_166" class="label">[166]</a>
+Richardson, Vid. op. cit. 142, p. 158.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_167" href="#FNanchor_167" class="label">[167]</a>
+Principal Starches used as Food, Cirencester, Baily &amp; Son,
+Market Place.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_168" href="#FNanchor_168" class="label">[168]</a>
+Vid. op. cit. 142, pp. 158 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_169" href="#FNanchor_169" class="label">[169]</a>
+Bulletin 44, Department of Agriculture, Division of Chemistry, p. 14.</p>
+</div>
+</div>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum"><a id="Page_227"></a>[Pg 227]</span></p>
+<h2 class="nobreak">PART THIRD.<br>
+<span class="h_subtitle">PROCESSES FOR DETECTING AND DETERMINING SUGARS<br>
+AND STARCHES AND OTHER CARBOHYDRATES IN CRUDE<br>
+OR MANUFACTURED AGRICULTURAL PRODUCTS.</span></h2>
+</div>
+
+<p id="P_203"><b>203. Introduction.</b>—In the preceding part directions have been
+given for the estimation of sugars and starches in approximately
+pure forms. In the present part will be described the most approved
+methods of separating these bodies and other carbohydrates from crude
+agricultural products and for their chemical examination. In many
+respects the processes which in a small way are used for preparing
+samples for analysis are employed on a large scale for technical and
+manufacturing purposes. It is evident, however, that the following
+paragraphs must be confined strictly to the analytical side of the
+question inasmuch as anything more than mere references to technical
+processes would lead into wide digressions.</p>
+
+<p>In the case of sugars the analyst is for the most part quite as much in
+need of reliable methods of extraction and preparation as of processes
+for analysis. With starches the matter is more simple and the chief
+methods of separating them for examination were necessarily described
+in the previous part.</p>
+
+<p>Sugars in fresh plants exist almost entirely in solution. This is
+true of all the great sources of the sugar of commerce, <i>viz.</i>,
+the palm, the maple, the sugar beet and sugar cane. This statement is
+also true of fruits and the natural nectar of flowers. By natural or
+artificial drying the sugar may be reduced to the solid or semisolid
+state as in the cases of raisins and honey. In certain seeds, deficient
+in water, sugars may possibly exist in a solid state naturally, as may
+be the case with sucrose in the peanut and raffinose in cotton seed.
+<span class="pagenum"><a id="Page_228"></a>[Pg 228]</span></p>
+
+<p>Starches on the other hand when soluble, are probably not true
+starches, but they partake more or less of a dextrinoid nature. Fine
+starch particles occur abundantly in the juices of some plants,
+as for instance sorghum, where they are associated with sugar and
+can be obtained from the expressed juice by subsidence. But even
+in such a case it is not certain that the starch enters into the
+general circulation. It is more likely formed locally by biochemical
+condensation of its constituents. Starches in a soluble or semisoluble
+state are transported, as a rule, to the tubers or seeds of plants
+where they are accumulated in large quantities as a reserve food for
+future growth. For a study of the plant metabolism whereby starch is
+produced and for its histological and physiological properties the
+reader may consult the standard authorities on vegetable physiology.<a id="FNanchor_170" href="#Footnote_170" class="fnanchor">[170]</a></p>
+
+<p><b>204. Sugar in the Sap of Trees.</b>—Many trees at certain seasons
+of the year, carry large quantities of sugar in their sap. Among these
+the maple and sugar palm are preeminent. The sap is secured by cutting
+a pocket into the side of the tree or by boring into it and allowing
+the sap to run into an appropriate receptacle through a spile. The
+content of sugar in the sap of the maple and palm varies greatly. In
+some cases it falls as low as one and a half and in others rises to as
+much as six or seven per cent.<a id="FNanchor_171" href="#Footnote_171" class="fnanchor">[171]</a>
+In most cases the sugar in the maple sap is pure sucrose, but towards
+the end of the flowing season it may undergo changes of a viscous
+nature due to fermentation, or inversion, forming traces of invert
+sugar. In this country the sap of the maple may flow freely on any warm
+day in winter, but the sugar season proper begins about February 15th
+in Southern Ohio and Indiana, and about March 25th in Vermont. It lasts
+from six weeks to two months. The sap flows best during moderately
+warm, still days, after a light freeze.</p>
+
+<p>In addition to sugar the maple sap contains a trace of albuminoid
+matters and some malic acid combined with lime. As a rule it can be
+subjected to polarization without preliminary clarification.</p>
+
+<p><b>205. Determination of Sugar in Saps.</b>—In most cases the sap may
+be directly polarized in a 200 millimeter tube. Its specific gravity is
+<span class="pagenum"><a id="Page_229"></a>[Pg 229]</span>
+obtained by a spindle or pyknometer, and the percentage of sugars taken
+directly from the table on <a href="#P_58">page 73</a>, the degree brix
+corresponding to the sugar percentage.</p>
+
+<p>On polarizing, the sugar percentage is calculated as follows:</p>
+
+<p>Multiply the specific gravity of the sap by 100 and divide the product
+by 26.048. Divide the direct reading of the sap on the sugar scale by
+the quotient obtained above, and the quotient thus obtained will be the
+correct percentage of sugar in the original solution.</p>
+
+<p>The formula is applicable for those instruments in which 26.048 grams
+represent the normal quantity of sugar which in 100 cubic centimeters
+reads 100 divisions on the scale. When other factors are used they
+should be substituted for 26.048 in the above formula.</p>
+
+<p>The principle of the calculation is based on the weight of the sap
+which is contained in 100 cubic centimeters, and this is evidently
+obtained by multiplying 100 by the specific gravity of the sap. Since
+26.048 is the normal quantity of sugar in that volume of the solution
+the quotient of the actual weight divided by that factor shows how many
+times too great the observed polarization is. The simple division of
+the polariscope reading by this factor gives the correct reading.</p>
+
+<p><i>Example</i>: Let the specific gravity of the sap be 1.015 and the
+observed polarization be 15.0. Then the true percentage of sugar in the
+sap is found by the equation:</p>
+
+<p class="f105">101.5 : 26.048 = 15.0 : <i>x</i>.</p>
+
+<p class="center">Whence <i>x</i> = 3.85 = percentage of sugar in the sap.</p>
+
+<p>The process outlined above is not applicable when a clarifying reagent
+such as lead subacetate or alumina cream must be used. But even in
+these cases it will not be found necessary to weigh the sap. A sugar
+flask graduated at 100 and 110 cubic centimeters is used and filled to
+the first mark with the sap, the specific gravity of which is known.
+The clarifying reagent is added, the volume completed to the second
+mark with water, and the contents of the flask well shaken and thrown
+on a dry filter. The observation tube, which should be 220 millimeters
+in length, is then filled with the clear filtrate and the rest of the
+process is as described above. A 200 millimeter tube may also be used in
+<span class="pagenum"><a id="Page_230"></a>[Pg 230]</span>
+this case and the observed reading increased by one-tenth.</p>
+
+<div class="figcontainer smcap">
+  <div class="figsub">
+   <img id="FIG_62" src="images/fig62.jpg" alt="" width="350" height="438" >
+   <p class="center">&nbsp;<br>Fig. 62.<br> Laboratory Cane Mill.</p>
+  </div>
+  <div id="FIG_63" class="figsub">
+   <img src="images/fig63.jpg" alt="" width="150" height="476" >
+   <p class="center">Fig. 63.<br> Weighing<br> Pipette.</p>
+   </div>
+</div>
+
+<p><b>206. Estimation of Sugar in the Sap of Sugar Cane and
+Sorghum.</b>—In bodies like sugar cane and sorghum the sap containing
+the sugar will not flow as in the cases of the maple and sugar palm.
+The simplest way of securing the sap of the bodies named is to subject
+them to pressure between rolls. A convenient method of obtaining the
+sap or juice is by passing the cane through a small three-roll mill
+indicated in the <a href="#FIG_62">figure</a>. Small mills of this
+kind have been used in this division for many years and with entire
+satisfaction. Small canes, such as sorghum, may be milled one at a
+time, or even two or three when they are very small. In the case of
+large canes, it is necessary that they be split and only half of them
+used at once. The mill should not be crowded by the feed in such a way
+as to endanger it or make it too difficult for the laborer to turn.
+From fifty to sixty per cent of the weight of a cane in juice may be
+obtained by passing it through one of these small mills. Experience
+has shown that there is a little difference between the juice as first
+expressed and the residual sap remaining in the bagasse, but the juice
+first expressed may be used for analysis for control purposes as a fair
+representative of all that the cane contains.</p>
+
+<p>To determine the percentage of juice expressed, the canes may be
+weighed before passing through the mill and the juice collected. Its
+weight divided by the weight of the original cane will give the per
+cent of the juice expressed, calculated on the whole cane. Instead of
+weighing the juice the bagasse may also be collected and weighed; but
+on account of the rapidity with which it dries the operation should be
+<span class="pagenum"><a id="Page_231"></a>[Pg 231]</span>
+accomplished without delay. The expressed juice is clarified with lead
+subacetate, filtered and polarized in the manner described in former
+paragraphs. Instead of weighing the juice, its specific gravity may
+be taken by an accurate spindle and the volume of it, equivalent to a
+given weight, measured from a sucrose pipette.<a id="FNanchor_172" href="#Footnote_172" class="fnanchor">[172]</a></p>
+
+<p>A sucrose pipette for cane juice has a graduation on the upper part
+of the stem which enables the operator to deliver double the normal
+weight for the polariscope used, after having determined the density of
+the juice by means of a spindle. A graduation of from 5° to 25° of the
+brix spindle will be sufficient for all variations in the density of
+the juice, or one covering a range of from 10° to 20° will suffice for
+most instances. The greater the density of the juice the less volume
+of it will be required for the weight mentioned. For general use, the
+sucrose pipette is graduated on the stem to deliver from forty-eight
+to 50.5 cubic centimeters, the graduations being in terms of the brix
+spindle. The graduation of the stem of this instrument is shown in the
+accompanying <a href="#FIG_62">figure</a>. In the use of the pipette it
+is only necessary to fill it to the degree on the stem corresponding to
+the degree brix found in the preliminary trial.</p>
+
+<p>The quantities of juice corresponding to each degree and fractional
+degree of the brix spindle are given in the following table; calculated
+for the normal weight 26.048 grams for the ventzke and for 16.19 grams
+for the laurent scale. The measured quantities of juice are placed in
+a 100 cubic centimeter sugar flask, treated with the proper quantity
+of lead subacetate, the volume completed to the mark, and the juice
+filtered and polarized in a 200 millimeter tube. The reading of the
+polariscope is divided by two for the factor 26.048 and by three for
+the factor 16.19.
+<span class="pagenum"><a id="Page_232"></a>[Pg 232]</span></p>
+
+<p class="f120"><b><span class="smcap">Table for Use of Sucrose Pipettes.</span></b></p>
+
+
+<table class="spb1">
+   <thead><tr class="bt2">
+      <th class="tdc bb">&nbsp;Degrees&nbsp;<br>brix.</th>
+      <th class="tdc bb bl">&nbsp;Cubic centimeters&nbsp;<br>of juice for<br>26.048 factor.<br>
+                            Divide<br> reading by two.</th>
+      <th class="tdc bb bl2">&nbsp;Degrees&nbsp;<br>brix.</th>
+      <th class="tdc bb bl">&nbsp;Cubic centimeters&nbsp;<br>of juice for<br>16.19 factor.<br>
+                            Divide<br> reading by three.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">&#8199;5.0</td>
+      <td class="tdc bl">51.1</td>
+      <td class="tdc bl2">&#8199;5.0</td>
+      <td class="tdc bl">47.6</td>
+   </tr><tr>
+      <td class="tdc">&#8199;5.4</td>
+      <td class="tdc bl">51.0</td>
+      <td class="tdc bl2">&#8199;5.7</td>
+      <td class="tdc bl">47.5</td>
+   </tr><tr>
+      <td class="tdc">&#8199;5.7</td>
+      <td class="tdc bl">50.9</td>
+      <td class="tdc bl2">&#8199;6.3</td>
+      <td class="tdc bl">47.4</td>
+   </tr><tr>
+      <td class="tdc">&#8199;6.4</td>
+      <td class="tdc bl">50.8</td>
+      <td class="tdc bl2">&#8199;6.8</td>
+      <td class="tdc bl">47.3</td>
+   </tr><tr>
+      <td class="tdc">&#8199;6.9</td>
+      <td class="tdc bl">50.7</td>
+      <td class="tdc bl2">&#8199;7.3</td>
+      <td class="tdc bl">47.2</td>
+   </tr><tr>
+      <td class="tdc">&#8199;7.4</td>
+      <td class="tdc bl">50.6</td>
+      <td class="tdc bl2">&#8199;7.8</td>
+      <td class="tdc bl">47.1</td>
+   </tr><tr>
+      <td class="tdc">&#8199;7.9</td>
+      <td class="tdc bl">50.5</td>
+      <td class="tdc bl2">&#8199;8.3</td>
+      <td class="tdc bl">47.0</td>
+   </tr><tr>
+      <td class="tdc">&#8199;8.4</td>
+      <td class="tdc bl">50.4</td>
+      <td class="tdc bl2">&#8199;8.9</td>
+      <td class="tdc bl">46.9</td>
+   </tr><tr>
+      <td class="tdc">&#8199;8.9</td>
+      <td class="tdc bl">50.3</td>
+      <td class="tdc bl2">&#8199;9.5</td>
+      <td class="tdc bl">46.8</td>
+   </tr><tr>
+      <td class="tdc">&#8199;9.4</td>
+      <td class="tdc bl">50.2</td>
+      <td class="tdc bl2">10.0</td>
+      <td class="tdc bl">46.7</td>
+   </tr><tr class="bb">
+      <td class="tdc">&#8199;9.9</td>
+      <td class="tdc bl">50.1</td>
+      <td class="tdc bl2">10.5</td>
+      <td class="tdc bl">46.6</td>
+   </tr><tr>
+      <td class="tdc">10.4</td>
+      <td class="tdc bl">50.0</td>
+      <td class="tdc bl2">11.0</td>
+      <td class="tdc bl">46.5</td>
+   </tr><tr>
+      <td class="tdc">10.9</td>
+      <td class="tdc bl">49.9</td>
+      <td class="tdc bl2">11.6</td>
+      <td class="tdc bl">46.4</td>
+   </tr><tr>
+      <td class="tdc">11.4</td>
+      <td class="tdc bl">49.8</td>
+      <td class="tdc bl2">12.1</td>
+      <td class="tdc bl">46.3</td>
+   </tr><tr>
+      <td class="tdc">11.9</td>
+      <td class="tdc bl">49.7</td>
+      <td class="tdc bl2">12.7</td>
+      <td class="tdc bl">46.2</td>
+   </tr><tr>
+      <td class="tdc">12.4</td>
+      <td class="tdc bl">49.6</td>
+      <td class="tdc bl2">13.3</td>
+      <td class="tdc bl">46.1</td>
+   </tr><tr>
+      <td class="tdc">12.9</td>
+      <td class="tdc bl">49.5</td>
+      <td class="tdc bl2">13.8</td>
+      <td class="tdc bl">46.0</td>
+   </tr><tr>
+      <td class="tdc">13.4</td>
+      <td class="tdc bl">49.4</td>
+      <td class="tdc bl2">14.3</td>
+      <td class="tdc bl">45.9</td>
+   </tr><tr>
+      <td class="tdc">13.9</td>
+      <td class="tdc bl">49.3</td>
+      <td class="tdc bl2">14.8</td>
+      <td class="tdc bl">45.8</td>
+   </tr><tr>
+      <td class="tdc">14.4</td>
+      <td class="tdc bl">49.2</td>
+      <td class="tdc bl2">15.3</td>
+      <td class="tdc bl">45.7</td>
+   </tr><tr class="bb">
+      <td class="tdc">14.9</td>
+      <td class="tdc bl">49.1</td>
+      <td class="tdc bl2">15.9</td>
+      <td class="tdc bl">45.6</td>
+   </tr><tr>
+      <td class="tdc">15.4</td>
+      <td class="tdc bl">49.0</td>
+      <td class="tdc bl2">16.4</td>
+      <td class="tdc bl">45.5</td>
+   </tr><tr>
+      <td class="tdc">15.9</td>
+      <td class="tdc bl">48.9</td>
+      <td class="tdc bl2">17.0</td>
+      <td class="tdc bl">45.4</td>
+   </tr><tr>
+      <td class="tdc">16.4</td>
+      <td class="tdc bl">48.8</td>
+      <td class="tdc bl2">17.5</td>
+      <td class="tdc bl">45.3</td>
+   </tr><tr>
+      <td class="tdc">16.9</td>
+      <td class="tdc bl">48.7</td>
+      <td class="tdc bl2">18.0</td>
+      <td class="tdc bl">45.2</td>
+   </tr><tr>
+      <td class="tdc">17.4</td>
+      <td class="tdc bl">48.6</td>
+      <td class="tdc bl2">18.6</td>
+      <td class="tdc bl">45.1</td>
+   </tr><tr>
+      <td class="tdc">17.9</td>
+      <td class="tdc bl">48.5</td>
+      <td class="tdc bl2">19.1</td>
+      <td class="tdc bl">45.0</td>
+   </tr><tr>
+      <td class="tdc">18.4</td>
+      <td class="tdc bl">48.4</td>
+      <td class="tdc bl2">19.7</td>
+      <td class="tdc bl">44.9</td>
+   </tr><tr>
+      <td class="tdc">18.9</td>
+      <td class="tdc bl">48.3</td>
+      <td class="tdc bl2">20.2</td>
+      <td class="tdc bl">44.8</td>
+   </tr><tr>
+      <td class="tdc">19.4</td>
+      <td class="tdc bl">48.2</td>
+      <td class="tdc bl2">&nbsp;</td>
+      <td class="tdc bl">&nbsp;</td>
+   </tr><tr class="bb">
+      <td class="tdc">19.9</td>
+      <td class="tdc bl">48.1</td>
+      <td class="tdc bl2">&nbsp;</td>
+      <td class="tdc bl">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>In ordering sucrose pipettes the factor for which they are to be
+graduated should be stated.</p>
+
+<p>It is evident also that with the help of the foregoing table the
+measurements may be made by means of a burette. For instance, if the
+degree brix is found to be 19.9, 48.1 cubic centimeters are to be used.
+This quantity can be easily run from a burette. In order to make the
+pipette more convenient it has been customary in this laboratory, as
+practiced by Carr, to attach a glass tube with a stopcock by means of
+<span class="pagenum"><a id="Page_233"></a>[Pg 233]</span>
+a rubber tube to the upper part of the pipette, whereby the exact level
+of the juice in the stem of the pipette can be easily set at any
+required mark.</p>
+
+<p>In the polarization of dilute solutions, such as are found in the
+saps and juices referred to above, it must not be forgotten that the
+gyrodynat of the sucrose is increased as the density of the solution
+is diminished. This change introduces a slight error into the work
+which is of no consequence from a technical point of view, but
+becomes a matter which must be considered in exact determinations. To
+avoid the annoyance of calculating the gyrodynat for every degree of
+concentration, tables have been constructed by Schmitz and Crampton by
+means of which the actual percentage of sugar, corresponding to any
+degree of polarization, is determined by inspection. These tables may
+be used when extremely accurate work is required.<a id="FNanchor_173" href="#Footnote_173" class="fnanchor">[173]</a></p>
+
+<div class="figleft smcap">
+    <img id="FIG_64" src="images/fig64.jpg" alt="" width="200" height="389" >
+    <p class="center spb1">Figure 64. Gird’s<br> Gravimeter.</p>
+</div>
+
+<p><b>207. Measuring Sugar Juices with a Gravimeter.</b>—A convenient
+method of weighing sugar juices is the gravimetric process designed by
+Gird.<a id="FNanchor_174" href="#Footnote_174" class="fnanchor">[174]</a>
+The apparatus is fully illustrated by <a href="#FIG_64">Fig. 64</a>. The hydrometer
+F has a weight of 26.048 grams and its stem is also graduated in
+degrees brix. The juice is poured into the cylinder A and allowed to
+stand until air bubbles have escaped. In filling A the finger is held
+over the orifice G so that the siphon tube B is completely filled, the
+air escaping at the vent C. After the tube is filled the finger is
+withdrawn from G and all the liquid which will run out at G allowed to
+<span class="pagenum"><a id="Page_234"></a>[Pg 234]</span>
+escape. The sugar flask D is now brought under G and the hydrometer F
+allowed to descend into A. The hydrometer will displace exactly its
+own weight of liquid. For convenience of reading, the index E may be
+used which is set five degrees above the surface of the liquid in
+A. The number of degrees brix read by E is then diminished by five.
+The hydrometer has been improved since the description given by the
+addition of a thermometer which, in addition to carrying a graduation
+in degrees, also shows the correction to be made upon the degree brix
+for each degree read. It is evident that the hydrometer may be made of
+any weight, and thus the delivery of any desired amount of juice be secured.</p>
+
+<p><b>208. Determination of Reducing Bodies in Cane Juices.</b>—Sucrose
+in cane juices is constantly accompanied with reducing sugars, or other
+bodies which have a similar action on fehling liquor, which interfere
+to a considerable degree with the practical manufacture of sugar. It is
+important to determine with a moderate degree of accuracy the quantity
+of these bodies. These sugars or reducing bodies are of a peculiar
+nature. The author pointed out many years ago that these reducing
+bodies were without action on polarized light, and for this reason
+proposed the name anoptose as one characteristic of their nature.<a id="FNanchor_175" href="#Footnote_175" class="fnanchor">[175]</a>
+It is also found that these bodies do not yield theoretically the quantity
+of alcohol which a true sugar of the hexose type would give.<a id="FNanchor_176" href="#Footnote_176" class="fnanchor">[176]</a>
+It is entirely probable, therefore, that they are quite different in
+their nature from many of the commonly known sugars. On account of the
+difficulty of separating these bodies in a pure state their actual
+copper reducing power is not known. For practical purposes, however, it
+is assumed to be the same as that of dextrose or invert sugar and the
+percentage of these bodies present is calculated on that assumption.
+In the determination of these sugars or reducing bodies, the quantity
+weighed may be determined by an apparatus entirely similar to the
+sucrose pipette just described above. The quantity of juice used should
+be diluted as a rule to such a degree as not to contain more than one
+per cent of the reducing bodies. For the best work, the juices should
+be clarified with lead subacetate and the excess of lead removed with
+sodium carbonate. For technical control work in sugar factories, this
+<span class="pagenum"><a id="Page_235"></a>[Pg 235]</span>
+process may be omitted as in such cases rapidity of work is a matter
+of considerable importance and the approximate estimation of the total
+quantity of reducing bodies is all that is desired.</p>
+
+<p>For volumetric work, the solution of copper and the method of
+manipulation described in paragraph <b><a href="#P_117">117</a></b> are
+most conveniently used.</p>
+
+<p><b>209. Preservation of Sugar Juices for Analysis.</b>—Lead subacetate
+not only clarifies the juices of canes and thus permits of their more
+exact analytical examination, but also exercises preservative effects
+which enable it to be used as a preserving agent and thus greatly
+diminish the amount of work necessary in the technical control of a
+sugar factory. Instead, therefore, of the analyst being compelled to
+make an examination of every sample of the juice, aliquot portions
+representing the different quantities can be preserved and one analysis
+made for all. This method has been thoroughly investigated by Edson,
+who also finds that the errors, which may be introduced by the use of
+the lead subacetate in the analytical work, may be entirely avoided by
+using the normal lead acetate.<a id="FNanchor_177" href="#Footnote_177" class="fnanchor">[177]</a></p>
+
+<p>In the use of the normal lead acetate, much less acetic acid is
+required in the polariscopic work than when the subacetate is used.
+The normal lead acetate is not so good a clarifying agent as the
+subacetate, but its efficiency in this respect is increased by the
+addition of a little acetic acid. In its use, it is not necessary to
+remove the lead, even for the determination of the reducing bodies.</p>
+
+<p>For further details in regard to the technical determination of
+reducing bodies, special works may be consulted.<a id="FNanchor_178" href="#Footnote_178" class="fnanchor">[178]</a></p>
+
+<p><b>210. Direct Determination of Sugars in Canes.</b>—The methods,
+which have just been described, of securing the juices of cane by
+pressure and of determining the sugars therein, do not give the actual
+percentage of sugar in the cane. An approximate result may be secured
+by assuming that the cane is composed of ninety parts of juice and ten
+parts of cellular tissues and other insoluble matters. This assumption
+is approximately true in most cases, but there are often conditions
+arising which render the data calculated on the above assumption
+misleading. In any particular case in order to be certain that the
+<span class="pagenum"><a id="Page_236"></a>[Pg 236]</span>
+correct percentage of sugar is secured it will be necessary to
+determine the fiber in the cane. This is an analytical process of
+considerable labor and especially so on account of the difficulty of
+securing samples which represent the average composition of the cane.
+The fibrous structure of the canes, the hardness of their external
+covering and the toughness of their nodes or joints render the
+sampling extremely difficult. Moreover, the content of sugar varies
+in different parts of the cane. The parts nearest the ground are,
+as a rule, richer than the upper joints and this is especially true
+of sugar cane. In order, therefore, to get a fair sample, even of a
+single cane, all parts of it must be considered. Several methods of the
+direct determination of sugar in canes have been proposed and will be
+described below.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_65" src="images/fig65.jpg" alt="" width="500" height="487" >
+    <p class="center">Figure 65. Machine for Cutting Canes.</p>
+</div>
+
+<p><b>211. Methods of Cutting or Shredding the Cane for Analytical
+Purposes.</b>—A simple method of cutting canes into small pieces which
+will permit of an even sampling is very much to be desired. The cutting
+<span class="pagenum"><a id="Page_237"></a>[Pg 237]</span>
+apparatus shown in <a href="#FIG_65">Fig. 65</a> has been long in use in this
+laboratory. The canes by it are cut into thin slices, but the cutting edge of
+the knife being perpendicular to the length of the cane renders the use of the
+instrument somewhat laborious and unsatisfactory. A considerable time
+is required to cut a single cane and the slices which are formed should
+be received in a vessel which will protect them as much as possible
+from evaporation during the process of the work. Instead of the
+apparatus above a small cane cutting machine arranged with four knives
+on a revolving disk maybe used. The apparatus is shown in <a href="#FIG_66">Fig. 66</a>.
+The cane is fed against the knives through the hole shown in the open front
+of the apparatus and the knives thus strike the cane obliquely.<a id="FNanchor_179" href="#Footnote_179" class="fnanchor">[179]</a>
+The knives can be set in the revolving disk at any desired position so
+as to cut the canes into chips as fine as may be desired. The cossettes
+furnished by this method may be sampled directly for the extraction of
+the sugar. In the case of the cossettes from both instruments described
+above a finer subdivision may be secured by passing them through a
+sausage cutter.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_66" src="images/fig66.jpg" alt="" width="600" height="388" >
+    <p class="center">Figure 66. Cane Cutting Mill.</p>
+</div>
+
+<p>The best method for shredding canes, however, is to pass them through
+the apparatus described on <a href="#Page_9">page 9</a>. That machine
+gives an extremely fine, moist mass, which is of uniform nature and
+capable of being directly sampled.</p>
+
+<p><span class="pagenum"><a id="Page_238"></a>[Pg 238]</span>
+<b>212. Methods of Determination.</b>—Even the finely divided
+material obtained by the machine just described is not suited to give
+an instantaneous diffusion for polarization as is done by the finely
+ground beet pulp to be described further on. For the determination of
+sugar a proper weight of the cossettes or pulp obtained as described
+above, taken after thorough mixing, is placed in a flask graduated
+properly and treated with water.<a id="FNanchor_180" href="#Footnote_180" class="fnanchor">[180]</a></p>
+
+<p>The flask in which the mixture takes place should be marked to
+compensate for the volume of the fiber of the cane. When the normal
+weight of cane is taken for the ventzke scale, <i>viz.</i>, 26.048, the
+flask should be graduated at 102.6 cubic centimeters. If double the
+normal weight be taken, the flask should be graduated at 205.2 cubic
+centimeters. This graduation is based on the assumption of the presence
+of fiber amounting to ten per cent of the weight of the cossettes. The
+fiber is so nearly the density of the juice obtained as to be regarded
+as one gram equal to one cubic centimeter. The flask is at first filled
+almost full of water and then warmed to near the boiling point for an
+hour with frequent shaking. It is then filled to a little above the
+mark, the contents well mixed and warmed for ten minutes more with
+frequent shaking. After cooling, the volume is made up to the mark,
+well shaken and poured upon a filter. The filtrate is collected in a
+sugar flask marked at fifty and fifty-five cubic centimeters. When
+filled to the first mark a proper quantity of lead subacetate is added,
+the volume completed to the second mark with water, the contents of the
+flask well shaken, poured upon a filter and the filtrate polarized in
+the usual way.</p>
+
+<p>The reducing sugar is determined in an aliquot part of the filtrate by
+one of the alkaline copper methods.</p>
+
+<p><b>213. Determination by Drying and Extraction.</b>—Instead of the
+diffusion and polarization method just described, the fine pulp
+obtained may be dried, the dried residue ground in a drug mill and
+extracted with aqueous alcohol or with water.</p>
+
+<p>To facilitate the calculation when this method is employed, the water
+content of a small portion of the well sampled pulp is determined. The
+rest of the pulp is dried, first for a few hours at a temperature not
+<span class="pagenum"><a id="Page_239"></a>[Pg 239]</span>
+above 60° or 70°, and then at the temperature of boiling water, either
+in the open air or a partial vacuum, until all the water is driven off.
+The dried residue can then be preserved in well stoppered bottles for
+the determination of sugar at any convenient period. The finely ground
+dried residue for this purpose is placed in an extraction apparatus
+and thoroughly exhausted with eighty per cent alcohol. The extract is
+dried and weighed, giving the total weight of all sugars present. After
+weighing, the extract is dissolved in water, made up to a definite
+volume and the reducing sugars determined in an aliquot portion thereof
+by the usual methods. The weight of reducing sugars found, calculated
+for the whole extract deducted from the total weight of this extract
+will give the weight of the sucrose in the sample. From this number the
+content of sugar in the original cane is determined from the percentage
+of water found in the original sample.</p>
+
+<p><i>Example.</i>—In a sample of finely pulped canes the content of
+water is found to be 76.5 per cent. The thoroughly dried pulp is ground
+and extracted with aqueous alcohol. Five grams give two and five-tenths
+grams of the extract. The extract is dissolved in water, made up to
+a definite volume and the reducing sugars determined in an aliquot
+part and calculated for the whole, amounting to 150 milligrams. The
+extract is therefore composed of 2.35 grams of sucrose and 0.15 gram
+of reducing sugars. The calculation is now made to the original sample
+which contained 76.5 per cent of water and 23.5 per cent of dry matter,
+as follows:</p>
+
+<p class="f105">5 : <i>x</i> :: 23.5 : 100, whence <i>x</i> = 21.27,</p>
+
+<p>the weight of the original material corresponding to five grams of the
+dry substance. The original composition of the sample is therefore
+expressed by the following numbers:</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdr">Per cent.</td>
+   </tr><tr>
+      <td class="tdl">Sucrose</td>
+      <td class="tdr_wsp">11.1</td>
+   </tr><tr>
+      <td class="tdl">Reducing sugars</td>
+      <td class="tdr_wsp">0.7</td>
+   </tr><tr>
+      <td class="tdl">Water</td>
+      <td class="tdr_wsp">76.5</td>
+   </tr><tr>
+      <td class="tdl">Fiber (insoluble matter)</td>
+      <td class="tdr_wsp">11.7</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>214. Examination of the Bagasse.</b>—The method just described for
+<span class="pagenum"><a id="Page_240"></a>[Pg 240]</span>
+the examination of canes may be also applied to the analysis of
+bagasses, with the changes made necessary by the increased percentage
+of fiber therein. On account of the large surface exposed by the
+bagasse, the sampling, shredding and weighing should be accomplished as
+speedily as possible to avoid loss of moisture.</p>
+
+<p>The optical examination of bagasses is rendered difficult by reason of
+the uneven pressure to which the canes are subjected. With fairly good
+milling in technical work the bagasses will have at least thirty per
+cent of fiber. The method for the polariscopic examination is therefore
+based upon that assumption, but the volume of the solution must be
+changed for varying percentages of fiber in the bagasse. On account of
+the smaller percentage of sugar, it is convenient to take double or
+three times the normal weight of the bagasse for examination. Since
+large sugar flasks are not commonly to be had the diffusion of the
+bagasse may be conducted in a quarter liter flask. In a quarter liter
+flask place 52.096 grams of the finely shredded bagasse, very nearly
+fill the flask with water and extract the sugar as described for canes
+in the foregoing paragraphs. In the weight of bagasse used there will
+be, in round numbers, fifteen grams of fiber. When the volume of water
+is completed to the mark the actual content of liquid in the flask will
+therefore be only 235 cubic centimeters. Fifty cubic centimeters of the
+filtrate are placed in a sugar flask marked at fifty and fifty-five
+cubic centimeters, the proper quantity of lead subacetate solution
+added, the volume completed to the upper mark, the contents of the
+flask well shaken, filtered and polarized in a 200 millimeter tube. Let
+the reading obtained be four degrees and increase this by one-tenth for
+the increased volume of solution above fifty cubic centimeters. The
+true reading is therefore four degrees and four-tenths. This reading,
+however, must be corrected, because the original volume instead of
+being 200 cubic centimeters, is 235 cubic centimeters. The actual
+percentage of sugar in the sample examined is obtained by the following
+proportion:</p>
+
+<p class="f105">200 : 235 = 4.4 : <i>x</i>.</p>
+
+<p>The correct reading is therefore 5°.2, the percentage of sugar in the
+sample examined.
+<span class="pagenum"><a id="Page_241"></a>[Pg 241]</span></p>
+
+<p>The results obtained by the method just described may vary somewhat
+from the true percentage by reason of the variation of the content
+of fiber in the bagasse. It is, however, sufficiently accurate for
+technical control in sugar factories and on account of its rapidity
+of execution is to be preferred for this purpose. More accurate
+results would be obtained by drying the bagasse, and proceeding with
+the examination in a manner entirely analogous to that described for
+the extraction of sugar from dried canes by aqueous alcohol. In both
+instances the reducing sugar is determined in the manner already
+mentioned.</p>
+
+<p><b>215. Determination of Fiber in Cane.</b>—In estimating the content
+of sugar in canes by the analysis of the expressed juices, it is
+important to make frequent determinations of the fiber for the purpose
+of obtaining correct data for calculation. In periods of excessive
+drought, or when the canes are quite mature, the relative content of
+fiber is increased, while, on the other hand, in case of immature
+canes, or during excessive rainfalls, it is diminished. The chief
+difficulty in determining the content of fiber in canes is found in
+securing a representative sample. On account of the hard and fibrous
+nature of the envelope and of their nodular tissues, canes are reduced
+to a fine pulp with great difficulty by the apparatus in ordinary
+use. A fairly homogeneous pulp, however, may be obtained by means of
+the shredder described on <a href="#Page_9">page 9</a>. The canes having been
+shredded as finely as possible, a weighed quantity is placed in any convenient
+extraction apparatus and thoroughly exhausted with hot water. The
+treatment with hot water should be continued until a few drops of the
+extract evaporated on a watch glass will leave no sensible residue.
+The residual fiber is dried to constant weight at the temperature of
+boiling water, cooled in a desiccator and rapidly weighed and the
+percentage of fiber calculated from the data obtained. On account of
+the great difficulty of securing a homogeneous pulp, even with the best
+shredding machines, the determination should be made in duplicate or
+triplicate and the mean of the results entered as the percentage of
+fiber. The term fiber as used in this sense, must not be confounded
+with the same term employed in the analysis of fodders and feeding
+<span class="pagenum"><a id="Page_242"></a>[Pg 242]</span>
+stuffs. In the latter case the term is applied to the residue left
+after the successive treatment of the material with boiling, dilute
+acid and alkali. The analysis of canes for feeding purposes is
+conducted in the general manner hereinafter described for fodders.</p>
+
+<p><b>216. Estimation of Sugar in Sugar Beets.</b>—The methods employed
+for the determination of the sugar content of beets are analogous to
+those used for canes, with such variations in the method of extraction
+as are made possible and necessary by the difference in the nature
+of these sacchariferous plants. The sugar beet is more free of fiber
+and the hard and knotty substances composing the joints of plants
+are entirely absent from their composition. For this reason they
+are readily reduced to a fine pulp, from which the sugar is easily
+extracted. The analytical processes are also greatly simplified by the
+complete absence of reducing sugars from the juices of healthy beets.
+The only sugar aside from sucrose which is present in these juices
+is raffinose, and this is not found in healthy beets, except when
+they have been injured by frost or long keeping. In practical work,
+therefore, the determination of sucrose completes the analysis in so
+far as sugars are concerned. Four methods of procedure will illustrate
+all the principles of the various processes employed.</p>
+
+<p><b>217. Estimation of Sucrose in the Expressed Juice.</b>—In the
+first method the beets are reduced by any good shredding machine, to
+a fine pulp, which is placed in a press and the juice expressed. In
+this liquor, after clarification with lead subacetate, the sucrose is
+determined by the polariscope. The methods of measuring, clarifying and
+polarizing are the same as those described for saccharine juices in
+paragraphs <b><a href="#P_83">83-85</a></b>. The mean percentage of juice in the sugar beet
+is ninety-five. The corrected polariscopic reading obtained multiplied
+by 0.95 will give the percentage of sugar in the beet.</p>
+
+<p><i>Example.</i>—The solids in a sample of beet juice, as measured by a
+brix spindle, are 17.5 per cent. Double the normal weight of the juice
+is measured from a sucrose pipette, placed in a sugar flask, clarified,
+the volume completed to 100 cubic centimeters, the contents of the
+flask well shaken and filtered. The polariscopic reading obtained is
+29°.0. Then (29.0 ÷ 2) × 0.95 = 13.8 = percentage of sucrose in the beet.
+<span class="pagenum"><a id="Page_243"></a>[Pg 243]</span></p>
+
+<p><b>218. Instantaneous Diffusion.</b>—In the second process employed
+for determining the sugar content of beets, the principle involved
+depends on the use of a pulp so finely divided as to permit of
+the almost instant diffusion of the sugar present throughout the
+added liquid. This diffusion takes place even in the cold and the
+process thus presents a convenient and rapid method for the accurate
+determination of the percentage of sugar in beets. The pulping is
+accomplished by means of the machine described on <a href="#Page_10">page 10</a>,
+or the one shown in <a href="#FIG_67">Fig. 67</a>. The beet is pressed against the rapidly
+revolving rasp by means of the grooved movable block and the finely divided pulp
+is received in the box below. These machines afford a pulp which is
+impalpable and which readily permits an almost instantaneous diffusion
+of its sugar content.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_67" src="images/fig67.jpg" alt="" width="450" height="505" >
+    <p class="center">Fig 67. Apparatus for Pulping Beets.</p>
+</div>
+
+<p><b>219. Pellet’s Method of Cold Diffusion.</b>—The impalpable pulp
+having been obtained, by one of the processes described, the content of
+sugar therein is determined as follows:<a id="FNanchor_181" href="#Footnote_181" class="fnanchor">[181]</a></p>
+
+<p>A normal or double normal quantity of the pulp is quickly weighed, to
+<span class="pagenum"><a id="Page_244"></a>[Pg 244]</span>
+avoid evaporation, in a sugar dish with an appropriate lip, and washed
+into the flask, which should be graduated, as shown in <a href="#FIG_68">Fig. 68</a>,
+to allow for the volume of the fiber or marc of the beet. Since the beet
+pulp contains, on an average, four per cent of marc, the volume which
+is occupied thereby is assumed to be a little more than one cubic
+centimeter. Since it is advisable to have as large a volume of water
+as convenient, it is the practice of Pellet to wash the pulp into a
+flask graduated at 201.35 cubic centimeters. If a 200 cubic centimeter
+flask be used, the weight of the pulp should be 25.87 instead of
+26.048 grams. After the pulp is washed into the flask, about six cubic
+centimeters of lead subacetate of 30° baumé are added, together with a
+little ether, to remove the foam. The flask is now gently shaken and
+water added to the mark and the contents thoroughly shaken. If the pulp
+is practically perfect, the filtration and polarization may follow
+immediately. The filter into which the contents of the flask are poured
+should be large enough to hold the whole quantity. It is recommended
+to add a drop or two of strong acetic acid just before completing
+the volume of the liquid in the flask to the mark. The polarization
+should be made in a 400 millimeter tube, which will give directly the
+percentage of sugar present. It is not necessary to heat the solution
+in order to insure complete diffusion, but the temperature at which the
+operation is conducted should be the ordinary one of the laboratory.
+In case the pulp is not as fine as should be, the flask should be
+allowed to stand for half an hour after filling, before filtration.
+An insufficient amount of lead subacetate may permit some rotatory
+bodies other than sugar to pass into solution, and care should be
+taken to have always the proper quantity of clarifying material added.
+The presence of these rotating bodies, mostly of a pectic nature,
+may be shown by extracting the pulp first with cold water until all
+the sugar is removed, and afterwards with boiling water. The liquor
+obtained from the last precipitation will show a decided right-handed
+rotation, unless first treated with lead subacetate, in which case
+the polarization will be zero. A very extended experience with the
+instantaneous cold aqueous diffusion has shown that the results
+obtained thereby are quite as reliable as those given by hot alcoholic
+or aqueous digestion.</p>
+
+<p><span class="pagenum"><a id="Page_245"></a>[Pg 245]</span>
+<b>220. Flask for Cold Diffusion and Alcohol Digestion.</b>—For
+convenience in washing the pulp into the sugar flask, the latter is
+made with an enlarged mouth as shown in <a href="#FIG_68">Fig. 68</a>.
+The dish holding the weighed quantity of pulp is held with the lip in
+the mouth of the flask, and the pulp washed in by means of a jet of
+water furnished from a pressure bottle or washing flask. The flask
+shown is graduated for the normal weight of pulp, <i>viz.</i>, 26.048
+grams. The marking is on the constricted neck and extends from 100 to
+101.3 cubic centimeters. This permits of making the proper allowance
+for the volume occupied by the marc or fiber, but this is unnecessary
+for the usual character of control analyses. In the case of healthy,
+fresh beets, the volume occupied by the marc is nearly one and
+three-tenths cubic centimeters for the normal polariscopic weight of
+26.048 grams of pulp. For the laurent instrument this volume is nearly
+one cubic centimeter.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_68" src="images/fig68.jpg" alt="" width="500" height="451" >
+    <p class="center">Figure 68. Apparatus for Cold Diffusion.</p>
+</div>
+
+<p id="P_221"><b>221. Extraction with Alcohol.</b>—The third method of determining
+sugar in beets is by alcoholic extraction. The principle of the method
+is based on the fact that aqueous alcohol of not more than eighty per
+<span class="pagenum"><a id="Page_246"></a>[Pg 246]</span>
+cent strength will extract all the sugar from the pulp, but will not
+dissolve the pectic and other rotatory bodies, which, in solution,
+are capable of disturbing the rotatory power of the sugar present.
+It is also further to be observed that the rotatory power of pure
+sucrose, in an aqueous alcoholic solution, is not sensibly different
+from that which is observed in a purely aqueous liquid. The pulp,
+which is to be extracted, should be in as fine a state of subdivision
+as convenient, and the process may be carried on in any of the forms
+of extraction apparatus already described, or in the apparatus shown
+in <a href="#FIG_69">Fig. 69</a>. The extraction tube, of the ordinary
+forms of apparatus, however, is scarcely large enough to hold the
+required amount of pulp, and therefore special tubes and forms of
+apparatus have been devised for this method of procedure. In weighing
+the pulp for extraction, a quarter, half, or the exact amount required
+for the polariscope employed, should be used. If the tubes are of
+sufficient size the full weight may be taken, <i>viz.</i>, 26.048
+or 16.19 grams for the instruments in ordinary use. Since the pulp
+contains a large quantity of water, the extraction could be commenced
+with alcohol of standard strength, <i>viz.</i>, about ninety-five per
+cent. The volume of alcohol employed should be such as will secure a
+strength of from seventy to eighty per cent when mixed with the water
+contained in the pulp. The flask receiving the extract should be kept
+in continuous ebullition and the process may be regarded as complete
+in about one hour, when the pulp has been properly prepared. The
+method of extracting beet pulp with alcohol is due to Scheibler, and
+in its present form the process is conducted according to the methods
+described by Scheibler, Sickel, and Soxhlet.<a id="FNanchor_182" href="#Footnote_182" class="fnanchor">[182]</a></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_69" src="images/fig69.jpg" alt="" width="300" height="639" >
+    <p class="center">Fig. 69. Sickel-Soxhlet Extractor.</p>
+</div>
+
+<p>If the pulp be obtained by any other means than that of a fine rasp,
+the extraction of the sugar by the aqueous alcohol takes a long time,
+and even a second extraction may be necessary. It is convenient to use
+as a flask for holding the solvent, one already graduated at 100 or 110
+cubic centimeters. A flask especially constructed for this purpose, has
+a constricted neck on which the graduations are made, and a wide mouth
+serving to attach it to the extracting apparatus, as shown in <a href="#FIG_68">Fig. 68</a>.
+When the extract is obtained in this way, it is not necessary to
+transfer it to a new flask before preparing it for polarization. When
+<span class="pagenum"><a id="Page_247"></a>[Pg 247]</span>
+the extraction is complete, the source of heat is removed, and when all
+the alcohol is collected in the flask, the latter is removed from the
+extraction apparatus, cooled to room temperature, a sufficient quantity
+of lead subacetate added, the flask well shaken, the volume completed
+to the mark with water, again well shaken and the contents of the flask
+thrown upon the filter. It is important to avoid loss of alcohol during
+filtration. For this purpose it is best to have a folded filter and to
+cover the funnel immediately after pouring the contents of the flask
+upon the filter paper, with a second larger funnel. The stem of the
+<span class="pagenum"><a id="Page_248"></a>[Pg 248]</span>
+funnel carrying the filter paper, should dip well into the flask
+receiving the filtrate. As in other cases of filtering sugar juices for
+polarization, the first portions of the filtrate received should be
+rejected. The percentage of sugar is obtained in the filtrate in the
+usual way.</p>
+
+<p>Where a weight of pulp equal to the normal factor of the polariscope
+employed is used, and the extract collected in a 100 cubic centimeter
+flask, the percentage of sugar is directly obtained by making the
+reading in a 200 millimeter tube. With other weights of pulp, or other
+sizes of flask, the length of the observation tube may be changed or
+the reading obtained corrected by multiplication or division by an
+appropriate factor. A battery of sickel-soxhlet extractors is shown in
+<a href="#FIG_69">Fig. 69</a>.<a id="FNanchor_183" href="#Footnote_183" class="fnanchor">[183]</a></p>
+
+<div class="figleft smcap">
+    <img id="FIG_70" src="images/fig70.jpg" alt="" width="100" height="433" >
+    <p class="center">Fig. 70.</p>
+</div>
+
+<p><b>222. Scheibler’s Extraction Tube.</b>—In order to secure a speedy
+extraction of large quantities of pulp, Scheibler recommends the use of
+the extraction tube shown in <a href="#FIG_70">Fig. 70</a>.<a id="FNanchor_184" href="#Footnote_184" class="fnanchor">[184]</a>
+The apparatus is composed of three concentric glass cylinders. The
+outer and middle cylinders are sealed together at the top, and the
+inner one is movable and carries a perforated diaphragm below, for
+filtering purposes. Near the top it is provided with small circular
+openings, whereby the alcoholic vapors may gain access to the condenser
+(not shown). The middle cylinder is provided with two series of
+apertures, through the higher of which the vapor of alcohol passes to
+the condenser, while the alcohol which has passed through the pulp and
+collected between the inner and middle cylinders, flows back through
+the lower into the flask (not shown) containing the boiling alcohol.</p>
+
+<p>The middle cylinder is provided with a curved bottom to prevent the
+filtering end of the inner tube from resting too tightly against it.</p>
+
+<p>The tube containing the pulp is thus protected from the direct heat
+of the alcoholic vapors during the progress of extraction by a thin
+cushion of liquid alcohol.</p>
+
+<p><b>223. Alcoholic Digestion.</b>—The fourth method of determining
+sugar in beet pulp, is by means of digestion with hot alcohol. The
+<span class="pagenum"><a id="Page_249"></a>[Pg 249]</span>
+principle of this method is precisely the same as that which is
+involved in aqueous diffusion in the cold. The diffusion, however,
+in the case of the alcohol, is not instantaneous, but is secured by
+maintaining the mixture of the pulp and alcohol for some time at or
+near the boiling point. The methods of preparing the pulp, weighing
+it and introducing it into the digestion flask are precisely those
+used for aqueous digestion, but in the present case a somewhat coarser
+pulp may be employed. The method is commonly known as the rapp-degener
+process.<a id="FNanchor_185" href="#Footnote_185" class="fnanchor">[185]</a></p>
+
+<p>Any convenient method of heating the alcohol may be used. In this
+laboratory the flasks are held on a false bottom in a bath composed of
+two parts of glycerol and one of water. One side of the bath holder
+is made of glass, as shown in <a href="#FIG_71">Fig. 71</a>, in order
+to keep the flasks in view. In order to avoid the loss of alcohol,
+the digestion flask should be provided with a reflux condenser, or be
+attached to an ordinary condenser, which will reduce the vapors of
+alcohol again to a liquid. Unless the weather be very warm, the reflux
+condenser may consist of a glass tube of rather wide bore and at least
+one meter in length, as shown in <a href="#FIG_71">Fig. 71</a>. A
+slight loss of alcohol during the digestion is of little consequence. A
+convenient method of procedure is the following.</p>
+
+<p>Double the quantity of the beet pulp required for the ventzke
+polariscope, <i>viz.</i>, 52.096 grams, weighed in a lipped metal
+dish, is washed, by means of alcohol, into a flask marked at 202.6
+cubic centimeters, and the flask filled two-thirds with ninety-five
+per cent alcohol and well shaken. Afterwards, a proper quantity of
+lead subacetate is added, and then sufficient alcohol to complete the
+volume to the mark. The flask is then attached to the condenser, placed
+in a water-glycerol bath and heated to a temperature of 75° for about
+forty-five minutes. At the end of this time, the flask is removed
+from the bath and condenser, cooled quickly with water, alcohol added
+to the mark and well shaken. The filtration should be accomplished
+with precautions, to avoid the loss of alcohol mentioned in paragraph
+<b><a href="#P_221">221</a></b>. The filtrate is examined in the polariscope in a 200
+millimeter tube, and the reading obtained gives directly the percentage
+of sugar in the sample examined. Half the quantity of pulp mentioned,
+in a 101.3 cubic centimeter flask, may also be used. A convenient form
+<span class="pagenum"><a id="Page_250"></a>[Pg 250]</span>
+of arranging a battery of flasks is shown in the accompanying figure.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_71" src="images/fig71.jpg" alt="" width="400" height="482" >
+    <p class="center spb1">Fig. 71. Battery for Alcoholic Digestion.</p>
+</div>
+
+<p><b>224. Determination of Sugar in Mother Beets.</b>—In selecting
+mother beets for seed production, it is necessary to secure only those
+of a high sugar content. This is accomplished by boring a hole about
+two and a half centimeters in diameter obliquely through the beet by
+means of the apparatus shown in <a href="#FIG_72">Fig. 72</a>.</p>
+
+<p>The beet is not injured for seed production by this process, and the
+pulp obtained is used for the determination of sugar. The juice is
+expressed by means of the small hand press shown in <a href="#FIG_73">Fig. 73</a>.
+Since only a small quantity of juice is obtained, it is advisable to prepare
+it for polarization in a sugar flask marked at fifty cubic centimeters.
+The density of the juice, by reason of its small volume, is easiest
+<span class="pagenum"><a id="Page_251"></a>[Pg 251]</span>
+obtained by the hydrostatic balance, as described in paragraph
+<b><a href="#P_53">53</a></b>. In lieu of this, the juice may be quickly weighed in a
+counterbalanced dish on a balance giving results accurate to within
+one milligram. The rest of the analytical process is similar to that
+already described.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_72" src="images/fig72.jpg" alt="" width="600" height="336" >
+    <p class="center spb1">Fig. 72. Rasp for Sampling Mother Beets.</p>
+    <img id="FIG_73" src="images/fig73.jpg" alt="" width="600" height="371" >
+    <p class="center spb1">Fig. 73. Hand Press for Beet Analysis.</p>
+    <img id="FIG_74" src="images/fig74.jpg" alt="" width="600" height="217" >
+    <p class="center spb1">Fig. 74.</p>
+</div>
+
+<p><b>225. Aqueous Diffusion.</b>—The process of instantaneous aqueous
+diffusion may also be applied to the examination of mother beets. For
+<span class="pagenum"><a id="Page_252"></a>[Pg 252]</span>
+this purpose the beets are perforated by a rasp, devised by Keil, shown
+lying on the floor in <a href="#FIG_72">Fig. 72</a>, the characteristics of which
+are shown in <a href="#FIG_74">Fig. 74</a>. The conical end of the rasp is roughened
+in such a way as to reduce the beet to an impalpable pulp. This end is fastened by
+a bayonet fastening to the cylindrical carrier or arm in such a way
+that, by means of a groove in the conical end of the rasp, the pulp is
+introduced into the cylinder. The cylinder is provided with a small
+piston by means of which the pulp can be withdrawn when the cylindrical
+portion of the rasp is detached from the driving machinery. It is
+important that the rasp be driven at a high rate of speed, <i>viz.</i>,
+from 1500 to 2000 revolutions a minute. The sample of pulp at this rate
+of revolution is taken almost instantly, and with skilled manipulators
+the whole operation of taking a sample, removing the rasp by means of
+its bayonet fastenings, withdrawing the sample of pulp and replacing
+the rasp ready for another operation does not consume more than from
+ten to twenty seconds. From three to four samples may thus be taken in
+a minute. The samples of pulp as taken are dropped into numbered dishes
+corresponding to the numbers on the beets. One-quarter of the normal
+weight for the polariscope is used for the analysis. The pulp is placed
+in a fifty cubic centimeter flask, water and lead subacetate added, the
+flask well shaken, filled to the mark with water, again well shaken,
+the contents thrown on the filter, and the filtrate polarized in a 400
+millimeter tube, giving the direct percentage of sugar. For practical
+purposes the percentage of marc in the beet may be neglected. If the
+polarization take place in a 200 millimeter tube the number obtained
+should be multiplied by two for the content of sugar.</p>
+
+<p>In numbering sugar beets which are to be analyzed for seed production,
+it is found that a small perforated tin tag bearing a number may be
+safely affixed to the beet by means of a tack. It is not safe to use
+paper tags as they may become illegible by becoming wet before the
+<span class="pagenum"><a id="Page_253"></a>[Pg 253]</span>
+sorting of the beets is completed. Where from 1000 to 2000 beets
+are to be examined in a day, the number of the beets and the dishes
+corresponding thereto must be carefully controlled to avoid confusion
+and mistakes.</p>
+
+<p><b>226. Determination of Sugars without Weighing.</b>—An ingenious
+device for the rapid analysis of mother beets is based upon the use of
+a machine which cuts from the beet a core of given dimensions and this
+core is subsequently reduced to a pulp which is treated with cold water
+and polarized in the manner described above. The cutting knives of the
+sampler can be adjusted to take a core of any desired size. Since the
+beets used for analysis have essentially the same specific gravity, the
+cores thus taken weigh sensibly the same and the whole core is used
+for the analysis, thus doing away with the necessity of weighing. The
+core obtained is reduced to a pulp in a small machine so adjusted as
+to permit the whole of the pulp, when prepared, to be washed directly
+into the sugar flask. By the use of this machine a very large number of
+analyses can be made in a single day, and this is highly important in
+the selection of mother beets, for often 50,000 or 100,000 analyses are
+to be made in a short time.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_75A" src="images/fig75.jpg" alt="" width="600" height="213" >
+    <p class="center spb1">Fig. 75. Tube for Continuous Observation.</p>
+</div>
+
+<p><b>227. Continuous Diffusion Tube.</b>—To avoid the delay occasioned
+by filling and emptying observation tubes in polariscopic work, where
+large numbers of analyses of canes and beets are to be made, Pellet
+has devised a continuous diffusion tube, by means of which a solution,
+which has just been observed, is rapidly and completely displaced by a
+fresh solution. This tube, improved by Spencer, is shown in <a href="#FIG_75A">Fig. 75</a>.
+The fresh solution is poured in at the funnel, displacing completely the
+<span class="pagenum"><a id="Page_254"></a>[Pg 254]</span>
+old solution which flows out through the tube at the other end. The
+observer watches the field vision and is able to tell when the old
+solution is completely displaced by the clearing of the field, at
+which time the reading of the new solution can be quickly made. When
+solutions are all ready for examination an expert observer can easily
+read, by the aid of this device, from four to five of them in a minute.</p>
+
+<p><b>228. Analysis of Sirups and Massecuites.</b>—The general principles
+which control the analysis of sirups and massecuites are the same
+whether these products be derived from canes or beets. In the case
+of the products of canes, the sirups or massecuites contain chiefly
+sucrose, invert sugar, and other copper reducing bodies, inorganic
+matters and water. In the case of products derived from sugar beets
+the contents are chiefly sucrose, inorganic matters, a trace of invert
+sugar, raffinose and water. The principles of the determination of
+these various constituents have already been described.</p>
+
+<p><b>229. Specific Gravity.</b>—The specific gravity of sirups and
+molasses can be determined by the spindle in the usual way, but in
+the case of molasses which is quite dense, the spindle method is not
+reliable. It is better, therefore, both in molasses and massecuites,
+to determine the density by dilution. For this purpose, as described
+by Spencer, a definite weight of material, from 200 to 250 grams, is
+dissolved in water and the volume of the solution completed to half a
+liter. A portion of the solution is then placed in a cylinder and the
+quantity of total solids contained therein determined in the usual way
+by a brix or specific gravity hydrometer. In case 250 grams of the
+material be used the calculation of the brix degree for the original
+material is conducted according to the following formula:</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>x</i> =&nbsp;</td>
+      <td class="tdc bb">G × <i>B</i> × <i>V</i></td>
+   </tr><tr>
+      <td class="tdc"><i>W</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p>In the above formula <i>x</i> is the required brix degree, <i>V</i>
+the volume of the solution, <i>B</i> the observed brix degree of the
+solution, and G the corresponding specific gravity obtained from the
+table on <a href="#Page_73">page 73</a>. When only small quantities of the material are at
+hand the hydrostatic balance (<b><a href="#P_53">53</a></b>) should be employed. For this
+<span class="pagenum"><a id="Page_255"></a>[Pg 255]</span>
+purpose twenty-five grams of the material are dissolved in water and
+the volume of the solution made up to 100 cubic centimeters. The sinker
+of the hydrostatic balance is placed in the solution and equilibrium
+secured by placing the weights upon the arm of the balance in the usual
+manner. Since the arm of the balance is graduated to give, by direct
+reading, the specific gravity, the density can be obtained at once.</p>
+
+<div class="blockquot">
+<p><i>Example.</i>—Let the position of the weights or riders upon the
+balance arm be as follows:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">(1) at point of suspension of the bob &nbsp;</td>
+      <td class="tdr">= 1.000</td>
+   </tr><tr>
+      <td class="tdl">(3) at mark 7 on beam</td>
+      <td class="tdr">= 0.07&#8199;</td>
+   </tr><tr>
+      <td class="tdl">(4) at mark 9 on beam</td>
+      <td class="tdr">= 0.009</td>
+   </tr><tr>
+      <td class="tdl_ws2">Specific gravity</td>
+      <td class="tdr">= 1.079</td>
+   </tr>
+ </tbody>
+</table>
+</div>
+
+<p>The nearest brix degree corresponding to this specific gravity
+(<b><a href="#P_58">58</a></b>) is 19. The total weight of the solution is equal to 100 ×
+1.079, <i>viz.</i>, 107.9 grams. Since the solution contains nineteen
+per cent of solid matter as determined by the hydrostatic balance, the
+total weight of solid matter therein is 107.9 × 19 ÷ 100 = 20.5 grams.
+The total per cent. of solid matter in the original sample is therefore
+20.5 ÷ 25 × 100 = 82 and the specific gravity corresponding thereto
+(<a href="#Page_74">page 74</a>) is 1.42934.</p>
+
+<p>The specific gravity of a massecuite may also be determined in
+pyknometers especially constructed for this
+purpose.<a id="FNanchor_186" href="#Footnote_186" class="fnanchor">[186]</a></p>
+
+<p id="P_23"><b>230. Determination Of Water.</b>—The accurate determination of
+water in sirups and massecuites is a matter of considerable difficulty.
+The principles of conducting the process (<b><a href="#P_26">26</a></b>), applicable also
+to the determination of water in honeys and other viscous liquids,
+are as follows: In all cases where invert sugar is present the drying
+should be conducted at a temperature not exceeding 75° or 80°. In
+dense molasses and massecuites a weighed quantity should be dissolved
+and made up to a definite volume and an aliquot portion taken for
+the determination. In order to secure complete desiccation at a low
+temperature, the drying should be accomplished in partial vacuum
+(pages <a href="#Page_22">22</a>, <a href="#Page_23">23</a>).
+The process of desiccation should be conducted in shallow,
+flat-bottom dishes which may be conveniently and cheaply made of
+aluminum and the process is hastened by filling the dish previously
+<span class="pagenum"><a id="Page_256"></a>[Pg 256]</span>
+with thoroughly dried fragments of pumice stone. When the sample does
+not contain any invert sugar the desiccation can be safely accomplished
+at the temperature of boiling water. Drying should be continued in all
+cases until practically constant weight is obtained.</p>
+
+<p><b>231. Determination Of Ash.</b>—Ash is an important constituent of
+the sirups, molasses, and massecuites from canes and exists in very
+much larger quantities in the same products from beets. The ash may be
+determined directly by careful incineration, but it is customary to add
+a few drops of sulfuric acid, sufficient to combine with all the bases
+present and be in slight excess. The presence of sulfuric acid is of
+some advantage in the beginning of the carbonization and renders the
+process somewhat easier of accomplishment. When sulfuric acid is used,
+the weight of ash obtained must be diminished by one-tenth to allow for
+the increased weight obtained by the conversion of the carbonates into
+sulfates. In general, the principles and methods described on
+<a href="#Page_36">pages 36-40</a> are to be employed.</p>
+
+<p><b>232. Determination of Reducing Sugars in Sirups, Molasses, and
+Massecuites.</b>—The quantity of reducing sugars in the products
+derived from the sugar beet, as a rule, is insignificant. In the
+products from sugar cane there are large quantities of reducing matters
+which, in general, are determined by any of the standard methods
+already given. It has been shown by the author<a id="FNanchor_187" href="#Footnote_187" class="fnanchor">[187]</a>
+that the juices of healthy sugar canes contain a small quantity of
+invert sugar, but this statement has been contradicted by Bloufret.<a id="FNanchor_188" href="#Footnote_188" class="fnanchor">[188]</a>
+It is certain, however, that the reducing bodies derived from the
+products of manufacture of sugar cane and sorghum deport themselves in
+a manner somewhat different from pure invert sugar. In the absence of
+definite information in respect of the constitution of these bodies,
+the methods applicable to dextrose and invert sugar may be applied.</p>
+
+<p>Since the paragraphs relating to these processes were printed some
+important improvements in the preparation of the alkaline copper
+solutions have been made. The copper carbonate solution, as has already
+been said, is peculiarly suited to the determination of reducing sugars
+in the presence of sucrose and the modified forms of this solution, and
+<span class="pagenum"><a id="Page_257"></a>[Pg 257]</span>
+the methods of employing them with invert sugar, dextrose, levulose,
+and maltose, are described below.</p>
+
+<p><b>233. Estimation of Minute Quantities of Invert Sugar in
+Mixtures.</b>—The method of Hiller and Meissl, paragraph <b><a href="#P_142">142</a></b>,
+may be used for the estimation of small quantities of invert sugar
+in mixtures. A modified form of Soldaini’s reagent is, however, to
+be preferred for this purpose. Ost has proposed and tested a copper
+carbonate solution for the purpose mentioned which gives reliable
+results.<a id="FNanchor_189" href="#Footnote_189" class="fnanchor">[189]</a>
+The solution has the following composition:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl_top" rowspan="3">One liter contains</td>
+      <td class="tdr_wsp">3.6</td>
+      <td class="tdc">grams</td>
+      <td class="tdl_wsp">crystallized copper sulfate.</td>
+   </tr><tr>
+      <td class="tdr_wsp">250.0</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">potassium carbonate.</td>
+   </tr><tr>
+      <td class="tdr_wsp">100.0</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">hydrogen potassium sulfate.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>This reagent undergoes no change when kept for a long while, especially
+in large vessels. Even in smaller vessels it can be kept for a year or
+more without undergoing any change.</p>
+
+<p>The method of analysis is the same as that described in paragraph
+<b><a href="#P_128">128</a></b>, with the exception that the boiling is continued for only
+five minutes instead of ten, and the quantities of the copper and sugar
+solutions used are doubled, being 100 and fifty cubic centimeters
+respectively. In no case must the solution used contain more than
+thirty-eight milligrams of invert sugar. The quantity of sucrose in
+the mixture is obtained by polarization (<b><a href="#P_94">94</a></b>). Ost has also
+recalculated the reduction values of the common sugars for the strong
+copper carbonate solution, and the numbers obtained are slightly
+different from those given on <a href="#Page_142">page 142</a>.<a id="FNanchor_190" href="#Footnote_190" class="fnanchor">[190]</a></p>
+
+<p>For different percentages of invert sugar in mixtures of sucrose, the
+quantities of invert sugar are calculated from the number of milligrams
+of copper obtained by the following table:
+<span class="pagenum"><a id="Page_258"></a>[Pg 258]</span></p>
+
+<ul class="index fs_110">
+<li class="isub4"><b>(A)</b> = Milligrams of copper obtained.</li>
+<li class="isub4"><b>(B)</b> = Pure invert sugar.</li>
+<li class="isub4"><b>(C)</b> = Invert sugar.</li>
+<li class="isub4"><b>(D)</b> = Sucrose.</li>
+</ul>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc" colspan="2">&nbsp;</th>
+      <th class="tdc bb fs_105" colspan="7"><span class="smcap">Milligrams of Invert Sugar in Mixtures of</span></th>
+   </tr><tr>
+      <th class="tdc" colspan="2">&nbsp;</th>
+      <th class="tdc bl">5(C)</th>
+      <th class="tdc bl">2(C)</th>
+      <th class="tdc bl">1.5(C)</th>
+      <th class="tdc bl">1.0(C)</th>
+      <th class="tdc bl">0.8(C)</th>
+      <th class="tdc bl">0.6(C)</th>
+      <th class="tdc bl">0.5(C)</th>
+   </tr><tr>
+      <th class="tdc bb">&nbsp; (A) &nbsp;</th>
+      <th class="tdc bb">&nbsp; &nbsp;(B) &nbsp;</th>
+      <th class="tdc bl bb">&nbsp;95(D)&nbsp;</th>
+      <th class="tdc bl bb">&nbsp;98(D)&nbsp;</th>
+      <th class="tdc bl bb">&nbsp;98.5(D)&nbsp;</th>
+      <th class="tdc bl bb">&nbsp;99.0(D)&nbsp;</th>
+      <th class="tdc bl bb">&nbsp;99.2(D)&nbsp;</th>
+      <th class="tdc bl bb">&nbsp;99.4(D)&nbsp;</th>
+      <th class="tdc bl bb">&nbsp;99.5(D)&nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">88</td>
+      <td class="tdr_wsp bl">37.9</td>
+      <td class="tdr_wsp bl">37.1</td>
+      <td class="tdr_wsp bl">36.0</td>
+      <td class="tdl_ws1 bl">35.4</td>
+      <td class="tdl_ws1 bl">34.7</td>
+      <td class="tdl_ws1 bl">34.2</td>
+      <td class="tdl_ws1 bl">33.9</td>
+      <td class="tdl_ws1 bl">33.6</td>
+   </tr><tr>
+      <td class="tdc">85</td>
+      <td class="tdr_wsp bl">36.3</td>
+      <td class="tdr_wsp bl">35.5</td>
+      <td class="tdr_wsp bl">34.5</td>
+      <td class="tdl_ws1 bl">34.0</td>
+      <td class="tdl_ws1 bl">33.4</td>
+      <td class="tdl_ws1 bl">32.9</td>
+      <td class="tdl_ws1 bl">32.5</td>
+      <td class="tdl_ws1 bl">32.2</td>
+   </tr><tr>
+      <td class="tdc">80</td>
+      <td class="tdr_wsp bl">33.9</td>
+      <td class="tdr_wsp bl">33.0</td>
+      <td class="tdr_wsp bl">33.2</td>
+      <td class="tdl_ws1 bl">31.7</td>
+      <td class="tdl_ws1 bl">31.2</td>
+      <td class="tdl_ws1 bl">30.7</td>
+      <td class="tdl_ws1 bl">30.2</td>
+      <td class="tdl_ws1 bl">29.9</td>
+   </tr><tr>
+      <td class="tdc">75</td>
+      <td class="tdr_wsp bl">31.6</td>
+      <td class="tdr_wsp bl">30.7</td>
+      <td class="tdr_wsp bl">30.0</td>
+      <td class="tdl_ws1 bl">29.5</td>
+      <td class="tdl_ws1 bl">29.0</td>
+      <td class="tdl_ws1 bl">28.5</td>
+      <td class="tdl_ws1 bl">28.1</td>
+      <td class="tdl_ws1 bl">27.7</td>
+   </tr><tr>
+      <td class="tdc">70</td>
+      <td class="tdr_wsp bl">29.4</td>
+      <td class="tdr_wsp bl">28.5</td>
+      <td class="tdr_wsp bl">27.8</td>
+      <td class="tdl_ws1 bl">27.4</td>
+      <td class="tdl_ws1 bl">26.8</td>
+      <td class="tdl_ws1 bl">26.4</td>
+      <td class="tdl_ws1 bl">25.9</td>
+      <td class="tdl_ws1 bl">25.6</td>
+   </tr><tr>
+      <td class="tdc">65</td>
+      <td class="tdr_wsp bl">27.3</td>
+      <td class="tdr_wsp bl">26.3</td>
+      <td class="tdr_wsp bl">25.7</td>
+      <td class="tdl_ws1 bl">25.3</td>
+      <td class="tdl_ws1 bl">24.7</td>
+      <td class="tdl_ws1 bl">24.3</td>
+      <td class="tdl_ws1 bl">23.8</td>
+      <td class="tdl_ws1 bl">23.5</td>
+   </tr><tr>
+      <td class="tdc">60</td>
+      <td class="tdr_wsp bl">25.2</td>
+      <td class="tdr_wsp bl">24.2</td>
+      <td class="tdr_wsp bl">23.6</td>
+      <td class="tdl_ws1 bl">23.2</td>
+      <td class="tdl_ws1 bl">22.6</td>
+      <td class="tdl_ws1 bl">22.2</td>
+      <td class="tdl_ws1 bl">21.8</td>
+      <td class="tdl_ws1 bl">21.5</td>
+   </tr><tr>
+      <td class="tdc">55</td>
+      <td class="tdr_wsp bl">23.1</td>
+      <td class="tdr_wsp bl">22.1</td>
+      <td class="tdr_wsp bl">21.6</td>
+      <td class="tdl_ws1 bl">21.2</td>
+      <td class="tdl_ws1 bl">20.6</td>
+      <td class="tdl_ws1 bl">20.2</td>
+      <td class="tdl_ws1 bl">19.8</td>
+      <td class="tdl_ws1 bl">19.6</td>
+   </tr><tr>
+      <td class="tdc">50</td>
+      <td class="tdr_wsp bl">21.2</td>
+      <td class="tdr_wsp bl">20.1</td>
+      <td class="tdr_wsp bl">19.6</td>
+      <td class="tdl_ws1 bl">19.2</td>
+      <td class="tdl_ws1 bl">18.6</td>
+      <td class="tdl_ws1 bl">18.3</td>
+      <td class="tdl_ws1 bl">17.9</td>
+      <td class="tdl_ws1 bl">17.7</td>
+   </tr><tr>
+      <td class="tdc">45</td>
+      <td class="tdr_wsp bl">19.3</td>
+      <td class="tdr_wsp bl">18.2</td>
+      <td class="tdr_wsp bl">17.6</td>
+      <td class="tdl_ws1 bl">17.2</td>
+      <td class="tdl_ws1 bl">16.7</td>
+      <td class="tdl_ws1 bl">16.3</td>
+      <td class="tdl_ws1 bl">16.0</td>
+      <td class="tdl_ws1 bl">15.8 </td>
+   </tr><tr>
+      <td class="tdc">40</td>
+      <td class="tdr_wsp bl">17.3</td>
+      <td class="tdr_wsp bl">16.3</td>
+      <td class="tdr_wsp bl">15.7</td>
+      <td class="tdl_ws1 bl">15.3</td>
+      <td class="tdl_ws1 bl">14.8</td>
+      <td class="tdl_ws1 bl">14.5</td>
+      <td class="tdl_ws1 bl">14.2</td>
+      <td class="tdl_ws1 bl">14.0</td>
+   </tr><tr>
+      <td class="tdc">35</td>
+      <td class="tdr_wsp bl">15.4</td>
+      <td class="tdr_wsp bl">14.5</td>
+      <td class="tdr_wsp bl">13.8</td>
+      <td class="tdl_ws1 bl">13.4</td>
+      <td class="tdl_ws1 bl">13.0</td>
+      <td class="tdl_ws1 bl">12.7</td>
+      <td class="tdl_ws1 bl">12.5</td>
+      <td class="tdl_ws1 bl">12.3</td>
+   </tr><tr>
+      <td class="tdc">30</td>
+      <td class="tdr_wsp bl">13.5</td>
+      <td class="tdr_wsp bl">12.6</td>
+      <td class="tdr_wsp bl">12.0</td>
+      <td class="tdl_ws1 bl">11.6</td>
+      <td class="tdl_ws1 bl">11.2</td>
+      <td class="tdl_ws1 bl">11.0</td>
+      <td class="tdl_ws1 bl">10.8</td>
+      <td class="tdl_ws1 bl">10.6</td>
+   </tr><tr>
+      <td class="tdc">25</td>
+      <td class="tdr_wsp bl">11.5</td>
+      <td class="tdr_wsp bl">10.8</td>
+      <td class="tdr_wsp bl">10.3</td>
+      <td class="tdl_ws1 bl">10.0</td>
+      <td class="tdl_ws1 bl">&#8199;9.5</td>
+      <td class="tdl_ws1 bl">&#8199;9.3</td>
+      <td class="tdl_ws1 bl">&#8199;9.1</td>
+      <td class="tdl_ws1 bl">&#8199;9.0</td>
+   </tr><tr>
+      <td class="tdc">20</td>
+      <td class="tdr_wsp bl">&#8199;9.6</td>
+      <td class="tdr_wsp bl">&#8199;9.1</td>
+      <td class="tdr_wsp bl">&#8199;8.6</td>
+      <td class="tdl_ws1 bl">&#8199;8.3</td>
+      <td class="tdl_ws1 bl">&#8199;7.9</td>
+      <td class="tdl_ws1 bl">&#8199;7.7</td>
+      <td class="tdl_ws1 bl">&#8199;7.5</td>
+      <td class="tdl_ws1 bl">&#8199;7.3</td>
+   </tr><tr>
+      <td class="tdc">15</td>
+      <td class="tdr_wsp bl">&#8199;7.7</td>
+      <td class="tdr_wsp bl">&#8199;7.3</td>
+      <td class="tdr_wsp bl">&#8199;6.9</td>
+      <td class="tdl_ws1 bl">&#8199;6.7</td>
+      <td class="tdl_ws1 bl">&#8199;6.3</td>
+      <td class="tdl_ws1 bl">&#8199;6.1</td>
+      <td class="tdl_ws1 bl">&#8199;5.8</td>
+      <td class="tdl_ws1 bl">&#8199;5.6</td>
+   </tr><tr class="bb">
+      <td class="tdc">10</td>
+      <td class="tdr_wsp bl">&#8199;5.8</td>
+      <td class="tdr_wsp bl">&#8199;5.4</td>
+      <td class="tdr_wsp bl">&#8199;5.1</td>
+      <td class="tdl_ws1 bl">&#8199;5.0</td>
+      <td class="tdl_ws1 bl">&#8199;4.7</td>
+      <td class="tdl_ws1 bl">&#8199;4.5</td>
+      <td class="tdl_ws1 bl">&#8199;4.2</td>
+      <td class="tdl_ws1 bl">&#8199;3.9</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc">&nbsp;</th>
+      <th class="tdc bb fs_105" colspan="6"><span class="smcap">Milligrams of Invert Sugar in Mixtures of</span></th>
+   </tr><tr>
+      <th class="tdc">&nbsp;</th>
+      <th class="tdc bl">0.4(C)</th>
+      <th class="tdc bl">0.3(C)</th>
+      <th class="tdc bl">0.2(C)</th>
+      <th class="tdc bl">0.1(C)</th>
+      <th class="tdc bl">0.05(C)</th>
+      <th class="tdc bl">0.02(C)</th>
+   </tr><tr>
+      <th class="tdc bb">&nbsp; (A) &nbsp;</th>
+      <th class="tdc bl bb">&nbsp;99.6(D)&nbsp;</th>
+      <th class="tdc bl bb">&nbsp;99.7(D)&nbsp;</th>
+      <th class="tdc bl bb">&nbsp;99.8(D)&nbsp;</th>
+      <th class="tdc bl bb">&nbsp;99.9(D)&nbsp;</th>
+      <th class="tdc bl bb">&nbsp;99.95(D)&nbsp;</th>
+      <th class="tdc bl bb">&nbsp;99.98(D)&nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">88</td>
+      <td class="tdr_wsp bl">33.3</td>
+      <td class="tdr_wsp bl">&nbsp;</td>
+      <td class="tdr_wsp bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">85</td>
+      <td class="tdr_wsp bl">32.0</td>
+      <td class="tdr_wsp bl">31.8</td>
+      <td class="tdr_wsp bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">80</td>
+      <td class="tdr_wsp bl">29.7</td>
+      <td class="tdr_wsp bl">29.5</td>
+      <td class="tdr_wsp bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">75</td>
+      <td class="tdr_wsp bl">27.4</td>
+      <td class="tdr_wsp bl">27.2</td>
+      <td class="tdr_wsp bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">70</td>
+      <td class="tdr_wsp bl">25.3</td>
+      <td class="tdr_wsp bl">25.0</td>
+      <td class="tdr_wsp bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">65</td>
+      <td class="tdr_wsp bl">23.2</td>
+      <td class="tdr_wsp bl">22.8</td>
+      <td class="tdr_wsp bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">60</td>
+      <td class="tdr_wsp bl">21.2</td>
+      <td class="tdr_wsp bl">20.8</td>
+      <td class="tdr_wsp bl">20.4</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">55</td>
+      <td class="tdr_wsp bl">19.3</td>
+      <td class="tdr_wsp bl">18.9</td>
+      <td class="tdr_wsp bl">18.5</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">50</td>
+      <td class="tdr_wsp bl">17.4</td>
+      <td class="tdr_wsp bl">17.0</td>
+      <td class="tdr_wsp bl">16.7</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">45</td>
+      <td class="tdr_wsp bl">15.6</td>
+      <td class="tdr_wsp bl">15.3</td>
+      <td class="tdr_wsp bl">14.9</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">40</td>
+      <td class="tdr_wsp bl">13.8</td>
+      <td class="tdr_wsp bl">13.5</td>
+      <td class="tdr_wsp bl">13.2</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">35</td>
+      <td class="tdr_wsp bl">12.1</td>
+      <td class="tdr_wsp bl">11.9</td>
+      <td class="tdr_wsp bl">11.5</td>
+      <td class="tdl_ws1 bl">10.3</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">30</td>
+      <td class="tdr_wsp bl">10.4</td>
+      <td class="tdr_wsp bl">10.2</td>
+      <td class="tdr_wsp bl">&#8199;9.9</td>
+      <td class="tdl_ws1 bl">&#8199;8.8</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">25</td>
+      <td class="tdr_wsp bl">&#8199;8.8</td>
+      <td class="tdr_wsp bl">&#8199;8.6</td>
+      <td class="tdr_wsp bl">&#8199;8.2</td>
+      <td class="tdl_ws1 bl">&#8199;7.3</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">20</td>
+      <td class="tdr_wsp bl">&#8199;7.1</td>
+      <td class="tdr_wsp bl">&#8199;6.9</td>
+      <td class="tdr_wsp bl">&#8199;6.6</td>
+      <td class="tdl_ws1 bl">&#8199;5.8</td>
+      <td class="tdl_ws1 bl">&#8199;4.9</td>
+      <td class="tdl_ws1 bl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">15</td>
+      <td class="tdr_wsp bl">&#8199;5.4</td>
+      <td class="tdr_wsp bl">&#8199;5.2</td>
+      <td class="tdr_wsp bl">&#8199;5.0</td>
+      <td class="tdl_ws1 bl">&#8199;4.4</td>
+      <td class="tdl_ws1 bl">&#8199;3.7</td>
+      <td class="tdl_ws1 bl">&#8199;2.0</td>
+   </tr><tr class="bb">
+      <td class="tdc">10</td>
+      <td class="tdr_wsp bl">&#8199;3.8</td>
+      <td class="tdr_wsp bl">&#8199;3.5</td>
+      <td class="tdr_wsp bl">&#8199;3.4</td>
+      <td class="tdl_ws1 bl">&#8199;3.0</td>
+      <td class="tdl_ws1 bl">&#8199;2.5</td>
+      <td class="tdl_ws1 bl">&#8199;1.7</td>
+   </tr>
+ </tbody>
+</table>
+
+<p id="P_234"><b>234. Soldaini’s Method Adapted to Gravimetric Work.</b>—By reason
+of their better keeping qualities and because of their less energetic
+action on non-reducing sugars, copper carbonate solutions are to be
+preferred to the alkaline copper tartrate solutions for gravimetric
+determinations of reducing sugars in cane juices and sugar house
+products, provided the difficulties which attend the manipulation
+can be removed. Ost has succeeded in securing perfectly satisfactory
+results with copper carbonate solution by slightly varying the
+composition thereof and continuing the boiling, for the reduction of
+the copper, ten minutes.<a id="FNanchor_191" href="#Footnote_191" class="fnanchor">[191]</a>
+The copper solution is made as follows:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdr_wsp">17.5</td>
+      <td class="tdc">grams</td>
+      <td class="tdl_wsp">crystallized copper sulfate.</td>
+   </tr><tr>
+      <td class="tdr_wsp">250.0</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">potassium carbonate.</td>
+   </tr><tr>
+      <td class="tdr_wsp">100.0</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp"><span class="ws2">”</span><span class="ws2">bicarbonate.</span></td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The above ingredients are dissolved in water and the volume of the
+solution completed to one liter. The object of the potassium bicarbonate
+<span class="pagenum"><a id="Page_259"></a>[Pg 259]</span>
+is to secure in the solution an excess of carbon dioxid and thus
+prevent the deposition of basic copper carbonate on keeping. The
+manipulation is conducted as follows:</p>
+
+<p>One hundred cubic centimeters of the copper solution are mixed with
+half that quantity of the sugar solution in a large erlenmeyer, which
+is placed upon a wire gauze, heated quickly to boiling and kept in
+ebullition just ten minutes. The sugar solution should contain not
+less than eighty nor more than 150 milligrams of the reducing sugar,
+and the quantity of the solution representing this should be diluted
+to fifty cubic centimeters before mixing with the copper solution.
+After boiling, the contents of the erlenmeyer are quickly cooled and
+filtered with suction through an asbestos filter and the whole of the
+copper suboxid washed into the filter tube. This precipitated suboxid
+is washed once with a little potassium carbonate solution then with hot
+water and finally with alcohol, well dried, heated to redness, and the
+copper oxid obtained reduced to metallic copper in an atmosphere of
+hydrogen entirely free of arsenic. From the weight of metallic copper
+obtained the quantity of sugar which has been oxidized is calculated
+from the tables below.</p>
+
+<p>It is evident that the process given above may be varied so as to
+conform to the practice observed in this laboratory of cooling the
+boiling solution sufficiently at once by adding to it an equal volume
+of recently boiled, cold water, collecting the precipitated copper
+suboxid in a gooch, and, after washing it, securing solution in nitric
+acid and the precipitation of the copper by electrolysis.
+<span class="pagenum"><a id="Page_260"></a>[Pg 260]</span></p>
+
+<p class="f120 spa1"><b><span class="smcap">Table Showing Milligrams Dextrose,<br>
+Levulose and Invert Sugar Oxidized,<br>Corresponding to Milligrams of<br>
+Copper Reduced.</span></b></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc">&nbsp; Copper. &nbsp;</th>
+      <th class="tdc">&nbsp; Dextrose. &nbsp;</th>
+      <th class="tdc">&nbsp; Levulose. &nbsp;</th>
+      <th class="tdc">&nbsp; Invert. &nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">435</td>
+      <td class="tdr_ws1">152.3</td>
+      <td class="tdr_ws1">145.9</td>
+      <td class="tdr_ws1">147.5</td>
+   </tr><tr>
+      <td class="tdc">430</td>
+      <td class="tdr_ws1">149.8</td>
+      <td class="tdr_ws1">143.4</td>
+      <td class="tdr_ws1">145.3</td>
+   </tr><tr>
+      <td class="tdc">425</td>
+      <td class="tdr_ws1">147.3</td>
+      <td class="tdr_ws1">140.9</td>
+      <td class="tdr_ws1">143.1</td>
+   </tr><tr>
+      <td class="tdc">420</td>
+      <td class="tdr_ws1">144.8</td>
+      <td class="tdr_ws1">138.4</td>
+      <td class="tdr_ws1">140.8</td>
+   </tr><tr>
+      <td class="tdc">415</td>
+      <td class="tdr_ws1">142.3</td>
+      <td class="tdr_ws1">135.9</td>
+      <td class="tdr_ws1">138.5</td>
+   </tr><tr>
+      <td class="tdc">410</td>
+      <td class="tdr_ws1">139.8</td>
+      <td class="tdr_ws1">133.5</td>
+      <td class="tdr_ws1">136.2</td>
+   </tr><tr>
+      <td class="tdc">405</td>
+      <td class="tdr_ws1">137.3</td>
+      <td class="tdr_ws1">131.1</td>
+      <td class="tdr_ws1">133.9</td>
+   </tr><tr>
+      <td class="tdc">400</td>
+      <td class="tdr_ws1">134.9</td>
+      <td class="tdr_ws1">128.7</td>
+      <td class="tdr_ws1">131.6</td>
+   </tr><tr>
+      <td class="tdc">395</td>
+      <td class="tdr_ws1">132.5</td>
+      <td class="tdr_ws1">126.4</td>
+      <td class="tdr_ws1">129.3</td>
+   </tr><tr>
+      <td class="tdc">390</td>
+      <td class="tdr_ws1">130.1</td>
+      <td class="tdr_ws1">124.1</td>
+      <td class="tdr_ws1">127.0</td>
+   </tr><tr>
+      <td class="tdc">385</td>
+      <td class="tdr_ws1">127.8</td>
+      <td class="tdr_ws1">121.8</td>
+      <td class="tdr_ws1">124.8</td>
+   </tr><tr>
+      <td class="tdc">380</td>
+      <td class="tdr_ws1">125.5</td>
+      <td class="tdr_ws1">119.5</td>
+      <td class="tdr_ws1">122.6</td>
+   </tr><tr>
+      <td class="tdc">375</td>
+      <td class="tdr_ws1">123.3</td>
+      <td class="tdr_ws1">117.2</td>
+      <td class="tdr_ws1">120.4</td>
+   </tr><tr class="bb">
+      <td class="tdc">370</td>
+      <td class="tdr_ws1">121.1</td>
+      <td class="tdr_ws1">115.0</td>
+      <td class="tdr_ws1">118.2</td>
+   </tr><tr>
+      <td class="tdc">365</td>
+      <td class="tdr_ws1">119.0</td>
+      <td class="tdr_ws1">112.8</td>
+      <td class="tdr_ws1">116.0</td>
+   </tr><tr>
+      <td class="tdc">360</td>
+      <td class="tdr_ws1">116.9</td>
+      <td class="tdr_ws1">110.6</td>
+      <td class="tdr_ws1">113.9</td>
+   </tr><tr>
+      <td class="tdc">355</td>
+      <td class="tdr_ws1">114.8</td>
+      <td class="tdr_ws1">108.5</td>
+      <td class="tdr_ws1">111.8</td>
+   </tr><tr>
+      <td class="tdc">350</td>
+      <td class="tdr_ws1">112.8</td>
+      <td class="tdr_ws1">106.4</td>
+      <td class="tdr_ws1">109.8</td>
+   </tr><tr>
+      <td class="tdc">345</td>
+      <td class="tdr_ws1">110.8</td>
+      <td class="tdr_ws1">104.3</td>
+      <td class="tdr_ws1">107.8</td>
+   </tr><tr>
+      <td class="tdc">340</td>
+      <td class="tdr_ws1">108.8</td>
+      <td class="tdr_ws1">102.3</td>
+      <td class="tdr_ws1">105.8</td>
+   </tr><tr>
+      <td class="tdc">335</td>
+      <td class="tdr_ws1">106.8</td>
+      <td class="tdr_ws1">100.3</td>
+      <td class="tdr_ws1">103.8</td>
+   </tr><tr>
+      <td class="tdc">330</td>
+      <td class="tdr_ws1">104.9</td>
+      <td class="tdr_ws1">98.4</td>
+      <td class="tdr_ws1">101.8</td>
+   </tr><tr>
+      <td class="tdc">325</td>
+      <td class="tdr_ws1">103.0</td>
+      <td class="tdr_ws1">96.5</td>
+      <td class="tdr_ws1">99.9</td>
+   </tr><tr>
+      <td class="tdc">320</td>
+      <td class="tdr_ws1">101.1</td>
+      <td class="tdr_ws1">94.6</td>
+      <td class="tdr_ws1">98.0</td>
+   </tr><tr>
+      <td class="tdc">315</td>
+      <td class="tdr_ws1">99.2</td>
+      <td class="tdr_ws1">92.8</td>
+      <td class="tdr_ws1">96.2</td>
+   </tr><tr>
+      <td class="tdc">310</td>
+      <td class="tdr_ws1">97.4</td>
+      <td class="tdr_ws1">91.0</td>
+      <td class="tdr_ws1">94.4</td>
+   </tr><tr>
+      <td class="tdc">305</td>
+      <td class="tdr_ws1">95.6</td>
+      <td class="tdr_ws1">89.2</td>
+      <td class="tdr_ws1">92.6</td>
+   </tr><tr class="bb">
+      <td class="tdc">300</td>
+      <td class="tdr_ws1">93.8</td>
+      <td class="tdr_ws1">87.5</td>
+      <td class="tdr_ws1">90.9</td>
+   </tr><tr>
+      <td class="tdc">295</td>
+      <td class="tdr_ws1">92.0</td>
+      <td class="tdr_ws1">85.8</td>
+      <td class="tdr_ws1">89.2</td>
+   </tr><tr>
+      <td class="tdc">290</td>
+      <td class="tdr_ws1">90.2</td>
+      <td class="tdr_ws1">84.1</td>
+      <td class="tdr_ws1">87.5</td>
+   </tr><tr>
+      <td class="tdc">285</td>
+      <td class="tdr_ws1">88.4</td>
+      <td class="tdr_ws1">82.4</td>
+      <td class="tdr_ws1">85.8</td>
+   </tr><tr>
+      <td class="tdc">280</td>
+      <td class="tdr_ws1">86.7</td>
+      <td class="tdr_ws1">80.8</td>
+      <td class="tdr_ws1">84.1</td>
+   </tr><tr>
+      <td class="tdc">275</td>
+      <td class="tdr_ws1">85.0</td>
+      <td class="tdr_ws1">79.2</td>
+      <td class="tdr_ws1">82.4</td>
+   </tr><tr>
+      <td class="tdc">270</td>
+      <td class="tdr_ws1">83.3</td>
+      <td class="tdr_ws1">77.6</td>
+      <td class="tdr_ws1">80.7</td>
+   </tr><tr>
+      <td class="tdc">265</td>
+      <td class="tdr_ws1">81.5</td>
+      <td class="tdr_ws1">76.1</td>
+      <td class="tdr_ws1">79.1</td>
+   </tr><tr>
+      <td class="tdc">260</td>
+      <td class="tdr_ws1">79.8</td>
+      <td class="tdr_ws1">74.6</td>
+      <td class="tdr_ws1">77.5</td>
+   </tr><tr>
+      <td class="tdc">255</td>
+      <td class="tdr_ws1">78.1</td>
+      <td class="tdr_ws1">73.1</td>
+      <td class="tdr_ws1">75.9</td>
+   </tr><tr>
+      <td class="tdc">250</td>
+      <td class="tdr_ws1">76.5</td>
+      <td class="tdr_ws1">71.6</td>
+      <td class="tdr_ws1">74.3</td>
+   </tr><tr>
+      <td class="tdc">245</td>
+      <td class="tdr_ws1">74.9</td>
+      <td class="tdr_ws1">70.1</td>
+      <td class="tdr_ws1">72.7</td>
+   </tr><tr>
+      <td class="tdc">240</td>
+      <td class="tdr_ws1">73.3</td>
+      <td class="tdr_ws1">68.6</td>
+      <td class="tdr_ws1">71.1</td>
+   </tr><tr>
+      <td class="tdc">235</td>
+      <td class="tdr_ws1">71.7</td>
+      <td class="tdr_ws1">67.2</td>
+      <td class="tdr_ws1">69.5</td>
+   </tr><tr class="bb">
+      <td class="tdc">230</td>
+      <td class="tdr_ws1">70.1</td>
+      <td class="tdr_ws1">65.7</td>
+      <td class="tdr_ws1">68.0</td>
+   </tr><tr>
+      <td class="tdc">225</td>
+      <td class="tdr_ws1">68.5</td>
+      <td class="tdr_ws1">64.3</td>
+      <td class="tdr_ws1">66.5</td>
+   </tr><tr>
+      <td class="tdc">220</td>
+      <td class="tdr_ws1">66.9</td>
+      <td class="tdr_ws1">62.8</td>
+      <td class="tdr_ws1">65.0</td>
+   </tr><tr>
+      <td class="tdc">215</td>
+      <td class="tdr_ws1">65.3</td>
+      <td class="tdr_ws1">61.4</td>
+      <td class="tdr_ws1">63.5</td>
+   </tr><tr>
+      <td class="tdc">210</td>
+      <td class="tdr_ws1">63.8</td>
+      <td class="tdr_ws1">59.9</td>
+      <td class="tdr_ws1">62.0</td>
+   </tr><tr>
+      <td class="tdc">205</td>
+      <td class="tdr_ws1">62.2</td>
+      <td class="tdr_ws1">58.5</td>
+      <td class="tdr_ws1">60.5</td>
+   </tr><tr>
+      <td class="tdc">200</td>
+      <td class="tdr_ws1">60.7</td>
+      <td class="tdr_ws1">57.0</td>
+      <td class="tdr_ws1">59.0</td>
+   </tr><tr>
+      <td class="tdc">195</td>
+      <td class="tdr_ws1">59.1</td>
+      <td class="tdr_ws1">55.6</td>
+      <td class="tdr_ws1">57.5</td>
+   </tr><tr>
+      <td class="tdc">190</td>
+      <td class="tdr_ws1">57.6</td>
+      <td class="tdr_ws1">54.1</td>
+      <td class="tdr_ws1">56.0</td>
+   </tr><tr>
+      <td class="tdc">185</td>
+      <td class="tdr_ws1">56.0</td>
+      <td class="tdr_ws1">52.7</td>
+      <td class="tdr_ws1">54.5</td>
+   </tr><tr>
+      <td class="tdc">180</td>
+      <td class="tdr_ws1">54.5</td>
+      <td class="tdr_ws1">51.2</td>
+      <td class="tdr_ws1">53.1</td>
+   </tr><tr>
+      <td class="tdc">175</td>
+      <td class="tdr_ws1">53.0</td>
+      <td class="tdr_ws1">49.8</td>
+      <td class="tdr_ws1">51.6</td>
+   </tr><tr>
+      <td class="tdc">170</td>
+      <td class="tdr_ws1">51.5</td>
+      <td class="tdr_ws1">48.4</td>
+      <td class="tdr_ws1">50.2</td>
+   </tr><tr>
+      <td class="tdc">165</td>
+      <td class="tdr_ws1">50.0</td>
+      <td class="tdr_ws1">46.9</td>
+      <td class="tdr_ws1">48.7</td>
+   </tr><tr class="bb">
+      <td class="tdc">160</td>
+      <td class="tdr_ws1">48.5</td>
+      <td class="tdr_ws1">45.5</td>
+      <td class="tdr_ws1">47.3</td>
+   </tr><tr>
+      <td class="tdc">155</td>
+      <td class="tdr_ws1">47.0</td>
+      <td class="tdr_ws1">44.1</td>
+      <td class="tdr_ws1">45.8</td>
+   </tr><tr>
+      <td class="tdc">150</td>
+      <td class="tdr_ws1">45.5</td>
+      <td class="tdr_ws1">42.7</td>
+      <td class="tdr_ws1">44.4</td>
+   </tr><tr>
+      <td class="tdc">145</td>
+      <td class="tdr_ws1">44.0</td>
+      <td class="tdr_ws1">41.3</td>
+      <td class="tdr_ws1">42.9</td>
+   </tr><tr>
+      <td class="tdc">140</td>
+      <td class="tdr_ws1">42.5</td>
+      <td class="tdr_ws1">39.9</td>
+      <td class="tdr_ws1">41.5</td>
+   </tr><tr>
+      <td class="tdc">135</td>
+      <td class="tdr_ws1">41.0</td>
+      <td class="tdr_ws1">38.5</td>
+      <td class="tdr_ws1">40.1</td>
+   </tr><tr>
+      <td class="tdc">130</td>
+      <td class="tdr_ws1">39.6</td>
+      <td class="tdr_ws1">37.1</td>
+      <td class="tdr_ws1">38.6</td>
+   </tr><tr>
+      <td class="tdc">125</td>
+      <td class="tdr_ws1">38.1</td>
+      <td class="tdr_ws1">35.7</td>
+      <td class="tdr_ws1">37.2</td>
+   </tr><tr>
+      <td class="tdc">120</td>
+      <td class="tdr_ws1">36.7</td>
+      <td class="tdr_ws1">34.3</td>
+      <td class="tdr_ws1">35.8</td>
+   </tr><tr>
+      <td class="tdc">115</td>
+      <td class="tdr_ws1">35.2</td>
+      <td class="tdr_ws1">32.9</td>
+      <td class="tdr_ws1">34.3</td>
+   </tr><tr>
+      <td class="tdc">110</td>
+      <td class="tdr_ws1">33.7</td>
+      <td class="tdr_ws1">31.6</td>
+      <td class="tdr_ws1">32.9</td>
+   </tr><tr>
+      <td class="tdc">105</td>
+      <td class="tdr_ws1">32.2</td>
+      <td class="tdr_ws1">30.3</td>
+      <td class="tdr_ws1">31.4</td>
+   </tr><tr>
+      <td class="tdc">100</td>
+      <td class="tdr_ws1">30.7</td>
+      <td class="tdr_ws1">29.0</td>
+      <td class="tdr_ws1">30.0</td>
+   </tr><tr>
+      <td class="tdc">&#8199;95</td>
+      <td class="tdr_ws1">29.2</td>
+      <td class="tdr_ws1">27.7</td>
+      <td class="tdr_ws1">28.5</td>
+   </tr><tr>
+      <td class="tdc">&#8199;90</td>
+      <td class="tdr_ws1">27.8</td>
+      <td class="tdr_ws1">26.4</td>
+      <td class="tdr_ws1">27.1</td>
+   </tr><tr>
+      <td class="tdc">&#8199;85</td>
+      <td class="tdr_ws1">26.3</td>
+      <td class="tdr_ws1">25.1</td>
+      <td class="tdr_ws1">25.6</td>
+   </tr><tr>
+      <td class="tdc">&#8199;80</td>
+      <td class="tdr_ws1">24.8</td>
+      <td class="tdr_ws1">23.8</td>
+      <td class="tdr_ws1">24.2</td>
+   </tr><tr>
+      <td class="tdc">&#8199;75</td>
+      <td class="tdr_ws1">23.3</td>
+      <td class="tdr_ws1">21.5</td>
+      <td class="tdr_ws1">22.8</td>
+   </tr><tr class="bb">
+      <td class="tdc">&#8199;70</td>
+      <td class="tdr_ws1">21.8</td>
+      <td class="tdr_ws1">20.2</td>
+      <td class="tdr_ws1">21.4
+                <span class="pagenum"><a id="Page_261"></a>[Pg 261]</span></td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="f120 spa2"><b><span class="smcap">Corresponding Table for Maltose.</span></b></p>
+
+<table class="spb1">
+   <thead><tr class="bb">
+      <th class="tdc">&nbsp; Milligrams &nbsp;<br>copper<br>obtained.</th>
+      <th class="tdc">&nbsp; Milligrams &nbsp;<br>maltose<br>anhydrid<br>oxidized.</th>
+      <th class="tdc">&nbsp; Milligrams &nbsp;<br>maltose<br>hydrate<br>oxidized.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">435</td>
+      <td class="tdc">263.7</td>
+      <td class="tdc">277.6</td>
+   </tr><tr>
+      <td class="tdc">430</td>
+      <td class="tdc">259.3</td>
+      <td class="tdc">273.0</td>
+   </tr><tr>
+      <td class="tdc">425</td>
+      <td class="tdc">255.0</td>
+      <td class="tdc">268.4</td>
+   </tr><tr>
+      <td class="tdc">420</td>
+      <td class="tdc">250.9</td>
+      <td class="tdc">264.1</td>
+   </tr><tr>
+      <td class="tdc">415</td>
+      <td class="tdc">247.0</td>
+      <td class="tdc">260.0</td>
+   </tr><tr>
+      <td class="tdc">410</td>
+      <td class="tdc">243.2</td>
+      <td class="tdc">256.0</td>
+   </tr><tr>
+      <td class="tdc">405</td>
+      <td class="tdc">339.4</td>
+      <td class="tdc">252.0</td>
+   </tr><tr>
+      <td class="tdc">400</td>
+      <td class="tdc">235.6</td>
+      <td class="tdc">248.0</td>
+   </tr><tr>
+      <td class="tdc">395</td>
+      <td class="tdc">231.9</td>
+      <td class="tdc">244.1</td>
+   </tr><tr>
+      <td class="tdc">390</td>
+      <td class="tdc">228.2</td>
+      <td class="tdc">240.2</td>
+   </tr><tr>
+      <td class="tdc">385</td>
+      <td class="tdc">224.6</td>
+      <td class="tdc">236.4</td>
+   </tr><tr>
+      <td class="tdc">380</td>
+      <td class="tdc">221.1</td>
+      <td class="tdc">232.7</td>
+   </tr><tr class="bb">
+      <td class="tdc">375</td>
+      <td class="tdc">217.7</td>
+      <td class="tdc">229.1</td>
+   </tr><tr>
+      <td class="tdc">370</td>
+      <td class="tdc">214.4</td>
+      <td class="tdc">225.6</td>
+   </tr><tr>
+      <td class="tdc">365</td>
+      <td class="tdc">211.1</td>
+      <td class="tdc">222.2</td>
+   </tr><tr>
+      <td class="tdc">360</td>
+      <td class="tdc">207.9</td>
+      <td class="tdc">218.8</td>
+   </tr><tr>
+      <td class="tdc">355</td>
+      <td class="tdc">204.7</td>
+      <td class="tdc">215.4</td>
+   </tr><tr>
+      <td class="tdc">350</td>
+      <td class="tdc">201.5</td>
+      <td class="tdc">212.1</td>
+   </tr><tr>
+      <td class="tdc">345</td>
+      <td class="tdc">198.3</td>
+      <td class="tdc">208.7</td>
+   </tr><tr>
+      <td class="tdc">340</td>
+      <td class="tdc">195.2</td>
+      <td class="tdc">205.4</td>
+   </tr><tr>
+      <td class="tdc">335</td>
+      <td class="tdc">192.0</td>
+      <td class="tdc">202.1</td>
+   </tr><tr>
+      <td class="tdc">330</td>
+      <td class="tdc">188.8</td>
+      <td class="tdc">198.8</td>
+   </tr><tr>
+      <td class="tdc">325</td>
+      <td class="tdc">185.7</td>
+      <td class="tdc">195.4</td>
+   </tr><tr>
+      <td class="tdc">320</td>
+      <td class="tdc">182.5</td>
+      <td class="tdc">192.1</td>
+   </tr><tr>
+      <td class="tdc">315</td>
+      <td class="tdc">179.4</td>
+      <td class="tdc">188.8</td>
+   </tr><tr>
+      <td class="tdc">310</td>
+      <td class="tdc">176.3</td>
+      <td class="tdc">185.6</td>
+   </tr><tr class="bb">
+      <td class="tdc">305</td>
+      <td class="tdc">173.3</td>
+      <td class="tdc">182.4</td>
+   </tr><tr>
+      <td class="tdc">300</td>
+      <td class="tdc">170.3</td>
+      <td class="tdc">179.2</td>
+   </tr><tr>
+      <td class="tdc">295</td>
+      <td class="tdc">167.3</td>
+      <td class="tdc">176.1</td>
+   </tr><tr>
+      <td class="tdc">290</td>
+      <td class="tdc">164.4</td>
+      <td class="tdc">173.0</td>
+   </tr><tr>
+      <td class="tdc">285</td>
+      <td class="tdc">161.4</td>
+      <td class="tdc">169.9</td>
+   </tr><tr>
+      <td class="tdc">280</td>
+      <td class="tdc">158.5</td>
+      <td class="tdc">166.8</td>
+   </tr><tr>
+      <td class="tdc">275</td>
+      <td class="tdc">155.5</td>
+      <td class="tdc">163.7</td>
+   </tr><tr>
+      <td class="tdc">270</td>
+      <td class="tdc">152.6</td>
+      <td class="tdc">160.7</td>
+   </tr><tr>
+      <td class="tdc">265</td>
+      <td class="tdc">149.7</td>
+      <td class="tdc">157.6</td>
+   </tr><tr>
+      <td class="tdc">260</td>
+      <td class="tdc">146.8</td>
+      <td class="tdc">154.6</td>
+   </tr><tr>
+      <td class="tdc">255</td>
+      <td class="tdc">143.9</td>
+      <td class="tdc">151.5</td>
+   </tr><tr>
+      <td class="tdc">250</td>
+      <td class="tdc">141.1</td>
+      <td class="tdc">148.5</td>
+   </tr><tr>
+      <td class="tdc">245</td>
+      <td class="tdc">138.2</td>
+      <td class="tdc">145.5</td>
+   </tr><tr>
+      <td class="tdc">240</td>
+      <td class="tdc">135.4</td>
+      <td class="tdc">142.5</td>
+   </tr><tr>
+      <td class="tdc">235</td>
+      <td class="tdc">132.5</td>
+      <td class="tdc">139.5</td>
+   </tr><tr>
+      <td class="tdc">230</td>
+      <td class="tdc">129.7</td>
+      <td class="tdc">136.5</td>
+   </tr><tr>
+      <td class="tdc">225</td>
+      <td class="tdc">126.8</td>
+      <td class="tdc">133.5</td>
+   </tr><tr>
+      <td class="tdc">220</td>
+      <td class="tdc">124.0</td>
+      <td class="tdc">130.6</td>
+   </tr><tr>
+      <td class="tdc">215</td>
+      <td class="tdc">121.2</td>
+      <td class="tdc">127.6</td>
+   </tr><tr>
+      <td class="tdc">210</td>
+      <td class="tdc">118.4</td>
+      <td class="tdc">124.7</td>
+   </tr><tr class="bb">
+      <td class="tdc">205</td>
+      <td class="tdc">115.7</td>
+      <td class="tdc">121.8</td>
+   </tr><tr>
+      <td class="tdc">200</td>
+      <td class="tdc">112.9</td>
+      <td class="tdc">118.9</td>
+   </tr><tr>
+      <td class="tdc">195</td>
+      <td class="tdc">110.2</td>
+      <td class="tdc">116.0</td>
+   </tr><tr>
+      <td class="tdc">190</td>
+      <td class="tdc">107.4</td>
+      <td class="tdc">113.1</td>
+   </tr><tr>
+      <td class="tdc">185</td>
+      <td class="tdc">104.7</td>
+      <td class="tdc">110.2</td>
+   </tr><tr>
+      <td class="tdc">180</td>
+      <td class="tdc">101.9</td>
+      <td class="tdc">107.3</td>
+   </tr><tr>
+      <td class="tdc">175</td>
+      <td class="tdc">&#8199;99.2</td>
+      <td class="tdc">104.4</td>
+   </tr><tr>
+      <td class="tdc">170</td>
+      <td class="tdc">&#8199;96.4</td>
+      <td class="tdc">101.5</td>
+   </tr><tr>
+      <td class="tdc">165</td>
+      <td class="tdc">&#8199;93.7</td>
+      <td class="tdc">&#8199;98.6</td>
+   </tr><tr>
+      <td class="tdc">160</td>
+      <td class="tdc">&#8199;90.9</td>
+      <td class="tdc">&#8199;95.7</td>
+   </tr><tr>
+      <td class="tdc">155</td>
+      <td class="tdc">&#8199;88.2</td>
+      <td class="tdc">&#8199;92.8</td>
+   </tr><tr>
+      <td class="tdc">150</td>
+      <td class="tdc">&#8199;85.4</td>
+      <td class="tdc">&#8199;89.9</td>
+   </tr><tr>
+      <td class="tdc">145</td>
+      <td class="tdc">&#8199;82.6</td>
+      <td class="tdc">&#8199;87.0</td>
+   </tr><tr>
+      <td class="tdc">140</td>
+      <td class="tdc">&#8199;79.9</td>
+      <td class="tdc">&#8199;84.1</td>
+   </tr><tr>
+      <td class="tdc">135</td>
+      <td class="tdc">&#8199;77.1</td>
+      <td class="tdc">&#8199;81.2</td>
+   </tr><tr>
+      <td class="tdc">130</td>
+      <td class="tdc">&#8199;74.4</td>
+      <td class="tdc">&#8199;78.3</td>
+   </tr><tr>
+      <td class="tdc">125</td>
+      <td class="tdc">&#8199;71.6</td>
+      <td class="tdc">&#8199;75.4</td>
+   </tr><tr>
+      <td class="tdc">120</td>
+      <td class="tdc">&#8199;68.9</td>
+      <td class="tdc">&#8199;72.5</td>
+   </tr><tr>
+      <td class="tdc">115</td>
+      <td class="tdc">&#8199;66.1</td>
+      <td class="tdc">&#8199;69.6</td>
+   </tr><tr>
+      <td class="tdc">110</td>
+      <td class="tdc">&#8199;63.4</td>
+      <td class="tdc">&#8199;66.7</td>
+   </tr><tr class="bb">
+      <td class="tdc">105</td>
+      <td class="tdc">&#8199;60.6</td>
+      <td class="tdc">&#8199;63.8</td>
+   </tr><tr>
+      <td class="tdc">100</td>
+      <td class="tdc">&#8199;57.9</td>
+      <td class="tdc">&#8199;60.9</td>
+   </tr><tr>
+      <td class="tdc">&#8199;95</td>
+      <td class="tdc">&#8199;55.1</td>
+      <td class="tdc">&#8199;58.0</td>
+   </tr><tr>
+      <td class="tdc">&#8199;90</td>
+      <td class="tdc">&#8199;52.3</td>
+      <td class="tdc">&#8199;55.1</td>
+   </tr><tr>
+      <td class="tdc">&#8199;85</td>
+      <td class="tdc">&#8199;49.6</td>
+      <td class="tdc">&#8199;52.2</td>
+   </tr><tr>
+      <td class="tdc">&#8199;80</td>
+      <td class="tdc">&#8199;46.8</td>
+      <td class="tdc">&#8199;59.3</td>
+   </tr><tr>
+      <td class="tdc">&#8199;75</td>
+      <td class="tdc">&#8199;44.1</td>
+      <td class="tdc">&#8199;56.4</td>
+   </tr><tr class="bb">
+      <td class="tdc">&#8199;70</td>
+      <td class="tdc">&#8199;41.4</td>
+      <td class="tdc">&#8199;53.5</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_262"></a>[Pg 262]</span>
+<b>235. Weighing the Copper as Oxid.</b>—In the usual methods of the
+determination of reducing bodies, the percentage is calculated either
+volumetrically from the quantity of the sugar solution required to
+decolorize a given volume of the alkaline copper solution, or the
+reduced copper suboxid is brought into a metallic state by heating in
+an atmosphere of hydrogen or by electrolytic deposition. A quicker
+method of procedure is found in completing the oxidation of the cupric
+oxid by heating to low redness in a current of air.<a id="FNanchor_192" href="#Footnote_192" class="fnanchor">[192]</a> For this
+determination the precipitation of the cuprous oxid and its filtration
+are made in the usual manner. The cuprous oxid is collected in a
+filtering tube, made by drawing out to proper dimensions a piece of
+combustion tube, and has a length of about twelve centimeters in all.
+The unchanged part of the tube is about eight centimeters in length
+and twelve millimeters in diameter. It is filled by first putting in
+a plug of glass wool and covering this with an asbestos felt on top
+of which another plug of glass wool is placed. After the cuprous oxid
+is collected in the tube it is washed with boiling water, alcohol and
+ether. The rubber tube connecting it with the suction is of sufficient
+length to permit the tube being taken in one hand and brought into
+a horizontal position over a bunsen. The tube is gradually heated,
+rotating it meanwhile, until any residual moisture, alcohol or ether,
+is driven off from the filtering material. The layer of glass wool
+holding the cuprous oxid is gradually brought into the flame and as
+the oxidation begins the material will be seen to glow. The heating is
+continued for some time after the glowing has ceased, in all for three
+or four minutes, the tube and the copper oxid which it contains being
+brought to a low redness. The current of air passing over the red-hot
+material in this time oxidizes it completely. The filtering tube,
+before use, must be ignited and weighed in exactly the same manner as
+described above. The heat is so applied as not to endanger the rubber
+tube attached to one end of the filtering tube nor to burn the fingers
+of the operator as he turns the tube during the heating. After complete
+oxidation the tube is cooled in a desiccator and weighed, the increase
+of weight giving the copper oxid. For the atomic weights, 63.3 copper
+<span class="pagenum"><a id="Page_263"></a>[Pg 263]</span>
+and 15.96 oxygen, one gram of copper oxid is equivalent to 0.79864
+gram of copper, and for the weights 63.17 copper and 15.96 oxygen, one
+gram of copper oxid equals 0.79831 gram of copper. From the amount of
+metallic copper calculated by one of these factors, the reducing sugar
+is determined by the tables already given.</p>
+
+<p><b>236. Estimation of Dry Substance, Polarization and Apparent Purity
+for Factory Control.</b>—For technical purposes the methods of
+determining the above factors, proposed by Weisberg and applicable to
+concentrated sirups, massecuites, and molasses, may be used.<a id="FNanchor_193" href="#Footnote_193" class="fnanchor">[193]</a>
+Five times the half normal quantity of the material, <i>viz.</i>, 65.12
+grams, are placed in a quarter liter flask, dissolved in water and the
+flask filled to the mark. In the well shaken mixture, which is allowed
+to stand long enough to be free of air, the degree brix is estimated
+by an accurate spindle. For example, in the case of molasses, let the
+number obtained be 18.8.</p>
+
+<p>Fifty cubic centimeters of the solution are poured into a 100 cubic
+centimeter flask, the proper quantity of lead subacetate added, the
+flask filled to the mark with water, its contents filtered, and the
+filtrate polarized in a 200 millimeter tube. Let the number obtained on
+polarization be 22°.1. This number may be used in two ways. If it be
+multiplied by two the polarization of the original sample is obtained;
+in this case, <i>viz.</i>, 44°.2. In the second place, if 44.2 be
+multiplied by 0.26048 and this product divided by the specific gravity
+corresponding to 18°.8. <i>viz.</i>, 1.078, the quotient 10.68 is
+secured representing the polarization or per cent of sugar contained in
+the solution of which the degree brix was 18.8°. From the numbers 18.8
+and 10.68 the apparent purity of the solution, 56.8, is calculated,
+<i>viz.</i>, 10.68 × 100 ÷ by 18.8. The original product as calculated
+above gives a polarization of 44.2 and this number multiplied by 100
+and divided by 56.8 gives 77.8, or the apparent percentage of dry
+matter. The original sample of molasses, therefore, had the following
+composition:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Degree brix (total solids)&emsp;&nbsp;</td>
+      <td class="tdc"> 77.8</td>
+      <td class="tdl_wsp">per cent.</td>
+   </tr><tr>
+      <td class="tdl">Sucrose</td>
+      <td class="tdc">44.2</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl">Solids, not sucrose</td>
+      <td class="tdc">33.6</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl">Apparent purity</td>
+      <td class="tdc">56.8</td>
+      <td class="tdc">”</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_264"></a>[Pg 264]</span>
+It is seen from the above that with a single weighing and a single
+polarization, and within from ten to fifteen minutes, all needful
+data in respect of the proper treatment of molasses for the practical
+control and direction of a factory can be obtained.</p>
+
+<p>In case a laurent polariscope is used, five times the normal weight,
+<i>viz.</i>, eighty-one grams of the raw material are used and the
+process conducted as above.</p>
+
+<h3>SUCROSE, DEXTROSE, INVERT SUGAR, LEVULOSE,<br> MALTOSE,
+RAFFINOSE, DEXTRIN AND<br> LACTOSE IN MIXTURES.</h3>
+
+<p id="P_237"><b>237. Occurrence.</b>—Sucrose and invert sugar are found together in
+many commercial products, especially in raw sugars and molasses made
+from sugar cane, and in these products sucrose is usually predominant.
+They also form the principal saccharine contents of honey, the invert
+sugar, in this case, being the chief ingredient.</p>
+
+<p>In commercial grape sugar, made from starch, dextrose is the important
+constituent, while in the hydrolysis of starch by a diastatic ferment,
+maltose is principally produced. In the manufacture of commercial
+glucose by the saccharification of starch with sulfuric acid, dextrin,
+maltose, and dextrose are the dominant products, while in the similar
+substance midzu ame, maltose and dextrose are chiefly found, and only a
+small quantity of dextrose.<a id="FNanchor_194" href="#Footnote_194" class="fnanchor">[194]</a>
+In honeys derived from the exudations of coniferous trees are found
+also polarizing bodies not enumerated above and presumably of a pentose
+character.<a id="FNanchor_195" href="#Footnote_195" class="fnanchor">[195]</a>
+In evaporated milks are usually found large quantities of sucrose
+in addition to the natural sugar therein contained. These mixtures
+of carbohydrates often present problems of great difficulty to the
+analyst, and the following paragraphs will be devoted to an elucidation
+of the best approved methods of solving them.</p>
+
+<h3>OPTICAL METHODS.</h3>
+
+<p id="P_238"><b>238. Sucrose and Invert Sugar.</b>—The chemical methods of
+procedure to be followed in the case of a sample containing both
+sucrose and invert sugar have been given in sufficient detail in
+preceding paragraphs (<b><a href="#P_124">124</a>, <a href="#P_171">171</a></b>).
+<span class="pagenum"><a id="Page_265"></a>[Pg 265]</span>
+When, however, it is desirable to study further the composition of
+the mixture, important changes in the method are rendered imperative.
+While the estimation of the sucrose and the total invert sugar, or
+the sum of the dextrose and levulose, is easy of accomplishment the
+separate determination of the dextrose and levulose is not so readily
+secured. In the latter case the total quantity of the two sugars may
+be determined, and after the destruction or removal of one of them the
+other be estimated in the usual way; or in the mixture the levulose can
+be determined by the variation in its gyrodynat, caused by changes of
+temperature.</p>
+
+<p><b>239. Optical Neutrality of Invert Sugar.</b>—The gyrodynat of
+levulose decreases as the temperature rises (<b><a href="#P_107">107</a></b>) and at or
+near a temperature of 87°.2, it becomes equal to that of dextrose,
+and, therefore, pure invert sugar composed of equal molecules of
+levulose and dextrose is optically neutral to polarized light at that
+temperature. On this fact Chandler and Ricketts have based a method of
+analysis which excludes any interference in polarization due to invert
+sugar.<a id="FNanchor_196" href="#Footnote_196" class="fnanchor">[196]</a>
+To secure the polarization at approximately a temperature
+of 87°, a water-bath is placed between the nicols of an ordinary
+polariscope in such a way as to hold a tubulated observation tube
+in the optical axis of the instrument. The ends of the bath, in the
+prolongation of this axis, are provided with clear glass disks. The
+space between the cover glasses of the observation tube and the glass
+disks of the bath is occupied by the water of the bath. When this is
+kept at a constant temperature it does not interfere with the reading.
+The observation tube may be of glass, but preferably is constructed of
+metal plated with platinum on the inside. For the most exact work the
+length of the observation tube, at 87°, is determined by measurement or
+calculation. The bath is heated with alcohol lamps or other convenient
+means. The arrangement of the apparatus is shown in <a href="#FIG_75B">Fig. 75</a>.</p>
+
+<p>In a mixture of sucrose and invert sugar any rotation of the plane
+of polarized light at 87° is due to the sucrose alone. In a mixture
+of dextrose and sucrose the polarization is determined, and, after
+inversion, again determined at 87°. The latter number is due to
+dextrose alone, and the difference between the two gives the rotation
+due to sucrose.
+<span class="pagenum"><a id="Page_266"></a>[Pg 266]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_75B" src="images/fig75_2.jpg" alt="" width="400" height="462" >
+    <p class="center spb1">Fig. 75.—Chandler and Ricketts’ Polariscope.</p>
+</div>
+
+<p><b>240. Sucrose and Raffinose.</b>—In raw sugars made from beet
+molasses considerable quantities of raffinose are found. The method
+of inversion and polarization in such cases is described in paragraph
+<b><a href="#P_100">100</a></b>. In making the inversion by the method proposed by Lindet
+(<b><a href="#P_95">95</a></b>), and conducting the polarization on a laurent instrument, a
+slightly different formula, given below, is used; <i>viz.</i>:</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdr" rowspan="2"><i>S</i> = &nbsp;</td>
+      <td class="tdc bb"><i>C</i> - 0.4891<i>A</i></td>
+   </tr><tr>
+      <td class="tdc">0.810</td>
+   </tr><tr>
+      <td class="tdc" colspan="2">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl" rowspan="2">and&emsp;<i>R</i> = &nbsp;</td>
+      <td class="tdc bb"><i>A</i> - <i>S</i></td>
+   </tr><tr>
+      <td class="tdc">1.54</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_267"></a>[Pg 267]</span>
+in which the several letters refer to the same factors as are indicated
+by them in the formula of Creydt. In the application of the formula
+just given the normal weight of the mixed raw sugars used is 16.2
+grams.<a id="FNanchor_197" href="#Footnote_197" class="fnanchor">[197]</a></p>
+
+<p><b>241. Optical Determination of Levulose.</b>—The determination of
+levulose by optical methods alone is made possible by reason of the
+fact that the gyrodynats of the sugars with which it is associated are
+not sensibly affected by changes of temperature. The principle of the
+process, as developed by the author, rests on the ascertainment of the
+change in the gyrodynat of levulose when its rotation is observed at
+widely separated temperatures.<a id="FNanchor_198" href="#Footnote_198" class="fnanchor">[198]</a>
+The observation tube employed for reading at low temperatures is
+provided with desiccating end tubes, which prevent the deposition of
+moisture on the cover glasses. The relations of this device to the
+optical parts of the apparatus are illustrated in <a href="#FIG_76">Fig. 76</a>.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_76" src="images/fig76.jpg" alt="" width="600" height="320" >
+    <p class="center spb1">Fig. 76.—Apparatus for Polarimetric Observations<br>
+            at Low Temperatures.</p>
+</div>
+
+<p>The protecting tubes are made of hard rubber and the desiccation is
+secured by surrounding the space between the rubber and the perforated
+metal axis with fragments of potash or calcium chlorid.</p>
+
+<p>The details of the construction are shown in a horizontal section
+through the center of the observation tube in <a href="#FIG_77">Fig. 77</a>. In this figure
+<span class="pagenum"><a id="Page_268"></a>[Pg 268]</span>
+the observation tube, made of glass or metal, is represented by
+<i>i</i>, the metal jacket, open at the top in the <b>V</b> shape as
+described, by <i>k</i>. The observation tube is closed by the heavy
+disk <i>b</i> made of non-polarizing glass. This disk is pressed
+against the end of the observation tube by the rubber washer <i>a</i>,
+when the drying system about to be described is screwed on to <i>k</i>.
+The apparatus for keeping the cover glass dry is contained in the
+hard rubber tube <i>m</i> and consists of a perforated cylinder of
+brass <i>e</i>, supported at one end by the perforated disk <i>c</i>
+and at the outer ends by the arms <i>d</i>. It is closed by a cover
+glass of non-polarizing glass <i>s</i> and can be screwed on to the
+system <i>h</i> at <i>n</i>. The space <i>p</i> is filled with coarse
+fragments of caustic soda, potash, or calcium chlorid by removing the
+cover glass <i>s</i>. The perforated disk <i>c</i> prevents any of the
+fragments from entering the axis of observation. When the cover glass
+<i>s</i> is replaced, it just touches the free end of the perforated
+metal tube preventing any of the fragments of the drying material from
+falling into the center at the outer end. When this drying tube is
+placed in position, the contents of the observation tube <i>i</i> can
+be kept at the temperature of zero for an indefinite time without the
+deposition of a particle of moisture either upon the glass <i>b</i> or <i>s</i>.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_77" src="images/fig77.jpg" alt="" width="600" height="318" >
+    <p class="center spb1">Fig. 77.—Construction of Desicating Tube.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_269"></a>[Pg 269]</span>
+For determining the rotation at a high temperature the apparatus of
+Chandler and Ricketts (<b><a href="#P_238">238</a></b>) may be used or the following device:
+The polarizing apparatus shown above, <a href="#FIG_76">Fig. 76</a>, may be used
+after the <b>V</b> shape box is removed from the stand, which is so constructed
+as to receive a large box covered with asbestos felt an inch thick. The
+observation tube is held within this box in the same way as in the one
+just described so that the hot water extends not only the entire length
+of the tube but also covers the cover glasses. In both cases the cover
+glasses are made of heavier glass and are much larger in diameter than
+found in the ordinary tubes for polariscopes. The protecting cylinders
+of hard rubber are not needed at high temperatures but can be left on
+without detriment.</p>
+
+<p>The illustration, <a href="#FIG_78">Fig. 78</a>, shows the
+arrangement of the apparatus with a silver tube in position, which can
+be filled and emptied without removing it.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_78" src="images/fig78.jpg" alt="" width="600" height="408" >
+    <p class="center spb1">Fig. 78.—Apparatus for Polarizing<br> at High Temperatures.</p>
+</div>
+
+<p>In practice the water is heated with a jet of steam and an even
+temperature is secured by a mechanical stirrer kept slowly in motion.
+<span class="pagenum"><a id="Page_270"></a>[Pg 270]</span>
+With such a box it is easy to maintain a temperature for several
+hours which will not vary more than half a degree. The temperature
+for reading the hot solutions was fixed at 88°, this being nearly the
+temperature at which a mixture of equal molecules of levulose and
+dextrose is optically inactive. In every case the sugar solutions were
+made up to the standard volume at the temperatures at which they were
+to be read and thus the variations due to expansion or contraction
+were avoided. When solutions are read at a high temperature, they must
+be made with freshly boiled water so as to avoid the evolution of air
+bubbles which may otherwise obscure the field of vision.</p>
+
+<p>By means of the apparatus described it is easy for the analyst to make
+a polarimetric reading at any temperature desired. In all cases the
+observation tube should be left at least a half an hour and sometimes
+longer in contact with the temperature control media before the reading
+is made.</p>
+
+<p>The appearance of the field of vision is usually a pretty fair index
+of the point of time at which a constant temperature is established
+throughout all parts of the system. Any variation in temperature
+produces a distortion of the field of vision while a constant fixed
+temperature will disclose the field of vision in its true shape and
+distinctness of outline.</p>
+
+<p><i>Principles of the Calculation.</i>—If 26.048 grams of pure sucrose
+be dissolved in water and the volume made 100 cubic centimeters, it
+will produce an angular rotation of 34°.68 when examined in a 200
+millimeter tube with polarized sodium monochromatic light. Upon the
+cane sugar scale of an accurately graduated shadow instrument the
+reading will be 100 divisions corresponding to 100 per cent of pure
+sucrose.</p>
+
+<p>In the complete inversion of the cane sugar the reaction which takes
+place is represented by the following formula:</p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&#8212;</td>
+      <td class="tdc">+</td>
+   </tr><tr>
+      <td class="tdr_wsp">C₁₂H₂₂O₁₁ +</td>
+      <td class="tdr_wsp">H₂0 =</td>
+      <td class="tdr_wsp">C₆H₁₂O₆ +</td>
+      <td class="tdl">C₆H₁₂O₆.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The minus and plus signs indicate that the resulting invert sugar is
+a mixture of equal parts of levulose (<i>d</i> fructose) and dextrose
+(<i>d</i> glucose). We are not concerned here with the fact that a
+complete inversion of cane sugar is a matter of great difficulty nor
+<span class="pagenum"><a id="Page_271"></a>[Pg 271]</span>
+with the danger which is always experienced of destroying a part of
+one of the products of inversion. They are matters which may cause
+a variation in the analytical data afterward, but do not affect the
+principles on which the process is based.</p>
+
+<p>In the inversion of 26.048 grams of cane sugar there are therefore
+produced 13.71 grams of levulose and 13.71 grams of dextrose or, in
+all, 27.42 grams of the mixed sugars.</p>
+
+<p>The angular rotation which would be produced by 13.71 grams of
+dextrose in a volume of 100 cubic centimeters and through a column 200
+millimeters in length is, with sodium light, 14°.53 equivalent to 41.89
+divisions of the cane sugar scale. The specific rotatory power of a
+dextrose solution of the density given is almost exactly 53, and this
+number is used in the calculations.</p>
+
+<p>In a mixture of the two sugars under the conditions mentioned and at a
+temperature of 0° the angular rotation observed is -15°.15 equivalent
+to 43.37 divisions of the cane sugar scale.</p>
+
+<p>The + rotation due to the dextrose is 14°.53. Therefore the total
+negative rotation due to levulose at 0° is 15°.15 + 14°.53 =
+29°.68. Hence the gyrodynat of levulose at 0° and in the degree of
+concentration noted is readily calculated from the formula</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">[α]°<span class="fs_80"><sub>D</sub></span> = -&nbsp;</td>
+      <td class="tdc bb">29.68 × 100</td>
+      <td class="tdl_wsp" rowspan="2">= -108.24.</td>
+   </tr><tr>
+      <td class="tdc">2 × 13.71</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Since at 88° (<i>circa</i>) the mixture of levulose and dextrose is
+neutral to polarized light, it follows that at that temperature the
+specific rotatory power of levulose is equal to that of dextrose,
+<i>viz.</i>, 53°.</p>
+
+<p class="f105">[α]<span class="fs_80"><sub>D</sub></span>⁸⁸ ° = - 53°.</p>
+
+<p>The total variation in the specific rotatory power of levulose, between
+zero and 88°, is 55°.24. The variation for each degree of temperature,
+therefore, of the specific rotatory power of levulose is equal to
+55.24 divided by 88, which is equal to 0.628. From these data it is
+easy to calculate the specific rotatory power of levulose for any
+given temperature. For instance, let it be required to determine the
+<span class="pagenum"><a id="Page_272"></a>[Pg 272]</span>
+gyrodynat of levulose at a temperature of 20°. It will be found equal
+to 108.24 - 0.628 × 20 = 95.68. The required rotatory power is then
+[<i>a</i>]²⁰ °<span class="fs_80"><sub>D</sub></span> = -95°.68.</p>
+
+<p>In these calculations the influence of the presence of hydrochloric
+acid upon the rotatory power of the levulose is neglected.</p>
+
+<p>Since the variation in angular rotation in the mixture at different
+temperatures is due almost wholly to the change in this property of the
+levulose it follows that the variation for each degree of temperature
+and each per cent of levulose can be calculated. Careful experiments
+have shown that the variation in the rotatory power of levulose between
+0° and 88° is represented by a straight line. For 13.71 grams per
+100 cubic centimeters the variation for each degree of temperature
+is equal to 43.37 ÷ 88 = 0.49 divisions on the cane sugar scale, or
+15.15 ÷ 88 = 0°.1722 angular measure. If 13.71 grams of levulose in
+100 cubic centimeters produce the deviations mentioned for each degree
+of temperature, one gram would give the deviation obtained by the
+following calculations:</p>
+
+<p>For the cane sugar scale 0.49 ÷ 13.71 = 0°.0357 and for angular
+rotation 0.1722 ÷ 13.71 = 0.01256.</p>
+
+<p>The above data afford a simple formula for calculating the percentage
+of levulose present from the variation observed in polarizing a
+solution containing levulose, provided that the quantity of levulose
+present is approximately fourteen grams per 100 cubic centimeters.</p>
+
+<p class="blockquot"><i>Example.</i>—Suppose in a given case the
+difference of reading between a solution containing an unknown quantity
+of levulose at 0° and 88° is equal to thirty divisions of the cane
+sugar scale. What weight of levulose is present? We have already seen
+that one gram in 100 cubic centimeters produces a variation of 0.0357
+division for 1°. For 88° this would amount to 3.1416 divisions. The
+total weight of levulose present is therefore 30 ÷ 3.1416 = 9.549
+grams. In the case given 26.048 grams of honey were taken for the
+examination. The percentage of levulose was therefore 9.549 × 100 ÷
+26.048 = 36.66 per cent.</p>
+
+<p>If it be inconvenient to determine the polarimetric observations at
+<span class="pagenum"><a id="Page_273"></a>[Pg 273]</span>
+temperatures so widely separated as 0° and 88° the interval may be
+made less. In the above case if the readings had been made at 20° and
+70° the total variation would have been only ⁵⁰/⁸⁸ of the one given,
+<i>viz.</i>, 17.05 divisions of the cane sugar scale. The calculation
+would then have proceeded as follows:</p>
+
+<p class="f105">0.0357 × 50 = 1.785.</p>
+
+<p>Then, 17.05 ÷ 1.785 = 9.552 grams of levulose, from which the actual
+percentage of levulose can be calculated as above.</p>
+
+<p>With honeys the operation is to be conducted as follows:</p>
+
+<p>Since honeys contain approximately twenty per cent of water and in the
+dry substance have approximately forty-five per cent of levulose, about
+38.50 grams of the honey should be taken to get approximately 13.8
+grams of levulose.</p>
+
+<p>In the actual determination the calculations may be based on
+the factors above noted, but without respect to the degree of
+concentration. If half the quantity of dextrose noted be present its
+specific rotatory power is only reduced to about 52°.75, and this will
+make but little difference in the results. In the case of honey 13.024
+grams of the sample are conveniently used in the examination, half the
+normal weight for the ventzke sugar scale. The error, however, due to
+difference in concentration is quite compensated for by the ease of
+clarification and manipulation. Alumina cream alone is used in the
+clarification, thus avoiding the danger of heating the solution to a
+high temperature in the presence of an excess of lead acetate.</p>
+
+<p>An interesting fact is observed in cooling solutions of honey to
+0°. The maximum left hand rotation is not reached as soon as the
+temperature reaches 0° but only after it has been kept at that
+temperature for two or three hours. The line representing the change in
+rotatory power in solutions of honey between 10° and 88° is practically
+straight but from 10° to 0°, if measured by the readings taken without
+delay, it is decidedly curved; the reading being less at first than
+it is afterwards. After three hours the 0° becomes sensibly constant
+and then the whole line is nearly straight, but still with a slight
+deficiency in the reading at the 0°. For this reason the computations
+should be based on readings between 10° and 88° rather than on a number
+<span class="pagenum"><a id="Page_274"></a>[Pg 274]</span>
+covering the whole range of temperature. Nevertheless, if the solution
+be kept at 10° for three hours before the final reading is taken, no
+error of any practical magnitude is introduced.</p>
+
+<p>The calculations given above, for the cane sugar scale, can also be
+made in an exactly similar manner for angular rotation. The angular
+variation produced by one gram of levulose for 1° of temperature
+is 0°.01256. For 88° this would become 1°.10528. Suppose the total
+observed angular deviation in a given case between 0° and 88° to be
+10°.404, then the weight of levulose present is 10.404 ÷ 1.10528 = 9.413 grams.</p>
+
+<p>In the case mentioned 26.048 grams of honey were taken for the
+examination. The percentage of levulose present, therefore, was
+9.413 × 100 ÷ 26.048 = 36.13.</p>
+
+<p><b>241. General Formula for the Calculation of Percentage of
+Levulose.</b>—Let <i>K</i> = deviation in divisions of the cane sugar
+scale or in angular rotation produced by one gram of levulose for 1°
+temperature.</p>
+
+<div class="blockquot">
+<p>Let <i>T</i> and <i>tʹ</i> = temperatures at which observations are made.</p>
+
+<p>Let <i>R</i> = observed deviation in rotation.</p>
+
+<p>Let <i>W</i> = weight of levulose obtained.</p>
+
+<p>Let <i>L</i> = per cent of levulose required.</p>
+</div>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">Then&emsp;<i>L</i> =&nbsp;</td>
+      <td class="tdc bb"><i>R</i></td>
+      <td class="tdl_wsp" rowspan="2">÷ <i>W</i>.</td>
+   </tr><tr>
+      <td class="tdc"><i>K</i>(<i>T</i> - <i>tʹ</i>)</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>In most genuine honeys the value of <i>R</i> between 0° and 88° is
+approximately thirty divisions of the cane sugar scale or 10° angular
+measure for 26.048 grams in 100 cubic centimeters, read in a 200
+millimeter tube, or, for 13.024 grams in 100 cubic centimeters read in
+a 400 millimeter tube.</p>
+
+<p>The method of analysis outlined above has been applied in the
+examination of a large number of honeys with most satisfactory results.
+It can also be applied with equal facility to other substances
+containing levulose.</p>
+
+<p><b>242. Sucrose and Dextrose.</b>—In mixtures these two sugars are
+easily determined by optical processes, provided no other bodies
+sensibly affecting the plane of polarized light be present. The total
+<span class="pagenum"><a id="Page_275"></a>[Pg 275]</span>
+deviation due to both sugars is determined in the usual way. The
+percentage of sucrose is afterwards found by the inversion method
+(<b><a href="#P_92">92</a></b>). The rotation, in the first instance due to the sucrose,
+is calculated from the amount of this body found by inversion, and
+the residual rotation is caused by the dextrose. The percentage of
+dextrose is easily calculated by a simple proportion into which the
+numbers expressing the gyrodynats of sucrose and dextrose enter. When
+the readings are made on a ventzke scale the calculations are made as
+follows:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Weight of sample used</td>
+      <td class="tdr">26.048</td>
+      <td class="tdl_top" rowspan="6">&nbsp;grams.</td>
+   </tr><tr>
+      <td class="tdl">First polarization</td>
+      <td class="tdr_wsp">88°.5</td>
+   </tr><tr>
+      <td class="tdl">Polarization after inversion &nbsp;</td>
+      <td class="tdr_wsp">10°.5</td>
+   </tr><tr>
+      <td class="tdl">Temperature</td>
+      <td class="tdr_wsp">20°.0</td>
+   </tr><tr>
+      <td class="tdl">Percentage of sucrose</td>
+      <td class="tdr_wsp">58.4</td>
+   </tr><tr>
+      <td class="tdl">Rotation due to dextrose</td>
+      <td class="tdr_wsp">30°.1</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Percentage of dextrose:</p>
+
+<p class="f105">66.5 : 53 = <i>x</i> : 30.1;&emsp;whence <i>x</i> = 37.8.</p>
+
+<p>The sample examined therefore contains 58.4 per cent of sucrose and
+37.8 per cent of dextrose.</p>
+
+<p>It is evident that the method just described is also applicable when
+maltose, dextrin, or any other sugar or polarizing body, not sensibly
+affected by the process of inversion to which the sucrose is subjected,
+is substituted for dextrose. When, however, more than two optically
+active bodies are present the purely polariscopic process is not
+applicable. In such cases the chemical or the combined chemical and
+optical methods described further on can be employed.</p>
+
+<p id="P_243"><b>243. Lactose in Milk.</b>—By reason of its definite gyrodynat
+lactose in milk is quickly and accurately determined by optical
+methods, when proper clarifying reagents are used to free the fluid
+of fat and nitrogenous substances. Soluble albuminoids have definite
+levogyratory powers and, if not entirely removed, serve to diminish the
+rotation due to the lactose.</p>
+
+<p>Milk casein precipitated by magnesium sulfate has the following
+gyrodynatic numbers assigned to it:<a id="FNanchor_199" href="#Footnote_199" class="fnanchor">[199]</a></p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Dissolved</td>
+      <td class="tdr">&nbsp;in&nbsp;</td>
+      <td class="tdl_wsp">water [<i>a</i>]<span class="fs_80"><sub>D</sub></span> = -80°</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">very dilute solution [<i>a</i>]<span class="fs_80"><sub>D</sub></span> = -87°.</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">dilute sodium hydroxid solution [<i>a</i>]<span class="fs_80"><sub>D</sub></span> = -76°.</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">strong potassium hydroxid solution [<i>a</i>]<span class="fs_80"><sub>D</sub></span> = -91°.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_276"></a>[Pg 276]</span>
+The hydrates of albumen have rotation powers which vary from
+[<i>a</i>]<sub>D</sub> = -71°.40 to [<i>a</i>]<sub>D</sub> = -79°-05. From the chaotic
+state of knowledge concerning the specific rotating power of the
+various albumens, it is impossible to assign any number which will
+bear the test of criticism. For the present, however, this number may
+be fixed at [<i>a</i>]<span class="fs_80"><sub>D</sub></span> = -70° for the albumens which remain in
+solution in the liquids polarized for milk sugar.<a id="FNanchor_200" href="#Footnote_200" class="fnanchor">[200]</a></p>
+
+<p>Many reagents have been prepared for the removal of the disturbing
+bodies from milk in order to make its polarization possible. Among
+the precipitants which have been used in this laboratory may be
+mentioned:<a id="FNanchor_201" href="#Footnote_201" class="fnanchor">[201]</a></p>
+
+<div class="blockquot">
+<p>(1) Saturated solution basic lead acetate, specific gravity 1.97:</p>
+
+<p>(2) Nitric acid solution of mercuric nitrate diluted with an equal
+volume of water: (<b><a href="#P_88">88</a>.</b>)</p>
+
+<p>(3) Acetic acid, specific gravity 1.040, containing twenty-nine per
+cent acetic acid:</p>
+
+<p>(4) Nitric acid, specific gravity 1.197, containing thirty per cent
+nitric acid:</p>
+
+<p>(5) Sulfuric acid, specific gravity 1.255, containing thirty-one per
+cent sulfuric acid:</p>
+
+<p>(6) Saturated solution of sodium chlorid:</p>
+
+<p>(7) Saturated solution of magnesium sulfate:</p>
+
+<p>(8) Solution of mercuric iodid in acetic acid, formula; potassium
+iodid, 33.2 grams; mercuric chlorid, 13.5 grams; strong acetic acid,
+20.0 cubic centimeters; water 640 cubic centimeters.</p>
+</div>
+
+<p>Alcohol, ether, and many solutions of mineral salts, hydrochloric and
+other acids are also used as precipitants for albumen, but none of them
+presents any advantages.</p>
+
+<p>Experience has shown that the best results in polariscopic work are
+secured by the use of either the mercuric iodid or the acid mercuric
+nitrate for clarifying the milk. The latter reagent should be used
+in quantities of about three cubic centimeters for each 100 of milk.
+It is evident when it is desired to determine the residual nitrogen
+in solution, the former reagent must be employed. The quantity of
+albuminoid matter left in solution after clarification with mercurial
+salts is so minute as to exert no sensible effect on the rotation of
+the plane of polarized light produced by the lactose.
+<span class="pagenum"><a id="Page_277"></a>[Pg 277]</span></p>
+
+<p>For purposes of calculation the gyrodynat of lactose in the ordinary
+conditions of temperature and concentration may be represented by
+[<i>a</i>]<span class="fs_80"><sub>D</sub></span> = 52°.5
+(<b><a href="#P_107">107</a></b>).</p>
+
+<p><i>Polarization.</i>—The proper weight of milk is placed in a sugar
+flask, diluted with water, clarified with the mercuric salt, the volume
+completed to the mark, and the contents shaken and poured on a filter.
+The filtrate is polarized in tubes of convenient length. The observed
+rotation may be expressed either in degrees of angular measurement or
+of the sugar scale. The weight of milk used may be two or three times
+that of the normal weight calculated for the instrument employed.
+Instead of weighing the milk a corresponding volume determined by its
+specific gravity may be delivered from a burette-pipette (<a href="#Page_231">p. 231</a>).
+For the laurent polariscope three times, and for the half-shadow
+instruments for lamplight, twice the normal weight of milk should be
+used. For approximately sixty cubic centimeters of milk the flask
+should be marked at 105 cubic centimeters in compensation for the
+volume of precipitated solids or the reading obtained from a 100 cubic
+centimeter flask, decreased by one-twentieth.</p>
+
+<p>For the laurent instrument the normal weight of lactose is determined
+by the following proportions:</p>
+
+<p>Gyrodynat of sucrose, 66.5: lactose: 52.5 = <i>x</i>: 16.19.</p>
+
+<p>Whence <i>x</i> = 20.51, that is, the number of grams of pure lactose
+in 100 cubic centimeters required to read 100 divisions of the sugar
+scale of the instrument.</p>
+
+<p>For the ventzke scale the normal quantity of lactose required to read
+100 divisions is found from the following equation:</p>
+
+<div class="blockquot">
+<p class="f105">66.4 : 52.5 = <i>x</i> : 26.048</p>
+
+<p>Whence <span class="fs_105"><i>x</i> = 32.74.</span></p>
+</div>
+
+<p>In the one case three times the normal weight of milk is 61.53 and in
+the other twice the normal weight, 65.48 grams.</p>
+
+<p id="P_244"><b>244. Error due to Volume of Precipitate.</b>—Vieth states that the
+volume allowed for the precipitated solids in the original process,
+<i>viz.</i>, two and four-tenths cubic centimeters, is not sufficiently
+large.<a id="FNanchor_202" href="#Footnote_202" class="fnanchor">[202]</a>
+In such cases it is quite difficult to decide on any arbitrary
+correction based on the supposed quantities of fat and
+<span class="pagenum"><a id="Page_278"></a>[Pg 278]</span>
+albuminoids present. A better method than to try to compensate for
+any arbitrary volume is to remove entirely the disturbing cause or
+eliminate it by indirect means. To wash the precipitate free of sugar
+without increasing the bulk of the filtrate unduly would be extremely
+difficult and tend, moreover, to bring some of the precipitated matters
+again into solution. It is better, therefore, to eliminate the error
+by double dilution and polarization (<b><a href="#P_86">86</a></b>). The principle of this
+method is based on the fact, that, within limits not sensibly affecting
+the gyrodynat by reason of different densities, the polarizations of
+two solutions of the same substance are inversely proportional to their
+volumes.</p>
+
+<p>For convenience, it is recommended that the volumes of the samples in
+each instance be 100 and 200 cubic centimeters, respectively, in which
+case the true reading is obtained by the simple formula given in the
+latter part of <b><a href="#P_86">86</a></b>.</p>
+
+<p>In this laboratory the double dilution method of determining the volume
+of the precipitate is conducted as follows:<a id="FNanchor_203" href="#Footnote_203" class="fnanchor">[203]</a></p>
+
+<p>In each of two flasks marked at 100 and 200 cubic centimeters,
+respectively, are placed 65.52 grams of milk, four cubic centimeters
+of mercuric nitrate added, the volume completed to the mark and the
+contents of the flask well shaken.</p>
+
+<p>After filtering, the polarization is made in a 400 millimeter tube
+by means of the triple shadow polariscope described in <b><a href="#P_75">75</a></b>.
+From the reading thus obtained the volume of the precipitate and the
+degree of correction to be applied are calculated as in the subjoined
+example. The flasks should be filled at near the temperature at which
+the polarizations are made and the observation room must be kept at
+practically a constant temperature of 20° to avoid the complications
+which would be produced by changes in the gyrodynat of lactose and
+the value of the quartz plates and wedges of the apparatus by marked
+variations in temperature.</p>
+
+<p><i>Example.</i>—Weight of milk used in each case 65.52 grams.</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Polarimetric</td>
+      <td class="tdl_wsp">reading</td>
+      <td class="tdl_wsp">from</td>
+      <td class="tdl_wsp">the</td>
+      <td class="tdl_wsp">100</td>
+      <td class="tdl_wsp">cubic</td>
+      <td class="tdl_wsp">centimeter</td>
+      <td class="tdl_wsp">flask,</td>
+      <td class="tdl_wsp">20°.84</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">200</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">10°.15</td>
+   </tr>
+ </tbody>
+</table>
+
+<ul class="index">
+<li class="isub2">Then&emsp;10.15 × 2 = 20.30</li>
+<li class="isub5">20.84 - 20.30 = 0.54</li>
+<li class="isub5">0.54 × 2 = 1.08</li>
+<li class="isub5">20.84 - 1.08 = 19.76</li>
+<li class="isub5">19.76 ÷ 4 = 4.94,</li>
+</ul>
+
+<p class="no-indent"><span class="pagenum"><a id="Page_279"></a>[Pg 279]</span>
+which is the corrected reading showing the percentage of lactose in the
+sample used.</p>
+
+<p>The volume of the precipitate is calculated as follows:</p>
+
+<p>20.84 ÷ 4 = 5.21, the apparent percentage of lactose present.</p>
+
+<p>Then 5.21 : 4.94 = 100 : <i>x</i>.</p>
+
+<p>Whence <i>x</i> = 94.82. From this number it is seen that the true
+volume of the milk solution polarized is 94.82 instead of 100 cubic
+centimeters, whence the volume occupied by the precipitate is 100 -
+94.82 = 5.18 cubic centimeters. So little time is required to conduct
+the analysis by the double dilution method as to render it preferable
+in all cases where incontestable data are desired. Where arbitrary
+corrections are made the volume allowed for the precipitate may vary
+from two and a half cubic centimeters in milks poor in fat, to six for
+those with a high cream content.</p>
+
+<p>For milks of average composition sufficient accuracy is secured by
+making an arbitrary correction of five cubic centimeters for the volume
+of the precipitate.</p>
+
+<h3>SEPARATION OF SUGARS BY CHEMICAL<br> AND CHEMICAL-OPTICAL METHODS.</h3>
+
+<p><b>245. Conditions of Separation.</b>—In the foregoing paragraphs the
+optical methods for determining certain sugars have been described.
+Many cases arise, however, in which these processes are inapplicable or
+insufficient. In these instances, the analyst, as a rule, will be able
+to solve the problem presented by the purely chemical methods which
+have been previously described, or by a combination of the chemical
+and optical processes. Not only have the different sugars distinctive
+relations to polarized light, but also they are oxidized by varying
+quantities of metallic salts and these differences are sufficiently
+pronounced to secure in nearly every instance, no matter how complex,
+data of a high degree of accuracy.</p>
+
+<p>The carbohydrates of chief importance, from an agricultural point of
+view, are starch and sucrose; while the alternation products of chief
+importance, derived therefrom by chemical and biological means, are
+dextrin, maltose, dextrose and invert sugar.
+<span class="pagenum"><a id="Page_280"></a>[Pg 280]</span></p>
+
+<p><b>246. Sucrose, Levulose, and Dextrose.</b>—The purely chemical
+methods of separating these three sugars have been investigated by
+Wiechmann.<a id="FNanchor_204" href="#Footnote_204" class="fnanchor">[204]</a>
+They are based on the data obtained by determining the percentage of
+reducing sugars, both before and after the inversion of the sucrose,
+and before and after the removal of the levulose. For the destruction
+of the levulose, the method of Sieben is employed, and attention is
+called to the fact that the complete removal of the levulose by this
+process is difficult of accomplishment, and is probably attended with
+alterations of the other sugars present.</p>
+
+<p><b>247. Sieben’s Method of Determining Levulose.</b>—The decomposing
+action of hot hydrochloric acid on levulose, and its comparative
+inaction on dextrose are the basis of Sieben’s process.<a id="FNanchor_205" href="#Footnote_205" class="fnanchor">[205]</a>
+The hydrochloric acid employed should contain about 220 grams of the
+pure gas per liter, that is, be of twenty-two per cent strength,
+corresponding to 1.108 specific gravity. If the substance acted on be
+invert sugar, its solution should be approximately of two and a half
+per cent strength. To 100 cubic centimeters of such a solution, sixty
+of the hydrochloric acid are added, and the mixture immersed in boiling
+water for three hours.</p>
+
+<p>After quickly cooling, the acid is neutralized with sodium hydrate of
+thirty-six times normal strength. Ten cubic centimeters of the hydrate
+solution will thus neutralize the sixty of hydrochloric acid which have
+been used to destroy the levulose. The work of Wiechmann discloses the
+fact, easily prevised, that the method used for destroying levulose is
+not always effective and that action of the reagent is not exclusively
+confined to the levogyrate constituent of the mixture. Nevertheless,
+data of reasonable accuracy may be secured by this process, which is
+best carried out as described by Wiechmann. In this connection the
+possibility of the polymerization of the dextrose molecules, when
+heated with hydrochloric acid, must not be overlooked.</p>
+
+<p><b>248. The Analytical Process.</b>—The total quantity of invert sugar
+in a given solution is determined by the methods already given
+(<b><a href="#P_136">136</a>, <a href="#P_141">141</a></b>.)
+<span class="pagenum"><a id="Page_281"></a>[Pg 281]</span></p>
+
+<p>After this has been accomplished, the levulose is destroyed as
+described above, and the dextrose determined by any approved method
+(<b><a href="#P_136">136</a>, <a href="#P_140">140</a></b>). In the presence
+of sucrose, the sum of the reducing sugars is first determined as in
+<b><a href="#P_136">136</a>, <a href="#P_142">142</a></b>. After the inversion
+of the sucrose, the invert sugar is again determined, and the increased
+quantity found, calculated to sucrose. The levulose is then destroyed
+by hydrochloric acid, and the dextrose determined as described above.
+The quantity of sucrose may also be determined by an optical method
+(<b><a href="#P_91">91</a>, <a href="#P_92">92</a>, <a href="#P_94">94</a></b>.).</p>
+
+<p><b>249. Calculation of Results.</b>—If we represent by a the weight
+of metallic copper reduced by the invert sugar present in a solution
+containing sucrose, and by <i>b</i> that obtained after the inversion
+of the sucrose, the quantity of copper corresponding to the sucrose is
+<i>b - a</i> = <i>c</i>. After the destruction of the levulose, the
+copper reduced by the residual dextrose may be represented by <i>d</i>.
+The weight of copper equivalent to the levulose is, therefore, <i>b
+- d</i> = <i>e</i>. From the tables already given, the corresponding
+quantities of the sugars equivalent to <i>c, d</i>, and <i>e</i> are
+directly taken. Example:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl" rowspan="3"><i>a</i> =</td>
+      <td class="tdl_wsp" rowspan="3">300</td>
+      <td class="tdl_wsp" rowspan="3">milligrams</td>
+      <td class="tdc" rowspan="3">&nbsp;=&nbsp;</td>
+      <td class="tdc" rowspan="3"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdl_wsp">163.8</td>
+      <td class="tdl_wsp">milligrams</td>
+      <td class="tdl_wsp">invert sugar.</td>
+   </tr><tr>
+      <td class="tdl_wsp">156.5</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">dextrose.</td>
+   </tr><tr>
+      <td class="tdl_wsp">185.63</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">levulose.</td>
+   </tr><tr>
+      <td class="tdl"><i>b</i> =</td>
+      <td class="tdl_wsp">500</td>
+      <td class="tdc">”</td>
+      <td class="tdc" colspan="5">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl"><i>d</i> =</td>
+      <td class="tdl_wsp">275</td>
+      <td class="tdc">”</td>
+      <td class="tdc">=</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdl_wsp">142.8</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">dextrose.</td>
+   </tr><tr>
+      <td class="tdl"><i>c</i> =</td>
+      <td class="tdl_wsp">200</td>
+      <td class="tdc">”</td>
+      <td class="tdc">=</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdl_wsp">106.3</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">invert sugar.</td>
+   </tr><tr>
+      <td class="tdl"><i>e</i> =</td>
+      <td class="tdl_wsp">225</td>
+      <td class="tdc">”</td>
+      <td class="tdc">=</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdl_wsp">133.89</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">levulose.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The 106.3 milligrams of invert sugar equivalent to <i>c</i>, correspond
+to 101 milligrams of sucrose. The quantity of dextrose equivalent to
+275 milligrams of copper is 142.8. Of this amount 53.15 milligrams are
+due to the inverted sucrose, leaving 89.65 milligrams arising from
+the invert sugar and dextrose originally present. This quantity is
+equivalent to 175 milligrams of copper.</p>
+
+<p>Of the 300 milligrams of copper obtained in the first instance, 125
+are due to levulose in the original sample, corresponding to 69.73
+milligrams which number, multiplied by two, gives the invert sugar
+present.</p>
+<p><span class="pagenum"><a id="Page_282"></a>[Pg 282]</span></p>
+<p>The sample examined, therefore, had the following composition:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Sucrose</td>
+      <td class="tdr">101.00</td>
+      <td class="tdl_wsp">milligrams.</td>
+   </tr><tr>
+      <td class="tdl">Invert sugar&emsp;&nbsp;</td>
+      <td class="tdr">139.46</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl">Dextrose</td>
+      <td class="tdr bb">19.92</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl_ws1">Sum</td>
+      <td class="tdr">260.38</td>
+      <td class="tdc">”</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>On the other hand, if the invert sugar be calculated from the quantity
+corresponding to the 225 milligrams of copper corresponding to
+<i>e</i>, the data will be very different from those given above. In
+this instance of the levulose found corresponding to 225 milligrams
+of copper, <i>viz.</i>, 133.89, 53.15 milligrams are due to the
+inverted sucrose. Then the quantity due to the invert sugar at first
+present is 133.89 - 53.15 = 80.74 milligrams. Since half the weight
+of invert sugar is levulose, the total weight of the invert sugar at
+first present is 161.48, leaving only 8.91 milligrams due to added
+dextrose. The difficulties in these calculations doubtless arise from
+the imperfect destruction of the levulose, and from variations in the
+reducing action of sugars on copper salts in the presence of such large
+quantities of sodium chlorid.</p>
+
+<p><b>250. Calculation from Data obtained with Copper Carbonate.</b>—The
+wide variations observed in different methods of calculations in the
+preceding paragraph, are due in part to the different degrees of
+oxidation exerted on alkaline copper tartrate by the dextrose and
+levulose. Better results are obtained by conducting the analytical work
+with Ost’s modification of Soldaini’s solution (<b><a href="#P_128">128</a></b>).</p>
+
+<p>The relative quantities of levulose and dextrose oxidized by this
+solution are almost identical, and the calculations, therefore, result
+in nearly the same data, whether made from the numbers obtained with
+the residual dextrose or from the levulose destroyed. The method of
+applying this method is illustrated in the following calculation.</p>
+
+<p><i>Example.</i>—In a mixture of sucrose, invert sugar, and dextrose,
+the quantities of copper obtained by using the copper carbonate
+solution were as follows:
+<span class="pagenum"><a id="Page_283"></a>[Pg 283]</span></p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Copper</td>
+      <td class="tdl_wsp">obtained</td>
+      <td class="tdl_wsp">before</td>
+      <td class="tdl_wsp">inversion</td>
+      <td class="tdl_wsp">= <i>a</i> =</td>
+      <td class="tdl_wsp">150</td>
+      <td class="tdl_wsp">milligrams.</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">after</td>
+      <td class="tdl_ws2">”</td>
+      <td class="tdl_wsp">= <i>b</i> =</td>
+      <td class="tdl_wsp">250</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">destroying lev’e</td>
+      <td class="tdl_wsp">= <i>d</i> =</td>
+      <td class="tdl_wsp">137.5</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">equivalent</td>
+      <td class="tdc">to</td>
+      <td class="tdl_wsp">inverted sucrose</td>
+      <td class="tdl_wsp">= <i>b</i> - <i>a</i> = <i>c</i> =</td>
+      <td class="tdl_wsp">100</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">levulose</td>
+      <td class="tdl_wsp">= <i>b</i> - <i>d</i> = <i>e</i> =</td>
+      <td class="tdl_wsp">112.5</td>
+      <td class="tdc">”</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl" rowspan="3"><i>a</i> =</td>
+      <td class="tdl_wsp" rowspan="3">150</td>
+      <td class="tdl_wsp" rowspan="3">milligrams</td>
+      <td class="tdl_wsp" rowspan="3">Cu</td>
+      <td class="tdl_wsp" rowspan="3">=&nbsp;</td>
+      <td class="tdc" rowspan="3"><img src="images/cbl-3.jpg" alt="" width="16" height="57" ></td>
+      <td class="tdl_wsp">44.0</td>
+      <td class="tdl_wsp">milligrams</td>
+      <td class="tdl_wsp">invert sugar</td>
+   </tr><tr>
+      <td class="tdl_wsp">45.3</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">dextrose</td>
+   </tr><tr>
+      <td class="tdl_wsp">42.5</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">levulose.</td>
+   </tr><tr>
+      <td class="tdl"><i>d</i> =</td>
+      <td class="tdl_wsp">137.5</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">=&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdl_wsp">41.55</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">dextrose.</td>
+   </tr><tr>
+      <td class="tdl"><i>c</i> =</td>
+      <td class="tdl_wsp">100</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">=&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdl_wsp">29.5</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">invert sugar</td>
+   </tr><tr>
+      <td class="tdl" colspan="7">&nbsp;</td>
+      <td class="tdr_wsp">= 28.025</td>
+      <td class="tdl_wsp">sucrose.</td>
+   </tr><tr>
+      <td class="tdl"><i>e</i> =</td>
+      <td class="tdl_wsp">112.5</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">=&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdl_wsp">31.9</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">levulose.</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">14.75</td>
+      <td class="tdl_wsp">milligrams</td>
+      <td class="tdl_wsp">of</td>
+      <td class="tdl_wsp">dextrose =</td>
+      <td class="tdl_wsp">48.5</td>
+      <td class="tdl_wsp">milligrams</td>
+      <td class="tdl_wsp">Cu.</td>
+   </tr><tr>
+      <td class="tdl">14.75</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">levulose =</td>
+      <td class="tdl_wsp">51.5</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>137.5 - 48.5 = 89.0 milligrams Cu due to dextrose present before inversion.</p>
+
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl" rowspan="3">150.0 -</td>
+      <td class="tdl_wsp">89.0</td>
+      <td class="tdl_wsp">milligrams</td>
+      <td class="tdl_wsp">Cu</td>
+      <td class="tdl_wsp">= 27</td>
+      <td class="tdl_wsp">milligrams</td>
+      <td class="tdl_wsp">dextrose before inversion.</td>
+   </tr><tr>
+      <td class="tdl_wsp">89.0</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">= 61.0</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">Cu due to levulose present before inversion.</td>
+   </tr><tr>
+      <td class="tdl_wsp">61.0</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">= 17.8</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">levulose before inversion.</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdr">17.8 × 2 =</td>
+      <td class="tdl_wsp">35.6</td>
+      <td class="tdl_wsp">milligrams</td>
+      <td class="tdl_wsp">invert sugar</td>
+      <td class="tdl_wsp">present</td>
+      <td class="tdl_wsp">before</td>
+      <td class="tdl_wsp">inversion.</td>
+   </tr><tr>
+      <td class="tdl">27.0 - 17.8 =</td>
+      <td class="tdl_wsp">&#8199;9.2</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">dextrose</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="no-indent fs_105">Again:</p>
+
+<ul class="index">
+<li class="isub2">112.5 - 51.5 = 61.0 milligrams Cu due to levulose present before inversion.</li>
+<li class="isub2">61.0 milligrams Cu = 17.8 milligrams levulose.</li>
+<li class="isub2">17.8      ”   levulose indicate 35.6 milligrams invert sugar.</li>
+<li class="isub2">Dextrose in invert sugar before inversion = 17.8 milligrams.</li>
+<li class="isub2">Total dextrose before inversion = 27.0 milligrams.</li>
+<li class="isub2">Dextrose above amount required for invert sugar = 27.0 - 17.8= 9.2 milligrams.</li>
+</ul>
+
+<p>The respective quantities of the three sugars in the solution are,
+therefore:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Sucrose</td>
+      <td class="tdl_wsp">= 28.025</td>
+      <td class="tdl_wsp">milligrams.</td>
+   </tr><tr>
+      <td class="tdl">Invert sugar &nbsp;</td>
+      <td class="tdl_wsp">= 35.6</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl">Dextrose</td>
+      <td class="tdl_wsp">= 9.2</td>
+      <td class="tdc">”</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The calculations made from the later data (<b><a href="#P_234">234</a></b>)
+give almost the same results.</p>
+
+<p><b>251. Winter’s Process.</b>—Winter has proposed a method of
+separating dextrose and levulose in the presence of sucrose based on
+<span class="pagenum"><a id="Page_284"></a>[Pg 284]</span>
+the selective precipitation produced on treating mixtures of these
+sugars in solution with ammoniacal lead acetate.<a id="FNanchor_206" href="#Footnote_206" class="fnanchor">[206]</a></p>
+
+<p>The reagent is prepared immediately before use by adding ammonia to
+a solution of lead acetate until the opalescence which is at first
+produced just disappears. The separation is based on the fact that
+the compound of sucrose with the reagent is easily soluble in water,
+while the salts formed with levulose and dextrose are insoluble. The
+separation of the sugars is accomplished as follows:</p>
+
+<p>The ammoniacal lead acetate is added to the solution of the mixed
+sugars until no further precipitate is produced. The precipitated
+matters are digested with a large excess of water and finally separated
+by filtration. The sucrose is found in the filtrate in the form of a
+soluble lead compound, from which it is liberated by treatment with
+carbon dioxid. The lead carbonate produced is separated by filtration
+and the sucrose is estimated in an aliquot part of the filtrate by
+optical or chemical methods. The precipitate containing the lead
+compounds of dextrose and levulose is washed free of sucrose, suspended
+in water and saturated with carbon dioxid. By this treatment the lead
+compound with dextrose is decomposed and, on filtration, the dextrose
+will be found in the filtrate, while the lead compound of the levulose
+is retained upon the filter with the lead carbonate. After well washing
+the precipitate, it is again suspended in water and saturated with
+hydrogen sulfid. By this treatment the lead levulosate compound is
+broken up and the levulose obtained, on subsequent filtration, in
+the filtrate. The dextrose and levulose, after separation as above
+described, may be determined in aliquot parts of their respective
+filtrates by the usual gravimetric methods. Before determining the
+levulose the solution should be heated until all excess of hydrogen
+sulfid is expelled.</p>
+
+<p>This method was used especially by Winter in separating the various
+sugars obtained in the juices of sugar cane. It has not been largely
+adopted as a laboratory method, and on account of the time and trouble
+required for its conduct, is not likely to assume any very great
+practical importance.</p>
+
+<p><b>252. Separation of Sugars by Lead Oxid.</b>—In addition to the
+combination with the earthy bases, sugar forms well defined compounds
+<span class="pagenum"><a id="Page_285"></a>[Pg 285]</span>
+with lead oxid. One of these compounds is of such a nature as to have
+considerable analytical and technical value. Its composition and the
+method of preparing it have been pointed out by Kassner.<a id="FNanchor_207" href="#Footnote_207" class="fnanchor">[207]</a></p>
+
+<p>Sucrose, under conditions to be described, forms with the lead oxid
+a diplumbic saccharate, which separates in spheroidal crystals, and
+has the composition corresponding to the formula <b>C₁₂H₁₈O₁₁Pb₂ + 5H₂O</b>.
+The precipitation takes place quantitively and should be conducted as
+follows:</p>
+
+<p>The substance containing the sucrose, which may be molasses, sirups
+or concentrated juices, is diluted with enough water to make a sirup
+which is not too viscous. Lead oxid suspended in water is stirred into
+the mass in such proportion as to give about two parts of oxid to one
+of the sugar. The stirring is continued for some time until the oxid
+is thoroughly distributed throughout the mass and until it becomes
+thick by the commencement of the formation of the saccharate. As soon
+as the mass is sufficiently thickened to prevent the remaining lead
+oxid from settling, the stirring may be discontinued and the mixture
+is left for twenty-four hours, at the end of which time the sucrose
+has all crystallized in the form of lead saccharate. The crystals of
+lead saccharate can be separated by a centrifugal machine or by passing
+through a filter press, and are thoroughly washed with cold water, in
+which they are almost insoluble. The washed crystals are beaten up with
+water into a thick paste and the lead separated as basic carbonate by
+carbon dioxid. The sucrose is found in solution in the residual liquor
+and is concentrated and crystallized in the usual way.</p>
+
+<p>Reducing sugars have a stronger affinity for the lead oxid than the
+sucrose, and this fact is made use of to effect a nearly complete
+separation when they are mixed together. In order to secure this the
+lead oxid is added in the first place only in sufficient quantity to
+combine with the reducing sugars present, the process being essentially
+that described above. The reducing sugars which are precipitated as
+lead dextrosates, lead levulosates, etc., are separated in the usual
+way by a centrifugal or a filter press, and the resulting liquor,
+which contains still nearly all the sucrose, is subjected to a second
+<span class="pagenum"><a id="Page_286"></a>[Pg 286]</span>
+precipitation by the addition of lead oxid. The second precipitation
+obtained is almost pure diplumbic saccharate.</p>
+
+<p>In the precipitation of the sugar which is contained in the beet
+molasses, where only a trace or very little invert sugar is present,
+the sucrose is almost quantitively separated, and by the concentration
+of the residual liquor, potash salts are easily obtained. In this case,
+after the decomposition of the lead saccharate by carbon dioxid, the
+residual sugar solution is found entirely free of lead. Where invert
+sugar is present, however, in any considerable proportions, it is found
+to exercise a slightly soluble influence on the lead saccharate, and
+in this case a trace of lead may pass into solution. For technical
+purposes, this is afterwards separated by hydrosulfuric acid or the
+introduction of lime sulfid.</p>
+
+<p>Lead oxid is regenerated from the basic lead carbonate obtained by
+heating in retorts to a little above 260°, and the carbon dioxid
+evolved can also be used again in the technical process.</p>
+
+<p><b>253. Commercial Glucose and Grape Sugar.</b>—The commercial
+products obtained by the hydrolysis of starch are known in the trade
+as glucose or grape sugar. The former term is applied to the thick
+sirup obtained by concentrating the products of a partial hydrolysis,
+while the latter is applied to the solid semi-crystalline mass, secured
+by continuing the hydrolyzing action until the intermediate products
+are almost completely changed to dextrose. In this country the starch
+employed is obtained almost exclusively from maize, and the hydrolyzing
+agent used is sulfuric acid.<a id="FNanchor_208" href="#Footnote_208" class="fnanchor">[208]</a>
+The products of conversion in glucose are chiefly dextrins and dextrose
+with some maltose, and in grape sugar almost entirely dextrose.
+When diastase is substituted for an acid, as the hydrolytic agent,
+maltose is the chief product, the ferment having no power of producing
+dextrose. In the glucose of Japan, known as midzu ame dextrin and
+maltose are the chief constituents.<a id="FNanchor_209" href="#Footnote_209" class="fnanchor">[209]</a></p>
+
+<p>Commercial glucose is used chiefly by confectioners for manufacturing
+table sirups and for adulterating honey and molasses.</p>
+
+<p>Commercial grape sugar is chiefly employed by brewers as a substitute
+for barley and other grains.
+<span class="pagenum"><a id="Page_287"></a>[Pg 287]</span></p>
+
+<p>In Europe, the starch which is converted into glucose, is derived
+principally from potatoes. The method employed in conversion, whether
+an acid or diastatic action, is revealed not only by the nature of
+the product, but also by the composition of its ash. In the case of
+diastatic conversion the ash of the sample will contain only a trace of
+sulfates, no chlorin, and be strongly alkaline, while the product of
+conversion with sulfuric acid will give an ash rich in sulfates with a
+little lime and be less strongly alkaline.</p>
+
+<p>The process of manufacture in this country consists in treating the
+starch, beaten to a cream with water, with sulfuric acid, usually under
+pressure, until the product shows no blue color with iodin. The excess
+of acid is removed with marble dust, the sirup separated by filtration,
+whitened by bleaching with sulfurous acid or by passing it through
+bone-black and evaporated to the proper consistence in a vacuum. The
+solid sugar, consisting mostly of dextrose, is made in the same manner,
+save that the heating with the acid is continued until the dextrin and
+maltose are changed into maltose. The product is either obtained in
+its ordinary hydrated form or by a special method of crystallization
+secured as bright anhydrous crystals. Solutions of dextrose, when first
+made, show birotation, but attain their normal gyrodynatic state on
+standing for twenty-four hours in the cold, or immediately on boiling.</p>
+
+<p><b>254. Methods Of Separation.</b>—The accurate determination of the
+quantities of the several optically active bodies formed in commercial
+glucose is not possible by any of the methods now known. Approximately
+accurate data may be secured by a large number of processes, and these
+are based chiefly on the ascertainment of the rotation and reducing
+power of the mixed sugars, the subsequent removal of the dextrose and
+maltose by fermentation or oxidation and the final polarization of the
+residue. The difficulties which attend these processes are alike in
+all cases. Fermentation may not entirely remove the reducing sugars or
+may act slightly on the dextrin. In like manner the oxidation of these
+sugars by metallic salts may not entirely decompose them, may leave an
+optically active residue, or may affect the optical activity of the
+<span class="pagenum"><a id="Page_288"></a>[Pg 288]</span>
+residual dextrin. The quantitive methods of separating these sugars
+by means of phenylhydrazin, lead salts or earthy bases have not been
+developed into reliable and applicable laboratory processes. At the
+present time the analyst must be contented with processes confessedly
+imperfect, but which, with proper precautions, yield data which are
+nearly correct. The leading methods depending on fermentation and
+oxidation combined with polarimetric observations will be described in
+the subjoined paragraphs.</p>
+
+<p><b>255. Fermentation Method.</b>—This process is based on the
+assumption that, under certain conditions, dextrose and maltose may
+be removed from a solution and the dextrin be left unchanged. In
+practice, approximately accurate results are obtained by this method,
+although the assumed conditions are not strictly realized. In the
+prosecution of this method the polarimetric reading of the mixed sugars
+is made, and the maltose and dextrose removed therefrom by fermentation
+with compressed yeast. The residual dextrins are determined by the
+polariscope on the assumption that their average gyrodynat is 193.
+In the calculation of the quantities of dextrose and maltose their
+gyrodynats are fixed at 53 and 138 respectively. The total quantity
+of reducing sugar is determined by the usual processes. The relative
+reducing powers of dextrose and maltose are represented by 100 and 62
+respectively. The calculations are made by the following formulas:<a id="FNanchor_210" href="#Footnote_210" class="fnanchor">[210]</a></p>
+
+<ul class="index">
+<li class="isub2"><i>R</i>  = reducing sugars as dextrose</li>
+<li class="isub2"><i>d</i>  = dextrose</li>
+<li class="isub2"><i>m</i>  = maltose</li>
+<li class="isub2"><i>dʹ</i> = dextrin</li>
+<li class="isub2"><i>P</i>  = total polarization (calculated as apparent gyrodynat)</li>
+<li class="isub2"><i>Pʹ</i> = rotation after fermentation (calculated as apparent gyrodynat).</li>
+</ul>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl_top" rowspan="3">Whence &nbsp;</td>
+      <td class="tdl"><i>R</i></td>
+      <td class="tdl_wsp">= <i>d</i> + 0.62<i>m</i></td>
+      <td class="tdr">(1)</td>
+   </tr><tr>
+      <td class="tdl"><i>P</i></td>
+      <td class="tdl_wsp">= 53<i>d</i> + 138<i>m</i> + 163<i>dʹ</i><span class="ws2">&nbsp;</span></td>
+      <td class="tdr">(2)</td>
+   </tr><tr>
+      <td class="tdl"><i>Pʹ</i></td>
+      <td class="tdl_wsp">= 193<i>dʹ</i></td>
+      <td class="tdr">(3)</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>From these three equations the values of <i>d</i>, <i>m</i>, and
+<i>dʹ</i> are readily calculated:
+<span class="pagenum"><a id="Page_289"></a>[Pg 289]</span></p>
+
+<p class="fs_105 spa1"><i>Example</i>: To find <i>d</i> and <i>m</i>:</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdr_top" rowspan="3">Subtract (3) from (2) &nbsp;</td>
+      <td class="tdr"><i>P</i>  =</td>
+      <td class="tdl_wsp">53<i>d</i> + 133<i>m</i> + 193<i>dʹ</i></td>
+      <td class="tdr">&nbsp;</td>
+   </tr><tr>
+      <td class="tdr bb"><i>Pʹ</i> =</td>
+      <td class="tdl_wsp bb"><span class="ws6">193<i>dʹ</i></span></td>
+      <td class="tdr">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl"><i>P</i> - <i>Pʹ</i> =</td>
+      <td class="tdl_wsp">53<i>d</i> + 138<i>m</i></td>
+      <td class="tdr">&nbsp;&emsp;(4)</td>
+   </tr><tr>
+      <td class="tdl" colspan="4">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl_top" rowspan="3">Multiply (1) by 53 and subtract from (4) &nbsp;</td>
+      <td class="tdr"><i>P</i> - <i>Pʹ</i> =</td>
+      <td class="tdl_wsp">53<i>d</i> + 138<i>m</i></td>
+      <td class="tdr">&nbsp;</td>
+   </tr><tr>
+      <td class="tdr bb">53<i>R</i>  =</td>
+      <td class="tdl_wsp bb">53<i>d</i> +  32.86<i>m</i></td>
+      <td class="tdr">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl"><i>P</i> - <i>Pʹ</i> -</td>
+      <td class="tdl_wsp">53<i>R</i> = 105.14<i>m</i></td>
+      <td class="tdr">&nbsp;&emsp;(5)</td>
+   </tr><tr>
+      <td class="tdl" colspan="4">&nbsp;</td>
+   </tr><tr>
+      <td class="tdr_top" rowspan="2">Whence <i>m</i> = &nbsp;</td>
+      <td class="tdl bb"><i>P</i> - <i>Pʹ</i> - 53<i>R</i></td>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdl" rowspan="2"><span class="ws2">(6)</span></td>
+   </tr><tr>
+      <td class="tdc">105.14</td>
+      <td class="tdl">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="f105"><i>d</i> = <i>R</i> - 0.62<i>m</i><span class="ws5">(7)</span></p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>dʹ</i> = &nbsp;</td>
+      <td class="tdc bb"><i>Pʹ</i></td>
+      <td class="tdl" rowspan="2"><span class="ws7">(8)</span></td>
+   </tr><tr>
+      <td class="tdc">193</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Sidersky assigns the values [<i>a</i>]<span class="fs_80"><sub>D</sub></span>
+= 138.3 and [<i>a</i>]<span class="fs_80"><sub>D</sub></span> = 194.8 to maltose
+and dextrin respectively in the above formulas.<a id="FNanchor_211" href="#Footnote_211" class="fnanchor">[211]</a></p>
+
+<p><i>Illustration</i>: In the examination of a sample 26.048 grams of
+midzu ame in 100 cubic centimeters were polarized in a 200 millimeter
+tube and the following data were obtained:</p>
+
+<p>Polarization of sample in angular degrees 69°.06, which is equal to an
+apparent gyrodynat of 132.6:</p>
+
+<p>Total reducing sugar as dextrose 33.33 per cent:</p>
+
+<p>Polarization in angular degrees after fermentation 30°.84 =
+[<i>a</i>]<span class="fs_80"><sub>D</sub></span> = 59.2.</p>
+
+<p>Substituting these values in the several equations gives the following
+numbers:</p>
+
+<ul class="index">
+<li class="isub2">(1)&nbsp;&emsp;&nbsp;0.3333 = <i>d</i> + 0.62<i>m</i></li>
+<li class="isub2">(2)&nbsp;&emsp;132.6 = 53<i>d</i> + 138<i>m</i> + 193<i>dʹ</i></li>
+<li class="isub2">(3)&nbsp;&emsp;&nbsp;59.2 = 193<i>dʹ</i></li>
+<li class="isub2">(4)&nbsp;&emsp;&nbsp;73.4 = 53<i>d</i> + 138<i>m</i></li>
+<li class="isub2">(5)&nbsp;&emsp;&nbsp;55.74 = 105.14<i>m</i></li>
+<li class="isub2">(6) <i>m</i> = 0.5301 = 53.01 per cent.</li>
+<li class="isub2">(7) <i>d</i> = 3333 - 3286 = 0.0047 =  00.47 per cent.</li>
+<li class="isub2">(8) <i>dʹ</i> = 59.2 ÷ 193 = 0.3067 = 30.67  ”   ”</li>
+</ul>
+
+<p><span class="pagenum"><a id="Page_290"></a>[Pg 290]</span>
+<i>Summary</i>: Sample of midzu ame:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Percentage</td>
+      <td class="tdl_wsp">of</td>
+      <td class="tdl_wsp">dextrin</td>
+      <td class="tdr">30.67</td>
+      <td class="tdl_wsp">per</td>
+      <td class="tdl_wsp">cent.</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">maltose</td>
+      <td class="tdr">53.01</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">dextrose</td>
+      <td class="tdr">00.47</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">water</td>
+      <td class="tdr">14.61</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">ash</td>
+      <td class="tdr bb">00.31</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdl_wsp">Sum</td>
+      <td class="tdr">99.07</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdl_wsp">Undetermined&emsp;&nbsp;</td>
+      <td class="tdr">0.93</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>For polarization the lamplight shadow polariscope employed for sugar
+may be used, and the degrees of the sugar (ventzke) scale converted
+into angular degrees by multiplying by 0.3467.</p>
+
+<p>The process of fermentation is conducted as described in the paragraph
+given further on, relating to the determination of lactose in the
+presence of sucrose.</p>
+
+<p><b>256. The Oxidation Method.</b>—The removal of the reducing sugars
+may be accomplished by oxidation instead of fermentation. The process
+of analysis is in all respects similar to that described in the
+foregoing paragraph, substituting oxidation for fermentation.<a id="FNanchor_212" href="#Footnote_212" class="fnanchor">[212]</a>
+For the oxidizing agent mercuric cyanid is preferred, and it is
+conveniently prepared by dissolving 120 grams of mercuric cyanid and
+an equal quantity of sodium hydroxid in water mixing the solutions
+and completing the volume to one liter. If a precipitate be formed
+in mixing the solutions it should be removed by filtering through
+asbestos. For the polarization, ten grams of the sugars in 100 cubic
+centimeters is a convenient quantity. Ten cubic centimeters of
+this solution are placed in a flask of water marked at fifty cubic
+centimeters, a sufficient quantity of the mercuric cyanid added to
+remain in slight excess after the oxidation is finished (from twenty to
+twenty-five cubic centimeters) and the mixture heated to the boiling
+point for three minutes. The alkali, after cooling, is neutralized with
+strong hydrochloric acid and the passing from alkalinity to acidity
+will be indicated by a discharge of the brown color which is produced
+by heating with the alkaline mercuric cyanid. The heating with the
+mercury salt should be conducted in a well ventilated fume chamber.
+<span class="pagenum"><a id="Page_291"></a>[Pg 291]</span></p>
+
+<p>The calculation of the results is conducted by means of the formulas
+given in the preceding paragraph. In the original paper describing
+this method, it was stated that its accuracy depended on the complete
+oxidation of the reducing sugar in a manner leaving no optically active
+products, and on the inactivity of the reagents used in respect to the
+dextrin present. These two conditions are not rigidly fulfilled, as is
+shown by Wilson.<a id="FNanchor_213" href="#Footnote_213" class="fnanchor">[213]</a>
+According to his data maltose leaves an optically active residue, which
+gives a somewhat greater right hand rotation than is compensated for
+by the diminished rotation of the dextrin. Wilson, however, confesses
+that the dextrin used contained reducing sugars, which would not be the
+case had it been prepared by the process of treating it with alkaline
+mercuric cyanid as above indicated. Upon the whole, the oxidation
+of the reducing sugar by a mercury salt gives results which, while
+not strictly accurate, are probably as reliable as those afforded by
+fermentation. The author has attempted to supplant both the oxidation
+and fermentation methods by removing the reducing sugars with a
+precipitating reagent, such as phenylhydrazin, but the methods are not
+sufficiently developed for publication.</p>
+
+<p><b>257. Removal of Dextrose by Copper Acetate.</b>—Maercker first
+called attention to the fact that Barfoed’s reagent (one part copper
+acetate in fifteen parts of water, and 200 cubic centimeters of this
+solution mixed with five cubic centimeters of thirty-eight per cent.
+acetic acid) reacts readily with dextrose, while it is indifferent to
+maltose and dextrins. Sieben’s method of removing dextrose is based on
+this fact.<a id="FNanchor_214" href="#Footnote_214" class="fnanchor">[214]</a>
+It is found that under certain conditions pure maltose
+does not reduce either the acidified or neutral solution of copper
+acetate, while dextrose or a mixture of dextrose and maltose does so
+readily. It is also shown that the fermentation residue under suitable
+conditions acts like maltose. Maltose solutions reduce the reagent
+after boiling four minutes while at 40°-45° they have no effect even
+after standing four days. The amount of copper deposited by dextrose,
+under the latter conditions, is found to depend to a certain extent on
+the amount of free acetic acid present, and as the solutions of copper
+acetate always contain varying quantities of acetic acid which cannot
+be removed without decomposition and precipitation of basic salt, the
+<span class="pagenum"><a id="Page_292"></a>[Pg 292]</span>
+use of an absolutely neutral solution is impracticable. The reagent
+prepared according to Barfoed’s directions is almost saturated, but a
+half normal solution is preferable. Sieben proposes two solutions: I,
+containing 15.86 grams copper and 0.56 gram acetic anhydrid per liter;
+II, containing 15.86 grams copper and three grams acetic anhydrid per
+liter. The reduction of the dextrose is secured by placing 100 cubic
+centimeters of the solution in a bottle, adding the sugar solution,
+stoppering and keeping in a water-bath at 40°-45° two or three days. An
+aliquot portion is then drawn off and the residual copper precipitated
+by boiling with forty-five cubic centimeters of the alkali solution
+of the fehling reagent and forty cubic centimeters of one per cent
+dextrose solution, filtered and weighed as usual. The results show that
+either solution can be used, and that standing for two days at 45°
+is sufficient. One hundred cubic centimeters of the copper solution
+are mixed with ten cubic centimeters of the sugar solution containing
+from two-tenths to five-tenths gram of dextrose, as this dilution
+gives the best results. No reduction is found to have taken place when
+solutions containing five-tenths gram maltose or five-tenths gram
+fermentation residue are used. The data can not be compiled in the
+form of a table similar to Allihn’s, as it is impossible to obtain a
+solution of uniform acidity each time, and the solution will have to be
+standardized by means of a known pure dextrose solution and the result
+obtained with the unknown sugar solution properly diluted compared with
+this. This method of Sieben’s has never been practiced to any extent in
+analytical separations and can not, therefore, be strongly recommended
+without additional experience.</p>
+
+<p><b>258. Removal of Dextrin by Alcohol.</b>—By reason of its less
+solubility, dextrin can be removed from a solution containing
+also dextrose and maltose by precipitation with alcohol. It is
+impracticable, however, to secure always that degree of alcoholic
+concentration which will cause the coagulation of all the dextrins
+without attacking the concomitant reducing sugars. In this laboratory
+it has been found impossible to prepare a dextrin by alcoholic
+precipitation, which did not contain bodies capable of oxidizing
+alkaline copper solutions.
+<span class="pagenum"><a id="Page_293"></a>[Pg 293]</span></p>
+
+<p>The solution containing the dextrin is brought to a sirupy consistence
+by evaporation and treated with about ten volumes of ninety per cent
+alcohol. After thorough mixing, the precipitated dextrin is collected
+on a filter and well washed with alcohol of the strength noted. It is
+then dried and weighed. If weaker solutions of dextrin are used, the
+alcohol must be of correspondingly greater strength. In the filtrate
+the residual maltose and dextrose may be separated and determined by
+the chemical and optical methods already described.</p>
+
+<h3>CARBOHYDRATES IN MILK.</h3>
+
+<p id="P_259"><b>259. The Copper Tartrate Method.</b>—The lactose in milk is readily
+estimated by the gravimetric copper method described in paragraph
+<b>1<a href="#P_143">43</a></b>. Before the application of the process the casein and fat
+of the milk should be removed by an appropriate precipitant, and an
+aliquot part of the filtrate, diluted to contain about one per cent
+of milk sugar, used for the determination. The clarification is very
+conveniently secured by copper sulfate or acetic acid, as described
+in the next paragraph. A proper correction should be made for the
+volume occupied by the precipitate and, for general purposes, with
+whole milk of fair quality this volume may be assumed to be five per
+cent. One hundred grams of milk will give a precipitate occupying
+approximately five cubic centimeters. In the analytical process, to
+twenty cubic centimeters of milk, diluted with water to eighty, is
+added a ten per cent solution of acetic acid, until a clear whey is
+shown after standing a few minutes, when the volume is completed to 100
+cubic centimeters with water, and the whole, after thorough shaking,
+thrown on a filter. An aliquot part of the filtrate is neutralized with
+sodium carbonate and used for the lactose determination. This solution
+contains approximately one per cent of lactose. In a convenient part
+of it the lactose is determined and the quantity calculated for the
+whole. This quantity represents the total lactose in the twenty
+cubic centimeters of milk used. The weight of the milk is found by
+multiplying twenty by its specific gravity. From this number the
+percentage of lactose is easily found. In this process the milk is
+clarified by the removal of its casein and fat. Other albuminoids
+<span class="pagenum"><a id="Page_294"></a>[Pg 294]</span>
+remain in solution and while these doubtless disturb the subsequent
+determination of lactose, any attempt at their removal would be equally
+as disadvantageous. The volume of the precipitate formed by good, whole
+milk when the process is conducted as above described, is about one
+cubic centimeter, for which a corresponding correction is readily made.</p>
+
+<p><b>260. The Official Method.</b>—The alkaline copper method
+of determining lactose, adopted by the Association of Official
+Agricultural Chemists, is essentially the procedure proposed by
+Soxhlet.<a id="FNanchor_215" href="#Footnote_215" class="fnanchor">[215]</a></p>
+
+<p>Dilute twenty-five cubic centimeters of the milk, held in a half
+liter flask, with 400 cubic centimeters of water and add ten cubic
+centimeters of a solution of copper sulfate of the strength given for
+Soxhlet’s modification of Fehling’s solution, <a href="#Page_129">page 129</a>;
+add about seven and a half cubic centimeters of a solution of potassium
+hydroxid of such strength that one volume of it is just sufficient
+to completely precipitate the copper as hydroxid from one volume of
+the solution of copper sulfate. In place of a solution of potassium
+hydroxid of this strength eight and a half cubic centimeters of a half
+normal solution of sodium hydroxid may be used. After the addition
+of the alkali solution the mixture must still have an acid reaction
+and contain copper in solution. Fill the flask to the mark, shake and
+filter through a dry filter.</p>
+
+<p>Place fifty cubic centimeters of the mixed copper reagent in a beaker
+and heat to the boiling point. While boiling briskly, add 100 cubic
+centimeters of the lactose solution, prepared as directed above, and
+boil for six minutes. Filter immediately and determine the amount of
+copper reduced by one of the methods already given, <a href="#Page_149">pages 149-155</a>.
+Obtain the weight of lactose equivalent to the weight of copper found
+from the table on <a href="#MILK_SUGAR">page 163</a>.</p>
+
+<p><b>261. The Copper Cyanid Process.</b>—It has been found by Blyth that
+the copper cyanid process of Gerrard gives practically the same results
+in the determination of sugar in milk as are obtained by optical
+methods.<a id="FNanchor_216" href="#Footnote_216" class="fnanchor">[216]</a>
+The milk for this purpose is clarified, by precipitating the casein
+with acetic acid in the following manner:
+<span class="pagenum"><a id="Page_295"></a>[Pg 295]</span></p>
+
+<p>Twenty-five cubic centimeters of milk are diluted with an equal
+volume of distilled water, and strong acetic acid added until the
+casein begins to separate. The liquid is heated to boiling and, while
+hot, centrifugated in any convenient machine. The supernatant liquid
+obtained is separated by filtration and the solid matter thrown upon
+the filter and well washed with hot water. The filtrate and washings
+are cooled and completed to a volume of 100 cubic centimeters. This
+liquid is of about the proper dilution for use with the copper cyanid
+reagent. The percentage of sugar determined by this reagent agrees well
+with that obtained by the optical method, when no other sugars than
+lactose are present. If there be a notable difference in the results
+of the two methods other sugars must be looked for. The presence of
+dextrin may be determined by testing a few drops of the clear liquor
+with iodin, which, in the presence of dextrin, gives a reddish color.
+Other sugars are determined by obtaining their osazones. For this
+purpose the filtrate obtained as above should be concentrated until
+the volume is about thirty cubic centimeters. Any solid matter which
+separates during the evaporation is removed by filtration. The osazones
+are precipitated in the manner described in paragraph <b><a href="#P_147">147</a></b>.
+On cooling, the almost solid crystalline mass obtained is placed on a
+filter, washed with a little cold water, the crystals then pressed
+between blotting paper and dried at a temperature of 100°. The dry
+osazones obtained are dissolved in boiling absolute alcohol, of which
+just sufficient is used to obtain complete solution. The alcoholic
+solution is set aside for twelve hours and the separation of a
+crystalline product after that time shows that dextrose or invert sugar
+is present. Milk sugar alone gives no precipitate but only a slight
+amorphous deposit. The lactosazone is precipitated by adding a little
+water to the hot alcoholic solution and the crystals thus obtained
+should be dissolved in boiling absolute alcohol and reprecipitated by
+the addition of water at least three times in order to secure them
+pure. The osazones are identified by their melting points, paragraph
+<b><a href="#P_172">172</a></b>. The first part of this method does not appear to have any
+advantage over the optical process by double dilution (<a href="#Page_278">p. 278</a>),
+and requires more time.
+<span class="pagenum"><a id="Page_296"></a>[Pg 296]</span></p>
+
+<p id="P_262"><b>262. Sugars in Evaporated Milks.</b>—In addition to the lactose
+normally present in evaporated milks the analyst will, in most cases,
+find large quantities of sucrose. The latter sugar is added as a
+preservative and condiment. By reason of the ease with which sucrose
+is hydrolyzed, evaporated milk containing it may have also some invert
+sugar among its contents. A method of examination is desirable,
+therefore, which will secure the determination of lactose, sucrose
+and invert sugar in mixtures. The probability of the development of
+galactose and dextrose during the evaporation and conservation of the
+sample, is not great. The best method of conducting this work is the
+one developed by Bigelow and McElroy.<a id="FNanchor_217" href="#Footnote_217" class="fnanchor">[217]</a>
+The principle on which the method is based rests on the fact that in
+certain conditions, easily supplied, the sucrose and invert sugar
+present in a sample may be entirely removed by fermentation and the
+residual lactose secured in an unchanged condition. The lactose is
+finally estimated by one of the methods already described.</p>
+
+<p>The details of the process follow:</p>
+
+<p>On opening a package of evaporated milk, its entire contents are
+transferred to a dish and well mixed. Several portions of about
+twenty-five grams each are placed in flasks marked at 100 cubic
+centimeters. To each of the flasks enough water is added to bring
+all the sugars into solution and normal rotation is made certain by
+boiling. After cooling, the contents of the flasks are clarified by
+mercuric iodid in acetic acid solution. The clarifying reagent is
+prepared by dissolving fifty-three grams of potassium iodid, twenty-two
+grams of mercuric chlorid, and thirty-two cubic centimeters of
+strongest acetic acid in water, mixing the solutions and completing
+the volume to one liter. The clarification is aided by the use of
+alumina cream (<b><a href="#P_84">84</a></b>). The flask is filled to the mark, and the
+contents well shaken and poured on a filter. After rejecting the first
+portion of the filtrate the residue is polarized in the usual manner.
+Two or more separate portions of the sample are dissolved in water in
+flasks of the size mentioned, heated to 55°, half a cake of compressed
+yeast added to each and the temperature kept at 55° for five hours.
+The residue in each flask is treated as above described, the mercuric
+<span class="pagenum"><a id="Page_297"></a>[Pg 297]</span>
+solution being added before cooling to prevent the fermentative action
+of the yeast, and the polarization noted.</p>
+
+<p>By this treatment the sucrose is completely inverted, while the
+lactose is not affected. The percentage of sucrose is calculated by
+the formulas given in paragraph <b><a href="#P_94">94</a></b>, using the factor 142.6. At
+the temperature noted the yeast exercises no fermentative, but only a
+diastatic action.</p>
+
+<p>In each case the volume of the precipitated milk solids is determined
+by the double dilution method, and the proper correction made (<a href="#Page_278">p. 278</a>).
+The lactose remaining is determined by chemical or optical methods,
+but it is necessary, in all cases where invert sugar is supposed to be
+present, to determine the total reducing sugars in the original sample
+as lactose. If the quantity thus determined and the amount of sucrose
+found as above are sufficient to produce the rotation observed in the
+first polarization, it is evident that no invert sugar is present. When
+the polarization observed is less than is equivalent to the quantity
+of sugar found, invert sugar is present, which tends to diminish the
+rotation produced by the other sugars. In this case it is necessary to
+remove both the sucrose and invert sugar by a process of fermentation,
+which will leave the lactose unchanged.</p>
+
+<p>This is accomplished by conducting the fermentation in the presence
+of potassium fluorid, which prevents the development of the lactic
+ferments. For this purpose 350 grams of the evaporated milk are
+dissolved in water and the solution boiled to secure the normal
+rotation of the lactose. After cooling to 80°, the casein is thrown
+down by adding a solution containing about four grams of glacial
+phosphoric acid and keeping the temperature at 80° for about fifteen
+minutes. After cooling to room temperature, the volume is completed
+to one liter with water, well shaken and poured onto a filter. An
+aliquot part of the filtrate is nearly neutralized with a noted volume
+of potassium hydroxid. Enough water is added to make up, with the
+volume of potassium hydroxid used, the total space occupied by the
+precipitated solid, corresponding to that part of the filtrate, and if
+necessary, refilter. The volume occupied by the precipitated solids is
+easily determined by polarization and double dilution. The filtrate,
+<span class="pagenum"><a id="Page_298"></a>[Pg 298]</span>
+obtained from the process described above, is placed in portions of
+100 cubic centimeters each in 200 cubic centimeter flasks with about
+twenty milligrams of potassium fluorid in solution, and half a cake of
+compressed yeast. The yeast is broken up and evenly distributed, and
+the fermentation is allowed to proceed for ten days at a temperature
+of from 25° to 30°. At the end of this time experience has shown that
+all of the sucrose and invert sugar has disappeared, but the lactose
+remains intact. The flasks are filled to the mark with water and the
+lactose determined by chemical or optical methods. By comparing the
+data obtained from the estimation of the total reducing sugars before
+fermentation or inversion and the estimation of the lactose after
+fermentation, the quantity of invert sugar is easily calculated. The
+experience of this laboratory shows that invert sugar is rarely present
+in evaporated milks, which is an indication that the sucrose added
+thereto does not generally suffer hydrolysis. The mean percentage of
+added sucrose found in evaporated milks is about forty.</p>
+
+<h3>SEPARATION AND DETERMINATION<br> OF STARCH.</h3>
+
+<p><b>263. Occurrence.</b>—Many bodies containing starch are presented
+for the consideration of the agricultural analyst. First in importance
+are the cereals, closely followed by the starchy root crops. Many
+spices and other condiments also contain starchy matters. In the sap
+of some plants, for instance sorghum, at certain seasons, considerable
+quantities of starch occur. In the analysis of cereals and other
+feeding stuffs, it has been the usual custom to make no separate
+determination of starch, but to put together all soluble carbohydrates
+and estimate their percentage by subtracting from 100 the sum of the
+percentages of the other constituents of the sample. This aggregated
+mass has been known as nitrogen-free extract. Recent advances in
+methods of investigation render it advisable to determine the
+starch and pentosan carbohydrates separately and to leave among the
+undetermined bodies the other unclassed substances, chiefly of a
+carbohydrate nature, soluble in boiling dilute acid and alkali.
+<span class="pagenum"><a id="Page_299"></a>[Pg 299]</span></p>
+
+<p><b>264. Separation of Starch.</b>—Starch being insoluble in its natural
+state, it is impossible to separate it from the other insoluble matters
+of plants by any known process. In bringing it into solution it
+undergoes certain changes of an unknown nature, but tending to produce
+a dextrinoid body. Nevertheless, in order to procure the starch in a
+state of purity suited to analytical processes, it becomes necessary
+to dissolve the starch from the other insoluble bodies that naturally
+accompany it. As has been shown in preceding paragraphs, there are only
+two methods of securing the solution of starch which fully meet the
+conditions of accurate analysis. These are the methods depending on the
+use of diastatic ferments and on the employment of heat and pressure
+in the presence of water. These two processes have been described in
+considerable detail in paragraphs <b><a href="#P_179">179-181</a></b>. It is important, in
+starch determinations, to remove from the sample the sugar and other
+substances soluble in water and also the oils, when present in large
+quantities, before subjecting it to the processes for rendering the
+starch soluble.</p>
+
+<p><b>265. Desiccation of Amyliferous Bodies.</b>—The removal of
+sugars and oils is best secured in amyliferous substances after they
+are deprived of their moisture. As has already been suggested, the
+desiccation should be commenced at a low temperature, not above 60°,
+and continued at that point until the chief part of the water has
+escaped. The operation may be conducted in one of the ways already
+described (<a href="#Page_12">pp. 12-27</a>). There is great difference of opinion
+among analysts in respect of the degree of temperature to which the sample
+should be finally subjected, but for the purposes here in view, it will
+not be found necessary to go above 105°. Before beginning the operation
+the sample should be as finely divided as possible, and at its end the
+dried residue should be ground and passed through a sieve of half a
+millimeter mesh.</p>
+
+<p><b>266. Indirect Method of Determining: Water in Starch.</b>—It is
+claimed by Block<a id="FNanchor_218" href="#Footnote_218" class="fnanchor">[218]</a>
+that it is necessary to dry starch at 160° in order to get complete
+dehydration. Wet starch as deposited with its maximum content of water
+has nine molecules thereof, <i>viz.</i>, <b>C₆H₁₀O₅ + 9H₂O</b>. Ordinary
+commercial starch has about eighteen per cent of water with a formula
+of <b>C₆H₁₀O₅ + 2H₂O</b>.
+<span class="pagenum"><a id="Page_300"></a>[Pg 300]</span></p>
+
+<p>The percentage of water may be determined by Block’s feculometer or
+Block’s dose-fécule. The first apparatus determines the percentage of
+anhydrous starch by volume, and the second by weight.</p>
+
+<p>Block’s assumption that starch can absorb only fifty per cent of its
+weight of water is the basis of the determination.</p>
+
+<p>A noted weight of starch is rubbed up with water until saturated, the
+water poured off, the starch weighed, dried on blotting paper until it
+gives off no more moisture and again weighed. Half of the lost weight
+is water, from which the original per cent of water can be calculated.
+This at best seems to be a rough approximation and not suited to
+rigorous scientific determination.</p>
+
+<p><b>267. Removal of Oil and Sugar.</b>—The dried, finely powdered
+sample, obtained as described above, is placed in any convenient
+extractor (<b><a href="#P_33">33-43</a></b>) and the oil or fat it contains removed by
+the usual solvents. For ordinary purposes, even with cereals, this
+preliminary extraction of the oil is not necessary, but it becomes so
+with oily seeds containing starch. The sugar is subsequently removed
+by extraction with eighty per cent alcohol and the residue is then
+ready for the extraction of the starch. In most cases the extraction
+with alcohol will be found sufficient. In some bodies, for instance
+the sweet potato (batata), the quantity of sugar present is quite
+large, and generally some of it is found. If not present in appreciable
+amount, the alcohol extraction may also be omitted. The sample having
+been prepared as indicated, the starch may be brought into solution by
+one of the methods described in paragraphs <b><a href="#P_179">179-181</a></b>, preference
+being given to the aqueous digestion in an autoclave. The dissolved
+starch is washed out of the insoluble residue and determined by optical
+or chemical methods <b><a href="#P_186">186-194</a></b>.</p>
+
+<p><b>268. Preparation of Diastase for Starch Solution.</b>—The methods
+of preparing malt extract for use in starch analysis have been
+described in paragraph <b><a href="#P_179">179</a></b>. If a purer form of diastase is
+desired it may be prepared by following the directions given by Long
+and Baker.<a id="FNanchor_219" href="#Footnote_219" class="fnanchor">[219]</a>
+Digest 200 grams of ground malt for twenty-four hours
+<span class="pagenum"><a id="Page_301"></a>[Pg 301]</span>
+with three parts of twenty per cent alcohol. Separate the extract
+by filtration and to the filtrate add about one and a half liters
+of ninety-three per cent alcohol and stir vigorously. After the
+precipitate has subsided the supernatant alcohol is removed by a
+syphon, the precipitate is brought onto a filter and washed with
+alcohol of a strength gradually increasing to anhydrous, and finally
+with anhydrous ether. The diastase is dried in a vacuum over sulfuric
+acid and finally reduced to a fine powder before using. Thus prepared,
+it varies in appearance from a white to a slightly brownish powder.
+Made at different times and from separate portions of malt, it may show
+great differences in hydrolytic power.</p>
+
+<p><b>269. Estimation of Starch in Potatoes by Specific Gravity.</b>—A
+roughly approximate determination of the quantity of starch in potatoes
+can be made by determining their specific gravity. Since the specific
+gravity of pure starch is 1.65, it follows that the richer a potato is
+in starch the higher will be its specific gravity. The specific weight
+of substances like potatoes is conveniently determined by suspending
+them in water by a fine thread attached to the upper hook of a balance
+pan. There may be a variation of the percentage of other constituents
+in potatoes as well as of starch, and therefore the data obtained from
+the following table can only be correct on the assumption that the
+starch is the only variable. In practice, errors amounting to as much
+as two per cent may be easily made, and therefore the method is useful
+only for agronomic and commercial and not for scientific purposes. The
+method is especially useful in the selection of potatoes of high starch
+content for planting. The table is constructed on the weight in grams
+in pure water of 10000 grams of potatoes and the corresponding per
+cents of dry matter and starch are given. It is not always convenient
+to use exactly 10000 grams of potatoes for the determination, but the
+calculation for any given weight is easy.<a id="FNanchor_220" href="#Footnote_220" class="fnanchor">[220]</a></p>
+
+<div class="blockquot">
+<p><i>Example.</i>—Let the weight of a potato in air be 159 grams, and
+its weight in water 14.8 grams.</p>
+
+<p>Then the weight of 10000 grams of potatoes of like nature in water
+would be found from the equation 159: 10000 = 14.8: <i>x</i>.</p>
+
+<p>Whence <i>x</i> = 931 nearly.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_302"></a>[Pg 302]</span>
+In the table the nearest figure to 931 is 930, corresponding to
+24.6 per cent of dry matter and 18.8 per cent of starch. When
+the number found is half way between the numbers given in the
+table the mean of the data above and below can be taken. In
+other positions a proper interpolation can be made if desired but
+for practical purposes the data corresponding to the nearest
+number can be used.</p>
+
+<p class="f120 spa1"><b><span class="smcap">Table for Calculating Starch in Potatoes<br>
+from Specific Gravity.</span></b></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb">10000 grams<br>of potatoes<br>weigh in water.<br>Grams.</th>
+      <th class="tdc_bott bb">Per cent<br>&nbsp; dry matter. &nbsp;</th>
+      <th class="tdc_bott bb">&nbsp; Per cent &nbsp;<br>starch.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">&#8199;750</td>
+      <td class="tdc">19.9</td>
+      <td class="tdc">14.1</td>
+   </tr><tr>
+      <td class="tdc">&#8199;760</td>
+      <td class="tdc">20.1</td>
+      <td class="tdc">14.3</td>
+   </tr><tr>
+      <td class="tdc">&#8199;770</td>
+      <td class="tdc">20.3</td>
+      <td class="tdc">14.5</td>
+   </tr><tr>
+      <td class="tdc">&#8199;780</td>
+      <td class="tdc">20.7</td>
+      <td class="tdc">14.9</td>
+   </tr><tr>
+      <td class="tdc">&#8199;790</td>
+      <td class="tdc">20.9</td>
+      <td class="tdc">15.1</td>
+   </tr><tr>
+      <td class="tdc">&#8199;800</td>
+      <td class="tdc">21.2</td>
+      <td class="tdc">15.4</td>
+   </tr><tr>
+      <td class="tdc">&#8199;810</td>
+      <td class="tdc">21.4</td>
+      <td class="tdc">15.6</td>
+   </tr><tr>
+      <td class="tdc">&#8199;820</td>
+      <td class="tdc">21.6</td>
+      <td class="tdc">15.8</td>
+   </tr><tr>
+      <td class="tdc">&#8199;830</td>
+      <td class="tdc">22.0</td>
+      <td class="tdc">16.2</td>
+   </tr><tr>
+      <td class="tdc">&#8199;840</td>
+      <td class="tdc">22.2</td>
+      <td class="tdc">16.4</td>
+   </tr><tr>
+      <td class="tdc">&#8199;850</td>
+      <td class="tdc">22.4</td>
+      <td class="tdc">16.6</td>
+   </tr><tr>
+      <td class="tdc">&#8199;860</td>
+      <td class="tdc">22.7</td>
+      <td class="tdc">16.9</td>
+   </tr><tr>
+      <td class="tdc">&#8199;870</td>
+      <td class="tdc">22.9</td>
+      <td class="tdc">17.1</td>
+   </tr><tr>
+      <td class="tdc">&#8199;880</td>
+      <td class="tdc">23.1</td>
+      <td class="tdc">17.3</td>
+   </tr><tr class="bb">
+      <td class="tdc">&#8199;890</td>
+      <td class="tdc">23.5</td>
+      <td class="tdc">17.7</td>
+   </tr><tr>
+      <td class="tdc">&#8199;900</td>
+      <td class="tdc">23.7</td>
+      <td class="tdc">17.9</td>
+   </tr><tr>
+      <td class="tdc">&#8199;910</td>
+      <td class="tdc">24.0</td>
+      <td class="tdc">18.2</td>
+   </tr><tr>
+      <td class="tdc">&#8199;920</td>
+      <td class="tdc">24.2</td>
+      <td class="tdc">18.4</td>
+   </tr><tr>
+      <td class="tdc">&#8199;930</td>
+      <td class="tdc">24.6</td>
+      <td class="tdc">18.8</td>
+   </tr><tr>
+      <td class="tdc">&#8199;940</td>
+      <td class="tdc">24.8</td>
+      <td class="tdc">19.0</td>
+   </tr><tr>
+      <td class="tdc">&#8199;950</td>
+      <td class="tdc">25.0</td>
+      <td class="tdc">19.2</td>
+   </tr><tr>
+      <td class="tdc">&#8199;960</td>
+      <td class="tdc">25.2</td>
+      <td class="tdc">19.4</td>
+   </tr><tr>
+      <td class="tdc">&#8199;970</td>
+      <td class="tdc">25.5</td>
+      <td class="tdc">19.7</td>
+   </tr><tr>
+      <td class="tdc">&#8199;980</td>
+      <td class="tdc">25.9</td>
+      <td class="tdc">20.1</td>
+   </tr><tr class="bb">
+      <td class="tdc">&#8199;990</td>
+      <td class="tdc">26.1</td>
+      <td class="tdc">20.3</td>
+   </tr><tr>
+      <td class="tdc">1000</td>
+      <td class="tdc">26.3</td>
+      <td class="tdc">20.5</td>
+   </tr><tr>
+      <td class="tdc">1010</td>
+      <td class="tdc">26.5</td>
+      <td class="tdc">20.7</td>
+   </tr><tr>
+      <td class="tdc">1020</td>
+      <td class="tdc">26.9</td>
+      <td class="tdc">21.1</td>
+   </tr><tr>
+      <td class="tdc">1030</td>
+      <td class="tdc">27.2</td>
+      <td class="tdc">21.4</td>
+   </tr><tr>
+      <td class="tdc">1040</td>
+      <td class="tdc">27.4</td>
+      <td class="tdc">21.6</td>
+   </tr><tr>
+      <td class="tdc">1050</td>
+      <td class="tdc">27.6</td>
+      <td class="tdc">21.8</td>
+   </tr><tr>
+      <td class="tdc">1060</td>
+      <td class="tdc">28.0</td>
+      <td class="tdc">22.2</td>
+   </tr><tr>
+      <td class="tdc">1070</td>
+      <td class="tdc">28.3</td>
+      <td class="tdc">22.5</td>
+   </tr><tr>
+      <td class="tdc">1080</td>
+      <td class="tdc">28.5</td>
+      <td class="tdc">22.7</td>
+   </tr><tr class="bb">
+      <td class="tdc">1090</td>
+      <td class="tdc">28.7</td>
+      <td class="tdc">22.9</td>
+   </tr><tr>
+      <td class="tdc">1100</td>
+      <td class="tdc">29.1</td>
+      <td class="tdc">23.3</td>
+   </tr><tr>
+      <td class="tdc">1110</td>
+      <td class="tdc">29.3</td>
+      <td class="tdc">23.5</td>
+   </tr><tr>
+      <td class="tdc">1120</td>
+      <td class="tdc">29.5</td>
+      <td class="tdc">23.7</td>
+   </tr><tr>
+      <td class="tdc">1130</td>
+      <td class="tdc">29.8</td>
+      <td class="tdc">24.0</td>
+   </tr><tr>
+      <td class="tdc">1140</td>
+      <td class="tdc">30.2</td>
+      <td class="tdc">24.4</td>
+   </tr><tr>
+      <td class="tdc">1150</td>
+      <td class="tdc">30.4</td>
+      <td class="tdc">24.6</td>
+   </tr><tr>
+      <td class="tdc">1160</td>
+      <td class="tdc">30.6</td>
+      <td class="tdc">24.8</td>
+   </tr><tr>
+      <td class="tdc">1170</td>
+      <td class="tdc">31.0</td>
+      <td class="tdc">25.0</td>
+   </tr><tr>
+      <td class="tdc">1180</td>
+      <td class="tdc">31.3</td>
+      <td class="tdc">25.5</td>
+   </tr><tr class="bb">
+      <td class="tdc">1190</td>
+      <td class="tdc">31.5</td>
+      <td class="tdc">25.7</td>
+   </tr><tr>
+      <td class="tdc">1200</td>
+      <td class="tdc">31.7</td>
+      <td class="tdc">25.9</td>
+   </tr><tr>
+      <td class="tdc">1210</td>
+      <td class="tdc">32.1</td>
+      <td class="tdc">26.3</td>
+   </tr><tr>
+      <td class="tdc">1220</td>
+      <td class="tdc">32.3</td>
+      <td class="tdc">26.5</td>
+   </tr><tr>
+      <td class="tdc">1230</td>
+      <td class="tdc">32.5</td>
+      <td class="tdc">26.7</td>
+   </tr><tr>
+      <td class="tdc">1240</td>
+      <td class="tdc">33.0</td>
+      <td class="tdc">27.2</td>
+   </tr><tr>
+      <td class="tdc">1250</td>
+      <td class="tdc">33.2</td>
+      <td class="tdc">27.4</td>
+   </tr><tr>
+      <td class="tdc">1260</td>
+      <td class="tdc">33.4</td>
+      <td class="tdc">27.6</td>
+   </tr><tr>
+      <td class="tdc">1270</td>
+      <td class="tdc">33.6</td>
+      <td class="tdc">27.8</td>
+   </tr><tr>
+      <td class="tdc">1280</td>
+      <td class="tdc">34.1</td>
+      <td class="tdc">28.3</td>
+   </tr><tr class="bb">
+      <td class="tdc">1290</td>
+      <td class="tdc">34.3</td>
+      <td class="tdc">28.5</td>
+   </tr><tr>
+      <td class="tdc">1300</td>
+      <td class="tdc">34.5</td>
+      <td class="tdc">28.7</td>
+   </tr><tr>
+      <td class="tdc">1310</td>
+      <td class="tdc">34.9</td>
+      <td class="tdc">29.1</td>
+   </tr><tr>
+      <td class="tdc">1320</td>
+      <td class="tdc">35.1</td>
+      <td class="tdc">29.3</td>
+   </tr><tr>
+      <td class="tdc">1330</td>
+      <td class="tdc">35.4</td>
+      <td class="tdc">29.6</td>
+   </tr><tr>
+      <td class="tdc">1340</td>
+      <td class="tdc">35.8</td>
+      <td class="tdc">30.0</td>
+   </tr><tr>
+      <td class="tdc">1350</td>
+      <td class="tdc">36.0</td>
+      <td class="tdc">30.2</td>
+   </tr><tr>
+      <td class="tdc">1360</td>
+      <td class="tdc">36.2</td>
+      <td class="tdc">30.4</td>
+   </tr><tr class="bb">
+      <td class="tdc">1370</td>
+      <td class="tdc">36.6</td>
+      <td class="tdc">30.8</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_303"></a>[Pg 303]</span>
+<b>270. Constitution of Cellulose.</b>—The group of bodies known as
+cellulose comprises many members of essentially the same chemical
+constitution but of varying properties. The centesimal composition of
+pure cellulose is shown by the following numbers:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Carbon,</td>
+      <td class="tdr_wsp">44.2</td>
+      <td class="tdl_wsp">per</td>
+      <td class="tdl_wsp">cent</td>
+   </tr><tr>
+      <td class="tdl">Hydrogen,&emsp;&nbsp;</td>
+      <td class="tdr_wsp">6.3</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl">Oxygen,</td>
+      <td class="tdr_wsp">49.5</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="no-indent">corresponding to the formula <b>C₆H₁₀H₅</b>.</p>
+
+<p>According to the view of Cross and Bevan, cellulose conforms in respect
+of its ultimate constitutional groups to the general features of the
+simple carbohydrates, but differs from them by reason of a special
+molecular configuration resulting in a suppression of the activity of
+constituent groups in certain respects, and an increase in activity of
+others.<a id="FNanchor_221" href="#Footnote_221" class="fnanchor">[221]</a></p>
+
+<p><b>271. Fiber and Cellulose.</b>—The carbohydrates of a plant
+insoluble in water are not composed exclusively of starch. There are,
+in addition to starch, pentosan fibers yielding pentose sugars on
+hydrolysis and furfuraldehyd on distillation with a strong acid. The
+quantitive methods for estimating the pentosan bodies are given in
+paragraphs <b><a href="#P_150">150-157</a></b>. The method to be preferred
+is that of Krug (<b><a href="#P_155">155</a></b>).</p>
+
+<p>In the estimation of cattlefoods and of plant substances in general the
+residue insoluble in dilute boiling acid and alkali is called crude or
+indigestible fiber.</p>
+
+<p>The principle on which the determination depends rests on the
+assumption that all the protein, starch and other digestible
+carbohydrates will be removed from the sample by successive digestion
+at a boiling temperature with acid and alkali solutions of a given
+strength. It is evident that the complex body obtained by the treatment
+outlined above is not in any sense a definite chemical compound, but it
+may be considered as being composed partly of cellulose.</p>
+
+<p id="P_272"><b>272. Official Method of Determining Crude Fiber.</b>—The method
+of estimating crude fiber, adopted by the Association of Official
+Agricultural Chemists, is as follows:
+<a id="FNanchor_222" href="#Footnote_222" class="fnanchor">[222]</a></p>
+
+<p><span class="pagenum"><a id="Page_304"></a>[Pg 304]</span>
+Extract two grams of the substance with ordinary ether, at least
+almost completely, or use the residue from the determination of the
+ether extract. To this residue, in a half liter flask, add 200 cubic
+centimeters of boiling 1.25 per cent sulfuric acid; connect the flask
+with an inverted condenser, the tube of which passes only a short
+distance beyond the rubber stopper into the flask. Boil at once, and
+continue the boiling for thirty minutes. A blast of air conducted into
+the flask may serve to reduce the frothing of the liquid. Filter, wash
+thoroughly with boiling water until the washings are no longer acid,
+rinse the substance back into the same flask with 200 cubic centimeters
+of a boiling 1.25 per cent solution of sodium hydroxid, free or nearly
+free of sodium carbonate, boil at once and continue the boiling for
+thirty minutes in the same manner as directed above for the treatment
+with acid. Filter into a gooch, and wash with boiling water until the
+washings are neutral, dry at 110°, weigh and incinerate completely. The
+loss of weight is crude fiber.</p>
+
+<p>The filter used for the first filtration may be linen, one of the forms
+of glass wool or asbestos filters, or any other form that secures clear
+and reasonably rapid filtration. The solutions of sulfuric acid and
+sodium hydroxid are to be made up of the specified strength, determined
+accurately by titration and not merely from specific gravity.</p>
+
+<p>The experience of this laboratory has shown that results practically
+identical with those got as above, are obtained by conducting the
+digestions in hard glass beakers covered with watch glasses. The ease
+of manipulation in the modification of the process just mentioned is a
+sufficient justification for its use.</p>
+
+<p><b>273. Separation of Cellulose.</b>—Hoppe-Seyler observed that
+cellulose, when melted with the alkalies at a temperature as high as
+200°, was not sensibly attacked.<a id="FNanchor_223" href="#Footnote_223" class="fnanchor">[223]</a></p>
+
+<p>Lange has based a process for determining cellulose on this
+observation.<a id="FNanchor_224" href="#Footnote_224" class="fnanchor">[224]</a></p>
+
+<p>The process, as improved by him, is carried out as follows:</p>
+
+<p>From five to ten grams of the substance are moistened with water and
+placed in a porcelain dish with about three times their weight of
+caustic alkali free of nitrates and about twenty cubic centimeters of
+water. The porcelain dish should be deep and crucible shaped and should
+<span class="pagenum"><a id="Page_305"></a>[Pg 305]</span>
+be placed in an oil-bath, the temperature of which is easily
+controlled. The contents of the dish are stirred with the thermometer
+bulb until all foaming ceases and the temperature of the mixture is
+then kept at from 175° to 180° for an hour. After the melt has cooled
+to 80° about seventy-five cubic centimeters of hot water are added to
+bring it into solution and it is then allowed to cool. The solution is
+acidified with sulfuric and placed in large centrifugal tubes. After
+being made slightly alkaline with soda lye, the tubes are subjected
+to continued energetic centrifugal action until the cellulose is
+separated. The supernatant liquid can be nearly all poured off and the
+separated cellulose is broken up, treated with hot water and again
+separated by centrifugal action. The cellulose is finally collected
+upon the asbestos felt, washed with hot water, alcohol and ether, dried
+and weighed. With a little practice it is possible to complete the
+separation of cellulose in two and one-half hours.</p>
+
+<p><b>274. Solubility of Cellulose.</b>—Cellulose resembles starch in
+its general insolubility, but, unlike starch, it may be dissolved in
+some reagents and afterwards precipitated practically unchanged or in a
+state of hydration. One of the simplest solvents of cellulose is zinc
+chlorid in concentrated aqueous solution.</p>
+
+<p>The solution is accomplished with the aid of heat, adding one part by
+weight of cotton to six parts of zinc chlorid dissolved in ten parts of
+water.</p>
+
+<p>A homogeneous sirup is obtained by this process, which is used in the
+arts for making the carbon filaments of incandescent electric lamps.</p>
+
+<p>In preparing the thread of cellulose, the solution, obtained as
+described above, is allowed to flow, in a fine stream, into alcohol,
+whereby a cellulose hydrate is precipitated, which is freed from zinc
+hydroxid by digesting in hydrochloric acid.</p>
+
+<p>Hydrochloric acid may be substituted for water in preparing the reagent
+above noted, whereby a solvent is secured which acts upon cellulose
+readily in the cold.</p>
+
+<p>A solution of ammoniacal cupric oxid is one of the best solvents for
+cellulose. The solution should contain from ten to fifteen per cent of
+ammonia and from two to two and a half of cupric oxid.
+<span class="pagenum"><a id="Page_306"></a>[Pg 306]</span></p>
+
+<p>In the preparation of this reagent, ammonium chlorid is added to a
+solution of cupric salt and then sodium hydroxid in just sufficient
+quantity to precipitate all of the copper as hydroxid. The precipitate
+is well washed on a linen filter, squeezed as dry as possible and
+dissolved in ammonia of 0.92 specific gravity. The cellulose is readily
+precipitated from the solution in cuprammonium by the addition of
+alcohol, sodium chlorid, sugar, or other dehydrating agents. Solutions
+of cellulose are used in the arts for many purposes.<a id="FNanchor_225" href="#Footnote_225" class="fnanchor">[225]</a></p>
+
+<p><b>275. Qualitive Reactions for Detecting Cellulose.</b>—Cellulose
+may be identified by its resistance to the action of oxidizing agents,
+to the halogens and to alkaline solutions. It is further recognized by
+the sirupy or gelatinous solutions it forms with the solvents mentioned
+above. The cellulose hydrates precipitated from solutions have in some
+instances the property of forming a blue color with iodin.</p>
+
+<p>A characteristic reaction of cellulose is secured as follows: To a
+saturated solution of zinc hydrochlorate, of 2.00 specific gravity, are
+added six parts by weight of potassium iodid dissolved in ten parts
+of water and this solution is saturated with iodin. Cellulose treated
+with this reagent is at once stained a deep blue violet color.<a id="FNanchor_226" href="#Footnote_226" class="fnanchor">[226]</a>
+For the characteristics of cellulose occurring in wood the researches of
+Lindsey may be consulted.<a id="FNanchor_227" href="#Footnote_227" class="fnanchor">[227]</a></p>
+
+<p><b>276. More Rarely Occurring Carbohydrates.</b>—It is not possible
+here to give more space to the rarer forms of carbohydrates, to which
+the attention of the agricultural analyst may be called. Nearly a
+hundred kinds of sugars alone have been detected in the plant world.
+For descriptions of the properties of these bodies and the methods of
+their detection and determination, the standard works on carbohydrates
+may be consulted.<a id="FNanchor_228" href="#Footnote_228" class="fnanchor">[228]</a></p>
+
+<h3>AUTHORITIES CITED IN PART THIRD.</h3>
+
+<div class="footnotes">
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_170" href="#FNanchor_170" class="label">[170]</a>
+Vines; Physiology of Plants. Nägeli; Beiträge zur näheren
+Kenntniss der Stärkegruppe.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_171" href="#FNanchor_171" class="label">[171]</a>
+Bulletin 5, Department of Agriculture, Division of Chemistry, pp. 191
+et seq.: Bulletin 25, New Hampshire Experiment Station.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_172" href="#FNanchor_172" class="label">[172]</a>
+Spencer; Handbook for Sugar Manufacturers, p. 31.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_173" href="#FNanchor_173" class="label">[173]</a>
+Vid. op. cit. supra, pp. 102, 108.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_307"></a>[Pg 307]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_174" href="#FNanchor_174" class="label">[174]</a>
+Journal of the American Chemical Society, Vol. 16, p. 677.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_175" href="#FNanchor_175" class="label">[175]</a>
+Botanical Gazette, Vol. 12, No. 3.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_176" href="#FNanchor_176" class="label">[176]</a>
+Bulletin de l’Association des Chimistes de Sucrerie et de
+Distillerie, Tome 13, p. 133.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_177" href="#FNanchor_177" class="label">[177]</a>
+Journal of Analytical and Applied Chemistry, Vol. 4, p. 381.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_178" href="#FNanchor_178" class="label">[178]</a>
+Spencer’s Handbook for Sugar Manufacturers, pp. 30 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_179" href="#FNanchor_179" class="label">[179]</a>
+Bulletin de l’Association des Chimistes de Sucrerie et de
+Distillerie, Tome 13, p. 292.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_180" href="#FNanchor_180" class="label">[180]</a>
+Vid. op. cit. supra, Tome 2, p. 369.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_181" href="#FNanchor_181" class="label">[181]</a>
+Dosage du Sucre Cristallisable dans la Betterave, pp. 117
+et seq.: Journal of the American Chemical Society, Vol. 16, p. 266.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_182" href="#FNanchor_182" class="label">[182]</a>
+Neue Zeitschrift für Rübenzucker-Industrie. Band 3, S. 342; Band 14, S.
+286: Zeitschrift des Vereins für die Rübenzucker-Industrie, 1876, S.
+692: Dingler’s Polytechnisches Journal, Band 232, S. 461.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_183" href="#FNanchor_183" class="label">[183]</a>
+Sidersky: Traité d’ Analyse des Matières Sucrées, p. 304.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_184" href="#FNanchor_184" class="label">[184]</a>
+Neue Zeitschrift für Rübenzucker-Industrie, Band 14, S. 286.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_185" href="#FNanchor_185" class="label">[185]</a>
+Zeitschrift des Vereins für die Rübenzucker-Industrie, Band 32, S. 861.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_186" href="#FNanchor_186" class="label">[186]</a>
+Spencer’s Handbook for Sugar Manufacturers, p. 42.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_187" href="#FNanchor_187" class="label">[187]</a>
+Bulletin No. 4 of the Chemical Society of Washington, pp. 22, et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_188" href="#FNanchor_188" class="label">[188]</a>
+Vid. op. et loc. cit. 7.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_189" href="#FNanchor_189" class="label">[189]</a>
+Chemiker-Zeitung, Band 19, S. 1830.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_190" href="#FNanchor_190" class="label">[190]</a>
+Vid. op cit. supra, S. 1784.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_191" href="#FNanchor_191" class="label">[191]</a>
+Vid. op. cit. supra, S. 1829.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_192" href="#FNanchor_192" class="label">[192]</a>
+Zeitschrift des Vereins für die Rübenzucker-Industrie, 1895, S. 844.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_193" href="#FNanchor_193" class="label">[193]</a>
+Journal des Fabricants de Sucre, 1895, No. 33.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_194" href="#FNanchor_194" class="label">[194]</a>
+Journal of the American Chemical Society, Vol. 2, p. 387:
+Agricultural Science, Feb. 1892.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_195" href="#FNanchor_195" class="label">[195]</a>
+American Chemical Journal, Vol. 13, p. 24.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_196" href="#FNanchor_196" class="label">[196]</a>
+Tucker; Manual of Sugar Analysis, p. 287: Wiechmann; Sugar Analysis, p. 51.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_197" href="#FNanchor_197" class="label">[197]</a>
+Sidersky; vid. op. cit., 14, p. 197.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_198" href="#FNanchor_198" class="label">[198]</a>
+Journal of the American Chemical Society, Vol. 18, p. 81:
+Allen; Commercial Organic Analysis, Vol. 1, p. 291.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_199" href="#FNanchor_199" class="label">[199]</a>
+Handbuch der Physiologisch- und Pathologisch-Chemischen Analyse, S. 286.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_200" href="#FNanchor_200" class="label">[200]</a>
+Kühne und Chittenden; American Chemical Journal, Vol. 6, p. 45.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_201" href="#FNanchor_201" class="label">[201]</a>
+Vid. op. cit. supra, p. 289.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_202" href="#FNanchor_202" class="label">[202]</a>
+Analyst, Vol. 13, p. 64.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_203" href="#FNanchor_203" class="label">[203]</a>
+Journal American Chemical Society, Vol. 18, p. 438.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_308"></a>[Pg 308]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_204" href="#FNanchor_204" class="label">[204]</a>
+School of Mines Quarterly, Vols. 11 and 12.</p>
+
+<p>In a later method (School of Mines Quarterly, Vol. 13, No. 3)
+Wiechman describes the separation of the sugars by one polariscopic and
+two gravimetric determinations, one before and one after inversion.
+The polariscopic examination is made in a ten per cent solution at a
+temperature of 20°. The gyrodynats of sucrose, dextrose and levulose
+at the temperature mentioned are fixed at 66.5, 53.5 and -81.9
+respectively. The gravimetric determinations are conducted according
+to the methods already described. In the formulas for calculating
+the results <i>a</i> represents sucrose, <i>b</i> reducing sugars,
+<i>x</i> the dextrose, <i>y</i> the levulose, and <i>d</i> the observed
+polarization expressed in degrees angular measure. The gyrodynats
+of sucrose, dextrose and levulose divided by 100 are represented by
+<i>s</i>, <i>d</i> and <i>l</i>. The calculations are made from the
+following formulas:</p>
+
+<p class="center">(<i>as</i> + <i>xd</i>) - <i>yl</i> = <i>p</i>.<br>
+(<i>as</i> + <i>xd</i>) = <i>p</i> + <i>yl</i>.<br>
+<i>xd</i> = <i>p</i> + <i>yl</i> - <i>as</i>.</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>x</i> = &nbsp;</td>
+      <td class="tdc bb"><i>p</i> + <i>yl</i> - <i>as</i></td>
+   </tr><tr>
+      <td class="tdc"><i>d</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p>In this calculation the gyrodynat of levulose is about ten degrees
+lower than that of most authorities.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_205" href="#FNanchor_205" class="label">[205]</a>
+Vid. op. cit., 23, Band 24, S. 869.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_206" href="#FNanchor_206" class="label">[206]</a>
+Vid. op. cit. supra, 1888, S. 782.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_207" href="#FNanchor_207" class="label">[207]</a>
+Neue Zeitschrift für Rübenzucker-Industrie, Band 35, S. 166.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_208" href="#FNanchor_208" class="label">[208]</a>
+Journal of the American Chemical Society, Vol. 2, p. 399: Science,
+Oct. 1, 1881: Proceedings American Association for the Advancement of
+Science, 1881, p. 61: Sugar Cane, Vol. 13, p. 533, pp. 61-66.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_209" href="#FNanchor_209" class="label">[209]</a>
+Wiley and McElroy; Agricultural Science, Vol. 6, p. 57.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_210" href="#FNanchor_210" class="label">[210]</a>
+Chemical News, Vol. 46, p. 175.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_211" href="#FNanchor_211" class="label">[211]</a>
+Vid. op. cit, 14, p. 352.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_212" href="#FNanchor_212" class="label">[212]</a>
+Vid. op. et loc. cit., 41.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_213" href="#FNanchor_213" class="label">[213]</a>
+Vid. op. cit., 41, Vol. 65, p. 169.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_214" href="#FNanchor_214" class="label">[214]</a>
+Zeitschrift des Vereins für die Rübenzucker-Industrie, 1884, S. 854.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_215" href="#FNanchor_215" class="label">[215]</a>
+Bulletin 46, Division of Chemistry, U. S. Department of Agriculture, p. 60.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_216" href="#FNanchor_216" class="label">[216]</a>
+The Analyst, Vol. 20, p. 121.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_217" href="#FNanchor_217" class="label">[217]</a>
+Journal American Chemical Society, Vol. 15, p. 668.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_218" href="#FNanchor_218" class="label">[218]</a>
+Comptes rendus, Tome 118, p. 147.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_219" href="#FNanchor_219" class="label">[219]</a>
+Journal of the Chemical Society, Transactions, 1895, p. 735.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_220" href="#FNanchor_220" class="label">[220]</a>
+Die agrikultur-chemische Versuchsstation, Halle, a/S., S. 114.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_221" href="#FNanchor_221" class="label">[221]</a>
+Cellulose, p. 77.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_222" href="#FNanchor_222" class="label">[222]</a>
+Vid. op. cit., 46, p. 63.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_223" href="#FNanchor_223" class="label">[223]</a>
+Zeitschrift für physiologische Chemie, Band 13, S. 84.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_224" href="#FNanchor_224" class="label">[224]</a>
+Zeitschrift für angewandte Chemie, 1895, S. 561.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_225" href="#FNanchor_225" class="label">[225]</a>
+Vid. op. cit., 52, pp. 8 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_226" href="#FNanchor_226" class="label">[226]</a>
+Vid. op. cit. supra, p. 15.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_227" href="#FNanchor_227" class="label">[227]</a>
+Composition of Wood, Agricultural Science, Vol. 7, pp. 49, 97 and 161.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_228" href="#FNanchor_228" class="label">[228]</a>
+Tollens; Handbuch der Kohlenhydrate: von Lippmann; Chemie der Zuckerarten.</p>
+</div>
+</div>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum"><a id="Page_309"></a>[Pg 309]</span></p>
+<h2 class="nobreak">PART FOURTH.<br>
+<span class="h_subtitle">FATS AND OILS.</span></h2>
+</div>
+
+<p><b>277. Nomenclature.</b>—The terms fat and oil are often used
+interchangeably and it is difficult in all cases to limit definitely
+their application. The consistence of the substance at usual room
+temperatures may be regarded as a point of demarcation. The term fat,
+in this sense, is applied to glycerids which are solid or semi solid,
+and oil to those which are quite or approximately liquid. A further
+classification is found in the origin of the glycerids, and this gives
+rise to the groups known as animal or vegetable fats and oils. In this
+manual, in harmony with the practices mentioned above, the term fat
+will be used to designate an animal or vegetable glycerid which is
+solid, and the term oil one which is liquid at common room temperature,
+<i>viz.</i>, about 20°. There are few animal oils, and few vegetable
+fats when judged by this standard, and it therefore happens that the
+term oil is almost synonymous with vegetable glycerid and fat with
+a glycerid of animal origin. Nearly related to the fats and oils is
+the group of bodies known as resins and waxes. This group of bodies,
+however, can be distinguished from the fats and oils by chemical
+characteristics. The waxes are ethers formed by the union of fatty
+acids and alcohols of the ethane, and perhaps also of the ethylene
+series.<a id="FNanchor_229" href="#Footnote_229" class="fnanchor">[229]</a>
+This chemical difference is not easily expressed and the terms
+themselves often add confusion to the meaning, as for instance, japan
+wax is composed mostly of fats, and sperm oil is essentially a wax.</p>
+
+<p><b>278. Composition.</b>—Fats and oils are composed chiefly of salts
+produced by the combination of the complex base glycerol with the fat
+acids. Certain glycerids, as the lecithins, contain also phosphorus
+in organic combinations, nitrogen, and possibly other inorganic
+constituents in organic forms. By the action of alkalies the glycerids
+are easily decomposed, the acid combining with the inorganic base and
+<span class="pagenum"><a id="Page_310"></a>[Pg 310]</span>
+the glycerol becoming free. The salts thus produced form the soaps
+of commerce and the freed base, when collected and purified, is the
+glycerol of the trade.</p>
+
+<p>When waxes are decomposed by alkalies, fatty acids and alcohols of the
+ethane series are produced.</p>
+
+<p>The natural glycerids formed from glycerol, which is a trihydric
+(triatomic) alcohol, are found in the neutral state composed of three
+molecules of the acid, united with one of the base. If R represent the
+radicle of the fat acid the general formula for the chemical process by
+which the salt is produced is:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdc" colspan="2">Glycerol.</td>
+      <td class="tdc">&nbsp; Acid.</td>
+      <td class="tdc" colspan="2">Salt.</td>
+      <td class="tdc">&emsp;Water.</td>
+   </tr><tr>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdl">O.H</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdl">O.R</td>
+      <td class="tdc">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">C₃H₅</td>
+      <td class="tdl">O.H</td>
+      <td class="tdl_wsp">+ 3R.OH =</td>
+      <td class="tdl_wsp">C₃H₅</td>
+      <td class="tdl">O.R</td>
+      <td class="tdl_wsp">+ 3H₂O.</td>
+   </tr><tr>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdl">O.H</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdl">O.R</td>
+      <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The resulting salts are called triglycerids or neutral glycyl
+ethers.<a id="FNanchor_230" href="#Footnote_230" class="fnanchor">[230]</a>
+In natural animal and vegetable products, only the neutral salts are
+found, the mono- and diglycerids resulting from artificial synthesis.
+For this reason the prefix tri is not necessarily used in designating
+the natural glycerids, stearin, for instance, meaning the same as tristearin.</p>
+
+<p><b>279. Principal Glycerids.</b>—The most important glycerids which
+the analyst will find are the following:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Olein,</td>
+      <td class="tdl_ws1">C₃H₅O(O.C₁₈H₃₃O)₃.</td>
+   </tr><tr>
+      <td class="tdl">Stearin,</td>
+      <td class="tdl_ws1">C₃H₅O(O.C₁₈H₃₅)₃.</td>
+   </tr><tr>
+      <td class="tdl">Palmitin,</td>
+      <td class="tdl_ws1">C₃H₅O(O.C₁₆H₃₁O)₃.</td>
+   </tr><tr>
+      <td class="tdl">Linolein,</td>
+      <td class="tdl_ws1">C₃H₅O(O.C₁₈H₃₁O)₃.</td>
+   </tr><tr>
+      <td class="tdl">Butyrin,</td>
+      <td class="tdl_ws1">C₃H₅O(O.C₄H₇O)₃.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Olein is the chief constituent of most oils; palmitin is found in palm
+oil and many other natural glycerids; stearin is a leading constituent
+of the fats of beeves and sheep, and butyrin is a characteristic
+constituent of butter, which owes its flavor largely to this glycerid
+and its nearly related concomitants.</p>
+
+<p id="P_280"><b>280. Extraction of Oils and Fats.</b>—Preparatory to a physical
+and chemical study of the fats and oils is their separation from the
+other organic matters with which they may be associated. In the case of
+animal tissues this is usually accomplished by the application of heat.
+<span class="pagenum"><a id="Page_311"></a>[Pg 311]</span>
+The operation known as rendering may be conducted in many different
+ways. For laboratory purposes, the animal tissues holding the fat
+are placed in a convenient dish and a degree of heat applied which
+will liquify all the fat particles and free them from their investing
+membranes. The temperature employed should be as low as possible to
+secure the desired effect, but fats can be subjected for some time to
+a heat of a little more than 100°, without danger of decomposition.
+The direct heat of a lamp, however, should not be applied, since it
+is difficult to avoid too high a temperature at the point of contact
+of the flame and dish. The dry heat of an air-bath or rendering in an
+autoclave or by steam is preferable. The residual animal matter is
+subjected to pressure and the combined liquid fat freed from foreign
+matters by filtering through a jacket filter, which is kept at a
+temperature above the solidifying point of the contents.</p>
+
+<p>On a large scale, as in rendering lard, the fat is separated by steam
+in closed vats which are strong enough to withstand the steam pressure
+employed. For analytical purposes it is best to extract the fat from
+animal tissues in the manner described, since the action of solvents
+is slow on fat particles enveloped in their containing membranes, and
+the fats, when extracted, are liable to be contaminated with extraneous
+matters. In dried and ground flesh meal, however, the fat may be
+extracted with the usual solvents. For the quantitive determination of
+fat in bones or flesh, the sample, as finely divided as possible, is
+thoroughly dried, and the fat separated from an aliquot finely powdered
+portion by extraction with chloroform, ether, or petroleum. The action
+of anhydrous ether on dried and powdered animal matters is apparently
+a continuous one. Dormeyer has shown that even after an extraction of
+several months additional matter goes into solution.<a id="FNanchor_231" href="#Footnote_231" class="fnanchor">[231]</a>
+The fat in such cases can be determined by saponification with
+alcoholic potash and the estimation of the free fatty acids produced.</p>
+
+<p>From vegetable substances, such as seeds, the fat is extracted either
+by pressure or by the use of solvents. For quantitive purposes, only
+solvents are employed. The dry, finely ground material is exhausted
+with anhydrous ether or petroleum spirit, in one of the convenient
+<span class="pagenum"><a id="Page_312"></a>[Pg 312]</span>
+forms of apparatus already described (<b><a href="#P_33">33->43</a></b>). In very
+oily seeds great difficulty is experienced in securing a fine state
+of subdivision suited to complete extraction. In such cases it is
+advisable to conduct the process in two stages. In the first stage
+the material, in coarse powder, is exhausted as far as possible and
+the percentage of oil determined. The residue is then easily reduced
+to a fine powder, in an aliquot part of which the remaining oil is
+determined in the usual way.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_79" src="images/fig79.jpg" alt="" width="400" height="484" >
+    <p class="center spb1">Fig. 79.—Oil Press.</p>
+</div>
+
+<p>In securing oils for physical and chemical examination both pressure
+and solution may be employed. The purest oils are secured by pressure
+at a low temperature. To obtain anything like a good extraction some
+sort of hydraulic pressure must be used. In this laboratory a press is
+employed in which the first pressure is secured by a screw and this is
+<span class="pagenum"><a id="Page_313"></a>[Pg 313]</span>
+supplemented by hydraulic pressure in which glycerol is the
+transmitting liquid. The construction of the press is shown in the
+accompanying <a href="#FIG_79">figure</a>.</p>
+
+<p>The whole press is warmed to nearly 100°. The hot finely ground oily
+material, enclosed in a cloth bag, is placed in the perforated cylinder
+and compressed as firmly as possible by turning with the hands the
+wheel shown at the top of the <a href="#FIG_79">figure</a>. The final
+pressure is secured by the screw shown at the bottom of the figure
+whereby a piston is driven into a cylinder containing glycerol. The
+degree of pressure obtained is equal to 300 atmospheres.</p>
+
+<p>Even with the best laboratory hydraulic pressure not more than
+two-thirds of the total oil contents of oleaginous seeds can be secured
+and the process is totally inapplicable to securing the oil from
+tissues when it exists in quantities of less than ten per cent. To get
+practically all of the oil the best method is to extract with carefully
+distilled petroleum of low boiling point.</p>
+
+<p>In the preparation of this reagent the petroleum ether of commerce,
+containing bodies boiling at temperatures of from 35° to 80°, is
+repeatedly fractioned by distillation until a product is obtained
+which boils at from 45° to 60°. The distillation of this material
+is conducted in a large flask heated with steam, furnished with a
+column containing a number of separatory funnels and connected with an
+appropriate condenser. The distillate is secured in a bottle packed
+with broken ice, as shown in <a href="#FIG_80">Fig. 80</a>. A thermometer
+suspended in the vapor of the petroleum serves to regulate the process. Too
+much care to avoid accidents cannot be exercised in this operation. Not only
+must steam be used in heating, but all flame and fire must be rigidly
+excluded from the room in which the distillation takes place, and
+the doors leading to other rooms where gas jets may be burning must
+be kept closed. In the beginning of the process, as much as possible
+of the petroleum boiling under 45° must be removed and rejected. The
+distillation is then continued until the temperature rises above 60°.
+The parts of the distillate saved between these temperatures are
+redistilled under similar conditions. Other portions of the petroleum,
+boiling at other temperatures, may be secured in the same way. The
+<span class="pagenum"><a id="Page_314"></a>[Pg 314]</span>
+products may be in a measure freed of unpleasant odors by redistilling
+them from a mixture with lard. When used for quantitive purposes the
+petroleum ether must leave no residue when evaporated at 100°.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_80" src="images/fig80.jpg" alt="" width="400" height="453" >
+    <p class="center spb1">Fig. 80.—Apparatus for Fractional Distillation<br> of Petroleum Ether.</p>
+</div>
+
+<p><b>281. Freeing Extracted Oils from Petroleum.</b>—The petroleum ether
+which is used for extracting oils tends to give them an unpleasant odor
+and flavor and its entire separation is a matter of some difficulty.
+The greater part of the solvent may be recovered as described in
+paragraph <b><a href="#P_43">43</a></b>. Heating the extracted oil for several hours in
+thin layers, will remove the last traces of the solvent, but affords
+<span class="pagenum"><a id="Page_315"></a>[Pg 315]</span>
+opportunity for oxidation, especially in the case of drying oils. An
+effective means of driving off the last traces of petroleum is to cause
+a current of dry carbon dioxid to pass through the sample contained
+in a cylinder and heated to a temperature of from 85° to 90°. The
+atmosphere of the inert gas will preserve the oil from oxidation and
+the sample will, as a rule, be found free of the petroleum odor after
+about ten hours treatment. Ethyl ether or chloroform may be used
+instead of petroleum, but these solvents act on other matters than
+the glycerids, and the extract is therefore liable to be contaminated
+with more impurities than when the petroleum ether is employed. Other
+solvents for fats are carbon tetrachlorid, carbon disulfid, and
+benzene. In general, petroleum ether should be employed in preference
+to other solvents, except in the case of castor oil, which is
+difficultly soluble in both petroleum and petroleum ethers.</p>
+
+<p><b>282. Freeing Fats Of Moisture.</b>—Any excess of water in glycerids
+will accumulate at the bottom of the liquid sample and can be removed
+by decanting the fat or separating it from the oil by any other
+convenient method. The warm oil may be almost entirely freed of any
+residual moisture by passing it through a dry filter paper in a jacket
+funnel kept at a high temperature. A section showing the construction
+of such a funnel with a folded filter paper in place, is shown in <a href="#FIG_81">Fig. 81</a>.
+The final drying, when great exactness is required, is accomplished
+in a vacuum, or in an atmosphere of inert gas, or in the cold in an
+exsiccator over sulfuric acid. In drying, it is well to expose the
+hot oil as little as possible to the action of the air. Wherever
+convenient, it should be protected from oxidation by some inert gas or
+a vacuum.</p>
+
+<p id="P_283"><b>283. Sampling for Analysis.</b>—It is a matter of some difficulty
+to secure a representative sample of a fat or oil for analytical
+purposes. The moisture in a fat is apt to be unevenly distributed, and
+the sampling is to be accomplished in a manner to secure the greatest
+possible uniformity. When the quantity of material is of considerable
+quantity a trier may be used which will remove a cylindrical or partly
+cylindrical mass from the whole length or depth. By securing several
+<span class="pagenum"><a id="Page_316"></a>[Pg 316]</span>
+subsamples of this kind, and well mixing them, an average sample of the
+whole mass may be secured. Where the fat is found in different casks
+or packages samples should be drawn from each as described above. The
+subsamples are mixed together in weights corresponding to the different
+casks from which they are taken and the mass obtained by this mixture
+divided into three equal portions. Two of these parts are melted in a
+dish at a temperature not exceeding 60°, with constant stirring, and
+when fully liquid the third part is added. As a rule, the liquid fat
+retains enough heat to melt the added quantity. As soon as the mixed
+fats begin to grow pasty the mass is vigorously stirred to secure an
+intimate mixture of the water and other foreign bodies.<a id="FNanchor_232" href="#Footnote_232" class="fnanchor">[232]</a></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_81" src="images/fig81.jpg" alt="" width="500" height="435" >
+    <p class="center spb1">Fig. 81.—Section Showing Construction of a Funnel<br> for Hot Filtration.</p>
+</div>
+
+<p>In the case of butter fat the official chemists recommend that
+subsamples be drawn from all parts of the package until about 500 grams
+are secured. The portions thus drawn are to be perfectly melted in a
+<span class="pagenum"><a id="Page_317"></a>[Pg 317]</span>
+closed vessel at as low a temperature as possible, and when melted
+the whole is to be shaken violently for some minutes till the mass is
+homogeneous, and sufficiently solidified to prevent the separation of
+the water and fat. A portion is then poured into the vessel from which
+it is to be weighed for analysis, and this should nearly or quite fill
+it. This sample should be kept in a cold place till analyzed.<a id="FNanchor_233" href="#Footnote_233" class="fnanchor">[233]</a></p>
+
+<p><b>284. Estimation of Water.</b>—In the official method for butter
+fat, which may be applied to all kinds, about two grams are dried to
+constant weight, at the temperature of boiling water, in a dish with
+flat bottom, having a surface of at least twenty square centimeters.</p>
+
+<p>The use of clean dry sand or asbestos is admissible, and is necessary
+if a dish with round bottom be employed.</p>
+
+<p>In the method recommended by Benedikt, about five grams of the sampled
+fat are placed in a small flask or beaker and dried at 100° with
+occasional stirring to bring the water to the surface.</p>
+
+<p>According to the method of Sonnenschein, the sample is placed in a
+flask carrying a cork, with an arrangement of glass tubes, whereby a
+current of dry air may be aspirated over the fat during the process
+of drying. When the flask is properly fitted its weight is taken, the
+fat put in and reweighed to get the exact amount. The fat is better
+preserved by aspirating carbon dioxid instead of air.<a id="FNanchor_234" href="#Footnote_234" class="fnanchor">[234]</a>
+The moisture may also be readily determined by drying on pumice stone,
+as described in paragraph <b><a href="#P_26">26</a></b>. In this case it is well to conduct
+the desiccation in vacuum or in an inert atmosphere to prevent oxidation.</p>
+
+<h3>PHYSICAL PROPERTIES OF FATS.</h3>
+
+<p id="P_285"><b>285. Specific Gravity.</b>—The specific gravity of an oil is
+readily determined by a westphal balance (<b><a href="#P_53">53</a></b>), by a spindle,
+by a sprengel tube, or more accurately by a pyknometer. The general
+principles governing the conduct of the work have already been given
+(<b><a href="#P_48">48-59</a></b>). The methods described for determining the density of
+sugar solutions are essentially the same as those used for oils, but it
+is to be remembered that oils and fats are lighter than water and the
+<span class="pagenum"><a id="Page_318"></a>[Pg 318]</span>
+graduation of the sinkers for the hydrostatic balance, and the
+spindles for direct determination must be for such lighter liquids.
+The necessity of determining the density of a fat at a temperature
+above its melting point is manifest, and for this reason the use of
+the pyknometer at a high temperature (40° to 100°) is to be preferred
+to all the other processes, in the case of fats which are solid at
+temperatures below 25°.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_82" src="images/fig82.jpg" alt="" width="500" height="524" >
+    <p class="center spb1">Fig. 82.—Balance and Westphal Sinker.</p>
+</div>
+
+<p>When great delicacy of manipulation is desired, combined with
+rapid work, an analytical balance and westphal sinker may be used
+conjointly.<a id="FNanchor_235" href="#Footnote_235" class="fnanchor">[235]</a>
+In this case it is well to have two or three sinkers graduated for
+20°, 25°, and 40°, respectively. Nearly all fats, when melted and
+cooled to 40°, remain in a liquid state long enough to determine their
+density. The sinkers are provided with delicate thermometers, and the
+temperature, which at the beginning is a little above the degree at
+which the sinker is graduated, is allowed to fall to just that degree,
+when the equilibrium is secured in the usual manner. The sinker is
+<span class="pagenum"><a id="Page_319"></a>[Pg 319]</span>
+conveniently made to displace just five grams of distilled water at the
+temperature of graduation, but it is evident that a round number is not
+necessary, but only convenient for calculation.</p>
+
+<p><b>286. Expression of Specific Gravity.</b>—Much confusion arises
+in the study of data of densities because the temperatures at which
+the determinations are made are not expressed. The absolute specific
+gravity would be a comparison of the weight of the object at 4°, with
+water at the same temperature. It is evident that such determinations
+are not always convenient, and for this reason the determinations of
+density are usually made at other temperatures.</p>
+
+<p>In the case of a sinker, which at 35° displaces exactly five grams of
+water, the following statements may be made: One cubic centimeter of
+water at 35° weighs 0.994098 gram. The volume of a sinker displacing
+five grams of water at that temperature is therefore 5.0297 cubic
+centimeters. This volume of water at 4° weighs 5.0297 grams. In a given
+case the sinker placed in an oil at 35° is found to displace a weight
+equal to 4.5725 grams corresponding to a specific gravity of 35°/35°
+= 0.9145. From the foregoing data the following tabular summary is
+constructed:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Weight</td>
+      <td class="tdl_wsp">of</td>
+      <td class="tdl_wsp">5.0287</td>
+      <td class="tdl_wsp">cubic</td>
+      <td class="tdl_wsp">centimeters</td>
+      <td class="tdl_wsp">of</td>
+      <td class="tdl_wsp">oil</td>
+      <td class="tdl_wsp">at 35°,</td>
+      <td class="tdl_wsp">4.5725</td>
+      <td class="tdl_wsp">grams.</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">5.0297</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">water</td>
+      <td class="tdl_wsp">at 35°,</td>
+      <td class="tdl_wsp">5.0000</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">5.0297</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">&nbsp;” &nbsp; 4°,</td>
+      <td class="tdl_wsp">5.0297</td>
+      <td class="tdc">”</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Relative</td>
+      <td class="tdl_wsp">weight</td>
+      <td class="tdl_wsp">of</td>
+      <td class="tdl_wsp">oil</td>
+      <td class="tdl_wsp">at</td>
+      <td class="tdl_wsp">35°,</td>
+      <td class="tdl_wsp">to</td>
+      <td class="tdl_wsp">water</td>
+      <td class="tdl_wsp">at</td>
+      <td class="tdl_wsp">35°,</td>
+      <td class="tdl_wsp">0.9145</td>
+      <td class="tdl_wsp">grams.</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">35°,</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">&#8199;4°,</td>
+      <td class="tdl_wsp">0.9092</td>
+      <td class="tdc">”</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>287. Coefficient of Expansion of Oils.</b>—Oils and fats of every
+kind have almost the same coefficient of expansion with increasing
+temperature. The coefficient of expansion is usually calculated by the
+formula</p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">δ = &nbsp;</td>
+      <td class="tdc bb"><i>D</i>₀ - <i>D</i>₀ʹ</td>
+   </tr><tr>
+      <td class="tdc">(<i>tʹ</i> - <i>t</i>)<i>D</i>₀</td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="no-indent">in which δ represents the coefficient of
+expansion, <i>D</i>₀ the density at the lowest temperature, <i>D</i>₀ʹ
+the density at the highest temperature, <i>t</i> the lowest, and
+<i>tʹ</i> the highest temperatures.</p>
+
+<p>In the investigations made by Crampton it was shown that the formula
+would be more accurate, written as follows:<a id="FNanchor_236" href="#Footnote_236" class="fnanchor">[236]</a></p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl" rowspan="3">δ = &nbsp;<br>&nbsp;</td>
+      <td class="tdc bb"><i>D</i>₀ - <i>D</i>₀ʹ</td>
+   </tr><tr>
+      <td class="tdc_top">(<i>tʹ</i> - <i>t</i>) × <span class="u"><i>D</i>₀ + <i>D</i>₀ʹ</span></td>
+   </tr><tr>
+      <td class="tdl_ws2"><span class="ws2">&nbsp; 2</span></td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_320"></a>[Pg 320]</span>
+The absolute densities can be calculated from the formula Δ = δ +
+<i>K</i>, in which Δ represents the coefficient of absolute expansion,
+δ the apparent coefficient of expansions observed in glass vessels, and
+<i>K</i> the cubical coefficient of expansion of the glass vessel. The
+mean absolute coefficient of expansion for fats and oils, for 1° as
+determined by experiment, is almost exactly 0.0008, and the apparent
+coefficient of expansion nearly 0.00077.<a id="FNanchor_237" href="#Footnote_237" class="fnanchor">[237]</a></p>
+
+<p><b>288. Standard of Comparison.</b>—In expressing specific gravities
+it is advisable to refer them always to water at 4°. The temperature at
+which the observation is made should also be given. Thus the expression
+of the specific gravity of lard, determined at different temperatures,
+is made as follows:</p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl_ws1" colspan="2">15°.5</td>
+   </tr><tr>
+      <td class="tdl"><i>d</i> —— = &nbsp;</td>
+      <td class="tdc">0.89679;</td>
+   </tr><tr>
+      <td class="tdl_ws1" colspan="2"> &nbsp; 4°</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl_ws1" colspan="2">40°</td>
+   </tr><tr>
+      <td class="tdl"><i>d</i> —— = &nbsp;</td>
+      <td class="tdc">0.91181;</td>
+   </tr><tr>
+      <td class="tdl_ws1" colspan="2"> &nbsp; 4°</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl_ws1" colspan="2">100°</td>
+   </tr><tr>
+      <td class="tdl">and <i>d</i> —— = &nbsp;</td>
+      <td class="tdc">0.85997,</td>
+   </tr><tr>
+      <td class="tdl_ws1" colspan="2"> &nbsp; 4°</td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="no-indent">indicating the relative weights of the sample under examination at
+15°.5, 40°, and 100°, respectively, to water at 4°.</p>
+
+<p><b>289. Densities of Common Fats and Oils.</b>—It is convenient to
+have at hand some of the data representing the densities of common fats
+and oils, and the following numbers are from results of determinations
+made in this laboratory:<a id="FNanchor_238" href="#Footnote_238" class="fnanchor">[238]</a></p>
+
+<table class="spb1">
+   <thead><tr class="fs_90">
+      <th class="tdr" colspan="3">15°.5</th>
+      <th class="tdr" colspan="2">40°</th>
+      <th class="tdr" colspan="2">100°</th>
+   </tr><tr>
+      <th class="tdc">Temperature.</th>
+      <th class="tdc"><i>d</i> =</th>
+      <th class="tdc">&#8212;.</th>
+      <th class="tdc">&nbsp; <i>d</i> =</th>
+      <th class="tdc">&#8212;.</th>
+      <th class="tdc">&nbsp; <i>d</i> =</th>
+      <th class="tdc">&#8212;.</th>
+   </tr><tr class="fs_90">
+      <th class="tdr" colspan="3">4° &#8199;</th>
+      <th class="tdr" colspan="2">4° &#8199;</th>
+      <th class="tdr" colspan="2">4° &#8199;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Leaf lard</td>
+      <td class="tdr_wsp" colspan="2">0.91181</td>
+      <td class="tdr_wsp" colspan="2">0.89679</td>
+      <td class="tdr_wsp" colspan="2">0.85997</td>
+   </tr><tr>
+      <td class="tdl">Lard stearin</td>
+      <td class="tdr_wsp" colspan="2">0.90965</td>
+      <td class="tdr_wsp" colspan="2">&nbsp; 0.89443</td>
+      <td class="tdr_wsp" colspan="2">&nbsp; 0.85750</td>
+   </tr><tr>
+      <td class="tdl">Oleostearin</td>
+      <td class="tdr_wsp" colspan="2">0.90714</td>
+      <td class="tdr_wsp" colspan="2">0.89223</td>
+      <td class="tdr_wsp" colspan="2">0.85572</td>
+   </tr><tr>
+      <td class="tdl">Crude cottonseed oil&emsp;&nbsp;</td>
+      <td class="tdr_wsp" colspan="2">0.92016</td>
+      <td class="tdr_wsp" colspan="2">0.90486</td>
+      <td class="tdr_wsp" colspan="2">0.86739</td>
+   </tr><tr>
+      <td class="tdl">Summer&nbsp;&emsp;”<span class="ws2">&nbsp; ”</span></td>
+      <td class="tdr_wsp" colspan="2">0.92055</td>
+      <td class="tdr_wsp" colspan="2">0.90496</td>
+      <td class="tdr_wsp" colspan="2">0.86681</td>
+   </tr><tr>
+      <td class="tdl">Winter&nbsp;&emsp;&nbsp; ”<span class="ws2">&nbsp; ”</span></td>
+      <td class="tdr_wsp" colspan="2">0.92179</td>
+      <td class="tdr_wsp" colspan="2">0.90612</td>
+      <td class="tdr_wsp" colspan="2">0.86774</td>
+   </tr><tr>
+      <td class="tdl">Refined&nbsp;&emsp;”<span class="ws2">&nbsp; ”</span></td>
+      <td class="tdr_wsp" colspan="2">0.92150</td>
+      <td class="tdr_wsp" colspan="2">0.90573</td>
+      <td class="tdr_wsp" colspan="2">0.86714</td>
+   </tr><tr>
+      <td class="tdl">Compound lard&emsp;”</td>
+      <td class="tdr_wsp" colspan="2">0.91515</td>
+      <td class="tdr_wsp" colspan="2">0.90000</td>
+      <td class="tdr_wsp" colspan="2">0.86289</td>
+   </tr><tr>
+      <td class="tdl">Olive oil</td>
+      <td class="tdr_wsp" colspan="2">0.91505</td>
+      <td class="tdr_wsp" colspan="2">0.89965</td>
+      <td class="tdr_wsp" colspan="2">0.86168</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>290. Melting Point.</b>—The temperature at which fats become
+sensibly liquid is a physical characteristic of some importance.
+Unfortunately, the line of demarcation between the solid and liquid
+states of this class of bodies is not very clear. Few of them pass
+<i>per saltum</i> from one state to the other. In most cases there is
+a gradual transition, which, between its initial and final points, may
+show a difference of several degrees in temperature. It has been noted,
+<span class="pagenum"><a id="Page_321"></a>[Pg 321]</span>
+further, that fats recently melted behave differently from those which
+have been solid for several hours. For this reason it is advisable, in
+preparing glycerids for the determination of their melting point, to
+fuse them the day before the examination is to be made. The temperature
+at which a glycerid passes from a liquid to a solid state is usually
+higher than that at which it resumes its solid form. If, however, the
+change of temperature could be made with extreme slowness, exposing
+the sample for many hours at near its critical temperature, these
+differences would be much less marked.</p>
+
+<p>Many methods have been devised for determining the melting point of
+fats, and none has been found that is satisfactory in every respect. In
+some cases the moment at which fluidity occurs is assumed to be that
+one when the small sample loses its opalescence and becomes clear.
+In other cases the moment of fluidity is determined by the change of
+shape of the sample or by observing the common phenomena presented by
+a liquid body. In still other cases, the point at which the sample
+becomes fluid is determined by the automatic completion of an electric
+circuit, which is indicated by the ringing of a bell. This latter
+process has been found very misleading in our experience. Only a few of
+the proposed methods seem to demand attention here, and some of those,
+depending on the visible liquefaction of a small quantity of the fat or
+based on the physical property, possessed by all liquids when removed
+from external stress, of assuming a spheroidal state will be described.
+Other methods which may demand attention in any particular case may be
+found in the works cited.<a id="FNanchor_239" href="#Footnote_239" class="fnanchor">[239]</a></p>
+
+<p><b>291. Determination in a Capillary Tube.</b>—A capillary tube
+is dipped into the melted fat and when filled one end of the tube
+is sealed in the lamp and it is then put aside in a cool place for
+twenty-four hours. At the end of this time the tube is tied to the bulb
+of a delicate thermometer the length used or filled with fat being of
+the same length as the thermometer bulb. The thermometer and attached
+fat are placed in water, oil, or other transparent media, and gently
+warmed until the capillary column of fat becomes transparent. At this
+moment the thermometric reading is made and entered as the melting
+<span class="pagenum"><a id="Page_322"></a>[Pg 322]</span>
+point of the fat. In comparative determinations the same length of
+time should be observed in heating, otherwise discordant results
+will be obtained. As in all other methods, the resulting members are
+comparative and not absolute points of fusion, and the data secured by
+two observers on the same sample may not agree, if different methods of
+preparing the fat and different rates of fusion have been employed.</p>
+
+<div class="figleft smcap">
+    <img id="FIG_83" src="images/fig83.jpg" alt="" width="100" height="237" >
+    <p class="center">Fig. 83.—<br>Melting<br> Point<br> Tubes.</p>
+</div>
+
+<p>Several modifications of the method just described are practiced, and
+perhaps with advantage in some cases. In one of these a small particle
+of the fat is solidified in a bulb blown on a small tube, as indicated
+in <a href="#FIG_83">Fig. 83</a>, tube <i>a</i>. The tube, in an
+upright position, is heated in a convenient bath until the particle
+of fat just begins to run assuming soon the position shown in tube
+<i>b</i>. This temperature is determined by a thermometer, whose bulb
+is kept in contact with the part of the observation tube containing
+the fat particle. The rise of temperature is continued until the fat
+collected at the bottom of the bulb is entirely transparent. This is
+called the point of complete fusion.<a id="FNanchor_240" href="#Footnote_240" class="fnanchor">[240]</a></p>
+
+<p>Pohl covers the bulb of a thermometer with a thin film of fat, and the
+instrument is then fixed in a test tube, in such a way as not to touch
+the bottom, and the film of fat warmed by the air-bath until it fuses
+and collects in a droplet at the end of the thermometer bulb.<a id="FNanchor_241" href="#Footnote_241" class="fnanchor">[241]</a></p>
+
+<p>Carr has modified this process by inserting the thermometer in a round
+flask in such a way that the bulb of the thermometer is as nearly
+as possible in the center. By this device the heating through the
+intervening air is more regular and more readily controlled.<a id="FNanchor_242" href="#Footnote_242" class="fnanchor">[242]</a></p>
+
+<p>A particle of fat placed on the surface of clean mercury will melt
+when the mercury is raised to the proper temperature. Where larger
+quantities of the fat are employed, a small shot or pellet of mercury
+may be placed upon the surface and the whole warmed until the metal
+<span class="pagenum"><a id="Page_323"></a>[Pg 323]</span>
+sinks. Of the above noted methods, the analyst will find some form
+of capillary tube or the use of a film of the fat on the bulb of a
+thermometer the most satisfactory.<a id="FNanchor_243" href="#Footnote_243" class="fnanchor">[243]</a></p>
+
+<p>Hehner and Angell have modified the sinking point method by increasing
+the size of the sinker without a corresponding increase in weight.
+This is accomplished by blowing a small pear-shaped float, nearly
+one centimeter in diameter and about two long. The stem of the pear
+is drawn out and broken off, and while the bulb is still warm, the
+open end of the stem is held in mercury, and a small quantity of this
+substance, sufficient in amount to cause the float to sink slowly
+through a melted fat, is introduced into the bulb of the apparatus
+and the stem sealed. The whole bulb should displace about one cubic
+centimeter of liquid and weigh, after filling with mercury, about
+three and four-tenths grams. In conducting the experiment about thirty
+grams of the dry melted fat are placed in a large test tube and cooled
+by immersing the tube in water at a temperature of 15°. The tube
+containing the solidified fat is placed in a bath of cold water and the
+sinker is placed in the center of the surface of the fat. The bath is
+slowly heated until the float disappears. The temperature of the bath
+is read just as the bulb part of the float disappears. The method is
+recommended especially by the authors for butter fat investigations.<a id="FNanchor_244" href="#Footnote_244" class="fnanchor">[244]</a></p>
+
+<p><b>298. Melting Point Determined by the Spheroidal State.</b>—The
+method described by the author, depending on the assumption of the
+spheroidal state of a particle of liquid removed from all external
+stress, has been found quite satisfactory in this laboratory, and has
+been adopted by the official chemists.<a id="FNanchor_245" href="#Footnote_245" class="fnanchor">[245]</a>
+In the preparation of the apparatus there are required:</p>
+
+<p>(<i>a</i>) a piece of ice floating in distilled water that has been
+recently boiled, and (<i>b</i>) a mixture of alcohol and water of the
+same specific gravity as the fat to be examined. This is prepared by
+boiling distilled water and ninety-five per cent alcohol for a few
+minutes to remove the gases which they may hold in solution. While
+still hot, the water is poured into the test tube described below until
+it is nearly half full. The test tube is then nearly filled with the
+hot alcohol, which is carefully poured down the side of the inclined
+tube to avoid too much mixing. If the alcohol is not added until the
+<span class="pagenum"><a id="Page_324"></a>[Pg 324]</span>
+water has cooled, the mixture will contain so many air bubbles as to
+be unfit for use. These bubbles will gather on the disk of fat as the
+temperature rises and finally force it to the top.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_84" src="images/fig84.jpg" alt="" width="300" height="497" >
+    <p class="center spb1">Fig. 84.—Apparatus for the<br> Determination of Melting point.</p>
+</div>
+
+<p>The apparatus for determining the melting point is shown in <a href="#FIG_84">Fig. 84</a>,
+and consists of (<i>a</i>) an accurate thermometer reading
+easily tenths of a degree; (<i>b</i>) a cathetometer for reading the
+thermometer (but this may be done with an eye-glass if held steadily
+and properly adjusted); (<i>c</i>) a thermometer; (<i>d</i>) a tall
+beaker, thirty-five centimeters high and ten in diameter; (<i>e</i>)
+a test tube thirty centimeters long and three and a half in diameter;
+(<i>f</i>) a stand for supporting the apparatus; (<i>g</i>) some method
+of stirring the water in the beaker (for example, a blowing bulb of
+rubber, and a bent glass tube extending to near the bottom of the beaker).</p>
+
+<p>The disks of fat are prepared as follows: The melted and filtered fat
+is allowed to fall from a dropping tube from a height of about twenty
+cubic centimeters on a smooth piece of ice floating in recently boiled
+distilled water. The disks thus formed are from one to one and a half
+centimeters in diameter and weigh about 200 milligrams. By pressing the
+ice under the water the disks are made to float on the surface, whence
+<span class="pagenum"><a id="Page_325"></a>[Pg 325]</span>
+they are easily removed with a steel spatula, which should be cooled in
+the ice water before using. They should be prepared a day or at least a
+few hours before using.</p>
+
+<p>The test tube containing the alcohol and water is placed in a tall
+beaker, containing water and ice, until cold. The disk of fat is then
+dropped into the tube from the spatula, and at once sinks until it
+reaches a part of the tube where the density of the alcohol-water is
+exactly equivalent to its own. Here it remains at rest and free from
+the action of any force save that inherent in its own molecules.</p>
+
+<p>The delicate thermometer is placed in the test tube and lowered until
+the bulb is just above the disk. In order to secure an even temperature
+in all parts of the alcohol mixture in the vicinity of the disk, the
+thermometer is gently moved from time to time in a circularly pendulous
+manner.</p>
+
+<p>The disk having been placed in position, the water in the beaker is
+slowly heated, and kept constantly stirred by means of the blowing
+apparatus already described.</p>
+
+<p>When the temperature of the alcohol-water mixture rises to about
+6° below the melting point, the disk of fat begins to shrivel, and
+gradually rolls up into an irregular mass.</p>
+
+<p>The thermometer is now lowered until the fat particle is even with the
+center of the bulb. The bulb of the thermometer should be small, so as
+to indicate only the temperature of the mixture near the fat. A gentle
+rotatory movement from time to time should be given to the thermometer
+bulb. The rise of temperature should be so regulated that the last
+2° of increment require about ten minutes. The mass of fat gradually
+approaches the form of a sphere, and when it is sensibly so the reading
+of the thermometer is to be made. As soon as the temperature is taken
+the test tube is removed from the bath and placed again in the cooler.
+A second tube, containing alcohol and water, is at once placed in the
+bath. The test tube (ice water having been used as a cooler) is of
+low enough temperature to cool the bath sufficiently. After the first
+determination, which should be only a trial, the temperature of the
+bath should be so regulated as to reach a maximum of about 1°.5 above
+the melting point of the fat under examination.
+<span class="pagenum"><a id="Page_326"></a>[Pg 326]</span></p>
+
+<p>The edge of the disk should not be allowed to touch the sides of the
+tube. This accident rarely happens, but in case it should take place,
+and the disk adhere to the sides of the tube, a new trial should be
+made.</p>
+
+<p>Triplicate determinations should be made, and the second and third
+results should show a near agreement.</p>
+
+<p class="center spa1"><i>Example.</i>—Melting point of sample of butter:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdr">Degrees.</td>
+   </tr><tr>
+      <td class="tdl">First trial</td>
+      <td class="tdc">33.15</td>
+   </tr><tr>
+      <td class="tdl">Second trial<span class="ws3">&nbsp;</span></td>
+      <td class="tdc">33.05</td>
+   </tr><tr>
+      <td class="tdl">Third trial</td>
+      <td class="tdc">33.00</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The fatty acids, being soluble in alcohol, cannot be treated as the
+ordinary glycerids. But even those glycerids which are slightly soluble
+in alcohol may be subjected to the above treatment without fear of
+experiencing any grave disturbance of the fusing points.</p>
+
+<p><b>293. Solidifying Point.</b>—The temperature at which a fat shows
+incipient solidification is usually lower than the point of fusion.
+The same difficulties are encountered in determining the temperature
+of solidification as are presented in observing the true melting
+point. The passage from a transparent liquid to an opaque solid is
+gradual, showing all the phases of turbidity from beginning opalescence
+to complete opacity. The best the analyst can do is to determine,
+as accurately as possible, the temperature at which the more solid
+glycerids of the mixture begin to form definite crystals. This point is
+affected to a marked degree by the element of time. A fat cooled just
+below its melting point will become solid after hours, or days, whereas
+it could be quickly cooled far below that temperature and still be limpid.</p>
+
+<p>The methods of observation are the same for the glycerids and fatty
+acids, and the general process of determination is sufficiently set
+forth in the following description of the method as used in this
+laboratory.<a id="FNanchor_246" href="#Footnote_246" class="fnanchor">[246]</a></p>
+
+<div class="figleft smcap">
+    <img id="FIG_85" src="images/fig85.jpg" alt="" width="200" height="498" >
+    <p class="center">Fig. 85.—Apparatus<br> for Determining<br> Crystallizing Point.</p>
+</div>
+
+<p>The melted fat or fat acid is placed in a test tube contained in a
+large bottle, which serves as a jacket to protect the tube from sudden
+or violent changes of temperature. The efficiency of the jacket may be
+<span class="pagenum"><a id="Page_327"></a>[Pg 327]</span>
+increased by exhausting the air therefrom, as in the apparatus for
+determining the heat of bromination, hereafter described. A very
+delicate thermometer, graduated in tenths of a degree, and having a
+long bulb, is employed. By means of the reading glass, the reading can
+be made in twentieths of a degree. The arrangement of the apparatus
+is shown in <a href="#FIG_85">Fig. 85</a>. The test tube is nearly
+filled with the melted matter. The bottom of the jacket should be
+gently warmed to prevent a too rapid congelation in the bottom of the
+test tube containing the melted fat, and the tube is to be so placed
+as to leave an air space between it and the bottom of the bottle. The
+thermometer is suspended in such a manner as to have the bulb as nearly
+as possible in the center of the melted fat. The thermometer should
+be protected from air currents and should be kept perfectly still. In
+case the congealing point is lower than room temperature the jacket
+may be immersed in a cooling mixture, the temperature of which is only
+slightly below the freezing point of the fatty mass.</p>
+
+<p>When crystals of fat begin to form, the descent of the mercury in the
+stem of the thermometer will become very slow and finally reach a
+minimum, which should be noted. As the crystallization extends inwards
+and approaches the bulb of the thermometer a point will be reached when
+the mercury begins to rise. At this time the partially crystallized
+mass should be vigorously stirred with the thermometer and again left
+<span class="pagenum"><a id="Page_328"></a>[Pg 328]</span>
+at rest in as nearly, the original position as possible. By this
+operation the mercury will be made to rise and its maximum position
+should be noted as the true crystallizing point of the whole mass.
+In comparing different samples, it is important that the elements of
+time in which the first crystallization takes place should be kept, as
+nearly as possible, the same. A unit of one hour in cooling the mixture
+from a temperature just above its point of fusion until the incipient
+crystallization is noticed, is a convenient one for glycerids and for
+fat acids.</p>
+
+<p><b>294. Determination of Refractive Power.</b>—The property of
+refracting light is possessed by fats in different degrees and these
+differences are of great help in analytical work. The examination may
+be made by the simple refractometer of Abbe or Bertrand, or by the more
+elaborate apparatus of Pulfrich.</p>
+
+<p>The comparative refractive power of fats can also be observed by
+means of the oleorefractometer of Amagat-Jean or the differential
+refractometer of Zune.<a id="FNanchor_247" href="#Footnote_247" class="fnanchor">[247]</a></p>
+
+<p>For details of the construction of these apparatus, with a description
+of the optical principles on which they are based, the papers above
+cited may be consulted. In this laboratory the instruments which
+have been employed are three in number, <i>viz.</i>, Abbe’s small
+refractometer, Pulfrich’s refractometer using yellow light, and the
+oleorefractometer of Amagat-Jean. A brief description of the methods
+of manipulating these instruments is all that can be attempted in this
+manual.</p>
+
+<p><b>295. Refractive Index.</b>—Refractive index is an expression
+employed to characterize the measurement of the degree of deflection
+caused in a ray of light in passing from one transparent medium into
+another. It is the quotient of the sine of the angle of the incident,
+divided by the sine of the angle of the refracted ray.</p>
+
+<p>In the case of oils which remain liquid at room temperatures, the
+determinations can be made without the aid of any device to maintain
+liquidity. In the case of fat which becomes solid at ordinary room
+temperatures, the determination must either be made in a room
+artificially warmed or the apparatus must have some device, as in the
+<span class="pagenum"><a id="Page_329"></a>[Pg 329]</span>
+later instruments of Abbe and Pulfrich, and in the apparatus of
+Amagat-Jean, whereby the sample under examination can be maintained
+in a transparent condition. In each case the accuracy of the apparatus
+should be tested by pure water, the refractive index of which at 18°
+is 1.333. The refractive index is either read directly on the scale
+as in Abbe’s instrument, or calculated from the angles measured as in
+Pulfrich’s apparatus.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_86" src="images/fig86.jpg" alt="" width="400" height="487" >
+    <p class="center spb1">Fig. 86.—Abbe’s Refractometer.</p>
+</div>
+
+<p><b>296. Abbe’s Refractometer.</b>—For practical use the small
+instrument invented by Abbe will be found sufficient. The one which has
+been in use for many years in this laboratory is shown in <a href="#FIG_86">Fig. 86</a>.
+The illustration represents the apparatus in the position preliminary to
+reading the index. In preparing the sample of oil for observation the
+instrument is turned on its axis until the prisms between which the
+oil is placed assume a horizontal position, as is seen in <a href="#FIG_87">Fig. 87</a>.
+The movable prism is unfastened and laid aside, the fixed prism covered
+with a rectangular shaped piece of tissue paper on which one or two
+drops of the oil are placed. The movable prism is replaced in such a
+manner as to secure a complete separation of the two prisms by the film
+of oiled tissue paper. A little practice will enable the analyst to
+secure this result.</p>
+
+<p>After the paper disk holding the fat is secured by replacing the upper
+prism, the apparatus is placed in its normal position and the index
+moved until the light directed through the apparatus by the mirror
+shows the field of vision divided into dark and light portions. The
+dispersion apparatus is now turned until the rainbow colors on the part
+between the dark and light fields have disappeared. Before doing this,
+however, the telescope, the eyepiece of the apparatus, is so adjusted
+<span class="pagenum"><a id="Page_330"></a>[Pg 330]</span>
+as to bring the cross lines of the field of vision distinctly into
+focus. The index of the apparatus is now moved back and forth until the
+line of the two fields of vision falls exactly at the intersection of
+the cross lines. The refractive index of the fat under examination is
+then read directly upon the scale by means of a small magnifying glass.
+To check the accuracy of the first reading, the dispersion apparatus
+should be turned through an angle of 180° until the colors have again
+disappeared, and, after adjustment, the scale of the instrument again
+read. These two readings should nearly coincide, and their mean is the
+true reading of the fat under examination.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_87" src="images/fig87.jpg" alt="" width="600" height="408" >
+    <p class="center spb1">Fig. 87.—Charging Position of Refractometer.</p>
+</div>
+
+<p>For butter fats the apparatus should be kept in a warm place, the
+temperature of which does not fall below 30°. For reducing the results
+obtained to a standard temperature, say 25°, the factor 0.000176 may be
+used. As the temperature rises the refractive index falls.</p>
+
+<p class="blockquot"><i>Example.</i>—Refractive index of a butter fat
+determined at 32°.4 = 1.4540, reduced to 25° as follows: 32.4 -25 =
+7.4; 0.000176 × 7.4 = 0.0013; then 1.4540 + 0.0013 = 1.4553.</p>
+
+<p><span class="pagenum"><a id="Page_331"></a>[Pg 331]</span>
+The instrument used should be set with distilled water at 18°, the
+theoretical refractive index of water at that temperature being 1.333.
+In the determination above given, the refractive index of pure water
+measured 1.3300; hence the above numbers should be corrected for theory
+by the addition of 0.0030, making the corrected index of the butter fat
+mentioned at the temperature given, 1.4583.</p>
+
+<p><b>297. Pulfrich’s Refractometer.</b>—For exact scientific
+measurements, Pulfrich’s apparatus has given here entire satisfaction.
+In this instrument a larger quantity of the oil is required than for
+the abbe, and this quantity is held in a cylindrical glass vessel luted
+to the top of the prism. The method of accomplishing this and also an
+illustration of the refraction of the rays of light are shown in <a href="#FIG_88">Fig. 88</a>.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_88" src="images/fig88.jpg" alt="" width="300" height="238" >
+    <p class="center spb1">Fig. 88.—Prism of Pulfrich’s<br> Refractometer.</p>
+</div>
+
+<p>The angle <i>i</i> is measured by a divided circle read with the aid of
+a small telescope. The index of the prism of highly refractive glass
+<i>N</i> is known. The oil is seen at <i>n</i>. The light used is the
+yellow sodium ray (<i>D</i>). From the observed angle the refractive
+index of n is calculated from the formula</p>
+
+<table class="spb1 fs_120">
+   <tbody><tr>
+      <td class="tdl"><i>n</i> = &nbsp;</td>
+      <td class="tdc">√</td>
+      <td class="tdc bt">&nbsp;<i>N</i>² - sin²<i>i</i>.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>For convenience the values of <i>n</i> for all usual values of <i>i</i>
+are computed once for all and arranged for use in tabular form. The
+latest model of Pulfrich’s apparatus, arranged both for liquid and
+solid bodies, and also for spectrometric observation is shown in <a href="#FIG_89">Fig. 89</a>.</p>
+
+<p>When the sodium light is used it is placed behind the apparatus and
+the light is collected and reflected on the refractive prism by the
+lens <i>N</i>. Through <i>H</i> and <i>G</i> is secured the micrometric
+reading of the angle on the scale <i>D</i> by means of the telescopic
+arrangement <i>F E</i>. For regulating the temperature of the oil and
+adjacent parts, a stream of water at any desired temperature is made to
+circulate through <i>L</i> and <i>S</i> in the direction indicated by
+the arrows. The manner in which this is accomplished is shown in the
+cross section of that part of the apparatus as indicated in <a href="#FIG_90">Fig. 90</a>.
+<span class="pagenum"><a id="Page_332"></a>[Pg 332]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_89" src="images/fig89.jpg" alt="" width="300" height="502" >
+    <p class="center spb1">Fig. 89.—Pulfrich’s New Refractometer.</p>
+</div>
+<p><span class="pagenum"><a id="Page_333"></a>[Pg 333]</span></p>
+
+<div class="figcontainer smcap">
+  <div class="figsub">
+   <img id="FIG_90" src="images/fig90.jpg" alt="" width="150" height="392" >
+   <p class="center">Fig. 90.—<br>Heating Apparatus<br>for Pulfrich’s<br>Refractometer.</p>
+  </div>
+  <div id="FIG_91" class="figsub">
+   <img src="images/fig91.jpg" alt="" width="300" height="397" >
+   <p class="center">Fig. 91.—Spectrometer Attachment.</p>
+   </div>
+</div>
+
+<p>For further details of the construction and operation of the apparatus
+the original description may be consulted.<a id="FNanchor_248" href="#Footnote_248" class="fnanchor">[248]</a></p>
+
+<p>In case a spectrometric observation is desired the <i>H</i> ray, for
+instance, is produced by the geissler tube <i>Q</i>, <a href="#FIG_91">Fig. 91</a>.
+The light is concentrated and thrown upon the refractive prism by the lens
+<i>P</i>, the lens <i>N</i>, <a href="#FIG_89">Fig. 89</a>, being removed
+for this purpose.</p>
+
+<p>Tables, for correcting the dispersion and for calculating the indices
+for each angle and fraction thereof, and for corrections peculiar to
+the apparatus, accompany each instrument.</p>
+
+<p><b>298. Refractive Indices of some Common Oils.</b>—The following
+<span class="pagenum"><a id="Page_334"></a>[Pg 334]</span>
+numbers show the refractive indices obtained by Long for some of the
+more common oils. The light used was the yellow ray of the sodium
+flame.<a id="FNanchor_249" href="#Footnote_249" class="fnanchor">[249]</a></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc" colspan="2">Name.</th>
+      <th class="tdc">Temperature.</th>
+      <th class="tdc">&nbsp; Refractive &nbsp;<br>index.</th>
+      <th class="tdc">&nbsp; Calculated<br>for 25°.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl" colspan="2">Olive oil (France)</td>
+      <td class="tdc">26°.6</td>
+      <td class="tdr_wsp">1.4673</td>
+      <td class="tdr_wsp">1.4677</td>
+   </tr><tr>
+      <td class="tdl" colspan="2">&nbsp;&emsp;”&nbsp;&emsp;” (California)</td>
+      <td class="tdc">25°.4</td>
+      <td class="tdr_wsp">1.4677</td>
+      <td class="tdr_wsp">1.4678</td>
+   </tr><tr>
+      <td class="tdl">Cottonseed</td>
+      <td class="tdl_wsp">oil</td>
+      <td class="tdc">24°.8</td>
+      <td class="tdr_wsp">1.4722</td>
+      <td class="tdr_wsp">1.4721</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdl_ws1">”</td>
+      <td class="tdc">26°.3</td>
+      <td class="tdr_wsp">1.4703</td>
+      <td class="tdr_wsp">1.4709</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdl_ws1">”</td>
+      <td class="tdc">25°.3</td>
+      <td class="tdr_wsp">1.4718</td>
+      <td class="tdr_wsp">1.4719</td>
+   </tr><tr>
+      <td class="tdl">Sesamé</td>
+      <td class="tdl_wsp">oil</td>
+      <td class="tdc">24°.8</td>
+      <td class="tdr_wsp">1.4728</td>
+      <td class="tdr_wsp">1.4728</td>
+   </tr><tr>
+      <td class="tdl_ws1">&nbsp; ”</td>
+      <td class="tdl_wsp">”</td>
+      <td class="tdc">26°.8</td>
+      <td class="tdr_wsp">1.4710</td>
+      <td class="tdr_wsp">1.4716</td>
+   </tr><tr>
+      <td class="tdl">Castor</td>
+      <td class="tdl_wsp">”</td>
+      <td class="tdc">25°.4</td>
+      <td class="tdr_wsp">1.4771</td>
+      <td class="tdr_wsp">1.4773</td>
+   </tr><tr>
+      <td class="tdl">Lard</td>
+      <td class="tdl_wsp">”</td>
+      <td class="tdc">27°.3</td>
+      <td class="tdr_wsp">1.4657</td>
+      <td class="tdr_wsp">1.4666</td>
+   </tr><tr>
+      <td class="tdl">Peanut</td>
+      <td class="tdl_wsp">”</td>
+      <td class="tdc">25°.3</td>
+      <td class="tdr_wsp">1.4696</td>
+      <td class="tdr_wsp">1.4696</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>In case of the use of Abbe’s apparatus, in which diffused sunlight
+is the source of the illumination, the numbers obtained cannot be
+compared directly with those just given unless the apparatus be first
+so adjusted as to read with distilled water at 18°, 1.333. In this case
+the reading of the scale gives the index as determined by the yellow
+ray. The numbers obtained with Abbe’s instrument for some common oils
+are given below.<a id="FNanchor_250" href="#Footnote_250" class="fnanchor">[250]</a></p>
+
+<p>In the determinations the instrument was set with water at 18°, reading
+1.3300, and they were corrected by adding 0.0030 in order to compensate
+for the error of the apparatus.</p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc">Material.</th>
+      <th class="tdc">&nbsp; Calculated &nbsp;<br> for 25°.</th>
+      <th class="tdc">Corrected<br> index.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Lard</td>
+      <td class="tdc">1.4620</td>
+      <td class="tdc">1.4650</td>
+   </tr><tr>
+      <td class="tdl">Cotton oil</td>
+      <td class="tdc">1.4674</td>
+      <td class="tdc">1.4704</td>
+   </tr><tr>
+      <td class="tdl">Olive oil stearin</td>
+      <td class="tdc">1.4582</td>
+      <td class="tdc">1.4610</td>
+   </tr><tr>
+      <td class="tdl">Lard stearin</td>
+      <td class="tdc">1.4594</td>
+      <td class="tdc">1.4624</td>
+   </tr>
+ </tbody>
+</table>
+
+<p id="P_299"><b>299. Oleorefractometer.</b>—Instead of measuring the angular value
+of the refractive power of an oil it may be compared with some standard
+on a purely arbitrary scale. Such an apparatus is illustrated by the
+oleorefractometer of Amagat-Jean, or by Zeiss’s butyrorefractometer.</p>
+
+<p>In the first named instrument, <a href="#FIG_92">Fig. 92</a>, the oil to be
+examined is compared directly with another typical oil and the shadow produced
+by the difference in refraction is located on a scale read by a telescope
+and graduated for two different temperatures.<a id="FNanchor_251" href="#Footnote_251" class="fnanchor">[251]</a>
+The internal structure of the apparatus is shown in <a href="#FIG_91">Fig. 93</a>.
+<span class="pagenum"><a id="Page_335"></a>[Pg 335]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_92" src="images/fig92.jpg" alt="" width="400" height="609" >
+    <p class="center spb1">Fig. 92.—Oleorefractometer.</p>
+    <img id="FIG_93" src="images/fig93.jpg" alt="" width="600" height="350" >
+    <p class="center spb1">Fig. 93.—Section Showing Construction of Oleorefractometer.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_336"></a>[Pg 336]</span>
+In the center of the apparatus a metal cylinder, <i>A</i>, is found
+carrying two plate glass pieces, <i>C B</i>, so placed as to form an
+angle of 107°. This cylinder is placed in a larger one, provided with
+two circular glass windows. To these two openings are fixed to the
+right and left, the telescopic attachments, <i>G</i>, <i>V, S, E</i>,
+and the apparatus <i>M, H, Sʹ</i>, <i>Eʹ</i>, for rendering the rays
+of light parallel. The field of vision is divided into two portions,
+light and dark, by a semicircular stop inserted in the collimator,
+and contains the double scale shown in the <a href="#FIG_93">figure</a>
+placed at <i>H</i>. The field of vision is illuminated by a gas or oil lamp
+placed at a convenient distance from the collimator. The inner metallic cylinder
+<i>A</i> is surrounded with an outer one, to which the optical parts
+are attached at <i>D Dʹ</i> by means of plane glass plates. This
+cylinder is in turn contained in the large water cylinder <i>P P</i>,
+carrying a thermometer in the opening shown at the top on the left. The
+manipulation of the apparatus is very simple. The outer cylinder is
+filled with water, at a temperature below 22°, the middle one with the
+typical oil furnished with the instrument, the cover of the apparatus
+carrying the thermometer placed in position and the cup-shaped funnel
+inserted in the cylinder <i>A</i>, which is at first also filled
+with the typical oil. The whole system is next brought slowly to
+the temperature of 22° by means of the lamp shown in <a href="#FIG_92">Fig. 92</a>.
+The telescope is adjusted to bring the scale of the field of vision into
+focus and the line dividing the light and shadow of the field should
+fall exactly on 0°<i>a</i>. If this be not the case the 0° is adjusted
+by screws provided for that purpose until it is in proper position.
+The typical oil is withdrawn from <i>A</i> by the cock <i>R</i>, the
+cylinder washed with a little of the oil to be examined and then filled
+therewith. On again observing the field of vision the line separating
+the shadow from the light will be found moved to the right or left,
+if the oil have an index different from that of the typical oil. The
+position of the dividing line is read on the scale.</p>
+
+<p>For fats the temperature of the apparatus is brought exactly to 45° and
+the scale 0°b is used. In other respects the manipulation for the fats
+is exactly that described for oils. In the use of 0°a, in case the room
+<span class="pagenum"><a id="Page_337"></a>[Pg 337]</span>
+be warmer than 22°, all the liquids employed should be cooled below 22°
+before being placed in the apparatus. It is then only necessary to wait
+until the room temperature warms the system to 22°. In the case of fats
+it is advisable to heat all the liquids to about 50° and allow them to
+cool to 45° instead of heating them to that temperature by means of the
+lamp.</p>
+
+<p>One grave objection to this instrument is found in the absence of the
+proper scientific spirit controlling its manufacture and sale, as
+evidenced by the attempt to preserve the secret of the composition
+of the typical oil and the negligence in testing the scale of the
+instruments which will be pointed out further along.</p>
+
+<p>According to Jean<a id="FNanchor_252" href="#Footnote_252" class="fnanchor">[252]</a>
+the common oils, when purified, give the following readings at 22°:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Peanut</td>
+      <td class="tdl_wsp">oil</td>
+      <td class="tdr_wsp">+3.5</td>
+      <td class="tdc">&nbsp; to &nbsp;</td>
+      <td class="tdr">+6.5</td>
+   </tr><tr>
+      <td class="tdl">Colza</td>
+      <td class="tdc">”</td>
+      <td class="tdr_wsp">+17.5</td>
+      <td class="tdc">”</td>
+      <td class="tdr">+21.0</td>
+   </tr><tr>
+      <td class="tdl">Cotton</td>
+      <td class="tdc">”</td>
+      <td class="tdr_wsp">+18.0</td>
+      <td class="tdc">”</td>
+      <td class="tdr">+18.0</td>
+   </tr><tr>
+      <td class="tdl">Linseed</td>
+      <td class="tdc">”</td>
+      <td class="tdr_wsp">+47.0</td>
+      <td class="tdc">”</td>
+      <td class="tdr">+54.5</td>
+   </tr><tr>
+      <td class="tdl">Lard</td>
+      <td class="tdc">”</td>
+      <td class="tdr_wsp">+5.5</td>
+      <td class="tdc">”</td>
+      <td class="tdr">+5.5</td>
+   </tr><tr>
+      <td class="tdl">Olive</td>
+      <td class="tdc">”</td>
+      <td class="tdr_wsp">+1.5</td>
+      <td class="tdc">”</td>
+      <td class="tdr">0.0</td>
+   </tr><tr>
+      <td class="tdl">Sesamé</td>
+      <td class="tdc">”</td>
+      <td class="tdr_wsp">+17.5</td>
+      <td class="tdc">”</td>
+      <td class="tdr">+19.0</td>
+   </tr><tr>
+      <td class="tdl" colspan="2">Oleomargarin</td>
+
+      <td class="tdr_wsp">&nbsp;&emsp;-15.0</td>
+      <td class="tdc">”</td>
+      <td class="tdr">-15.0</td>
+   </tr><tr>
+      <td class="tdl">Butter</td>
+      <td class="tdl_wsp">fat</td>
+      <td class="tdr_wsp">-30.0</td>
+      <td class="tdc">”</td>
+      <td class="tdr">-30.0</td>
+   </tr><tr>
+      <td class="tdl">Mutton</td>
+      <td class="tdl_wsp">oil</td>
+      <td class="tdr_wsp">0.0</td>
+      <td class="tdc">”</td>
+      <td class="tdr">0.0</td>
+   </tr><tr>
+      <td class="tdl">Fish</td>
+      <td class="tdc">”</td>
+      <td class="tdr_wsp">+38.0</td>
+      <td class="tdc">”</td>
+      <td class="tdr">+38.0</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>In this instrument, therefore, vegetable and fish oils, as a rule, show
+a right hand, and animal fats a left hand deviation.</p>
+
+<p>The oleorefractometer has been extensively used in this laboratory and
+the data obtained thereby have been found useful. We have not found,
+however, the values fixed by Jean to be constant. The numbers for lard
+have varied from -3.0 to -10.0, and other fats have shown almost as
+wide a variation from the values assigned by him.</p>
+
+<p>Jean states that the number for lard, determined by the
+oleorefractometer, is -12, and he gives a definite number for each of
+the common oils and fats. On trying the pure lards of known origin in
+this instrument, I have never yet found one that showed a deviation of
+-12 divisions of the scale; but I have no doubt that there are many
+such lards in existence. The pure normal lards derived from the fat of
+<span class="pagenum"><a id="Page_338"></a>[Pg 338]</span>
+a single animal would naturally show greater variations in their
+chemical and physical properties, than a typical lard derived from
+the mixed fats of a great many animals. In leaf lard, rendered in the
+laboratory, the reading of the oleorefractometer was found to be -10°,
+while with the intestinal lard it was -9°. On the other hand, a lard
+rendered from the fat from the back of the animal showed a reading of
+only -3°, and a typical cottonseed oil a reading of +12°. According
+to the statement of Jean, a lard which gives even as low a refractive
+number as -9, by his instrument, would be adjudged at least one-quarter
+cottonseed oil.</p>
+
+<p>After a thorough trial of the instrument of Jean, I am convinced that
+it is of great diagnostic value, but if used in the arbitrary manner
+indicated by the author it would lead to endless error and confusion.
+In other words, this instrument is of greater value in analyses than
+Abbe’s ordinary refractometer, because it gives a wider expansion in
+the limits of the field of vision, and therefore can be more accurately
+read, but it is far from affording a certain means of discovering
+traces of adulteration with other fats.</p>
+
+<p><b>300. Variations in the Instruments.</b>—In the use of the
+oleorefractometer, attention should be called to the fact that, through
+some negligence in manufacture, the instruments do not give, in all
+instances, the same reading with the same substance. Allen obtained the
+following data with a sample of lard examined in three instruments,
+<i>viz.</i>, 4°.5, 6°, and 11°. Such wide differences in the scales
+of the instruments cannot fail to disparage the value of comparative
+determinations.</p>
+
+<p>The variations in samples of known origin, when read on the same
+instrument, however, will show the range of error to which the
+determinations made with the oleorefractometer are subject. Pearmain
+has tabulated a large number of observations of this kind, covering 240
+samples of oils.<a id="FNanchor_253" href="#Footnote_253" class="fnanchor">[253]</a></p>
+
+<p>Following are the data relating to the most important oils.
+<span class="pagenum"><a id="Page_339"></a>[Pg 339]</span></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc">&nbsp;</th>
+      <th class="tdc"><span class="smcap">At</span> 22°.</th>
+      <th class="tdc">&nbsp;</th>
+      <th class="tdc">&nbsp;</th>
+   </tr><tr>
+      <th class="tdc">Name of oil.</th>
+      <th class="tdc">Highest<br>reading.<br>&nbsp; Degrees. &nbsp;</th>
+      <th class="tdc">Lowest<br>reading.<br>&nbsp; Degrees. &nbsp;</th>
+      <th class="tdc">Mean<br>reading.<br>&nbsp; Degrees. &nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Almond</td>
+      <td class="tdr_ws1">10.5</td>
+      <td class="tdr_ws1">8.0</td>
+      <td class="tdr_ws1">9.5</td>
+   </tr><tr>
+      <td class="tdl">Peanut</td>
+      <td class="tdr_ws1">7.0</td>
+      <td class="tdr_ws1">5.0</td>
+      <td class="tdr_ws1">6.0</td>
+   </tr><tr>
+      <td class="tdl">Castor</td>
+      <td class="tdr_ws1">42.0</td>
+      <td class="tdr_ws1">39.0</td>
+      <td class="tdr_ws1">40.0</td>
+   </tr><tr>
+      <td class="tdl">Codliver</td>
+      <td class="tdr_ws1">46.0</td>
+      <td class="tdr_ws1">40.0</td>
+      <td class="tdr_ws1">44.0</td>
+   </tr><tr>
+      <td class="tdl">Cottonseed (crude)</td>
+      <td class="tdr_ws1">17.0</td>
+      <td class="tdr_ws1">16.0</td>
+      <td class="tdr_ws1">16.5</td>
+   </tr><tr>
+      <td class="tdl"><span class="ws2">”</span><span class="ws2">(refined)</span></td>
+      <td class="tdr_ws1">23.0</td>
+      <td class="tdr_ws1">17.0</td>
+      <td class="tdr_ws1">21.5</td>
+   </tr><tr>
+      <td class="tdl">Lard oil</td>
+      <td class="tdr_ws1">-1.0</td>
+      <td class="tdr_ws1">0.0</td>
+      <td class="tdr_ws1">0.0</td>
+   </tr><tr>
+      <td class="tdl">Linseed (crude)</td>
+      <td class="tdr_ws1">52.0</td>
+      <td class="tdr_ws1">48.0</td>
+      <td class="tdr_ws1">50.0</td>
+   </tr><tr>
+      <td class="tdl"><span class="ws2">”</span>&emsp;(refined)</td>
+      <td class="tdr_ws1">54.0</td>
+      <td class="tdr_ws1">50.0</td>
+      <td class="tdr_ws1">52.5</td>
+   </tr><tr>
+      <td class="tdl">Olive</td>
+      <td class="tdr_ws1">3.5</td>
+      <td class="tdr_ws1">1.0</td>
+      <td class="tdr_ws1">2.0</td>
+   </tr><tr>
+      <td class="tdl">Rape</td>
+      <td class="tdr_ws1">20.0</td>
+      <td class="tdr_ws1">16.0</td>
+      <td class="tdr_ws1">17.5</td>
+   </tr><tr>
+      <td class="tdl">Sesamé</td>
+      <td class="tdr_ws1">17.0</td>
+      <td class="tdr_ws1">13.0</td>
+      <td class="tdr_ws1">15.5</td>
+   </tr><tr>
+      <td class="tdl">Sunflower</td>
+      <td class="tdr_ws1">35.0</td>
+      <td class="tdr_ws1">35.0</td>
+      <td class="tdr_ws1">35.0</td>
+   </tr><tr>
+      <td class="tdl">Tallow oil</td>
+      <td class="tdr_ws1">-5.0</td>
+      <td class="tdr_ws1">-1.0</td>
+      <td class="tdr_ws1">-3.0</td>
+   </tr><tr>
+      <td class="tdl">Oleic acid</td>
+      <td class="tdr_ws1">-33.0</td>
+      <td class="tdr_ws1">-29.0</td>
+      <td class="tdr_ws1">-32.0</td>
+   </tr><tr>
+      <td class="tdl" colspan="4">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdr_ws1"><b><span class="smcap">At</span> 45°.</b></td>
+      <td class="tdr_ws1">&nbsp;</td>
+      <td class="tdr_ws1">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Butter</td>
+      <td class="tdr_ws1">-34.0</td>
+      <td class="tdr_ws1">-25.0</td>
+      <td class="tdr_ws1">-30.0</td>
+   </tr><tr>
+      <td class="tdl">Oleomargarin</td>
+      <td class="tdr_ws1">-18.0</td>
+      <td class="tdr_ws1">-13.0</td>
+      <td class="tdr_ws1">-15.0</td>
+   </tr><tr>
+      <td class="tdl">Lard</td>
+      <td class="tdr_ws1">-14.0</td>
+      <td class="tdr_ws1">-8.0</td>
+      <td class="tdr_ws1">-10.5</td>
+   </tr><tr>
+      <td class="tdl">Tallow</td>
+      <td class="tdr_ws1">-18.0</td>
+      <td class="tdr_ws1">-15.0</td>
+      <td class="tdr_ws1">-16.0</td>
+   </tr><tr>
+      <td class="tdl">Paraffin</td>
+      <td class="tdr_ws1">58.5</td>
+      <td class="tdr_ws1">54.0</td>
+      <td class="tdr_ws1">56.0</td>
+   </tr>
+ </tbody>
+</table>
+
+<div class="figcenter smcap">
+    <img id="FIG_94" src="images/fig94.jpg" alt="" width="400" height="523" >
+    <p class="center spb1">Fig. 94.—Butyrorefractometer.</p>
+</div>
+
+<p id="P_301"><b>301. Butyrorefractometer.</b>—Another instrument graduated on an
+arbitrary scale is the butyrorefractometer of Zeiss. This apparatus,
+which resembles in some respects the instrument of Abbe, differs
+therefrom essentially in dispensing with the revolving prisms of
+Amici, whereby the chromatic fringing due to dispersion is corrected,
+and on having the scale fixed for one substance, in this instance,
+pure butter fat. The form of the instrument is shown in <a href="#FIG_94">Fig. 94</a>.
+The achromatization for the butter fat is secured in the prisms between
+which a film of the fat is placed, as in the Abbe instrument. When
+a fat, differing from that for which the instrument is graduated is
+introduced, the fringes of the dark and light portions of the field
+will not only be colored (difference in dispersion), but the line of
+<span class="pagenum"><a id="Page_340"></a>[Pg 340]</span>
+separation will also be displaced (difference in refractive power). The
+apparatus is therefore used in the differential determination of these
+two properties. It must not be forgotten, however, that butter fats
+differ so much in these properties among themselves as to make possible
+the condemnation of a pure as an adulterated sample.</p>
+
+<p><b>302. Method of Charging the Apparatus.</b>—The prism casing of
+the instrument is opened by turning the pin <i>F</i> to the right and
+pushing the half <i>B</i> of the prism casing aside. The prism and its
+appendages must be cleaned with the greatest care, the best means for this
+purpose being soft clean linen moistened with a little alcohol or ether.</p>
+
+<p>Melt the sample of butter in a spoon and pour it upon a small paper
+filter held between the fingers and apply the first two or three drops
+of clear butter fat so obtained to the surface of the prism contained
+in prism casing <i>B</i>. For this purpose the apparatus should be
+raised with the left hand so as to place the prism surface in a
+horizontal position.</p>
+
+<p>Press <i>B</i> against <i>A</i> and replace <i>F</i> by turning it in
+the opposite direction into its original position; thereby <i>B</i> is
+prevented from falling back and both prism surfaces are kept in close contact.</p>
+
+<p><b>303. Method of Observation.</b>—While looking into the telescope,
+give the mirror <i>J</i> such a position as to render the critical line
+which separates the bright left part of the field from the dark right
+part distinctly visible. It may also be necessary to move or turn the
+instrument about a little. First it will be necessary to ascertain
+whether the space between the prism surfaces be uniformly filled with
+butter, for, if not, the critical line will not be distinct.</p>
+
+<p>By allowing a current of water of constant temperature to flow through
+the apparatus, some time previous to the taking of the reading, the at
+first somewhat hazy critical line approaches in a short time, generally
+after a minute, a fixed position and quickly attains its greatest
+distinctness. When this point has been reached note the appearance of
+the critical line (<i>i. e.</i>, whether colorless or colored and in
+the latter case of what color); also note the position of the critical
+line on the centesimal scale, which admits of the tenth divisions being
+<span class="pagenum"><a id="Page_341"></a>[Pg 341]</span>
+conveniently estimated, and at the same time read the thermometer. By
+making an extended series of successive readings and by employing an
+assistant for melting and preparing the small samples of butter, from
+twenty-five to thirty refractometric butter tests may, after a little
+practice, be made in an hour.</p>
+
+<p>The readings of the refractive indices of a large number of butter
+samples made at 25° are, by means of a table which will be found
+below, directly reduced to scale divisions and yield the following
+equivalents:<a id="FNanchor_254" href="#Footnote_254" class="fnanchor">[254]</a></p>
+
+<table class="spb1 fs_90">
+   <tbody><tr>
+      <td class="tdl">Natural butter</td>
+      <td class="tdl_wsp">(1.4590-1.4620) : 49.5-54.0</td>
+      <td class="tdl_wsp">scale</td>
+      <td class="tdl_wsp">divisions.</td>
+   </tr><tr>
+      <td class="tdl">Margarin</td>
+      <td class="tdl_wsp">(1.4650-1.4700) : 58.6-66.4</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl">Mixtures</td>
+      <td class="tdl_wsp">(1.4620-1.4690) : 54.0-64.8</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Whenever, in the refractometric examination of butter at a temperature
+of 25°, higher values than 54.0 are found for the critical lines these
+samples will, according to Wollny, by chemical analysis, always be
+found to be adulterated; but in all samples in which the value for
+the position of the critical line does not fall below 52.5, chemical
+analysis maybe dispensed with and the samples may be pronounced to be
+pure butter.</p>
+
+<p>In calculating the position of the critical line for other temperatures
+than 25° allow for 1° variation of temperature a mean value of 0.55
+scale division. The following table, which has been compiled in this
+manner, shows the values corresponding to various temperatures, each
+value being the upper limit of scale divisions admissible in pure butter:</p>
+
+<table class="spb1 fs_90">
+   <tbody><tr>
+      <td class="tdc">Temp.</td>  <td class="tdc">&nbsp; Sc. div. &nbsp;</td>
+      <td class="tdc">Temp.</td>  <td class="tdc">&nbsp; Sc. div. &nbsp;</td>
+      <td class="tdc">Temp.</td>  <td class="tdc">&nbsp; Sc. div. &nbsp;</td>
+      <td class="tdc">Temp.</td>  <td class="tdc">&nbsp; Sc. div. &nbsp;</td>
+   </tr><tr>
+      <td class="tdc">45°</td>  <td class="tdc">41.5</td>
+      <td class="tdc">40°</td>  <td class="tdc">44.2</td>
+      <td class="tdc">35°</td>  <td class="tdc">47.0</td>
+      <td class="tdc">30°</td>  <td class="tdc">49.8</td>
+   </tr><tr>
+      <td class="tdc">44°</td>  <td class="tdc">42.0</td>
+      <td class="tdc">39°</td>  <td class="tdc">44.8</td>
+      <td class="tdc">34°</td>  <td class="tdc">47.5</td>
+      <td class="tdc">29°</td>  <td class="tdc">50.3</td>
+   </tr><tr>
+      <td class="tdc">43°</td>  <td class="tdc">42.6</td>
+      <td class="tdc">38°</td>  <td class="tdc">45.3</td>
+      <td class="tdc">33°</td>  <td class="tdc">48.1</td>
+      <td class="tdc">28°</td>  <td class="tdc">50.8</td>
+   </tr><tr>
+      <td class="tdc">42°</td>  <td class="tdc">43.1</td>
+      <td class="tdc">37°</td>  <td class="tdc">45.9</td>
+      <td class="tdc">32°</td>  <td class="tdc">48.6</td>
+      <td class="tdc">27°</td>  <td class="tdc">51.4</td>
+   </tr><tr>
+      <td class="tdc">41°</td>  <td class="tdc">43.7</td>
+      <td class="tdc">36°</td>  <td class="tdc">46.4</td>
+      <td class="tdc">31°</td>  <td class="tdc">49.2</td>
+      <td class="tdc">26°</td>  <td class="tdc">51.9</td>
+   </tr><tr>
+      <td class="tdc">40°</td>  <td class="tdc">44.2</td>
+      <td class="tdc">35°</td>  <td class="tdc">47.0</td>
+      <td class="tdc">30°</td>  <td class="tdc">49.8</td>
+      <td class="tdc">25°</td>  <td class="tdc">52.5</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>If, therefore, at any temperature between 45° and 25° values be found
+for the critical line, which are less than the values corresponding to
+the same temperature according to the table, the sample of butter may
+safely be pronounced to be natural, <i>i. e.</i>, unadulterated butter.
+If the reading show higher numbers for the critical line the sample
+should be reserved for chemical analysis. A special thermometer for use
+in the examination of butter will be described in the section devoted
+to dairy products.
+<span class="pagenum"><a id="Page_342"></a>[Pg 342]</span></p>
+
+<p><b>304. Range of Application of the Butyrorefractometer.</b>—The
+extended range of the ocular scale of the refractometer, <i>n</i> =
+1.42 to 1.49, which embraces the refractive indices of the majority of
+oils and fats, renders the instrument applicable for testing oils and
+fats and also for examining glycerol.</p>
+
+<p>By reference to the subjoined table the scale divisions may be
+transformed into terms of refractive indices. It gives the refractive
+indices for yellow light for every ten divisions of the scale. The
+differential column Δ gives the change of the refractive indices in
+terms of the fourth decimal per scale division. Owing to the accuracy
+with which the readings can be taken (0.1 scale division) the error of the
+value of <i>n</i> rarely exceeds one unit of the fourth decimal of <i>n</i>.</p>
+
+<p class="f120 spa1"><b><span class="smcap">Table of Refractive Indices.</span></b></p>
+
+<table class="spb1 fs_90">
+   <thead><tr>
+      <th class="tdc">Scale div.</th>
+      <th class="tdc">n<span class="fs_80"><sub>D</sub></span>.</th>
+      <th class="tdc fs_120">Δ.</th>
+      <th class="tdc">&nbsp; &nbsp; Scale div.</th>
+      <th class="tdc">n<span class="fs_80"><sub>D</sub></span>.</th>
+      <th class="tdc fs_120">Δ.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">&#8199;0</td>
+      <td class="tdc">1.4220</td>
+      <td class="tdc">8.0</td>
+      <td class="tdc">50</td>
+      <td class="tdc">1.4593</td>
+      <td class="tdc">6.6</td>
+   </tr><tr>
+      <td class="tdc">10</td>
+      <td class="tdc">&nbsp;&emsp;1.4300&emsp;&nbsp;</td>
+      <td class="tdc">7.7</td>
+      <td class="tdc">60</td>
+      <td class="tdc">&nbsp;&emsp;1.4650&emsp;&nbsp;</td>
+      <td class="tdc">6.4</td>
+   </tr><tr>
+      <td class="tdc">20</td>
+      <td class="tdc">1.4377</td>
+      <td class="tdc">7.5</td>
+      <td class="tdc">70</td>
+      <td class="tdc">1.4723</td>
+      <td class="tdc">6.0</td>
+   </tr><tr>
+      <td class="tdc">30</td>
+      <td class="tdc">1.4452</td>
+      <td class="tdc">7.2</td>
+      <td class="tdc">80</td>
+      <td class="tdc">1.4783</td>
+      <td class="tdc">5.7</td>
+   </tr><tr>
+      <td class="tdc">40</td>
+      <td class="tdc">1.4524</td>
+      <td class="tdc">6.9</td>
+      <td class="tdc">90</td>
+      <td class="tdc">1.4840</td>
+      <td class="tdc">5.5</td>
+   </tr><tr>
+      <td class="tdc">50</td>
+      <td class="tdc">1.4593</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">100&#8199;</td>
+      <td class="tdc">1.4895</td>
+      <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The process of observation is precisely the same as that already
+described. In cases, however, where the critical line presents very
+broad fringes (turpentine, linseed oil, etc.) it is advisable to repeat
+the reading with the aid of a sodium flame.</p>
+
+<p><b>305. Viscosity.</b>—An important property of an oil, especially
+when its lubricating qualities are considered, is the measure of
+the friction which the particles exert on other bodies and among
+themselves, in other words, its viscosity. In the measure of this
+property no definite element can be considered, but the analyst must
+be content with comparing the given sample with the properties of some
+other liquid regarded as a standard. The usual method of procedure
+consists in determining the time required for equal volumes of the two
+liquids to pass through an orifice of given dimensions, under identical
+conditions of temperature and pressure. In many instances the viscosity
+of oils is determined by comparing them with water or rape oil, while,
+<span class="pagenum"><a id="Page_343"></a>[Pg 343]</span>
+in other cases, a solution of sugar is employed as the standard of measurement.</p>
+
+<p>In case rape oil be taken as a standard and its viscosity represented
+by 100 the number representing the viscosity of any other oil may be
+found by multiplying the number of seconds required for the outflow of
+fifty cubic centimeters by 100 and dividing by 535. If the specific
+gravity vary from that of rape oil, <i>viz.</i>, 0.915, at 15°, a
+correction must be made by multiplying the result obtained above by the
+specific gravity of the sample and dividing the product by 0.915. If
+<i>n</i> be the observed time of outflow in seconds and <i>s</i> the
+specific gravity the viscosity is expressed as follows:<a id="FNanchor_255" href="#Footnote_255" class="fnanchor">[255]</a></p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>V</i> = &nbsp;</td>
+      <td class="tdc bb"><i>n</i> × 100 × <i>s</i></td>
+     <td class="tdl" rowspan="2">&nbsp; = &nbsp;</td>
+      <td class="tdc bb"><i>n</i> × 100 × <i>s</i></td>
+   </tr><tr>
+      <td class="tdc">535 × 0.195</td>
+      <td class="tdc">489.525</td>
+   </tr>
+ </tbody>
+</table>
+
+<div class="figleft smcap">
+    <img id="FIG_95" src="images/fig95.jpg" alt="" width="200" height="585" >
+    <p class="center">Fig. 95.—<br>Doolittle’s<br> Viscosimeter.</p>
+</div>
+
+<p>It is important that the height of the oil in the cylinders from which
+it is delivered be kept constant, and this is secured by supplying
+additional quantities, on the principle of the mariotte bottle.</p>
+
+<p><b>306. The Torsion Viscosimeter.</b>—In this laboratory the torsion
+viscosimeter, based on the principle described by Babcock is used.
+The instrument employed is the one described by Doolittle.<a id="FNanchor_256" href="#Footnote_256" class="fnanchor">[256]</a>
+The construction of the apparatus is illustrated in <a href="#FIG_95">Fig. 95</a>.</p>
+
+<p>A steel wire is suspended from a firm support and fastened to a stem
+which passes through a graduated horizontal disk, thus permitting the
+accurate measurement of the torsion of the wire. The disk is adjusted
+so that the index point reads exactly <i>0</i>, thus showing that there
+is no torsion in the wire. A brass cylinder seven centimeters long by
+five in diameter, having a slender stem by which to suspend it, is
+<span class="pagenum"><a id="Page_344"></a>[Pg 344]</span>
+immersed in the oil and fastened by a thumbscrew to the lower part of
+the stem of the disk. The oil cup is surrounded by a bath of water or
+high fire-test oil, according to the temperature at which it is desired
+to determine the viscosity. This temperature obtained, while the disk
+is resting on its supports, the wire is twisted 360° by rotating the
+milled head at the top. The disk being released, the cylinder rotates
+in the oil by virtue of the torsion of the wire.</p>
+
+<p>The action now observed is identical with that of the simple pendulum.</p>
+
+<p>If there were no resistance to be overcome, the disk would return to
+0, and the momentum thus acquired would carry it 360° in the opposite
+direction. But the resistance of the oil to the rotation of the
+cylinder causes the revolution to fall short of 360°, and the greater
+the viscosity of the oil the greater will be the resistance, and also
+the retardation. This retardation is found to be a very delicate
+measure of the viscosity of the oil.</p>
+
+<p>This retardation may be read in a number of ways, but the simplest
+is to read directly the number of degrees of retardation between the
+first and second complete arcs covered by the rotating pendulum. For
+example, suppose the wire be twisted 360° and the disk released so that
+rotation begins. In order to obtain an absolute reading to start from,
+which shall be independent of any slight error in adjustment, ignore
+the starting point and make the first reading of the index at the end
+of the first swing. The disk is allowed to complete a vibration and
+the needle is read again at its nearest approach to the first point
+read. The difference in the two readings will measure the retardation
+due to the viscosity of the liquid. In order to eliminate errors
+duplicate determinations are made, the milled head being rotated in an
+opposite direction in the second one. The mean of the two readings will
+represent the true retardation. Each instrument is standardized in a
+solution of pure cane sugar, as proposed by Babcock, and the viscosity,
+in each case, is a number representing the number of grams of sugar in
+100 cubic centimeters, which, at 22°, would produce the retardation noted.</p>
+
+<p>Each instrument is accompanied by a table which contains the necessary
+<span class="pagenum"><a id="Page_345"></a>[Pg 345]</span>
+corrections for it and the number expressing the viscosity,
+corresponding to the different degrees of retardation, as read on the
+index. The following numbers, representing the viscosity of some oils
+as determined by the method of Doolittle, were obtained by Krug.<a id="FNanchor_257" href="#Footnote_257" class="fnanchor">[257]</a></p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Peanut</td>
+      <td class="tdl_wsp">oil</td>
+      <td class="tdr">&nbsp;&emsp;48.50</td>
+   </tr><tr>
+      <td class="tdl">Olive</td>
+      <td class="tdc">”</td>
+      <td class="tdr">53.00</td>
+   </tr><tr>
+      <td class="tdl">Cottonseed</td>
+      <td class="tdc">”</td>
+      <td class="tdr">46.25</td>
+   </tr><tr>
+      <td class="tdl">Linseed</td>
+      <td class="tdc">”</td>
+      <td class="tdr">33.50</td>
+   </tr>
+ </tbody>
+</table>
+
+<p id="P_307"><b>307. Microscopic Appearance.</b>—When fats are allowed to slowly
+crystallize from an ethereal solution they may afford crystalline
+forms, which, when examined with a magnifying glass, yield valuable
+indications of the nature and origin of the substance under
+examination.<a id="FNanchor_258" href="#Footnote_258" class="fnanchor">[258]</a></p>
+
+<p>The method of securing fat crystals for microscopic examination, which
+has been used in this laboratory, is as follows: From two to five
+grams of the fat are placed in a test tube and dissolved in from ten
+to twenty cubic centimeters of ether. The tube is loosely stoppered
+with cotton and allowed to stand, for fifteen hours or longer, in a
+moderately warm room where no sudden changes of temperature are likely
+to take place. It is advisable to prepare several solutions of the same
+substance with varying properties of solvent, for it is not possible
+to secure in a given instance those conditions which produce the most
+characteristic crystals. The rate and time of the crystallization
+should be such that the microscopic examination can take place when
+only a small portion of the fat has separated in a crystalline
+condition. A drop of the mass containing the crystals is removed by
+means of a pipette, placed on a slide, a drop of cotton or olive
+oil added, a cover glass gently pressed down on the mixture and the
+preparation subjected to microscopic examination. Several slides should
+be prepared from the same or different crystallizations. Sometimes the
+results of an examination made in this way are very definite, but the
+analyst must be warned not to expect definite data in all cases. Often
+the microscopic investigations result in the production of negative or
+misleading observations, and, at best, this method of procedure must be
+regarded only as helpful and confirmatory.</p>
+
+<p>A modification of the method of preparation described above has been
+<span class="pagenum"><a id="Page_346"></a>[Pg 346]</span>
+suggested by Gladding.<a id="FNanchor_259" href="#Footnote_259" class="fnanchor">[259]</a>
+About five grams of the melted fat are placed in a small erlenmeyer,
+dissolved in a mixture of ten cubic centimeters of absolute alcohol
+mixed with half that quantity of ether. The flask is stoppered with
+a plug of cotton and allowed to stand in a cool place for about half
+an hour. By this treatment the more easily crystallizable portions of
+the fat separate in a crystalline form, while the triolein and its
+nearly related glycerids remain in solution. The crystalline product is
+separated by filtration through paper wet with alcohol and washed once
+with the solvent mentioned above. After drying in the air for some time
+the crystals are removed from the paper and dissolved in twenty-five
+cubic centimeters of ether, the cotton plug inserted, and the
+erlenmeyer placed, in a standing position, in a large beaker containing
+water. The water jacket prevents any sudden changes of temperature and
+affords an opportunity for the uniform evaporation of the ether which
+should continue for fifteen hours or longer in a cool place.</p>
+
+<p>Other solvents, <i>viz.</i>, alcohol, chloroform, carbon disulfid,
+carbon tetrachlorid, petroleum and petroleum ether have been
+extensively used in the preparation of fat crystals for microscopic
+examination, but in our experience none of these is equal to ether when
+used as already described.</p>
+
+<p id="P_308"><b>308. Microscopic Appearance of Crystals of Fats.</b>—For an
+extended study and illustration of the characteristics of fat crystals
+the bulletin of the Division of Chemistry, already cited, may be
+consulted. In the case of lard, there is a tendency, more or less
+pronounced, to form prismatic crystals with rhombic ends. Beef fat on
+the other hand shows a tendency to form fan-shaped crystals in which
+the radii are often curved.</p>
+
+<p>Typical crystals of swine and beef fat are shown in the accompanying
+figures, <a href="#FIG_96">96</a> and <a href="#FIG_97">97</a>.<a id="FNanchor_260" href="#Footnote_260" class="fnanchor">[260]</a>
+In mixtures of swine and beef fats the typical crystals are not always
+developed, but in most cases the fan-shaped crystals of the beef fat
+will appear more or less modified when that fat forms twenty per cent
+or more of the mixture. When only five or ten per cent of the beef fat
+on the one hand or a like amount of swine fat on the other are present
+the expectation of developing any characteristic crystals of the
+minimum constituent is not likely to be realized.
+<span class="pagenum"><a id="Page_347"></a>[Pg 347]</span></p>
+
+<p>The typical crystals of lard are thought by some experts to be palmitin
+and those of beef fat stearin, but no direct evidence has been adduced
+in support of these <i>a priori</i> theories.</p>
+
+<p>In the experience of this laboratory, as described by Crampton,<a id="FNanchor_261" href="#Footnote_261" class="fnanchor">[261]</a>
+the differences between the typical crystallization of beef and swine
+fats are plainly shown. In mixed fats, on the contrary, confusing
+observations are often made. In a mixture of ten per cent of beef
+and ninety per cent of swine fats a uniform kind of crystallization
+is observed, not distinctly typical, but the characteristics of the
+lard crystals predominate. In many cases a positive identification
+of the crystals is only made possible by repeated crystallizations.
+In the examination of so-called refined lards, which are mixtures of
+lard and beef fat, the form of aggregation of the crystals is found
+to resemble the fan-shaped typical forms of beef fat. When the single
+crystals, however, are examined with a higher magnifying power, they
+are not found to be pointed but blunt, and some present the appearance
+of plates with oblique terminations, but not so characteristic as
+those obtained from pure lard. In other cases in compound lards no
+beef fat crystals are observed and these lards may have been made
+partly of cotton oil stearin. When a lard crystal presents its edge
+to observation it may readily escape identification, or may even be
+mistaken for a crystal of beef fat. In order to insure a side view the
+cover glass should be pressed down with a slight rotatory movement,
+whereby some of the lard crystals at least may be made to present a
+side view.</p>
+
+<p><b>309. Observation of Fat Crystals with Polarized Light.</b>—The
+appearance of fat crystals, when observed by means of polarized light
+alone or with the adjunct of a selenite plate, is often of value in
+distinguishing the nature and origin of the sample.<a id="FNanchor_262" href="#Footnote_262" class="fnanchor">[262]</a></p>
+
+<p>Every fat and oil which is amorphous will present the same set of
+phenomena when observed with polarized light through a selenite plate,
+but when a fat has been melted and allowed to cool slowly the field of
+vision will appear mottled and particolored when thus examined. This
+method has been largely used in the technical examination of butter for
+<span class="pagenum"><a id="Page_348"></a>[Pg 348]</span>
+adulterants, and the microscope is extensively employed by the chemists
+of the Bureau of Internal Revenue for this purpose. In the examination
+of the crystals of butter fat by polarized light a cross is usually
+observed when the nicols are turned at the proper angle, but the cross,
+while almost uniformly seen with butter, is not distinctive, since
+other fats often show it. These forms of crystals are best obtained by
+heating the butter fat to the boiling-point of water for about a minute
+and then allowing it to slowly solidify, and stand for twenty-four hours.</p>
+
+<p>Pure butter, properly made, is never subjected to fusion, and hence,
+when examined through a selenite plate, presents a uniform field of
+vision similarly illuminated and tinted throughout. In oleomargarin,
+the fats are sometimes, during their preparation, in a fused condition.
+The field of vision is therefore filled to a greater or less extent
+with crystals more or less perfect in form. Some of these crystals,
+being doubly refracting, will impart to a selenite field a mottled
+appearance. Such a phenomenon is therefore indicative of a fraudulent
+butter or of one which has been at some time subjected to a temperature
+at or above its fusing point.</p>
+
+<p><b>310. Spectroscopic Examination of Oils.</b>—The presence of
+chlorophyll or of its alteration products is a characteristic of crude
+oils of vegetable origin. In refined oils, even when of a vegetable
+origin, all traces of the chlorophyll products may disappear. The
+absorption bands given by oils are not all alike and in doubtful cases
+a suspected sample should be compared with one of known origin.</p>
+
+<p>In conducting the examination, the oil in a glass vessel with parallel
+sides, is placed in front of the slit of the spectroscope and any
+absorption band is located by means of the common divided scale and by
+the color of the spectrum on which it falls. Olive and linseed oils
+give three sharply defined absorption bands, a very dark one in the
+red, a faint one on the orange and a well marked one in the green.</p>
+
+<p>Sesame, arachis, poppyseed and cottonseed oils also show absorption
+bands. Castor and almond oils do not affect the spectrum.</p>
+
+<div class="figcenter smcap">
+    <p class="f110"><b>Fig. 96.</b></p>
+    <img id="FIG_96" src="images/fig96.jpg" alt="" width="500" height="495" >
+    <p class="center spb1">Lard Crystals × 65.</p>
+    <p class="f110"><b>Fig. 97.</b></p>
+    <img id="FIG_97" src="images/fig97.jpg" alt="" width="500" height="492" >
+    <p class="center">Refined Lard (beef fat) Crystals × 65.</p>
+    <p class="spb2">A. Hoen &amp; Co., Lithocaustic.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_349"></a>[Pg 349]</span>
+Rape and flaxseed oils absorb a part of the spectrum but do not affect
+the rest of it. The spectroscope is of little practical utility in oil
+analysis.<a id="FNanchor_263" href="#Footnote_263" class="fnanchor">[263]</a></p>
+
+<p><b>311. Critical Temperature of Solution.</b>—The study of the
+critical temperature of solution of oils has been made by Crismer,
+who finds it of value in analytical work.<a id="FNanchor_264" href="#Footnote_264" class="fnanchor">[264]</a>
+If a fatty substance be heated under pressure, with a solvent, <i>e.
+g.</i>, alcohol, it will be noticed that as the temperature rises the
+meniscus of separation of the two liquids tends to become a horizontal
+plane. If at this point the contents of the tube be thoroughly mixed
+by shaking and then be left at rest, a point will soon be reached at
+which the two liquids again separate, and this point is distinctly a
+function of temperature. Following is a description of a convenient
+method of determining the critical temperature of the solution of fats
+and oils for experimental purposes. Tubes are prepared for holding the
+reagents in such a way that, after the introduction of the fat and
+alcohol, they can be easily sealed. The capacity of these tubes should
+be about five cubic centimeters. They should be charged with about one
+cubic centimeter of the dry filtered fat and about twice that quantity
+of ninety-five per cent alcohol. Care should be exercised to avoid
+touching the upper sides of the tube with the reagents. When charged
+the tubes are sealed in the flame of a lamp and attached to the bulb of
+a delicate thermometer in such a manner as to have the surface of its
+liquid contents even with the top of the bulb. The tube is conveniently
+fastened to the thermometer by a platinum wire. For duplicate
+determinations two tubes may be fastened to the same thermometric bulb.
+The apparatus thus prepared is placed in a large vessel filled with
+strong sulfuric acid. The operator should be careful to protect himself
+from the danger which might arise from an explosion of the sealed tubes
+during heating. It is advisable in all cases to observe the reaction
+through a large pane of clear glass. The bath of sulfuric acid is
+heated by any convenient means and an even temperature throughout the
+mass is secured by stirring with the thermometer and its attachments.
+When the meniscus which separates the two liquids becomes a horizontal
+plane the thermometer is removed and the liquid in the tubes well mixed
+<span class="pagenum"><a id="Page_350"></a>[Pg 350]</span>
+until it appear homogeneous. The thermometer is replaced in the bath,
+which is allowed to cool slowly, and the phenomena which take place
+in the sealed tubes are carefully noted. The critical temperature
+of solution is that at which the two liquids begin to separate.
+This moment is easily noted. It is, moreover, preceded by a similar
+phenomenon taking place in the capillary part of the tube which retains
+a drop of the mixture on shaking. In this droplet an opalescence
+is first noted. In the mass of the liquid this opalescence, a few
+seconds afterwards, is observed to permeate the whole, followed by the
+formation of zones and finally of the reappearance of the meniscus of
+separation between the two liquids. The temperature at this moment of
+opalescence preceding the separation of the liquid is the critical
+temperature of solution. With alcohol of 0.8195 specific gravity, at
+15°.5 (ninety-five per cent), the observed critical temperatures for
+some of the more common fats and oils are as given below:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl" colspan="2">Butter fat</td>
+      <td class="tdr">100°.0</td>
+   </tr><tr>
+      <td class="tdl" colspan="2">Oleomargarin</td>
+      <td class="tdr">125°.0</td>
+   </tr><tr>
+      <td class="tdl">Peanut</td>
+      <td class="tdl">oil</td>
+      <td class="tdr">123°.0</td>
+   </tr><tr>
+      <td class="tdl">Cotton</td>
+      <td class="tdl_wsp">”</td>
+      <td class="tdr">116°.0</td>
+   </tr><tr>
+      <td class="tdl">Olive</td>
+      <td class="tdl_wsp">”</td>
+      <td class="tdr">123°.0</td>
+   </tr><tr>
+      <td class="tdl">Sesamé</td>
+      <td class="tdl_wsp">”</td>
+      <td class="tdr">121°.0</td>
+   </tr><tr>
+      <td class="tdl">Colza</td>
+      <td class="tdl_wsp">”</td>
+      <td class="tdr">132°.5</td>
+   </tr><tr>
+      <td class="tdl" colspan="2">Mutton tallow</td>
+      <td class="tdr">116°.0</td>
+   </tr><tr>
+      <td class="tdl" colspan="2">Beef marrow</td>
+      <td class="tdr">125°.0</td>
+   </tr><tr>
+      <td class="tdl" colspan="2">Nut oil</td>
+      <td class="tdr"><span class="ws2">&nbsp;</span>100°.5</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>When the alcohol is not pure or if it be of a different density from
+that named, the numbers expressing the critical temperature of solution
+will vary from those given above.</p>
+
+<p><b>312. Polarization.</b>—The pure glycerids are generally neutral to
+polarized light. In oils the degree of polarization obtained is often
+variable, sometimes to the right and sometimes to the left. Olive oil,
+as a rule, shows a slight right hand polarization. Peanut, sesamé, and
+cottonseed oils vary in polarizing power, but in no case is it very
+marked. Castor oil polarizes slightly to the right.</p>
+
+<p>In determining the polarizing power of an oil it should be obtained in
+a perfectly limpid state by filtration and observed through a tube of
+<span class="pagenum"><a id="Page_351"></a>[Pg 351]</span>
+convenient length, as a rule, 200 millimeters. The deviation obtained
+may be expressed in divisions of the sugar scale of the instrument or
+in degrees of angular rotation.</p>
+
+<p><b>313. Turbidity Temperature.</b>—The turbidity temperature of a
+fat, when dissolved in glacial acetic acid, as suggested by Valenta,
+may prove of some diagnostic value.<a id="FNanchor_265" href="#Footnote_265" class="fnanchor">[265]</a>
+The fats are dissolved, with the aid of heat, in glacial acetic acid
+and, on slowly cooling, the temperature at which they become turbid is
+observed. The following data observed by Jones are given for
+comparison.<a id="FNanchor_266" href="#Footnote_266" class="fnanchor">[266]</a></p>
+
+<p>The numbers represent the turbidity temperature of the fat when treated
+with the glacial acetic acid, and allowed to cool slowly. Butter fat,
+from 40° to 70°, mostly from 52° to 65°; oleomargarin, 95° to 106°;
+rape oil, 101°; sesamé oil, 77°; linseed oil, 53° to 57°; lard oil,
+96°; olive oil, 89°; peanut oil, 61° to 88°.</p>
+
+<p>It is important in this test that the acetic acid be absolutely
+glacial. About three cubic centimeters of the glacial acetic acid, and
+three of the fat, should be used.</p>
+
+<h3>CHEMICAL PROPERTIES.</h3>
+
+<p><b>314. Solubility in Alcohol.</b>—As has already been noted, the
+glycerids are freely soluble in ether, chloroform, carbon bisulfid,
+acetone, carbon tetrachlorid, and some other less commonly used
+solvents. Their solubility in absolute alcohol is variable and the
+determination of its degree may often be useful in analytical work.</p>
+
+<p>The method used by Milliau for determining the degree of solubility
+is as follows:<a id="FNanchor_267" href="#Footnote_267" class="fnanchor">[267]</a>
+The fatty matter is deprived of its free acids by shaking for half
+an hour with twice its volume of ninety-five per cent alcohol. After
+standing until the liquids are separated, the oil or fat is drawn off
+and washed three times with distilled water. The sample is deprived
+of water by filtering through a hot jacket filter and a given weight
+of the dry sample is well shaken with twice its weight of absolute
+alcohol. A weighed portion of the alcoholic solution obtained is
+evaporated to remove the alcohol and the weight of the residual fat
+determined. From the data obtained the percentage of solubility is
+<span class="pagenum"><a id="Page_352"></a>[Pg 352]</span>
+calculated. Olive oils, when treated as described above, show a
+solubility of about forty-three parts per thousand of absolute alcohol,
+cotton oil sixty-two parts, sesamé forty-one parts, peanut sixty-six
+parts, colza twenty parts, and flaxseed seventy parts per thousand.</p>
+
+<p><b>315. Coloration Produced by Oxidants.</b>—When oils and fats are
+mixed with oxidizing reagents, such as sulfuric and nitric acids, the
+glycerids are partly decomposed with the production of colors which
+have some analytical significance. The most simple method of applying
+these tests is by the use of a thick porcelain plate provided with
+small cup-shaped depressions for holding the few drops of material
+required. Two or three drops of the oil under examination are placed
+in each of the cups, a like quantity of the oxidizing reagent added,
+and the mixture stirred with a small glass rod. The colors produced
+are carefully noted and the mixture is allowed to remain at room
+temperature for at least twelve hours in order that the final tint may
+be observed. The sulfuric acid used for this reaction should have a
+specific gravity of one and seven-tenths and the nitric acid should
+have the usual commercial strength of the strongest acid. Pure lard,
+when treated with sulfuric acid, as above described, shows but little
+change of color while the vegetable oils mostly turn brown or black. In
+addition to the reagents mentioned many others, including sulfuric and
+nitric acids, sulfuric acid and potassium bichromate, chlorin, ammonia,
+hydrogen peroxid, sodium hydroxid and aqua regia are used. Only a few
+of these tests seem to have sufficient analytical importance to merit
+any detailed description.<a id="FNanchor_268" href="#Footnote_268" class="fnanchor">[268]</a></p>
+
+<p id="P_316"><b>316. Coloration in Large Masses.</b>—Instead of applying the color
+test in the small way just described, larger quantities of the fat may
+be used, either in the natural state or after solution in petroleum
+or other solvent. For this purpose about ten cubic centimeters of
+the oil are shaken with a few drops of sulfuric acid or sulfuric and
+nitric acids. Lard, when thus treated (five drops of sulfuric acid to
+ten cubic centimeters of lard) shows practically no coloration. When
+treated with an equal volume of sulfuric acid and shaken, the lard on
+separating has a brown-red tint.<a id="FNanchor_269" href="#Footnote_269" class="fnanchor">[269]</a></p>
+
+<p><span class="pagenum"><a id="Page_353"></a>[Pg 353]</span>
+Olive oil, with a few drops of sulfuric acid, gives a green color,
+while cottonseed, peanut and other vegetable oils, when thus treated
+with sulfuric and nitric acids, show brown to black coloration. The
+delicacy of the reaction may be increased by first dissolving the fat
+or oil in petroleum ether.</p>
+
+<p>In the use of the coloration test with solvents, a convenient method
+is to dissolve about one cubic centimeter of the fat in a test tube in
+petroleum ether, add one drop of strong sulfuric acid and shake.</p>
+
+<p>In the case of lard, the color does not change or becomes yellow
+or red. Cottonseed oil, similarly treated, shows a brown or black
+color.<a id="FNanchor_270" href="#Footnote_270" class="fnanchor">[270]</a></p>
+
+<p><b>317. Special Nitric Acid Test.</b>—A special nitric acid test for
+cottonseed oil is made with nitric acid of exactly 1.375 specific
+gravity at 15°. This test is especially valuable in detecting
+cottonseed in olive oil. The operation is conveniently conducted by
+shaking together equal volumes of the oil and acid in a test tube until
+an intimate mixture or emulsion is secured. When any considerable
+quantity of cottonseed oil is present an immediate brown coloration
+is produced, from the intensity of which the relative proportion of
+cottonseed oil in the case of a mixture may be roughly approximated.
+When only a little cottonseed oil is present in the mixture, the test
+tube containing the reagents should be set aside for several hours
+before the final observation is made.</p>
+
+<p id="P_318"><b>318. Coloration with Phosphomolybdic Acid.</b>—Among the color
+tests, one which we have found of use is the coloration produced in
+certain oils, mostly of a vegetable origin, by phosphomolybdic
+acid.<a id="FNanchor_271" href="#Footnote_271" class="fnanchor">[271]</a></p>
+
+<p>The method of applying the test is extremely simple. A few cubic
+centimeters of the oil or melted lard are dissolved in an equal volume
+of chloroform, and a third volume of ten per cent phosphomolybdic acid
+added. The mouth of the test tube is closed with the thumb, and the
+whole is violently shaken. On being left in repose, the phosphomolybdic
+acid gathers at the top, and the coloration produced therein is easily
+observed. Cottonseed oil and peanut oil both give a beautiful green when
+<span class="pagenum"><a id="Page_354"></a>[Pg 354]</span>
+treated in this way, which is turned to a blue on the addition of
+ammonia. Linseed oil gives a green color, but forms a kind of emulsion
+which obscures the color to some extent. The pure lards rendered in
+the laboratory give no coloration whatever to the reagent, but it
+retains its beautiful amber color in every case. Mixtures containing
+as little as ten per cent cottonseed oil and ninety per cent lard,
+show a distinct greenish tint, while twenty per cent cottonseed oil
+gives a distinct green. This reaction, therefore, may be considered
+of great value, and on account of its easy application it should come
+into wide use. But it is probable that different samples of cottonseed
+oil, refined to different degrees or in different ways, vary in their
+deportment with phosphomolybdic acid as they do with silver nitrate. In
+other words, there may be some samples of cottonseed oil which will not
+give the green color when treated as above, or so faintly as to have no
+diagnostic value in mixtures.</p>
+
+<p>This reaction shows itself with nearly all vegetable oils but those
+which have been chemically treated either for the purpose of bleaching,
+or for the removal of the acidity, do not respond to the test at all,
+or else in a feeble manner, and that only after standing some time.
+Lard, goose fat, tallow, deer fat, butter fat, etc., show no change in
+color on being treated with this reagent, either with or without the
+addition of alkali. The presence of a small quantity of vegetable oil
+betrays itself by the appearance of the above mentioned coloration,
+the intensity of which forms an approximate measure of the amount of
+vegetable oil present in the sample. In experiments with suspected
+lards, which deviated in their iodin absorption numbers from those of
+genuine lard, the results were concordant, the color deepening as the
+iodin figure rose. The mineral fats (paraffin, vaselin) are without
+action on this reagent, and the only animal fat which reduces it is
+codliver oil.</p>
+
+<p>In like manner some samples of lard may be found which exhibit a
+deportment with this reagent similar to that shown with vegetable oils,
+and tallow and lard oil have been shown to give more distinct reactions
+than some of the vegetable oils.<a id="FNanchor_272" href="#Footnote_272" class="fnanchor">[272]</a></p>
+
+<p>The phosphomolybdic acid may be prepared by precipitating a solution of
+<span class="pagenum"><a id="Page_355"></a>[Pg 355]</span>
+ammonium molybdate with sodium phosphate and dissolving the washed
+precipitate in a warm solution of sodium carbonate. The solution is
+evaporated to dryness and the dry residue subjected to heat. If a blue
+coloration be produced it may be discharged by adding a little nitric
+acid and reheating. The residue is dissolved in water, acidified with
+nitric and made of such a strength as to contain about ten per cent of
+the substance.</p>
+
+<p><b>319. Coloration with Picric Acid.</b>—If to ten cubic centimeters
+of oil a cold saturated solution of picric acid in ether be added and
+the latter be allowed to evaporate slowly, the acid remains dissolved
+in the oil, to which it communicates a brown color.</p>
+
+<p>Pure lard, after the evaporation of the ether, appears of a
+citron-yellow color; if cottonseed oil be present, however, the mixture
+assumes a brown-red color.<a id="FNanchor_273" href="#Footnote_273" class="fnanchor">[273]</a></p>
+
+<p id="P_320"><b>320. Coloration with Silver Nitrate.</b>—A modification of Bechi’s
+method of reducing silver nitrate, given further on, has been proposed
+by Brullé.<a id="FNanchor_274" href="#Footnote_274" class="fnanchor">[274]</a>
+The reagent employed consists of twenty-five parts of silver nitrate
+in 1,000 parts of alcohol of ninety-five per cent strength. Twelve
+cubic centimeters of the oil to be examined and five of the reagent are
+placed in a test tube, held in a vessel containing boiling water, and
+the ebullition continued for about twenty minutes. At the end of this
+time an olive oil, even if it be an impure one, will show a beautiful
+green tint. With seed oils the results are quite different. Cotton oil
+submitted to this treatment becomes completely black. Peanut oil shows
+at first a brown-red coloration and finally a somewhat green tint,
+losing its transparency. Sesamé oil is distinguished by a red-brown
+tint very pronounced and remaining red. Colza oil takes on a yellowish
+green coloration, becomes turbid and is easily distinguished in its
+reaction from olive oil. In mixtures of olive oil with the other oils,
+any notable proportion of the seed oils can be easily determined by the
+above reactions. Natural butter treated with this reagent retains its
+primitive color. That containing margarin becomes a brick-red and as
+little as five per cent of margarin in butter can be detected by this
+test. With ten per cent the tint is very pronounced.
+<span class="pagenum"><a id="Page_356"></a>[Pg 356]</span></p>
+
+<p><b>321. Coloration with Stannic Bromid.</b>—This reagent is prepared
+by adding dry bromin, drop by drop, to powdered or granulated tin
+held in a flask immersed in ice water, until a persistent red color
+indicates that the bromin is in excess. In the application of this
+reagent three or four drops of it are added successively to a little
+less than that quantity of the oil, the mixture well stirred and set
+aside for a few minutes. The unsaponifiable matters of castor oil give
+a green color when thus treated, sandal wood oil a blood-red color and
+cedar oil a purplish color.<a id="FNanchor_275" href="#Footnote_275" class="fnanchor">[275]</a></p>
+
+<p><b>322. Coloration with Auric Chlorid.</b>—The use of auric chlorid
+for producing colorations in oils and fats was first proposed by
+Hirschsohn.<a id="FNanchor_276" href="#Footnote_276" class="fnanchor">[276]</a>
+One gram of auric chlorid is dissolved in 200 cubic centimeters of
+chloroform and about six drops of this reagent added to five cubic
+centimeters of the oil to be tested. In the case of cottonseed oil a
+beautiful red color is produced.</p>
+
+<p>I have found that even pure lards give a trace of color sometimes with
+this reagent, and therefore the production of a slight red tint cannot
+in all cases be regarded as conclusive of the presence of cottonseed
+oil.<a id="FNanchor_277" href="#Footnote_277" class="fnanchor">[277]</a></p>
+
+<p>In general, it may be said that the color reactions with fats and oils
+have a certain qualitive and sorting value, and in any doubtful case
+they should not be omitted. Their value can only be established by
+comparison under identical conditions with a large number of fats and
+oils of known purity. The analyst must not depend too confidingly on
+the data found in books, but must patiently work out these reactions
+for himself.</p>
+
+<p><b>323. Thermal Reactions.</b>—The measurement of the heat produced
+by mixing glycerids with reagents which decompose them or excite other
+speedy chemical reactions, gives valuable analytical data. These
+measurements may be made in any convenient form of calorimeter. The
+containing vessel for the reagents should be made of platinum or some
+other good conducting metal not affected by them.</p>
+
+<p>The heat produced is measured in the usual way by the increment in
+temperature noted in the mass of water surrounding the containing
+<span class="pagenum"><a id="Page_357"></a>[Pg 357]</span>
+vessel. The determination of the heat produced in chemical reactions is
+a tedious and delicate operation requiring special forms of apparatus
+for different substances. The time element in these operations is
+a matter of importance, since it is necessary to work in rooms
+subject to slight changes of temperature and to leave the apparatus
+for some time at rest, in order to bring it and its contents to a
+uniform temperature. For these reasons the more elaborate methods of
+calorimetric examination are not well suited to ordinary analytical
+work, and the reader is referred to standard works on thermal
+chemistry for the details of such operations.<a id="FNanchor_278" href="#Footnote_278" class="fnanchor">[278]</a>
+For our purpose here a description of two simple thermal processes,
+easily and quickly conducted, will be sufficient, while a description
+of the method of determining the heat of combustion of foods will be
+given in another place.</p>
+
+<p><b>324. Heat of Sulfuric Saponification.</b>—Maumené was the first to
+utilize the production of heat caused by mixing sulfuric acid with a
+fat as an analytical process.<a id="FNanchor_279" href="#Footnote_279" class="fnanchor">[279]</a>
+In conducting the process a sulfuric acid of constant strength should
+be employed inasmuch as the rise of temperature produced by a strong
+acid is much greater than when a weaker acid is employed. The process
+is at best only comparative and it is evident that the total rise of
+temperature in any given case depends on the strength of the acid, the
+character, and purity of the fat or oil, the nature of the apparatus
+and its degree of insulation, the method of mixing and the initial
+temperature. For this reason the data given by different analysts vary
+greatly.<a id="FNanchor_280" href="#Footnote_280" class="fnanchor">[280]</a>
+For some of the methods of conducting the operation the reader may
+consult the work of Allen, cited above, or other authorities.<a id="FNanchor_281" href="#Footnote_281" class="fnanchor">[281]</a></p>
+
+<p>In this laboratory the process is conducted as follows:<a id="FNanchor_282" href="#Footnote_282" class="fnanchor">[282]</a>
+The initial temperature of the reagents should be a constant one. For
+oils 20° is a convenient starting point and for fats about 35°, at
+which temperature most of them are soft enough to be easily mixed with
+the reagent. The acid employed should be the pure monohydrated form,
+specific gravity at 20°, 1.845.</p>
+
+<p>The apparatus used is shown in <a href="#FIG_98">Fig. 98</a>.
+<span class="pagenum"><a id="Page_358"></a>[Pg 358]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_98" src="images/fig98.jpg" alt="" width="500" height="467" >
+    <p class="center spb1">Fig. 98.—Apparatus for Determining Rise<br>
+                  of Temperature with Sulfuric Acid.</p>
+</div>
+
+<p>The test tube which holds the reagents is twenty-four centimeters in
+length and five in diameter. It is provided with a stopper having three
+perforations, one for a delicate thermometer, one for a bulb funnel for
+delivering the sulfuric acid, and one to guide a stirring rod bent into
+a spiral as shown. The thermometer is read with a magnifying glass.
+Fifty cubic centimeters of the fat are placed in the test tube and ten
+of sulfuric acid in the funnel and the apparatus is exposed at the
+temperature desired until all parts of it, together with the reagents,
+have reached the same degree. The test tube holding the oil should be
+placed in a vacuum-jacket tube, such as will be described in paragraph
+<b><a href="#P_316">316</a></b>. The oil is allowed to run in as rapidly as possible from
+the funnel and the stirring rod is moved up and down two or three times
+<span class="pagenum"><a id="Page_359"></a>[Pg 359]</span>
+until the oil and acid are well mixed. Care must be exercised to stir
+no more than is necessary for good mixing. The mercury is observed
+as it ascends in the tube of the thermometer and its maximum height
+is noted. With the glass it is easy to read to tenths, when the
+thermometer is graduated in fifths of a degree. When oils are tested
+which produce a rise of temperature approaching 100°, in the above
+circumstances, (cottonseed, linseed and some others) either smaller
+quantities should be used or the oil diluted with some inert substance
+or dissolved in some inert solvent of high boiling point. For a study
+of the variations produced in the rise of temperature when varying
+proportions of oil and acid are used, the work of Munroe may be
+consulted.<a id="FNanchor_283" href="#Footnote_283" class="fnanchor">[283]</a></p>
+
+<p>The thermélaeometer described by Jean is a somewhat complicated piece
+of apparatus and does not possess any advantage over the simple form
+described above.<a id="FNanchor_284" href="#Footnote_284" class="fnanchor">[284]</a></p>
+
+<p>Instead of expressing the data obtained in thermal degrees showing the
+rise of temperature, Thompson and Ballentyne refer them to the heat
+produced in mixing sulfuric acid and water.<a id="FNanchor_285" href="#Footnote_285" class="fnanchor">[285]</a></p>
+
+<p>The observed thermal degree of the oil and acid divided by that of
+the water and acid is termed the specific temperature reaction.
+For convenience in writing, this quotient is multiplied by 100.
+The respective quantities of acid and water are ten and fifty
+cubic centimeters. This method of calculation has the advantage of
+eliminating to a certain degree the variations which arise in the use
+of sulfuric acid of differing specific gravities. In the following
+table are given the comparative data obtained for some common oils.<a id="FNanchor_286" href="#Footnote_286" class="fnanchor">[286]</a></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb">&nbsp;</th>
+      <th class="tdc bb bl bt" colspan="2">Acid of 95.4<br>per cent.</th>
+      <th class="tdc bb bl bt" colspan="2">Acid of 96.8<br>per cent.</th>
+      <th class="tdc bb bl bt br" colspan="2">Acid of 99<br>per cent.</th>
+   </tr><tr>
+      <th class="tdc bb">Kind of oil.</th>
+      <th class="tdc bl bb">Rise of temp.<br>with the oil.</th>
+      <th class="tdc bl bb">Specific temp.<br>reaction.</th>
+      <th class="tdc bl bb">Rise of temp.<br>with the oil.</th>
+      <th class="tdc bl bb">Specific temp.<br>reaction.</th>
+      <th class="tdc bl bb">Rise of temp.<br>with the oil.</th>
+      <th class="tdc bl bb br">Specific temp.<br>reaction.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">0°</td>
+      <td class="tdc">0°</td>
+      <td class="tdc">0°</td>
+      <td class="tdc">0°</td>
+      <td class="tdc">0°</td>
+      <td class="tdc">0°</td>
+   </tr><tr>
+      <td class="tdl">Olive oil</td>
+      <td class="tdc">36.5</td>
+      <td class="tdc">&#8199;95</td>
+      <td class="tdc">39.4</td>
+      <td class="tdc">85</td>
+      <td class="tdc">44.8</td>
+      <td class="tdc">&#8199;96</td>
+   </tr><tr>
+      <td class="tdl">Rapeseed oil</td>
+      <td class="tdc">49.0</td>
+      <td class="tdc">127</td>
+      <td class="tdc">37.0</td>
+      <td class="tdc">89</td>
+      <td class="tdc">58.0</td>
+      <td class="tdc">124</td>
+   </tr><tr>
+      <td class="tdl">Castor oil</td>
+      <td class="tdc">34.0</td>
+      <td class="tdc">&#8199;88</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Linseed oil</td>
+      <td class="tdc">104.5&#8199;</td>
+      <td class="tdc">270</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">125.2&#8199;</td>
+      <td class="tdc">269</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>325. Method of Richmond.</b>—The rise of temperature produced by
+<span class="pagenum"><a id="Page_360"></a>[Pg 360]</span>
+mixing an oil and sulfuric acid is determined by Richmond in a simple
+calorimeter, which is constructed by fitting a small deep beaker inside
+a larger one with a packing of cotton. The heat capacity of the system
+is determined by adding to ten grams of water, in the inner beaker,
+at room temperature, twenty-five grams of water of a noted higher
+temperature and observing the temperature of the mixture. The cooling
+of the system, during the time required for one determination of heat
+of sulfuric saponification, does not exceed one per cent of the whole
+number of calories produced.<a id="FNanchor_287" href="#Footnote_287" class="fnanchor">[287]</a>
+Between the limits of ninety-two per cent and one hundred per cent the
+rise of temperature observed is directly proportional to the strength
+of the acid.</p>
+
+<p><i>Relative Maumené Figure.</i>—The total heat evolved per mean
+molecule is called by Richmond the relative maumené figure. It is
+calculated as follows:</p>
+
+<ul class="index">
+<li class="isub1">Let <i>x</i> = percentage of sulfuric acid in the acid employed;</li>
+<li class="isub2"><i>h</i> = heat capacity of calorimeter in grams of water;</li>
+<li class="isub2"><i>R</i> = observed rise of temperature (twenty-five grams of</li>
+<li class="isub4">oil, five cubic centimeters sulfuric acid);</li>
+<li class="isub2"><i>K</i> = potash absorbed for saponification (19.5 per cent of</li>
+<li class="isub4">potassium hydroxid, standard of comparison);</li>
+<li class="isub2"><i>M</i> = relative maumené figure:</li>
+</ul>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">Then<span class="ws2"><i>M</i></span> = <i>R</i> × &nbsp;</td>
+      <td class="tdc bb">21.5</td>
+      <td class="tdl" rowspan="2">&nbsp; × &nbsp;</td>
+      <td class="tdc bb">20 + <i>h</i></td>
+      <td class="tdl" rowspan="2">&nbsp; × &nbsp;</td>
+      <td class="tdc bb">19.5</td>
+   </tr><tr>
+      <td class="tdc"><i>x</i> - 78.5</td>
+      <td class="tdc">20</td>
+      <td class="tdc"><i>K</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>326. Heat of Bromination.</b>—The rise of temperature caused by
+mixing fats with sulfuric acid has long been used to discriminate
+between different fats and oils. Hehner and Mitchell propose a similar
+reaction based upon the rise of temperature produced by mixing bromin
+with the sample.<a id="FNanchor_288" href="#Footnote_288" class="fnanchor">[288]</a>
+The action of bromin on unsaturated fatty bodies is instantaneous and
+is attended with a considerable evolution of heat. Since the action of
+bromin on many of the oils is very violent it is necessary to dilute
+the reagent with chloroform or glacial acetic acid. Owing to its high
+boiling point the acetic acid has some advantage over chloroform for
+this purpose. The tests are conveniently made in a vacuum-jacket tube.
+<span class="pagenum"><a id="Page_361"></a>[Pg 361]</span>
+In such a tube there is no loss of heat by radiation. The bromin is
+measured in a pipette having at its upper end a tube filled with
+caustic lime held between plugs of asbestos. The bromin sample to be
+tested and the diluent employed are kept at the same temperature before
+beginning the trial. They are quickly mixed and the rise of temperature
+noted. The oil is first dissolved in the chloroform and the bromin then
+added.</p>
+
+<p>A somewhat constant relation is noticed between the rise of temperature
+and the iodin number when one gram of oil, ten cubic centimeters of
+chloroform and one cubic centimeter of bromin are used.</p>
+
+<p>If the rise in temperature in degrees be multiplied by 5.5 the product
+is approximately the iodin number of the sample. Thus a sample of lard
+gave a rise in temperature of 10°.6 and an iodin number of 57.15. The
+number obtained by multiplying 10.6 by 5.5 is 58.3.</p>
+
+<p>In like manner the numbers obtained for some common oils are as follows:</p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc">Material.</th>
+      <th class="tdc">Rise of<br>&nbsp;&emsp;temperature &nbsp;<br> with bromin.</th>
+      <th class="tdc">&nbsp; Iodin No. &nbsp;</th>
+      <th class="tdc">Calculated<br> Iodin No.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Butter fat</td>
+      <td class="tdr_ws1">6.6</td>
+      <td class="tdr_ws1">37.1</td>
+      <td class="tdr_ws1">36.3</td>
+   </tr><tr>
+      <td class="tdl">Olive oil</td>
+      <td class="tdr_ws1">15.0</td>
+      <td class="tdr_ws1">80.8</td>
+      <td class="tdr_ws1">82.5</td>
+   </tr><tr>
+      <td class="tdl">Maize &nbsp;”</td>
+      <td class="tdr_ws1">21.5</td>
+      <td class="tdr_ws1">122.0</td>
+      <td class="tdr_ws1">118.2</td>
+   </tr><tr>
+      <td class="tdl">Cotton ”</td>
+      <td class="tdr_ws1">19.4</td>
+      <td class="tdr_ws1">107.1</td>
+      <td class="tdr_ws1">106.7</td>
+   </tr><tr>
+      <td class="tdl">Castor &nbsp;”</td>
+      <td class="tdr_ws1">15.0</td>
+      <td class="tdr_ws1">83.8</td>
+      <td class="tdr_ws1">82.5</td>
+   </tr><tr>
+      <td class="tdl">Linseed oil</td>
+      <td class="tdr_ws1">30.4</td>
+      <td class="tdr_ws1">160.7</td>
+      <td class="tdr_ws1">167.2</td>
+   </tr><tr>
+      <td class="tdl">Codliver ”</td>
+      <td class="tdr_ws1">28.0</td>
+      <td class="tdr_ws1">144.0</td>
+      <td class="tdr_ws1">140.0</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>327. Modification of the Heat of Bromination Method.</b>—The method
+described above by Hehner and Mitchell presents many grave difficulties
+in manipulation, on account of the inconvenience of handling liquid
+bromin. The process is made practicable by dissolving both the oil or
+fat and the bromin in chloroform, or better in carbon tetrachlorid, in
+which condition the bromin solution is easily handled by means of a
+special pipette.<a id="FNanchor_289" href="#Footnote_289" class="fnanchor">[289]</a></p>
+
+<p>In order to make a number of analyses of the same sample ten grams of
+the fat may be dissolved in chloroform or carbon tetrachlorid and the
+volume completed with the same solvent to fifty cubic centimeters. In
+like manner twenty cubic centimeters of the bromin are dissolved in one
+<span class="pagenum"><a id="Page_362"></a>[Pg 362]</span>
+of the solvents named and the volume completed to 100 cubic centimeters
+therewith.</p>
+
+<p>For convenience of manipulation the solutions are thus made of such a
+strength that five cubic centimeters of each represent one gram of the
+fat and one cubic centimeter of the liquid bromin respectively.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_99" src="images/fig99.jpg" alt="" width="500" height="592" >
+    <p class="center spb1">Fig. 99. Apparatus for Determining Heat of Bromination.</p>
+</div>
+
+<p>The apparatus used for the work is shown in the accompanying <a href="#FIG_99">figure</a>.
+The pipette for handling the bromin solution is so arranged as to be
+<span class="pagenum"><a id="Page_363"></a>[Pg 363]</span>
+filled by the pressure of a rubber bulb, thus avoiding the danger of
+sucking the bromin vapor into the mouth. The filling is secured by
+keeping the bromin solution in a heavy erlenmeyer with a side tubulure
+such as is used for filtering under pressure. The solutions are
+mixed in a long tube, held in a larger vessel, from which the air is
+exhausted to secure a minimum radiation of heat. A delicate thermometer
+graduated in tenths serves to register the rise of temperature. The fat
+solution is first placed in the test tube, with care not to pour it
+down the sides of the tube but to add it by means of a pipette reaching
+nearly to the bottom. The whole apparatus having been allowed to come
+to a standard temperature the bromin solution is allowed to run in
+quickly from the pipette. No stirring is required as the liquids are
+sufficiently mixed by the addition of the bromin solution. The mercury
+in the thermometer rapidly rises and is read at its maximum point by
+means of a magnifying glass. With a thermometer graduated in tenths, it
+is easy to read to twentieths of a degree.</p>
+
+<p>It is evident that the rise of temperature obtained depends on
+similar conditions to those mentioned in connection with sulfuric
+saponification. Each system of apparatus must be carefully calibrated
+under standard conditions and when this is done the comparative rise
+of temperature obtained with various oils and fats will prove of
+great analytical use. It is evident that the ratio of this rise of
+temperature to the iodin number must be determined for every system of
+apparatus and for every method of manipulation employed, and no fixed
+factor can be given that will apply in every case.</p>
+
+<p>With the apparatus above described and with the method of manipulation
+given the following data were obtained for the oils mentioned:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdc">Rise of<br> temperature.</td>
+   </tr><tr>
+      <td class="tdl">Olive oil</td>
+      <td class="tdc">20°.5</td>
+   </tr><tr>
+      <td class="tdl">Refined cottonseed oil&emsp;&nbsp;</td>
+      <td class="tdc">25°.7</td>
+   </tr><tr>
+      <td class="tdl">Sunflowerseed oil</td>
+      <td class="tdc">28°.4</td>
+   </tr><tr>
+      <td class="tdl">Calycanthusseed oil</td>
+      <td class="tdc">29°.0</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Bromin and chloroform, when mixed together, give off heat, due to
+the chemical reaction resulting from the substitution of bromin for
+<span class="pagenum"><a id="Page_364"></a>[Pg 364]</span>
+hydrogen in the chloroform molecule and the formation of hydrobromic
+acid. For this reason the data obtained, when chloroform is used as a
+solvent, are slightly higher than with carbon tetrachlorid. The use of
+the latter reagent is therefore to be preferred.</p>
+
+<p><b>328. Haloid Addition Numbers.</b>—Many of the glycerids possess the
+property of combining directly with the haloids and forming thereby
+compounds in which the haloid, by simple addition, has become a part of
+the molecule. Olein is a type of this class of unsaturated glycerids.
+The process may take place promptly as in the case of bromin or move
+slowly as with iodin. The quantity of the haloid absorbed is best
+determined in the residual matter and not by an examination of the fat
+compound. By reason of the ease with which the amount of free iodin in
+solution can be determined, this substance is the one which is commonly
+employed in analytical operation on fats.</p>
+
+<p>In general, the principle of the operation depends on bringing the fat
+and haloid together in a proper solution and allowing the addition
+to take place by simple contact. The quantity of the haloid in the
+original solution being known, the amount which remains in solution
+after the absorption is complete, deducted from that originally
+present, will give the quantity which has entered into combination with
+the glycerid.</p>
+
+<p><b>329. Hübl’s Process.</b>—In determining the quantity of iodin
+which will combine with a fat, the method first proposed by Hübl,
+or some modification thereof, is universally employed.<a id="FNanchor_290" href="#Footnote_290" class="fnanchor">[290]</a>
+In the determination of the iodin number of a glycerid it is important that
+it be accomplished under set conditions and that iodid be always present
+in large excess. It is only when data are obtained in the way noted
+that they can be regarded as useful for comparison and determination.
+Many modifications of Hübl’s process have been proposed, but it is
+manifestly impracticable to give even a summary of them here. As
+practiced in the chemical laboratory of the Agricultural Department and
+by the Association of Official Agricultural Chemists, it is carried out
+as follows:<a id="FNanchor_291" href="#Footnote_291" class="fnanchor">[291]</a></p>
+
+<h4>(1) <span class="allsmcap">PREPARATION OF REAGENTS.</span></h4>
+
+<p>(<i>a</i>). <i>Iodin Solution.</i>—Dissolve twenty-five grams of pure
+<span class="pagenum"><a id="Page_365"></a>[Pg 365]</span>
+iodin in 500 cubic centimeters of ninety-five per cent alcohol.
+Dissolve thirty grams of mercuric chlorid in 500 cubic centimeters of
+ninety-five per cent alcohol. The latter solution, if necessary, is
+filtered, and then the two solutions mixed. The mixed solution should
+be allowed to stand twelve hours before using.</p>
+
+<p>(<i>b</i>). <i>Decinormal Sodium Thiosulfate Solution.</i>—Dissolve
+24.8 grams of chemically pure sodium thiosulfate, freshly pulverized
+as finely as possible and dried between filter or blotting paper,
+and dilute with water to one liter, at the temperature at which the
+titrations are to be made.</p>
+
+<p>(<i>c</i>). <i>Starch Paste.</i>—One gram of starch is boiled in 200
+cubic centimeters of distilled water for ten minutes and cooled to room
+temperature.</p>
+
+<p>(<i>d</i>). <i>Solution of Potassium Iodid.</i>—One hundred and fifty
+grams of potassium iodid are dissolved in water and the volume made up
+to one liter.</p>
+
+<p>(<i>e</i>). <i>Solution of Potassium Bichromate.</i>—Dissolve 3.874
+grams of chemically pure potassium bichromate in distilled water
+and make the volume up to one liter at the temperature at which the
+titrations are to be made.</p>
+
+<h4>(2). <span class="allsmcap">DETERMINATION.</span></h4>
+
+<p>(<i>a</i>). <i>Standardizing the Sodium Thiosulfate
+Solution.</i>—Place twenty cubic centimeters of the potassium
+bichromate solution, to which have been added ten cubic centimeters of
+the solution of potassium iodid, in a glass stopper flask. Add to this
+mixture five cubic centimeters of strong hydrochloric acid. Allow the
+solution of sodium thiosulfate to flow slowly into the flask until the
+yellow color of the liquid has almost disappeared. Add a few drops of
+the starch paste, and with constant shaking continue to add the sodium
+thiosulfate solution until the blue color just disappears. The number
+of cubic centimeters of thiosulfate solution used multiplied by five is
+equivalent to one gram of iodin.
+<span class="pagenum"><a id="Page_366"></a>[Pg 366]</span></p>
+
+<p class="blockquot"><i>Example.</i>—Twenty cubic centimeters of
+potassium bichromate solution required 16.2 sodium thiosulfate; then
+16.2 × 5 = 81 = number cubic centimeters of thiosulfate solution
+equivalent to one gram of iodin. Then one cubic centimeter thiosulfate
+solution = 0.0124 gram of iodin: (Theory for decinormal solution of
+sodium thiosulfate, one cubic centimeter = 0.0127 gram of iodin.)</p>
+
+<p>(<i>b</i>). <i>Weighing the Sample.</i>—About one gram of butter
+fat is placed in a glass stopper flask, holding about 300 cubic
+centimeters, with the precautions to be mentioned for weighing the fat
+for determining volatile acids.</p>
+
+<p>(<i>c</i>). <i>Absorption of Iodin.</i>—The fat in the flask is
+dissolved in ten cubic centimeters of chloroform. After complete
+solution has taken place thirty cubic centimeters of the iodin solution
+(1) (<i>a</i>) are added. The flask is now placed in a dark place and
+allowed to stand, with occasional shaking, for three hours.</p>
+
+<p>(<i>d</i>). <i>Titration of the Unabsorbed Iodin.</i>—One hundred
+cubic centimeters of distilled water are added to the contents of the
+flask, together with twenty cubic centimeters of the potassium iodid
+solution. Any iodin which may be noticed upon the stopper of the flask
+should be washed back into the flask with the potassium iodid solution.
+The excess of iodin is taken up with the sodium thiosulfate solution,
+which is run in gradually, with constant shaking, until the yellow
+color of the solution has almost disappeared. A few drops of starch
+paste are added, and the titration continued until the blue color
+has entirely disappeared. Toward the end of the reaction the flask
+should be stoppered and violently shaken, so that any iodin remaining
+in solution in the chloroform may be taken up by the potassium iodid
+solution in the water. A sufficient quantity of sodium thiosulfate
+solution should be added to prevent a reappearance of any blue color in
+the flask for five minutes.</p>
+
+<p>(<i>e</i>). <i>Setting the Value of the Iodin Solution by the
+Thiosulfate Solution.</i>—At the time of adding the iodin solution
+to the fat, two flasks of the same size as those used for the
+determination should be employed for conducting the operation described
+above, but without the presence of any fat. In every other respect the
+performance of the blank experiments should be just as described. These
+blank experiments must be made each time the iodin solution is used.</p>
+
+<p><i>Example of Blank Determinations.</i>—Thirty cubic centimeters of
+<span class="pagenum"><a id="Page_367"></a>[Pg 367]</span>
+iodin solution required 46.4 cubic centimeters of sodium thiosulfate
+solution: Thirty cubic centimeters of iodin solution required 46.8
+cubic centimeters of sodium thiosulfate solution: Mean, 46.6 cubic
+centimeters.</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Weight of fat</td>
+      <td class="tdr">1.0479</td>
+      <td class="tdl_wsp">grams</td>
+      <td class="tdl_wsp">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Quantity of iodin solution used</td>
+      <td class="tdr">30.0</td>
+      <td class="tdl_wsp">cubic</td>
+      <td class="tdl_wsp">centimeters</td>
+   </tr><tr>
+      <td class="tdl">Thiosulfate equivalent to iodin used</td>
+      <td class="tdr">46.6</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl">Thiosulfate equivalent to remaining iodin</td>
+      <td class="tdr">14.7</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl">Thiosulfate equivalent to iodin absorbed</td>
+      <td class="tdr">31.9</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl" colspan="4">Percent of iodin absorbed, 31.9 × 0.0124 × 100 ÷ 1.0479 = 37.75.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>330. Character of Chemical Reaction.</b>—The exact nature of
+the chemical process which takes place in this reaction is not
+definitely known. Hübl supposed that the products formed were
+chloro-iodid-additive compounds, and he obtained a greasy product from
+oleic acid, to which he ascribed the formula <b>C₁₈H₃₄IClO₂</b>. By others it
+is thought that chlorin alone may be added to the molecule.<a id="FNanchor_292" href="#Footnote_292" class="fnanchor">[292]</a></p>
+
+<p>In general, it may be said that none of the glycerids capable
+of absorbing halogens is able to take on a quantity equivalent
+to theory.<a id="FNanchor_293" href="#Footnote_293" class="fnanchor">[293]</a>
+While the saturated fatty acids (stearic series) theoretically are not
+able to absorb iodin some of them are found to do so to a small degree.
+It is evident, therefore, that it is not possible to calculate the
+percentage of unsaturated glycerids in a fat from their iodin number
+alone. According to the data worked out by Schweitzer and Lungwitz both
+addition and substitution of iodin take place during the reaction.<a id="FNanchor_294" href="#Footnote_294" class="fnanchor">[294]</a>
+This fact they determined by titration with potassium iodate and iodid
+according to the formula <b>5HI + HIO₃ = 6I + 6H₂O</b>. The authors
+confess that whenever free hydriodic acid is found in the mixture that
+iodin substitution has taken place and that for each atom of hydrogen
+eliminated from the fat molecule two atoms of iodin disappear, one as
+the substitute and the other in the form of hydriodic acid. When carbon
+bisulfid or tetrachlorid is used as a solvent no substitution takes
+place and pure additive compounds are formed.</p>
+
+<p>The following process is recommended to secure a pure iodin addition to
+<span class="pagenum"><a id="Page_368"></a>[Pg 368]</span>
+a glycerid: About one gram or a little less of the oil or fat is placed
+in a glass stopper flask, to which are added about seven-tenths of a
+gram of powdered mercuric chlorid and twenty-five cubic centimeters of
+a solution of iodin in carbon bisulfid. The stopper is made tight by
+smearing it with powdered potassium iodid, tied down, and the mixture
+is heated for some time under pressure. By this method it is found that
+no hydriodic acid is formed, and hence all the iodin which disappears
+is added to the molecule of the glycerid. The additive numbers obtained
+for some oils are appended:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdc bb">Oil.</td>
+      <td class="tdc bb">Time of<br>heating.</td>
+      <td class="tdc bb">Temperature.</td>
+      <td class="tdc bb">Per cent<br>&nbsp; iodin added. &nbsp;</td>
+      <td class="tdc bb">Per cent<br>&nbsp;hübl number.&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Lard oil</td>
+      <td class="tdl_wsp">30 minutes.</td>
+      <td class="tdc">50°.0</td>
+      <td class="tdc">&#8199;73.0</td>
+      <td class="tdc">&#8199;78.4</td>
+   </tr><tr>
+      <td class="tdl">Cottonseed oil &nbsp;</td>
+      <td class="tdl_wsp">2 hours.</td>
+      <td class="tdc">50°.0</td>
+      <td class="tdc">103.0</td>
+      <td class="tdc">106.5</td>
+   </tr><tr>
+      <td class="tdl">Oleic acid</td>
+      <td class="tdl_wsp">2 ”</td>
+      <td class="tdc">65°.5</td>
+      <td class="tdc">&#8199;93.8</td>
+      <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>331. Solution in Carbon Tetrachlorid.</b>—Gantter has called
+attention to the fact that the amount of iodin absorbed by fat does
+not depend alone upon the proportion of iodin present but also upon
+the amount of mercuric chlorid in the solution.<a id="FNanchor_295" href="#Footnote_295" class="fnanchor">[295]</a>
+Increasing amounts of mercuric chlorid cause uniformly a much greater
+absorption of the iodin. For this reason he proposes to discard the use
+of mercuric chlorid altogether for the hübl test and to use a solvent
+which will at the same time dissolve both the iodin and the fat. For
+this purpose he uses carbon tetrachlorid. The solutions are prepared as
+follows:</p>
+
+<p><i>Iodin Solution.</i>—Ten grams of iodin are dissolved in one liter
+of carbon tetrachlorid.</p>
+
+<p>In the preparation of this solution the iodin must not be thrown
+directly into the flask before the addition of the tetrachlorid. Iodin
+dissolves very slowly in carbon tetrachlorid and the solution is made
+by placing it in a sufficiently large weighing glass and adding a
+portion of the carbon tetrachlorid thereto. The solution is facilitated
+by stirring with a glass rod until the added tetrachlorid is apparently
+charged with the dissolved iodin. The dissolved portion is then poured
+into a liter flask, new portions added to the iodin and this process
+continued until the iodin is completely dissolved, and then sufficient
+additional quantities of the tetrachlorid are added to fill the flask
+up to the mark.
+<span class="pagenum"><a id="Page_369"></a>[Pg 369]</span></p>
+
+<p><b>332. Sodium Thiosulfate Solution.</b>—Dissolve 19.528 grams of pure
+sodium thiosulfate in 1000 cubic centimeters of water. For determining
+the strength of the solution by titration, the solution of iodin in
+carbon tetrachlorid and a solution of sodium thiosulfate in water are
+each placed in a burette. A given volume of the iodin solution is
+first run into a flask with a glass stopper and afterward the sodium
+thiosulfate added little by little until, after a vigorous shaking,
+the liquid has only a little color. Some solution of starch is then
+added and shaken until the mixture becomes deep blue. The sodium
+thiosulfate solution is added drop by drop, with vigorous shaking after
+each addition, until the solution is completely decolorized. If both
+solutions have been correctly made with pure materials they will be of
+equal strength; that is, ten cubic centimeters of the iodin solution
+will be exactly decolorized by ten cubic centimeters of the sodium
+thiosulfate solution.</p>
+
+<p><b>333. Method of Conducting the Absorption.</b>—The quantity of the
+fat or oil employed should range from 100 to 200 milligrams, according
+to the absorption equivalent. These quantities should be placed in
+flasks with glass stoppers in the ordinary way. In the flasks are
+placed exactly fifty cubic centimeters of the iodin solution equivalent
+to 500 milligrams of iodin, and the flask is then stoppered and shaken
+until the fat or oil is completely dissolved. In order to avoid the
+volatilization of the iodin finally, sufficient water is poured into
+the flask to form a layer about one millimeter in thickness over the
+solution containing the iodin and fat. The stopper should be carefully
+inserted and the flask allowed to stand at rest for fifty hours.</p>
+
+<p><b>334. Estimation of the Iodin Number.</b>—This is determined in the
+usual way by titration of the amount of iodin left in excess after the
+absorption as above described. The iodin number is to be expressed
+by the number of milligrams of iodin which are absorbed by each 100
+milligrams of fat.</p>
+
+<p><i>Example.</i>—One hundred and one milligrams of flaxseed oil were
+dissolved in fifty cubic centimeters of the carbon tetrachlorid
+solution of iodin and allowed to stand as above described for fifty
+<span class="pagenum"><a id="Page_370"></a>[Pg 370]</span>
+hours. At the end of this time, 42.3 cubic centimeters of the sodium
+thiosulfate solution were required to decolorize the excess of iodin
+remaining.</p>
+
+<p><i>Statement of Results.</i>—Fifty cubic centimeters of the sodium
+thiosulfate equal 500 milligrams of iodin; therefore, 42.3 cubic
+centimeters of the thiosulfate solution equal 423 milligrams of iodin.
+The difference equals seventy-seven milligrams of iodin absorbed by 101
+milligrams of the flaxseed oil. Therefore, the iodin number equivalent
+and the milligrams of iodin absorbed by 100 milligrams of flaxseed oil
+equal 76.2.</p>
+
+<p>It is evident from the above determination that the iodin number of
+the oil, when obtained in the manner described, is less than half that
+secured by the usual hübl process. Since the solvent employed, however,
+is more stable than chloroform when in contact with iodin or bromin,
+the proposed variation is one worthy of the careful attention of
+analysts.</p>
+
+<p>McIlhiney has called especial attention to the low numbers given by the
+method of Gantter, and from a study of the data obtained concludes that
+iodin alone will not saturate glycerids, no matter what the solvents
+may be.<a id="FNanchor_296" href="#Footnote_296" class="fnanchor">[296]</a></p>
+
+<p>It is clear, therefore, that the process of Gantter cannot give numbers
+which are comparable with those obtained by the usual iodin method. Any
+comparative value possessed by the data given by the process of Gantter
+must be derived by confining it to the numbers secured by the carbon
+tetrachlorid process alone.</p>
+
+<p><b>335. Substitution of Iodin Monochlorid for Hübl’s
+Reagent.</b>—Ephraim has shown that iodin monochlorid may be
+conveniently substituted for the hübl reagent with the advantage
+that it can be safely used at once, while the hübl reagent undergoes
+somewhat rapid changes when first prepared. The present disadvantage of
+the process is found in the fact that the iodin monochlorid of commerce
+is not quite pure and each new lot requires to be titrated for the
+determination of its purity.</p>
+
+<p>The reagent is prepared of such a strength as to contain 16.25 grams of
+iodin monochlorid per liter. The solvent used is alcohol. The operation
+is carried out precisely as in the hübl method, substituting the
+alcoholic solution of iodin monochlorid for the iodin reagent proposed
+<span class="pagenum"><a id="Page_371"></a>[Pg 371]</span>
+by Hübl.<a id="FNanchor_297" href="#Footnote_297" class="fnanchor">[297]</a>
+If the iodin monochlorid solution, after acting on the oil, be titrated
+without previous addition of potassium iodid a new value is obtained,
+the chloriodin number. In titrating, the sodium thiosulfate is added
+until the liquid, which is made brown by the separated iodin, becomes
+yellow. At this point the solution is diluted, starch paste added, and
+the titration completed.</p>
+
+<p><b>336. Preservation of the Hübl Reagent.</b>—To avoid the trouble due
+to changes in the strength of Hübl’s reagent, Mahle adds hydrochloric
+acid to it at the time of its preparation.<a id="FNanchor_298" href="#Footnote_298" class="fnanchor">[298]</a>
+The reagent is prepared as follows: Twenty-five grams of iodin
+dissolved in a quarter of a liter of ninety-five per cent alcohol
+are mixed with the same quantity of mercuric chlorid in 200 cubic
+centimeters of alcohol, the same weight of hydrochloric acid of 1.19
+specific gravity added and the volume of the mixture completed to
+half a liter with alcohol. After five days such a solution gave, on
+titration, 49.18 instead of 49.31 grams per liter of iodin.</p>
+
+<p>It will be observed that this solution is double the usual strength,
+but this does not influence the accuracy of the analytical data
+obtained. It appears that the hübl number is not, therefore, an iodin
+number, but expresses the total quantity of iodin, chlorin and oxygen
+absorbed by the fat during the progress of the reaction.</p>
+
+<p><b>337. Bromin Addition Number.</b>—In the process of Hübl and others
+an attempt is made to determine the quantity of a halogen, <i>e.g.</i>,
+iodin, which the oil, fat or resin will absorb under certain
+conditions. The numbers obtained, however, represent this absorption
+only approximately, because the halogen may disappear through
+substitution as well as absorption. Whether or not a halogen is added,
+<i>i. e.</i>, absorbed or substituted, may be determined experimentally.</p>
+
+<p>The principle on which the determination depends rests on the fact that
+a halogen, <i>e. g.</i>, bromin, forms a molecule of hydrobromic acid
+for every atom of bromin substituted, while in a simple absorption
+of the halogen no such action takes place. If, therefore, bromin be
+brought into contact with a fat, oil or resin, the determination of the
+<span class="pagenum"><a id="Page_372"></a>[Pg 372]</span>
+quantity of hydrobromic acid formed will rigidly determine the quantity
+of bromin substituted during the reaction. If this quantity be deducted
+from the total bromin which has disappeared, the relative quantities of
+the halogen added and substituted are at once determined. In the method
+of McIlhiney<a id="FNanchor_299" href="#Footnote_299" class="fnanchor">[299]</a>
+bromin is used instead of iodin because the addition figures of iodin
+are in general much too low.</p>
+
+<p><i>The Reagents.</i>—The following solutions are employed:</p>
+
+<div class="blockquot">
+<p>1. One-third normal bromin dissolved in carbon tetrachlorid:</p>
+
+<p>2. One-tenth normal sodium thiosulfate:</p>
+
+<p>3. One-tenth normal potassium hydroxid.</p>
+</div>
+
+<p><i>The Manipulation.</i>—From a quarter to one gram of the fat, oil
+or resin, is dissolved in ten cubic centimeters of carbon tetrachlorid
+in a dry bottle of 500 cubic centimeters capacity, provided with a
+well-ground glass stopper. An excess of the bromin solution is added,
+the bottle tightly stoppered, well shaken and placed in the dark. At
+the end of eighteen hours the bottle is placed in a freezing mixture
+and cooled until a partial vacuum is formed. A piece of wide rubber
+tubing an inch and a half long is slipped over the lip of the bottle so
+as to form a well about the stopper. This well having been filled with
+water the stopper is lifted and the water is sucked into the bottle
+absorbing all the hydrobromic acid which has been formed. The well
+should be kept filled with water, as it is gradually taken in until in
+all twenty-five cubic centimeters have been added. The bottle is next
+well shaken and from ten to twenty cubic centimeters of a twenty per
+cent potassium iodid solution added.</p>
+
+<p>The excess of bromin liberates a corresponding amount of iodin, which
+is determined by the thiosulfate solution in the usual way, after
+adding about seventy-five cubic centimeters of water. The total bromin
+which has disappeared is then calculated from the data obtained,
+the strength of the original bromin solution having been previously
+determined. The contents of the bottle are next transferred to a
+separatory funnel, the aqueous portion separated, filtered through a
+linen filter, a few drops of thiosulfate solution added, if a blue
+color persist, and the free hydrobromic acid determined by titration
+with potassium hydroxid, using methyl orange as indicator. The end
+<span class="pagenum"><a id="Page_373"></a>[Pg 373]</span>
+reaction is best observed by placing the solution in a porcelain
+dish, adding the alkali in slight excess, and titrating back with
+tenth-normal hydrochloric acid until the pink tint is perceived.
+From the number of cubic centimeters of alkali used the amount of
+bromin present as hydrobromic acid is calculated, and this expressed
+as percentage gives the bromin substitution figure. The bromin
+substitution figure multiplied by two and subtracted from the total
+absorption gives the addition figure.</p>
+
+<p>Following are the data for some common substances:</p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb" colspan="3">Substance.</th>
+      <th class="tdc bb">Total bromin<br>&nbsp; absorption in &nbsp;<br>eighteen hours.</th>
+      <th class="tdc bb">Bromin<br>&nbsp; addition &nbsp;<br>figure.</th>
+      <th class="tdc bb">Bromin<br>&nbsp; substitution &nbsp;<br>figure.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl" colspan="3">Rosin</td>
+      <td class="tdc">212.70</td>
+      <td class="tdc">&#8199;0.00</td>
+      <td class="tdc">106.35&#8199;</td>
+   </tr><tr>
+      <td class="tdl">Raw</td>
+      <td class="tdl_wsp">linseed</td>
+      <td class="tdl_wsp">oil</td>
+      <td class="tdc">102.88</td>
+      <td class="tdc">102.88</td>
+      <td class="tdc">00.00</td>
+   </tr><tr>
+      <td class="tdl">Boiled</td>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdc">103.92</td>
+      <td class="tdc">103.92</td>
+      <td class="tdc">00.00</td>
+   </tr><tr>
+      <td class="tdl">Salad</td>
+      <td class="tdl_wsp">cotton</td>
+      <td class="tdc">”</td>
+      <td class="tdc">&#8199;65.54</td>
+      <td class="tdc">&#8199;64.26</td>
+      <td class="tdc">&#8199;0.64</td>
+   </tr><tr>
+      <td class="tdl">Sperm</td>
+      <td class="tdl_wsp">&nbsp;</td>
+      <td class="tdc">”</td>
+      <td class="tdc">&#8199;56.60</td>
+      <td class="tdc">&#8199;54.52</td>
+      <td class="tdc">&#8199;1.04</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>By the process just described it is possible to detect mixtures of
+rosins and rosin oils with animal and vegetable oils. In this respect
+it possesses undoubted advantages over the older methods.</p>
+
+<p><b>338. Method Of Hehner.</b>—The absorption of bromin which takes
+place when unsaturated fats are brought into contact with that reagent
+was made the basis of an analytical process, proposed by Allen as
+long ago as 1880.<a id="FNanchor_300" href="#Footnote_300" class="fnanchor">[300]</a>
+In the further study of the phenomena of bromin absorption, as
+indicated by McIlhiney, Hehner modified the method as indicated
+below.<a id="FNanchor_301" href="#Footnote_301" class="fnanchor">[301]</a>
+From one to three grams of the sample are placed in a tared
+wide-mouthed flask and dissolved in a little chloroform. Bromin is
+added to the solution, drop by drop, until it is in decided excess.
+The flask is placed on a steam-bath and heated until the greater
+part of the bromin is evaporated, when some more chloroform is added
+and the heating continued until all the free bromin has escaped. The
+flask is put in a bath at 125° and dried to constant weight. A little
+acrolein and hydrobromic acid escape during the drying and the residue
+may be colored, or a heavy bromo oil be obtained. The gain in weight
+<span class="pagenum"><a id="Page_374"></a>[Pg 374]</span>
+represents the bromin absorbed. The bromin number may be converted into
+the iodin number by multiplying by 1.5875.<a id="FNanchor_302" href="#Footnote_302" class="fnanchor">[302]</a></p>
+
+<div class="figleft smcap">
+    <img id="FIG_100" src="images/fig100.jpg" alt="" width="100" height="365" >
+    <p class="center">Fig. 100.—<br>Olein<br> Tube.</p>
+</div>
+
+<p id="P_339"><b>339. Halogen Absorption and Addition of Fat Acids.</b>—Instead of
+employing the natural glycerids for determining the degree of action
+with the halogens the acids may be separated by some of the processes
+of saponification hereafter described and used as directed for the
+glycerids themselves. It is doubtful if any practical advantage arises
+from this variation of the process. If the fat acids be separated,
+however, it is possible to get some valuable data from the halogen
+absorption of the fractions. Theoretically the stearic series of acids
+would suffer no change in contact with halogens while the oleic series
+is capable of a maximum absorptive and additive action. On this fact is
+based a variation of the iodin process in which an attempt is made to
+separate the oleic acid from its congeners and to apply the halogen to
+the separated product.</p>
+
+<p>The method of separation devised by Muter is carried out as
+follows:<a id="FNanchor_303" href="#Footnote_303" class="fnanchor">[303]</a>
+The separatory or olein tube consists of a wide burette stem, provided
+with a lateral stopcock, and drawn out below to secure a clamp delivery
+tube, and at the top expanded into a bulb closed with a ground glass
+stopper, as shown in <a href="#FIG_100">Fig. 100</a>. Forty cubic centimeters
+of liquid are placed in the tube and the surface is marked 0. Above this the
+graduation is continued in cubic centimeters to 250, which figure is
+just below the bulb at the top.</p>
+
+<p>The process of analysis is conducted as follows: About three grams of
+the oil or fat are placed in a flask, with fifty cubic centimeters of
+alcoholic potash lye, containing enough potassium hydroxid to ensure
+complete saponification. The flask is closed and heated on a water-bath
+until saponification is complete. The pressure flask to be described
+hereafter may be conveniently used. After cooling, the excess of alkali
+is neutralized with acetic acid in presence of phenolphthalien and then
+alcoholic potash added until a faint pink color is produced. In a large
+porcelain dish place 200 cubic centimeters of water and thirty of a ten
+per cent solution of lead acetate and boil. Pour slowly, with constant
+<span class="pagenum"><a id="Page_375"></a>[Pg 375]</span>
+stirring, into the boiling liquid the soap solution prepared as above
+described, and allow to cool, meanwhile continuing the stirring. At the
+end, the liquid remaining is poured off and the solid residue washed
+with hot water by decantation.</p>
+
+<p>The precipitate of lead salts is finally removed from the dish into a
+stoppered bottle, the dish washed with pure ether, the washings added
+to the bottle together with enough ether to make the total volume
+thereof 120 cubic centimeters. The closed bottle is allowed to stand
+for twelve hours with occasional shaking, by which time the lead oleate
+will have been completely dissolved. The insoluble lead salts are next
+separated by filtration, and the filtrate collected in the olein tube.
+The washing is accomplished by ether and, to avoid loss, the funnel
+is covered with a glass plate. The ethereal solution of lead oleate
+is decomposed by dilute hydrochloric acid, using about forty cubic
+centimeters of a mixture containing one part of strong acid to four
+of water. The olein tube is closed and shaken until the decomposition
+is complete, which will be indicated by the clearing of the ethereal
+solution. The tube is allowed to remain at rest until the liquids
+separate and the aqueous solution is run out from the pinch-cock at the
+lower end. The residue is washed with water by shaking, the water drawn
+off as just described, and the process continued until all acidity is
+removed.</p>
+
+<p>Water is then added until the separating plane between the two liquids
+is at the zero of the graduation, and enough ether added to make the
+ethereal solution of a desired volume, say 200 cubic centimeters.
+After well mixing, the ethereal solution or an aliquot part thereof,
+<i>e.g.</i>, fifty cubic centimeters, is removed by the side tubulure
+and nearly the whole of the ether removed from the portion by
+distillation. To the residue are added fifty cubic centimeters of pure
+alcohol and the solution is titrated for oleic acid with decinormal
+sodium hydroxid solution. Each cubic centimeter of the hydroxid
+solution used is equivalent to 0.0282 gram of oleic acid. The total
+quantity of oleic acid contained in the amount of fat used is readily
+calculated from the data obtained.
+<span class="pagenum"><a id="Page_376"></a>[Pg 376]</span></p>
+
+<p>To determine the iodin absorption of the free acid another measured
+quantity of the ethereal solution containing as nearly as possible half
+a gram of oleic acid, is withdrawn from the olein tube, and the ether
+removed in an atmosphere of pure carbon dioxid. To the residue, without
+allowing it to come in contact with the air, fifty cubic centimeters
+of Hübl’s reagent are added and the flask put aside in the dark for
+twelve hours. At the end of this time thirty-five cubic centimeters of
+a ten per cent solution of potassium iodid are added, the contents of
+the flask made up to a quarter of a liter with water, fifteen cubic
+centimeters of chloroform added, and the excess of iodin titrated
+in the way already described. The percentage of iodin absorbed is
+calculated as already indicated.</p>
+
+<p>Lane has proposed a more rapid process for the above determination.<a id="FNanchor_304" href="#Footnote_304" class="fnanchor">[304]</a>
+The lead soaps are precipitated in a large erlenmeyer and cooled
+rapidly in water, giving the flask meanwhile a circular motion which
+causes the soaps to adhere to its walls. Wash with hot water, rinsing
+once with alcohol, add 120 cubic centimeters of ether, attach a reflux
+condenser, and boil until the lead oleate is dissolved, cool slowly, to
+allow any lead stearate which has passed into solution to separate, and
+filter into the olein tube. The rest of the operation is conducted as
+described above. The percentage of oleic acid and its iodin absorption
+in the following glycerids are given in the table below:</p>
+
+<table class="spb1">
+   <tbody><tr class="fs_90">
+      <td class="tdl">&nbsp;</td>
+      <td class="tdc">Cottonseed<br> oil.</td>
+      <td class="tdc">&nbsp;&emsp;Lard.&emsp;&nbsp;</td>
+      <td class="tdc">Peanut oil.</td>
+   </tr><tr>
+      <td class="tdl">Per cent oleic acid</td>
+      <td class="tdc">&#8199;75.16</td>
+      <td class="tdc">64.15</td>
+      <td class="tdc">&#8199;79.84</td>
+   </tr><tr>
+      <td class="tdl">Per cent iodin absorbed</td>
+      <td class="tdc">141.96</td>
+      <td class="tdc">99.48</td>
+      <td class="tdc">114.00</td>
+   </tr>
+ </tbody>
+</table>
+
+<p id="P_340"><b>340. Saponification.</b>—In many of the analytical operations which
+are conducted on the glycerids it is necessary to decompose them.
+When this is accomplished by the action of a base which displaces
+the glycerol from its combination with the fat acids, the resulting
+salts are known as soaps and the process is named saponification. In
+general use the term saponification is applied, not only strictly, as
+above defined, but also broadly, including the setting free of the
+glycerol either by the action of strong acids or by the application
+of superheated steam. In chemical processes the saponification of a
+<span class="pagenum"><a id="Page_377"></a>[Pg 377]</span>
+glycerid is almost always accomplished by means of soda or potash
+lye. This may be in aqueous or alcoholic solution and the process is
+accomplished either hot or cold, in open vessels or under pressure.
+It is only important that the alkali and glycerid be brought into
+intimate contact. The rate of saponification is a function of the
+intimacy of contact, the nature of the solvent and the temperature. For
+chemical purposes, it is best that the decomposition of the glycerid be
+accomplished at a low temperature and for most samples this is secured
+by dissolving the alkali in alcohol.</p>
+
+<p>In respect of solvents, that one would be most desirable, from
+theoretical considerations, which acts on both the glycerids and
+alkalies. In the next rank would be those which dissolve one or the
+other of the materials and are easily miscible, as, for instance,
+carbon tetrachlorid for the glycerid and alcohol for the alkali.
+As a rule, the glycerid is not brought into solution before the
+saponification process is commenced. Instead of using an alcoholic
+solution of sodium or potassium hydroxid the sodium or potassium
+alcoholate may be employed, made by dissolving metallic sodium or
+potassium in alcohol. It is probable, however, that a little water is
+always necessary to complete the process.</p>
+
+<p>If a fat be dissolved in ether and treated with sodium alcoholate,
+a granular deposit of soap is soon formed and the saponification is
+completed in twenty-four hours. As much as 150 grams of fat can be
+saponified with ten grams of metallic sodium dissolved in 250 cubic
+centimeters of absolute alcohol.<a id="FNanchor_305" href="#Footnote_305" class="fnanchor">[305]</a>
+For practical purposes the alcoholic solution of the hydroxid is sufficient.</p>
+
+<p>The chemical changes which fats undergo on saponification are of a
+simple kind. When the process is accomplished by means of alkalies,
+the alkaline base takes the place of the glycerol as indicated in the
+following equation:</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdc">Triolein 884.</td>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdl">&nbsp; Potassium<br> hydroxid 168.</td>
+      <td class="tdl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">C₃H₅(O.C₁₈H₃₃O)₃</td>
+      <td class="tdc">&nbsp; + &nbsp;</td>
+      <td class="tdl">&nbsp;&emsp;3KOH</td>
+      <td class="tdl">&nbsp; =</td>
+   </tr><tr>
+      <td class="tdc" colspan="4">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">&nbsp; Potassium<br>&nbsp; oleate 960.</td>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdl">Glycerol 92.</td>
+      <td class="tdl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">(KO.C₁₈H₃₃O)₃</td>
+      <td class="tdl">&nbsp; + &nbsp;</td>
+      <td class="tdc">C₃H₅(OH)₃.</td>
+      <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The actual changes which take place in ordinary saponification are
+not so simple, however, since natural glycerids are mixtures of
+several widely differing fats, each of which has its own rate of
+<span class="pagenum"><a id="Page_378"></a>[Pg 378]</span>
+decomposition. Palmitin and stearin, for instance, are saponified more
+readily than olein and some of the saponifiable constituents of resins
+and waxes are extremely resistant to the action of alkalies. The above
+equation may be regarded as typical for saponification in aqueous or
+alcoholic solutions in open dishes or under pressure. If the alkali
+used be prepared by dissolving metallic sodium or potassium in absolute
+alcohol (sodium alcoholate or ethoxid) the reaction which takes place
+is probably represented by the equation given below:</p>
+
+<p class="f105">C₃H₅(O.C₁₈H₃₃O)₃ + 3C₂H₅.ONa = C₃H₅(ONa)₃ + 3C₁₈H₃₃O.O.C₂H₅,</p>
+
+<p class="no-indent">in which it is seen that complete saponification
+cannot occur without the absorption of some water, by which the sodium
+glyceroxid is converted into glycerol and sodium hydroxid, the latter
+compound eventually uniting with the ethyl ether of the fat acid.<a id="FNanchor_306" href="#Footnote_306" class="fnanchor">[306]</a></p>
+
+<p>Glycerids are decomposed when heated with water under a pressure of
+about sixteen atmospheres or when subjected to a current of superheated
+steam at 200°. The reaction consists in the addition of the elements
+of water, whereby the glyceryl radicle is converted into free glycerol
+and the fat acid is set free. The chemical change which ensues is shown
+below:</p>
+
+<p class="f105">C₃H₅(O.C₁₈H₃₃O)₃ + 3H₂O = 3C₁₈H₃₄O₂ + C₃H₅(OH)₃.</p>
+
+<p>The details of saponification with sulfuric acid are of no interest
+from an analytical point of view.<a id="FNanchor_307" href="#Footnote_307" class="fnanchor">[307]</a></p>
+
+<p id="P_341"><b>341. Saponification in an Open Dish.</b>—The simplest method of
+saponifying fats is to treat them with the alkaline reagent in an
+open dish. In all cases the process is accelerated by the application
+of heat. Vigorous stirring also aids the process by securing a more
+intimate mixture of the ingredients. This method of decomposing
+glycerids, however, is not applicable in cases where volatile ethers
+may be developed. These ethers may escape saponification and thus
+prevent the formation of the maximum quantity of soap. While not suited
+to exact quantitive work, the method is convenient in the preparation
+of fat acids which are to be the basis of subsequent analytical
+<span class="pagenum"><a id="Page_379"></a>[Pg 379]</span>
+operations, as, for instance, in the preparation of fat acids for
+testing with silver nitrate. Large porcelain dishes are conveniently
+used and the heat is applied in any usual way, with care to avoid
+scorching the fat.</p>
+
+<p><b>342. Saponification under Pressure.</b>—The method of
+saponification which has given the best satisfaction in my work and
+which has been adopted by the Association of Official Agricultural
+Chemists is described below.<a id="FNanchor_308" href="#Footnote_308" class="fnanchor">[308]</a></p>
+
+<p><i>Reagents.</i>—The reagents employed are a solution of pure potash
+containing 100 grams of the hydroxid dissolved in fifty-eight grams of
+recently boiled distilled water, alcohol of approximately ninety-five
+per cent strength redistilled over caustic soda, and sodium hydroxid
+solution prepared as follows:</p>
+
+<p>One hundred grams of sodium hydroxid are dissolved in 100 cubic
+centimeters of distilled water. The caustic soda should be as free as
+possible from carbonates, and be preserved from contact with the air.</p>
+
+<p><i>Apparatus.</i>—A saponification flask; it has a round bottom and a
+ring near the top, by means of which the stopper can be tied down. The
+flask is arranged for heating as shown in <a href="#FIG_101">Fig. 101</a>.
+A pipette graduated to deliver forty cubic centimeters is recommended
+as being more convenient than a burette for measuring the solutions: A
+pipette with a long stem graduated to deliver 5.75 cubic centimeters at 50°.</p>
+
+<p><i>Manipulation.</i>—The fat to be examined should be melted and kept
+in a dry warm place at about 60° for two or three hours, until the
+water has entirely separated. The clear supernatant fat is poured off
+and filtered through a dry filter paper in a jacket funnel containing
+boiling water. Should the filtered fat, in a fused state, not be
+perfectly clear, it must be filtered a second time. The final drying is
+accomplished at 100° in a thin layer in a flat bottom dish, in partial
+vacuum or an atmosphere of inert gas.</p>
+
+<p>The saponification flasks are prepared by thoroughly washing with
+water, alcohol, and ether, wiping perfectly dry on the outside,
+and heating for one hour at the temperature of boiling water. The
+hard flasks used in moist combustions with sulfuric acid for the
+<span class="pagenum"><a id="Page_380"></a>[Pg 380]</span>
+determination of nitrogen are well suited for this work. The flasks
+should be placed in a tray by the side of the balance and covered with
+a silk handkerchief until they are perfectly cool. They must not be
+wiped with a silk handkerchief within fifteen or twenty minutes of the
+time they are weighed or else the electricity developed will interfere
+with weighing. The weight of the flasks having been accurately
+determined, they are charged with the melted fat in the following way:</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_101" src="images/fig101.jpg" alt="" width="500" height="617" >
+    <p class="center spb1">Fig. 101.—Apparatus for Saponifying under Pressure.</p>
+</div>
+
+<p>The pipette with a long stem, marked to deliver 5.75 cubic centimeters,
+is warmed to a temperature of about 50°. The fat, having been poured
+back and forth once or twice into a dry beaker in order to thoroughly
+mix it, is taken up in the pipette, the nozzle of the pipette having
+been previously wiped to remove any externally adhering fat, is carried
+to near the bottom of the flask and 5.75 cubic centimeters of fat
+allowed to flow into the flask. After the flasks have been charged in
+<span class="pagenum"><a id="Page_381"></a>[Pg 381]</span>
+this way they should be re-covered with the silk handkerchief and allowed
+to stand for fifteen or twenty minutes, when they are again weighed.</p>
+
+<p><b>343. Methods of Saponification.</b>—<i>In the Presence of
+Alcohol.</i>—Ten cubic centimeters of ninety-five per cent alcohol
+are added to the fat in the flask, and then two cubic centimeters of
+the sodium hydroxid solution. A soft cork stopper is inserted and
+tied down with a piece of twine. The saponification is completed by
+placing the flask upon the water or steam-bath. The flask during the
+saponification, which should last one hour, should be gently rotated
+from time to time, being careful not to project the soap for any
+distance up its sides. At the end of an hour the flask, after having
+been cooled to near the room temperature, is opened.</p>
+
+<p><i>Without the Use of Alcohol.</i>—To avoid the danger of loss from
+the formation of ethers, and the trouble of removing the alcohol
+after saponification, the fat may be saponified with a solution of
+caustic potash in a closed flask without using alcohol. The operation
+is carried on exactly as indicated above for saponification in the
+presence of alcohol, using potassium instead of sodium hydroxid
+solution. For the saponification, use two cubic centimeters of the
+potassium hydroxid solution which are poured on the fat after it has
+solidified in the flask. Great care must be taken that none of the
+fat be allowed to rise on the sides of the saponifying flask to a
+point where it cannot be reached by the alkali. During the process of
+saponification the flask can only be very gently rotated in order to
+avoid the difficulty mentioned. This process is not recommended with
+any apparatus except a closed flask with round bottom. Potash is used
+instead of soda so as to form a softer soap and thus allow a more
+perfect saponification.</p>
+
+<p>The saponification may also be conducted as follows: The alkali and fat
+in the melted state are shaken vigorously in the saponification flask
+until a complete emulsion is secured. The rest of the operation is then
+conducted as above.</p>
+
+<p><b>344. Saponification in the Cold.</b>—By reason of the danger of
+loss from volatile ethers in the hot alcoholic saponification, a method
+<span class="pagenum"><a id="Page_382"></a>[Pg 382]</span>
+for successfully conducting the operation in the cold is desirable.
+Such a process has been worked out by Henriques.<a id="FNanchor_309" href="#Footnote_309" class="fnanchor">[309]</a>
+It is based upon the previous solution of the fat in petroleum ether,
+in which condition it is so easily attacked by the alcoholic alkali
+as to make the use of heat during the saponification unnecessary. The
+process is conveniently conducted in a porcelain dish covered with a
+watch glass. Five grams of the fat are dissolved in twenty-five cubic
+centimeters of petroleum ether and treated with an equal quantity
+of four per cent alcoholic soda lye. The process of saponification
+begins at once and is often indicated by the separation of sodium
+salts. It is best to allow the action to continue over night and,
+with certain difficultly saponifiable bodies, such as wool fat and
+waxes, for twenty-four hours. In the case of butter fat an odor of
+butyric ether may be perceived at first but it soon disappears. After
+the saponification is complete, the excess of alkali is determined
+by titration in the usual way with set hydrochloric acid, using
+phenolphthalien as indicator. For the determination of volatile acids,
+the mixture, after saponification is complete, is evaporated rapidly
+to dryness, the solid matter being reduced to powder with a glass
+rod, after which it is transferred to a distilling flask and the
+volatile acids secured by the usual processes. In comparison with the
+saponification and reichert-meissl numbers obtained with hot alcoholic
+potash, the numbers given by the cold process are found to be slightly
+higher with those fats which give easily volatile ethers. On account of
+the simplicity of the process and the absence of danger of loss from
+ethers, it is to be recommended instead of the older methods in case
+a more extended trial of it should establish the points of excellence
+claimed above.</p>
+
+<p id="P_345"><b>345. Saponification Value.</b>—The number of milligrams of
+potassium hydroxid required to completely saturate one gram of a fat
+is known as the saponification value of the glycerid. The process of
+determining this value, as worked out by Koettstorfer and modified in
+the laboratory of the Department of Agriculture, is as
+follows:<a id="FNanchor_310" href="#Footnote_310" class="fnanchor">[310]</a></p>
+
+<p><span class="pagenum"><a id="Page_383"></a>[Pg 383]</span>
+The saponification is accomplished with the aid of potassium hydroxid
+and in the flask and manner described in the preceding paragraph. About
+two grams of the fat will be found a convenient quantity. Great care
+must be exercised in measuring the alkaline solution, the same pipette
+being used in each case and the same time for draining being allowed in
+every instance. Blanks are always to be conducted with each series of
+examinations. As soon as the saponification is complete, the flask is
+removed from the bath, allowed to cool and its contents are titrated
+with seminormal hydrochloric acid and phenolphthalien as indicator.
+The number expressing the saponification value is obtained by
+subtracting the number of cubic centimeters of seminormal hydrochloric
+acid required to neutralize the alkali after saponification from
+that required to neutralize the alkali of the blank determinations,
+multiplying the result by 28.06 and dividing the product by the number
+of grams of fat employed.</p>
+
+<div class="blockquot">
+<p><i>Example.</i>—Weight of sample of fat used 1.532 grams: Number of
+cubic centimeters half normal hydrochloric acid required to saturate
+blank, 22.5: Number of cubic centimeters of half normal hydrochloric
+acid required to saturate the alkali after saponification 12.0:
+Difference, 10.5 cubic centimeters:</p>
+
+<p>Then 10.50 × 28.06 ÷ 1.532 = 192.3.</p>
+
+<p>This latter number represents the saponification value of the sample.</p>
+</div>
+
+<p><b>346. Saponification Equivalent.</b>—Allen defines the
+saponification equivalent as the number of grams of fat saponified by
+one equivalent, <i>viz.</i>, 56.1 grams of potassium hydroxid.<a id="FNanchor_311" href="#Footnote_311" class="fnanchor">[311]</a>
+The saponification equivalent is readily calculated from the saponification
+value using it as a divisor and 56100 as a dividend. Conversely
+the saponification value may be obtained by dividing 56100 by the
+saponification equivalent. No advantage is gained by the introduction
+of a new term so nearly related to saponification value.</p>
+
+<p><b>347. Saponification Value of Pure Glycerids.</b>—The theoretical
+<span class="pagenum"><a id="Page_384"></a>[Pg 384]</span>
+saponification values of pure glycerids are given in the following
+table.<a id="FNanchor_312" href="#Footnote_312" class="fnanchor">[312]</a></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb">Name.</th>
+      <th class="tdc bb">Symbol.</th>
+      <th class="tdc bb">Molecular<br>weight.</th>
+      <th class="tdc bb">&nbsp; Saponification<br>value.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Butyrin</td>
+      <td class="tdl_ws1 fs_110">C₃H₅(O.C₄H₇O)₃</td>
+      <td class="tdc">302</td>
+      <td class="tdc">557.3</td>
+   </tr><tr>
+      <td class="tdl">Valerin</td>
+      <td class="tdl_ws1 fs_110">C₃H₅(O.C₅H₉O)₃</td>
+      <td class="tdc">344</td>
+      <td class="tdc">489.2</td>
+   </tr><tr>
+      <td class="tdl">Caproin</td>
+      <td class="tdl_ws1 fs_110">C₃H₅(O.C₆H₁₁O)₃</td>
+      <td class="tdc">386</td>
+      <td class="tdc">438.3</td>
+   </tr><tr>
+      <td class="tdl">Caprin</td>
+      <td class="tdl_ws1 fs_110">C₃H₅(O.C₁₀H₁₉O)₃</td>
+      <td class="tdc">554</td>
+      <td class="tdc">305.0</td>
+   </tr><tr>
+      <td class="tdl">Laurin</td>
+      <td class="tdl_ws1 fs_110">C₃H₅(O.C₁₂H₂₃O)₃</td>
+      <td class="tdc">638</td>
+      <td class="tdc">263.8</td>
+   </tr><tr>
+      <td class="tdl">Myristin</td>
+      <td class="tdl_ws1 fs_110">C₃H₅(O.C₁₄H₂₇O)₃</td>
+      <td class="tdc">722</td>
+      <td class="tdc">233.1</td>
+   </tr><tr>
+      <td class="tdl">Palmitin</td>
+      <td class="tdl_ws1 fs_110">C₃H₃(O.C₁₆H₃₁O)₃</td>
+      <td class="tdc">806</td>
+      <td class="tdc">208.8</td>
+   </tr><tr>
+      <td class="tdl">Stearin</td>
+      <td class="tdl_ws1 fs_110">C₃H₅(O.C₁₈H₃₅O)₃</td>
+      <td class="tdc">890</td>
+      <td class="tdc">189.1</td>
+   </tr><tr>
+      <td class="tdl">Olein</td>
+      <td class="tdl_ws1 fs_110">C₃H₅(O.C₁₈H₃₃O)₃</td>
+      <td class="tdc">884</td>
+      <td class="tdc">190.4</td>
+   </tr><tr>
+      <td class="tdl">Linolein</td>
+      <td class="tdl_ws1 fs_110">C₃H₅(O.C₁₈H₃₁O)₃</td>
+      <td class="tdc">878</td>
+      <td class="tdc">191.7</td>
+   </tr><tr>
+      <td class="tdl">Ricinolein</td>
+      <td class="tdl_ws1 fs_110">C₃H₅(O.C₁₈H₃₃O₂)₃</td>
+      <td class="tdc">932</td>
+      <td class="tdc">180.6</td>
+   </tr><tr>
+      <td class="tdl">Euricin</td>
+      <td class="tdl_ws1 fs_110">C₃H₅(O.C₂₂H₁₄O)₃</td>
+      <td class="tdc">1052&#8199;</td>
+      <td class="tdc">160.0</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>From the above table it is seen that in each series of glycerids the
+saponification equivalent falls as the molecular weight rises.</p>
+
+<p><b>348. Acetyl Value.</b>—Hydroxy acids and alcohols, when heated with
+glacial acetic acid, undergo a change which consists in substituting
+the radicle of acetic acid for the hydrogen atom of the alcoholic
+hydroxyl group. This change is illustrated by the equations below:<a id="FNanchor_313" href="#Footnote_313" class="fnanchor">[313]</a></p>
+
+<div class="blockquot">
+<p><i>For a Fat Acid</i>:</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdc">Ricinoleic acid.</td>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdl">Acetic anhydrid.</td>
+      <td class="tdl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">C₁₇H₃₂(OH).COOH</td>
+      <td class="tdl">&nbsp; + &nbsp;</td>
+      <td class="tdl">(C₂H₃O)₂O</td>
+      <td class="tdl">&nbsp; =</td>
+   </tr><tr>
+      <td class="tdc" colspan="4">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">Acetyl-ricinoleic acid.</td>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdl">Acetic acid.</td>
+      <td class="tdl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">C₁₇H₃₂(O.C₂H₃O)COOH</td>
+      <td class="tdl">&nbsp; + &nbsp;</td>
+      <td class="tdl">HC₂H₃O₂.</td>
+      <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><i>For an Alcohol</i>:</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdc">Cetyl alcohol.</td>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdl">Acetic anhydrid.</td>
+      <td class="tdl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">C₁₆H₃₃.OH</td>
+      <td class="tdl">&nbsp; + &nbsp;</td>
+      <td class="tdl">(C₂H₃O)₂O</td>
+      <td class="tdl">&nbsp; =</td>
+   </tr><tr>
+      <td class="tdc" colspan="4">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">Cetyl acetate.</td>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdl">Acetic acid.</td>
+      <td class="tdl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">C₁₆H₃₃.C₂H₃O</td>
+      <td class="tdl">&nbsp; + &nbsp;</td>
+      <td class="tdl">HC₂H₃O₂.</td>
+      <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+</div>
+
+<p><i>Determination.</i>—The method of determining the acetyl value
+of a fat or alcohol has been described by Benedikt and Ulzer.<a id="FNanchor_314" href="#Footnote_314" class="fnanchor">[314]</a>
+The operation is conducted on the fat acids and not on the glycerids
+containing them.</p>
+
+<p>The insoluble fat acids are prepared as directed in paragraph
+<b><a href="#P_340">340</a></b>.</p>
+
+<p>From twenty to fifty grams of the fat acids are boiled with an equal
+volume of acetic anhydrid, in a flask with a reflux condenser, for two
+hours. The contents of the flask are transferred to a larger vessel of
+<span class="pagenum"><a id="Page_385"></a>[Pg 385]</span>
+about one liter capacity, mixed with half a liter of water and boiled
+for half an hour. To prevent bumping, some bubbles of carbon dioxid
+are drawn through the liquid by means of a tube drawn out to a fine
+point and extending nearly to the bottom of the flask. The liquids
+are allowed to separate into two layers and the water is removed with
+a syphon. The oily matters are treated several times with boiling
+water until the acetic acid is all washed out. The acetylated fat
+acids are filtered through a dry hot jacket filter and an aliquot
+part, from three to five grams, is dissolved in absolute alcohol.
+After the addition of phenolphthalien the mixture is titrated as in
+the determination of the saponification value. The acid value thus
+obtained is designated as the acetyl acid value. A measured quantity
+of alcoholic potash, standardized by seminormal hydrochloric acid,
+is added, the mixture boiled and the excess of alkali determined by
+titration. The quantity of alkali consumed in this process measures the
+acetyl value. The sum of the acetyl acid and the acetyl values is the
+acetyl saponification value. The acetyl value is therefore equal to
+the difference of the saponification and acid values of the acetylated
+fat acids. In other words, the acetyl value indicates the number of
+milligrams of potassium hydroxid required to neutralize the acetic acid
+obtained by the saponification of one gram of the acetylated fat acids.</p>
+
+<p class="blockquot"><i>Example.</i>—A portion of the fat acids acetylated as described,
+weighing 3.379 grams, is exactly neutralized by 17.2 cubic centimeters
+of seminormal potassium hydroxid solution, corresponding to 17.2 ×
+0.02805 = 0.4825 gram of the hydroxid, hence 0.4825 × 1000 ÷ 3.379 =
+142.8, the acetyl acid value of the sample.</p>
+
+<p>After the addition of 32.8 cubic centimeters more of the seminormal
+potash solution, the mixture is boiled to saponify the acetylated
+fat acids. The residual potash requires 14.2 cubic centimeters of
+seminormal hydrochloric acid. The quantity of potash required for
+the acetic acid is therefore 32.8 - 14.3 = 18.5 cubic centimeters or
+18.5 × 0.02805 = 0.5189 gram of potassium hydroxid. Then 0.5189 ×
+1000 ÷ 3.379 = 153.6 = acetyl value of sample. The sum of these two
+values, <i>viz.</i>, 142.8 and 153.6 is 296.4, which is the acetyl
+<span class="pagenum"><a id="Page_386"></a>[Pg 386]</span>
+saponification value of the sample. As with the iodin numbers, however,
+it is also found that acids of the oleic series give an acetyl value
+when treated as above, and it has been proposed by Lewkowitsch to
+determine, in lieu of the data obtained, the actual quantity of acetic
+acid absorbed by fats.<a id="FNanchor_315" href="#Footnote_315" class="fnanchor">[315]</a>
+This is accomplished by saponifying the acetylated product with
+alcoholic potash and determining the free acetic acid by distillation,
+in a manner entirely analogous to that used for estimating volatile fat
+acids described further on.</p>
+
+<p>The rôle which the acetyl value plays in analytical determinations is
+interesting, but the data it gives are not to be valued too highly.</p>
+
+<p id="P_349"><b>349. Determination of Volatile Fat Acids.</b>—The fat acids which
+are volatile at the temperature of boiling water, consist chiefly of
+butyric and its associated acids occurring in the secretions of the
+mammary glands. Among vegetable glycerids cocoanut oil is the only
+common one which has any notable content of volatile acids. The boiling
+points of the above acids, in a pure state, are much higher than the
+temperature of boiling water; for instance, butyric acid boils at about
+162°. By the expression volatile acids, in analytical practice, is
+meant those which are carried over at 100°, or a little above, with
+the water vapor, whatever be their boiling point. The great difficulty
+of removing the volatile from the non-volatile fat acids has prevented
+the formulation of any method whereby a sharp and complete separation
+can be accomplished. The analyst, at the present time, must be content
+with some approximate process which, under like conditions, will give
+comparable results. Instead, therefore, of attempting a definite
+determination, he confines his work to securing a partial separation
+and in expressing the degree of volatile acidity in terms of a standard
+alkali. To this end, a definite weight of the fat is saponified, the
+resulting soap decomposed with an excess of fixed acid, and a definite
+volume of distillate collected and its acidity determined by titration
+with decinormal alkali. The weight of fat operated on is either two and
+a half<a id="FNanchor_316" href="#Footnote_316" class="fnanchor">[316]</a>
+or five grams.<a id="FNanchor_317" href="#Footnote_317" class="fnanchor">[317]</a></p>
+
+<p>Numerous minor variations have been proposed in the process, the most
+important of which is in the use of phosphoric instead of sulfuric acid
+<span class="pagenum"><a id="Page_387"></a>[Pg 387]</span>
+in the distillation. An extended experience with both acids has shown
+that no danger is to be apprehended in the use of sulfuric acid and
+that on the whole it is to be preferred to phosphoric.<a id="FNanchor_318" href="#Footnote_318" class="fnanchor">[318]</a></p>
+
+<p>The process as used in this laboratory and as adopted by the official
+agricultural chemists is conducted as follows:<a id="FNanchor_319" href="#Footnote_319" class="fnanchor">[319]</a></p>
+
+<p><b>350. Removal of the Alcohol.</b>—The saponification is accomplished
+in the manner already described, (<b><a href="#P_341">341-344</a></b>) and when alcoholic
+potash is used proceed as follows:</p>
+
+<p>The stopper having been laid loosely in the mouth of the flask, the
+alcohol is removed by dipping the flask into a steam-bath. The steam
+should cover the whole of the flask except the neck. After the alcohol
+is nearly removed, frothing may be noticed in the soap, and to avoid
+any loss from this cause or any creeping of the soap up the sides of
+the flask, it should be removed from the bath and shaken to and fro
+until the frothing disappears. The last traces of alcohol vapor may be
+removed from the flask by waving it briskly, mouth down, to and fro.</p>
+
+<p><i>Dissolving the Soap.</i>—After the removal of the alcohol the
+soap should be dissolved by adding 100 cubic centimeters of recently
+boiled distilled water, or eighty cubic centimeters when aqueous
+potassium hydroxid has been used for saponification, and warming on the
+steam-bath, with occasional shaking, until the solution of the soap is
+complete.</p>
+
+<p><i>Setting free the Fat Acids.</i>—When the soap solution has cooled
+to about 60° or 70°, the fat acids are separated by adding forty cubic
+centimeters of dilute sulfuric acid solution containing twenty-five
+grams of acid in one liter, or sixty cubic centimeters when aqueous
+potassium hydroxid has been used for saponification.</p>
+
+<p><i>Melting the Fat Acid Emulsion.</i>—The flask is restoppered as in
+the first instance and the fat acid emulsion melted by replacing the
+flask on the steam-bath. According to the nature of the fat examined,
+the time required for the fusion of the fatty acid emulsions may vary
+from a few minutes to several hours.</p>
+
+<p><i>The Distillation.</i>—After the fat acids are completely melted,
+which can be determined by their forming a transparent, oily layer on
+<span class="pagenum"><a id="Page_388"></a>[Pg 388]</span>
+the surface of the water, the flask is cooled to room temperature,
+and a few pieces of pumice stone added. The pumice stone is prepared
+by throwing it, at a white heat, into distilled water, and keeping it
+under water until used. The flask is connected with a glass condenser,
+<a href="#FIG_102">Fig. 102</a>, slowly heated with a naked flame
+until ebullition begins, and then the distillation continued by
+regulating the flame in such a way as to collect 110 cubic centimeters
+of the distillate in, as nearly as possible, thirty minutes. The
+distillate should be received in a flask accurately marked at 110 cubic
+centimeters.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_102" src="images/fig102.jpg" alt="" width="600" height="390" >
+    <p class="center spb1">Fig. 102.—Apparatus for the Distillation of Volatile Acids.</p>
+</div>
+
+<p><i>Titration of the Volatile Acids.</i>—The 110 cubic centimeters
+of distillate, after thorough mixing, are filtered through perfectly
+dry filter paper, 100 cubic centimeters of the filtered distillate
+poured into a beaker holding about a quarter of a liter, half a cubic
+centimeter of phenolphthalien solution added and decinormal barium
+hydroxid solution run in until a red color is produced. The contents
+of the beaker are then returned to the measuring flask to remove any
+acid remaining therein, poured again into the beaker, and the titration
+continued until the red color produced remains apparently unchanged for
+two or three minutes, The number of cubic centimeters of decinormal
+<span class="pagenum"><a id="Page_389"></a>[Pg 389]</span>
+barium hydroxid solution required should be increased by one-tenth to
+represent the entire distillate.</p>
+
+<p>The number thus obtained expresses, in cubic centimeters of decinormal
+alkali solution, the volatile acidity of the sample. In each case
+blank distillations of the reagents used should be conducted under
+identical conditions, especially when alcoholic alkali is used for
+saponification. It is difficult to secure alcohol which will not yield
+a trace of volatile acid in the conditions named. The quantity of
+decinormal alkali required to neutralize the blank distillate is to be
+deducted from that obtained with the sample of fat.</p>
+
+<p id="P_351"><b>351. Determination of Soluble and Insoluble Fat Acids.</b>—The
+volatile fat acids are more or less soluble in water, while those which
+are not distillable in a current of steam are quite insoluble. It is
+advisable, therefore, to separate these two classes of fat acids, and
+the results thus obtained are perhaps more decidedly quantitive than
+are given by the distillation process just described. The methods used
+for determining the percentage of insoluble acids are essentially those
+of Hehner.<a id="FNanchor_320" href="#Footnote_320" class="fnanchor">[320]</a>
+Many variations of the process have been proposed, especially in respect
+of the soluble acids.<a id="FNanchor_321" href="#Footnote_321" class="fnanchor">[321]</a></p>
+
+<p>The process, as conducted in this laboratory and approved by the
+Association of Official Agricultural Chemists, is as follows:</p>
+
+<p><i>Preparation of Reagents.—Sodium Hydroxid Solution.</i>—A
+decinormal solution of sodium hydroxid is used. Each cubic centimeter
+contains 0.0040 gram of sodium hydroxid and neutralizes 0.0088 gram of
+butyric acid (<b>C₄H₈O₂</b>).</p>
+
+<p><i>Alcoholic Potash Solution.</i>—Dissolve forty grams of good caustic
+potash in one liter of ninety-five per cent alcohol redistilled over
+caustic potash or soda. The solution must be clear and the potassium
+hydroxid free from carbonates.</p>
+
+<p><i>Standard Acid Solution.</i>—Prepare accurately a half normal
+solution of hydrochloric acid.</p>
+
+<p><i>Indicator.</i>—Dissolve one gram of phenolphthalien in 100 cubic
+centimeters of ninety-five per cent alcohol.</p>
+
+<p><i>Determination.—Soluble Acids.</i>—About five grams of the sample
+are placed in the saponification flask already described, fifty cubic
+<span class="pagenum"><a id="Page_390"></a>[Pg 390]</span>
+centimeters of the alcoholic potash solution added, the flask stoppered
+and placed in the steam-bath until the fat is entirely saponified. The
+operation may be facilitated by occasional agitation. The alcoholic
+potash is always measured with the same pipette and uniformity further
+secured by allowing it to drain the same length of time (thirty
+seconds). Two or three blank experiments are conducted at the same time.</p>
+
+<p>In from five to thirty minutes, according to the nature of the fat, the
+liquid will appear perfectly homogeneous and, when this is the case,
+the saponification is complete and the flask is removed and cooled.
+When sufficiently cool, the stopper is removed and the contents of
+the flask rinsed with a little ninety-five per cent alcohol into an
+erlenmeyer, of about 200 cubic centimeters capacity, which is placed on
+the steam-bath together with the blanks until the alcohol is evaporated.</p>
+
+<p>The blanks are titrated with half normal hydrochloric acid, using
+phenolphthalien as indicator, and one cubic centimeter more of the half
+normal hydrochloric acid than is required to neutralize the potash in
+the blanks is run into each of the flasks containing the fat acids. The
+flask is connected with a reflux condenser and placed on the steam-bath
+until the separated fat acids form a clear stratum on the upper surface
+of the liquid. The flask and contents are cooled in ice-water.</p>
+
+<p>The fat acids having quite solidified, the liquid contents of the flask
+are poured through a dry filter into a liter flask, taking care not
+to break the cake. Between 200 and 300 cubic centimeters of water are
+brought into the flask, the cork with the condenser reinserted and the
+flask placed on the steam-bath until the cake of acid is thoroughly
+melted. During the melting of the cake of fat acids, the flask should
+occasionally be agitated with a rotary motion in such a way that its
+contents are not made to touch the cork. When the fat acids have again
+separated into an oily layer, the flask and its contents are cooled
+in ice-water and the liquid filtered through the same filter into the
+same liter flask as before. This treatment with hot water, followed
+by cooling and filtration of the wash water, is repeated three times,
+the washings being added to the first filtrate. The mixed washings and
+<span class="pagenum"><a id="Page_391"></a>[Pg 391]</span>
+filtrate are made up to one liter, and 100 cubic centimeters
+thereof in duplicate are titrated with decinormal sodium hydroxid.
+The number of cubic centimeters of sodium hydroxid required for
+each 100 cubic centimeters of the filtrate is multiplied by ten.
+The number so obtained represents the volume of decinormal sodium
+hydroxid neutralized by the soluble fat acids of the fat, plus that
+corresponding to the excess of the standard acid used, <i>viz.</i>, one
+cubic centimeter. The number is therefore to be diminished by five,
+corresponding to the excess of one cubic centimeter of half normal
+acid. This corrected volume multiplied by 0.0088 gives the weight of
+soluble acids as butyric acid in the amount of fat saponified.</p>
+
+<p><i>Insoluble Acids.</i>—The flask containing the cake of insoluble
+fat acids from the above determination and the paper through which the
+soluble fat acids have been filtered are allowed to drain and dry for
+twelve hours, when the cake, together with as much of the fat acids
+as can be removed from the filter paper, is transferred to a weighed
+evaporating dish. The funnel, with the filter, is then placed in an
+erlenmeyer and the paper thoroughly washed with absolute alcohol. The
+flask is rinsed with the washings from the filter paper, then with pure
+alcohol, and the rinsings transferred to the evaporating dish. The dish
+is placed on the steam-bath until the alcohol is evaporated, dried for
+two hours at 100°, cooled in a desiccator and weighed. It is again
+placed in the air-bath for two hours, cooled as before and weighed.
+If there be any considerable decrease in weight, reheat two hours and
+weigh again. The final weighing gives the weight of insoluble fat acids
+in the sample, from which the percentage is easily calculated.</p>
+
+<p>The quantity of non-volatile and insoluble acids in common glycerids
+is from ninety-five to ninety-seven parts in 100. The glycerids yield
+almost the same proportion of fat acids and glycerol when the acids are
+insoluble and have high molecular weights. When the acids are soluble
+and the molecular weight low the proportion of acids decreases and that
+of glycerol increases.</p>
+
+<p>In the following table will be found the data secured by quantitive
+<span class="pagenum"><a id="Page_392"></a>[Pg 392]</span>
+saponification and separation of soluble and insoluble acids found in
+the more common glycerids:<a id="FNanchor_322" href="#Footnote_322" class="fnanchor">[322]</a></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bl bb bt2" colspan="2">&nbsp;</th>
+      <th class="tdc_bott bt2 bl bb" colspan="2">&nbsp;Molecular weight of&nbsp;</th>
+      <th class="tdc bt2 bl br bb" colspan="2">&nbsp;Yield per 100 parts&nbsp;<br>of glycerid.</th>
+    </tr><tr>
+      <th class="tdc bl bb">&nbsp;Glycerid.&nbsp;</th>
+      <th class="tdc bl bb">&nbsp;Fat acid.&nbsp;</th>
+      <th class="tdc bl bb">Glycerid.</th>
+      <th class="tdc bl bb">Fat acid.</th>
+      <th class="tdc bl bb">Fat acid.</th>
+      <th class="tdc bl bb br">Glycerol.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Stearin</td>
+      <td class="tdl_ws1">Stearic</td>
+      <td class="tdc">890</td>
+      <td class="tdc">284</td>
+      <td class="tdc">95.73</td>
+      <td class="tdc">10.34</td>
+   </tr><tr>
+      <td class="tdl">Olein</td>
+      <td class="tdl_ws1">Oleic</td>
+      <td class="tdc">884</td>
+      <td class="tdc">282</td>
+      <td class="tdc">95.70</td>
+      <td class="tdc">10.41</td>
+   </tr><tr>
+      <td class="tdl">Palmitin</td>
+      <td class="tdl_ws1">Palmitic</td>
+      <td class="tdc">806</td>
+      <td class="tdc">256</td>
+      <td class="tdc">95.28</td>
+      <td class="tdc">11.42</td>
+   </tr><tr>
+      <td class="tdl">Myristin</td>
+      <td class="tdl_ws1">Myristic</td>
+      <td class="tdc">722</td>
+      <td class="tdc">228</td>
+      <td class="tdc">94.47</td>
+      <td class="tdc">12.74</td>
+   </tr><tr>
+      <td class="tdl">Laurin</td>
+      <td class="tdl_ws1">Lauric</td>
+      <td class="tdc">638</td>
+      <td class="tdc">200</td>
+      <td class="tdc">94.95</td>
+      <td class="tdc">14.42</td>
+   </tr><tr>
+      <td class="tdl">Caprin</td>
+      <td class="tdl_ws1">Capric</td>
+      <td class="tdc">594</td>
+      <td class="tdc">172</td>
+      <td class="tdc">93.14</td>
+      <td class="tdc">15.48</td>
+   </tr><tr>
+      <td class="tdl">Caproin</td>
+      <td class="tdl_ws1">Caproic</td>
+      <td class="tdc">386</td>
+      <td class="tdc">116</td>
+      <td class="tdc">90.16</td>
+      <td class="tdc">23.83</td>
+   </tr><tr>
+      <td class="tdl">Butyrin</td>
+      <td class="tdl_ws1">Butyric</td>
+      <td class="tdc">302</td>
+      <td class="tdc">&#8199;88</td>
+      <td class="tdc">87.41</td>
+      <td class="tdc">30.46</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The general expression for the saponification of a neutral fat is
+<b>C₃H₅O₃.R₃ + 3H₂O = 3R.OH + C₃H₈O₃</b>, in which R represents the acid
+radicle. It is evident from this that the yield of more than 100 parts
+of fat acids and glycerol given by glycerids is due to the absorption
+of water during the reaction.</p>
+
+<p><b>352. Formulas for General Calculations.</b>—For calculating the
+theoretical yields of fat acids and glycerol, the following general
+formulas may be used:</p>
+
+<ul class="index">
+<li class="isub1">Let&emsp;<i>M</i> = the molecular weight of the fat acid:</li>
+<li class="isub3"><i>K</i> = saponification value:</li>
+<li class="isub3"><i>F</i> = the quantity of free fat acids in the glycerid:</li>
+<li class="isub3"><i>N</i> = the quantity of neutral fat in the glycerid:</li>
+<li class="isub3"><i>A</i> = the number of milligrams of potassium hydroxid required</li>
+<li class="isub5">to saturate the free acid in one gram of the sample.</li>
+<li class="isub1">&nbsp;</li>
+<li class="isub1">The free acid is determined by the method given below.</li>
+</ul>
+
+<p><i>M</i> grams of a fat acid require 56100 milligrams of potassium
+hydroxid for complete neutralization while <i>F</i> grams corresponding
+to 100 grams of fat are saturated by 100 × <i>A</i> milligrams of the alkali.</p>
+
+<p class="f105">Then&emsp;<i>M</i> : 56100 = <i>F</i> : 100<i>A</i>.</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">Whence&emsp;<i>F</i> = &nbsp;</td>
+      <td class="tdc bb"><i>AM</i></td>
+      <td class="tdr" rowspan="2"><span class="ws4">(1).</span></td>
+   </tr><tr>
+      <td class="tdc">561</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Likewise since <i>M</i> grams of fat acid require the quantity of
+potassium hydroxid mentioned above we have:
+<span class="pagenum"><a id="Page_393"></a>[Pg 393]</span></p>
+
+<p class="f105">1 : <i>K</i> = <i>M</i> : 56100,</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">Whence&emsp;<i>M</i> = &nbsp;</td>
+      <td class="tdc bb">56100</td>
+      <td class="tdr" rowspan="2"><span class="ws4">(2).</span></td>
+   </tr><tr>
+      <td class="tdc"><i>K</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Substituting this value of <i>M</i> in (1) we have</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>F</i> = &nbsp;</td>
+      <td class="tdc bb"><i>A</i> × 56100</td>
+      <td class="tdl" rowspan="2">&nbsp; = &nbsp;</td>
+      <td class="tdc bb">100<i>A</i></td>
+      <td class="tdr" rowspan="2"><span class="ws3">(3).</span></td>
+   </tr><tr>
+      <td class="tdc">561 × <i>K</i></td>
+      <td class="tdc">561 × <i>K</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p>It is evident that it is not necessary to calculate the acid value
+(<i>A</i>) of the sample and the saponification value (<i>K</i>) of the
+free fat acids, the ratio <i>A</i>/<i>K</i> alone being required. It
+will be sufficient therefore to substitute for <i>A</i> and <i>K</i>
+the number of cubic centimeters of alkali solutions required for
+one gram of the fat and one gram of the fat acids, respectively. If
+<i>a</i> and <i>b</i> represent these numbers the formula may be written</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>F</i> = &nbsp;</td>
+      <td class="tdc bb">100<i>a</i></td>
+      <td class="tdr" rowspan="2"><span class="ws10">(4);</span></td>
+   </tr><tr>
+      <td class="tdc"><i>b</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">and&emsp;<i>N</i> = 100 - <i>F</i> = &nbsp;</td>
+      <td class="tdc bb">100<i>a</i></td>
+      <td class="tdr" rowspan="2"><span class="ws4">(5).</span></td>
+   </tr><tr>
+      <td class="tdc"><i>b</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p>To simplify the determinations, it may be assumed that the free fat
+acids have the same molecular weight as those still in combination
+with the glycerol in any given sample. On this assumption, the
+process may be carried on by determining the acid value <i>A</i> and
+the saponification value <i>K</i> for the total fat acids. The mean
+molecular weight <i>M</i>, the percentage of free fat acids <i>F</i>,
+and the proportion of neutral fat <i>N</i>, may then be calculated from
+the formulas (2), (3), (4), and (5).</p>
+
+<p>Further, let <i>G</i> = the quantity of glycerol and <i>L</i> that of
+fat acids obtainable from one gram of neutral fat, that is, <span class="fs_120">¹/₁₀₀</span>
+of <i>H</i> the percentage of total fat acids.</p>
+
+<p>The molecular weight of the neutral fat in each case is 3<i>M</i> + 38.
+Therefore, 3<i>M</i> + 38 parts of neutral fat yield 3<i>M</i> parts of
+fat acids and ninety-two parts of glycerol (<b>C₃H₈O₃</b> = 92).</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">Then&emsp;<i>L</i> = &nbsp;</td>
+      <td class="tdc bb"><i>H</i></td>
+      <td class="tdl" rowspan="2">&nbsp; = &nbsp;</td>
+      <td class="tdc bb">3<i>M</i></td>
+      <td class="tdl" rowspan="2"><span class="ws3">(6);</span></td>
+   </tr><tr>
+      <td class="tdc">100</td>
+      <td class="tdc">3<i>M</i> + 38</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">and&emsp;<i>G</i> = &nbsp;</td>
+      <td class="tdc bb">92</td>
+      <td class="tdl" rowspan="2"><span class="ws6">(7).</span></td>
+   </tr><tr>
+      <td class="tdc">3<i>M</i> + 38</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><i>N</i> per cent of neutral fat yields, therefore, on saponification,
+<span class="pagenum"><a id="Page_394"></a>[Pg 394]</span>
+the following theoretical quantities of fat acids <i>F</i>, and
+glycerol <i>G</i> expressed as parts per hundred.</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>F</i> = <i>N</i> ×&nbsp;</td>
+      <td class="tdc bb">3<i>M</i></td>
+      <td class="tdl" rowspan="2"><span class="ws6">(8);</span></td>
+   </tr><tr>
+      <td class="tdc">3<i>M</i> + 38</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">and&emsp;<i>G</i> = <i>N</i> ×&nbsp;</td>
+      <td class="tdc bb">92</td>
+      <td class="tdl" rowspan="2"><span class="ws4">(9).</span></td>
+   </tr><tr>
+      <td class="tdc">3<i>M</i> + 38</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Formula (9) expresses also the total yield of glycerol from any given
+sample. For a further discussion of this part of the subject a work of
+a more technical character may be consulted.<a id="FNanchor_323" href="#Footnote_323" class="fnanchor">[323]</a></p>
+
+<p><b>353. Determination of a Free Fat Acid in a Fat.</b>—The principle
+of the method rests upon the comparative accuracy with which a free fat
+acid can be titrated with a set alkali solution when phenolphthalien
+is used as an indicator. Among the many methods of manipulation which
+the analyst has at his command there is probably none more simple and
+accurate than that depending on the solution of the sample in alcohol,
+ether, chloroform, or carbon tetrachlorid. Any acidity of the solvent
+is determined by separate titration and the proper correction made.
+Either an aqueous or alcoholic solution of the alkali may be used,
+preferably the latter. The alkaline solution may be approximately or
+exactly decinormal, but it is easier to make it approximately so and
+to determine its real value before each operation by titration against
+a standard decinormal solution of acid. About ten grams of the sample
+and fifty cubic centimeters of the solvent will be found convenient
+quantities.</p>
+
+<p><i>Example.</i>—Ten grams of rancid olive oil dissolved in
+alcohol ether require three and eight-tenths cubic centimeters of a
+solution of alcoholic potash to saturate the free acid present. When
+titrated with decinormal acid the potash solution is found to contain
+25.7 milligrams of potassium hydroxid in each cubic centimeter. The
+specific gravity of the oil is 0.917 and the weight used therefore 9.17
+grams. Then the total quantity of potassium hydroxid required for the
+neutralization of the acid is 25.7 × 3.8 = 97.7 milligrams.</p>
+
+<p>The acid value <i>A</i> is therefore:</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>A</i> =&nbsp;</td>
+      <td class="tdc bb">3.8 × 25.7</td>
+      <td class="tdl" rowspan="2">&nbsp;= 10.6</td>
+   </tr><tr>
+      <td class="tdc">9.17</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_395"></a>[Pg 395]</span>
+It is customary to regard free acid as oleic, molecular weight 282. On
+this assumption the percentage of free acids in the above case is found
+by the formula</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>A</i> (per cent) =&nbsp;</td>
+      <td class="tdc bb">3.8 × 25.7 × 282</td>
+      <td class="tdl" rowspan="2">&nbsp;= 5.35</td>
+   </tr><tr>
+      <td class="tdc">561 × 9.17</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>354. Identification of Oils and Fats.</b>—Properly, the methods
+of identifying and isolating the different oils and fats should
+be looked for in works on food adulteration. There are, however,
+many characteristics of these glycerids which can be advantageously
+discussed in a work of this kind. Many cases arise in which the analyst
+is called upon to determine the nature of a fat and discover whether
+it be admixed with other glycerids. It is important often to know in
+a given case whether an oil be of animal or vegetable origin. Many of
+the methods of analysis already described are found useful in such
+discriminations. For instance, a large amount of soluble or volatile
+acids in the sample under examination, would indicate the presence
+of a fat derived from milk while the form of the crystals in a solid
+fat would give a clue to whether it were the product of the ox or the
+swine. In the succeeding paragraphs will be briefly outlined some of
+the more important additional methods of determining the nature and
+origin of fats and oils of which the history is unknown.</p>
+
+<p>The data obtained by means of the methods which have been described,
+both physical and chemical, are all useful in judging the character and
+nature of a glycerid of unknown origin. The colorations produced by
+oxidizing agents, in the manner already set forth will be found useful,
+especially when joined to those obtained with cottonseed and sesame
+oils yet to be described. For instance, the red coloration produced by
+nitric acid of 1.37 specific gravity is regarded by some authorities
+as characteristic of cottonseed oil as well as the reduction by it of
+silver nitrate. The coloration tests with silver nitrate (paragraph
+<b><a href="#P_320">320</a></b>) and with phosphomolydic acid (paragraph <b><a href="#P_318">318</a></b>)
+are also helpful in classifying oils in respect of their animal or
+vegetable origin. The careful consideration of these tests, together
+with a study of the numbers obtained by treating the samples with iodin,
+<span class="pagenum"><a id="Page_396"></a>[Pg 396]</span>
+and the heat of bromination and sulfuric saponification, is commended
+to all who are interested in classifying oils. In addition to these
+reactions a few specific tests are added for more detailed work.</p>
+
+<p><b>355. Consistence.</b>—It has already been said that oils are mostly
+of vegetable origin and the solid fats of animal derivation. In the
+animal economy it would be a source of disturbance to have in the
+tissues a large body of fat which would remain in a liquid state at the
+normal temperature of the body. Nearly all the animal fats are found to
+have a higher melting point than the body containing them. An exception
+is found in the case of butter fat, but it should be remembered that
+this fat is an excretion and not intended for tissue building until
+it has undergone subsequent digestion. Fish oils are another notable
+exception to the rule, but in this case these oils can hardly be
+regarded as true glycerids in the ordinary sense of that term.</p>
+
+<p>In general, it may be said that a sample of a glycerid, which in its
+natural state remains liquid at usual room temperatures, is probably
+an oil of vegetable origin. Fish oils have also an odor and taste
+which prevent them from being confounded with vegetable oils. In oils
+which are manufactured from animal glycerids such as lard oil, the
+discrimination is more difficult but peculiarities of taste and color
+are generally perceptible.</p>
+
+<p><b>356. Nature of the Fat Acid.</b>—When it is not possible to
+discriminate between samples by the sensible physical properties
+just described, much light can be thrown on their origin by the
+determination of their other physical properties, such as specific
+gravity, refractive index, melting point, etc., in the manner already
+fully described. Further light may be furnished by saponification and
+separation of the fat acids. The relative quantities of oleic, stearic,
+palmitic, and other acids will help to a correct judgment in respect
+of the nature of the sample. The vegetable oils and lard oils, for
+instance, consist chiefly of olein; lard and tallow contain a large
+proportion of stearin; palm oil and butter fat contain considerable
+<span class="pagenum"><a id="Page_397"></a>[Pg 397]</span>
+portions of palmitin, and the latter is distinguished moreover by the
+presence of soluble and volatile acids combined as butyrin and its
+associated glycerids.</p>
+
+<p>Oleic acid can be rather readily separated from stearic and palmitic
+by reason of the solubility of its lead salts in ether. One method of
+accomplishing this separation has already been described (paragraph <b><a href="#P_339">339</a></b>).</p>
+
+<p><b>357. Separation with Lime.</b>—A quicker, though perhaps not as
+accurate a separation of the oleic from the palmitic and stearic acids,
+is accomplished by means of lime according to the method developed by
+Bondzyuski and Rufi.<a id="FNanchor_324" href="#Footnote_324" class="fnanchor">[324]</a>
+This process is used chiefly, however, to separate the free fat acids
+(palmitic, stearic) from the neutral fat and the free oleic acid. It
+probably has no point of superiority over the lead process.</p>
+
+<p><b>358. Separation of the Glycerids.</b>—The fact that olein is liquid
+at temperatures allowing palmitin and stearin to remain solid, permits
+of a rough separation of these two classes of bodies by mechanical
+means. The mixed fats are first melted and allowed to cool very slowly.
+In these conditions the stearin and palmitin separate from the olein in
+a crystalline form and the olein is removed by pressure through bags.
+In this way lard is separated into lard oil, consisting chiefly of
+olein, and lard stearin, consisting largely of stearin. Beef (caul) fat
+is in a similar manner separated into a liquid (oleo-oil) and a solid
+(oleo-stearin) portion. It is evident that these separations are only
+approximate, but by repeated fractionations a moderately pure olein or
+stearin may be obtained.</p>
+
+<p><b>359. Separation as Lead Salts.</b>—Muter’s process, with a special
+piece of apparatus, has already been described (<b><a href="#P_339">339</a></b>). For
+general analytical work the special tube may be omitted. In a mixture
+of insoluble free fat acids all are precipitated by lead acetate, and
+the resulting soap may be extracted with ether, either with successive
+shakings or in a continuous extraction apparatus. In this latter case
+a little of the lead stearate or palmitate may pass into solution in
+the hot ether and afterwards separate on cooling. When the operation
+is conducted on from two to three grams of the dry mixed acids, the
+percentage proportions of the soluble and insoluble acids (in ether)
+<span class="pagenum"><a id="Page_398"></a>[Pg 398]</span>
+can be determined. The lead salt which passes into solution can be
+decomposed and the oleic acid removed, dried and weighed. Dilute
+hydrochloric acid is a suitable reagent for decomposing the lead soap.
+The difference between the weight of the oleic acid and that of the
+mixed acids before conversion into lead soap furnishes the basis for
+the calculation. For further details in respect of the fat acids the
+reader may consult special analytical works.<a id="FNanchor_325" href="#Footnote_325" class="fnanchor">[325]</a></p>
+
+<p><b>360. Separation of Arachidic Acid.</b>—Peanut oil is easily
+distinguished from other vegetable glycerids by the presence of
+arachidic acid.</p>
+
+<p>The method used in this laboratory for separating arachidic acid is
+a modification of the usual methods based on the process as carried
+out by Milliau.<a id="FNanchor_326" href="#Footnote_326" class="fnanchor">[326]</a>
+About twenty grams of the oil are saponified with alcoholic soda, using
+twenty cubic centimeters of 36° baumé soda solution diluted with 100
+cubic centimeters of ninety per cent alcohol. When the saponification
+is complete, the soda is converted into the lead soap by treatment with
+a slight excess of a saturated alcoholic solution of lead acetate. Good
+results are also obtained by using dilute alcohol, <i>viz.</i>, fifty
+per cent, instead of ninety per cent, in preparing the lead acetate solution.</p>
+
+<p>While still warm the supernatant liquid is decanted, the precipitate
+washed by decantation with warm ninety per cent alcohol and triturated
+with ether in a mortar four times, decanting the ethereal solution in
+each instance. By this treatment all of the lead oleate and hypogaeate
+are removed and are found in the ethereal solution, from which they can
+be recovered and the acids set free by hydrochloric acid and determined
+in the usual way.</p>
+
+<p>The residue is transferred to a large dish containing two or three
+liters of pure water and decomposed by the addition of about fifty
+cubic centimeters of strong hydrochloric acid. The lead chlorid formed
+is soluble in the large quantity of water present, which should be
+warm enough to keep the free acids in a liquid state in which form
+they float as a clear oily liquid on the surface. The free acids are
+decanted and washed with warm water to remove the last traces of lead
+<span class="pagenum"><a id="Page_399"></a>[Pg 399]</span>
+chlorid and hydrochloric acid. The last traces of water are removed
+by drying in a thin layer in vacuo. Practically all of the acids,
+originally present in the sample except oleic and hypogaeic, are thus
+obtained in a free state and their weight is determined.</p>
+
+<p>The arachidic acid may be separated almost quantitively by dissolving
+the mixed acids in forty cubic centimeters of ninety per cent alcohol,
+adding a drop of hydrochloric acid, cooling to 16° and allowing to
+stand until the arachidic acid has crystallized. The crystals are
+purified by washing twice with twenty cubic centimeters of ninety
+per cent and three times with the same quantity of seventy per cent
+alcohol. The residual impure arachidic acid is dissolved in boiling
+absolute alcohol, poured through a filter and washed with pure hot
+alcohol. The filtrate is evaporated to dryness and heated to 100° until
+a constant weight is obtained. From the above data, the percentages of
+oleic, hypogaeic, arachidic and other acids in the sample examined are
+calculated.</p>
+
+<p>In the above process, owing to the pasty state of the lead soaps, the
+trituration in a mortar with ether is found troublesome. The extraction
+of the lead oleate and hypogaeate is facilitated by throwing the pasty
+ethereal mass on a filter and washing it thoroughly with successive
+portions of about fifty cubic centimeters of ether. By this variation,
+it was found by Krug in this laboratory, that less ether was required
+and a more complete removal of the lead oleate effected. The solution
+of the lead oleate is completed by about half a dozen washings with
+ether as above described. The extraction may also be secured by
+placing the lead soaps in a large extracting apparatus and proceeding
+as directed in paragraph <b><a href="#P_40">40</a></b>. The residue is washed from the
+filter paper into a large porcelain dish and decomposed as already
+described with hydrochloric acid. After the separation is complete, the
+mixture is cooled until the acids are solid. The solid acids are then
+transferred to a smaller dish, freed of water and dissolved in ether.
+The ethereal solution is washed with water to remove any traces of
+lead salt or of hydrochloric acid. After the removal of the ether, the
+arachidic acid is separated as has already been described.
+<span class="pagenum"><a id="Page_400"></a>[Pg 400]</span></p>
+
+<p>The melting point of pure arachidic acid varies from 73° to 75°.</p>
+
+<p><b>361. Detection of Arachis</b> (<b>Peanut</b>) <b>Oil.</b>—Kreis
+has modified the usual process of Renard for the detection of arachis
+oil, by precipitating the solution of the fat acid with an alcoholic
+instead of an aqueous solution of lead acetate, in a manner quite
+similar to that described above.<a id="FNanchor_327" href="#Footnote_327" class="fnanchor">[327]</a>
+The fat acids are obtained in the usual manner, washed with hot water
+and the acids from twenty grams of the oil dissolved in 100 cubic
+centimeters of ninety per cent alcohol. The solution is cooled in
+ice-water and the fat acids precipitated by the addition of fifteen
+grams of lead acetate dissolved in 150 cubic centimeters of ninety
+per cent alcohol. The precipitate, after standing for two hours, is
+separated by filtration through cotton wool and is extracted for six
+hours with ether. The residue is boiled with 250 cubic centimeters of
+five per cent hydrochloric acid until the fat acids appear as a clear
+oily layer upon the surface. The acids thus obtained are washed with
+hot water to remove lead chlorid, dried by pressing between blotting
+paper, dissolved in 100 cubic centimeters of ninety per cent alcohol,
+cooled to 15° and allowed to stand for several hours, after which
+time any arachidic acid present is separated by crystallization and
+identified in the usual manner.</p>
+
+<p>When it is not important to obtain all of the acid present, the process
+may be simplified in the following manner:</p>
+
+<p>The fat acids obtained from twenty grams of oil are dissolved in 300
+cubic centimeters of ether and treated at the temperature of ice-water
+with a quantity of the alcoholic lead acetate solution mentioned above.
+Lead oleate remains in solution and the precipitate which forms after
+a few hours consists almost wholly of the lead salts of the solid fat
+acids. The precipitate is collected, washed with ether and identified
+in the usual manner.</p>
+
+<p><b>362. Cottonseed Oil, Bechi’s Test.</b>—Crude, fresh cottonseed oil,
+when not too highly colored, and generally the refined article, may be
+distinguished from other oils by the property of reducing silver salts
+<span class="pagenum"><a id="Page_401"></a>[Pg 401]</span>
+in certain conditions. The reaction was first noticed by Bechi and has
+been the subject of extensive discussions.<a id="FNanchor_328" href="#Footnote_328" class="fnanchor">[328]</a></p>
+
+<p>The process as proposed by Bechi has been modified in many ways but
+apparently without improving it. It is conducted as follows: One gram
+of silver nitrate is dissolved in 200 cubic centimeters of ninety-eight
+per cent alcohol and forty cubic centimeters of ether and one drop of
+nitric acid added to the mixture. Ten cubic centimeters of the oil
+are shaken in a test tube with one cubic centimeter of this reagent,
+and then with ten cubic centimeters of a mixture containing 100
+cubic centimeters of amyl alcohol and ten of colza oil. The mixture
+is divided into two portions, one of which is put aside for future
+comparison and the other plunged into boiling water for fifteen
+minutes. A deep brown or black color, due to the reduction of silver,
+reveals the presence of cottonseed oil.</p>
+
+<p>In this laboratory the heating is accomplished in a small porcelain
+dish on which is often deposited a brilliant mirror of metallic silver.
+The white color of the porcelain also serves as a background for the
+observation of the coloration produced. In most instances a green color
+has been noticed after the reduction of the silver is practically
+complete. Unless cottonseed oil has been boiled or refined in some
+unusual way, the test, as applied above, is rarely negative. The
+reduction of the silver is doubtless due to some aldehydic principle,
+present in extremely minute quantities, and which may be removed by
+some methods of technical treatment. The silver nitrate test therefore
+is reliable when the reduction takes place, but the absence of a distinct
+reaction may not in all cases prove the absence of cottonseed oil.</p>
+
+<p><b>363. Milliau’s Process.</b>—Milliau has proposed the application
+of the silver salt directly to the free fat acids of the oil instead
+of to the oil itself.<a id="FNanchor_329" href="#Footnote_329" class="fnanchor">[329]</a>
+About fifteen cubic centimeters of the oil are saponified with
+alcoholic potash in the usual manner, 150 cubic centimeters of
+water added to the dish and the mixture boiled until the alcohol is
+evaporated. The fat acids are freed by the addition of decinormal
+sulfuric acid and as they rise to the surface in a pasty condition are
+removed with a spoon. The free acids are washed with distilled water.
+<span class="pagenum"><a id="Page_402"></a>[Pg 402]</span>
+The water is drained off and the free acids dissolved in fifteen
+cubic centimeters of ninety-two per cent alcohol and two cubic
+centimeters of a three per cent solution of silver nitrate. The test
+tube containing the mixture is well shaken and placed in a water-bath,
+out of contact with light, and left until about one-third of the
+alcohol is evaporated. Ten cubic centimeters of water are added, the
+heating continued for a few minutes and the color of the supernatant
+fat acids observed. The presence of cottonseed oil is revealed by the
+production of a lustrous precipitate which colors the fat acids black.
+In some cases the process of Milliau gives better results than the
+original method of Bechi, but this is not always the case. It does
+away with the use of amyl alcohol and colza oil, but its manipulation is
+more difficult. In all doubtful cases the analyst should apply both methods.</p>
+
+<p><b>364. Detection of Sesame Oil.</b>—Milliau has pointed out a
+characteristic reaction of this oil which may be used with advantage
+in cases of doubtful identity.<a id="FNanchor_330" href="#Footnote_330" class="fnanchor">[330]</a>
+The identification is based on the fact that the free acids of sesame
+oil, or some concomitant thereof, give a rose-red color when brought in
+contact with a solution of sugar in hydrochloric acid.</p>
+
+<p>The analytical process is conducted as follows: About fifteen grams
+of the oil are saponified with alcoholic soda and when the reaction
+is complete treated with 200 cubic centimeters of hot water and
+boiled until the alcohol is removed. The fat acids are set free with
+decinormal sulfuric acid and removed with a spoon as they rise to the
+surface in a pasty state, in which condition they are washed by shaking
+with water in a large test tube. When washed, the acids are placed in
+an oven at 105° until the greater part of the water is evaporated and
+the acids begin to become fluid. At this point they are treated with
+half their volume of hydrochloric acid saturated with finely ground
+sugar. On shaking the mixture, a rose color is developed which is
+characteristic of the sesame oil. Other oils give either no coloration
+or at most a yellow tint.</p>
+
+<p><b>365. The Sulfur Chlorid Reaction.</b>—Some vegetable oils, when
+treated with sulfur chlorid, give a hard product similar to elaidin,
+while lard does not. This reaction is therefore helpful in
+<span class="pagenum"><a id="Page_403"></a>[Pg 403]</span>
+discriminating between some vegetable and animal glycerids. The process
+which is described by Warren has been used with some satisfaction in
+this laboratory.<a id="FNanchor_331" href="#Footnote_331" class="fnanchor">[331]</a></p>
+
+<p>Five grams of the oil or fat are placed in a tared porcelain dish and
+treated with two cubic centimeters of carbon bisulfid and the same
+quantity of sulfur chlorid. The dish is placed on a steam-bath and its
+contents stirred until the reaction is well under way. The heating is
+continued until all volatile products are evaporated, the hard mass
+being well rubbed up to facilitate the escape of imprisoned vapors.
+The powdered or pasty mass is transferred to a filter and washed with
+carbon bisulfid to remove all unaltered oil. The washing with carbon
+bisulfid is hastened by pressure and about 200 cubic centimeters of the
+solvent should be used. After drying, the weight of insoluble matter is
+obtained and deducted from the total weight of the sample used.</p>
+
+<p>The color and tenacity of the hard, insoluble portion are
+characteristic. The quantitive part of the operation appears to have
+but little value, but applied qualitively in this laboratory it
+produces hard, leathery masses with cotton, olive and peanut oils,
+and but little change in lard and beef fats. Qualitively applied,
+the process is conducted as described above but without making the
+weighings. In this instance it is as easy of application as the process
+of Bechi and is deserving of greater attention than has been given it
+by analysts.</p>
+
+<p>In the combination which takes place between the sulfur and the fat it
+is probable that only addition products are formed, since the quantity
+of alkali required for saponification is not diminished by previously
+treating the fat with sulfur chlorid.<a id="FNanchor_332" href="#Footnote_332" class="fnanchor">[332]</a>
+The reactions which take place are probably well represented by the
+following equations, in which oleic acid is treated with sulfur chlorid:</p>
+
+<p class="f105">C₁₈H₃₄O₂ + S = C₁₈H₃₄S.O₂. &nbsp;<br>
+C₁₈H₃₄S.O₂ + NaOH = C₁₈H₃₄SO₂Na + H₂O.</p>
+
+<p><b>366. Detection of Cholesterin and Phytosterin in
+Glycerids.</b>—Cholesterin is often found in animal glycerids and a
+corresponding body, phytosterin, is sometimes found in oils of a
+<span class="pagenum"><a id="Page_404"></a>[Pg 404]</span>
+vegetable origin.<a id="FNanchor_333" href="#Footnote_333" class="fnanchor">[333]</a>
+When one of these two bodies is present it may be useful in
+distinguishing between animal and vegetable glycerids. They are
+detected as follows: Fifty grams of the glycerids in each case are
+saponified with alcoholic alkali, preferably potash, in order to have a
+soft soap. After saponification is complete, the alcohol is evaporated
+and the residual soap dissolved in two liters of water. The mixture
+is shaken with ether and the ethereal solution evaporated to a small
+bulk. The residue, which may contain a small quantity of unsaponified
+fat, is again treated with alcoholic potash and subjected a second
+time to the action of ether, as indicated above, with the addition of
+a few drops of water and of alcohol if the emulsion separate slowly.
+The ethereal extract finally secured is allowed to evaporate slowly
+and the cholesterin (phytosterin) is obtained in a crystalline form.
+The melting point of the cholesterin crystals is 146° and that of the
+phytosterin 132°.</p>
+
+<p>Cholesterin crystallizes in thin rhombic tables while phytosterin
+separates in stellar aggregates or in bundles of long needles.</p>
+
+<p>When dissolved in chloroform the two products show different color
+reactions with sulfuric acid, cholesterin giving a cherry and
+phytosterin a blue-red tint. In a mixture of animal and vegetable
+glycerids the two products are obtained together and the melting point
+of the mixture may afford some idea of the relative quantities of each
+present. It is evident, however, that no reliable judgment can be
+formed from these data of the relative proportions of the two kinds of
+glycerids in the original sample.</p>
+
+<p><b>367. Cholesterin and Paraffin in Ether Extracts.</b>—In ethereal
+extracts of some bodies, especially of flowers of the chrysanthemum,
+paraffin is found combined with cholesterin. The two bodies may be
+separated as follows:<a id="FNanchor_334" href="#Footnote_334" class="fnanchor">[334]</a></p>
+
+<p>The ether extract is treated with aqueous then with alcoholic potash
+several times; the residue soluble in ether is a solid body melting at
+from 70° to 100°.</p>
+
+<p>If the ethereal solution be cooled in a mixture of snow and salt, a
+crystalline deposit is formed. This substance, purified by repeated
+<span class="pagenum"><a id="Page_405"></a>[Pg 405]</span>
+precipitations, is obtained colorless in fine crystalline scales
+melting at 64°. It is very soluble in ether, benzene and chloroform,
+almost insoluble in cold alcohol, and somewhat soluble in hot.</p>
+
+<p>Its percentage composition is:</p>
+
+<table class="spb1 fs_90">
+   <tbody><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdr">Per cent.</td>
+   </tr><tr>
+      <td class="tdl">Carbon<span class="ws3">&nbsp;</span></td>
+      <td class="tdc">85.00</td>
+   </tr><tr>
+      <td class="tdl">Hydrogen</td>
+      <td class="tdc">14.95</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>It is therefore a paraffin.</p>
+
+<p>The ethereal solution, freed by the above process from paraffin, leaves
+on evaporation a crystalline mass which is cholesterin, retaining
+still a small quantity of fat matters. In treating the crystals with
+alcoholic potash these fat bodies are saponified and the residue is
+taken up with ether. The cholesterin is obtained in fine needles
+melting at from 170° to 176°. It presents all the reactions of
+cholesterin, especially the characteristic reaction with chloroform and
+sulfuric acid.</p>
+
+<p><b>368. Absorption of Oxygen.</b>—Among oils a distinction is made
+between those which oxidize readily and those which are of a more
+stable composition. Linseed oil, for instance, in presence of certain
+metallic oxids, absorbs oxygen readily and is a type of the drying
+oils, while olive oil represents the opposite type.</p>
+
+<p>The method of determining the quantity of oxygen absorbed is due to
+Livache and is carried out as follows:<a id="FNanchor_335" href="#Footnote_335" class="fnanchor">[335]</a></p>
+
+<p>Precipitated metallic lead (by zinc) is mixed in a flat dish, with
+the oil to be tested, in the proportions of one gram of lead to
+three-quarters of a gram of oil, and exposed to the air and light of
+the workroom. The dish is weighed from time to time until there is no
+longer any increase in weight.</p>
+
+<p>Instead of lead, finely divided copper has been used by Krug in this
+laboratory, but the percentage of absorption of oxygen is not so
+high with copper as with lead. Krug found the quantities of oxygen
+absorbed, after nine days, by the samples treated with copper and lead
+respectively to be the following:
+<span class="pagenum"><a id="Page_406"></a>[Pg 406]</span></p>
+
+<table class="spb1">
+   <tbody><tr class="fs_90">
+      <td class="tdl">&nbsp;</td>
+      <td class="tdc">Copper, per cent<br>&nbsp; oxygen absorbed. &nbsp;</td>
+      <td class="tdc">Lead, per cent<br>&nbsp; oxygen absorbed. &nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Olive oil</td>
+      <td class="tdc">1.69</td>
+      <td class="tdc">2.03</td>
+   </tr><tr>
+      <td class="tdl">Cottonseed oil</td>
+      <td class="tdc">4.25</td>
+      <td class="tdc">5.30</td>
+   </tr><tr>
+      <td class="tdl">Peanut oil</td>
+      <td class="tdc">2.74</td>
+      <td class="tdc">3.87</td>
+   </tr><tr>
+      <td class="tdl">Linseed oil</td>
+      <td class="tdc">5.55</td>
+      <td class="tdc">7.32</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Livache found that linseed oil absorbed about twice as much oxygen as
+indicated by the data just given.</p>
+
+<p><b>369. Elaidin Reactions.</b>—In discriminating between oils and fats
+having a preponderance of olein and others with a smaller proportion of
+that glycerid, the conversion of the olein into its isomer elaidin is
+of diagnostic value. The following will be found a convenient method of
+applying this test:<a id="FNanchor_336" href="#Footnote_336" class="fnanchor">[336]</a></p>
+
+<p>About ten cubic centimeters of the oil are placed in a test tube
+together with half that quantity of nitric acid and one gram of
+mercury. The mixture is shaken until the mercury dissolves when the
+mass is allowed to remain at rest for twenty minutes. At the end of
+this time it is again shaken and placed aside. In from one to three
+hours the reaction is complete. Olive, peanut and lard oils give
+very hard elaidins. The depth to which a plunger of given weight and
+dimensions sinks into an elaidin mixture at a given temperature, has
+been used as a measure of the percentage of olein contained in the
+sample of oil, but it is evident that such a determination is only
+roughly approximate. Copper may be used instead of mercury for the
+generation of the oxids of nitrogen, but it is not so effective. The
+vapors of nitric oxids may also be conducted directly into the oil
+from a convenient generator. The reaction may also be accomplished
+by shaking the oil with nitric acid and adding, a drop at a time, a
+solution of potassium nitrite.</p>
+
+<h3>AUTHORITIES CITED IN PART FOURTH.</h3>
+<div class="footnotes">
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_229" href="#FNanchor_229" class="label">[229]</a>
+Benedikt and Lewkowitsch; Oils, Fats, Waxes, p. 1.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_230" href="#FNanchor_230" class="label">[230]</a>
+Op. cit. supra, p. 46.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_231" href="#FNanchor_231" class="label">[231]</a>
+Archiv für Physiologie, 1895, Band 61, S. 341:
+Chemiker-Zeitung Repertorium, Band 16, S. 338.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_232" href="#FNanchor_232" class="label">[232]</a>
+Vid. op. cit. 1, p. 63.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_233" href="#FNanchor_233" class="label">[233]</a>
+Bulletin No. 46, Division of Chemistry, U. S. Department of Agriculture, p. 25.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_407"></a>[Pg 407]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_234" href="#FNanchor_234" class="label">[234]</a>
+Journal of the Society of Chemical Industry, 1886, p. 508.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_235" href="#FNanchor_235" class="label">[235]</a>
+Bulletin No. 13, Division of Chemistry, U. S. Department of Agriculture, p. 423.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_236" href="#FNanchor_236" class="label">[236]</a>
+Vid. op. cit. supra, p. 435.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_237" href="#FNanchor_237" class="label">[237]</a>
+Vid. op. cit. supra, p. 437.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_238" href="#FNanchor_238" class="label">[238]</a>
+Vid. op. et loc. cit. supra.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_239" href="#FNanchor_239" class="label">[239]</a>
+Benedikt and Lewkowitsch; Oils, Fats, and Waxes, pp. 96
+et seq.: Zune; Analyse des Beurres, pp. 26 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_240" href="#FNanchor_240" class="label">[240]</a>
+Journal of the Society of Chemical Industry, 1885, p. 535.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_241" href="#FNanchor_241" class="label">[241]</a>
+Vid. op. cit. 1, p. 97.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_242" href="#FNanchor_242" class="label">[242]</a>
+Vid. op. cit. 7, p. 443.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_243" href="#FNanchor_243" class="label">[243]</a>
+Vid. op. cit. 1, pp. 97 and 98.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_244" href="#FNanchor_244" class="label">[244]</a>
+Butter, its Analysis and Adulterations, p. 24.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_245" href="#FNanchor_245" class="label">[245]</a>
+Bulletin No. 46, Division of Chemistry, U. S. Department of Agriculture, p. 34.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_246" href="#FNanchor_246" class="label">[246]</a>
+Vid. op. cit. 7, p. 447.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_247" href="#FNanchor_247" class="label">[247]</a>
+Analyse des Beurres, pp. 33 et 63: Zeitschrift für Instrumentenkunde,
+1887, Ss. 16, 55, 392, 444: Zeitschrift für physikalische Chemie, Band
+18, S. 294. (Ou. pp. 328-9 and 334 read Amagat for Armagat.)</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_248" href="#FNanchor_248" class="label">[248]</a>
+Zeitschrift für physikalische Chemie, Band 18, S. 294.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_249" href="#FNanchor_249" class="label">[249]</a>
+American Chemical Journal, Vol. 10, p. 392.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_250" href="#FNanchor_250" class="label">[250]</a>
+Vid. op. cit. 7, pp. 473 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_251" href="#FNanchor_251" class="label">[251]</a>
+Jean; Chimie Analytique des Matiéres Grasses, p. 26.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_252" href="#FNanchor_252" class="label">[252]</a>
+Vid. op. cit. supra, p. 31.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_253" href="#FNanchor_253" class="label">[253]</a>
+The Analyst, Vol. 20, p. 135.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_254" href="#FNanchor_254" class="label">[254]</a>
+Schlussbericht über die Butteruntersuchungsfrage,
+Milchwirthschaftlicher Verein, Korrespondenzblatt, No. 39, 1891, S. 15.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_255" href="#FNanchor_255" class="label">[255]</a>
+Vid. op. cit. 7, p. 75.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_256" href="#FNanchor_256" class="label">[256]</a>
+Journal of the American Chemical Society, Vol. 15, p. 173.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_257" href="#FNanchor_257" class="label">[257]</a>
+Communicated by Krug to author.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_258" href="#FNanchor_258" class="label">[258]</a>
+Vid. op. cit. 7, pp. 449 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_259" href="#FNanchor_259" class="label">[259]</a>
+Vid. op. cit. 28, Vol. 18, p. 189.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_260" href="#FNanchor_260" class="label">[260]</a>
+Vid. op. cit. 7, Plates 32 and 35.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_261" href="#FNanchor_261" class="label">[261]</a>
+Vid. op. cit. supra, p. 452.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_262" href="#FNanchor_262" class="label">[262]</a>
+Vid. op. cit. supra., p. 93.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_263" href="#FNanchor_263" class="label">[263]</a>
+Vogel; Practische Spectralanalyse, S. 279: Zune; Analyse
+des Beurres, Tome 2, p. 48: Benedikt and Lewkowitsch; Oils,
+Fats, Waxes, p. 83.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_264" href="#FNanchor_264" class="label">[264]</a>
+Bulletin de l’Association Belge des Chimistes, Tome 9, p. 145.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_265" href="#FNanchor_265" class="label">[265]</a>
+Journal of the Chemical Society, Abstracts, Vol. 46, p. 1078:
+Dingler’s Polytechnisches Journal, Band 252, S. 296.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_266" href="#FNanchor_266" class="label">[266]</a>
+The Analyst, July 1894, p. 152.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_267" href="#FNanchor_267" class="label">[267]</a>
+Rapport sur les Procédé pour reconnâitre les
+Falsifications des Huiles d’Olive, p. 37.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_268" href="#FNanchor_268" class="label">[268]</a>
+Vid. op. cit. 7, p. 251.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_408"></a>[Pg 408]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_269" href="#FNanchor_269" class="label">[269]</a>
+Taylor; Annual Report U. S. Department of Agriculture, 1877, p. 622:
+Milliau; Journal of the American Chemical Society, Vol. 15, p. 153.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_270" href="#FNanchor_270" class="label">[270]</a>
+Gantter; Zeitschrift für analytische Chemie, 1893, Band 32, S. 303.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_271" href="#FNanchor_271" class="label">[271]</a>
+Welmans; Journal of the Society of Chemical Industry, 1892, p. 548.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_272" href="#FNanchor_272" class="label">[272]</a>
+Vid. op. cit. 1, p. 254.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_273" href="#FNanchor_273" class="label">[273]</a>
+Pharmaceutische Zeitung, 1891, p. 798: The Analyst, Vol. 17, p. 59.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_274" href="#FNanchor_274" class="label">[274]</a>
+Comptes rendus, Tome 112, p. 105.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_275" href="#FNanchor_275" class="label">[275]</a>
+Pearmain and Moor; The Analyst, Vol. 20, p. 174.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_276" href="#FNanchor_276" class="label">[276]</a>
+Pharmaceutische Zeitschrift für Russland, 1888, S. 721:
+American Journal of Pharmacy, 1889, p. 23.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_277" href="#FNanchor_277" class="label">[277]</a>
+Vid. op. cit. 7, p. 502.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_278" href="#FNanchor_278" class="label">[278]</a>
+Muir; Elements of Thermal Chemistry, p. 25 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_279" href="#FNanchor_279" class="label">[279]</a>
+Comptes rendus, Tome 35 (1852), p. 572.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_280" href="#FNanchor_280" class="label">[280]</a>
+Allen; Commercial Organic Analysis, Vol. 2, p. 56.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_281" href="#FNanchor_281" class="label">[281]</a>
+Vid. op. cit. 1, p. 235; et op. cit. 23, p. 217.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_282" href="#FNanchor_282" class="label">[282]</a>
+Vid. op. cit. 7, p. 44.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_283" href="#FNanchor_283" class="label">[283]</a>
+Vid. op. cit. supra, p. 445: Proceedings American Public
+Health Association, Vol. 10.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_284" href="#FNanchor_284" class="label">[284]</a>
+Vid. op. cit. 23, p. 61.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_285" href="#FNanchor_285" class="label">[285]</a>
+Journal of the Society of Chemical Industry, 1891, p. 234.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_286" href="#FNanchor_286" class="label">[286]</a>
+Vid. op. cit. 1, p. 240.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_287" href="#FNanchor_287" class="label">[287]</a>
+The Analyst, Vol. 22, p. 58.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_288" href="#FNanchor_288" class="label">[288]</a>
+Vid. op. cit. supra, Vol. 20, p. 146.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_289" href="#FNanchor_289" class="label">[289]</a>
+Journal of the American Chemical Society, Vol. 17, p. 378.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_290" href="#FNanchor_290" class="label">[290]</a>
+Dingler’s Polytechnisches Journal, 1884, Ss. 253-281:
+Journal of the Society of Chemical Industry, 1884, p. 641.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_291" href="#FNanchor_291" class="label">[291]</a>
+Bulletin No. 46, Division of Chemistry, U. S. Department of Agriculture, p. 32.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_292" href="#FNanchor_292" class="label">[292]</a>
+Liebermann; Berichte der deutschen chemischen
+Gessellschaft, Band 24, S. 4117.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_293" href="#FNanchor_293" class="label">[293]</a>
+Vid. op. cit. 1, p. 136.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_294" href="#FNanchor_294" class="label">[294]</a>
+Vid. op. cit. 57, 1895, pp. 130 and 1030.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_295" href="#FNanchor_295" class="label">[295]</a>
+Zeitschrift für analytische Chemie, Band 32, Ss. 181 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_296" href="#FNanchor_296" class="label">[296]</a>
+Vid. op. cit. 61, Vol. 16, p. 372.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_297" href="#FNanchor_297" class="label">[297]</a>
+Zeitschrift für angewandte Chemie, 1895, S. 254.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_298" href="#FNanchor_298" class="label">[298]</a>
+Chemiker-Zeitung, Band 19, Ss. 1786 and 1831.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_299" href="#FNanchor_299" class="label">[299]</a>
+Vid. op. cit. 61, Vol. 16, p. 277.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_300" href="#FNanchor_300" class="label">[300]</a>
+Pharmaceutical Journal, Sept. 25, 1880.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_301" href="#FNanchor_301" class="label">[301]</a>
+Vid. op. cit. 59, Vol. 20, p. 50.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_302" href="#FNanchor_302" class="label">[302]</a>
+Williams; vid. op. cit. supra, Vol. 20, p. 277.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_303" href="#FNanchor_303" class="label">[303]</a>
+Vid. op. cit. 59, 1889, p. 61.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_304" href="#FNanchor_304" class="label">[304]</a>
+Vid. op. cit. 61, Vol. 15, p. 110.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_305" href="#FNanchor_305" class="label">[305]</a>
+ Zeitschrift für physiologische Chemie, Band 14, S. 599;
+Band 12, S. 321; Band 16, S. 152.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_409"></a>[Pg 409]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_306" href="#FNanchor_306" class="label">[306]</a>
+Vid. op. cit. 1, p. 60.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_307" href="#FNanchor_307" class="label">[307]</a>
+Vid. op. cit. supra, p. 557.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_308" href="#FNanchor_308" class="label">[308]</a>
+Vid. op. cit. 7, p. 459; vid. op. cit. 63, p. 27.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_309" href="#FNanchor_309" class="label">[309]</a>
+Vid. op. cit. 69, 1895, S. 721.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_310" href="#FNanchor_310" class="label">[310]</a>
+Vid. op. cit. 67, Band 18, S. 199: vid. op. cit. 7, pp. 58-461:
+vid. op. cit. 63, p. 30.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_311" href="#FNanchor_311" class="label">[311]</a>
+Vid. op. cit. 52, p. 40.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_312" href="#FNanchor_312" class="label">[312]</a>
+Vid. op. cit. 1, p. 119.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_313" href="#FNanchor_313" class="label">[313]</a>
+Vid. op. cit. supra, p. 127.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_314" href="#FNanchor_314" class="label">[314]</a>
+Monatshefte für Chemie und verwandte Theile anderer
+Wissenschaften, Band 8, S. 40.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_315" href="#FNanchor_315" class="label">[315]</a>
+Vid. op. cit. 57, 1890, p. 846.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_316" href="#FNanchor_316" class="label">[316]</a>
+Reichert; vid. op. cit. 67, Band 18, S. 68.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_317" href="#FNanchor_317" class="label">[317]</a>
+Meissl; vid. op. cit. 62, Band 233, S. 229.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_318" href="#FNanchor_318" class="label">[318]</a>
+Vid. op. cit. 1, p. 121.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_319" href="#FNanchor_319" class="label">[319]</a>
+Vid. op. cit. 63, p. 28.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_320" href="#FNanchor_320" class="label">[320]</a>
+Vid. op. cit. 67, Band 16, S. 145; Band 18, S. 68: vid.
+op. cit. 7, p. 53: vid. op. cit. 59, 1877, p. 147.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_321" href="#FNanchor_321" class="label">[321]</a>
+Vid. op. cit. 57, 1888, pp. 526 and 697: American
+Chemical Journal, Vol. 10, p. 326: vid. op. cit. 1, pp. 123-127.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_322" href="#FNanchor_322" class="label">[322]</a>
+Vid. op. cit. 1, p. 143.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_323" href="#FNanchor_323" class="label">[323]</a>
+Vid. op. ch. 7, p. 143.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_324" href="#FNanchor_324" class="label">[324]</a>
+Vid. op. cit. 67, 1890, S. 4.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_325" href="#FNanchor_325" class="label">[325]</a>
+Allen; Commercial Organic Analysis, Vol. 2, pp. 224-236.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_326" href="#FNanchor_326" class="label">[326]</a>
+Analyse Chimique des Matiéres Grasses, p. 13.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_327" href="#FNanchor_327" class="label">[327]</a>
+Chemiker-Zeitung, Band 19, S. 451.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_328" href="#FNanchor_328" class="label">[328]</a>
+Annali del Laboratorio Chimico, 1891-92, p. 197:
+Bulletin No. 13, Division of Chemistry, U. S. Department of
+Agriculture, p. 465: Journal of Analytical and Applied Chemistry, Vol.
+1, p. 449; Vol. 2, pp. 119 and 275; vid. op. cit. 311.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_329" href="#FNanchor_329" class="label">[329]</a>
+Rapport presenté a l’Academie Sciences le 20 fevrier,
+1883: Analyse des Matiéres Grasses, p. 17: Bulletin No. 13, Division of
+Chemistry, U. S. Department of Agriculture, p. 446.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_330" href="#FNanchor_330" class="label">[330]</a>
+Analyse des Matiéres Grasses, p. 15.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_331" href="#FNanchor_331" class="label">[331]</a>
+Chemical News, 1888, p. 113: Bulletin No. 13, Division
+of Chemistry, U. S. Department of Agriculture, p. 468.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_332" href="#FNanchor_332" class="label">[332]</a>
+Vid. op. cit. 69, 1895, S. 535.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_333" href="#FNanchor_333" class="label">[333]</a>
+Justus Liebig’s Annalen der Chemie, Band 192, S. 178:
+vid. op. cit. 67, Band 26, S. 575: vid. op. cit. 7, p. 514.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_334" href="#FNanchor_334" class="label">[334]</a>
+Journal de Pharmacie et de Chimie, 1889, p. 447.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_335" href="#FNanchor_335" class="label">[335]</a>
+Moniteur Scientifique, Tome 13, p. 263: vid. op. cit. 69, 1884, S. 262.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_336" href="#FNanchor_336" class="label">[336]</a>
+Vid. op. cit. 7, p. 515.</p>
+</div>
+</div>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum"><a id="Page_410"></a>[Pg 410]</span></p>
+<h2 class="nobreak">PART FIFTH.<br>
+<span class="h_subtitle">SEPARATION AND ESTIMATION OF<br> BODIES CONTAINING NITROGEN.</span></h2>
+</div>
+
+<p><b>370. Nature of Nitrogenous Bodies.</b>—The nitrogenous bodies,
+valuable as foods, belong to the general class of proteids and
+albuminoids. They are composed chiefly of carbon, hydrogen, oxygen,
+sulfur and nitrogen. Some of them, as lecithin and nuclein, contain
+phosphorus instead of sulfur, but these resemble the fats rather than
+the proteids.</p>
+
+<p>Nitrogenous organic bodies of the class mentioned above are designated
+by the general name proteids. The term albumin is restricted in a
+physiological sense to a certain class of proteids. The term albuminoid
+is often used synonymously, as above, for proteids, but, more strictly
+speaking, it should be reserved for that class of bodies such as
+gelatin, mucin, keratin and the like, not really proteids, but,
+nevertheless, closely resembling them.<a id="FNanchor_337" href="#Footnote_337" class="fnanchor">[337]</a>
+In chemical composition the proteids are characterized by the relative
+constancy of their nitrogen content, the mean percentage of this
+element being about sixteen, but varying in some instances more than
+two units from that number.</p>
+
+<p><b>371. Classification of Proteids.</b>—Many classifications of the
+proteids have been given based on physical, chemical and physiological
+characteristics. In respect of origin, they are divided into two
+great classes, <i>viz.</i>, vegetable and animal. In respect of their
+physical and chemical properties the following classification of the
+proteids may be made.<a id="FNanchor_338" href="#Footnote_338" class="fnanchor">[338]</a></p>
+
+<p><i>Albumins.</i>—These are proteids soluble in water and not
+precipitated from their aqueous solutions by sodium chlorid or
+magnesium sulfate. They are easily coagulated by heat and are
+represented by three great classes, <i>viz.</i>, egg-, serum-, and
+lactalbumin.</p>
+
+<p>Egg albumin occurs in the white of egg; serum albumin is found in the
+serum of the blood. Vegetable albumins have been prepared from wheat,
+<span class="pagenum"><a id="Page_411"></a>[Pg 411]</span>
+rye, potatoes, and papaws. (<i>Carica Papaya</i>). These vegetable
+albumins are coagulated by heat at about 70° and are not precipitated
+by the salt solutions named above, nor by acetic acid. The myrosin of
+mustard seeds also resembles vegetable albumin.</p>
+
+<p><i>Globulins.</i>—These bodies are insoluble in water, soluble
+in dilute solutions of neutral salts, but precipitated therefrom
+by saturation with sodium chlorid or magnesium sulfate. They are
+coagulated by heat. Among others belonging to this group are serum
+globulin, fibrinogen, myosin, crystalin, and globin.</p>
+
+<p>Serum globulin is found in the serum of blood; cell globulin is found
+in lymph cells; fibrinogen occurs in the blood plasma; plasmin, in
+blood plasma; myosin, in dead muscles; vitellin, in the yolk of eggs;
+crystalin, in the lens of the eye; haemoglobin, in the red pigment of
+the blood; haemocyanin, in the blood of certain low grade animals.</p>
+
+<p>Vegetable globulins are found in the cereals, leguminous plants,
+papaws and other vegetables, and are divided into two groups, myosins
+and paraglobulins. The vegetable myosins coagulate at from 55° to
+60° and are precipitated from a saline solution by removing the salt
+by dialysis. In this form, however, they lose their true nature as
+globulins, becoming insoluble in weak saline solutions.</p>
+
+<p>The vegetable paraglobulins are coagulated at from 70° to 75°.
+Vegetable vitellin, which is not included in this classification, can
+be obtained in a crystalline form and of remarkable purity.<a id="FNanchor_339" href="#Footnote_339" class="fnanchor">[339]</a></p>
+
+<p><i>Albuminates.</i>—This name is given to the compounds of the
+proteids with metallic oxids or bases, and also to acid and alkali
+albumins. They are insoluble in water or dilute neutral salts, but
+easily soluble in strong acids or alkalies. Casein is a type of this group.</p>
+
+<p>Acid albumin is made from egg albumin by treatment with hydrochloric
+acid; alkali albumin is formed in egg albumin by the action of a dilute
+alkali; trinitroalbumin is formed from dry albumin by treatment with
+nitric acid; casein or caseinogen is the chief proteid in milk.</p>
+
+<p>The chief vegetable albuminates are legumin and conglutin. Legumin is a
+vegetable casein and occurs chiefly in peas, beans and other leguminous
+<span class="pagenum"><a id="Page_412"></a>[Pg 412]</span>
+seeds. It is prepared by extracting the meal of the seeds mentioned
+with dilute alkali, filtering the extract, precipitating with acetic
+acid, washing the precipitate with alcohol, and drying over sulfuric
+acid. Treated with sulfuric acid it yields leucin, tyrosin and glutamic
+and aspartic acids. Conglutin is prepared in a similar manner from almonds.</p>
+
+<p>It is probable that these bodies do not exist as such in the fresh
+seeds in question but are produced therein from the other proteids
+by the alkali used in extraction. A further description of vegetable
+proteids will be found in the special paragraphs devoted to the study
+of these bodies in the principal cereals.</p>
+
+<p><i>Proteoses.</i>—This name is applied to proteids which are not
+coagulated by heat, but most of them are precipitated by saturated
+solutions of neutral salts. They are also precipitated by nitric acid.
+They are formed from other proteids by the action of proteolytic
+ferments. The albumoses represent this group.</p>
+
+<p>Protoalbumose is soluble in distilled water and weak saline solutions
+and is precipitated by mercuric chlorid and copper sulfate.</p>
+
+<p>Heteroalbumose is insoluble in distilled water, but soluble in weak
+saline solutions, from which it separates when the salts are removed
+by dialysis. Deuteroalbumose is soluble in distilled water and saline
+solutions and is not precipitated on saturation with sodium chlorid. It
+is thrown out by mercuric chlorid but not by copper sulfate.</p>
+
+<p>Vegetable proteoses are known as phytalbumoses, two of which have been
+found in the juice of the papaw mentioned above. They have also been
+found in cereals.</p>
+
+<p><i>Peptones.</i>—These bodies are very soluble in water but are not
+thrown out by heat, by saturation with neutral salts, nor by nitric
+acid. They are completely precipitated by tannin and by strong alcohol.</p>
+
+<p>The peptones are the only soluble proteids which are not precipitated
+by saturation with ammonium sulfate. The principal animal varieties are
+hemi- and anti-peptones. These forms of proteids do not appear to exist
+as such in vegetable products but are produced in large quantities by
+treating other proteids with pepsin or pancreatin. In sprouting plants,
+there appears to be a widely diffused ferment capable of converting the
+<span class="pagenum"><a id="Page_413"></a>[Pg 413]</span>
+proteids of the cotyledons into peptonoid bodies and thus fitting them
+for entering the tissues of the new plant.</p>
+
+<p><i>Insoluble Proteids.</i>—This class includes a miscellaneous
+collection of nitrogenous bodies not belonging to any of the definite
+groups already mentioned. Fibrin and gluten are types of these
+insoluble bodies. Fibrin is formed from the fibrinogen of fresh blood
+and causes coagulation. When washed free of red blood corpuscles it is
+a white elastic solid. It is insoluble in water and is converted into
+albumoses and peptones by trypsin and pepsin. It swells up when treated
+with a very weak one-tenth per cent solution of hydrochloric acid and
+dissolves to acid albumin when heated therewith.</p>
+
+<p>Gluten is the most important of the insoluble vegetable proteids and
+forms the chief part of the nitrogenous constituents of wheat. It is
+readily prepared by washing wheat flour in cold water, as will be
+described further on. It is probably a composite body formed by the
+process of extraction from at least two proteid bodies existing in
+wheat. When dried it forms a horny elastic mass of a yellow-gray color.
+Gluten is composed of two bodies, one soluble the other insoluble
+in alcohol. The part insoluble in alcohol has been called vegetable
+fibrin, and the soluble part is subdivided into two portions, one
+unicedin or vegetable unicin, and the other glutin (gliadin) or
+vegetable gelatin. Gluten, according to some authorities, does not
+properly exist in wheat flour, but is formed therein by the action
+of water and certain ferments from free existing proteids. A better
+explanation of the composition of gluten is that of Osborne, which will
+be given further on.</p>
+
+<p><b>372. Albuminoids.</b>—In this paragraph the term albuminoids is not
+employed as synonymous with proteids but as characteristic of a class
+of bodies nearly resembling them, but, nevertheless, differing from
+them in many important particulars. Following is an abstract of their
+classification as given in Watt’s dictionary.<a id="FNanchor_340" href="#Footnote_340" class="fnanchor">[340]</a></p>
+
+<p><i>Collagen.</i>—The nitrogenous portions of connective tissues are
+largely composed of collagen. By boiling water it is converted into
+gelatin. It may be prepared from tendons as follows: The tendinous
+<span class="pagenum"><a id="Page_414"></a>[Pg 414]</span>
+tissues are shredded as finely as possible and extracted with cold
+water to remove the soluble proteids. Thereafter they are subjected
+for several days to the action of lime water, which dissolves the
+cement holding the fibers together. The residual insoluble matter is
+washed with water, weak acetic acid, and again with water. The residue
+is chiefly collagen, mixed, however, with some elastin and nuclein.
+With dilute acids and alkalies collagen swells up after the manner of
+fibrin. The organic nitrogenous matter of bone consists largely of
+collagen, which is sometimes called ossein.</p>
+
+<p><i>Gelatin.</i>—When the white fibers of collagen, obtained as above,
+are subjected to the action of boiling water or of steam under pressure
+they dissolve and form gelatin. Isinglass is a gelatin made from the
+swimming bladder of the sturgeon or other fish. Glue is an impure
+gelatin obtained from hides and bones. Pure gelatin may be prepared
+from the commercial article by removing all soluble salts therefrom by
+treatment with cold water, dissolving in hot water and filtering into
+ninety per cent alcohol. The gelatin separates in the form of white
+filaments and these are removed and dried. Gelatin is insoluble in
+cold but soluble in hot water. It is insoluble in alcohol, ether and
+chloroform. Its hot aqueous solutions deflect the plane of polarized
+light to the left. Its gyrodynat varies with temperature and degree of
+dilution and is also influenced by acids and alkalies. At 30° it is
+[α]<span class="fs_80"><sub>D</sub></span>³⁰° = -130.</p>
+
+<p>Gelatin is not precipitated by acetic acid nor lead acetate solution,
+in which respect it differs from chondrin.</p>
+
+<p>If boiled for a day, or in a short time if heated to 140° in a sealed
+tube, gelatin loses its power of setting and is split up into two
+peptonoid bodies, semi-glutin and hemi-collin. Gelatin is easily
+digested but cannot take the place of other proteids in nutrition.</p>
+
+<p><i>Mucin.</i>—This albuminoid, together with globulin, forms the
+principal part of connective tissue. It is also present in large
+quantities in mucus and is the chief lubricant of mucous membranes. It
+is extremely difficult to prepare mucin in a state of purity, and it is
+<span class="pagenum"><a id="Page_415"></a>[Pg 415]</span>
+not certain that it has ever been accomplished. It is precipitated
+but not rendered subsequently insoluble by sodium chlorid, magnesium
+sulfate and alcohol. When boiled with sulfuric acid it yields leucin
+and tyrosin and, with caustic soda, pyrocatechin.</p>
+
+<p><i>Met- and Paralbumin.</i>—Metalbumin is a form of mucin and differs
+from paralbumin by giving no precipitate when boiled. Both bodies yield
+reducing sugars when boiled with dilute sulfuric acid.</p>
+
+<p><i>Nuclein.</i>—The nitrogenous matters which form the nuclei of the
+ultimate cells are called nuclein. Nuclein resembles mucin in many
+physical properties but contains phosphorus. It is also, like mucin,
+resistant to pepsin digestion. The nuclein of eggs and milk probably
+contains iron. Nuclein is found also in cells of vegetable origin and
+in yeast and mildew.</p>
+
+<p><i>Nucleoproteids.</i>—These are bodies which yield both nuclein
+and albumin when boiled with water or treated with dilute acids or
+alkalies. Many nucleoproteids have the physical properties of mucus and
+the sliminess of the bile and of the synovial liquid is due to them.
+They are the chief nitrogenous constituent of all protoplasm.</p>
+
+<p><i>Chondrin.</i>—Chondrin is obtained from cartilage by boiling
+with water. The solutions of chondrin set on cooling in the manner
+of gelatin. They are precipitated by the same reagents used for
+throwing out gelatin and mucin. Chondrin is also levorotatory. By some
+authorities chondrin is regarded as a mixture of gelatin and mucin.</p>
+
+<p><i>Elastin.</i>—The elastic fibers of connective tissue are composed
+of this material. It can be prepared from the neck muscles by boiling
+with ether and alcohol to remove fats and then for a day and a half
+with water to extract the collagens. The residue is boiled with strong
+acetic acid and thereafter with strong soda until the fibers begin to
+smell. It is then treated with weak acetic acid and for a day with
+dilute hydrochloric acid. The acid is removed by washing with water
+and the residue is elastin. There is no solvent which acts on elastin
+without decomposing it. It is digested by both pepsin and trypsin with
+the formation of peptones.
+<span class="pagenum"><a id="Page_416"></a>[Pg 416]</span></p>
+
+<p><i>Keratin.</i>—This nitrogenous substance is found chiefly in hairs,
+nails, and horns. It is essentially an alteration proteid product due
+to peripheral exposure. It is prepared by digesting the fine ground
+material successively with ether, alcohol, water and dilute acids. The
+residue is keratin. An imperfect aqueous solution may be secured by
+heating for a long time under pressure to 200°. It is also dissolved
+by boiling the materials mentioned above with alkalies, and when the
+solution thus obtained is treated with water, hydrogen sulfid is
+evolved, showing that the sulfur of the molecule is loosely combined.</p>
+
+<p>Horn swells up when treated with dilute acetic acid and dissolves in
+the boiling glacial acid. When treated with hot dilute sulfuric acid it
+yields aspartic and volatile fat acids, leucin and tyrosin. Keratin,
+when burning, gives off a characteristic odor as is perceived in
+burning hair.</p>
+
+<p><i>Other Albuminoids.</i>—Among the albuminoids of less importance
+may be mentioned neurokeratin found in the medullary sheath of nerve
+fibers; chitin occurring in the tissues of certain invertebrates;
+conchiolin, found in the shells of mussels and snails; spongin,
+occurring in sponges; fibroin forming silk and spiders webs; and hyalin
+or hyalogen found in edible birds’ nests.</p>
+
+<p>The nitrogenous bases in flesh which are soluble in cold water,
+<i>viz.</i>, kreatin, kreatinin, carnin, sarkin and xanthin are not
+classed among the albuminoid bodies, since they have a much higher
+percentage of nitrogen than is found in true proteid bodies, and are
+further differentiated from them by the absence of sulfur.</p>
+
+<p><b>373. Other Forms of Nitrogen.</b>—In addition to the proteids and
+albuminoids mentioned above, agricultural products may contain nitrogen
+in the form of ammonia, amid nitrogen and nitric acid. The quantities
+of nitrogen thus combined are not large but often of sufficient
+magnitude to demand special study. In general, these bodies belong to
+transition products, representing stages in the transfer of nitrogen
+from the simple to complex forms of combination, or the reverse.</p>
+
+<p>For instance, the nitrogen which finally appears in the proteids of a
+<span class="pagenum"><a id="Page_417"></a>[Pg 417]</span>
+plant has entered its organism chiefly as nitric acid, and the
+nitric acid which is found in a vegetable product is therefore a
+representative of the quantity of unabsorbed nitrogen present in
+the tissues at the moment when the vital activity of the plant is
+arrested. In some instances, it is found that the absorption of
+nitrates by vegetable tissues takes place in far larger quantities than
+is necessary for their nutrition, and in these cases the excess of
+nitrates accumulates, sometimes to a remarkable extent. In a case cited
+in the reports of the Kansas Agricultural Experiment Station, where
+Indian corn was grown on ground which had been used for a hog pen, the
+quantity of potassium nitrate found in the dried stalks was somewhat
+remarkable. When one of the stalks was cut in two and tapped lightly
+upon a table, crystals of potassium nitrate were easily obtained in the
+form of fine powder. On splitting the cornstalk the crystals in the
+pith could be seen without the aid of a microscope. On igniting a piece
+of the dried stalk it burned rapidly with deflagration. The percentage
+of potassium nitrate in the dried material was 18.8. Cattle eating this
+fodder were poisoned.<a id="FNanchor_341" href="#Footnote_341" class="fnanchor">[341]</a></p>
+
+<p>In preserved meat products large quantities of oxidized nitrogen are
+often found, and these come from the use of potassium nitrate as a
+preserving and coloring agent. Ammonia is rarely found in vegetable
+tissues in greater quantities than mere traces, but may often exist in
+weighable amounts in animal products.</p>
+
+<p>Amid nitrogen is found rather constantly associated with proteid
+matters in vegetable products. Asparagin and glutamin are instances
+of amid bodies of frequent occurrence. Betain and cholin are found in
+cottonseed.</p>
+
+<p>The occurrence of nitrogen, in the form of alkaloids, is of interest
+to agricultural chemists in this country, chiefly from its presence
+as nicotin in tobacco and from a toxicological point of view, but
+in other localities the production of alkaloids, as for instance in
+opium, tea and coffee, is a staple agricultural industry. The methods
+of separating and determining these forms of nitrogen will be given
+further on. This description can evidently not include an extended
+compilation of the methods of separating and determining alkaloidal
+bodies, with the exception of those with which the agricultural analyst
+<span class="pagenum"><a id="Page_418"></a>[Pg 418]</span>
+will be called upon frequently to deal, <i>viz.</i>, nicotin and
+caffein and nitrogenous bases such as betain and cholin.</p>
+
+<h3>QUALITIVE TESTS FOR<br> NITROGENOUS BODIES.</h3>
+
+<p><b>374. Nitric Acid.</b>—Any nitric acid or nitrate which an
+agricultural product may contain may be leached out by treating the
+fine-ground material with cold water. From vegetable matters this
+extract is evaporated to a small bulk, filtered, if necessary, and
+tested for nitric acid by the usual treatment with ferrous sulfate
+and sulfuric acid. In the case of vegetable substances there will not
+usually be enough of organic matter to interfere with the delicacy of
+the reaction, but in animal extracts this may occur. Colored extracts
+should be decolorized with animal char (bone-black) before they are
+subjected to examination. It is not well to attempt to remove the
+organic matters, but, since they are more insoluble in water than the
+nitrates, the solution containing both may be evaporated to dryness
+and treated with a quantity of cold water insufficient for complete
+solution. The nitrates will be found in the solution obtained in a
+larger proportionate quantity than before.</p>
+
+<p><b>375. Amid Nitrogen.</b>—One or more atoms of the hydrogen in
+ammonia may be replaced by acid or basic bodies (alcohol radicles).
+In the former cases amids, in the latter amins result. In the ratio
+of displacement there are formed primary, secondary, and tertiary
+bodies determined by the number of hydrogen atoms replaced. The primary
+amids are the only ones of these bodies that are of interest in this
+connection.</p>
+
+<p>The amids are easily decomposed, even on heating with water and the
+more readily with acids and alkalies, the amido radicle being converted
+into ammonia. A type of these reactions is given below.</p>
+
+<p class="f105">CH₃.CO.NH₂ + H₂O = CH₂.CO.OH + H₃N.</p>
+
+<p>On boiling an amid with hydrochloric acid, the ammonia is procured
+as chlorid whence it is easily expelled by heating with an alkali.
+In a body free of ammonia, an amid is easily detected by subjecting
+the substance containing it to the action of hot hydrochloric acid,
+filtering, neutralizing the free acid with sodium hydroxid, adding an
+<span class="pagenum"><a id="Page_419"></a>[Pg 419]</span>
+excess thereof and distilling into an acid.<a id="FNanchor_342" href="#Footnote_342" class="fnanchor">[342]</a> In case the quantity
+of ammonia produced is very small it may be detected by the nessler
+reagent.<a id="FNanchor_343" href="#Footnote_343" class="fnanchor">[343]</a>
+Amids are soluble in a fresh, well washed preparation of cupric hydrate
+suspended in water. The hydrate also passes into solution forming a
+liquid of a deep blue color.</p>
+
+<p>If amids be added to a cold solution of potassium nitrate in sulfuric
+acid free nitrogen is evolved.</p>
+
+<p><b>376. Ammoniacal Nitrogen.</b>—This combination of nitrogen may be
+detected by distilling the sample, or an aqueous extract thereof, with
+magnesia or barium carbonate. The ammonia is collected in an acid and
+detected therein by the usual qualitive reactions.</p>
+
+<p><b>377. Proteid Nitrogen.</b>—There are a few general qualitive
+reactions for proteid nitrogen and some special ones for distinct forms
+thereof. Below will be given a few of those reactions which are of most
+importance to the agricultural analyst:</p>
+
+<p><i>Conversion into Ammonia.</i>—All proteid matters are converted
+into ammonia on boiling with strong sulfuric acid in presence of an
+oxygen carrier. Mercury is the substance usually selected to effect the
+transfer of the oxygen. Bodies which are found to be free of nitrates,
+ammonia and amids, are subjected directly to oxidation with sulfuric
+acid, and the ammonia produced thereby is distilled and detected in
+the manner already suggested. If nitrogen be present in the form of
+ammonia, amids and nitrates, the substance may be heated with an acid,
+hydrochloric or acetic, thrown on a filter, washed with hot dilute acid
+and the residue tested as above for proteid nitrogen.</p>
+
+<p><i>Biuret Reaction.</i>—When proteid matter is dissolved in sulfuric
+acid, the solution, made alkaline with potassium hydroxid and treated
+with a few drops of a solution of copper sulfate, gives a violet
+coloration. This is commonly known as the biuret reaction, because the
+substance <b>C₂H₆N₃O₂</b>, biuret, left on heating urea to 160° gives the
+coloration noted in the conditions mentioned.</p>
+
+<p>It has been found by Bigelow, in this laboratory, that if a solution is
+to be examined containing a very small amount of a proteid or similar
+body, the copper sulfate solution should not contain more than four
+<span class="pagenum"><a id="Page_420"></a>[Pg 420]</span>
+grams of <b>CuSO₄.5H₂O</b> in 100 cubic centimeters of water, and the test
+should first be made by adding to the solution one or two drops of
+this copper sulfate solution, and then a strong excess of potassium
+or sodium hydroxid. The test may be repeated, using from one-half to
+two cubic centimeters of the copper sulfate solution, according to the
+amount of proteid present. If too much of the copper sulfate solution
+be employed its color may conceal that of the reaction.</p>
+
+<p>Heating to the boiling point sometimes makes the violet color more
+distinct.</p>
+
+<p>If a solid is to be examined it is first suspended in water, and in
+this state treated in the same manner as a solution. If solution is not
+complete, the mixture should be filtered when the color produced may be
+observed in the filtrate.</p>
+
+<p>Proteoses and peptones give a red to red-violet and other proteids a
+violet to violet-blue coloration.</p>
+
+<p><i>Xanthoproteic Reaction.</i>—Strong nitric acid produces a yellow
+coloration of proteid matter, which is intensified on warming. On
+treating the yellow mixture with ammonia in slight excess the color is
+changed to an orange or red tint.</p>
+
+<p><b>378. Qualitive Tests for Albumin.</b>—Albumin is one of the chief
+proteids and exists in both animal and vegetable substances. It is
+soluble in cold water and may therefore be separated from many of its
+nearly related bodies which are insoluble in that menstruum. In aqueous
+solutions its presence may be determined by the general reactions for
+proteid matters given above or by the following tests:</p>
+
+<p><i>Precipitation by Heat.</i>—Albumin is coagulated by heat. Vegetable
+albumins become solid at about 65° and those of animal origin at a
+somewhat higher temperature (75°). Some forms of animal albumin,
+however, as for instance that contained in the serum, coagulate at a
+lower temperature.</p>
+
+<p><i>Precipitation by Acids.</i>—Dilute acids also precipitate albumins
+especially with the aid of heat. Practically all the albumins are
+thrown out of solution by application of heat in the presence of dilute
+acids.</p>
+
+<p><i>Mercuric Salts.</i>—Acid mercuric nitrate and a mixture of mercuric
+chlorid, potassium iodid and acetic acid completely precipitate all
+albuminous matters.<a id="FNanchor_344" href="#Footnote_344" class="fnanchor">[344]</a></p>
+
+<p><span class="pagenum"><a id="Page_421"></a>[Pg 421]</span>
+The yellow or red color produced on heating albumin with the mercuric
+nitrate is known as Million’s reaction.</p>
+
+<p><b>379. Qualitive Test for Peptones and Albuminates.</b>—When peptones
+and albuminates are dissolved in an excess of glacial acetic acid and
+the solution treated with sulfuric acid a violet color is produced and
+also a faint fluorescence.</p>
+
+<p><i>Separation of Peptones and Albumoses.</i>—In a solution of peptones
+and albumoses the latter may be precipitated by saturating the solution
+with finely powdered zinc or ammonium sulfate.</p>
+
+<p><i>Action of Phosphotungstic Acid.</i>—All proteid matters in aqueous,
+alkaline or acid solutions, are precipitated by sodium phosphotungstate
+in a strongly acid solution. Acetic, phosphoric, or sulfuric acid may
+be used for producing the required acidity, preference being given to
+the latter.</p>
+
+<p><i>Action of Trichloracetic Acid.</i>—In the precipitation of albumin
+by trichloracetic acid, there is formed a compound of the two bodies
+which to 100 parts of albumin has 26.8 parts of the trichloracetic acid.</p>
+
+<p>The different albuminoid bodies obtained by precipitation behave in
+a similar manner. There are formed flocculent precipitates insoluble
+both in dilute and concentrated acids in the cold and also at a high
+temperature, with the exception of the hemialbumose compound.<a id="FNanchor_345" href="#Footnote_345" class="fnanchor">[345]</a></p>
+
+<p>Albumin peptone, however, gives with the acid named in concentrated
+solution a precipitate easily soluble in an excess of the reagent. In
+the analysis of cow’s milk but not of human milk, this acid can be used
+for the estimation of the albuminoid substances. With both kinds of
+milk it can be used for the estimation of the albumin after the removal
+of the casein.</p>
+
+<p>After precipitation of the albuminoid bodies, the milk sugar can be
+estimated by polarizing the filtrate and, volumetrically after removal
+of the excess of the acid by evaporation. By means of trichloracetic
+acid it is possible to separate albumin peptone from mucus and mucus
+peptone. A similar reaction is also produced by dichloracetic acid, but
+the reaction with this last agent is less delicate than with the other.
+Neither mucus nor albumin is precipitated by chloracetic acid.
+<span class="pagenum"><a id="Page_422"></a>[Pg 422]</span></p>
+
+<p><b>380. Action of Albumins on Polarized Light.</b>—Many of the
+albumins and albuminates, when in solution, strongly deflect the plane
+of polarized light to the left.<a id="FNanchor_346" href="#Footnote_346" class="fnanchor">[346]</a></p>
+
+<p>The gyrodynats of some of the albumins and albuminates are given below:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Serum albumin</td>
+      <td class="tdl_ws1">[α]<span class="fs_80"><sub>D</sub></span> =</td>
+      <td class="tdl_wsp">-57°.3 to -64°.6.</td>
+   </tr><tr>
+      <td class="tdl">Egg albumin</td>
+      <td class="tdl_ws1">[α]<span class="fs_80"><sub>D</sub></span> =</td>
+      <td class="tdl_wsp">-35°.5 to -38°.1.</td>
+   </tr><tr>
+      <td class="tdl">Serum globulin</td>
+      <td class="tdl_ws1">[α]<span class="fs_80"><sub>D</sub></span> =</td>
+      <td class="tdl_wsp">-47°.8.</td>
+   </tr><tr>
+      <td class="tdl">Milk albumin</td>
+      <td class="tdl_ws1">[α]<span class="fs_80"><sub>D</sub></span> =</td>
+      <td class="tdl_wsp">-76°.0 to -91°.0.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Our knowledge of the gyrodynatic numbers of the proteids and allied
+bodies is too fragmentary to be of any great help in analytical work.
+In practice, the rotatory power of these bodies becomes a disturbing
+force in the determination of milk sugar.<a id="FNanchor_347" href="#Footnote_347" class="fnanchor">[347]</a>
+A further study of this property of certain proteids may lead to
+analytical processes for their detection and determination, but no
+reliable methods for this can now be recorded.</p>
+
+<p><b>381. Alkaloidal Nitrogen.</b>—Only a general statement can be made
+here in respect of the detection of alkaloidal nitrogen in vegetable
+or animal tissues. Alkaloids are not found in healthy animal tissues
+and the description of methods for isolating and detecting ptomaines is
+foreign to the purpose of this work. In vegetable tissues the presence
+of alkaloids may be established by the following methods of examination.</p>
+
+<p>The fine-ground tissues are made to pass a sieve of half millimeter
+mesh and when suspended in water are acidified with sulfuric. The
+mixture is then thoroughly extracted by shaking in a separatory funnel
+with petroleum ether, benzene and chloroform, successively. Some
+resins, glucosids and a few alkaloidal bodies not important here are
+extracted by this treatment.</p>
+
+<p>The residue is made distinctly alkaline with ammonia and treated
+as above with the same solvents. In the solution obtained as last
+mentioned nearly all the alkaloidal bodies found in plants are contained.</p>
+
+<p>All the alkaloids in a plant may be obtained by digesting the finely
+divided material with dilute sulfuric acid. The acid solution thus
+obtained is made nearly neutral with ammonia or magnesia, concentrated
+<span class="pagenum"><a id="Page_423"></a>[Pg 423]</span>
+to a sirup, and gums, mucilage, etc. thrown out by adding about three
+volumes of ninety-five per cent alcohol. The alkaloids are found in the
+filtrate. The alcohol is evaporated from the filtrate and the residue
+tested for alkaloids by group reagents.<a id="FNanchor_348" href="#Footnote_348" class="fnanchor">[348]</a>
+Potassium mercuric iodid and phosphotungstic and molybdic acids are
+types of these reagents.</p>
+
+<p>The same group reagents may also be applied to the extracts obtained
+with petroleum ether, benzene and chloroform, in all cases, after the
+removal of the solvents by evaporation.</p>
+
+<h3>ESTIMATION OF NITROGENOUS BODIES<br> IN AGRICULTURAL PRODUCTS.</h3>
+
+<p><b>382. Total Nitrogen.</b>—Any one of the methods heretofore
+described for the estimation of total nitrogen in soils or fertilizers
+is applicable for the same purpose to agricultural products. One
+among these, however, is so superior in the matter of convenience and
+certainty, as to make it preferable to any other. The moist combustion
+of the sample with sulfuric acid with subsequent distillation of the
+ammonia produced is the process which is to be recommended.<a id="FNanchor_349" href="#Footnote_349" class="fnanchor">[349]</a></p>
+
+<p>The usual precautions for securing a representative sample should be
+observed, but no further directions are needed. In all cases hereafter,
+where the estimation of nitrogen is enjoined, it is understood that the
+moist combustion process is to be used unless otherwise stated.</p>
+
+<p><b>383. Estimation of Ammoniacal Nitrogen.</b>—If the distillation
+of ammonia be accomplished with the aid of magnesia alba or barium
+carbonate it may be safely conducted on the finely ground materials
+or, in case of animal bodies, in as fine a state of subdivision as
+may be conveniently secured. Since the salts of ammonia are easily
+soluble in water they may be all obtained in aqueous solution, and the
+distillation of this solution with magnesia gives correct results.
+Experience has shown that the stronger alkalies, such as sodium and
+potassium hydroxids, cannot be safely used in the distillation of
+ammonia from mixtures containing organic nitrogenous materials because
+<span class="pagenum"><a id="Page_424"></a>[Pg 424]</span>
+of the tendency of these bodies to decomposition, in the circumstances,
+yielding a portion of their nitrogen as ammonia. Barium carbonate acts
+with less vigor on non-ammoniacal nitrogenous matters than magnesia,
+and in some cases, as pointed out further on, may be substituted
+therefor with advantage. There is no danger of failing to obtain a part
+of the ammonia on distillation with magnesia provided the latter does
+not contain more than a trace of carbonate.<a id="FNanchor_350" href="#Footnote_350" class="fnanchor">[350]</a></p>
+
+<p>When no easily decomposable organic nitrogenous matters are present,
+the distillation may be conducted with the stronger alkalies in the
+manner prescribed.<a id="FNanchor_351" href="#Footnote_351" class="fnanchor">[351]</a>
+All the necessary details of conducting the distillation are found in
+the preceding volumes of this work.</p>
+
+<p><b>384. Estimation of Amid Nitrogen.</b>—In bodies containing no
+ammonia, or from which the ammonia has been removed by the method
+described in the preceding paragraph, the nitrogen in the amid bodies
+is converted into ammonia by boiling for about an hour with five per
+cent sulfuric or hydrochloric acid. The ammonia thus produced is
+estimated in the usual manner after distillation over magnesia free
+of carbonate. The free acid is exactly neutralized with sodium or
+potassium carbonate before the addition of the magnesia. The results
+are given in terms of asparagin. The reaction which takes place in the
+decomposition of the amid body is indicated by the following equation:</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl_ws1">Asparagin.</td>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdl">Sulfuric<br>&nbsp; acid.</td>
+      <td class="tdl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">2C₄H₈N₂O₃ + 2H₂O</td>
+      <td class="tdl">&nbsp; + &nbsp;</td>
+      <td class="tdl">H₂SO₄</td>
+      <td class="tdl">&nbsp; =</td>
+   </tr><tr>
+      <td class="tdc" colspan="4">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">Aspartic acid.</td>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdc">Ammonium<br>sulfate.</td>
+      <td class="tdl">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">2C₄H₇NO₄</td>
+      <td class="tdl">&nbsp; + &nbsp;</td>
+      <td class="tdl">(H₄N)₂SO₄.</td>
+      <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Half of the nitrogen contained in the amid body is thus obtained as
+ammonia.</p>
+
+<p>It is advisable to calculate all the amid nitrogen in agricultural
+products as asparagin.</p>
+
+<p><b>385. Sachsse’s Method.</b>—A method for the determination of amid
+bodies by liberation of free nitrogen has been described by Sachsse
+and Kormann.<a id="FNanchor_352" href="#Footnote_352" class="fnanchor">[352]</a>
+It is based on the reaction which takes place when amid bodies are
+brought into contact with nitrites in presence of an acid. The mixture
+of the reagents by which the gas is set free is accomplished in the
+<span class="pagenum"><a id="Page_425"></a>[Pg 425]</span>
+apparatus shown in <a href="#FIG_103">Fig. 103</a>. The vessel <i>A</i>
+has a capacity of about fifty cubic centimeters and carries a stopper
+with three perforations for the arrangement shown.</p>
+
+<div class="figcontainer smcap">
+  <div class="figsub">
+   <img id="FIG_103" src="images/fig103.jpg" alt="" width="185" height="405" >
+   <p class="center">Fig. 103.—Apparatus<br> for Amid Nitrogen.</p>
+  </div>
+  <div id="FIG_104" class="figsub">
+   <img src="images/fig104.jpg" alt="" width="300" height="401" >
+   <p class="center">Fig. 104.—Sachsse’s Eudiometer.</p>
+   </div>
+</div>
+
+<p>About six cubic centimeters of a concentrated aqueous solution of
+potassium nitrite are placed in <i>A</i> and the lower parts of the
+tubes <i>a</i> and <i>b</i> are filled with water to a little above
+<i>e</i> in order to exclude the air therefrom. Dilute sulfuric acid
+is placed in one of the funnels and an aqueous solution of the amid
+in the other. The air is displaced from the empty part of <i>A</i> by
+introducing the sulfuric acid, a little at a time, whereby nitrous acid
+and nitric oxid are evolved. This operation is continued until all the
+air has been driven out through <i>c d</i>, the open end of <i>d</i>
+being kept in the liquid in the dish shown in <a href="#FIG_104">Fig. 104</a>.
+The eudiometer in which the evolved nitrogen is measured is shown in
+<a href="#FIG_104">Fig. 104</a>, and should have a capacity of about
+fifty cubic centimeters, and be graduated to fifths. It is filled with
+the solution of ferrous sulfate contained in <i>B</i> by sucking at
+<i>g</i>, after which the clamp <i>h</i> is replaced, the cock <i>f</i>
+closed, and the free end of <i>d</i> placed in the lower end of the
+eudiometer. The solution of the amid is run slowly into the generator
+<i>A</i>, <a href="#FIG_103">Fig. 103</a>, together with small additional quantities
+of the sulfuric acid when the evolution of gas becomes slow. From time to time
+<i>h</i> is opened and fresh quantities of the ferrous solution allowed
+<span class="pagenum"><a id="Page_426"></a>[Pg 426]</span>
+to flow into the eudiometer. Any trace of the amid remaining in the
+funnel is washed into <i>A</i> with pure water, with care to avoid the
+introduction of air. When the liquid in <i>A</i> assumes a permanent
+blue color the decomposition is complete. The residual gas is driven
+out of <i>A</i> by filling with water. The tubes <i>d</i> and <i>h</i>,
+after all the nitric oxid is absorbed, are removed from the eudiometer
+which is transferred to a cylinder containing water and immersed
+therein until the two liquid surfaces are at the same level and the
+volume of the nitrogen observed. After correction for temperature and
+pressure, the weight of the nitrogen is calculated. Twenty-eight parts
+by weight of nitrogen correspond to 150 of pure asparagin, 181 of
+tyrosin and 131 of leucin.<a id="FNanchor_353" href="#Footnote_353" class="fnanchor">[353]</a>
+This method of procedure is difficult of manipulation and is apt to
+give results that are too high. It cannot be preferred to the more
+simple and accurate processes already described.</p>
+
+<p><b>386. Preparation of Asparagin.</b>—In case the analyst desires to
+prepare a quantity of asparagin for comparative purposes it may be
+easily accomplished in the following way: A sufficient quantity of
+pease or beans is sprouted in a dark place and allowed to grow until
+the reserve food of the seed is exhausted. The young sprouts are
+gathered, shredded and subjected to strong pressure. The juice thus
+obtained is boiled to coagulate the albumin, and thrown on a filter.
+The filtrate is evaporated to a thin sirup and set aside to allow the
+asparagin to separate in a crystallized form. If the crystals at first
+formed are colored they may be dissolved, decolorized with bone-black,
+and recrystallized. Instead of the above method the young shoots may be
+shredded, extracted with hot water and the extract treated as above. A
+larger yield of the asparagin is obtained by the latter process than by
+the one mentioned above.<a id="FNanchor_354" href="#Footnote_354" class="fnanchor">[354]</a></p>
+
+<p><b>387. Detection and Estimation of Asparagin and Glutamin.</b>—Of all
+the amid bodies asparagin is the most important from an agricultural
+standpoint, because of its wide distribution in vegetable products.<a id="FNanchor_355" href="#Footnote_355" class="fnanchor">[355]</a>
+Asparagin is easily obtained from the aqueous extracts of plants by
+crystallization.<a id="FNanchor_356" href="#Footnote_356" class="fnanchor">[356]</a>
+In addition to its crystalline characteristics asparagin may be
+identified by the following tests. Heated with alkalies, including
+<span class="pagenum"><a id="Page_427"></a>[Pg 427]</span>
+barium hydroxid, asparagin yields ammonia. Boiled with dilute acids
+it forms ammonium salts. A warm aqueous solution dissolves freshly
+prepared copper hydroxid with the production of a deep blue color.
+Sometimes, on cooling, crystals of the copper compound formed are
+separated. Asparagin crystallizes with one molecule of water. Glutamin
+gives essentially the reactions characteristic of asparagin, but
+crystallizes without water in small white needles. Asparagin is
+easily detected with the aid of the microscope by placing sections of
+vegetable tissues containing it in alcohol. After some time microscopic
+crystals of asparagin are separated. The presence of large quantities
+of soluble carbohydrates seriously interferes with the separation of
+asparagin in crystalline form.</p>
+
+<p>For the detection of glutamin the liquid containing it is boiled with
+dilute hydrochloric acid, by which ammonia and glutamic acid are
+formed. On the addition of lead acetate to the solution the glutamic
+acid is thrown out as a lead salt, in which, after its decomposition
+with hydrogen sulfid, the characteristic properties of glutamic acid
+can be established.</p>
+
+<p>The above process is chronophagous and also uncertain where the
+quantity of glutamin is very small and that of other soluble organic
+matters very large. A much better process, both for the detection
+of glutamin and asparagin, is the following, based on the property
+possessed by mercuric nitrate of precipitating amids.</p>
+
+<p>The aqueous extract containing the amid bodies is mixed with lead
+acetate until all precipitable matters are thrown out and the mixture
+poured into a filter. To the filtrate is added a moderately acid
+solution of mercuric nitrate. The precipitate produced is collected
+on a filter, washed, suspended in water, decomposed with hydrogen
+sulfid and again filtered. The amid bodies (glutamin, asparagin, etc.)
+are found in the filtrate and can be detected and estimated by the
+processes already described. A reaction showing the presence of an amid
+body is not a positive proof of the presence of asparagin or glutamin,
+since among other amids, allantoin may be present. This substance is
+<span class="pagenum"><a id="Page_428"></a>[Pg 428]</span>
+found in the sprouts of young plants and also in certain cereals, as
+shown by researches in this laboratory.<a id="FNanchor_357" href="#Footnote_357" class="fnanchor">[357]</a>
+Allantoin, glutamin, and asparagin, when obtained in solution by
+the above process, may be secured, by careful evaporation and
+recrystallization, in well defined crystalline forms. Asparagin gives
+lustrous, rhombic prisms, easily soluble in hot water, but insoluble in
+alcohol and ether.</p>
+
+<p>Allantoin is regarded as a diureid of glyoxalic acid and has the
+composition represented by the formula C₄H₆N₄O₃. It crystallizes in
+lustrous prisms having practically the same solubility as asparagin.</p>
+
+<p>Glutamin is the amid of amidoglutaric acid. It crystallizes in fine
+needles. Its structural formula is represented as</p>
+
+<ul class="index fs_105">
+<li class="isub7">CO.NH₂</li>
+<li class="isub7">/</li>
+<li class="isub3">C₃H₅(NH₂)</li>
+<li class="isub7">\</li>
+<li class="isub7">CO₂H.</li>
+</ul>
+
+<p><b>387. Cholin and Betain.</b>—Cholin is a nitrogenous base found
+in both animal and plant tissues. Its name is derived from the
+circumstance that it was first discovered in the bile. It is found in
+the brain, yolk of eggs, hops, beets, cottonseed and many other bodies.
+When united with glycerolphosphoric acid it forms lecithin, a compound
+of great physiological importance. From a chemical point of view,
+cholin is oxyethyltrimethyl-ammonium hydroxid,</p>
+
+<ul class="index fs_105">
+<li class="isub5">OH</li>
+<li class="isub5">/</li>
+<li class="isub3">C₂H₄<span class="ws6">; (C₅H₁₅NO₂).</span></li>
+<li class="isub5">\</li>
+<li class="isub5">N(CH₃)₃.OH</li>
+</ul>
+
+<p>It is crystallized with difficulty and is deliquescent. Its most
+important compound, from an analytical point of view, is its platinum
+salt <b>C₅H₁₄ONCl₂PtCl₄</b>. This salt crystallizes in red-yellow plates and
+is insoluble in alcohol.</p>
+
+<p>Betain, <b>C₅H₁₁NO₂</b>, is the product of the oxidation of cholin.</p>
+
+<p>In this laboratory the bases are separated from cottonseed and from
+each other by the process described below.<a id="FNanchor_358" href="#Footnote_358" class="fnanchor">[358]</a></p>
+
+<p>About five pounds of fine-ground cottonseed cake are extracted with
+seventy per cent alcohol. The material should not be previously treated
+with dilute mineral acids because of the danger of converting a part
+of the cholin into betain. The alcohol is removed from the filtered
+extract and the residue dissolved in water. The aqueous solution is
+treated with lead acetate until no further precipitation takes place,
+thrown on a filter, the lead removed from the filtrate with hydrogen
+<span class="pagenum"><a id="Page_429"></a>[Pg 429]</span>
+sulfid and the liquid evaporated to a viscous syrup. The sirup is
+extracted with alcohol containing one per cent of hydrochloric acid.
+The solution thus obtained is placed in a deep beaker and the bases
+precipitated by means of an alcoholic solution of mercuric chlorid.
+The complete separation of the salts requires at least two weeks.</p>
+
+<p>The double salts of the bases and mercury thus obtained, after freeing
+from the mother liquor, are recrystallized from a solution in water
+and from the pure product thus obtained the mercury is removed after
+solution in water, by hydrogen sulfid. The filtrate, after separating
+the mercury, contains the bases as chlorids (hydrochlorates). The
+solution of the chlorids is evaporated slowly in (pene) vacuo to a
+thick sirup and set over sulfuric acid to facilitate crystallization.
+The hydrochlorates are obtained in this way colorless and in
+well-shaped crystalline forms.</p>
+
+<p>In a quantitive determination, a small amount of the fine meal is
+extracted at once with one per cent hydrochloric acid in seventy per
+cent alcohol, the salts obtained purified as above and weighed.</p>
+
+<p>The following process serves to determine the relative proportions of
+cholin and betain in a mixture of the two bases.</p>
+
+<p>A definite weight of the chlorids, prepared as directed above, is
+extracted by absolute alcohol. This treatment dissolves all the cholin
+chlorid and a little of the betain salt. The alcoholic solution is
+evaporated and again extracted with absolute alcohol. This process is
+repeated three times and at the end the cholin chlorid is obtained
+free of betain. In a sample of cottonseed cake examined in this
+laboratory the two bases were found present in the following relative
+proportions, <i>viz.</i>, cholin 17.5 per cent, betain 82.5 per cent.
+Thus purified the cholin is finally precipitated by platinum chlorid.
+For a description of the special reaction, by means of which cholin and
+betain are differentiated, the paper cited above may be consulted.</p>
+
+<p>These bodies have acquired an economic interest on account of their
+occurrence in cottonseed meal, which is so extensively used as a cattle
+food. It is evident from the relative proportions in which they occur
+<span class="pagenum"><a id="Page_430"></a>[Pg 430]</span>
+that the less nocuous base, betain, is the more abundant. It is
+possible, however, that the base originally formed is cholin and that
+betain is a secondary product.</p>
+
+<p>Experience has shown that it is not safe to feed cottonseed meal to
+very young animals, while moderate rations thereof may be given to
+full-grown animals without much expectation of deleterious results. In
+the case of toxic effects it is fair to presume that a meal has been
+fed in which the cholin is relatively more abundant than the betain.</p>
+
+<p><b>389. Lecithin.</b>—Lecithin is a nitrogenous body, allied both to
+the fats and proteids and containing glycerol and phosphoric acid. Its
+percentage composition is represented with some accuracy by the formula
+<b>C₄₂H₈₆NPO₉</b>, or according to Hoppe-Seyler, <b>C₄₄H₉₀NPO₉</b>. It appears to
+be a compound of cholin with glycerolphosphoric acid. It is widely
+distributed both in animal and vegetable organisms, in the latter
+especially in pease and beans.</p>
+
+<p>From a physiological point of view, lecithin is highly important as the
+medium for the passage of phosphorus from the organic to the inorganic
+state, and the reverse. This function of lecithin has been thoroughly
+investigated in this laboratory by Maxwell.<a id="FNanchor_359" href="#Footnote_359" class="fnanchor">[359]</a></p>
+
+<p>In the extraction of lecithin from seeds (pease, beans, etc.) it is not
+possible to secure the whole of the substance by treatment with ether
+alone.<a id="FNanchor_360" href="#Footnote_360" class="fnanchor">[360]</a></p>
+
+<p>The extraction of the lecithin may, however, be entirely accomplished
+by successive treatments for periods of about fifteen hours with pure
+ether and alcohol. This is better than to mix the solvents, since, in
+this case, the ether having the lower boiling point is chiefly active
+in the extraction. When the extraction is accomplished by digestion
+and not in a continuous extracting apparatus the two solvents may be
+mixed together and thus used with advantage. After the evaporation of
+the solvents, the lecithin is ignited with mixed sodium and potassium
+carbonate whereby the organic phosphorus is secured without loss in an
+inorganic form. Where greater care is desired, the method described for
+organic phosphorus in soils may be used.<a id="FNanchor_361" href="#Footnote_361" class="fnanchor">[361]</a>
+The inorganic phosphorus thus obtained is estimated in the usual way as
+magnesium pyrophosphate.
+<span class="pagenum"><a id="Page_431"></a>[Pg 431]</span></p>
+
+<p>For analytical purposes, the extraction of lecithin from vegetable
+substances is conducted in this laboratory as follows:<a id="FNanchor_362" href="#Footnote_362" class="fnanchor">[362]</a>
+The fine-ground pea or bean meal is placed in an extraction apparatus
+and treated continuously with anhydrous ether for fifteen hours. The
+ether in the apparatus is replaced with absolute alcohol and the
+extraction continued for six hours longer. The alcoholic extract is
+evaporated to dryness and treated with ether. The part of the lecithin
+at first insoluble in ether becomes soluble therein after it has been
+removed from the vegetable tissues by alcohol. Moreover, any trace of
+inorganic phosphorus which may have been removed by the alcohol, is
+left undissolved on subsequent treatment with ether. The ether extract
+from the alcohol residue is added to that obtained directly, the ether
+removed by evaporation, and the total lecithin oxidized and the residue
+used for the estimation of phosphorus as already described.</p>
+
+<p>In determining the lecithin in eggs, the procedure employed for
+vegetable tissues is slightly changed.<a id="FNanchor_363" href="#Footnote_363" class="fnanchor">[363]</a>
+The whole egg, excluding the shell, is placed in a flask with a reflux
+condenser and boiled for six hours with absolute alcohol. The alcohol
+is then removed from the flask by evaporation and the residue treated
+in like manner with ether for ten hours. The ether is removed and the
+dry residue rubbed to a fine powder, placed in an extractor and treated
+with pure ether for ten hours. The extract thus secured is oxidized
+after the removal of the ether by fusion with mixed alkaline carbonates
+and the phosphorus determined in the usual way.</p>
+
+<p><b>390. Factor for Calculating Results.</b>—The percentage of lecithin
+is calculated from the weight of magnesium pyrophosphate obtained by
+multiplying it by the factor, 7.2703.<a id="FNanchor_364" href="#Footnote_364" class="fnanchor">[364]</a>
+This factor is calculated from the second formula for lecithin given
+above, in which the percentage of phosphorus pentoxid, <b>P₂O₅</b>, is
+8.789.</p>
+
+<p class="blockquot"><i>Example.</i>—In fifty-four grams of egg,
+exclusive of the shell, is found an amount of organic phosphorus
+yielding 0.0848 gram of magnesium pyrophosphate. Then 0.0848 × 7.2703
+= 0.61652 and 0.61652 × 100 ÷ 54 = 1.14. Therefore the percentage of
+lecithin in the egg is 1.14.</p>
+
+<p><span class="pagenum"><a id="Page_432"></a>[Pg 432]</span>
+<b>391. Estimation of Alkaloidal Nitrogen.</b>—The alkaloids contain
+nitrogen in a form more difficult of oxidation than that contained in
+proteid or albuminoid forms. It is doubtful whether any of the nitrogen
+in alkaloids becomes available for plant nutrition by any of the usual
+processes of fermentation and decay to which nitrogenous bodies are
+submitted in the soil. Likewise, it is true that it is not attacked by
+the digestive processes in any way preparatory to its assimilation as
+food by the animal tissues. Alkaloidal nitrogen is therefore not to be
+regarded as a food either for the animal or plant.</p>
+
+<p>For the general methods of estimating alkaloids the reader is referred
+to standard works on plant chemistry and toxicology. The alkaloids of
+interest in this manual are those which are found in tobacco, tea,
+coffee and a few other products of agricultural importance. The best
+methods of isolating and estimating these bodies will be given in the
+part of the volume devoted to the special consideration of the articles
+mentioned.</p>
+
+<h3>SEPARATION OF PROTEID BODIES<br> IN VEGETABLE PRODUCTS.</h3>
+
+<p id="P_392"><b>392. Preliminary Treatment.</b>—The chief disturbing components
+of vegetable tissues, in respect of their influence on the separation
+and estimation of the proteid constituents, are fats and oils and
+coloring matters. In many cases these bodies are present in such
+small quantities as to be negligible, as, for instance, in rice. In
+other cases they exist in such large proportions as to present almost
+insuperable difficulties to analytical operations, as is the case with
+oily seeds. In all instances, however, it is best to remove these
+bodies, even when present in small proportions, provided it can be done
+without altering the character of the proteid bodies. This is secured
+by extracting the fine-ground vegetable material first with petroleum
+ether, and afterwards with strong alcohol and ether. Practically, all
+of the fatty bodies and the greater part of the most objectionable
+coloring matters are removed by this treatment. The extraction should
+in all cases be made at low temperatures, not exceeding 35°, to avoid
+the coagulating effect of higher temperatures upon the albuminous
+bodies which may be present.
+<span class="pagenum"><a id="Page_433"></a>[Pg 433]</span></p>
+
+<p>In this laboratory, fatty seeds, as for instance peanuts, are first
+ground into coarse meal, then extracted with petroleum ether, ground
+to a fine meal and the fat extraction completed with petroleum ether,
+ninety-five per cent alcohol and pure sulfuric ether. The residue of
+the last solvent may be removed by aspirating air through the extracted
+meal. In some cases, it is advisable to extract with ethyl ether before
+as well as after the alcoholic extraction. This treatment removes at
+least a part of the water and prevents the dilution of the first part
+of alcohol added to such an extent as to make it dissolve some of the
+proteid matters. In each case, a portion of the alcoholic extract
+should be tested qualitively for proteid matter. If any be found,
+stronger alcohol should be used for, at least, the first extraction. A
+portion of the meal, prepared as above directed, is extracted with a
+ten per cent solution of sodium chlorid, as described further on, and a
+measured portion of the filtered extract diluted with water until the
+proteid matter in solution begins to be precipitated. By this treatment
+the proper strength of the salt solution, to be used for the subsequent
+extraction, is determined. To save time in dialyzing, the solution of
+salt employed as a solvent should be as dilute as possible.</p>
+
+<p>The mixture of meal and solvent sometimes filters with difficulty.
+In these cases, it is advisable to first pour it into a linen bag
+from which the liquid portion can be removed by gentle pressure and
+subsequently filtered through paper. As a last resort, the liquid
+secured from the linen filter can be saturated with ammonium, zinc or
+magnesium sulfate, whereby all the proteid matters are thrown out.
+After filtering, the residue is again dissolved in salt solution and
+can then be readily filtered through paper.</p>
+
+<p>The clear filtrate should be tested by fractional precipitation by heat
+and the final filtrate by acetic acid, as will be described further on.</p>
+
+<p>The proteid matter may be further freed from amid compounds by
+treatment with copper sulfate.<a id="FNanchor_365" href="#Footnote_365" class="fnanchor">[365]</a>
+This treatment is not advisable, however, except for the purpose of
+determining the total proteid nitrogen in the sample. The action of the
+<span class="pagenum"><a id="Page_434"></a>[Pg 434]</span>
+water, heat and cupric sulfate combined is capable of inducing grave
+changes in the character of the residual matter which would seriously
+interfere with the results of subsequent studies of the nature of the
+proteid bodies.</p>
+
+<p>In many instances, as with cereal grains, the separation of the proteid
+bodies is accomplished by no further preliminary treatment than is
+necessary to reduce them to the proper degree of fineness.</p>
+
+<p><b>393. Diversity of Character.</b>—The proteids which occur in
+vegetable products are found in all parts of the tissues of the plants,
+but in cereals especially in the seeds. In grass crops and in some
+of the legumes, such as clover, the nitrogenous matters are chiefly
+found in the straw and leaves. The general classification of these
+bodies has already been given, but each kind of plant presents marked
+variations, not only in the relative proportions of the different
+classes, but also in variations in the nature of each class. For this
+reason the study of vegetable proteids is, in some respects, a new
+research for each kind of plant examined. There are, however, some
+general principles which the analyst must follow in his work, and an
+attempt will be made here to establish these and to construct thereon
+a rational method of conducting the investigation. In the separation
+and estimation of complex bodies so nearly related to each other, it is
+difficult not only to secure satisfactory results, but also to prevent
+the transformation of some forms of proteid matter into others nearly
+related thereto by the action of the solvents used for separation and
+precipitation.</p>
+
+<p><b>394. Separation of Gluten from Wheat Flour.</b>—The most important
+proteid in wheat is the body known as gluten, a commercial name given
+to the nitrogenous matters insoluble in cold water. The gluten thus
+obtained does not represent a single chemical compound, but is a
+complex consisting of at least two proteid bodies, which together form
+an elastic, pasty mass, insoluble in cold water containing a trace
+of mineral salts. This mass has the property of holding mechanically
+entangled among its particles bubbles of gas, which, expanding under
+the action of heat during cooking, give to bread made of glutenous
+flours its porous property.
+<span class="pagenum"><a id="Page_435"></a>[Pg 435]</span></p>
+
+<p>In respect of proteids, the American wheats, as a rule, are quite
+equal to those of foreign origin. This is an important characteristic
+when it is remembered that both the milling and food values of a wheat
+depend largely on the nitrogenous matter which is present. It must
+not be forgotten, however, that merely a high percentage of proteids
+is not always a sure indication of the milling value of a wheat. The
+percentage of gluten to the other proteid constituents of a wheat is
+not always constant, and it is the gluten content of a flour on which
+its bread making qualities chiefly depend. The percentage of moist
+gluten gives, in a rough way, the property of the glutenous matter of
+absorbing and holding water under conditions as nearly constant as
+can be obtained. In general, it may be said that the ratio between
+the moist gluten and the dry gluten in a given sample is an index for
+comparison with other substances in the same sample. Upon the whole,
+however, the percentage of dry gluten must be regarded as the safer
+index of quality. In respect of the content of glutenous matter, our
+domestic wheats are distinctly superior to those of foreign origin.
+They are even better than the Canadian wheats in this respect. It may
+be fairly inferred, therefore, that while our domestic wheats give a
+flour slightly inferior in nutritive properties to that derived from
+foreign samples, it is nevertheless better adapted for baking purposes,
+and this quality more than compensates for its slight deficiency in
+respect of nutrition, a deficiency, which, however, is so minute as to
+be hardly worth considering.<a id="FNanchor_366" href="#Footnote_366" class="fnanchor">[366]</a></p>
+
+<p>The gluten is separated in this laboratory from the other constituents
+of a flour by the following process:</p>
+
+<p>Ten grams of the fine-ground flour are placed in a porcelain dish, well
+wet with nearly an equal weight of water at a temperature of not to
+exceed 15°, and the mass worked into a ball with a spatula, taking care
+that none of it adheres to the walls of the dish. The ball of dough is
+allowed to stand for an hour, at the end of which time it is held in
+the hand and kneaded in a stream of cold water until the starch and
+soluble matter are removed. The ball of gluten thus obtained is placed
+in cold water and allowed to remain for an hour when it is removed,
+pressed as dry as possible between the hands, rolled into a ball,
+<span class="pagenum"><a id="Page_436"></a>[Pg 436]</span>
+placed in a flat bottom dish and weighed. The weight obtained is
+entered as moist gluten. The dish containing the ball of gluten is
+dried for twenty hours in a steam-bath, again weighed, and the weight
+of material obtained entered as dry gluten. The determination of dry
+and moist gluten cannot in any sense be regarded as an isolation and
+estimation of a definite chemical compound. For millers’ and bakers’
+purposes, however, the numbers thus obtained have a high practical
+value. A typical wheat grown in this country will contain about 26.50
+per cent of moist and 10.25 per cent of dry gluten.</p>
+
+<p>The gluten of wheat is composed of two proteid bodies, gliadin and
+glutenin.<a id="FNanchor_367" href="#Footnote_367" class="fnanchor">[367]</a>
+Gliadin contains 17.66 per cent, and glutenin 17.49 per cent of
+nitrogen. Gliadin forms a sticky mass when mixed with water and is
+prevented from passing into solution by the small content of mineral
+salts present in the flour. It serves to bind together the other
+ingredients of the flour, thus rendering the dough tough and coherent.
+Glutenin serves to fix the gliadin and thus to make it firm and solid.
+Glutenin alone cannot yield gluten in the absence of gliadin, nor
+gliadin without the help of glutenin. Soluble metallic salts are also
+necessary to the formation of gluten, and act as suggested above, by
+preventing the solution of the gliadin in water, during the process of
+washing out the starch. No fermentation takes place in the formation of
+gluten from the ingredients named.</p>
+
+<p>The gluten, which is obtained in an impure state by the process above
+described, is, therefore, not to be regarded as existing as such in the
+wheat kernel or flour made therefrom, but to arise by a union of its
+elements by the action of water.</p>
+
+<p><b>395. Extraction with Water.</b>—It is quite impossible to get an
+extract from fine-ground vegetable matter in pure water because the
+soluble salts of the sample pass at once into solution and then a pure
+water solvent becomes an extremely dilute saline solution. The aqueous
+extract may, however, be subjected to dialysis, whereby the saline
+matter is removed and the proteid matter, not precipitated during the
+dialytic process, may be regarded as that part of it in the original
+sample soluble in pure water. Nevertheless, in many instances, it is
+<span class="pagenum"><a id="Page_437"></a>[Pg 437]</span>
+important to obtain an extract with cold water. In oatmeal the
+aqueous extract is obtained by Osborne as follows:<a id="FNanchor_368" href="#Footnote_368" class="fnanchor">[368]</a>
+Five pounds of fine-ground meal are shaken occasionally with six liters
+of cold water for twenty-four hours, the liquid removed by filtration
+and pressure and the extraction continued with another equal portion
+of water in the manner noted. The two liquid extracts are united and
+saturated with commercial ammonium sulfate which precipitates all
+the dissolved proteid matter. The filtrate obtained is collected on
+a filter, washed with a saturated solution of ammonium sulfate and
+removed as completely as possible from the filter paper by means of
+a spatula. Any residual precipitate remaining on the paper is washed
+into the vessel containing the removed precipitate and the undissolved
+precipitate well beaten up in the liquid, which is placed in a dialyzer
+with a little thymol, to prevent fermentation, and subjected to
+dialysis for about two weeks. At the end of that time, the contents
+of the dialyzer are practically free of sulfates. The contents of the
+dialyzers are then thrown on a filter and in the filtrate are found
+those proteids first extracted with water, precipitated with ammonium
+sulfate and redissolved from this precipitated state by pure water. In
+the case of oatmeal, this proteid matter is not coagulated by heat, and
+may be obtained in the dry state by the evaporation of the filtrate
+last mentioned at a low temperature in vacuo. It is evident that the
+character of the proteid matter thus obtained will vary with the nature
+of the substance examined. In the case of oats, it appears to be a
+proteose and not an albumin.</p>
+
+<p><b>396. Action of Water on Composition of Proteids.</b>—When a
+body, such as oatmeal, containing many proteids of nearly related
+character, is exposed to the action of a large excess of water, the
+proteid bodies may undergo important changes whereby their relations
+to solvents are changed. After oatmeal has been extracted with water,
+as described above, the proteid matter originally soluble in dilute
+alcohol undergoes an alteration and assumes different properties. The
+same remark is applicable to the proteid body soluble in dilute potash.
+Nearly all the proteid matter of oatmeal is soluble in dilute potash, if
+<span class="pagenum"><a id="Page_438"></a>[Pg 438]</span>
+this solvent be applied directly, but if the sample be previously
+treated with water or a ten per cent salt solution the subsequent
+proportion of proteid matter soluble in dilute potash is greatly
+diminished.<a id="FNanchor_369" href="#Footnote_369" class="fnanchor">[369]</a>
+Water applied directly to the oatmeal apparently dissolves an acid
+albumin, a globulin or globulins, and a proteose. The bodies, however,
+soluble in water, exist only in small quantities in oatmeal. Experience
+has shown that in most instances, it is safer to begin the extraction
+of a cereal for proteid matter with a dilute salt solution rather than
+with water, and to determine the matters soluble in water alone by
+subsequent dialysis.</p>
+
+<p><b>397. Extraction with Dilute Salt Solution.</b>—In general, it
+is advisable to begin the work of separating vegetable proteids by
+extracting the sample with a dilute brine usually of ten per cent
+strength. As conducted by Osborne and Voorhees, on wheat flour, the
+manipulation is carried on as follows:<a id="FNanchor_370" href="#Footnote_370" class="fnanchor">[370]</a></p>
+
+<p>The fine-ground whole wheat flour, about four kilograms, is shaken with
+twice that weight of a ten per cent sodium chlorid solution, strained
+through a sieve, to break up lumps, and allowed to settle for sixteen
+hours. At the end of this time, about half of the supernatant liquid
+is removed by a siphon or by decantation and filtered. Two liters
+more of the salt solution are added, the mixture well stirred and the
+whole brought onto the filter used above. The filtrate is collected
+in successive convenient portions and each portion, as soon as it is
+obtained, is saturated with ammonium sulfate. All the proteid matter is
+precipitated by this reagent. The precipitate is collected on a filter,
+redissolved in a convenient quantity of the salt solution and dialyzed
+for fourteen days or until all sulfates and chlorids are removed. The
+proteid matter, which is separated on dialysis, in this instance, is a
+globulin.</p>
+
+<p>The proteid matter not precipitated on dialysis is assumed to be that
+part of the original substance soluble in water.</p>
+
+<p>A part of the water soluble proteid matter obtained as above is
+coagulated by heat at from 50° to 80°. The part not separated by heat
+gives a precipitate on saturation with sodium chlorid.</p>
+
+<p>In wheat there are found soluble in water two albumins and a
+proteose.<a id="FNanchor_371" href="#Footnote_371" class="fnanchor">[371]</a></p>
+
+<p><span class="pagenum"><a id="Page_439"></a>[Pg 439]</span>
+In separating the albumin coagulating at a low boiling point from the
+dialyzed solution mentioned above, it is heated to 60° for an hour,
+the precipitate collected on a gooch, washed with hot water (60°), and
+then successively with ninety-five per cent alcohol, water-free alcohol
+and ether. On drying the residual voluminous matter on the filter over
+sulfuric acid, it becomes dense and horny, having in an ash free state,
+according to Osborne, the following composition:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdr">Per cent.</td>
+   </tr><tr>
+      <td class="tdl">Carbon</td>
+      <td class="tdc">53.06</td>
+   </tr><tr>
+      <td class="tdl">Hydrogen<span class="ws3">&nbsp;</span></td>
+      <td class="tdc">&#8199;6.82</td>
+   </tr><tr>
+      <td class="tdl">Nitrogen</td>
+      <td class="tdc">17.01</td>
+   </tr><tr>
+      <td class="tdl">Sulfur</td>
+      <td class="tdc">&#8199;1.30</td>
+   </tr><tr>
+      <td class="tdl">Oxygen</td>
+      <td class="tdc">21.81</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>398. Treatment without Precipitation with Ammonium
+Sulfate.</b>—Where abundant means are at hand for dialyzing large
+volumes of solution, the preliminary treatment of the solution made
+with ten per cent sodium chlorid with ammonium sulfate may be omitted.</p>
+
+<p>When the precipitated proteids are to be used for the estimation of
+the nitrogen therein contained, it has been proposed to substitute
+the corresponding zinc salt for the ammonium sulfate.<a id="FNanchor_372" href="#Footnote_372" class="fnanchor">[372]</a>
+This reagent has given satisfactory results in this laboratory and while
+a larger experience is desirable before commending it as an acceptable
+substitute in all cases, yet its obvious advantage, in being free of
+nitrogen for the use mentioned, entitles it to careful consideration.</p>
+
+<p>The manipulation, with the exception of the precipitation with ammonium
+sulfate, is the same as that described in the preceding paragraph. The
+globulins are completely precipitated when the dialysis is complete and
+may be separated from the soluble albumins and proteoses by filtration.</p>
+
+<p id="P_399"><b>399. Separation of the Bodies Soluble in
+Water.</b>—<i>Albumins.</i>—By the methods of treatment just
+described, the proteid matters soluble in ten per cent sodium chlorid
+solution are separated into two classes, <i>viz.</i>, globulins
+insoluble in pure water and albumins and proteoses soluble in pure
+water. The aqueous solution will also contain any amids or nitrogenous
+<span class="pagenum"><a id="Page_440"></a>[Pg 440]</span>
+bases soluble in the dilute saline solution and in water. Osborne and
+Voorhees have found that the best way of separating the albumins in
+the pure aqueous solution is by the application of heat.<a id="FNanchor_373" href="#Footnote_373" class="fnanchor">[373]</a>
+By means of a fractional coagulation the albumins are divided into classes,
+<i>viz.</i>, those separating at from 60° to 65° and those remaining in
+solution at that temperature but separating up to 85°. The respective
+quantities of these albumins are determined by collecting them in a
+filter and estimating the nitrogen therein by moist combustion in the
+usual way. Even a larger number of albumins may be secured, as in the
+maize kernel, by such a fractional precipitation by means of heat.
+Chittenden and Osborne find in this instance that the precipitation
+begins at about 40°.<a id="FNanchor_374" href="#Footnote_374" class="fnanchor">[374]</a></p>
+
+<p><i>Proteose.</i>—After the separation of the albumins by heat the
+filtrate may still contain proteid matter. This matter belongs to
+the proteose class. It may be partially secured by concentrating the
+filtrate, after the removal of the albumins, to a small bulk when a
+part of the proteose body will separate. It may be thrown out entirely
+by treating the filtrate above mentioned with fine-ground salt until it
+is saturated or by adding salt until the solution contains about twenty
+per cent thereof and precipitating the proteose by acetic acid.<a id="FNanchor_375" href="#Footnote_375" class="fnanchor">[375]</a></p>
+
+<p><b>400. Separation of the Globulins.</b>—The globulins which are
+extracted with ten per cent solution of sodium chlorid and precipitated
+on dialysis may be separated by fractional solution into several
+bodies of nearly related properties. This solution is conveniently
+accomplished by saline solvents of increasing strength. In the case of
+the maize globulins, Chittenden and Osborne employ dilute solutions of
+common salt for effecting the separation, beginning with a quarter of a
+per cent and ending with a two per cent mixture.<a id="FNanchor_376" href="#Footnote_376" class="fnanchor">[376]</a></p>
+
+<p><b>401. Proteids Soluble in Dilute Alcohol.</b>—Some of the proteid
+bodies which are soluble in dilute salt solution and in water are also
+soluble in alcohol. Since these bodies are more easily identified
+by the processes already described, attention will be given in this
+paragraph solely to those proteid bodies which are insoluble in water
+or dilute salt solution and are soluble in dilute alcohol.
+<span class="pagenum"><a id="Page_441"></a>[Pg 441]</span></p>
+
+<p>For the extraction of these bodies, the residue, left after extraction
+with a ten per cent solution of sodium chlorid or with water, is
+mixed with enough strong alcohol to secure by the admixture with the
+water present in the sample an alcohol of about seventy-five per cent
+strength. The mixture is well shaken and digested for some time, at a
+temperature of about 46°, and thrown on a filter which is kept at about
+the same temperature. The residue is again mixed with alcohol of the
+same strength (seventy-five per cent) using about four liters for two
+and a half kilos of the original material. During the second digestion
+the temperature is kept at about 60°. The latter operation is repeated
+three times and in each case the filtrate obtained is evaporated
+separately.<a id="FNanchor_377" href="#Footnote_377" class="fnanchor">[377]</a>
+This process is especially applicable to the meal from maize kernels,
+which contains a high relative percentage of an alcohol soluble
+proteid, zein.</p>
+
+<p>The chief part of the zein is found in the first two extracts, obtained
+as described above. On evaporation, the zein separates as a tough,
+leathery, yellow-colored mass on the walls of the containing vessel. It
+is cut into small pieces and digested for several days in cold, pure
+alcohol. This is followed by digestion with a mixture of ether and
+pure alcohol, and finally with pure ether. By this treatment a part of
+the zein becomes insoluble in seventy-five per cent alcohol. The part
+soluble in dilute alcohol is precipitated by pouring it into water.</p>
+
+<p>Another method of preparing zein is to extract the meal with
+seventy-five per cent alcohol after it has been treated with a ten per
+cent salt solution.</p>
+
+<p>In this case the extraction is continued with seventy-five per cent
+alcohol in successive portions until no more proteid matter passes
+into solution. The several extracts are united and the alcohol removed
+by distillation, by which process the zein is separated. It is washed
+with distilled water, until the sodium chlorid is removed, dissolved in
+warm alcohol of about eighty per cent strength and any insoluble matter
+removed by filtration. On evaporating the filtrate nearly to dryness,
+the zein is separated and pressed as free of water as possible,
+yielding a yellow, elastic substance resembling molasses candy. This
+preparation is purified by digestion with pure alcohol and ether in the
+<span class="pagenum"><a id="Page_442"></a>[Pg 442]</span>
+manner described. The two zeins which are secured by the treatment, one
+soluble and the other insoluble in alcohol, are practically identical
+in composition.<a id="FNanchor_378" href="#Footnote_378" class="fnanchor">[378]</a></p>
+
+<p>Zein freshly precipitated by pouring its alcoholic solution in water
+is wholly insoluble in water, and, on boiling therewith, is changed
+into the variety insoluble in dilute alcohol. Boiled with dilute
+sulfuric acid, six in 300 cubic centimeters of water, it melts, forming
+a gummy mass, which is very slowly attacked by the acid yielding
+proteoses and peptones. Heated with stronger sulfuric acid it undergoes
+decomposition, yielding leucin, tyrosin, and glutamic acid.</p>
+
+<p><b>402. Solvent Action of Acids and Alkalies.</b>—In the preceding
+paragraphs, a synopsis has been given of the methods of separating
+proteid matters in such a manner as to secure them in a pure state in
+the same conditions as they exist in the natural substances. A very
+large percentage of the proteid matter is still left undissolved after
+extraction with the solvents already mentioned.</p>
+
+<p>Often important information may be gained concerning the nature of the
+residual proteid matters by fractional extraction with dilute acids
+and alkalies. When the strength of these solutions is such that they
+contain about one per cent of the acid or alkali, the whole of the
+proteid matter may be dissolved by boiling successively with acid and
+alkali for half an hour. The proteid matter passing into solution in
+these cases is usually changed in character, assuming the nature of
+proteoses or allied bodies, when treated with an acid, and becoming
+albuminates when boiled with an alkali. Easily soluble carbohydrate
+matter is also removed by this treatment so that the residue obtained
+consists largely of cellulose and is known as crude or insoluble fiber.
+The removal of all the bodies soluble in dilute boiling acid and alkali
+is accomplished by the method described in paragraph <b><a href="#P_272">272</a></b>.</p>
+
+<p>For research purposes, the solvent action of dilute alkali is of chief
+importance to the analyst, and the extraction of the proteid matter,
+after all that is soluble in water, common salt solution and alcohol
+<span class="pagenum"><a id="Page_443"></a>[Pg 443]</span>
+has been removed, should commence with a solution of potassium or
+sodium hydroxid containing not over two-tenths per cent of the alkali.</p>
+
+<p>It has been shown by Osborne that the solvent action of very dilute
+alkali, in the cold, may be exerted without changing the character of
+the dissolved proteid.<a id="FNanchor_379" href="#Footnote_379" class="fnanchor">[379]</a></p>
+
+<p><b>403. Method of Extraction.</b>—The solvent employed is usually
+a two-tenths per cent solution of potassium hydroxid. It may be
+added directly to the substance or may follow extraction with water,
+salt solution or alcohol. In the former case, the manipulation
+is illustrated by the following description of the treatment of
+oatmeal:<a id="FNanchor_380" href="#Footnote_380" class="fnanchor">[380]</a></p>
+
+<p>One hundred grams of oatmeal are mixed with half a liter of a
+two-tenths per cent potassium hydroxid solution and allowed to stand
+for some time at room temperature. The mixture is strained through
+a cloth to remove the chaff and the residue is stirred with another
+small portion of the solvent, again strained in the same cloth and the
+residue squeezed dry. The strained liquids are united and enough more
+of the solvent added to make the volume 700 cubic centimeters. After
+standing for some time, the insoluble matter settles to the bottom of
+the vessel and the supernatant liquid is decanted. More solvent is
+added to the residue, well mixed therewith and treated as above. It is
+advisable to make a third extraction in the same way. The extracts are
+united, passed through a filter, the proteid matter in solution thrown
+out by acetic acid, washed with water, alcohol and ether and dried over
+sulfuric acid.</p>
+
+<p>The methods of procedure, when the sample has been previously extracted
+with water, salt solution or alcohol, are essentially the same as that
+just described and the reader may consult the paper of Osborne for
+details.<a id="FNanchor_381" href="#Footnote_381" class="fnanchor">[381]</a></p>
+
+<p><b>404. Methods of Drying Separated Proteids.</b>—In the preceding
+paragraphs, the analyst has been directed, in most instances, to
+dry the proteid matter, after it is secured in as pure a form as
+possible, at room temperature, over sulfuric acid. By this treatment
+the preparation may be obtained in a form suited to the study of its
+physical properties, since its solubility has not been affected by
+<span class="pagenum"><a id="Page_444"></a>[Pg 444]</span>
+subjecting it to a high temperature. When it is desired to use the
+sample only for chemical analysis it is not necessary to wait on the
+slow process above mentioned. In this case the sample may be dried in
+an inert atmosphere at the temperature of a steam-bath or even at 110°.
+It is better, however, to avoid so high a temperature and to conduct
+the desiccation in vacuo at a heat not above that of boiling water. The
+sample, before drying, should be reduced to the finest possible state
+of comminution, otherwise particles of aqueous vapor may be retained
+with great tenacity.</p>
+
+<p>In many cases it is advisable to dry the sample pretty thoroughly, then
+grind to a fine powder and finish the desiccation with the pulverulent
+mass. This treatment can be followed when the quantity of the material
+is considerably in excess of that required for the analytical
+operations.</p>
+
+<p><b>405. Determination of Ash.</b>—No method of treatment is known
+by means of which vegetable proteid matters may be obtained entirely
+free of mineral matters. The mineral bases may be naturally present
+in the proteid matter as organic and inorganic salts, or they may be
+mechanically entangled therewith, having been derived either from
+the other tissues of the plant or from the solvents employed. It is
+necessary in calculating the analytical data to base the computation on
+the ash free substance. The percentage of ash is determined by any of
+the standard processes or by heating the sample in a combustion tube,
+to very low redness, in a current of oxygen. The total residue obtained
+is used in calculating the percentage of ash, and the weights of
+material subsequently used for the determination of carbon, hydrogen,
+nitrogen and sulfur are corrected for the calculations by deducting the
+quantity of mineral matter contained therein.</p>
+
+<p>By reason of the highly hygroscopic nature of the dry proteid bodies,
+they must be kept over a desiccating material and weighed quickly on a
+balance, in an atmosphere which is kept free of moisture by the usual methods.</p>
+
+<p><b>406. Carbon and Hydrogen.</b>—Carbon and hydrogen are estimated in
+proteid matters by combustion with copper oxid. Osborne prefers to burn
+the sample in a platinum boat in a current of air or of oxygen free of
+<span class="pagenum"><a id="Page_445"></a>[Pg 445]</span>
+moisture and carbon dioxid.<a id="FNanchor_382" href="#Footnote_382" class="fnanchor">[382]</a>
+It is advisable to use also a layer of lead chromate in addition to
+the copper oxid and metallic copper. The method of conducting the
+combustion has already been described.<a id="FNanchor_383" href="#Footnote_383" class="fnanchor">[383]</a>
+The analyst should have at his disposal a quantity of pure sugar, which
+may be used from time to time in testing the accuracy of the work.
+In beginning a series of combustions this precaution should never be
+omitted. The addition of the lead chromate is to make more certain the
+absorption of oxidized sulfur produced during the combustion.</p>
+
+<p id="P_407"><b>407. Estimation of Nitrogen.</b>—In most cases it is found
+convenient, during the progress of separating vegetable proteids, to
+determine the quantity of each kind by estimating the nitrogen by moist
+combustion and computing the quantity of proteid matter by multiplying
+the nitrogen by 6.25. The estimation of the nitrogen is made either on
+an aliquot part of the extract or by direct treatment of the residue.</p>
+
+<p>In the pure extracted proteid matter the nitrogen is most conveniently
+determined by moist combustion, but it may also be obtained either by
+combustion with soda-lime or with copper oxid, or by other reliable
+methods.<a id="FNanchor_384" href="#Footnote_384" class="fnanchor">[384]</a></p>
+
+<p>The percentages of nitrogen found in the principal proteid bodies,
+together with the factors for computing the weights of the proteid
+bodies from the weights of nitrogen found, are given below:</p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb">&nbsp; Name of body. &nbsp;</th>
+      <th class="tdc bb">&nbsp;Percentage of nitrogen.&nbsp;</th>
+      <th class="tdc bb">Factor.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Mucin</td>
+      <td class="tdl_ws1">13.80 to 14.13</td>
+      <td class="tdl_ws1">7.25 to 7.08</td>
+   </tr><tr>
+      <td class="tdl">Chondrin</td>
+      <td class="tdl_ws1">14.20 to 14.65</td>
+      <td class="tdl_ws1">7.04 to 6.83</td>
+   </tr><tr>
+      <td class="tdl">Albuminates</td>
+      <td class="tdl_ws1">13.87</td>
+      <td class="tdl_ws1">7.21</td>
+   </tr><tr>
+      <td class="tdl">Oat proteids</td>
+      <td class="tdl_ws1">15.85</td>
+      <td class="tdl_ws1">6.31</td>
+   </tr><tr>
+      <td class="tdl">Serum globulin</td>
+      <td class="tdl_ws1">15.63</td>
+      <td class="tdl_ws1">6.40</td>
+   </tr><tr>
+      <td class="tdl">Egg albumin</td>
+      <td class="tdl_ws1">15.71 to 17.85</td>
+      <td class="tdl_ws1">6.37 to 5.60</td>
+   </tr><tr>
+      <td class="tdl">Maize proteids</td>
+      <td class="tdl_ws1">16.06</td>
+      <td class="tdl_ws1">6.22</td>
+   </tr><tr>
+      <td class="tdl">Casein</td>
+      <td class="tdl_ws1">15.41 to 16.29</td>
+      <td class="tdl_ws1">6.49 to 6.13</td>
+   </tr><tr>
+      <td class="tdl">Serum albumin</td>
+      <td class="tdl_ws1">15.96</td>
+      <td class="tdl_ws1">6.27</td>
+   </tr><tr>
+      <td class="tdl">Syntonin</td>
+      <td class="tdl_ws1">16.10</td>
+      <td class="tdl_ws1">6.21</td>
+   </tr><tr>
+      <td class="tdl">Keratin</td>
+      <td class="tdl_ws1">16.20 to 17.70</td>
+      <td class="tdl_ws1">6.17 to 5.65</td>
+   </tr><tr>
+      <td class="tdl">Fibrinogen</td>
+      <td class="tdl_ws1">16.65</td>
+      <td class="tdl_ws1">6.01</td>
+   </tr><tr>
+      <td class="tdl">Peptones</td>
+      <td class="tdl_ws1">16.66 to 17.13</td>
+      <td class="tdl_ws1">6.00 to 5.84</td>
+   </tr><tr>
+      <td class="tdl">Elastin</td>
+      <td class="tdl_ws1">16.75</td>
+      <td class="tdl_ws1">5.97</td>
+   </tr><tr>
+      <td class="tdl">Wheat proteids</td>
+      <td class="tdl_ws1">16.80 to 18.39</td>
+      <td class="tdl_ws1">5.95 to 5.44</td>
+   </tr><tr>
+      <td class="tdl">Fibrin</td>
+      <td class="tdl_ws1">16.91</td>
+      <td class="tdl_ws1">5.91</td>
+   </tr><tr>
+      <td class="tdl">Flax seed proteids</td>
+      <td class="tdl_ws1">17.70 to 18.78</td>
+      <td class="tdl_ws1">5.65 to 5.33</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_446"></a>[Pg 446]</span>
+<b>408. Determination of Sulfur.</b>—Sulfur is a characteristic
+constituent of the proteid bodies, existing in quantities approximating
+one per cent of their weight.</p>
+
+<p>In the estimation of sulfur, it is first converted into sulfuric acid,
+which is thrown out by a soluble barium salt and the sulfur finally
+weighed as barium sulfate.</p>
+
+<p>All the sulfur existing in the organic state in a proteid may be
+obtained by burning in a current of oxygen and conducting the gaseous
+products of combustion through solid sodium or potassium carbonate
+at or near a red heat.<a id="FNanchor_385" href="#Footnote_385" class="fnanchor">[385]</a>
+The organic sulfur may also be converted into sulfuric acid by fusing
+the proteid body with a mixture of sodium hydroxid and potassium
+nitrate. The fused mass, after cooling, is dissolved in water, the
+solution acidified with hydrochloric, evaporated to dryness to
+decompose nitrates and remove excess of hydrochloric acid and dissolved
+in a large excess of water. After standing for a day, the solution is
+filtered and the sulfuric acid thrown out of the hot filtrate with a
+slight excess of barium chlorid solution. The usual precautions in
+precipitating, filtering and igniting the barium sulfate are to be
+observed.<a id="FNanchor_386" href="#Footnote_386" class="fnanchor">[386]</a></p>
+
+<p><b>409. General Observations.</b>—In the preceding paragraphs have
+been stated the general principles upon which the separation of
+vegetable proteid matters depends, and a description has been given
+of the several processes by which this separation is accomplished. In
+each case, however, special conditions exist which require special
+modifications of the general processes, and these can only be
+successfully secured by the skill, judgment and patient labor of the
+investigator. Many of these cases have been already worked out, and the
+valuable data secured by Chittenden, Osborne and others, are accessible
+to the analyst in the papers already cited. In the case of the proteids
+in the peanut, a similar work has been done in this laboratory by
+Bigelow, the data of which have not yet been published. It is only
+by a careful study of the work already done as outlined here and as
+published in full in the cited papers, that the analyst will be able to
+secure trustworthy guidance for future investigations.
+<span class="pagenum"><a id="Page_447"></a>[Pg 447]</span></p>
+
+<p><b>410. Dialysis.</b>—One of the most important of the operations
+connected with the separation and analysis of proteids is the removal
+of the salts whereby their solutions are secured. This is accomplished
+by subjecting the solutions of the proteid matters to dialysis. The
+solution is placed in bags made of parchment dialysis paper. These
+bags are tied about a glass tube, whereby access may be had to their
+contents during the progress of the work. Since the volume of the
+liquid increases during the process, the bags should not be filled too
+full in the beginning.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_105" src="images/fig105.jpg" alt="" width="600" height="369" >
+    <p class="center spb1">Fig. 105. Dialyzing Apparatus.</p>
+</div>
+
+<p>In this laboratory the dialysis is carried out by Bigelow with the
+city water from the Potomac, which is first passed through a battery
+of porous porcelain filtering tubes to remove any suspended silt or
+micro-organisms. If unfiltered water be used, the germs therein cause
+a fermentation in the proteid matter, which seriously interferes with
+the value of the data obtained, and which can only be avoided by the
+use of an antiseptic, such as an alcoholic solution of thymol. Even
+with filtered water, the use of a few drops of the solution mentioned
+is often necessary. To avoid the use of too great quantities of the
+filtered water, the dialyzers are arranged <i>en batterie</i>, as shown
+in the <a href="#FIG_105">figure</a>. The filtered water enters the first vessel and thence
+<span class="pagenum"><a id="Page_448"></a>[Pg 448]</span>
+passes through all. The parchment bags are frequently changed from
+vessel to vessel, each being brought successively into the first vessel
+in contact with the fresh water. In some cases the final steps in the
+dialysis may be accomplished in distilled water.</p>
+
+<p>It is advisable to conduct a fractional preliminary dialysis of the
+salt solution containing proteids in such a way as to secure the
+globulins precipitated in each interval of twenty-four hours. Each
+portion thus secured may be examined with the microscope. Usually a
+period of two weeks is required to entirely remove the mineral salts
+from solution. If prepared parchment tubes be used for the dialysis,
+they should be first tested for leaks, and should not be more than half
+filled. By the use of a large number of these tubes a greater surface
+is exposed to dialytic action, and the time required to complete the
+operation is correspondingly decreased.</p>
+
+<h3>SEPARATION AND ESTIMATION OF<br> NITROGENOUS BODIES IN ANIMAL PRODUCTS.</h3>
+
+<p id="P_411"><b>411. Preparation of the Sample.</b>—Animal products present many
+difficulties in respect of the reduction thereof to a sufficiently
+comminuted condition for analytical examination. In the case of bones,
+the choppers used for preparing them for feeding to fowls are the most
+efficient apparatus for reducing them to fragments. In this condition
+they may be ground to a finer state in a sausage machine. The flesh of
+animals may be reduced by this machine, with two or three grindings,
+to a fairly homogeneous mass. Subsequent grinding in a mortar with
+powdered glass or sharp sand may serve to reduce the sample to a finer
+pulp, but is not usually necessary and should be avoided when possible.
+The sample thus prepared serves for the estimation of water, ash
+and fat by methods already described. The sample should be prepared
+in quantities of considerable magnitude, the whole of any organ or
+separate portion of the body being used when possible. In examining the
+whole body the relative weights of blood, bones, viscera, muscle, hide
+and other parts should first of all be ascertained and noted.</p>
+
+<p><b>412. Treatment of Muscular Tissues for Nitrogenous Bodies.</b>—For
+<span class="pagenum"><a id="Page_449"></a>[Pg 449]</span>
+the present purpose a brief sketch of the method of separating the
+nitrogenous bodies in the muscular tissues of the body is all that
+can be attempted. For methods of examining the different organs and
+parts of the body in greater detail, standard works on physiological
+chemistry may be consulted.<a id="FNanchor_387" href="#Footnote_387" class="fnanchor">[387]</a></p>
+
+<p><i>Extraction with Cold Water.</i>—A noted quantity of the finely
+divided tissues is mixed with several volumes of ice cold water and
+well rubbed occasionally for several hours, the temperature meanwhile
+being kept low. The mixture is poured into a linen bag and the liquid
+portion removed by gentle pressure. The residue in like manner is
+treated with fresh portions of cold water until it gives up no further
+soluble matters. An aliquot portion of the extract is concentrated
+to a small bulk and serves for the determination of total nitrogen.
+The methods of separating and estimating nitrogenous bodies in flesh
+soluble in water will be given in considerable detail further on.</p>
+
+<p><i>Extraction with Ammonium Chlorid and Hydrochloric Acid.</i>—The
+residue, after exhaustion with cold water, is extracted with a solution
+of ammonium chlorid containing 150 grams of the salt in a liter. This
+method of extraction is entirely similar to that with water just
+described. Globulins and myosin pass into solution by this treatment.
+The residual mass is washed as free as possible of the solvent and
+is then further extracted with dilute hydrochloric acid containing
+four cubic centimeters of the fuming acid in a liter. The treatment
+with dilute acid is continued until no further substance passes
+into solution. This is determined by neutralizing a portion of the
+extract with sodium carbonate, or by the direct addition of potassium
+ferrocyanid. In either case absence of a precipitate indicates that no
+nitrogenous matters are present in the solution.</p>
+
+<p><i>Extraction with Alkali.</i>—The residue from the acid extraction
+is washed with water until the acid is removed and then extracted in a
+similar manner with a dilute solution of sodium or potassium hydroxid
+containing not to exceed two grams of the caustic to the liter. When
+this residue is finally washed with water and a little acetic acid,
+it will be found that practically all the purely albuminous bodies
+contained in the tissues have been extracted with the exception of any
+<span class="pagenum"><a id="Page_450"></a>[Pg 450]</span>
+fibrin, which the blood, present in the tissues at the commencement of
+the extraction, may have contained. The extract should be acidified
+with acetic as soon as obtained.</p>
+
+<p><i>Extraction with Boiling Water.</i>—The residual matter boiled
+for some time with water will part with its collagen, which, when
+transformed by the heat into glutin, passes into solution.</p>
+
+<p>The sarcolemma, membranes, elastic fibers and keratin remain
+undissolved.</p>
+
+<p><b>413. Contents of the Several Extracts.</b>—By the systematic
+treatment of muscular tissues in the manner just described, the
+nitrogenous bodies they contain are separated into five classes,
+<i>viz.</i>:</p>
+
+<p><i>Cold Water Extract.</i>—This contains serum albumin, serum
+globulin, muscle albumin, myosin, mucin and peptone.</p>
+
+<p><i>Ammonium Chlorid Extract.</i>—This solution contains the globulins
+and also in many cases some myosin and serum globulin.</p>
+
+<p><i>Hydrochloric Acid Extract.</i>—When the extractive matter removed
+by hydrochloric acid, thrown out by sodium carbonate and well washed
+with water, has a neutral reaction, it consists of syntonin, when acid,
+of an albuminate.</p>
+
+<p><i>Alkali Extract.</i>—The acid albumin of the animal tissue is found
+in the alkaline solution and may be thrown out by making the solution
+slightly acid.</p>
+
+<p><i>Insoluble Residue.</i>—The fifth class contains the insoluble
+nitrogenous bodies mentioned above.</p>
+
+<p><b>414. General Observations.</b>—Only a brief résumé of the methods
+of treating animal tissues for nitrogenous bases is given above, since
+a more elaborate discussion of these principles and methods would
+lead too far away from the main purpose of this manual. For practical
+purposes, the most important of these bodies are those soluble in water
+and the methods of treating these will be handled at some length.
+Unfortunately, the methods of determining the exact qualities of these
+bodies are not as satisfactory in case of animal as in vegetable
+nitrogenous bodies. The flesh bases, soluble in water, contain a much
+larger percentage of nitrogen than is found in true proteid bodies, and
+<span class="pagenum"><a id="Page_451"></a>[Pg 451]</span>
+therefore the multiplication of the weight of nitrogen found therein by
+6.25 does not give even a near approximation of the actual quantities
+of the nitrogenous bodies present in the sample.</p>
+
+<p>Some of the flesh bases contain more than twice as much nitrogen as
+is found in proteids, and in such cases 3.12, and not 6.25, would be
+the more correct factor to use in the computation. When possible,
+therefore, these bodies should be precipitated and weighed after
+drying, but this is not practicable in many instances. The sole
+resource of the chemist in such cases is to determine the nature of the
+body as nearly as possible by qualitive reactions, then to determine
+the total nitrogen therein and multiply its weight by the corresponding
+factor. The principal flesh bases have the following percentages of
+nitrogen and the approximate factors for calculating analytical data
+are also given:</p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb">Name of base.</th>
+      <th class="tdc bb">Formula.</th>
+      <th class="tdc bb">Per cent<br>&nbsp; nitrogen. &nbsp;</th>
+      <th class="tdc bb">Factor.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Glutin</td>
+      <td class="tdl_ws1 fs_105">C₁₃H₂₀N₄O₅</td>
+      <td class="tdc">17.95</td>
+      <td class="tdc">5.57</td>
+   </tr><tr>
+      <td class="tdl">Carnin</td>
+      <td class="tdl_ws1 fs_105">C₇H₈N₄O₂</td>
+      <td class="tdc">31.11</td>
+      <td class="tdc">3.21</td>
+   </tr><tr>
+      <td class="tdl">Kreatin</td>
+      <td class="tdl_ws1 fs_105">C₄H₁₉N₃O₂</td>
+      <td class="tdc">32.06</td>
+      <td class="tdc">3.12</td>
+   </tr><tr>
+      <td class="tdl">Kreatinin</td>
+      <td class="tdl_ws1 fs_105">C₄H₇N₃O₂</td>
+      <td class="tdc">37.17</td>
+      <td class="tdc">2.69</td>
+   </tr><tr>
+      <td class="tdl">Sarkin</td>
+      <td class="tdl_ws1 fs_105">C₅H₄N₄O</td>
+      <td class="tdc">41.18</td>
+      <td class="tdc">2.43</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>415. Composition of Meat Extracts.</b>—The meat extracts of
+commerce contain all the constituents of meat that are soluble in
+warm water. The parts which are soluble in warm water and not in cold
+are found in the cold aqueous solution as suspended or sedimentary
+matters. Among the nitrogenous bodies present are included albumin,
+albumose and peptone among the proteids, carnin, kreatin, kreatinin,
+sarkin and xanthin among the non-proteids, and inosinic and uric acids
+and urea among other nitrogenous bodies. Among the non-nitrogenous
+bodies are found lactic and butyric acids, inosit and glycogen. Among
+mineral bodies occurs the phosphates and chlorids of the common bases.
+In addition to these bodies, meat extracts may also contain gelatin
+and other decomposition products of proteid matter. Since meat extract
+is supposed to be prepared by the digestion of the meat free of bones
+and put in cold water or in warm water not above 75°, the presence of
+<span class="pagenum"><a id="Page_452"></a>[Pg 452]</span>
+gelatin would indicate a different method of preparation, <i>viz.</i>,
+either by boiling water or water heated above the boiling point under
+pressure. In a properly prepared extract, the percentage of gelatin is
+very small.</p>
+
+<p>Approximately one-tenth of the whole nitrogen present is in the form
+of albumoses and only a trace as peptones. By far the greater part of
+the nitrogen exists as flesh bases (kreatin, etc.). The composition of
+three meat extracts, numbers one and two solid and number three liquid,
+is given in the subjoined table.<a id="FNanchor_388" href="#Footnote_388" class="fnanchor">[388]</a></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc" colspan="3">&nbsp;</th>
+      <th class="tdc bb">No. 1.<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc bb">No. 2.<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc bb">No. 3.<br>&nbsp; Per cent. &nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl" colspan="3">Total nitrogen</td>
+      <td class="tdc">9.28</td>
+      <td class="tdc">9.14</td>
+      <td class="tdc">2.77</td>
+   </tr><tr>
+      <td class="tdl">Nitrogen</td>
+      <td class="tdl_wsp">as</td>
+      <td class="tdl_wsp">albumin</td>
+      <td class="tdc">trace</td>
+      <td class="tdc">0.08</td>
+      <td class="tdc">trace</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">albumose</td>
+      <td class="tdc">0.96</td>
+      <td class="tdc">1.21</td>
+      <td class="tdc">0.70</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">peptone</td>
+      <td class="tdc">trace</td>
+      <td class="tdc">trace</td>
+      <td class="tdc">none</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">flesh bases</td>
+      <td class="tdc">6.81</td>
+      <td class="tdc">5.97</td>
+      <td class="tdc">1.56</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">ammonia</td>
+      <td class="tdc">0.47</td>
+      <td class="tdc">0.41</td>
+      <td class="tdc">0.09</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">in</td>
+      <td class="tdl_wsp">compounds insoluble in</td>
+      <td class="tdc" colspan="3">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdl_ws1">sixty-six per cent alcohol</td>
+      <td class="tdc">0.21</td>
+      <td class="tdc">0.33</td>
+      <td class="tdc">0.25</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">other bodies</td>
+      <td class="tdc">0.83</td>
+      <td class="tdc">1.14</td>
+      <td class="tdc">0.17</td>
+   </tr>
+ </tbody>
+</table>
+
+<p id="P_417"><b>417. Analysis of Meat Extracts.</b>—The analysis of a meat extract
+should include the determination of the water, ash and total nitrogen.
+After multiplying the nitrogen which exists as proteids by 6.25 and
+adding together the percentages of all the ingredients, ash, water,
+etc., including ammonia, the sum is to be subtracted from 100 and the
+difference entered as non-nitrogenous organic matter. The nature of
+this conglomerate has already been explained.</p>
+
+<p><i>Water.</i>—It is advisable to determine the water in a partial
+vacuum (<b><a href="#P_20">20</a></b>) or in an atmosphere of hydrogen
+(<b><a href="#P_23">23-25</a></b>).</p>
+
+<p>The water may also be determined in solid extracts by placing about
+five grams of the material in a flat bottom tin foil dish about
+fifty-five millimeters in diameter and twenty millimeters deep. The
+material is dissolved in enough warm water to fill the dish a little
+over one-half and the liquid is then absorbed by adding a weighed
+quantity of fibrous asbestos or of dry fragments of pumice stone.
+The asbestos is to be preferred because of the fact that it may be
+subsequently cut into small bits for the determination of the gelatin.
+<span class="pagenum"><a id="Page_453"></a>[Pg 453]</span>
+The dish thus prepared is dried to constant weight in a steam-bath
+or vacuum oven. The weight of the dish and of the added absorbent,
+together with that of the material employed and of the dried dish and
+its contents, give the data for calculating the percentage of water.
+The contents of the dish are used as described further on for the
+determination of gelatin. In liquid extracts the water is determined in
+an entirely analogous manner, using about twenty grams of the material
+and omitting the solution in water.</p>
+
+<p>In solid extracts, the part insoluble in cold water is determined
+separately.</p>
+
+<p><i>Ash.</i>—The ash is determined by ignition at the lowest possible
+temperature, best in a muffle (<b><a href="#P_28">28-32</a></b>). The ash should be
+examined qualitively. Where a quantitive analysis is desired, larger
+quantities of the extract are incinerated and the constituents of the
+ash determined in the usual way.<a id="FNanchor_389" href="#Footnote_389" class="fnanchor">[389]</a></p>
+
+<p><i>Total Nitrogen.</i>—Since nitrates are not present unless added
+in the manufacture, the total nitrogen is best determined by moist
+combustion.<a id="FNanchor_390" href="#Footnote_390" class="fnanchor">[390]</a></p>
+
+<p><i>Nitric Nitrogen.</i>—The extract should be tested for nitrates and
+if present they are determined in the manner already described.<a id="FNanchor_391" href="#Footnote_391" class="fnanchor">[391]</a></p>
+
+<p><i>Ammoniacal Nitrogen.</i>—When ammonia is present it is determined
+by distillation with magnesia.<a id="FNanchor_392" href="#Footnote_392" class="fnanchor">[392]</a></p>
+
+<p>Since boiling with magnesia may cause the distillation of more
+ammonia than is present as ammonium salts, the plus being due to the
+decomposition of some other nitrogenous compounds, Stutzer replaces the
+magnesia with barium carbonate.<a id="FNanchor_393" href="#Footnote_393" class="fnanchor">[393]</a></p>
+
+<p><i>Proteid Nitrogen Insoluble in Sixty-Two Per Cent Alcohol.</i>—The
+aqueous solution is treated with strong alcohol until the mixture
+contains about sixty-two per cent of the reagent. The precipitate
+produced is separated by filtration, washed with sixty-two per cent
+alcohol and the nitrogen therein determined.</p>
+
+<p><i>Albumose Nitrogen.</i>—This is secured by saturating the aqueous
+solution with zinc or ammonium sulfate. The separated albumoses are
+skimmed from the surface, thrown in a filter, washed with a saturated
+<span class="pagenum"><a id="Page_454"></a>[Pg 454]</span>
+solution of zinc sulfate and the nitrogen determined therein by moist
+combustion. In the filtrate from the above separation, peptone is
+detected qualitively by adding a few drops of dilute solution of copper
+sulfate (biuret reaction).</p>
+
+<p><i>Kreatin, Kreatinin and Other Flesh Bases.</i>—The clear, aqueous
+solution of the extract is acidified with sulfuric, mixed with a
+solution of sodium phosphotungstate and allowed to stand for about
+six days. The precipitate is collected, washed with a solution of
+the precipitant, and the nitrogen therein determined. The nitrogen
+found, less that due to ammonia, represents the total nitrogenous
+matter precipitated by the phosphotungstic acid. From this quantity
+is deducted the nitrogen in the proteids, precipitated by sixty-two
+per cent alcohol and by ammonium or zinc sulfate, and the remainder
+represents the nitrogen in flesh bases.</p>
+
+<p>The nitrogen thrown out by the phosphotungstic acid is deducted from
+the total nitrogen, and the remainder represents the nitrogenous bodies
+not precipitable by the reagent named.</p>
+
+<p>This method of separating the nitrogenous matters in meat extracts is
+based on the observation that these bodies contain at most only a small
+quantity of peptones, so small as to be safely negligible.<a id="FNanchor_394" href="#Footnote_394" class="fnanchor">[394]</a></p>
+
+<p><i>Quantities used for Analysis.</i>—In conducting the separations
+above noted, it will be found convenient to use in each case about
+five grams of the solid or twenty of the liquid extract. In the
+nitrogen determinations, the weight of the sample should be inversely
+proportional to its content of nitrogen.</p>
+
+<p><b>417. Preparation of the Phosphotungstic Reagent.</b>—The
+phosphotungstic reagent is conveniently prepared as follows:</p>
+
+<p>Dissolve 120 grams of sodium phosphate and 200 of sodium tungstate in
+one liter of water and add to the solution 100 cubic centimeters of
+strong sulfuric acid. When the reagent is prepared for general purposes
+it is customary to acidify with nitric, but in the present instance,
+inasmuch as the precipitate is used for the determination of nitrogen,
+it is evident that sulfuric should be substituted for nitric acid. In
+<span class="pagenum"><a id="Page_455"></a>[Pg 455]</span>
+all cases the analyst must be assured of the strong acidity of the
+reagent, and in addition to this the solutions of proteid matter to
+which the reagent is added must first be made strongly acid with
+sulfuric.</p>
+
+<p><b>418. Zinc Sulfate as Reagent for Separating Albumoses from
+Peptones.</b>—When the albumoses are separated from the peptones, by
+precipitation with ammonium sulfate, there may be danger of some of
+this reagent adhering to the albumose, and in this way the quantity of
+nitrogen obtained on analysis may be increased. To avoid an accident of
+this kind Bömer replaces the ammonium by zinc sulfate.<a id="FNanchor_395" href="#Footnote_395" class="fnanchor">[395]</a></p>
+
+<p>Since the precipitation of the albumoses by saturated saline solutions
+depends on their hydrolytic power, the substitution of another salt
+for ammonium sulfate capable of strongly attracting water, may be made
+if that salt does not possess any objectionable property. Crystallized
+zinc sulfate will dissolve in less than its own weight of cold water
+and is therefore well suited for the purpose in view.</p>
+
+<p>In the case of a meat extract, the precipitation is accomplished as
+follows: Fifty cubic centimeters of the extract, freed from all solid
+matter by filtration and containing about two grams of the soluble
+proteids, are saturated in the cold with finely powdered zinc sulfate.
+The separated albumoses collect on the surface and are skimmed off,
+poured on a filter and washed with cold saturated zinc sulfate
+solution. The filter and its contents are used for the determination of
+nitrogen by moist combustion.<a id="FNanchor_396" href="#Footnote_396" class="fnanchor">[396]</a></p>
+
+<p>The filtrate from the precipitated albumoses gives no biuret reaction,
+and, therefore, as in the use of ammonium sulfate, is free of albumin.</p>
+
+<p>The biuret reaction is applied to the zinc sulfate filtrate as follows:
+The filtrate is greatly diluted with water and freed of zinc by means
+of a saturated solution of sodium carbonate. The filtrate free of zinc
+is evaporated on the steam-bath, made strongly alkaline with sodium
+hydroxid and treated with a few drops of a two per cent copper sulfate
+solution, added successively.</p>
+
+<p>Another advantage possessed by the zinc sulfate is found in the fact
+<span class="pagenum"><a id="Page_456"></a>[Pg 456]</span>
+that in the filtrate from the separated albumoses the peptones and
+other flesh bases can be thrown out by phosphotungstic acid. Before the
+application of the reagent, the filtrate should be made strongly acid
+by adding about an equal volume of dilute sulfuric acid (one part of
+acid to four of water.)</p>
+
+<p>The nitrogen in the precipitate thus obtained is determined by moist
+combustion in the manner already suggested.</p>
+
+<p>If the proteid matters contain salts of ammonium it is probable
+that a difficultly soluble double sulfate of zinc and ammonium,
+<b>(NH₄)₂SO₄.ZnSO₄.6H₂O</b>, will be found in the precipitate. Ammonium salts,
+if present, should therefore be removed by distillation with magnesia.
+It is better, however, to throw down the ammonia with the first zinc
+precipitate, distil this with magnesia and determine the amount of
+nitrogen derived from the ammonia compounds. In a second sample, the
+total nitrogen is determined by moist combustion and the difference
+between the two results gives that due to albumoses.</p>
+
+<p><b>419. Examination for Muscular Tissue.</b>—Some samples of meat
+extracts contain small quantities of finely ground muscular tissue. For
+detecting this the extract is treated with cold water and the insoluble
+residue examined with a microscope. If muscular tissue be found, about
+eight grams of the extract or twenty-five of the fluid preparation, are
+treated with cold water, the insoluble matter collected upon a filter,
+washed with cold water, and the nitrogen determined in the residue. The
+percentage of nitrogen multiplied by 6.25 gives the quantity of muscle
+fiber proteids present. The filtrate from the above determination
+is acidified with acetic, boiled, any precipitate which is formed
+collected and the nitrogen therein determined. The nitrogen obtained
+multiplied by 6.25 gives the quantity of coagulable albumin present.
+An aliquot portion of the filtrate is used for the determination of
+nitrogen and the percentage therein found, deducted from the total
+nitrogen of the sample, gives a remainder which may be used as a
+representative of the whole of the nitrogen present in the form of
+albumin and muscular tissue.</p>
+
+<p><b>420. Estimation of Gelatin.</b>—The tin foil dish and its contents
+used for the determination of water, as above described, are cut into
+<span class="pagenum"><a id="Page_457"></a>[Pg 457]</span>
+small pieces, placed in a beaker and extracted four times with
+absolute alcohol. After the removal of the alcohol, the residue is
+extracted with ice water containing ten per cent of alcohol, in
+which a small piece of ice is kept to avoid a rise of temperature.
+The beaker should be shaken during the extraction, which should last
+for about two minutes. Where large numbers of samples are treated
+at once, any convenient form of shaking machine may be employed. At
+least two extractions with ice water must be made. The residue is then
+collected upon a filter and washed with ice water until the washings
+are completely colorless. The residue on the filter is replaced in
+the beaker, boiled with water, well washed on the filter with boiling
+water, the filtrate and washings concentrated and the nitrogen therein
+determined.</p>
+
+<p>The principle of this determination is based on the fact that gelatin
+is almost completely insoluble in ice water while serum peptones and
+albumin peptones are almost completely soluble in that reagent. On
+the other hand, the flesh bases and the proteids present are almost
+completely removed by the preliminary treatment with alcohol and ice
+water or are left undissolved by the hot water. The solution in boiling
+water, therefore, contains practically nothing but gelatin.<a id="FNanchor_397" href="#Footnote_397" class="fnanchor">[397]</a></p>
+
+<p>In a later article, Stutzer modifies the method given above as
+follows:<a id="FNanchor_398" href="#Footnote_398" class="fnanchor">[398]</a></p>
+
+<p>Of dry and moist extracts from five to seven grams and of liquid
+extracts from twenty to twenty-five grams are used for the
+determination and placed in tin foil dishes, as described above. In
+case of solid extracts, a sufficient quantity of warm water is added to
+completely dissolve them, the solution being facilitated by stirring.
+In case the solution is too thin it should be concentrated before going
+further. It is treated with a sufficient amount of dust-free ignited
+sand to completely absorb it, and the dish and its contents are then
+dried to a constant weight. The dried contents of the dish are rubbed
+up in a mortar, the dish cut into fine bits, and all placed in a
+beaker. The solid syrphete<a id="FNanchor_399" href="#Footnote_399" class="fnanchor">[399]</a>
+is extracted four times with 100 cubic centimeters of absolute alcohol,
+the alcohol in each case being poured through an asbestos filter for
+<span class="pagenum"><a id="Page_458"></a>[Pg 458]</span>
+the purpose of collecting any matters suspended therein. In a large
+flask are placed 100 grams of alcohol, 300 grams of ice and 600 grams
+of cold water, and the flask is placed in a large vessel and packed
+with finely divided ice. Four beakers marked <i>b, c, d, e</i> are
+also placed in ice and the beaker containing the syrphete, left after
+extraction with absolute alcohol as above mentioned, is marked <i>a</i>
+and also placed in pounded ice. The extraction with cold alcoholic
+water proceeds as follows:</p>
+
+<p>In beaker <i>a</i> are poured 100 cubic centimeters of the mixture in
+the large flask, its contents are stirred for two minutes and then the
+liquid portion poured off into beaker <i>b</i> to which, at the same
+time, a piece of ice is added. In beaker <i>a</i> are poured again 100
+cubic centimeters from the large flask, treated as above described,
+and the liquid extract poured into beaker <i>c</i>. In like manner the
+extraction in beaker <i>a</i> is continued until each of the beakers
+has received its portion of the extract. By this time the liquid
+over the sand in beaker <i>a</i> should be completely colorless. The
+filtration of the liquid extract is accomplished as follows:</p>
+
+<p>In a funnel of about seven centimeters diameter is placed a perforated
+porcelain plate about four centimeters in diameter which is covered
+with asbestos felt with long fiber. Three filters are prepared in this
+way. On the first filter are poured the contents of beaker <i>b</i>.
+After the liquid has passed through, the sand and other residue in
+beaker <i>a</i> are transferred to the filter and the beaker and
+residue washed with the alcoholic ice water from the large flask. The
+filtration should be accomplished under pressure. On the second filter
+are poured the contents of beaker <i>c</i>. On the third filter the
+contents of beakers <i>d</i> and <i>e</i>. The washing with alcoholic
+ice water from the large flask is continued in each instance until the
+filtrate is colorless. At the same time the asbestos filter, which was
+used in the first instance for filtering the absolute alcohol extract,
+is washed with the alcoholic ice water mixture from the large flask. At
+the end the sand remaining in beaker a together with all the asbestos
+filters are brought together into a porcelain dish, boiled two or
+three times with water, the aqueous solution filtered and the filtrate
+concentrated and used for the estimation of the nitrogen. The quantity
+<span class="pagenum"><a id="Page_459"></a>[Pg 459]</span>
+of nitrogen found multiplied by 6.25 represents the proteid matter in
+the gelatin of the sample.</p>
+
+<p>The object of the multiple filters, described above, is to accelerate
+the process, and they are required because the gelatin quickly occludes
+the filter pores. For this reason the asbestos filters are found
+to operate better than those made of paper. It should be mentioned
+that the residue of the peptones insoluble in alcohol may contain,
+in addition to gelatin, also small quantities of albumoses. From the
+quantity of albumose nitrogen found, it is understood that the nitrogen
+in the form of coagulable albumin, determined as described in the first
+process mentioned above, is to be deducted, since these coagulable
+albumins are insoluble in alcohol.</p>
+
+<p><b>421. Estimation of Nitrogen in the Flesh Bases Soluble in
+Alcohol.</b>—About five grams of the dry extract, ten grams of the
+extract containing water or twenty-five grams of the liquid extract
+are placed in a beaker and enough water added in each case to make
+about twenty-five cubic centimeters in all. Usually no water need be
+added to the liquid extracts. Very thin peptone solutions should be
+evaporated until the content of water is reduced to seventy-five per
+cent. The solution, prepared as above indicated, is treated slowly
+with constant stirring with 250 cubic centimeters of absolute alcohol,
+the stirring continued for some minutes and the vessel set aside for
+twelve hours, at the end of which time the precipitate is separated by
+filtration and washed repeatedly with strong alcohol. Leucin, tyrosin
+and a part of the flesh bases are dissolved by alcohol. The alcohol is
+removed by distillation and the residue dissolved in water. Any flocky
+residue which remains on solution with water is removed by filtration,
+the nitrogen determined therein and the quantity thereof added to the
+albumose nitrogen found, as hereafter described.</p>
+
+<p>The volume of the aqueous solution is completed with water to half a
+liter. One hundred cubic centimeters of this solution are used for the
+determination of total nitrogen, and another 100 cubic centimeters for
+the determination of ammoniacal nitrogen by distillation with barium
+<span class="pagenum"><a id="Page_460"></a>[Pg 460]</span>
+carbonate. A part of the ammonia may have escaped during the
+preliminary distillation of the alcohol and therefore the amount found
+may not represent the whole amount originally present. The use of the
+above determination is principally to ascertain the correction to be
+made in the amount of total nitrogen found in the first 100 cubic
+centimeters of the solution.</p>
+
+<p><b>422. Treatment of the Residue Insoluble in Alcohol.</b>—The
+residue insoluble in alcohol is washed from the filter into the beaker
+in which the first solution was made. The aqueous mixture is warmed
+on a water-bath until the alcohol adhering to the precipitate is
+completely evaporated, when the contents of the beaker are poured upon
+a filter free of nitrogen. A small part of the albumose, by reason of
+the treatment with alcohol, tends to remain undissolved, and it is
+advisable to collect this albumose upon a filter, wash it well with hot
+water and estimate the nitrogen therein. The quantity of nitrogen thus
+found is to be added to the albumose nitrogen determined as described
+later on.</p>
+
+<p>The total filtrate obtained from the last filtration is made up to
+a volume of half a liter, of which fifty cubic centimeters are used
+for the determination of total nitrogen, fifty cubic centimeters for
+the determination of gelatin, albumose and peptone, and 100 cubic
+centimeters for the residual peptones. The albumose, together with the
+gelatin and peptones carried down with it, is precipitated with zinc or
+ammonium sulfate solution, and its per cent calculated from the amount
+of nitrogen found in the precipitate. The true peptone is determined by
+subtracting the quantity of nitrogen determined as albumose from the
+total nitrogen in solution.</p>
+
+<p>The rest of the liquid, <i>viz.</i>, 300 cubic centimeters, is
+evaporated to a small volume and tested qualitively for true peptones
+as follows:</p>
+
+<p>To separate the albumose and gelatin a concentrated liquor is treated
+with an excess of finely divided ammonium sulfate so that a part of
+the salt remains undissolved. The separated albumose, gelatin and
+undissolved ammonium salts are collected on a filter, the filtrate
+mixed with a few drops of dilute copper sulfate solution and a
+<span class="pagenum"><a id="Page_461"></a>[Pg 461]</span>
+considerable quantity of concentrated soda or potash lye added. Care
+should be taken that the quantity of copper is not too great, otherwise
+the peculiar red coloration will be obscured by the blue color of the
+copper solution.</p>
+
+<p><b>423. Pancreas Peptone.</b>—The filtrate obtained as described
+above, by treating the portion of the material insoluble in alcohol
+with warm water, contains in addition to the albumose and gelatin the
+whole of the pancreas peptone which may be present. To separate this
+peptone, 100 cubic centimeters of the aqueous solution are evaporated
+in a porcelain dish until the volume does not exceed ten cubic
+centimeters. When cool, at least 100 cubic centimeters of a saturated
+cooled solution of ammonium sulfate solution are added, the mixture
+thoroughly stirred, the precipitate collected upon a filter and washed
+with a cold saturated solution of ammonium sulfate. The contents of
+the filter are dissolved in boiling water, the filter thoroughly
+washed and the filtrate and washings evaporated in a porcelain dish
+with the addition of barium carbonate until, on the addition of new
+quantities of barium carbonate, no further trace of ammonia can be
+discovered. The residue is extracted with water, the barium sulfate and
+carbonate present separated by filtration, well washed and the nitrogen
+determined in the evaporated filtrate and washings in the usual way and
+multiplied by 6.25 to determine the quantity of pancreas peptone.</p>
+
+<p><b>424. Albumose Peptone.</b>—A part of the albumose peptone which may
+be present is determined in conjunction with the other bodies mentioned
+above. The chief quantity is found in the solution of the residue
+insoluble in alcohol in the following manner:</p>
+
+<p>Fifty cubic centimeters of the solution of this residue in hot water
+are mixed with an equal volume of dilute sulfuric acid, one volume
+of acid to three of water, in the cold, and a solution of sodium
+phosphotungstate added until it produces no further precipitate. The
+precipitate is washed with dilute sulfuric acid and the nitrogen
+determined therein. The nitrogen thus found is derived from the
+albumose, pancreas peptone and gelatin. The quantity of nitrogen in the
+pancreas peptone and gelatin, as above described, is subtracted from
+<span class="pagenum"><a id="Page_462"></a>[Pg 462]</span>
+the total quantity found in the phosphotungstic acid precipitated, and
+the remainder represents the nitrogen due to the albumose.</p>
+
+<p><b>425. Nitrogen in the Form of Flesh Bases Insoluble in
+Alcohol.</b>—This is determined by subtracting the quantity of
+nitrogen, determined by the phosphotungstic acid method already
+described, from the total quantity of nitrogen found in the precipitate
+insoluble in alcohol and soluble in water.</p>
+
+<h3>AUTHORITIES CITED IN PART FIFTH.</h3>
+<div class="footnotes">
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_337" href="#FNanchor_337" class="label">[337]</a>
+Watts’ Dictionary of Chemistry, new edition, Vol. 4, p. 327.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_338" href="#FNanchor_338" class="label">[338]</a>
+Vid. op. cit. supra, p. 330.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_339" href="#FNanchor_339" class="label">[339]</a>
+Barbieri, Journal für praktische Chemie, neue Folge Band 18, S. 114.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_340" href="#FNanchor_340" class="label">[340]</a>
+Vid. op. cit. 1, p. 339.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_341" href="#FNanchor_341" class="label">[341]</a>
+Bulletin No. 49, Kansas Experiment Station, May, 1895.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_342" href="#FNanchor_342" class="label">[342]</a>
+This work, Vol. 2, p. 208.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_343" href="#FNanchor_343" class="label">[343]</a>
+Vid. op. cit. supra, Vol. 1, p. 570.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_344" href="#FNanchor_344" class="label">[344]</a>
+Wiley, American Chemical Journal, Vol. 6, No. 5, p. 289.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_345" href="#FNanchor_345" class="label">[345]</a>
+Obermayer, Chemiker-Zeitung Repertorium, Oct. 1889, S. 269.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_346" href="#FNanchor_346" class="label">[346]</a>
+ Hoppe-Seyler, Handbuch der physiologisch- und
+pathologisch-chemischen Analyse, S. 269.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_347" href="#FNanchor_347" class="label">[347]</a>
+Wiley, American Chemical Journal, Vol. 6, p. 289.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_348" href="#FNanchor_348" class="label">[348]</a>
+Dragendorff’s Plant Analysis, p. 55.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_349" href="#FNanchor_349" class="label">[349]</a>
+This work, Vol. 2, pp. 192 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_350" href="#FNanchor_350" class="label">[350]</a>
+Chemiker-Zeitung, Band 20, S. 151.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_351" href="#FNanchor_351" class="label">[351]</a>
+This work, Vol. 2, p. 207.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_352" href="#FNanchor_352" class="label">[352]</a>
+Landwirtschaftlichen Versuchs-Stationen, Band 17, S. 321:
+Zeitschrift für analytische Chemie, Band 14, S. 380.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_353" href="#FNanchor_353" class="label">[353]</a>
+Vid. op. cit. 12, p. 245.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_354" href="#FNanchor_354" class="label">[354]</a>
+Landwirtschaftlichen Versuchs-Stationen, Band 16, S. 61.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_355" href="#FNanchor_355" class="label">[355]</a>
+Berichte der deutschen chemischen Gesellschaft, Band 10,
+Ss. 85, 199; Band 16, S. 312: Chemiker-Zeitung, Band 20, S. 145.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_356" href="#FNanchor_356" class="label">[356]</a>
+Zeitschrift für analytische Chemie, Band 22, S. 325.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_357" href="#FNanchor_357" class="label">[357]</a>
+Richardson and Crampton, Berichte der deutschen
+chemischen Gesellschaft, Band 19, S. 1180.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_358" href="#FNanchor_358" class="label">[358]</a>
+Maxwell, American Chemical Journal, Vol. 13, p. 470.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_359" href="#FNanchor_359" class="label">[359]</a>
+Vid. op. cit. supra, Vol. 15, p. 185.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_360" href="#FNanchor_360" class="label">[360]</a>
+Vid. op. cit. supra, Vol. 13, p. 13: Schulze, Zeitschrift
+physiologische Chemie, Band 14, S. 491.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_361" href="#FNanchor_361" class="label">[361]</a>
+This work, Vol. I, p. 411.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_362" href="#FNanchor_362" class="label">[362]</a>
+Vid. op. cit., 22, Vol. 13, p. 15.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_363" href="#FNanchor_363" class="label">[363]</a>
+Vid. op. cit. supra, Vol. 15, p. 188.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_364" href="#FNanchor_364" class="label">[364]</a>
+Hoppe-Seyler, Handbuch der physiologisch- und
+pathologisch-chemischen Analyse, S. 169.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_463"></a>[Pg 463]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_365" href="#FNanchor_365" class="label">[365]</a>
+This work, Vol. 2, p. 225.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_366" href="#FNanchor_366" class="label">[366]</a>
+Bulletin No. 45, Division of Chemistry, U. S. Department of Agriculture, p. 51.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_367" href="#FNanchor_367" class="label">[367]</a>
+Osborne and Voorhees, American Chemical Journal, Vol. 15, p. 470.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_368" href="#FNanchor_368" class="label">[368]</a>
+Vid. op. cit. supra, Vol. 13, p. 385.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_369" href="#FNanchor_369" class="label">[369]</a>
+Vid. op. cit. supra, p. 412.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_370" href="#FNanchor_370" class="label">[370]</a>
+Vid. op. cit. supra, Vol. 15, p. 402.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_371" href="#FNanchor_371" class="label">[371]</a>
+Vid. op. cit. supra, p. 404.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_372" href="#FNanchor_372" class="label">[372]</a>
+Zeitschrift für analytische Chemie, Band 34, S. 562.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_373" href="#FNanchor_373" class="label">[373]</a>
+Vid. op. cit. 34, p. 404.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_374" href="#FNanchor_374" class="label">[374]</a>
+Vid. op. cit. 3, p. 455.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_375" href="#FNanchor_375" class="label">[375]</a>
+Osborne and Voorhees, vid. op. cit. 34, p. 409.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_376" href="#FNanchor_376" class="label">[376]</a>
+Vid. op. cit. supra, Vol. 13, p. 464.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_377" href="#FNanchor_377" class="label">[377]</a>
+Chittenden and Osborne, op. cit. supra, Vol. 14, p. 32.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_378" href="#FNanchor_378" class="label">[378]</a>
+Vid. op. cit. supra, p. 41.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_379" href="#FNanchor_379" class="label">[379]</a>
+Vid. op. cit. supra, p. 639.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_380" href="#FNanchor_380" class="label">[380]</a>
+Vid. op. cit. supra, Vol. 13, p. 399.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_381" href="#FNanchor_381" class="label">[381]</a>
+Vid. op. cit. supra, pp. 395, 400, 401.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_382" href="#FNanchor_382" class="label">[382]</a>
+Vid. op. cit. supra, p. 409.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_383" href="#FNanchor_383" class="label">[383]</a>
+This work, Vol. 1, p. 319.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_384" href="#FNanchor_384" class="label">[384]</a>
+This work, Vol. 2, pp. 169 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_385" href="#FNanchor_385" class="label">[385]</a>
+Vid. op. cit. 47, p. 420.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_386" href="#FNanchor_386" class="label">[386]</a>
+Osborne, vid. op. cit. 44, p. 410.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_387" href="#FNanchor_387" class="label">[387]</a>
+Hoppe-Seyler, Handbuch der physiologisch- und
+pathologisch-chemischen Analyse.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_388" href="#FNanchor_388" class="label">[388]</a>
+König und Bömer, Zeitschrift für analytische Chemie, Band 34, S. 560.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_389" href="#FNanchor_389" class="label">[389]</a>
+This work, Vol. 2, pp. 297, 298.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_390" href="#FNanchor_390" class="label">[390]</a>
+Vid. op. cit. supra, p. 184.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_391" href="#FNanchor_391" class="label">[391]</a>
+Vid. op. cit. supra, p. 206.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_392" href="#FNanchor_392" class="label">[392]</a>
+This work, Vol. I, p. 450; Vol. 2, p. 226.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_393" href="#FNanchor_393" class="label">[393]</a>
+Zeitschrift für analytische Chemie, Band 34, S. 377.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_394" href="#FNanchor_394" class="label">[394]</a>
+König und Bömer, vid. op. cit. supra, S. 560.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_395" href="#FNanchor_395" class="label">[395]</a>
+Vid. op. cit. supra, S. 562.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_396" href="#FNanchor_396" class="label">[396]</a>
+Vid. op. cit. 53, p. 184.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_397" href="#FNanchor_397" class="label">[397]</a>
+Vid. op. cit. 57, S. 374.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_398" href="#FNanchor_398" class="label">[398]</a>
+Vid. op. cit. supra, S. 568.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_399" href="#FNanchor_399" class="label">[399]</a>
+From συρφετος.</p>
+</div>
+</div>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum"><a id="Page_464"></a>[Pg 464]</span></p>
+<h2 class="nobreak">PART SIXTH.<br>
+<span class="h_subtitle">DAIRY PRODUCTS.</span></h2>
+</div>
+
+<p><b>426. Introductory.</b>—The importance of dairy products has led to
+the publication of a vast amount of literature relating thereto, and
+it seems almost a hopeless task to present even a typical abstract of
+the various analytical processes which have been proposed and used in
+their study. The general principles which have been developed in the
+preceding parts of this volume are applicable to the study of dairy
+products, and the analyst who is guided by them can intelligently
+examine the bodies specially considered in the present part. There
+have been developed, however, many valuable processes for the special
+examination of dairy products, which are of such a nature that they
+could not be properly discussed in the preceding pages. In the present
+part an effort will be made to present in a typical form the most
+important of these processes and to state the general principles on
+which they are based. This subject is naturally subdivided into three
+parts, <i>viz.</i>, milk, butter and cheese. The milk sugar industry is
+not of sufficient importance to receive a special classification.</p>
+
+<h3>MILK.</h3>
+
+<p><b>427. Composition of Milk.</b>—The composition of milk not only
+varies with the genus and species of the mammal from which it is
+derived, but also depends in a marked degree on idiosyncrasy.<a id="FNanchor_400" href="#Footnote_400" class="fnanchor">[400]</a></p>
+
+<p>Milk is a mixture containing water, proteids, fat, carbohydrates,
+organic and inorganic acids and mineral salts. There have also been
+observed in milk in minute quantities ammonia, urea, hypoxanthin,
+chyme, chyle, biliverdin, cholesterin, mucin, lecithin, kreatin, leucin
+and tyrosin. In the fermentation which milk undergoes in incipient
+decomposition there is sometimes developed from the proteid matter, as
+pointed out by Vaughn, a ptomaine, tyrotoxicon, which is a virulent
+poison.<a id="FNanchor_401" href="#Footnote_401" class="fnanchor">[401]</a>
+The presence of these last named bodies is of interest chiefly to the
+physiologist and pathologist and can receive no further attention here.
+<span class="pagenum"><a id="Page_465"></a>[Pg 465]</span></p>
+
+<p>From a nutritive point of view, the important components of milk are
+the fats, proteids and sugar, but especially in the nourishment of the
+young the value of lime and phosphoric acid must be remembered. The
+mean composition of the most important milks, as determined by recent
+analyses, is given below:</p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc">&nbsp;</th>
+      <th class="tdc bb">Water.<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc bb">Sugar.<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc bb">Proteids.<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc bb">Fat.<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc bb">Ash.<br>&nbsp; Per cent. &nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Cow</td>
+      <td class="tdc">86.90</td>
+      <td class="tdc">4.80</td>
+      <td class="tdc">3.60</td>
+      <td class="tdc">4.00</td>
+      <td class="tdc">0.70</td>
+   </tr><tr>
+      <td class="tdl">Human</td>
+      <td class="tdc">88.75</td>
+      <td class="tdc">6.00</td>
+      <td class="tdc">1.50</td>
+      <td class="tdc">3.45</td>
+      <td class="tdc">0.30</td>
+   </tr><tr>
+      <td class="tdl">Goat</td>
+      <td class="tdc">85.70</td>
+      <td class="tdc">4.45</td>
+      <td class="tdc">4.30</td>
+      <td class="tdc">4.75</td>
+      <td class="tdc">0.80</td>
+   </tr><tr>
+      <td class="tdl">Ass</td>
+      <td class="tdc">89.50</td>
+      <td class="tdc">6.25</td>
+      <td class="tdc">2.00</td>
+      <td class="tdc">1.75</td>
+      <td class="tdc">0.50</td>
+   </tr><tr>
+      <td class="tdl">Mare</td>
+      <td class="tdc">90.75</td>
+      <td class="tdc">5.70</td>
+      <td class="tdc">2.00</td>
+      <td class="tdc">1.20</td>
+      <td class="tdc">0.35</td>
+   </tr><tr>
+      <td class="tdl">Sheep</td>
+      <td class="tdc">80.80</td>
+      <td class="tdc">4.90</td>
+      <td class="tdc">6.55</td>
+      <td class="tdc">6.85</td>
+      <td class="tdc">0.90</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The mean composition of milk, as given by Watts and König, is given in
+the following tables:</p>
+
+<table class="spb1">
+   <thead><tr class="smcap fs_120">
+      <th class="tdc">&nbsp;</th>
+      <th class="tdc" colspan="6">Watts.</th>
+   </tr><tr>
+      <th class="tdc">&nbsp;</th>
+      <th class="tdc_bott bb">&nbsp; Water. &nbsp;</th>
+      <th class="tdc_bott bb">&nbsp; Solids. &nbsp;</th>
+      <th class="tdc_bott bb">&nbsp; Proteids. &nbsp;</th>
+      <th class="tdc_bott bb">&nbsp; Fats. &nbsp;</th>
+      <th class="tdc_bott bb">&nbsp; Sugar. &nbsp;</th>
+      <th class="tdc bb">&nbsp; Mineral &nbsp;<br>Salts.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Woman</td>
+      <td class="tdc">87.65</td>
+      <td class="tdc">12.35</td>
+      <td class="tdc">3.07</td>
+      <td class="tdc">3.91</td>
+      <td class="tdc">5.01</td>
+      <td class="tdc">0.17</td>
+   </tr><tr>
+      <td class="tdl">Ass</td>
+      <td class="tdc">90.70</td>
+      <td class="tdc">&#8199;9.30</td>
+      <td class="tdc">1.70</td>
+      <td class="tdc">1.55</td>
+      <td class="tdc">5.80</td>
+      <td class="tdc">0.50</td>
+   </tr><tr>
+      <td class="tdl">Cow</td>
+      <td class="tdc">86.56</td>
+      <td class="tdc">13.44</td>
+      <td class="tdc">4.08</td>
+      <td class="tdc">4.03</td>
+      <td class="tdc">4.60</td>
+      <td class="tdc">0.73</td>
+   </tr><tr>
+      <td class="tdl">Goat</td>
+      <td class="tdc">86.76</td>
+      <td class="tdc">13.24</td>
+      <td class="tdc">4.23</td>
+      <td class="tdc">4.48</td>
+      <td class="tdc">3.91</td>
+      <td class="tdc">0.62</td>
+   </tr><tr>
+      <td class="tdl">Sheep</td>
+      <td class="tdc">83.31</td>
+      <td class="tdc">16.69</td>
+      <td class="tdc">5.73</td>
+      <td class="tdc">6.05</td>
+      <td class="tdc">3.96</td>
+      <td class="tdc">0.68</td>
+   </tr><tr>
+      <td class="tdl">Mare</td>
+      <td class="tdc">82.84</td>
+      <td class="tdc">17.16</td>
+      <td class="tdc">1.64</td>
+      <td class="tdc">6.87</td>
+      <td class="tdc" colspan="2">8.65</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1">
+   <thead><tr class="smcap fs_120">
+      <th class="tdc" colspan="6">König.</th>
+   </tr><tr>
+      <th class="tdc">&nbsp;</th>
+      <th class="tdc_bott bb">&nbsp; Water. &nbsp;</th>
+      <th class="tdc_bott bb">&nbsp; Fat. &nbsp;</th>
+      <th class="tdc bb">&nbsp; Casein and &nbsp;<br>albumin.</th>
+      <th class="tdc_bott bb">Milk<br>&nbsp; Sugar. &nbsp;</th>
+      <th class="tdc bb">&nbsp; Ash. &nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Woman</td>
+      <td class="tdc">87.41</td>
+      <td class="tdc">3.78</td>
+      <td class="tdc">2.29</td>
+      <td class="tdc">6.21</td>
+      <td class="tdc">0.31</td>
+   </tr><tr>
+      <td class="tdl">Mare</td>
+      <td class="tdc">90.78</td>
+      <td class="tdc">1.21</td>
+      <td class="tdc">1.99</td>
+      <td class="tdc">5.67</td>
+      <td class="tdc">0.35</td>
+   </tr><tr>
+      <td class="tdl">Ass</td>
+      <td class="tdc">89.64</td>
+      <td class="tdc">1.63</td>
+      <td class="tdc">2.22</td>
+      <td class="tdc">5.99</td>
+      <td class="tdc">0.51</td>
+   </tr><tr>
+      <td class="tdl">Cow</td>
+      <td class="tdc">87.17</td>
+      <td class="tdc">3.69</td>
+      <td class="tdc">3.55</td>
+      <td class="tdc">4.88</td>
+      <td class="tdc">0.71</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The average composition of 120,540 samples of cow milk, as determined
+by analysis, extending over a period of eleven years, was found by
+Vieth to be as follows:<a id="FNanchor_402" href="#Footnote_402" class="fnanchor">[402]</a></p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdr">Per cent.</td>
+   </tr><tr>
+      <td class="tdl">Total solids</td>
+      <td class="tdc">12.9</td>
+   </tr><tr>
+      <td class="tdl">Solids not fat&emsp;&nbsp;</td>
+      <td class="tdc">&#8199;8.8</td>
+   </tr><tr>
+      <td class="tdl">Fat</td>
+      <td class="tdc">&#8199;4.1</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_466"></a>[Pg 466]</span>
+The quantity of solids and fat in milk is less after longer than after
+shorter periods between milkings.</p>
+
+<p>The quantity of solids and fat in cow milk is less in the spring than
+in the autumn.</p>
+
+<p>The chief organic acid naturally present in milk is citric, which
+exists probably in combination with lime.</p>
+
+<p>The mean content of citric acid in milk is about one-tenth of one per
+cent.<a id="FNanchor_403" href="#Footnote_403" class="fnanchor">[403]</a></p>
+
+<p>Citric acid is not found in human milk, and probably exists only in the
+mammary secretions of herbivores.</p>
+
+<p>Among the mineral acids of milk, phosphoric is the most important, but
+a part of the phosphorus found as phosphoric acid in the ash of milk
+may come from pre-existing organic phosphorus (lecithin, nuclein).</p>
+
+<p>The sulfuric acid, which is found in the ash of milk, is derived from
+the sulfur of the proteid matter during ignition.</p>
+
+<p>Lactic acid is developed from lactose during the souring of milk as the
+result of bacterial activity.</p>
+
+<p>Gases are also found in solutions of milk, notably carbon dioxid, which
+gives to freshly drawn milk its brothy appearance.</p>
+
+<p>The ash of milk has the following composition expressed as grams per
+liter of the original milk:<a id="FNanchor_404" href="#Footnote_404" class="fnanchor">[404]</a></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb">Component.</th>
+      <th class="tdc bb">Grams<br>per liter.</th>
+      <th class="tdc bb">Probable form<br>of combination.</th>
+      <th class="tdc bb">Grams<br>per liter.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl bb" rowspan="2">Chlorin</td>
+      <td class="tdr bb" rowspan="2">0.90</td>
+      <td class="tdl_ws1">sodium chlorid</td>
+      <td class="tdr">0.962</td>
+   </tr><tr>
+      <td class="tdl_ws1 bb">potassium chlorid</td>
+      <td class="tdr bb">0.830</td>
+   </tr><tr>
+      <td class="tdl bb" rowspan="5">Phosphoric acid</td>
+      <td class="tdr bb" rowspan="5">2.42</td>
+      <td class="tdl_ws1">KH₂PO₄</td>
+      <td class="tdr">1.156</td>
+   </tr><tr>
+      <td class="tdl_ws1">K₂HPO₄</td>
+      <td class="tdr">0.853</td>
+   </tr><tr>
+      <td class="tdl_ws1">MgHPO₄</td>
+      <td class="tdr">0.336</td>
+   </tr><tr>
+      <td class="tdl_ws1">CaHPO₄</td>
+      <td class="tdr">0.671</td>
+   </tr><tr>
+      <td class="tdl_ws1 bb">Ca₃(PO₄)₂</td>
+      <td class="tdr bb">0.806</td>
+   </tr><tr>
+      <td class="tdl"></td>
+      <td class="tdr"></td>
+      <td class="tdl_ws1"></td>
+      <td class="tdr"></td>
+   </tr><tr>
+      <td class="tdl bb" rowspan="2">Potassium</td>
+      <td class="tdr bb" rowspan="2">1.80</td>
+      <td class="tdl_ws1">(as shown above)</td>
+      <td class="tdr">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl_ws2 bb">and as potassium citrate</td>
+      <td class="tdr bb">0.495</td>
+   </tr><tr>
+      <td class="tdl bb">Sodium</td>
+      <td class="tdr bb">0.49</td>
+      <td class="tdl_ws1 bb">sodium chlorid</td>
+      <td class="tdr bb">0.962</td>
+
+   </tr><tr>
+      <td class="tdl bb" rowspan="2">Lime</td>
+      <td class="tdr bb" rowspan="2">1.90</td>
+      <td class="tdl_ws1">(as shown above)</td>
+      <td class="tdr">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl_ws2 bb">and as calcium citrate</td>
+      <td class="tdr bb">2.133</td>
+   </tr><tr>
+      <td class="tdl bb">Magnesia</td>
+      <td class="tdr bb">0.20</td>
+      <td class="tdl_ws1 bb">MgHPO₄</td>
+      <td class="tdr bb">0.336</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The percentage composition of the ash of milk, according to Fleischmann
+<span class="pagenum"><a id="Page_467"></a>[Pg 467]</span>
+and Schrott, is expressed as follows:<a id="FNanchor_405" href="#Footnote_405" class="fnanchor">[405]</a></p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdr" colspan="3">Per cent.</td>
+   </tr><tr>
+      <td class="tdl">Potassium oxid,</td>
+      <td class="tdl_wsp fs_105">K₂O</td>
+      <td class="tdr_wsp">25.42</td>
+   </tr><tr>
+      <td class="tdl">Sodium oxid,</td>
+      <td class="tdl_wsp fs_105">Na₂O</td>
+      <td class="tdr_wsp">10.94</td>
+   </tr><tr>
+      <td class="tdl">Calcium oxid,</td>
+      <td class="tdl_wsp fs_105">CaO</td>
+      <td class="tdr_wsp">21.45</td>
+   </tr><tr>
+      <td class="tdl">Magnesium oxid,</td>
+      <td class="tdl_wsp fs_105">MgO</td>
+      <td class="tdr_wsp">2.54</td>
+   </tr><tr>
+      <td class="tdl">Iron oxid,</td>
+      <td class="tdl_wsp fs_105">Fe₂O₃</td>
+      <td class="tdr_wsp">0.11</td>
+   </tr><tr>
+      <td class="tdl">Sulfuric acid,</td>
+      <td class="tdl_wsp fs_105">SO₃</td>
+      <td class="tdr_wsp">4.11</td>
+   </tr><tr>
+      <td class="tdl">Phosphoric acid,</td>
+      <td class="tdl_wsp fs_105">P₂O₅</td>
+      <td class="tdr_wsp">24.11</td>
+   </tr><tr>
+      <td class="tdl">Chlorin,</td>
+      <td class="tdl_wsp fs_105">Cl</td>
+      <td class="tdr_wsp bb">14.60</td>
+   </tr><tr>
+      <td class="tdl" colspan="2">&nbsp;</td>
+      <td class="tdr_wsp">103.28</td>
+   </tr><tr>
+      <td class="tdl">Less</td>
+      <td class="tdl_wsp">Cl as O&emsp;&nbsp;</td>
+      <td class="tdr_wsp bb">3.28</td>
+   </tr><tr>
+      <td class="tdl" colspan="2">&nbsp;</td>
+      <td class="tdr_wsp">100.00</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>428. Alterability of Milk.</b>—The natural souring and coagulation
+of milk is attributed by most authorities to bacterial action produced
+by infection from the air or containing vessels.<a id="FNanchor_406" href="#Footnote_406" class="fnanchor">[406]</a>
+Pasteur, however, shows that fresh milk sterilized at a temperature of
+110° may be exposed to the air without danger of souring.<a id="FNanchor_407" href="#Footnote_407" class="fnanchor">[407]</a>
+After about three days, however, a fermentation is set up which is
+totally different from that produced by the microzymes naturally
+present in the milk. This point has been further investigated by
+Béchamp, who finds that the natural souring of milk is accomplished
+without the evolution of any gas, while the fermentation produced in
+sterilized milk by the microbes of the air, is uniformly attended by a
+gaseous development.<a id="FNanchor_408" href="#Footnote_408" class="fnanchor">[408]</a>
+As a result of his investigations, he concludes that the souring of
+milk takes place spontaneously by reason of milk being an organic
+matter, in the physiological sense of the term, and that this
+alteration is produced solely by the natural microzymes of the milk.</p>
+
+<p>According to Béchamp, the milk derived from healthy animals is capable
+of spontaneous alteration, which consists in the development of lactic
+acid and alcohol, and of curd in those milks which contain caseinates
+produced by the precipitating action of the acids formed. Oxygen and
+the germs which are present in the air, according to him, have nothing
+to do with this alteration in the properties of milk. Milk belongs to
+that class of organic bodies like blood, which are called organic from
+a physiological point of view, on account of containing automatic forces
+<span class="pagenum"><a id="Page_468"></a>[Pg 468]</span>
+which produce rapid changes therein when they are withdrawn from the
+living organisms.</p>
+
+<p>After milk has become sour by the spontaneous action of the microzymes
+which it contains, there are developed micro-organisms, such as
+vibriones and bacteria from a natural evolution from the microzymes.</p>
+
+<p>Milk which is sterilized at a high temperature, <i>viz.</i>, that of
+boiling water or above, is no longer milk in the true physiological
+sense of that term. The globules of the milk undergo changes and
+the microzymes a modification of their functions, so that in milk
+thus altered by heat, they are able to produce a coagulation without
+development of acidity. The microzymes thus modified, however, retain
+to a large extent their ability to become active. Human milk differs
+from cow milk in containing neither caseinates nor casein, but special
+proteid bodies, and also a galactozyme or galactozymase functionally
+very different from that which exists in cow milk. The extractive
+matter is also a special kind, consisting of milk globules and
+microzymes belonging particularly to it and containing three times less
+phosphate and mineral salts than cow milk. Boiling the milk of the cow
+or other animals does not render it similar to that of woman. There is
+no treatment, therefore, of any milk which renders it entirely suited
+to the nourishment of infants. The composition of the milk of the cow
+may be represented by three groups:</p>
+
+<p>1. Organic elements in suspension; consisting chiefly of the globules
+of the milk, which are mostly composed of the fat, of an epidermoid
+membrane containing mineral matter of special soluble albumins and of
+microzymes containing also mineral matter.</p>
+
+<p>2. Dissolved constituents; consisting of caseinates, lactalbuminates,
+galactozymase, holding phosphates in combination, lactose, extractive
+matter, organic phosphates of lime, acetates, urea and alcohol.</p>
+
+<p>3. Mineral matters in solution; consisting of sodium and calcium
+chlorids, carbon dioxid and oxygen.<a id="FNanchor_409" href="#Footnote_409" class="fnanchor">[409]</a></p>
+
+<p>It will be noticed from the above classification that Béchamp fails to
+mention citrate of lime. It is scarcely necessary to add to this brief
+<span class="pagenum"><a id="Page_469"></a>[Pg 469]</span>
+résumé of the theories of Béchamp that they are entirely at variance
+with the opinions held by nearly all his contemporaries.</p>
+
+<p><b>429. Effects of Boiling on Milk.</b>—On boiling, the albumin in
+milk is coagulated and on separating the proteid bodies by saturation
+with magnesium sulfate no albumin is found in the filtrate. The total
+casein precipitated from boiled is therefore greater than from unboiled
+milk. Jager has shown that the casein can be precipitated from boiled
+milk by rennet, but with greater difficulty than from unboiled.<a id="FNanchor_410" href="#Footnote_410" class="fnanchor">[410]</a>
+According to this author in 3.75 per cent of proteid in milk there are
+found 3.15 per cent of casein, 0.35 of albumin and 0.25 of globulin.</p>
+
+<p><b>430. Appearance of the Milk.</b>—The color, taste, odor and other
+sensible characters of the milk are to be observed and noted at the
+time the sample is secured. Any variation from the faint yellow color
+of the milk is due to some abnormal state. A reddish tint indicates
+the admixture of blood, while a blue color is characteristic of the
+presence of unusual micro-organisms. Odor and taste will reveal often
+the character of the food which the animals have eaten. Any marked
+departure of the sample from the properties of normal milk should at
+once lead to its condemnation for culinary or dietetic purposes.</p>
+
+<p><b>431. Micro-Organisms of the Milk.</b>—Milk is a natural culture
+solution for the growth of micro-organisms, and they multiply therein
+with almost incredible rapidity. Some of these are useful, as, for
+instance, those which are active in the ripening of cream, and others
+are of an injurious nature, producing fermentations which destroy the
+sugars or proteids of the milk and develop acid, alcohol, mucous or
+ptomaine products. It is not possible here to even enumerate the kinds
+of micro-organisms which abound in milk and the reader is referred to
+the standard works on that subject.<a id="FNanchor_411" href="#Footnote_411" class="fnanchor">[411]</a></p>
+
+<p>For analytical purposes it is important that the sample be kept as
+free as possible of all micro-organisms, good or bad, which may be
+accomplished by some of the methods given below.</p>
+
+<p><b>432. Sampling Milk.</b>—It is not difficult to secure for
+<span class="pagenum"><a id="Page_470"></a>[Pg 470]</span>
+examination representative samples of milk, if the proper precautions
+be taken. On the other hand, the ease and rapidity with which a milk
+undergoes profound changes render necessary a careful control of the
+methods of taking samples. The most rapid changes to which a mass of
+milk is obnoxious are due to the separation of the fat particles and
+to the action of bacteria. Even after standing for a few minutes, it
+will be found that the fat globules are not evenly distributed. Before
+securing the sample for analysis, it is necessary to well stir or mix
+the milk. A mean sample may also be secured from a can of milk by the
+sampling tube devised by Scovell, which will be described below.</p>
+
+<p>In securing samples, a full detailed description of the cow or herd
+furnishing them is desirable, together with all other data which seem
+to illustrate in any way the general and particular conditions of the
+dairy. Samples are to be preserved in clean, well stoppered vessels,
+properly numbered and securely sealed.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_106" src="images/fig106.jpg" alt="" width="600" height="233" >
+    <p class="center spb1">Fig. 106.—Scovell’s Milk Sampling Tube.</p>
+</div>
+
+<p><b>433. Scovell’s Milk Sampler.</b>—In sampling large quantities of
+milk in pails or shipping cans, it is exceedingly inconvenient to mix
+the milk by pouring from one vessel to another or by any easy process
+of stirring. In order to get representative samples in such conditions,
+Scovell has put in use a sampler, by means of which a typical portion
+of the milk may be withdrawn from a can without either pouring or
+stirring. The construction of the sampler is shown in <a href="#FIG_106">Fig. 106</a>,
+representing it in outline and longitudinal section. The tube <i>a</i>,
+made of brass, is open at both ends and of any convenient dimensions.
+Its lower end slides in a large tube <i>b</i>, closed at the bottom and
+having three elliptical, lateral openings <i>c</i>, which admit the
+milk as the tube is slowly depressed in the contents of the can. In
+<span class="pagenum"><a id="Page_471"></a>[Pg 471]</span>
+getting the sample, <i>a</i> is raised as shown in profile. When the
+bottom of <i>b</i> reaches the bottom of the can <i>a</i> is pushed
+down as shown in the section. The milk contained in the sampler is then
+readily withdrawn.</p>
+
+<p><b>434. Preserving Milk for Analysis.</b>—Pasteurizing or boiling the
+sample is not advisable by reason of the changes produced in the milk
+by heat. The milk sample may be preserved by adding to it a little
+chloroform, one part in 100 being sufficient. Boric and salicylic acids
+may also be used, but not so advantageously as formaldehyd or mercuric
+chlorid. Rideal has observed that one part of formaldehyd will preserve
+10,000 parts of milk in a fresh state for seven days. The formaldehyd
+sold in the trade contains about one part of formaldehyd in 320 of
+the mixture. One-half pint of this commercial article is sufficient
+for about twenty gallons of milk, corresponding to about one part of
+pure formaldehyd to 45,000 parts of milk. Rideal much prefers formalin
+(formaldehyd) to borax or boric acid as a milk preservative. No ill
+effects due to its toxic action have been observed, even when it is
+consumed in a one per cent solution.<a id="FNanchor_412" href="#Footnote_412" class="fnanchor">[412]</a></p>
+
+<p>Samples of milk can be kept in this way from four to six weeks by
+adding about one drop of the commercial formaldehyd to each ounce of
+sample. The analyst should remember in such cases that the formaldehyd
+may not all escape on evaporation, on account of forming some kind of
+a compound with the constituents of the milk, as is pointed out by
+Bevan.<a id="FNanchor_413" href="#Footnote_413" class="fnanchor">[413]</a></p>
+
+<p>Bevan suggests that the formaldehyd may not actually be retained in the
+sample, but that the increase in the apparent amount of total solids
+is due to the conversion of the lactose into galactose. This point,
+however, has not been determined.</p>
+
+<p>Richmond and Boseley propose to detect formalin by means of
+diphenylamin. A solution of diphenylamin is made with water, with the
+help of just enough sulfuric acid to secure a proper solvent effect.
+The liquid to be tested, which is supposed to contain formaldehyd, or
+the distillate therefrom, is added to this solution and boiled. If
+formaldehyd be present, a white flocculent precipitate is deposited,
+which is colored green if the acid used contain nitrates. For other
+methods of detecting formalin and for a partial literature of the
+subject the paper mentioned above may be consulted.
+<span class="pagenum"><a id="Page_472"></a>[Pg 472]</span></p>
+
+<p>One gram of fine-ground mercuric chlorid dissolved in 2,000 grams of
+milk will preserve it, practically unchanged, for several days. One
+gram of potassium bichromate dissolved in one liter of milk will also
+preserve it for some time. Thymol, hydrochloric acid, carbon disulfid,
+ether and other antiseptics may also be employed. No more of the
+preserving agent should be used than is required to keep the milk until
+the analysis is completed.</p>
+
+<p>All methods of preservation are rendered more efficient by the
+maintenance of a low temperature, whereby the vitality of the bacteria
+is greatly reduced.</p>
+
+<p><b>435. Freezing Point of Milk.</b>—By reason of its content of sugar
+and other dissolved solids, the freezing point of milk is depressed
+below 0°. A good idea of the purity of whole milk is secured by
+subjecting it to a kryoscopic test. The apparatus employed for this
+purpose is that used in general analytical work in the determination of
+freezing points. Pure full milk freezes at about 0°.55 below zero, and
+any marked variation from this number shows adulteration or abnormal
+composition.<a id="FNanchor_414" href="#Footnote_414" class="fnanchor">[414]</a>
+A simple apparatus, especially adapted to milk, is described by
+Beckmann.<a id="FNanchor_415" href="#Footnote_415" class="fnanchor">[415]</a>
+The kryoscopic investigation may also be extended to butter fat
+dissolved in benzol.</p>
+
+<p><b>436. Electric Conductivity of Milk.</b>—The electric conductivity
+of milk may also be used as an index of its composition. The addition
+of water to milk diminishes its conductivity.<a id="FNanchor_416" href="#Footnote_416" class="fnanchor">[416]</a>
+This method of investigation has at present but little practical value.</p>
+
+<p><b>437. Viscosity Of Milk.</b>—The viscosity of milk may be determined
+by the methods already described. Any variation from the usual degree
+of fluidity is indicated either by the abstraction of some of the contents
+of the milk, the addition of some adulterant or the result of fermentation.</p>
+
+<p><b>438. Acidity and Alkalinity of Milk.</b>—Fresh milk of normal
+constitution has an amphoteric reaction. It will redden blue and blue
+red litmus paper. This arises from the presence in the milk of both
+neutral and acid phosphates of the alkalies. A saturated alkaline
+phosphate, <i>i. e.</i>, one in which all the acid hydrogen of the acid
+<span class="pagenum"><a id="Page_473"></a>[Pg 473]</span>
+has been replaced by the base has an alkaline reaction while the
+acid phosphates react acid. When fresh milk is boiled its reaction
+becomes strongly alkaline and this arises chiefly from the escape
+of the dissolved carbon dioxid. By the action of micro-organisms on
+the lactose of milk, the alkaline reaction soon becomes acid, and
+delicate test paper will show this decomposition long before it becomes
+perceptible to the taste. It is advisable to test the reactions of the
+milk as soon as possible after it is drawn from the udder, both before
+and after boiling.</p>
+
+<p><b>439. Determination of the Acidity of Milk.</b>—In the determination
+of the acidity of milk it is important that it first be freed of the
+carbon dioxid it contains.<a id="FNanchor_417" href="#Footnote_417" class="fnanchor">[417]</a>
+Van Slyke has found that too high results are obtained by the direct
+titration of milk for acidity, and when the milk is previously diluted
+the results are also somewhat too high.<a id="FNanchor_418" href="#Footnote_418" class="fnanchor">[418]</a>
+Good results are got by diluting the milk with hot water and boiling
+for a short time to expel the carbon dioxid. Twenty-five cubic
+centimeters of milk are diluted with water to about a quarter of a
+liter, as above, two cubic centimeters of a one per cent alcoholic
+phenolphthalien added and the titration accomplished by decinormal
+alkali. This variation of the methods of procedure, suggested by
+Hopkins and Powers, appears to be the best process at present known for
+the determination of acidity. The reader is referred to the paper cited
+above for references to other methods which have been proposed.</p>
+
+<p><b>440. Opacity Of Milk.</b>—The white color and opacity of milk are
+doubtless due to the presence of the suspended fat particles and to
+the colloid casein. On the latter it is probably principally dependent
+since the color of milk is not very sensibly changed after it has
+passed the extractor, which leaves not to exceed one-tenth of one per
+cent of fat in it. Some idea of the quality of the milk, however, may
+be obtained by determining its opacity. This is accomplished by the use
+of a lactoscope. The one generally employed was devised by Feser and is
+shown in <a href="#FIG_107">Fig. 107</a>.</p>
+
+<p>The instrument consists of a cylindrical glass vessel of a little more
+<span class="pagenum"><a id="Page_474"></a>[Pg 474]</span>
+than 100 cubic centimeters content, in the lower part of which is set a
+cone of white glass marked with black lines. Into this part are placed
+four cubic centimeters of milk. A small quantity of water is added and
+the contents of the vessel shaken. This operation is repeated until the
+black lines on the white glass just become visible. The graduations on
+the left side show the volume of water which is necessary to bring the
+dark lines into view, while those on the right indicate approximately
+the percentage of fat present.</p>
+
+<p>Among the other lactoscopes which have been used may be mentioned
+those of Donné, Vogel, Hoppe-Seyler, Trommer, Seidlitz, Reischauer,
+Mittelstrass, Hénocque, and Heusner.<a id="FNanchor_419" href="#Footnote_419" class="fnanchor">[419]</a>
+Since the invention of so many quick and accurate methods of fat
+estimation these instruments have little more than a historical interest.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_107" src="images/fig107.jpg" alt="" width="600" height="268" >
+    <p class="center spb1">Fig. 107.—Lactoscope, Lactometer and Creamometer.</p>
+</div>
+
+<p><b>441. Creamometry.</b>—The volume of cream which a sample of milk
+affords under arbitrary conditions of time and temperature is sometimes
+of value in judging the quality of milk. A convenient creamometer is
+a small cylinder graduated in such a way that the volume of cream
+separated in a given time can be easily noted. There are many kinds of
+apparatus used for this purpose, a typical one being shown in <a href="#FIG_107">Fig. 107</a>.</p>
+
+<p>The usual time of setting is twenty-four hours. A quicker determination
+is secured by placing the milk in strong glass graduated tubes and
+subjecting these to centrifugal action. The process is not exact and
+is now rarely practiced as an analytical method, even for valuing the
+butter making properties of milk.</p>
+
+<p><b>442. Specific Gravity.</b>—The specific gravity of milk is
+uniformly referred to a temperature of 15°. Generally no attempt is made
+<span class="pagenum"><a id="Page_475"></a>[Pg 475]</span>
+to free the milk of dissolved gases beforehand. This should not be
+done by boiling but by placing the sample in a vacuum for some time.
+Any of the methods described for determining specific gravity in sugar
+solutions may be used for milk (<b><a href="#P_48">48-59</a></b>). The specific gravity of
+milk varies in general from 1.028 to 1.034. Nearly all good cow milk
+from herds will show a specific gravity varying from 1.030 to 1.032. In
+extreme cases from single cows the limits may exceed those first given
+above, but such milk cannot be regarded as normal.</p>
+
+<p>Increasing quantities of solids not fat in solution, tend to increase
+the specific gravity, while an excess of fat tends to diminish it.
+There is a general ratio existing between the solids not fat and the
+fat in cow milk, which may be expressed as 9: 4. The removal of
+cream and the addition of water in such a manner as not to affect the
+specific gravity of the sample disturbs this ratio.</p>
+
+<p>The determination of the specific gravity alone, therefore, cannot be
+relied upon as an index of the purity of a milk.</p>
+
+<p><b>443.</b> <b>Lactometry.</b>—A hydrometer especially constructed
+for use in determining the density of milk is called a lactometer. In
+this country the one most commonly used is known as the lactometer
+of the New York Board of Health. It is a hydrometer, delicately
+constructed, with a large cylindrical air space and a small stem
+carrying the thermometric and lactometric scales. It is shown held
+in the creamometer in <a href="#FIG_107">Fig. 107</a>. The milk is brought
+to a temperature of 60° F. and the reading of the lactometer scale
+observed. This is converted into a number expressing the specific
+gravity by means of a table of corresponding values given below. Each
+mark on the scale of the instrument corresponds to two degrees and
+these marks extend from 0° to 120°. The numbers of this scale can be
+converted into those corresponding to the direct reading instrument,
+described in the next paragraph, by multiplying them by 0.29.</p>
+
+<p>The minimum density for whole milk at 60° F. is fixed by this
+instrument at 100°, corresponding to a specific gravity of 1.029. The
+instrument is also constructed without the thermometric scale. The mean
+<span class="pagenum"><a id="Page_476"></a>[Pg 476]</span>
+density of many thousand samples of pure milk, as observed by the New
+York authorities, is 1.0319.</p>
+
+<p>The specific gravity is easily secured, and while not of itself
+decisive, should always be determined. The specific gravity of milk
+increases for some time after it is drawn and should be made both when
+fresh and after the lapse of several hours.<a id="FNanchor_420" href="#Footnote_420" class="fnanchor">[420]</a></p>
+
+<p class="f120"><b><span class="smcap">Table Showing Specific Gravities Corresponding<br>
+to Degrees of the New York Board Of Health<br>Lactometer. Temperature 60° F.</span></b></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb">&nbsp; Degree. &nbsp;</th>
+      <th class="tdc bb">&nbsp; Sp. gr. &nbsp;</th>
+      <th class="tdc bb">&nbsp; Degree. &nbsp;</th>
+      <th class="tdc bb">&nbsp; Sp. gr. &nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">&#8199;90</td>
+      <td class="tdc">1.02619</td>
+      <td class="tdc">106</td>
+      <td class="tdc">1.03074</td>
+   </tr><tr>
+      <td class="tdc">&#8199;91</td>
+      <td class="tdc">1.02639</td>
+      <td class="tdc">107</td>
+      <td class="tdc">1.03103</td>
+   </tr><tr>
+      <td class="tdc">&#8199;92</td>
+      <td class="tdc">1.02668</td>
+      <td class="tdc">108</td>
+      <td class="tdc">1.03132</td>
+   </tr><tr>
+      <td class="tdc">&#8199;93</td>
+      <td class="tdc">1.02697</td>
+      <td class="tdc">109</td>
+      <td class="tdc">1.03161</td>
+   </tr><tr>
+      <td class="tdc">&#8199;94</td>
+      <td class="tdc">1.02726</td>
+      <td class="tdc">110</td>
+      <td class="tdc">1.03190</td>
+   </tr><tr>
+      <td class="tdc">&#8199;95</td>
+      <td class="tdc">1.02755</td>
+      <td class="tdc">111</td>
+      <td class="tdc">1.03219</td>
+   </tr><tr>
+      <td class="tdc">&#8199;96</td>
+      <td class="tdc">1.02784</td>
+      <td class="tdc">112</td>
+      <td class="tdc">1.03248</td>
+   </tr><tr>
+      <td class="tdc">&#8199;97</td>
+      <td class="tdc">1.02813</td>
+      <td class="tdc">113</td>
+      <td class="tdc">1.03277</td>
+   </tr><tr>
+      <td class="tdc">&#8199;98</td>
+      <td class="tdc">1.02842</td>
+      <td class="tdc">114</td>
+      <td class="tdc">1.03306</td>
+   </tr><tr>
+      <td class="tdc">&#8199;99</td>
+      <td class="tdc">1.02871</td>
+      <td class="tdc">115</td>
+      <td class="tdc">1.03335</td>
+   </tr><tr>
+      <td class="tdc">100</td>
+      <td class="tdc">1.02900</td>
+      <td class="tdc">116</td>
+      <td class="tdc">1.03364</td>
+   </tr><tr>
+      <td class="tdc">101</td>
+      <td class="tdc">1.02929</td>
+      <td class="tdc">117</td>
+      <td class="tdc">1.03393</td>
+   </tr><tr>
+      <td class="tdc">102</td>
+      <td class="tdc">1.02958</td>
+      <td class="tdc">118</td>
+      <td class="tdc">1.03422</td>
+   </tr><tr>
+      <td class="tdc">103</td>
+      <td class="tdc">1.02987</td>
+      <td class="tdc">119</td>
+      <td class="tdc">1.03451</td>
+   </tr><tr>
+      <td class="tdc">104</td>
+      <td class="tdc">1.03016</td>
+      <td class="tdc">120</td>
+      <td class="tdc">1.03480</td>
+   </tr><tr>
+      <td class="tdc">105</td>
+      <td class="tdc">1.03045</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>444.</b> <b>Direct Reading Lactometer.</b>—A more convenient form
+of lactometer is one which gives the specific gravity directly on the
+scale. The figures given represent those found in the second and third
+decimal places of the number expressing the specific gravity. Thus 31
+on the scale indicates a specific gravity of 1.031. This instrument is
+also known as the lactometer of Quévenne. For use with milk, the scale
+of the instrument does not need to embrace a wider limit than from
+25 to 35, and such an instrument is capable of giving more delicate
+readings than when the scale extends from 14 to 42, as is usually the
+case with the quévenne instrument.</p>
+
+<p>Langlet has invented a lactoscope with a scale, showing the corrections
+to be applied for temperatures other than 15°. A detailed description
+of this instrument, as well as the one proposed by Pinchon, is
+unnecessary.<a id="FNanchor_421" href="#Footnote_421" class="fnanchor">[421]</a></p>
+
+<p><span class="pagenum"><a id="Page_477"></a>[Pg 477]</span>
+<b>445. Density of Sour Milk.</b>—Coagulated milk cannot be used
+directly for the determination of the specific gravity, both because of
+its consistence and by reason of the fact that the fat is more or less
+completely separated. In such a case, the casein may be dissolved by
+the addition of a measured quantity of a solvent of a known specific
+gravity, the density of the resulting solution determined and that
+of the original milk calculated from the observed data. Ammonia is a
+suitable solvent for this purpose.<a id="FNanchor_422" href="#Footnote_422" class="fnanchor">[422]</a></p>
+
+<p><b>446. Density of the Milk Serum.</b>—The specific gravity of the
+milk serum, after the removal of the fat and casein by precipitation
+and filtration, may also be determined. For normal cow milk the number
+is about 1.027.</p>
+
+<p id="P_447"><b>447. Total Solids.</b>—The direct gravimetric determination of the
+total solids in milk is attended with many difficulties, and has been
+the theme of a very extended periodical literature. A mere examination
+of the many processes which have been proposed would require several
+pages.</p>
+
+<p>The most direct method of procedure is to dry a small quantity of milk
+in a flat-bottom dish to constant weight on a steam-bath. The surface
+of the dish should be very large, even for one or two grams of milk;
+in fact the relation between the quantity of milk and the surface of
+the dish should be such that the fluid is just sufficient in amount to
+moisten the bottom of the dish with the thinnest possible film. The
+dish, during drying, is kept in a horizontal position at least until
+its contents will not flow. The water of the sample will be practically
+all evaporated in about two hours. The operation may be accelerated by
+drying in vacuo.</p>
+
+<p>The drying may also be accomplished by using a flat-bottom dish
+containing some absorbent, such as sand, pumice stone, asbestos or
+crysolite. The milk may also be absorbed by a dried paper coil and
+dried thereon (<b><a href="#P_26">26</a></b>).</p>
+
+<p>It is convenient to determine the water in the sample subsequently
+to be used for the gravimetric determination of the fat, and this is
+secured by the adoption of the paper coil method, as suggested by the
+author, or by the use of a perforated metal tube containing porous
+asbestos, as proposed by Babcock.<a id="FNanchor_423" href="#Footnote_423" class="fnanchor">[423]</a></p>
+
+<p><span class="pagenum"><a id="Page_478"></a>[Pg 478]</span>
+The process is conveniently carried out as follows:</p>
+
+<p>Provide a hollow cylinder of perforated sheet metal sixty millimeters
+long and twenty millimeters in diameter, closed five millimeters from
+one end by a disk of the same material. The perforations should be
+about 0.7 millimeter in diameter and as close together as possible.
+Fill loosely with from one and a half to two and a half grams of dry
+woolly asbestos and weigh. Introduce a weighed quantity of milk (about
+five grams). Dry at 100° for four hours. During the first part of the
+drying the door of the oven should be left partly open to allow escape
+of moisture. Cool in a desiccator and weigh. Repeat the drying until
+the weight remains constant. Place in an extractor and treat with
+anhydrous ether for two hours. Evaporate the ether and dry the fat at
+100°. The extracted fat is weighed and the number thus obtained may be
+checked by drying and weighing the cylinder containing the residue.</p>
+
+<p>The asbestos best suited for use in this process should be of a woolly
+nature, quite absorbent, and, previous to use, be ignited to free it
+of moisture and organic matter. A variety of serpentine, crysolite is
+sometimes used instead of asbestos. When the content of water alone is
+desired, it is accurately determined by drying in vacuo over pumice
+stone (<a href="#Page_33">page 33</a>).</p>
+
+<p>The methods above mentioned are typical and will prove a sufficient
+guide for conducting the desiccation, either as described or by any
+modification of the methods which may be preferred.</p>
+
+<p><b>448. Calculation of Total Solids.</b>—By reason of the ease and
+celerity with which the density of a milk and its content of fat
+can be obtained, analysts have found it convenient to calculate the
+percentage of total solids instead of determining it directly. This
+is accomplished by arbitrary formulas based on the data of numerous
+analyses. These formulas give satisfactory results when the samples do
+not vary widely from the normal and may be used with advantage in most cases.</p>
+
+<p>Among the earliest formulas for the calculation may be mentioned those
+of Fleischmann and Morgen,<a id="FNanchor_424" href="#Footnote_424" class="fnanchor">[424]</a>
+Behrend and Morgen,<a id="FNanchor_425" href="#Footnote_425" class="fnanchor">[425]</a>
+Claus, Stutzer and Meyer,<a id="FNanchor_426" href="#Footnote_426" class="fnanchor">[426]</a> Hehner,<a id="FNanchor_427" href="#Footnote_427" class="fnanchor">[427]</a>
+and Hehner and Richmond.<a id="FNanchor_428" href="#Footnote_428" class="fnanchor">[428]</a>
+Without doing more than citing these papers it will be sufficient here
+<span class="pagenum"><a id="Page_479"></a>[Pg 479]</span>
+to give the formulas as corrected by the most recent experience.</p>
+
+<p>In the formula worked out by Babcock the specific gravity of the sample
+is represented by <i>S</i>, the fat by <i>F</i>, and the solids not fat
+by <i>t</i>. The formula is written as follows:<a id="FNanchor_429" href="#Footnote_429" class="fnanchor">[429]</a></p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>t</i> = <span class="fs_200">(</span>&nbsp;</td>
+      <td class="tdc bb">100<i>S</i> - <i>FS</i></td>
+      <td class="tdl" rowspan="2"><span class="fs_200">&nbsp;)</span>
+                                  (250 - 2.5 <i>F</i>).</td>
+   </tr><tr>
+      <td class="tdc">100 - 1.0753<i>FS</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p>In this formula it is assumed that the difference between the specific
+gravity of the milk serum and that of water is directly proportional
+to the per cent of solids in the serum, but this assumption is not
+strictly correct. Even in extreme cases, however, the error does not
+amount to more than 0.05 per cent.</p>
+
+<p>Since a given amount of milk sugar increases the density of a milk
+more than the same quantity of casein, it is evident that the formula
+would not apply to those instances in which the ratio between these two
+ingredients is greatly disturbed, as for instance, the whey.</p>
+
+<p>The formula of Hehner and Richmond, in its latest form, is expressed as
+follows:</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>T</i> = 0.2625 &nbsp;</td>
+      <td class="tdc bb">&nbsp;<i>G</i>&nbsp;</td>
+      <td class="tdl" rowspan="2">&nbsp; + 1.2<i>F</i>,</td>
+   </tr><tr>
+      <td class="tdc"><i>D</i></td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="no-indent">in which <i>T</i> represents the total solids,
+<i>G</i> the reading of the quévenne lactometer, <i>D</i> the specific
+gravity, and <i>F</i> the fat.</p>
+
+<div class="blockquot">
+<p><i>Example.</i>—Let the reading of the lactometer be 31, corresponding
+to <i>D</i> 1.031, and the percentage of fat be three and five-tenths,
+what is the percentage of the total solids?</p>
+
+<p>Substituting these values in the formulas we have</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>T</i> = 0.2625 &nbsp;</td>
+      <td class="tdc bb">31</td>
+      <td class="tdl" rowspan="2">&nbsp; + 1.2 × 3.5 = 12.09.</td>
+   </tr><tr>
+      <td class="tdc">1.031</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>To simplify the calculations, Richmond’s formula may be written</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>T</i> = &nbsp;</td>
+      <td class="tdc bb">&nbsp;<i>G</i>&nbsp;</td>
+      <td class="tdl" rowspan="2">&nbsp; + &nbsp;</td>
+      <td class="tdc bb">&nbsp;6<i>F</i>&nbsp;</td>
+      <td class="tdl" rowspan="2">&nbsp; + 0.14.</td>
+   </tr><tr>
+      <td class="tdc">4</td>
+      <td class="tdc">5</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Calculated by this shortened formula from the above data <i>T</i> =
+12.09, the same as given in the larger formula.</p>
+</div>
+
+<p>Calculating the solids not fat in the hypothetical case given above
+by Babcock’s formula, we get <i>t</i> = 8.46, and this plus 3.5 gives 11.96,
+which is slightly lower than the number obtained by the richmond process.
+<span class="pagenum"><a id="Page_480"></a>[Pg 480]</span></p>
+
+<p>The babcock formula may be simplified by substituting the number
+expressing the reading of the quévenne lactometer for that donating the
+specific gravity, in other words, the specific gravity multiplied by
+100 and the quotient diminished by 1000.</p>
+
+<p>The formulas for solids not fat and total solids then become</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>t</i> = &nbsp;</td>
+      <td class="tdc bb">&nbsp;<i>L</i>&nbsp;</td>
+      <td class="tdl" rowspan="2">&nbsp;+ 0.2<i>F</i>,&emsp;and&emsp;<i>T</i> = &nbsp;</td>
+      <td class="tdc bb">&nbsp;<i>L</i>&nbsp;</td>
+      <td class="tdl" rowspan="2">&nbsp; + 1.2<i>F</i>,</td>
+   </tr><tr>
+      <td class="tdc">4</td>
+      <td class="tdc">4</td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="no-indent">in which <i>L</i> represents the reading of the
+lactometer. By the addition of the constant factor 0.14 the results
+calculated by the formula of Babcock are the same as those obtained by
+the method of Richmond.</p>
+
+<p>In the following table are given the solids not fat in milks as
+calculated by Babcock’s formula. To obtain the total solids add the
+per cent of fat to solids not fat. To obtain total solids according to
+Richmond’s formula increase that number by 0.14.</p>
+
+<p class="f120"><b><span class="smcap">Table Showing Per Cent of Solids not Fat in Milk<br>
+Corresponding to Quévenne’s Lactometer Readings<br>and Per Cent of Fat.</span></b></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bt">Per<br>cent</th>
+      <th class="tdc bb bl bt" colspan="11">Lactometer reading at 60° F.</th>
+   </tr><tr>
+      <th class="tdc bb br">&nbsp;of fat.&nbsp;</th>
+      <th class="tdc bb">&nbsp; &nbsp;26.&nbsp; &nbsp;</th> <th class="tdc bb">&nbsp; &nbsp;27.&nbsp; &nbsp;</th>
+      <th class="tdc bb">&nbsp; &nbsp;28.&nbsp; &nbsp;</th> <th class="tdc bb">&nbsp; &nbsp;29.&nbsp; &nbsp;</th>
+      <th class="tdc bb">&nbsp; &nbsp;30.&nbsp; &nbsp;</th> <th class="tdc bb">&nbsp; &nbsp;31.&nbsp; &nbsp;</th>
+      <th class="tdc bb">&nbsp; &nbsp;32.&nbsp; &nbsp;</th> <th class="tdc bb">&nbsp; &nbsp;33.&nbsp; &nbsp;</th>
+      <th class="tdc bb">&nbsp; &nbsp;34.&nbsp; &nbsp;</th> <th class="tdc bb">&nbsp; &nbsp;35.&nbsp; &nbsp;</th>
+      <th class="tdc bb">&nbsp; &nbsp;36&nbsp;. &nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">0.0</td> <td class="tdc">6.50</td>
+      <td class="tdc">6.75</td> <td class="tdc">7.00</td>
+      <td class="tdc">7.25</td> <td class="tdc">7.50</td>
+      <td class="tdc">7.75</td> <td class="tdc">8.00</td>
+      <td class="tdc">8.25</td> <td class="tdc">8.50</td>
+      <td class="tdc">8.75</td> <td class="tdc">9.00</td>
+   </tr><tr>
+      <td class="tdc">0.1</td> <td class="tdc">6.52</td>
+      <td class="tdc">6.77</td> <td class="tdc">7.02</td>
+      <td class="tdc">7.27</td> <td class="tdc">7.52</td>
+      <td class="tdc">7.77</td> <td class="tdc">8.02</td>
+      <td class="tdc">8.27</td> <td class="tdc">8.52</td>
+      <td class="tdc">8.77</td> <td class="tdc">9.02</td>
+   </tr><tr>
+      <td class="tdc">0.2</td> <td class="tdc">6.54</td>
+      <td class="tdc">6.79</td> <td class="tdc">7.04</td>
+      <td class="tdc">7.29</td> <td class="tdc">7.54</td>
+      <td class="tdc">7.79</td> <td class="tdc">8.04</td>
+      <td class="tdc">8.29</td> <td class="tdc">8.54</td>
+      <td class="tdc">8.79</td> <td class="tdc">9.04</td>
+   </tr><tr>
+      <td class="tdc">0.3</td> <td class="tdc">6.56</td>
+      <td class="tdc">6.81</td> <td class="tdc">7.06</td>
+      <td class="tdc">7.31</td> <td class="tdc">7.56</td>
+      <td class="tdc">7.81</td> <td class="tdc">8.06</td>
+      <td class="tdc">8.31</td> <td class="tdc">8.56</td>
+      <td class="tdc">8.81</td> <td class="tdc">9.06</td>
+   </tr><tr>
+      <td class="tdc">0.4</td> <td class="tdc">6.58</td>
+      <td class="tdc">6.83</td> <td class="tdc">7.08</td>
+      <td class="tdc">7.33</td> <td class="tdc">7.58</td>
+      <td class="tdc">7.83</td> <td class="tdc">8.08</td>
+      <td class="tdc">8.33</td> <td class="tdc">8.58</td>
+      <td class="tdc">8.83</td> <td class="tdc">9.08</td>
+   </tr><tr>
+      <td class="tdc">0.5</td> <td class="tdc">6.60</td>
+      <td class="tdc">6.85</td> <td class="tdc">7.10</td>
+      <td class="tdc">7.35</td> <td class="tdc">7.60</td>
+      <td class="tdc">7.85</td> <td class="tdc">8.10</td>
+      <td class="tdc">8.35</td> <td class="tdc">8.60</td>
+      <td class="tdc">8.85</td> <td class="tdc">9.10</td>
+   </tr><tr>
+      <td class="tdc">0.6</td> <td class="tdc">6.62</td>
+      <td class="tdc">6.87</td> <td class="tdc">7.12</td>
+      <td class="tdc">7.37</td> <td class="tdc">7.62</td>
+      <td class="tdc">7.87</td> <td class="tdc">8.12</td>
+      <td class="tdc">8.37</td> <td class="tdc">8.62</td>
+      <td class="tdc">8.87</td> <td class="tdc">9.12</td>
+   </tr><tr>
+      <td class="tdc">0.7</td> <td class="tdc">6.64</td>
+      <td class="tdc">6.89</td> <td class="tdc">7.14</td>
+      <td class="tdc">7.39</td> <td class="tdc">7.64</td>
+      <td class="tdc">7.89</td> <td class="tdc">8.14</td>
+      <td class="tdc">8.39</td> <td class="tdc">8.64</td>
+      <td class="tdc">8.89</td> <td class="tdc">9.14</td>
+   </tr><tr>
+      <td class="tdc">0.8</td> <td class="tdc">6.66</td>
+      <td class="tdc">6.91</td> <td class="tdc">7.16</td>
+      <td class="tdc">7.41</td> <td class="tdc">7.66</td>
+      <td class="tdc">7.91</td> <td class="tdc">8.16</td>
+      <td class="tdc">8.41</td> <td class="tdc">8.66</td>
+      <td class="tdc">8.91</td> <td class="tdc">9.16</td>
+   </tr><tr>
+      <td class="tdc bb">0.9</td> <td class="tdc bb">6.68</td>
+      <td class="tdc bb">6.93</td> <td class="tdc bb">7.18</td>
+      <td class="tdc bb">7.43</td> <td class="tdc bb">7.68</td>
+      <td class="tdc bb">7.93</td> <td class="tdc bb">8.18</td>
+      <td class="tdc bb">8.43</td> <td class="tdc bb">8.68</td>
+      <td class="tdc bb">8.93</td> <td class="tdc bb">9.18</td>
+   </tr><tr>
+      <td class="tdc">1.0</td> <td class="tdc">6.70</td>
+      <td class="tdc">6.95</td> <td class="tdc">7.20</td>
+      <td class="tdc">7.45</td> <td class="tdc">7.70</td>
+      <td class="tdc">7.95</td> <td class="tdc">8.20</td>
+      <td class="tdc">8.45</td> <td class="tdc">8.70</td>
+      <td class="tdc">8.95</td> <td class="tdc">9.20</td>
+   </tr><tr>
+      <td class="tdc">1.1</td> <td class="tdc">6.72</td>
+      <td class="tdc">6.97</td> <td class="tdc">7.22</td>
+      <td class="tdc">7.47</td> <td class="tdc">7.72</td>
+      <td class="tdc">7.97</td> <td class="tdc">8.22</td>
+      <td class="tdc">8.47</td> <td class="tdc">8.72</td>
+      <td class="tdc">8.97</td> <td class="tdc">9.22</td>
+   </tr><tr>
+      <td class="tdc">1.2</td> <td class="tdc">6.74</td>
+      <td class="tdc">6.99</td> <td class="tdc">7.24</td>
+      <td class="tdc">7.49</td> <td class="tdc">7.74</td>
+      <td class="tdc">7.99</td> <td class="tdc">8.24</td>
+      <td class="tdc">8.49</td> <td class="tdc">8.74</td>
+      <td class="tdc">8.99</td> <td class="tdc">9.24</td>
+   </tr><tr>
+      <td class="tdc">1.3</td> <td class="tdc">6.76</td>
+      <td class="tdc">7.01</td> <td class="tdc">7.26</td>
+      <td class="tdc">7.51</td> <td class="tdc">7.76</td>
+      <td class="tdc">8.01</td> <td class="tdc">8.26</td>
+      <td class="tdc">8.51</td> <td class="tdc">8.76</td>
+      <td class="tdc">9.01</td> <td class="tdc">9.26</td>
+   </tr><tr>
+      <td class="tdc">1.4</td> <td class="tdc">6.78</td>
+      <td class="tdc">7.03</td> <td class="tdc">7.28</td>
+      <td class="tdc">7.53</td> <td class="tdc">7.78</td>
+      <td class="tdc">8.03</td> <td class="tdc">8.28</td>
+      <td class="tdc">8.53</td> <td class="tdc">8.78</td>
+      <td class="tdc">9.03</td> <td class="tdc">9.28</td>
+   </tr><tr>
+      <td class="tdc">1.5</td> <td class="tdc">6.80</td>
+      <td class="tdc">7.05</td> <td class="tdc">7.30</td>
+      <td class="tdc">7.55</td> <td class="tdc">7.80</td>
+      <td class="tdc">8.05</td> <td class="tdc">8.30</td>
+      <td class="tdc">8.55</td> <td class="tdc">8.80</td>
+      <td class="tdc">9.05</td> <td class="tdc">9.30</td>
+   </tr><tr>
+      <td class="tdc">1.6</td> <td class="tdc">6.82</td>
+      <td class="tdc">7.07</td> <td class="tdc">7.32</td>
+      <td class="tdc">7.57</td> <td class="tdc">7.82</td>
+      <td class="tdc">8.07</td> <td class="tdc">8.32</td>
+      <td class="tdc">8.57</td> <td class="tdc">8.82</td>
+      <td class="tdc">9.07</td> <td class="tdc">9.32</td>
+   </tr><tr>
+      <td class="tdc">1.7</td> <td class="tdc">6.84</td>
+      <td class="tdc">7.09</td> <td class="tdc">7.34</td>
+      <td class="tdc">7.59</td> <td class="tdc">7.84</td>
+      <td class="tdc">8.09</td> <td class="tdc">8.34</td>
+      <td class="tdc">8.59</td> <td class="tdc">8.84</td>
+      <td class="tdc">9.09</td> <td class="tdc">9.34</td>
+   </tr><tr>
+      <td class="tdc">1.8</td> <td class="tdc">6.86</td>
+      <td class="tdc">7.11</td> <td class="tdc">7.36</td>
+      <td class="tdc">7.61</td> <td class="tdc">7.86</td>
+      <td class="tdc">8.11</td> <td class="tdc">8.36</td>
+      <td class="tdc">8.61</td> <td class="tdc">8.86</td>
+      <td class="tdc">9.11</td> <td class="tdc">9.37</td>
+   </tr><tr>
+      <td class="tdc bb">1.9</td> <td class="tdc bb">6.88</td>
+      <td class="tdc bb">7.13</td> <td class="tdc bb">7.38</td>
+      <td class="tdc bb">7.63</td> <td class="tdc bb">7.88</td>
+      <td class="tdc bb">8.13</td> <td class="tdc bb">8.38</td>
+      <td class="tdc bb">8.63</td> <td class="tdc bb">8.88</td>
+      <td class="tdc bb">9.14</td> <td class="tdc bb">9.39</td>
+   </tr><tr>
+      <td class="tdc">2.0</td> <td class="tdc">6.90</td>
+      <td class="tdc">7.15</td> <td class="tdc">7.40</td>
+      <td class="tdc">7.65</td> <td class="tdc">7.90</td>
+      <td class="tdc">8.15</td> <td class="tdc">8.40</td>
+      <td class="tdc">8.66</td> <td class="tdc">8.91</td>
+      <td class="tdc">9.16</td> <td class="tdc">9.41
+                   <span class="pagenum"><a id="Page_481"></a>[Pg 481]</span></td>
+   </tr><tr>
+      <td class="tdc">2.1</td> <td class="tdc">6.92</td>
+      <td class="tdc">7.17</td> <td class="tdc">7.42</td>
+      <td class="tdc">7.67</td> <td class="tdc">7.92</td>
+      <td class="tdc">8.17</td> <td class="tdc">8.42</td>
+      <td class="tdc">8.68</td> <td class="tdc">8.93</td>
+      <td class="tdc">9.18</td> <td class="tdc">9.43</td>
+   </tr><tr>
+      <td class="tdc">2.2</td> <td class="tdc">6.94</td>
+      <td class="tdc">7.19</td> <td class="tdc">7.44</td>
+      <td class="tdc">7.69</td> <td class="tdc">7.94</td>
+      <td class="tdc">8.19</td> <td class="tdc">8.44</td>
+      <td class="tdc">8.70</td> <td class="tdc">8.95</td>
+      <td class="tdc">9.20</td> <td class="tdc">9.45</td>
+   </tr><tr>
+      <td class="tdc">2.3</td> <td class="tdc">6.96</td>
+      <td class="tdc">7.21</td> <td class="tdc">7.46</td>
+      <td class="tdc">7.71</td> <td class="tdc">7.96</td>
+      <td class="tdc">8.21</td> <td class="tdc">8.46</td>
+      <td class="tdc">8.72</td> <td class="tdc">8.97</td>
+      <td class="tdc">9.22</td> <td class="tdc">9.47</td>
+   </tr><tr>
+      <td class="tdc">2.4</td> <td class="tdc">6.98</td>
+      <td class="tdc">7.23</td> <td class="tdc">7.48</td>
+      <td class="tdc">7.73</td> <td class="tdc">7.98</td>
+      <td class="tdc">8.23</td> <td class="tdc">8.48</td>
+      <td class="tdc">8.74</td> <td class="tdc">8.99</td>
+      <td class="tdc">9.24</td> <td class="tdc">9.49</td>
+   </tr><tr>
+      <td class="tdc">2.5</td> <td class="tdc">7.00</td>
+      <td class="tdc">7.25</td> <td class="tdc">7.50</td>
+      <td class="tdc">7.75</td> <td class="tdc">8.00</td>
+      <td class="tdc">8.25</td> <td class="tdc">8.50</td>
+      <td class="tdc">8.76</td> <td class="tdc">9.01</td>
+      <td class="tdc">9.26</td> <td class="tdc">9.51</td>
+   </tr><tr>
+      <td class="tdc">2.6</td> <td class="tdc">7.02</td>
+      <td class="tdc">7.27</td> <td class="tdc">7.52</td>
+      <td class="tdc">7.77</td> <td class="tdc">8.02</td>
+      <td class="tdc">8.27</td> <td class="tdc">8.52</td>
+      <td class="tdc">8.78</td> <td class="tdc">9.03</td>
+      <td class="tdc">9.28</td> <td class="tdc">9.53</td>
+   </tr><tr>
+      <td class="tdc">2.7</td> <td class="tdc">7.04</td>
+      <td class="tdc">7.29</td> <td class="tdc">7.54</td>
+      <td class="tdc">7.79</td> <td class="tdc">8.04</td>
+      <td class="tdc">8.29</td> <td class="tdc">8.54</td>
+      <td class="tdc">8.80</td> <td class="tdc">9.05</td>
+      <td class="tdc">9.30</td> <td class="tdc">9.55</td>
+   </tr><tr>
+      <td class="tdc">2.8</td> <td class="tdc">7.06</td>
+      <td class="tdc">7.31</td> <td class="tdc">7.56</td>
+      <td class="tdc">7.81</td> <td class="tdc">8.06</td>
+      <td class="tdc">8.31</td> <td class="tdc">8.57</td>
+      <td class="tdc">8.82</td> <td class="tdc">9.07</td>
+      <td class="tdc">9.32</td> <td class="tdc">9.57</td>
+   </tr><tr>
+      <td class="tdc bb">2.9</td> <td class="tdc bb">7.08</td>
+      <td class="tdc bb">7.33</td> <td class="tdc bb">7.58</td>
+      <td class="tdc bb">7.83</td> <td class="tdc bb">8.08</td>
+      <td class="tdc bb">8.33</td> <td class="tdc bb">8.59</td>
+      <td class="tdc bb">8.84</td> <td class="tdc bb">9.09</td>
+      <td class="tdc bb">9.34</td> <td class="tdc bb">9.59</td>
+   </tr><tr>
+      <td class="tdc">3.0</td> <td class="tdc">7.10</td>
+      <td class="tdc">7.35</td> <td class="tdc">7.60</td>
+      <td class="tdc">7.85</td> <td class="tdc">8.10</td>
+      <td class="tdc">8.36</td> <td class="tdc">8.61</td>
+      <td class="tdc">8.86</td> <td class="tdc">9.11</td>
+      <td class="tdc">9.36</td> <td class="tdc">9.61</td>
+   </tr><tr>
+      <td class="tdc">3.1</td> <td class="tdc">7.12</td>
+      <td class="tdc">7.37</td> <td class="tdc">7.62</td>
+      <td class="tdc">7.87</td> <td class="tdc">8.13</td>
+      <td class="tdc">8.38</td> <td class="tdc">8.63</td>
+      <td class="tdc">8.88</td> <td class="tdc">9.13</td>
+      <td class="tdc">9.38</td> <td class="tdc">9.64</td>
+   </tr><tr>
+      <td class="tdc">3.2</td> <td class="tdc">7.14</td>
+      <td class="tdc">7.39</td> <td class="tdc">7.64</td>
+      <td class="tdc">7.89</td> <td class="tdc">8.15</td>
+      <td class="tdc">8.40</td> <td class="tdc">8.65</td>
+      <td class="tdc">8.90</td> <td class="tdc">9.15</td>
+      <td class="tdc">9.41</td> <td class="tdc">9.66</td>
+   </tr><tr>
+      <td class="tdc">3.3</td> <td class="tdc">7.16</td>
+      <td class="tdc">7.41</td> <td class="tdc">7.66</td>
+      <td class="tdc">7.92</td> <td class="tdc">8.17</td>
+      <td class="tdc">8.42</td> <td class="tdc">8.67</td>
+      <td class="tdc">8.92</td> <td class="tdc">9.18</td>
+      <td class="tdc">9.43</td> <td class="tdc">9.68</td>
+   </tr><tr>
+      <td class="tdc">3.4</td> <td class="tdc">7.18</td>
+      <td class="tdc">7.43</td> <td class="tdc">7.69</td>
+      <td class="tdc">7.94</td> <td class="tdc">8.19</td>
+      <td class="tdc">8.44</td> <td class="tdc">8.69</td>
+      <td class="tdc">8.94</td> <td class="tdc">9.20</td>
+      <td class="tdc">9.45</td> <td class="tdc">9.70</td>
+   </tr><tr>
+      <td class="tdc">3.5</td> <td class="tdc">7.20</td>
+      <td class="tdc">7.45</td> <td class="tdc">7.71</td>
+      <td class="tdc">7.96</td> <td class="tdc">8.21</td>
+      <td class="tdc">8.46</td> <td class="tdc">8.71</td>
+      <td class="tdc">8.96</td> <td class="tdc">9.22</td>
+      <td class="tdc">9.47</td> <td class="tdc">9.72</td>
+   </tr><tr>
+      <td class="tdc">3.6</td> <td class="tdc">7.22</td>
+      <td class="tdc">7.48</td> <td class="tdc">7.73</td>
+      <td class="tdc">7.98</td> <td class="tdc">8.23</td>
+      <td class="tdc">8.48</td> <td class="tdc">8.73</td>
+      <td class="tdc">8.98</td> <td class="tdc">9.24</td>
+      <td class="tdc">9.49</td> <td class="tdc">9.74</td>
+   </tr><tr>
+      <td class="tdc">3.7</td> <td class="tdc">7.24</td>
+      <td class="tdc">7.50</td> <td class="tdc">7.75</td>
+      <td class="tdc">8.00</td> <td class="tdc">8.25</td>
+      <td class="tdc">8.50</td> <td class="tdc">8.75</td>
+      <td class="tdc">9.00</td> <td class="tdc">9.26</td>
+      <td class="tdc">9.51</td> <td class="tdc">9.76</td>
+   </tr><tr>
+      <td class="tdc">3.8</td> <td class="tdc">7.26</td>
+      <td class="tdc">7.52</td> <td class="tdc">7.77</td>
+      <td class="tdc">8.02</td> <td class="tdc">8.27</td>
+      <td class="tdc">8.52</td> <td class="tdc">8.77</td>
+      <td class="tdc">9.02</td> <td class="tdc">9.28</td>
+      <td class="tdc">9.53</td> <td class="tdc">9.78</td>
+   </tr><tr>
+      <td class="tdc bb">3.9</td> <td class="tdc bb">7.28</td>
+      <td class="tdc bb">7.54</td> <td class="tdc bb">7.79</td>
+      <td class="tdc bb">8.04</td> <td class="tdc bb">8.29</td>
+      <td class="tdc bb">8.54</td> <td class="tdc bb">8.79</td>
+      <td class="tdc bb">9.04</td> <td class="tdc bb">9.30</td>
+      <td class="tdc bb">9.55</td> <td class="tdc bb">9.80</td>
+   </tr><tr>
+      <td class="tdc">4.0</td> <td class="tdc">7.30</td>
+      <td class="tdc">7.56</td> <td class="tdc">7.81</td>
+      <td class="tdc">8.06</td> <td class="tdc">8.31</td>
+      <td class="tdc">8.56</td> <td class="tdc">8.81</td>
+      <td class="tdc">9.06</td> <td class="tdc">9.32</td>
+      <td class="tdc">9.57</td> <td class="tdc">9.83</td>
+   </tr><tr>
+      <td class="tdc">4.1</td> <td class="tdc">7.32</td>
+      <td class="tdc">7.58</td> <td class="tdc">7.83</td>
+      <td class="tdc">8.08</td> <td class="tdc">8.33</td>
+      <td class="tdc">8.58</td> <td class="tdc">8.83</td>
+      <td class="tdc">9.08</td> <td class="tdc">9.34</td>
+      <td class="tdc">9.59</td> <td class="tdc">9.85</td>
+   </tr><tr>
+      <td class="tdc">4.2</td> <td class="tdc">7.34</td>
+      <td class="tdc">7.60</td> <td class="tdc">7.85</td>
+      <td class="tdc">8.10</td> <td class="tdc">8.35</td>
+      <td class="tdc">8.60</td> <td class="tdc">8.85</td>
+      <td class="tdc">9.11</td> <td class="tdc">9.36</td>
+      <td class="tdc">9.62</td> <td class="tdc">9.87</td>
+   </tr><tr>
+      <td class="tdc">4.3</td> <td class="tdc">7.36</td>
+      <td class="tdc">7.62</td> <td class="tdc">7.87</td>
+      <td class="tdc">8.12</td> <td class="tdc">8.37</td>
+      <td class="tdc">8.62</td> <td class="tdc">8.88</td>
+      <td class="tdc">9.13</td> <td class="tdc">9.38</td>
+      <td class="tdc">9.64</td> <td class="tdc">9.89</td>
+   </tr><tr>
+      <td class="tdc">4.4</td> <td class="tdc">7.38</td>
+      <td class="tdc">7.64</td> <td class="tdc">7.89</td>
+      <td class="tdc">8.14</td> <td class="tdc">8.39</td>
+      <td class="tdc">8.64</td> <td class="tdc">8.90</td>
+      <td class="tdc">9.15</td> <td class="tdc">9.40</td>
+      <td class="tdc">9.66</td> <td class="tdc">9.91</td>
+   </tr><tr>
+      <td class="tdc">4.5</td> <td class="tdc">7.40</td>
+      <td class="tdc">7.66</td> <td class="tdc">7.91</td>
+      <td class="tdc">8.16</td> <td class="tdc">8.41</td>
+      <td class="tdc">8.66</td> <td class="tdc">8.92</td>
+      <td class="tdc">9.17</td> <td class="tdc">9.42</td>
+      <td class="tdc">9.68</td> <td class="tdc">9.93</td>
+   </tr><tr>
+      <td class="tdc">4.6</td> <td class="tdc">7.43</td>
+      <td class="tdc">7.68</td> <td class="tdc">7.93</td>
+      <td class="tdc">8.18</td> <td class="tdc">8.43</td>
+      <td class="tdc">8.68</td> <td class="tdc">8.94</td>
+      <td class="tdc">9.19</td> <td class="tdc">9.44</td>
+      <td class="tdc">9.70</td> <td class="tdc">9.95</td>
+   </tr><tr>
+      <td class="tdc">4.7</td> <td class="tdc">7.45</td>
+      <td class="tdc">7.70</td> <td class="tdc">7.95</td>
+      <td class="tdc">8.20</td> <td class="tdc">8.45</td>
+      <td class="tdc">8.70</td> <td class="tdc">8.96</td>
+      <td class="tdc">9.21</td> <td class="tdc">9.46</td>
+      <td class="tdc">9.72</td> <td class="tdc">9.97</td>
+   </tr><tr>
+      <td class="tdc">4.8</td> <td class="tdc">7.47</td>
+      <td class="tdc">7.72</td> <td class="tdc">7.97</td>
+      <td class="tdc">8.22</td> <td class="tdc">8.47</td>
+      <td class="tdc">8.72</td> <td class="tdc">8.98</td>
+      <td class="tdc">9.23</td> <td class="tdc">9.48</td>
+      <td class="tdc">9.74</td> <td class="tdc">9.99</td>
+   </tr><tr>
+      <td class="tdc bb">4.9</td> <td class="tdc bb">7.49</td>
+      <td class="tdc bb">7.74</td> <td class="tdc bb">7.99</td>
+      <td class="tdc bb">8.24</td> <td class="tdc bb">8.49</td>
+      <td class="tdc bb">8.74</td> <td class="tdc bb">9.00</td>
+      <td class="tdc bb">9.25</td> <td class="tdc bb">9.50</td>
+      <td class="tdc bb">9.76</td> <td class="tdc bb">10.01&#8199;</td>
+   </tr><tr>
+      <td class="tdc">5.0</td> <td class="tdc">7.51</td>
+      <td class="tdc">7.76</td> <td class="tdc">8.01</td>
+      <td class="tdc">8.26</td> <td class="tdc">8.51</td>
+      <td class="tdc">8.76</td> <td class="tdc">9.02</td>
+      <td class="tdc">9.27</td> <td class="tdc">9.52</td>
+      <td class="tdc">9.78</td> <td class="tdc">10.03&#8199;</td>
+   </tr><tr>
+      <td class="tdc">5.1</td> <td class="tdc">7.53</td>
+      <td class="tdc">7.78</td> <td class="tdc">8.03</td>
+      <td class="tdc">8.28</td> <td class="tdc">8.53</td>
+      <td class="tdc">8.79</td> <td class="tdc">9.04</td>
+      <td class="tdc">9.29</td> <td class="tdc">9.54</td>
+      <td class="tdc">9.80</td> <td class="tdc">10.05&#8199;</td>
+   </tr><tr>
+      <td class="tdc">5.2</td> <td class="tdc">7.55</td>
+      <td class="tdc">7.80</td> <td class="tdc">8.05</td>
+      <td class="tdc">8.30</td> <td class="tdc">8.55</td>
+      <td class="tdc">8.81</td> <td class="tdc">9.06</td>
+      <td class="tdc">9.31</td> <td class="tdc">9.56</td>
+      <td class="tdc">9.82</td> <td class="tdc">10.07&#8199;</td>
+   </tr><tr>
+      <td class="tdc">5.3</td> <td class="tdc">7.57</td>
+      <td class="tdc">7.82</td> <td class="tdc">8.07</td>
+      <td class="tdc">8.32</td> <td class="tdc">8.57</td>
+      <td class="tdc">8.83</td> <td class="tdc">9.08</td>
+      <td class="tdc">9.33</td> <td class="tdc">9.58</td>
+      <td class="tdc">9.84</td> <td class="tdc">10.09&#8199;</td>
+   </tr><tr>
+      <td class="tdc">5.4</td> <td class="tdc">7.59</td>
+      <td class="tdc">7.84</td> <td class="tdc">8.09</td>
+      <td class="tdc">8.34</td> <td class="tdc">8.60</td>
+      <td class="tdc">8.85</td> <td class="tdc">9.10</td>
+      <td class="tdc">9.36</td> <td class="tdc">9.61</td>
+      <td class="tdc">9.86</td> <td class="tdc">10.11&#8199;</td>
+   </tr><tr>
+      <td class="tdc">5.5</td> <td class="tdc">7.61</td>
+      <td class="tdc">7.86</td> <td class="tdc">8.11</td>
+      <td class="tdc">8.36</td> <td class="tdc">8.62</td>
+      <td class="tdc">8.87</td> <td class="tdc">9.12</td>
+      <td class="tdc">9.38</td> <td class="tdc">9.63</td>
+      <td class="tdc">9.88</td> <td class="tdc">10.13&#8199;</td>
+   </tr><tr>
+      <td class="tdc">5.6</td> <td class="tdc">7.63</td>
+      <td class="tdc">7.88</td> <td class="tdc">8.13</td>
+      <td class="tdc">8.39</td> <td class="tdc">8.64</td>
+      <td class="tdc">8.89</td> <td class="tdc">9.15</td>
+      <td class="tdc">9.40</td> <td class="tdc">9.65</td>
+      <td class="tdc">9.90</td> <td class="tdc">10.15&#8199;</td>
+   </tr><tr>
+      <td class="tdc">5.7</td> <td class="tdc">7.65</td>
+      <td class="tdc">7.90</td> <td class="tdc">8.15</td>
+      <td class="tdc">8.41</td> <td class="tdc">8.66</td>
+      <td class="tdc">8.91</td> <td class="tdc">9.17</td>
+      <td class="tdc">9.42</td> <td class="tdc">9.67</td>
+      <td class="tdc">9.92</td> <td class="tdc">10.17&#8199;</td>
+   </tr><tr>
+      <td class="tdc">5.8</td> <td class="tdc">7.67</td>
+      <td class="tdc">7.92</td> <td class="tdc">8.17</td>
+      <td class="tdc">8.43</td> <td class="tdc">8.68</td>
+      <td class="tdc">8.94</td> <td class="tdc">9.19</td>
+      <td class="tdc">9.44</td> <td class="tdc">9.69</td>
+      <td class="tdc">9.94</td> <td class="tdc">10.19&#8199;</td>
+   </tr><tr>
+      <td class="tdc">5.9</td> <td class="tdc">7.69</td>
+      <td class="tdc">7.94</td> <td class="tdc">8.20</td>
+      <td class="tdc">8.45</td> <td class="tdc">8.70</td>
+      <td class="tdc">8.96</td> <td class="tdc">9.21</td>
+      <td class="tdc">9.46</td> <td class="tdc">9.71</td>
+      <td class="tdc">9.96</td> <td class="tdc">10.22&#8199;</td>
+   </tr><tr>
+      <td class="tdc bb">6.0</td> <td class="tdc bb">7.71</td>
+      <td class="tdc bb">7.96</td> <td class="tdc bb">8.22</td>
+      <td class="tdc bb">8.47</td> <td class="tdc bb">8.72</td>
+      <td class="tdc bb">8.98</td> <td class="tdc bb">9.23</td>
+      <td class="tdc bb">9.48</td> <td class="tdc bb">9.73</td>
+      <td class="tdc bb">9.98</td> <td class="tdc bb">10.24&#8199;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_482"></a>[Pg 482]</span>
+<b>449. Determination of Ash.</b>—In the determination of the solid
+residue obtained by drying milk, it is important to observe the
+directions already given (<b><a href="#P_28">28-32</a></b>).</p>
+
+<p>In the direct ignition of the sample, a portion of the sulfur and
+phosphorus may escape oxidation and be lost as volatile compounds.
+This loss may be avoided by the use of proper oxidizing agents or by
+conducting the combustion as heretofore described.<a id="FNanchor_430" href="#Footnote_430" class="fnanchor">[430]</a>
+In the official method, it is directed to add six cubic centimeters
+of nitric acid to twenty of milk, evaporate to dryness and ignite the
+residue at a low red heat until free of carbon.<a id="FNanchor_431" href="#Footnote_431" class="fnanchor">[431]</a>
+It is doubtful if this precaution be entirely sufficient to save all
+the sulfur and phosphorus, but the method is evidently more reliable
+than the common one of direct ignition without any oxidizing reagent
+whatever.</p>
+
+<h3>ESTIMATION OF FAT.</h3>
+
+<p><b>450. Form of Fat in Milk.</b>—The fat in milk occurs in the form
+of globules suspended in the liquid, in other words in the form of an
+emulsion. Many authorities have asserted that each globule of fat is
+contained in a haptogenic membrane composed presumably of nitrogenous
+matter, but there is no convincing evidence of the truth of this
+opinion. The weight of experimental evidence is in the opposite
+direction. The supposed action of the membrane and the phenomena
+produced thereby are more easily explained by the surface tension
+existing between the fat globules and the menstruum in which they are
+suspended.</p>
+
+<p>Babcock affirms that the spontaneous coagulation of the fibrin present
+in milk tends to draw the fat globules into clusters, and this tendency
+can be arrested by adding a little soda or potash lye to the milk as
+soon as it is drawn.<a id="FNanchor_432" href="#Footnote_432" class="fnanchor">[432]</a></p>
+
+<p>The diameter of the fat globules is extremely variable, extending in
+some cases from two to twenty micromillimeters. In cow milk, the usual
+diameters are from three to five micromillimeters.</p>
+
+<p><b>451. Number of Fat Globules in Milk.</b>—The number of fat globules
+<span class="pagenum"><a id="Page_483"></a>[Pg 483]</span>
+in milk depends on their size and the percentage of fat. It is evident
+that no definite statement of the number can be made. There is a
+tendency, on the part of the globules, to diminish in size and increase
+in number as the period of lactation is prolonged. To avoid large
+numbers, it is convenient to give the number of globules in 0.0001
+cubic millimeter. This number may be found within wide limits depending
+on the individual, race, food and other local conditions to which the
+animal or herd is subjected. In general, in whole milk this number will
+be found between 140 and 250.</p>
+
+<p><b>452. Method of Counting Globules.</b>—The number of globules in
+milk is computed with the aid of the microscope. The most convenient
+method is the one devised by Babcock.<a id="FNanchor_433" href="#Footnote_433" class="fnanchor">[433]</a>
+In carrying out this
+computation, capillary tubes, from two to three centimeters long and
+about one-tenth millimeter in internal diameter, are provided. The
+exact diameter of each tube, in at least three points, is determined
+by the micrometer attachment of the microscope, and from these
+measurements the mean diameter of the tube is calculated. This known,
+its cubic content for any given length is easily computed. Ten cubic
+centimeters of the milk are diluted with distilled water to half a
+liter and one end of a capillary tube dipped therein. The tube is
+quickly filled with diluted milk and each end is closed with a little
+wax to prevent evaporation. Several of these tubes being thus prepared,
+they are placed in a horizontal position on the stage of the microscope
+and covered with glycerol and a cover glass. The tubes are left at
+rest for some time until all the fat globules have attached themselves
+to the upper surfaces, in which position they are easily counted.
+The micrometer is so placed as to lie parallel with the tubes, and
+the number of globules, corresponding to each division of its scale,
+counted. The mean number of globules corresponding to each division of
+the micrometer scale is thus determined.</p>
+
+<p>To compare the data obtained with each tube they are reduced to a
+common basis of the number of globules found in a length of fifty
+divisions of the micrometer scale in a tube having a diameter of 100
+divisions, using the formula</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>N</i> = &nbsp;</td>
+      <td class="tdc bb">10000<i>n</i></td>
+   </tr><tr>
+      <td class="tdc"><i>d</i>²</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_484"></a>[Pg 484]</span>
+in which <i>n</i> = the number of globules found in the standard
+length of tube measured and <i>d</i> = the diameter of the tube. It
+is not difficult to actually count all the globules in a length of
+fifty divisions of the scale, but the computation may also be made
+from the mean numbers found in a few divisions. The usual number of
+globules found in a length of 0.1 millimeter in a tube 0.1 millimeter
+in diameter, varies from fifty to one hundred.</p>
+
+<div class="blockquot">
+<p><i>Example.</i>—The length of one division of the micrometer scale is
+0.002 millimeter, and the internal diameter of the tube 0.1 millimeter.
+The content of a tube, of a length of 0.002 × 50 = 0.1 millimeter, is
+therefore 0.0007854 cubic millimeter.</p>
+
+<p>The cubic content of a tube 100 scale divisions in diameter and fifty
+in length is 0.0031416 cubic millimeter. The number of globules found
+in fifty divisions of the tubes used is 40. Then the number which would
+be contained in a tube of a diameter of 100 divisions of the micrometer
+scale and a length of fifty divisions thereof is</p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>N</i> = &nbsp;</td>
+      <td class="tdc bb">10000<i>n</i></td>
+      <td class="tdl" rowspan="2">&nbsp; = &nbsp;</td>
+      <td class="tdc bb">400000</td>
+      <td class="tdl" rowspan="2">&nbsp; = 160.</td>
+   </tr><tr>
+      <td class="tdc"><i>d</i>²</td>
+      <td class="tdc">2500</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Since the milk is diluted fifty times, the actual number of globules
+corresponding to the volume given is 8000. It is convenient to reduce
+the observations to some definite volume, <i>exempla gratia</i>, 0.0001
+cubic centimeter. The equation for this in the above instance is
+0.0031416: 0.0001 = 8000: <i>x</i>, whence <i>x</i> = 223, = number
+of fat globules in 0.0001 cubic millimeter.</p>
+</div>
+
+<p>In one cubic millimeter of milk there are therefore 2,230,000 fat
+globules, and in one cubic centimeter 2,230,000,000 globules. In a
+single drop of milk there are from one to two hundred million fat
+globules.<a id="FNanchor_434" href="#Footnote_434" class="fnanchor">[434]</a></p>
+
+<p><b>453. Classification of Methods of Determining Fat in Milk.</b>—The
+fat, being the most valuable of the constituents of milk, is the
+subject of a number of analytical processes. An effort will be made
+here to classify these various methods and to illustrate each class
+with one or more typical processes. In general the methods may be
+divided into analytical and commercial, those of the first class being
+used for scientific and of the other for trade purposes. For normal
+milk, some of the trade methods have proved to be quite as accurate as
+<span class="pagenum"><a id="Page_485"></a>[Pg 485]</span>
+the more chronokleptic analytical processes to which, in disputed
+cases, a final appeal must be taken. When the analyst is called upon to
+determine the fat in a large number of samples of milk some one of the
+trade methods may often be adopted with great advantage.</p>
+
+<p><b>454. Dry Extraction Methods.</b>—Among the oldest and most reliable
+methods of determining fat in milk, are included those processes based
+on the principle of drying the milk and extracting the fat from the
+residue by an appropriate solvent. The solvents generally employed are
+ether and petroleum spirit of low boiling point. The methods of drying
+are legion.</p>
+
+<p>In extracting with ether, it must not be forgotten that other bodies
+than fat may pass into solution on the one hand and on the other any
+substituted glycerid, such as lecithin or nuclein, which may be present
+may escape solution, at least in part. Perhaps petroleum spirit,
+boiling at from 45° to 60°, is the best solvent for fat, but it is
+almost the universal custom in this and other countries to use ether.</p>
+
+<p id="P_455"><b>455. The Official Methods.</b>—In the methods adopted by the
+Association of Official Agricultural Chemists two processes are
+recommended.</p>
+
+<p>(1) <i>The Asbestos Process</i>: In this process it is directed to
+extract the residue from the determination of water by the asbestos
+method (<b><a href="#P_447">447</a></b>) with anhydrous pure ether until the fat is removed,
+evaporate the ether, dry the fat at 100° and weigh. The fat may also be
+determined by difference, after drying the extracted cylinders at 100°.</p>
+
+<p>(2) <i>Paper Coil Method</i>: This is essentially the method proposed
+by Adams as modified by the author.<a id="FNanchor_435" href="#Footnote_435" class="fnanchor">[435]</a>
+Coils made of thick filter paper are cut into strips 6.25 by 62.5
+centimeters, thoroughly extracted with ether and alcohol, or the weight
+of the extract corrected by a constant obtained for the paper. If this
+latter method be used, a small amount of anhydrous sodium carbonate
+should be added. Paper free of matters soluble in ether is also to be
+had for this purpose. From a weighing bottle about five grams of milk
+are transferred to the coil by a pipette, taking care to keep dry the
+<span class="pagenum"><a id="Page_486"></a>[Pg 486]</span>
+lower end of the coil. The coil, dry end down, is placed on a piece
+of glass, and dried at a temperature of boiling water for one hour,
+or better, dried in hydrogen at a temperature of boiling water,
+transferred to an extraction apparatus and extracted with absolute
+ether or petroleum spirit boiling at about 45°. The extracted fat is
+dried in hydrogen and weighed. Experience has shown that drying in
+hydrogen is not necessary. The fat may be conveniently dried in partial vacuo.</p>
+
+<p><b>456. Variations of Extraction Method.</b>—The method of preparing
+the milk for fat extraction is capable of many variations. Some of the
+most important follow:</p>
+
+<p>(1) <i>Evaporation on Sand</i>: The sand should be pure, dry and of
+uniform size of grain. It may be held in a dish or tube. The dish may
+be made of tin foil, so that it can be introduced with its contents
+into the extraction apparatus after the desiccation is complete. For
+this purpose, it is cut into fragments of convenient size after its
+contents have been poured into the extractor. The scissors used are
+washed with the solvent.</p>
+
+<p>(2) <i>Evaporation on Kieselguhr</i>: Dry kieselguhr (infusorial
+earth, tripoli) may take the place of the sand as above noted. The
+manipulation is the same as with sand.</p>
+
+<p>(3) <i>Evaporation on Plaster of Paris</i>,<a id="FNanchor_436" href="#Footnote_436" class="fnanchor">[436]</a>
+(<i>Soxhlet Method</i>),<a id="FNanchor_437" href="#Footnote_437" class="fnanchor">[437]</a>
+(4) <i>On Pumice Stone</i>, (5) <i>On Powdered Glass</i>, (6) <i>On
+Chrysolite</i>:<a id="FNanchor_438" href="#Footnote_438" class="fnanchor">[438]</a>
+The manipulation in these cases is conducted as with sand and no
+detailed description is required.</p>
+
+<p>(7) <i>Evaporation on Organic Substances</i>: These variations would
+fall under the general heading of drying on paper. The following
+materials have been used; <i>viz.</i>, sponge,<a id="FNanchor_439" href="#Footnote_439" class="fnanchor">[439]</a>
+lint,<a id="FNanchor_440" href="#Footnote_440" class="fnanchor">[440]</a>
+and wood pulp.<a id="FNanchor_441" href="#Footnote_441" class="fnanchor">[441]</a>
+In these variations the principal precautions to be observed are to
+secure the organic material in a dry state and free of any matter
+soluble in the solvent used.</p>
+
+<p>(8) <i>Dehydration with Anhydrous Copper Sulfate</i>: In this process
+the water of the sample is absorbed by powdered anhydrous copper
+sulfate, the residual mass extracted and the butter fat obtained
+determined by saponification and titration.<a id="FNanchor_442" href="#Footnote_442" class="fnanchor">[442]</a>
+In the manipulation about twenty grams of the anhydrous copper sulfate
+<span class="pagenum"><a id="Page_487"></a>[Pg 487]</span>
+are placed in a mortar, a depression made therein in such a manner that
+ten cubic centimeters of milk can be poured into it without wetting
+it through to the mortar. The water is soon absorbed when the mass is
+ground with a little dry sand and transferred to the extractor.</p>
+
+<p>Petroleum spirit of low boiling point is used as a solvent, successive
+portions of about fifteen cubic centimeters each being forced through
+the powdered mass under pressure. Two or three treatments with the
+petroleum are required. The residual butter fat, after the evaporation
+of the petroleum, is saponified with a measured portion, about
+twenty-five cubic centimeters, of seminormal alcoholic potash lye. The
+residual alkali is determined by titration with seminormal hydrochloric
+acid in the usual manner. From the data obtained is calculated the
+quantity of alkali employed in the saponification. The weight of butter
+fat extracted is then calculated on the assumption that 230 milligrams
+of potash are required to saponify one gram of the fat.</p>
+
+<p><b>457. Gypsum Method for Sour Milk.</b>—In sour milk, extraction
+of the dry residue with ether is attended with danger of securing a
+part of the free lactic acid in the extract. This may be avoided, at
+least in part, by making the milk neutral or slightly alkaline before
+desiccation. This method is illustrated by a variation of Soxhlet’s
+method of drying on gypsum proposed by Kühn.<a id="FNanchor_443" href="#Footnote_443" class="fnanchor">[443]</a>
+The curdled milk is treated with potash lye of forty per cent strength
+until the reaction is slightly alkaline. For absorbing the sample
+before drying, a mixture is employed consisting of twenty-five grams
+of plaster of paris, four of precipitated carbonate of lime and two
+of acid potassium sulfate. To this mixture ten grams of the milk,
+rendered alkaline as above noted, are added in a desiccating dish, the
+excess of moisture evaporated at 100°, the residual mass finely ground
+and extracted with ether for four hours. A little gypsum may be found
+in the solution, but in such small quantities as not to interfere
+seriously with the accuracy of the results obtained.</p>
+
+<p><b>458. Estimation of Fat in Altered Milk.</b>—In altered milk the
+lactose has usually undergone a fermentation affording considerable
+quantities of lactic acid. If such milks be treated by the extraction
+method for fat, the results will always be too high, because of the
+solubility of lactic acid in ether.
+<span class="pagenum"><a id="Page_488"></a>[Pg 488]</span></p>
+
+<p>Vizern<a id="FNanchor_444" href="#Footnote_444" class="fnanchor">[444]</a>
+has proposed to avoid this error by first warming the soured
+milk for a few minutes to 40°, at which temperature the clabber is
+easily divided by vigorous shaking. Of the milk thus prepared, thirty
+grams are diluted with two or three volumes of water and poured onto a
+smooth and moistened filter. The vessel and filter are washed several
+times until the filtrate presents no further acid reaction. The filter
+and its contents are next placed in a vessel containing some fine
+washed sand. A small quantity of water is added, sufficient to form a
+paste. With a stirring rod, the filter is entirely broken up and the
+whole mass thoroughly mixed. Dried on the water bath the material is
+subjected to extraction in the ordinary way. Several analyses made
+on fresh milk and on milk kept for several months show that almost
+identical results are obtained.</p>
+
+<p>In respect of this process there would be danger, on long standing,
+of the formation of free acids from butter glycerids, and these acids
+would be removed by the process of washing prescribed. In this case the
+quantity of fat obtained would be less than in the original sample.</p>
+
+<p><b>459. Comparison of Methods.</b>—An immense amount of work has been
+done by analysts in comparing the various types of extraction methods
+outlined above.<a id="FNanchor_445" href="#Footnote_445" class="fnanchor">[445]</a></p>
+
+<p>The consensus of opinion is that good results are obtained by all the
+methods when properly conducted, and preference is given to the two
+methods finally adopted by the Association of Official Chemists. As
+solvents, pure ether and petroleum spirit of low boiling point are
+preferred. The direct extraction gravimetric processes are important,
+since it is to these that all the other quicker and easier methods must
+appeal for the proof of their accuracy.</p>
+
+<p><b>460. Wet Extraction Methods.</b>—It has been found quite
+impracticable to extract the fat from milk by shaking it directly with
+the solvent. An emulsion is produced whereby the solvent itself becomes
+incorporated with the other constituents of the milk, and from which it
+is not separated easily even with the aid of whirling. The disturbing
+element which prevents the separation of the solvent is doubtless the
+<span class="pagenum"><a id="Page_489"></a>[Pg 489]</span>
+colloid casein, since, when this is previously rendered soluble, the
+separation of the solvent holding the fat is easily accomplished.</p>
+
+<p>The principle on which the methods of wet extraction are based is a
+simple one; <i>viz.</i>, to secure a complete or partial solution
+of the casein and subsequently to extract the fat with a solvent
+immiscible with water. The methods may be divided into three great
+classes; <i>viz.</i>, (1) those in which the solvent is evaporated from
+the whole of the extracted fat and the residual matters weighed; (2)
+processes in which an aliquot part of the fat solution is employed and
+the total fat calculated from the data secured; (3) the density of the
+fat solution is determined at a definite temperature and the percentage
+of fat corresponding thereto determined from tables or otherwise.
+Methods (1) and (2) are practically identical in principle and one
+or the other may be applied according to convenience or to local
+considerations. The methods may be further subdivided in respect of the
+reagents used to secure complete or partial solution of the casein, as,
+for instance, alkali or acid.<a id="FNanchor_446" href="#Footnote_446" class="fnanchor">[446]</a></p>
+
+<p><b>461. Solution in an Acid.</b>—A good type of these processes is the
+method of Schmid.<a id="FNanchor_447" href="#Footnote_447" class="fnanchor">[447]</a>
+In this process ten cubic centimeters of milk are placed in a test
+tube of about five times that content, graduated to measure small
+volumes. An equal quantity of hydrochloric acid is added, the mixture
+shaken, boiled until it turns dark brown, and cooled quickly. The
+fat is extracted by shaking with thirty cubic centimeters of ether.
+After standing some time the ethereal solution separates and its
+volume is noted. An aliquot part of the solution is removed, the
+solvent evaporated, and the weight of fat in the whole determined by
+calculation.</p>
+
+<p>The schmid process has been improved by Stokes,<a id="FNanchor_448" href="#Footnote_448" class="fnanchor">[448]</a>
+Hill,<a id="FNanchor_449" href="#Footnote_449" class="fnanchor">[449]</a>
+and Richmond.<a id="FNanchor_450" href="#Footnote_450" class="fnanchor">[450]</a>
+The most important of these variations consists in weighing instead of
+measuring the milk employed, thus insuring greater accuracy. Dyer and
+Roberts affirm that the ether dissolves some of the caramel products
+formed on boiling condensed milk with hydrochloric acid, and that the
+data obtained in such cases by the process of Schmid are too high.<a id="FNanchor_451" href="#Footnote_451" class="fnanchor">[451]</a></p>
+
+<p>Since lactic acid is also slightly soluble in ether, sour milk should
+not be extracted with that solvent. In these cases petroleum spirit, or
+<span class="pagenum"><a id="Page_490"></a>[Pg 490]</span>
+a mixture of petroleum and ether, as suggested by Pinette, may be
+used.<a id="FNanchor_452" href="#Footnote_452" class="fnanchor">[452]</a>
+Another variation consists in extracting the fat with several portions
+of the solvent and evaporating all the extracts thus obtained to get
+the total fat. This method is perhaps the best of those in which the
+fat is extracted from the residual liquid after the decomposition of
+the casein by an acid, and may be recommended as both reliable and
+typical within the limitations mentioned above.</p>
+
+<p><b>462. Solution in an Alkali.</b>—The casein of milk is not so
+readily dissolved in an alkali as in an acid, but the solution is
+sufficient to permit the extraction of the fat. Soda and potash lyes
+and ammonia are the alkaline bodies usually employed. To promote the
+separation of the emulsions, alcohol is added with advantage. The
+principle of the process rests on the observed power of an alkali
+to free the fat globules sufficiently to allow them to dissolve in
+ether or some other solvent. When the solvent has separated from the
+emulsion at first formed, the whole or a part of it is used for the
+determination of fat in a manner entirely analogous to that employed
+in the process with the acid solutions described above. There are many
+methods based on this principle, and some of the typical ones will be
+given below. Experience has shown that extraction from an alkaline
+solution is more troublesome and less perfect than from an acid and
+these alkaline methods are, therefore, not so much practiced now as
+they were formerly.</p>
+
+<p><b>463. Method of Short.</b>—Instead of measuring the volume of the
+separated fat, Short has proposed a method in which the casein is
+dissolved in an alkali and the fat at the same time saponified. The
+soap thus produced is decomposed by sulfuric acid and the volume of the
+separated fat acids noted. This volume represents eighty-seven per cent
+of the corresponding volume of fat.<a id="FNanchor_453" href="#Footnote_453" class="fnanchor">[453]</a></p>
+
+<p>The solvent employed is a mixture of sodium and potassium hydroxids,
+containing in one liter 125 and 150 grams, respectively, of these
+alkalies. The sample of milk is mixed with half its volume of the
+reagent and placed in boiling water for two hours. By this treatment
+<span class="pagenum"><a id="Page_491"></a>[Pg 491]</span>
+the casein is dissolved and the fat saponified. After cooling to about
+60°, the soap is decomposed by the addition of equal parts of sulfuric
+and acetic acids. The tubes containing the mixture are again placed in
+boiling water for an hour and they are then filled with boiling water
+to within one inch of the top. The tubes may either be furnished with a
+graduation or the column of fat be measured by a scale.</p>
+
+<p><b>464. Method of Thörner.</b>—The process of Short is conducted by
+Thörner as follows:<a id="FNanchor_454" href="#Footnote_454" class="fnanchor">[454]</a></p>
+
+<p>Ten cubic centimeters of milk measured at 15° are saponified, in
+tubes fitting a centrifugal, by the addition of one and a half cubic
+centimeters of an alcoholic potash lye, containing 160 grams of
+potassium hydroxid per liter, or one cubic centimeter of an aqueous
+fifty per cent soda lye. The saponification is hastened by setting the
+tubes in boiling water, where they remain for two minutes. The soap
+formed is decomposed with a strong acid, sulfuric preferred, the tubes
+placed in the centrifugal and whirled for four minutes, when the fat
+acids will be formed in the narrow graduated part of the tube and the
+volume occupied thereby is noted after immersion in boiling water.
+Thörner’s process is not followed in this country, but is used to a
+considerable extent in Germany.<a id="FNanchor_455" href="#Footnote_455" class="fnanchor">[455]</a></p>
+
+<p><b>465. Liebermann’s Method.</b>—In this method, fifty cubic
+centimeters of milk, at ordinary temperatures, are placed in a glass
+cylinder twenty-five centimeters high and about four and a half
+internal diameter; five cubic centimeters of potash lye of 1.27
+specific gravity are added, the cylinder closed with a well fitting
+cork stopper and thoroughly shaken.<a id="FNanchor_456" href="#Footnote_456" class="fnanchor">[456]</a>
+After shaking, fifty cubic centimeters of petroleum spirit, boiling
+point about 60°, are added. The cylinder is again stoppered and
+vigorously shaken until an emulsion is formed. To this emulsion fifty
+cubic centimeters of alcohol of ninety-five per cent strength are
+added, and the whole again thoroughly shaken. After four or five
+minutes the petroleum spirit, containing the fat, separates. In order
+to insure an absolute separation of the fat, however, the shaking may
+be repeated three or four times for about one-quarter minute, waiting
+each time between the shakings until the spirit separates.
+<span class="pagenum"><a id="Page_492"></a>[Pg 492]</span></p>
+
+<p>Of the separated petroleum spirit twenty cubic centimeters are placed
+in a small weighed flask. The use of the flask is recommended on
+account of the ease with which the petroleum spirit can be evaporated
+without danger of loss of fat. Instead of the flask a weighed beaker or
+other weighed dish may be employed.</p>
+
+<p>The petroleum spirit is carefully evaporated on a water-bath and the
+residue dried at 110° to 120° for one hour. The weight found multiplied
+by five gives the content of fat in 100 cubic centimeters of the
+milk. The percentage by weight can then be calculated by taking into
+consideration the specific gravity of the milk employed.</p>
+
+<p>The results obtained by this method agree well with those obtained by
+the paper coil method, when petroleum spirit instead of sulfuric ether
+is used as the solvent for the fat. Sulfuric ether, however, gives
+an apparently higher content of fat because of the solution of other
+bodies not fat present in the milk.</p>
+
+<p><b>466. Densimetric Methods.</b>—Instead of evaporating the separated
+fat solution and weighing the residue, its density may be determined
+and the percentage of fat dissolved therein obtained by calculation,
+or more conveniently from tables. The typical method of this kind is
+due to Soxhlet, and until the introduction of modern rapid volumetric
+processes, it was used perhaps more extensively than any other
+proceeding for the determination of fat in milk.<a id="FNanchor_457" href="#Footnote_457" class="fnanchor">[457]</a>
+The reagents employed in the process are ether saturated with water and
+a potash lye containing 400 grams of potash in a liter. The principle
+of the process is based on the assumption that a milk made alkaline
+with potash will give up all its fat when shaken with ether and the
+quantity of fat in solution can be determined by ascertaining the
+specific gravity of the ethereal solution.
+<span class="pagenum"><a id="Page_493"></a>[Pg 493]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_108" src="images/fig108.jpg" alt="" width="400" height="514" >
+    <p class="center spb1">Fig. 108. Areometric Fat Apparatus.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_494"></a>[Pg 494]</span>
+The apparatus is arranged as shown in <a href="#FIG_108">Fig. 108</a>,
+whereby it is easy to drive the ethereal fat solution into the
+measuring vessel by means of the bellows shown. In the bottle, seen
+at the right of the engraving are placed 200 cubic centimeters of
+milk, ten of the potash lye and sixty of the aqueous ether. The milk
+and potash are first added and well shaken, the ether then added, and
+the contents of the bottle are shaken until a homogeneous emulsion
+is formed. The bottle is then set aside for the separation of the
+ethereal solution, which is promoted by gently jarring it from time to
+time. When the chief part of the solution has separated, a sufficient
+quantity of it is driven over into the measuring apparatus, by means
+of the air bulbs, to float the hydrometer contained in the inner
+cylinder. After a few moments the scale of the oleometer is read and
+the percentage of fat calculated from the table. All the measurements
+are made at a temperature of 17°.5. The temperature is preserved
+constant by filling the outer cylinder of the apparatus with water.
+If the room be warmer than 17°.5, the water added should be at a
+temperature slightly below that and <i>vice versa</i>. The oleometer
+carries a thermometer which indicates the moment when the reading is to
+be made.</p>
+
+<p>The scale of the oleometer is graduated arbitrarily from 43 to 66,
+corresponding to the specific gravities 0.743 and 0.766, respectively,
+or to corresponding fat contents of 2.07 and 5.12 per cent, in the
+milk, a range which covers most normal milks.</p>
+
+<p>In the use of the table the per cents corresponding to parts of an
+oleometer division can be easily calculated.</p>
+
+<p class="f120 spa1"><b><span class="smcap">Table for Calculating
+Per Cent of Fat in Milk<br>by Areometric Method of Soxhlet.</span></b></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb">Reading of &nbsp;<br>oleometer.</th>
+      <th class="tdc bb">&nbsp; Per cent fat &nbsp; <br>in milk.</th>
+      <th class="tdc bb">Reading of &nbsp;<br>oleometer.</th>
+      <th class="tdc bb">&nbsp; Per cent fat &nbsp; <br>in milk.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">43</td>
+      <td class="tdc">2.07</td>
+      <td class="tdc">55</td>
+      <td class="tdc">3.49</td>
+   </tr><tr>
+      <td class="tdc">44</td>
+      <td class="tdc">2.18</td>
+      <td class="tdc">56</td>
+      <td class="tdc">3.63</td>
+   </tr><tr>
+      <td class="tdc">45</td>
+      <td class="tdc">2.30</td>
+      <td class="tdc">57</td>
+      <td class="tdc">3.75</td>
+   </tr><tr>
+      <td class="tdc">46</td>
+      <td class="tdc">2.40</td>
+      <td class="tdc">58</td>
+      <td class="tdc">3.90</td>
+   </tr><tr>
+      <td class="tdc">47</td>
+      <td class="tdc">2.52</td>
+      <td class="tdc">59</td>
+      <td class="tdc">4.03</td>
+   </tr><tr>
+      <td class="tdc">48</td>
+      <td class="tdc">2.64</td>
+      <td class="tdc">60</td>
+      <td class="tdc">4.18</td>
+   </tr><tr>
+      <td class="tdc">49</td>
+      <td class="tdc">2.76</td>
+      <td class="tdc">61</td>
+      <td class="tdc">4.32</td>
+   </tr><tr>
+      <td class="tdc">50</td>
+      <td class="tdc">2.88</td>
+      <td class="tdc">62</td>
+      <td class="tdc">4.47</td>
+   </tr><tr>
+      <td class="tdc">51</td>
+      <td class="tdc">3.00</td>
+      <td class="tdc">63</td>
+      <td class="tdc">4.63</td>
+   </tr><tr>
+      <td class="tdc">52</td>
+      <td class="tdc">3.12</td>
+      <td class="tdc">64</td>
+      <td class="tdc">4.79</td>
+   </tr><tr>
+      <td class="tdc">53</td>
+      <td class="tdc">3.25</td>
+      <td class="tdc">65</td>
+      <td class="tdc">4.95</td>
+   </tr><tr>
+      <td class="tdc">54</td>
+      <td class="tdc">3.37</td>
+      <td class="tdc">66</td>
+      <td class="tdc">5.12</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>467. Application of the Areometric Method.</b>—Soxhlet’s method, as
+outlined above, with many modifications, has been extensively used in
+<span class="pagenum"><a id="Page_495"></a>[Pg 495]</span>
+Europe and to a limited degree in this country, and the results
+obtained are in general satisfactory, when the sample is a mixed one
+from a large number of cows and of average composition.</p>
+
+<p>The author has shown that the process is not applicable to abnormal
+milk and often not to milk derived from one animal alone.<a id="FNanchor_458" href="#Footnote_458" class="fnanchor">[458]</a></p>
+
+<p>The chief difficulty is found in securing a separation of the emulsion.
+This trouble can usually be readily overcome by whirling. Any
+centrifugal machine, which can receive the bottle in which the emulsion
+is made, may be employed for that purpose.</p>
+
+<p>Since the introduction of more modern and convenient methods of fat
+determination, the areometric method has fallen into disuse and perhaps
+is no longer practiced in this country. It is valuable now chiefly from
+the fact that many of the recorded analyses of milk fat were made by
+it, and also for its typical character in representing all methods of
+analysis of fat in milk based on the density of ethereal solutions.</p>
+
+<p><b>468. The Lactobutyrometer.</b>—A typical instrument for measuring
+the volume of fat in a milk is known as Marchand’s lactobutyrometer.
+It is based on the observation that ether will dissolve the fat from
+milk when the casein is wholly or partly dissolved by an alkali, and
+further, that the fat in an impure form can be separated from its
+ethereal solution by the action of alcohol. Experience has shown
+that all the fat is not separated from the ethereal solution by this
+process, and also that the part separated is a saturated solution in
+ether. The method cannot be rigorously placed in the two classes given
+above, but being volumetric demands consideration here chiefly because
+of its historical interest.<a id="FNanchor_459" href="#Footnote_459" class="fnanchor">[459]</a></p>
+
+<p>The instrument employed by Marchand is a tube about thirty centimeters
+long and twelve in diameter, closed at one end and marked in three
+portions of ten cubic centimeters each. The upper part is divided in
+tenths of a cubic centimeter. The superior divisions are subdivided so
+that the readings can be made to hundredths of a cubic centimeter.</p>
+
+<p>The tube is filled with milk to the first mark and two or three drops of
+<span class="pagenum"><a id="Page_496"></a>[Pg 496]</span>
+a twenty-five per cent solution of soda lye added thereto. Ether is
+poured in to the second mark, the tube closed and vigorously shaken.
+Alcohol of about ninety per cent strength is added to the upper mark,
+the tube closed, shaken and allowed to stand in a vertical position,
+with occasional jolting, until the separation of the liquids is
+complete. In order to promote the separation the tube is placed in a
+cylinder containing water at 40°.</p>
+
+<p>When the separation is complete the milk serum is found at the bottom,
+the mixture of alcohol and ether in the middle and the fat at the top.
+The mixture of ether and alcohol contains 0.126 gram of fat, and each
+cubic centimeter of the separated ether fat 0.233 gram of fat. The
+total volume of the separated fat, multiplied by 0.233, and the product
+increased by 0.126, will give the weight of fat in the ten cubic
+centimeters of milk employed.</p>
+
+<p class="blockquot"><i>Example.</i>—Milk used, ten cubic centimeters
+of 1.032 specific gravity = 10.32 grams. The observed volume of the
+saturated ether fat solution is two cubic centimeters. Then the weight
+of fat is 2 × 0.233 + 0.126 = 0.592 gram. The percentage of fat in the
+sample is 0.592 × 100 ÷ 10.32 = 5.74.</p>
+
+<p>In the apparatus used in this laboratory the upper division of the
+graduation is marked 12.6, because this represents the quantity of fat
+which remains in the ether-alcohol mixture for one liter of milk. From
+this point the graduation is extended downward to ninety-five, which,
+for ten cubic centimeters of milk, represents 0.95 gram. After the fat
+has separated, enough ninety-five per cent alcohol is added to bring
+the upper surface exactly to the graduation 12.6. The number of grams
+per liter of milk is then read directly from the scale.</p>
+
+<p>In respect of applicability, the observation made regarding Soxhlet’s
+areometric method may be repeated.</p>
+
+<p>In practical work in this country the lactobutyrometer is no longer
+used, but many of the recorded determinations of fat in milk have been
+made by this method.</p>
+
+<p><b>469. Volumetric Methods.</b>—For practical purposes, the volumetric
+methods of estimating fat in milk have entirely superseded all the
+<span class="pagenum"><a id="Page_497"></a>[Pg 497]</span>
+other processes. It has been found that the fat readily separates in a
+pure state from the other constituents of milk whenever the casein is
+rendered completely soluble; whereas no process has yet been devised
+whereby the fat can be easily separated in a pure state from milk
+which has not been treated with some reagent capable of effecting a
+solution of the casein. The volumetric methods may be divided into two
+classes; <i>viz.</i>, (1) Those in which the fat is separated by the
+simple action of gravity, and (2) those in which the natural action
+of gravity is supplanted by centrifugal motion. Each of these classes
+embraces a large number of variations and some of the typical ones will
+be described in the following paragraphs. As solvents for the casein a
+large number of reagents has been used, including alkalies and single
+and mixed acids. In practice, preference is given to the least complex
+and most easily prepared solvents.</p>
+
+<p><b>470. Method Of Patrick.</b>—A typical illustration of the method
+of collecting the fat after solution of the casein, without the aid of
+whirling, is found in the process devised by Patrick.<a id="FNanchor_460" href="#Footnote_460" class="fnanchor">[460]</a></p>
+
+<p>The solvent employed is a mixture of acetic, sulfuric and hydrochloric
+acids, saturated with sodium sulfate, in the respective volumetric
+proportions of nine, five and two. The separation is accomplished in a
+large test tube drawn out near the top into a constricted neck which is
+graduated to measure the volume of the separated fat or to give direct
+percentage results.</p>
+
+<p>The tube should have a content of about twenty-five cubic centimeters
+below the upper mark on the neck. In use 10.4 cubic centimeters of
+milk and a sufficient quantity of the mixed acids to fill it nearly
+to the upper mark are placed in the tube, together with a piece of
+pumice stone, and the mixture boiled. On cooling below 100°, the fat
+will separate and the volume thereof may be measured in the constricted
+portion of the tube. The volume of the fat may be converted into weight
+on multiplying by 0.88 at 60°, or more conveniently the percentage of
+fat be taken from a table. In practice, the tube is filled with the
+milk and acid mixture nearly up to the neck, its contents well mixed
+and additional acid mixture added until the liquid is raised in the
+tube above the neck. After mixing a second time, the contents are
+<span class="pagenum"><a id="Page_498"></a>[Pg 498]</span>
+boiled for five minutes and the fat allowed to collect in the expanded
+part of the tube above the neck. When the fat has collected, the
+mixture is boiled gently a second time for a few minutes. By this
+treatment the fat is mixed with the upper portions of the acid liquid
+and clarified. The clearing of the fat may be hastened by sprinkling
+over it a little effloresced sodium sulfate. The fat is brought into
+the graduated neck by opening a small orifice in the belly of the tube,
+which is closed by means of a rubber band. When the temperature has
+reached 60°, the space occupied by the fat is noted and the numbers
+obtained express the percentage of fat in the sample.</p>
+
+<p>This process is illustrative of the principle of analysis, but is no
+longer used in analytical determinations.</p>
+
+<p><b>471. The Lactocrite.</b>—One of the earliest methods for fat
+estimation in milk, depending on the solution of the casein and the
+collection of the fat by means of whirling, is based on the use of a
+centrifugal machine known as the lactocrite. This apparatus is modeled
+very like the machine usually employed for creamery work,<a id="FNanchor_461" href="#Footnote_461" class="fnanchor">[461]</a>
+and at one time was extensively used, but it has now given place to less
+troublesome and expensive machines. The acid mixture for freeing the
+fat of casein is composed of glacial acetic acid carrying five per cent
+of sulfuric. The samples of milk are heated with the acid mixture in
+test tubes provided with stoppers and short glass tubes to return the
+condensation products. The hot mixture is poured into a small metallic
+cylindrical cup holding about three cubic centimeters. This cup fits
+by means of an accurately ground shoulder on a metal casing, carrying
+inside a heavy glass graduated tube of small internal diameter. The
+excess of the milk mixture escapes through a small aperture in the
+metallic screw cap of the metal holder. The metal holder is cut away on
+both sides in order to expose the graduations on the glass tube. The
+glass tube is held water-tight by means of perforated elastic washers.
+Thus prepared the tubes are inserted in the radial holes of a revolving
+steel disk previously heated to a temperature of 60°. The whirling is
+accomplished in a few minutes by imparting to the steel disk a speed of
+about 6,000 revolutions per minute. At the end of this operation the
+fat is found in a clear column in the small glass tube and the number
+<span class="pagenum"><a id="Page_499"></a>[Pg 499]</span>
+of the divisions it occupies in this tube is noted. Each division of
+the scale represents one-tenth per cent of fat.</p>
+
+<p>This apparatus is capable of giving accurate results when all its parts
+are in good working order. In this laboratory the chief difficulty which
+its use has presented is in keeping the joints in the glass metal tube tight.</p>
+
+<p>This description of the apparatus is given to secure an illustration of
+the principle involved, a principle which has been worked out in later
+times into some of the most rapid and practical processes of estimating
+fat in milk.</p>
+
+<p><b>472. Modification of Lindström.</b>—Many modifications have been
+proposed for conducting the determination of fat by means of the
+lactocrite, but they do not involve any new principle and are of
+doubtful merit. In the modification suggested by Lindström, which
+has attained quite an extended practical application, the solvent
+mixture is composed of lactic and sulfuric acids and the butyrometer
+tubes are so changed as to permit the collection of the fat in the
+graduated neck after whirling, by means of adding water. The apparatus
+is also adjusted to secure the congelation of the fat column before
+its volume is noted.<a id="FNanchor_462" href="#Footnote_462" class="fnanchor">[462]</a>
+The analyst can read the fat volume at his leisure when it is in
+the solid state and is not confused by changes of volume during the
+observation. The best acid mixture has been found to be composed of 100
+volumes of lactic, an equal amount of acetic and fifteen volumes of
+sulfuric acids.<a id="FNanchor_463" href="#Footnote_463" class="fnanchor">[463]</a></p>
+
+<div class="figleft smcap">
+    <img id="FIG_109" src="images/fig109.jpg" alt="" width="200" height="395" >
+    <p class="center">Fig. 109.<br> Babcock’s Butyrometer<br> and Acid Measure.</p>
+</div>
+
+<p id="P_473"><b>473. The Babcock Method.</b>—Among the many quick volumetric
+methods which have been proposed for the determination of fat in
+milk, none has secured so wide an application as that suggested by
+Babcock.<a id="FNanchor_464" href="#Footnote_464" class="fnanchor">[464]</a></p>
+
+<p>The chief point of advantage in the use of this method is found in
+effecting the solution of the casein by means of sulfuric acid of about
+1.83 specific gravity. By this reagent the casein is dissolved in a few
+moments without the aid of any other heat than that generated by mixing
+the milk with the reagent. The bottle in which the separation is made
+is shown in <a href="#FIG_109">Fig. 109</a>. The graduations on the neck are based
+on the use of eighteen grams of milk. To avoid the trouble of weighing, the milk
+<span class="pagenum"><a id="Page_500"></a>[Pg 500]</span>
+is measured from a pipette graduated to deliver eighteen grams of milk
+of the usual specific gravity. While it is true that normal milk may
+vary somewhat in its density, it has been found that a pipette marked
+at 17.6 cubic centimeters delivers a weight which can be safely assumed
+to vary but slightly from the one desired. The graduated bottle holds
+easily thirty-five cubic centimeters of liquid in its expanded portion
+and the volume of milk just noted is mixed with an equal volume of
+sulfuric acid, conveniently measured from the lip cylinder shown in the
+<a href="#FIG_109">figure</a>. The complete mixture of the milk and
+acid is effected by gently rotating the bottle until its contents are
+homogeneous. The final color of the mixture varies from dark brown to black.</p>
+
+<p>While still hot, the bottles are placed in a centrifugal machine and
+whirled for at least five minutes. The most convenient machine, where
+it is available, is the one driven by a jet of steam. The revolutions
+of the centrifugal should be at least 700 per minute for a twenty inch
+and 1,200 for a twelve inch wheel. After five minutes the bottles are
+removed and filled to the upper mark or nearly so with hot water,
+replaced in the machine and whirled for at least one minute. The fat
+will then be found in a clearly defined column in the graduated neck of
+the bottle. In reading the scale, the extreme limits between the lowest
+point marked by the lower meniscus and the highest point marked by the
+edge of the upper meniscus are to be regarded as the termini of the fat
+column.</p>
+
+<p>In testing cream by the babcock process, it may either be diluted until
+<span class="pagenum"><a id="Page_501"></a>[Pg 501]</span>
+the column of fat secured is contained in the graduated part of the
+neck or specially graduated bottles may be used.</p>
+
+<p><i>Condensed Milk</i>: In applying the babcock test to condensed
+milk, it is necessary to weigh the sample and to use only about eight
+grams.<a id="FNanchor_465" href="#Footnote_465" class="fnanchor">[465]</a>
+This quantity is placed in the bottle and dissolved in ten cubic
+centimeters of water and the analysis completed as above. The reading
+noted is multiplied by eighteen and divided by the weight of the sample
+taken.</p>
+
+<p><i>Skim Milk</i>: In determining the fat in skim milk and whey, it is
+desirable to use a bottle of double the usual capacity, but with the same
+graduation on the neck. The percentage of fat noted is divided by two.</p>
+
+<p><i>Cheese</i>: Five grams are a convenient quantity of cheese to
+employ. To this quantity in the bottle are added fifteen cubic
+centimeters of hot water and the flask gently shaken and warmed until
+the cheese is softened. The treatment with acid and whirling are the
+same as described above. The noted reading is multiplied by eighteen
+and divided by five.</p>
+
+<p><b>474. Solution in Amyl Alcohol and Hydrochloric and Sulfuric
+Acids.</b>—Leffmann and Beam have proposed to aid the solution of
+the casein in sulfuric acid by the previous addition to the milk of a
+mixture of equal volumes of amyl alcohol and hydrochloric acid.<a id="FNanchor_466" href="#Footnote_466" class="fnanchor">[466]</a>
+In this process the same graduated flasks may be used as in the
+babcock process, or a special flask may be employed. In this case the
+graduation of the neck is for fifteen cubic centimeters of milk, and
+each one and a half cubic centimeters is divided into eighty-six parts.
+The quantity of milk noted is placed in the flask, together with three
+cubic centimeters of the mixture of amyl alcohol and hydrochloric acid,
+and well shaken. To the mixture, sulfuric acid of 1.83 specific gravity
+is added until the belly of the flask is nearly full and the contents
+well mixed by shaking. When the casein is dissolved, the addition of
+the sulfuric acid is continued until the flask is filled to the upper
+mark and again the contents mixed. It is well to close the mouth of
+the flask with a stopper while shaking. The bottle is placed in a
+centrifugal and whirled for a few moments, when the fat is collected in
+the graduated neck and its volume noted.
+<span class="pagenum"><a id="Page_502"></a>[Pg 502]</span></p>
+
+<p>The process is also known in this country as the beimling method.<a id="FNanchor_467" href="#Footnote_467" class="fnanchor">[467]</a>
+The fat separated in the above process is probably mixed with a little
+fusel oil, and therefore it is advisable to use the specially graduated
+bottle instead of one marked in absolute volumes.<a id="FNanchor_468" href="#Footnote_468" class="fnanchor">[468]</a></p>
+
+<p>The method, when conducted according to the details found in the
+papers cited, gives accurate results, but is somewhat more complicated
+than the babcock process and is not now used to any great extent in
+analytical work.</p>
+
+<p id="P_475"><b>475. Method of Gerber.</b>—The method proposed by Gerber for
+estimating fat in milk is based on the processes of Babcock, Beimling
+and Beam already described. The tubes in which the decomposition of the
+milk and the measurement of the fat are accomplished are of two kinds,
+one open at only one end for milk and the other open at both ends for
+cheese. They are closed during the separation by rubber stoppers.<a id="FNanchor_469" href="#Footnote_469" class="fnanchor">[469]</a></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_110" src="images/fig110.jpg" alt="" width="600" height="450" >
+    <p class="center spb1">Fig. 110. Gerber’s Butyrometers.</p>
+</div>
+
+<p>The apparatus have been greatly improved and simplified since the first
+description of them was published and have come into extensive use in
+Europe and to a limited extent in this country.<a id="FNanchor_470" href="#Footnote_470" class="fnanchor">[470]</a></p>
+
+<p><span class="pagenum"><a id="Page_503"></a>[Pg 503]</span>
+The butyrometer tubes are made of various sizes and shapes, but the
+most convenient are those noted above as shown in <a href="#FIG_110">Fig. 110</a>.</p>
+
+<p>Before adding the strong sulfuric acid, one cubic centimeter of amyl
+alcohol is mixed with the milk in the butyrometer. This admixture
+serves to clarify the fat and render the reading more easy.</p>
+
+<p>The centrifugal is run by hand, and the required speed of rotation is
+given it by means of a cord wrapped spirally about its axis, as shown
+in <a href="#FIG_111">Fig. 111</a>. The cord in the new machines is
+replaced by a leather strap working on a ratchet.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_111" src="images/fig111.jpg" alt="" width="500" height="500" >
+    <p class="center spb1">Fig. 111. Gerber’s Centrifugal.</p>
+</div>
+
+<p>The process is more speedy than that of Babcock, and the results have
+been shown by a large experience to be reliable and accurate.</p>
+
+<p>The sulfuric acid employed is of 1.825 to 1.830 specific gravity. There
+is no danger of loss by the formation of volatile ethers where the
+quantity of amyl alcohol used does not exceed one cubic centimeter.
+In a comparison of the respective merits of the methods of Babcock,
+Thörner and Gerber, made by Hausamann, the first place is awarded to
+the Gerber process.<a id="FNanchor_471" href="#Footnote_471" class="fnanchor">[471]</a>
+In the <a href="#FIG_110">figure 110</a>, the butyrometers marked 2, 5
+<span class="pagenum"><a id="Page_504"></a>[Pg 504]</span>
+and 8 are for milk, and those numbered 1, 3 and 7 are for cream and
+cheese. In conducting the analysis, ten cubic centimeters of the
+sulfuric acid are placed in the butyrometer with one cubic centimeter
+of the amyl alcohol. When mixed, eleven cubic centimeters of the
+milk are added and the contents of the tube well mixed, the tube
+stoppered and placed in the centrifugal. The larger tubes, open at both
+ends, require double the quantities of the reagents mentioned. The
+measurements are made at about 15°.</p>
+
+<p>Minute directions for conducting the analyses with milk, skim milk,
+buttermilk, cream, condensed milk, cheese and butter accompany each
+apparatus.</p>
+
+<h3>PROTEID BODIES IN MILK.</h3>
+
+<p><b>476. Kinds of Proteid Bodies in Milk.</b>—The proteid bodies in
+milk are all found in at least partial solution. Some authorities state
+that a portion of the casein is present in the form of fine particles
+suspended after the manner of the fat globules.<a id="FNanchor_472" href="#Footnote_472" class="fnanchor">[472]</a>
+The number and kind of proteid bodies are not known with definiteness.
+Among those which are known with certainty are casein, albumin, peptone
+and fibrin. The latter body was discovered in milk by Babcock.<a id="FNanchor_473" href="#Footnote_473" class="fnanchor">[473]</a>
+Lactoglobulin and lactoprotein are also names given to imperfectly
+known proteid bodies in milk. Lactoprotein is not precipitated either
+by acids or by heat and is therefore probably a peptone. By far the
+greater part of the proteid matters in milk is casein. Casein has been
+called caseinogen by Halliburton,<a id="FNanchor_474" href="#Footnote_474" class="fnanchor">[474]</a>
+and paracasein by Schulze and Röse.<a id="FNanchor_475" href="#Footnote_475" class="fnanchor">[475]</a>
+Casein has intimate relations to the mineral matters in milk, and is
+probably itself made up of several proteid bodies of slightly differing
+properties. In general all that class of proteid matter contained in
+milk which is precipitated by rennet or a weak acid, or spontaneously
+on the development of lactic acid, is designated by the term casein,
+while the albumins and peptones in similar conditions remain in
+solution. Casein contains phosphorus, presumably as nuclein. Fibrin is
+recognized in milk by the reactions it gives with hydrogen peroxid or
+gum guiacum. The decomposition of hydrogen peroxid is not a certain
+test for fibrin, inasmuch as pus and many other bodies will produce the
+<span class="pagenum"><a id="Page_505"></a>[Pg 505]</span>
+same effect. If the milk decompose hydrogen peroxid, however, before
+and not after boiling, an additional proof of the presence of fibrin
+is obtained, since boiled fibrin does not act on the reagent.<a id="FNanchor_476" href="#Footnote_476" class="fnanchor">[476]</a>
+The gum guiacum test is applied by dipping a strip of filter paper into the
+milk and drying. The solution of gum guiacum is applied to the dried
+paper and the presence of fibrin is recognized by the blue color which
+is produced. The fibrin is probably changed into some other proteid
+during the ripening of cream in which the fibrin is chiefly found. The
+albumin in milk is coagulated by boiling, while the casein remains
+practically unaffected when subjected to that temperature.</p>
+
+<p><b>477. Estimation of Total Proteid Matter.</b>—The total proteid
+matter in milk is determined by any of the general methods applicable
+to the estimation of total nitrogen, but the moist combustion method
+is by far the most convenient. From the total nitrogen, that which
+represents ammonia or other nonproteid nitrogenous bodies, is to
+be deducted and the remainder multiplied by an appropriate factor.
+Practically all the nitrogen obtained is derived from the proteid
+matters and, as a rule, no correction is necessary. The factors
+employed for calculating the weight of proteid matter from the nitrogen
+obtained vary from 6.25 to 7.04. It is desirable that additional
+investigations be made to determine the magnitude of this factor. It
+is suggested that provisionally the factor 6.40 be used. In the method
+adopted by the Association of Official Agricultural Chemists it is
+directed that about five grams of milk be placed in the oxidizing flask
+and treated without previous evaporation exactly as described for the
+estimation of total nitrogen in the absence of nitrates. The nitrogen
+obtained is multiplied by 6.25 to get the total proteid matter.<a id="FNanchor_477" href="#Footnote_477" class="fnanchor">[477]</a>
+In order to prevent the too great dilution of the sulfuric acid, the milk
+may be evaporated to dryness or nearly so before oxidation. In this
+laboratory it is conveniently done by placing the milk first in the
+oxidizing flask, connecting this with the vacuum service and placing
+the flask in hot water. The aqueous contents of the milk are quickly
+given off at a temperature not exceeding 85°, and the time required is
+only a few minutes.
+<span class="pagenum"><a id="Page_506"></a>[Pg 506]</span></p>
+
+<p>The milk may also be dried in dishes made of thin glass or tin foil
+and, after desiccation, introduced with the fragments of the dishes
+into the oxidizing flask.</p>
+
+<p>The preliminary drying in the oxidizing flask is recommended as the
+best.</p>
+
+<p>Söldner oxidizes the nitrogen in human milk by boiling ten cubic
+centimeters thereof for three hours with twenty-five of sulfuric
+acid, fifty milligrams of copper oxid and three drops of a four per
+cent platinic chlorid solution, and, after distilling the ammonia,
+uses the factor 6.39 for calculating the proteid matter. According to
+this author human milk is much less rich in nitrogenous constituents
+than is generally supposed, containing not more than one and a half
+per cent thereof in average samples collected at least a month after
+parturition.<a id="FNanchor_478" href="#Footnote_478" class="fnanchor">[478]</a></p>
+
+<p><b>478. Precipitation of Total Proteids with Copper Sulfate.</b>—This
+method of throwing out the total proteids of milk is due to
+Ritthausen.<a id="FNanchor_479" href="#Footnote_479" class="fnanchor">[479]</a>
+The proteids and fat are precipitated together by the addition of a
+measured volume of copper sulfate solution, containing 63.92 grams
+of the crystallized salt in one liter. The process, as modified by
+Pfeiffer, is conducted as follows:<a id="FNanchor_480" href="#Footnote_480" class="fnanchor">[480]</a></p>
+
+<p>Ten grams of milk are diluted with ten times that much water, five
+cubic centimeters of the copper sulfate solution added and then soda
+lye solution drop by drop until the copper is just precipitated. This
+is determined by testing a few drops of the filtrate with soda lye,
+which, when the copper is precipitated, will give neither a turbidity
+nor a blue color.</p>
+
+<p>The mixture is poured into a dry tared filter, the precipitate washed
+with hot water, dried to constant weight and weighed. The fat is
+removed from the dry pulverized mass by extraction with ether and the
+residue dried and weighed.</p>
+
+<p>The quantity of copper oxyhydrate contained in the precipitate is
+calculated from the quantity of the copper solution used and amounts
+to 0.2026 gram. The casein thus prepared contains not only the copper
+compound named, but also some of the sodium sulfate formed on the
+addition of the soda lye and other mineral salts present in the milk
+and from which it is quite impossible to completely free it. There are
+also many other objections to the process, and the product is of such a
+nature as to render the data obtained by the method very doubtful.
+<span class="pagenum"><a id="Page_507"></a>[Pg 507]</span></p>
+
+<p>This method is chiefly valuable on account of its historical interest.
+Not only are the drying and weighing of the precipitate rendered
+unnecessary by the modern methods of determining nitrogen, but there
+are numerous sources of error which seem to throw doubt on the accuracy
+of the results. The copper hydroxid does not lose all its water even on
+drying at 125°.<a id="FNanchor_481" href="#Footnote_481" class="fnanchor">[481]</a>
+The method therefore can only be recommended for practical purposes
+when all the tedious processes of drying, extracting and calculating
+the quantity of copper oxid are abandoned and the moist washed
+precipitate used directly for the determination of nitrogen.</p>
+
+<p><b>479. Proteid Bodies by Ammonium Sulfate.</b>—All the proteid bodies
+except peptones are precipitated from milk on saturation with ammonium
+sulfate. This method has little analytical value because of the
+presence of nitrogenous salt in the precipitate. Zinc sulfate may be
+substituted for the ammonium salt and thus a determination of proteid
+matter other than peptone be obtained. This result subtracted from the
+total proteid nitrogen gives that due to peptone.</p>
+
+<p id="P_480"><b>480. Total Proteid Matter by Tannic Acid.</b>—For the determination
+of the total proteid matter in milk Sebelien uses the following
+process.<a id="FNanchor_482" href="#Footnote_482" class="fnanchor">[482]</a>
+From three to five grams are diluted with three or four volumes of
+water, a few drops of a saline solution added (sodium phosphate, sodium
+chlorid, magnesium sulfate, <i>et similia</i>), and the proteid bodies
+thrown out with an excess of tannic acid solution. The precipitate
+is washed with an excess of the precipitant and the nitrogen therein
+determined and multiplied by 6.37.</p>
+
+<p><b>481. Separation of Casein from Albumin.</b>—Sebelien prefers
+magnesium sulfate or sodium chlorid to acetic acid as the best reagent
+for separating casein from lactalbumin. Of the two saline reagents
+mentioned, the former is the better. The milk is first diluted
+with a double volume of the saturated saline solution and then the
+fine powdered salt added until saturation is secured. The casein
+is completely thrown out by this treatment, collected on a filter,
+washed with the saturated saline solution, and the nitrogen therein
+<span class="pagenum"><a id="Page_508"></a>[Pg 508]</span>
+determined. The difference between the total and casein nitrogen gives
+the quantity due to the albumin plus the almost negligible quantity due
+to globulin.<a id="FNanchor_483" href="#Footnote_483" class="fnanchor">[483]</a></p>
+
+<p><b>482. Van Slyke’s Method of Estimating Casein.</b>—The casein may
+be separated from the other albuminoids in milk by the procedure
+proposed by Van Slyke.<a id="FNanchor_484" href="#Footnote_484" class="fnanchor">[484]</a>
+Ten grams of the fresh milk are diluted with ninety cubic centimeters
+of water and the temperature raised to 40°. The casein is thrown down
+with a ten per cent solution of acetic acid, of which about one and a
+half cubic centimeters are required. The mixture is well stirred and
+the precipitate allowed to subside. The whey is decanted onto a filter,
+and the precipitate washed two or three times with cold water, brought
+finally onto the filter and washed once or twice with cold water.
+The filter paper and its contents are used for the determination of
+nitrogen in the usual way. The casein is calculated from the nitrogen
+found by multiplication by the factor 6.25. Milk may be preserved
+for this method of determination by adding to it one part of finely
+powdered mercuric chlorid for each two thousand parts of the sample.
+The method is not applicable to curdled milk.</p>
+
+<p><b>483. Theory of Precipitation.</b>—Most authorities now agree in
+supposing that the state of semisolution in which the casein is held in
+milk is secured by the presence of mineral matters in the milk, in some
+intimate combination with the casein. Among these bodies lime is of
+the most importance. The action of the dilute acid is chiefly on these
+mineral bodies, releasing them from combination with the casein, which,
+being insoluble in the milk serum, is precipitated.</p>
+
+<p><b>484. Factors for Calculation.</b>—Most analysts still use the
+common proteid factor, 6.25, in calculating the quantity of proteids
+from the nitrogen determined by analysis. For casein many different
+factors have been proposed. According to Makeris the factor varies from
+6.83 to 7.04.<a id="FNanchor_485" href="#Footnote_485" class="fnanchor">[485]</a>
+Munk gives 6.34 for human and 6.37 for cow milk.<a id="FNanchor_486"
+href="#Footnote_486" class="fnanchor">[486]</a> Sebelien adopts the
+latter factor, and Hammersten nearly the same; <i>viz.</i>, 6.39. The
+weight of authority, at the present time, favors a factor considerably
+above 6.25 for calculating the casein and, in fact, the total proteids
+of milk from the weight of nitrogen obtained.
+<span class="pagenum"><a id="Page_509"></a>[Pg 509]</span></p>
+
+<p><b>485. Béchamp’s Method of Preparing Pure Casein.</b>—The casein in
+about one liter of milk is precipitated by adding gradually about three
+grams of glacial acetic acid diluted with water. The addition of the
+acid is arrested at the moment when litmus paper shows a slightly acid
+reaction. The precipitate thus produced, containing all the casein,
+the milk globules and the microzymes, is separated by filtration,
+being washed by decantation before collecting it on the filter. On
+the filter it is washed with distilled water and the fat removed by
+shaking with ether. The residue is suspended in water, dissolved in the
+least possible quantity of ammonium carbonate, any insoluble residue
+(microzymes, globules) separated by filtration and the pure casein
+thrown out of the filtrate by the addition of acetic acid. The washing
+with distilled water, solution in ammonium carbonate, filtration and
+reprecipitation are repeated three or four times in order to obtain
+the casein entirely free of other substances. Casein thus prepared is
+burned to a carbon free ash with difficulty and contains but little
+over one-tenth per cent of mineral matter.<a id="FNanchor_487" href="#Footnote_487" class="fnanchor">[487]</a></p>
+
+<p><b>486. Separation of Casein with Carbon Dioxid.</b>—The
+supersaturation of the lime compounds of casein with carbon dioxid
+diminishes the solvent action of the lime and thus helps to throw out
+the proteid matter. For this reason Hoppe-Seyler recommends the use
+of carbon dioxid to promote the precipitation of the casein.<a id="FNanchor_488" href="#Footnote_488" class="fnanchor">[488]</a>
+The milk is diluted with about twenty volumes of water and treated, drop by
+drop, with very dilute acetic acid as long as a precipitate is formed.
+A stream of pure carbon dioxid is conducted through the mixture for
+half an hour, and it is allowed to remain at rest for twelve hours,
+when the casein will have all gone down and the supernatant liquid will
+be clear. Albumins and peptones are not thrown out by this treatment.</p>
+
+<p>The method of precipitation is advantageously modified by saturating
+the diluted milk with carbon dioxid before adding the acetic acid, less
+of the latter being required when used in the order just noted.<a id="FNanchor_489" href="#Footnote_489" class="fnanchor">[489]</a></p>
+
+<p><b>487. Separation of Albumin.</b>—In the filtrate from the casein
+<span class="pagenum"><a id="Page_510"></a>[Pg 510]</span>
+precipitate the albumin may be separated by heating to 80°. It may also
+be precipitated by tannic acid, in which case it may contain a little
+globulin. It may also be thrown out by saturation with ammonium or
+zinc sulfates. The latter reagent is to be preferred when the nitrogen
+is to be determined in the precipitate. The quantities of albumin and
+globulin, especially the latter, present in milk are small compared
+with its content of casein.</p>
+
+<p><b>488. Separation of Globulin.</b>—The presence of globulin in milk
+is demonstrated by Sebelien in the following manner:<a id="FNanchor_490" href="#Footnote_490" class="fnanchor">[490]</a>
+The milk is saturated with finely powdered common salt and the precipitate
+produced is separated by filtration. This filtrate in turn is
+saturated with magnesium sulfate. The precipitate produced by this
+reagent is collected on a filter, dissolved in water and precipitated
+by saturation with sodium chlorid. This process is repeated several
+times. The final precipitate is proved to be globulin by the following
+reactions: When a solution of it is dialyzed the proteid body
+separates as a flocculent precipitate, which is easily dissolved in
+a weak solution of common salt. The clear solution thus obtained
+becomes turbid on adding water, and more so after the addition of a
+little acetic acid. A neutral solution of the body is also completely
+precipitated by saturation with sodium chlorid. These reactions serve
+to identify the body as a globulin and not an albumin. All the globulin
+in milk is not obtained by the process, since a part of it is separated
+with the casein in the first precipitation.</p>
+
+<p><b>489. Other Precipitants of Milk Proteids.</b>—Many other reagents
+besides those mentioned have been used for precipitating milk
+proteids, wholly or in part. Among these may be mentioned the dilute
+mineral acids, lactic acid, rennet, mercuric iodid in acetic acid,
+phosphotungstic acid, acid mercuric nitrate, lead acetate and many
+others.</p>
+
+<p>It has been shown by the author that many of these precipitants do not
+remove all the nitrogen but that among others the mercury salts are
+effective.<a id="FNanchor_491" href="#Footnote_491" class="fnanchor">[491]</a>
+When nitrogen is to be subsequently determined the acid mercuric
+nitrate cannot be employed.
+<span class="pagenum"><a id="Page_511"></a>[Pg 511]</span></p>
+
+<p><b>490. Precipitation by Dialysis.</b>—Since the casein is supposed to
+be held in solution by the action of salts it is probable that it may
+be precipitated by removing these salts by dialysis.</p>
+
+<p><b>491. Carbohydrates in Milk.</b>—The methods of determining lactose
+in milk, both by the copper reduction and optical processes, have been
+fully set forth in foregoing paragraphs (<b><a href="#P_243">243</a>,
+<a href="#P_244">244</a>, <a href="#P_259">259</a>, <a href="#P_262">262</a></b>).
+In general, the optical method by double dilution is to be preferred
+as practically exact and capable of application with the minimum
+consumption of time.<a id="FNanchor_492" href="#Footnote_492" class="fnanchor">[492]</a>
+For normal milks a single polarization is entirely sufficient, making
+an arbitrary correction for the volume occupied by the precipitated
+proteids and fat. This correction is conveniently placed at six and a
+half per cent of the volume of milk employed.</p>
+
+<p>The polarimetric estimation of lactose in human milk is likely to give
+erroneous results by reason of the existence in the serum of polarizing
+bodies not precipitable by the reagents commonly employed for the
+removal of proteids.<a id="FNanchor_493" href="#Footnote_493" class="fnanchor">[493]</a>
+The same statement may be made in respect of ass and mare milk. The use
+of acetopicric acid for removing disturbing bodies, as proposed by
+Thibonet<a id="FNanchor_494" href="#Footnote_494" class="fnanchor">[494]</a>
+does not insure results free from error. With the milks above
+mentioned, it is safer to rely on the data obtained by the alkaline
+copper reagents.</p>
+
+<p><b>492. Dextrinoid Body in Milk.</b>—In treating the precipitate,
+produced in milk by copper sulfate, with alcohol and ether for the
+purpose of removing the fat, Ritthausen isolated a dextrin like body
+quite different from lactose in its properties.<a id="FNanchor_495" href="#Footnote_495" class="fnanchor">[495]</a>
+The alcohol ether extract evaporated to dryness leaves a mass not
+wholly soluble in ether, and therefore not composed of fat. This
+residue extracted with ether, presents flocky particles, soluble in
+water and mostly precipitated therefrom by alcohol. This body has a
+slight reducing effect on alkaline copper salts and produces a gray
+color with bismuth nitrate. The quantity of this material is so minute
+as to lead Ritthausen to observe that it does not sensibly affect the
+fat determinations when not separated. It is not clearly demonstrated
+that it is a dextrinoid body and the analyst need not fear that the
+optical determination of milk sugar will be sensibly affected thereby.</p>
+
+<p>Raumer and Späth assume that certain discrepancies, observed by them in
+<span class="pagenum"><a id="Page_512"></a>[Pg 512]</span>
+the data obtained for lactose by the copper and optical methods, are
+due to the presence of this dextrinoid body, but no positive proof
+thereof is adduced.<a id="FNanchor_496" href="#Footnote_496" class="fnanchor">[496]</a></p>
+
+<p><b>493. Amyloid Bodies in Milk.</b>—Herz has observed in milk a body
+having some of the characteristics of starch.<a id="FNanchor_497" href="#Footnote_497" class="fnanchor">[497]</a>
+Observed by the microscope, these particles have some of the
+characteristics of the starch grains of vegetables, with a diameter
+of from ten to thirty-five micromillimeters. They are colored blue by
+iodin. When boiled with water, however, these particles differ from
+starch in not forming a paste. The particles are most abundant in the
+turbid layer found immediately beneath the ether fat solution in the
+areometric process of Soxhlet.</p>
+
+<p>The amyloid particles may be collected from cheese and butter by
+boiling with water, when they settle and can be observed on the
+sediment after freeing of fat by ether.</p>
+
+<p>Some of the statements regarding the adulteration of dairy products
+with starch may have been made erroneously by reason of the natural
+occurrence of these particles.</p>
+
+<p>As in the case of the dextrin like body mentioned above this starchy
+substance, if it really exist, occurs in too minute a quantity to
+influence the results of any of the analytical methods heretofore
+described.</p>
+
+<p>In connection with the supposed presence of an amyloid body in milk,
+it should be remembered that certain decomposition nitrogenous bodies
+give practically the same reactions as are noted above.<a id="FNanchor_498" href="#Footnote_498" class="fnanchor">[498]</a>
+Among these may be mentioned chitin, which occurs very extensively in
+the animal world. The proof of the existence of dextrinoid and amyloid
+bodies in milk rests on evidence which should be thoroughly revised
+before being undoubtedly accepted.</p>
+
+<h3>ANALYSIS OF BUTTER.</h3>
+
+<p><b>494. General Principles.</b>—The general analysis of butter fat
+is conducted in accordance with the methods described in the part of
+this volume devoted to the examination of fats and oils. The methods of
+sampling, drying, filtering, and of determining physical and chemical
+properties, are there developed in sufficient detail to guide the
+<span class="pagenum"><a id="Page_513"></a>[Pg 513]</span>
+analyst in all operations of a general nature. There remain for
+consideration here only the special processes practiced in butter
+analysis and which are not applied to fats in general. These processes
+naturally relate to the study of those properties of a distinctive
+nature, by means of which butter is differentiated from other fats for
+which it may be mistaken or with which it may be adulterated. These
+special studies, therefore, are directed chiefly to the consideration
+of the peculiar physical properties of butter fat, to its content of
+volatile acids and to its characteristic forms of crystallization as
+observed with the aid of the microscope. For dietetic, economic and
+legal reasons, it is highly important that the analyst be able to
+distinguish a pure butter from any substitute therefor.</p>
+
+<p><b>495. Appearance of Melted Butter.</b>—Fresh, pure butter, when
+slowly melted, shows after a short time the butter fat completely
+separated, of a delicate yellow color and quite transparent. Old
+samples of butter do not give a fat layer of equal transparency.
+Oleomargarin, or any artificial butter when similarly treated, gives
+a fat layer opalescent or opaque. By means of this simple test an
+easy separation of pure from adulterated butter may be effected. In
+mixtures, the degree of turbidity shown by the separated fats may be
+regarded as a rough index of the amount of adulteration. In conducting
+the work, the samples of butter, in convenient quantities according to
+the size of the containing vessel, are placed in beakers and warmed
+slowly at a temperature not exceeding 50°. After a lapse of half an
+hour the observations are made.</p>
+
+<p>If one part of the melted butter be shaken with two volumes of warm
+water (40°) and set aside for five minutes the fat is still found as an
+emulsion, while oleomargarin, similarly treated, shows the fat mostly
+separated. This process has some merit, but must not be too highly
+valued.<a id="FNanchor_499" href="#Footnote_499" class="fnanchor">[499]</a></p>
+
+<p><b>496. Microscopic Examination of Butter.</b>—The microscope is
+helpful in judging the purity of butter and the admixture of foreign
+fats, if not in too small quantity to be of any commercial importance,
+can easily be detected by this means.<a id="FNanchor_500" href="#Footnote_500" class="fnanchor">[500]</a>
+The methods of preparing butter fat in a crystalline state are the same
+as those described in paragraphs <b><a href="#P_307">307-309</a></b>. The crystals of butter
+<span class="pagenum"><a id="Page_514"></a>[Pg 514]</span>
+fat differ greatly in appearance with the different methods of
+preparation. When butter is melted, filtered, heated to the boiling
+point of water and slowly cooled, it forms spheroidal crystalline
+masses as seen by the microscope, which present a well defined cross
+with polarized light. This cross is not peculiar to butter fat, but is
+developed therein with greater distinctiveness than in other fats of
+animal origin.</p>
+
+<p>Pure, fresh, unmelted butter, when viewed with polarized light through
+a plate of selenite, presents a field of vision of uniform tint,
+varying with the relative positions of the nicols. When foreign fats,
+previously melted, as in rendering, are mixed with the butter the
+crystallization they undergo disturbs this uniformity of tint and the
+field of vision appears particolored. Old, rancid or melted butter may
+give rise to the same or similar phenomena under like conditions of
+examination. The microscope thus becomes a most valuable instrument for
+sorting butters and in distinguishing them in a preliminary way from
+oleomargarin.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_112" src="images/fig112.jpg" alt="" width="600" height="102" >
+    <p class="center spb1">Fig. 112. Thermometer for Butyrorefractometer.</p>
+</div>
+
+<p><b>497. Judgment of Suspected Butter or Lard by Refractive
+Power.</b>—In discriminating between pure and adulterated butters by
+the aid of the butyrorefractometer (<b><a href="#P_301">301</a></b>), the absolute reading
+of the instrument is of less importance than the difference which is
+detected between the highest permissible numbers, for any degree of
+temperature, and the actual reading obtained at that temperature. These
+differences, within certain limits, do not perceptibly vary with the
+temperature, and heretofore they have been determined with the aid of
+a table, and in this respect the observations have been made the more
+laborious.</p>
+
+<p>Wollny has rendered these tables unnecessary by constructing a
+thermometer in which the mercury column does not indicate degrees of
+temperature, but the highest permissible number for butter or lard
+at the temperature of observation. The scale of the instrument is so
+adjusted as to include temperatures of from 30° to 40°, which renders
+it suited to the examination of butter and lard. The oleothermometer is
+shown in <a href="#FIG_112">Fig. 112</a>.
+<span class="pagenum"><a id="Page_515"></a>[Pg 515]</span></p>
+
+<p>The side of the scale <i>B</i> is for butter and that marked <i>S</i>
+for lard. The use of the instrument is the simplest possible. The
+sample of fat is placed in the prisms in the usual manner. When the
+mercury in the thermometer is at rest, the scale of the instrument
+is read. In the case of a butter, if the reading of the scale give a
+higher number than that indicated by the thermometer, the sample is
+pronounced suspicious and the degree of suspicion is proportional to
+the difference of the two readings.</p>
+
+<p id="P_498"><b>498. Estimation of Water, Fat, Casein, Ash and Salt.</b>—The
+methods proposed by the author for conducting these determinations,
+with minor amendments, have been adopted by the Association of Official
+Agricultural Chemists.<a id="FNanchor_501" href="#Footnote_501" class="fnanchor">[501]</a></p>
+
+<p><i>Water.</i>—The sample held in a flat bottom dish is dried to
+constant weight at about 100°. The weight of the sample used should
+be proportional to the area of the bottom of the dish, which should
+be just covered by the film of melted fat. The dish may be previously
+partly filled with sand, asbestos or pumice stone. The drying may take
+place in the air, in an inert gas or in a vacuum.</p>
+
+<p><i>Fat.</i>—The fat in a sample of butter is readily determined by
+treating the contents of the dish after the determination of water with
+an appropriate solvent.</p>
+
+<p>The process is conducted as follows:</p>
+
+<p>The dry butter from the water determination is dissolved in the dish
+with ether or petroleum spirit. The contents of the dish are then
+transferred to a weighed gooch with the aid of a wash bottle containing
+the solvent, and washed till free of fat. The crucible and contents are
+heated at the temperature of boiling water till the weight is constant.
+The weight of fat is calculated by difference from the data obtained.</p>
+
+<p>The fat may also be determined by drying the butter on asbestos or
+sand, and subsequently extracting the fat by anhydrous alcohol free
+ether. The extract, after evaporation of the ether, is dried to
+constant weight at the temperature of boiling water and weighed.
+<span class="pagenum"><a id="Page_516"></a>[Pg 516]</span></p>
+
+<p><i>Casein or Curd and Ash.</i>—The crucible containing the residue
+from the fat determination is covered and heated, gently at first,
+gradually raising the temperature to just below redness. The cover
+may then be removed and the heat continued till the contents of the
+crucible are white. The loss in weight of the crucible and contents
+represents casein or curd, and the residue is mineral matter or ash.</p>
+
+<p><i>Salt.</i>—It is the usual custom in the manufacture of butter in
+this country to add, as a condiment, a certain proportion of salt.
+In Europe, the butter offered for consumption is usually unsalted. A
+convenient method of determining the quantity of salt is found in the
+removal thereof, from the sample, by repeated washing with hot water
+and in determining the salt in the wash water by precipitation with
+silver nitrate. The operation is conducted as follows: From five to
+ten grams of the sample are placed in a separatory funnel, hot water
+added, the stopper inserted and the contents of the funnel well shaken.
+After standing until the fat has all collected on top of the water, the
+stopcock is opened and the water is allowed to run into an erlenmeyer,
+being careful to let none of the fat globules pass. Hot water is again
+added to the beaker, and the extraction is repeated several times,
+using each time from ten to twenty cubic centimeters of water. The
+resulting washings contain all but a mere trace of the sodium chlorid
+originally present in the butter. The sodium chlorid is determined in
+the filtrate by a set solution of silver nitrate, using a few drops of
+a solution of potassium chromate as an indicator.</p>
+
+<p>It is evident that the quantity of salt may also be determined from the
+ash or mineral matter obtained, as above noted, by the same process.
+If desirable, which is rarely the case, the gravimetric method of
+estimating the silver chlorid may be used.</p>
+
+<p><b>499. Volatile or Soluble Acids.</b>—The distinguishing feature
+of butter, from a chemical point of view, is found in its content of
+volatile or soluble fat acids. Among the volatile acids are reckoned
+those which are carried over in a current of steam at a temperature
+only slightly higher than that of boiling water. As soluble acids are
+<span class="pagenum"><a id="Page_517"></a>[Pg 517]</span>
+regarded those which pass without great difficulty into solution in hot
+water. These two classes are composed essentially of the same acids.
+Of these butyric is the most important, followed by caproic, caprylic
+and capric acids. Small quantities or rather traces of acetic, lauric,
+myristic and arachidic acids are also sometimes found in butter.
+Palmitic, stearic and oleic acids also occur in large quantities. The
+above named acids, in combination with glycerol, form the butter fat.</p>
+
+<p><b>500. Relative Proportion of Ingredients.</b>—The composition
+of butter fat is given differently by different authorities.<a id="FNanchor_502" href="#Footnote_502" class="fnanchor">[502]</a>
+A typical dry butter fat may be regarded as having the following
+composition:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdr" colspan="2">&nbsp;&emsp;Per cent.</td>
+   </tr><tr>
+      <td class="tdl">Butyrin</td>
+      <td class="tdr">7.00</td>
+   </tr><tr>
+      <td class="tdl">Caproin, Caprylin and Caprin&emsp;&emsp;&nbsp;</td>
+      <td class="tdr">2.30</td>
+   </tr><tr>
+      <td class="tdl">Olein</td>
+      <td class="tdr">37.70</td>
+   </tr><tr>
+      <td class="tdl">Palmitin, stearin, etc.</td>
+      <td class="tdr">53.00</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Pure butter fat consists principally of the above glycerids, some
+coloring principles, varying in quantity and composition with the food
+of the animal, and a trace of lecithin, cholesterol, phytosterol and a
+lipochrome.</p>
+
+<p><b>501. Estimation of Volatile or Soluble Acids.</b>—The volatile
+or soluble acids in butter fat are estimated by the methods already
+described (<b><a href="#P_349">349</a>, <a href="#P_351">351</a></b>).
+In practice preference is given to the method of determining volatile
+acids, based on the principle that under standard conditions
+practically all the acids of this nature are secured in a certain
+volume of the distillate. This assumption is not strictly true, but the
+method offers a convenient and reliable manner of obtaining results
+which, if not absolute, are at least comparative.</p>
+
+<p>The quantity of acid distilled is determined by titration with tenth
+normal alkali and for convenience the data are expressed in terms of
+the volume of the alkali consumed. Five grams of normal butter fat
+will give a distillate, under the conditions given, requiring about
+twenty-eight cubic centimeters of tenth normal alkali for complete
+saturation. This is known as the reichert-meissl number. Occasionally
+this number may rise to thirty-two or may sink to twenty-five. Cases
+<span class="pagenum"><a id="Page_518"></a>[Pg 518]</span>
+have been reported where it fell below the latter number, but such
+samples cannot be regarded as normal butter.</p>
+
+<p>The determination of the reichert-meissl number is the most important
+of the chemical processes applied to butter fat analysis.</p>
+
+<p><b>502. Saponification Value and Reichert Number.</b>—It may often be
+convenient to make the same sample of butter fat serve both for the
+determination of the saponification value and of the reichert number.
+For this purpose it is convenient to use exactly five grams of the
+dry filtered fat. The saponification may be accomplished either under
+pressure or by attaching a reflux condenser to the flask as suggested
+by Bremer.<a id="FNanchor_503" href="#Footnote_503" class="fnanchor">[503]</a>
+When the saponification, which is accomplished with alcoholic potash
+lye containing about 1.25 grams in each ten cubic centimeters of
+seventy per cent alcohol, is finished, and the contents of the flask
+are cooled, the residual alkali is titrated with a set sulfuric acid
+solution, using phenolphthalein as indicator. When the color has almost
+disappeared, an additional quantity of the indicator is added and the
+titration continued until the liquid is of an amber tint. A sample of
+the alkali, treated as above, is titrated at the same time and from the
+two sets of data obtained, the saponification number is calculated as
+indicated in paragraph (<b><a href="#P_345">345</a></b>).</p>
+
+<p>A few drops of the alcoholic lye are added to the contents of the flask
+and the alcohol removed by evaporation. The residual soap and potassium
+sulfate are dissolved in 100 cubic centimeters of recently boiled
+water, some pieces of pumice added, and the volatile acids removed by
+distillation in the usual way after adding an excess of sulfuric acid.
+It is important to conduct blank distillations in the same form of
+apparatus to determine the magnitude of any corrections to be made.
+The size of the distilling flask and the form of apparatus to prevent
+mechanical projection of sulfuric acid into the distillate should be
+the same in all cases.</p>
+
+<p><b>503. Modification of the Reichert-Meissl Method.</b>—Kreis has
+proposed the use of strong sulfuric acid for saponifying the fats, the
+<span class="pagenum"><a id="Page_519"></a>[Pg 519]</span>
+saponification and distillation being accomplished in one operation.
+A source of error of some inconvenience in this method is due to the
+development of sulfurous acid by the reducing action of the organic
+matter on the oil of vitriol. Pinette proposes to avoid this difficulty
+by adding, before the distillation is begun, sufficient potassium
+permanganate to produce a permanent red coloration. By this means the
+sulfurous acid is completely oxidized and its transfer to the standard
+alkali during distillation entirely prevented. The same result is
+accomplished by Micko by the use of potassium bichromate. The details
+of the manipulation are as follows:<a id="FNanchor_504" href="#Footnote_504" class="fnanchor">[504]</a></p>
+
+<p>About five grams of the fused fat (butter or oleomargarin) are placed
+in a flask of approximately 300 cubic centimeters capacity. After
+cooling, there are added ten cubic centimeters of sulfuric acid
+containing three grams of water to each ninety-seven grams of the
+strongest acid.</p>
+
+<p>The fat and acid are well mixed by a gentle rotatory motion of the
+flask and placed in a water bath at a temperature of 35° (<i>circa</i>)
+for fifteen minutes. At the end of this time the flask is removed from
+the bath and 125 cubic centimeters of water added, little by little,
+keeping the contents cool. Next are added four cubic centimeters of a
+four per cent solution of potassium bichromate. The contents of the
+flask are vigorously shaken and, after five minutes, a solution of
+ferrous sulfate is added gradually from a burette until the reaction
+with a drop of potassium ferrocyanid shows a slight excess of the iron
+salt. The volume of the liquor in the flask is then increased to 150
+cubic centimeters by the addition of water and 110 cubic centimeters
+distilled. After mixing and filtering through a dry filter, the acid
+in 100 cubic centimeters is determined by standard tenth normal barium
+hydroxid solution and the number thus obtained increased by one-tenth
+representing the total acid obtained.</p>
+
+<p><b>504. Elimination of Sulfurous Acid.</b>—Prager and Stern<a id="FNanchor_505" href="#Footnote_505" class="fnanchor">[505]</a>
+propose to eliminate the sulfurous acid by a stream of air, succeeded
+by one of carbon dioxid, and proceed as follows: Five grams of the
+butter fat are brought into a liter flask, ten cubic centimeters of
+strong sulfuric acid are added and the flask is kept for ten minutes at
+<span class="pagenum"><a id="Page_520"></a>[Pg 520]</span>
+30-32° with constant agitation. When the liquid is cold, air is
+bubbled through it until the odor of sulfurous acid has disappeared.
+One hundred cubic centimeters of water are added, with precautions
+against rise of temperature, and carbon dioxid is bubbled through for
+ten minutes. This is then displaced by a stream of air for another ten
+minutes, the delivery tube is washed into the flask with fifty cubic
+centimeters of water and the distillation is effected. The following
+results are quoted:</p>
+
+<p>Cubic centimeters of tenth normal alkali required by five grams of
+butter fat:</p>
+
+<table class="spb1">
+   <tbody><tr class="fs_90">
+      <td class="tdr" colspan="2">&nbsp;</td>
+      <td class="tdc">&nbsp; Reichert-Meissl. &nbsp;</td>
+      <td class="tdc">&nbsp; Prager-Stern. &nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Sample</td>
+      <td class="tdl_wsp"><i>a</i></td>
+      <td class="tdc">29.86</td>
+      <td class="tdc">29.60</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp"><i>b</i></td>
+      <td class="tdc">30.23</td>
+      <td class="tdc">29.65</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp"><i>c</i></td>
+      <td class="tdc">28.34</td>
+      <td class="tdc">27.76</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp"><i>d</i></td>
+      <td class="tdc">28.20</td>
+      <td class="tdc">28.10</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The authors do not comment on the possibility of loss of acids
+other than sulfurous in the stream of air, but they admit that
+further investigation is requisite to render the suggestion of Kreis
+serviceable.</p>
+
+<p><b>505. Errors Due to Poor Glass.</b>—The easy solubility of the glass
+holding the reagents is the cause of some of the difficulties attending
+the determination of the saponification value. The separated silica
+tends to carry down, mechanically, a part of the alkali. This is shown
+by the fact that after the color has been discharged by titration
+with acid and the flask set aside a reappearance of the red color is
+noticed, after a time, beginning at the bottom of the flask.<a id="FNanchor_506" href="#Footnote_506" class="fnanchor">[506]</a>
+In order to avoid difficulties of this nature, either cold saponification
+should be practiced or the digestion vessels used for moist combustion
+in sulfuric acid be employed.</p>
+
+<p>Errors may also be easily introduced by the use of uncalibrated
+burettes and from the employment of varying quantities of the
+phenolphthalein solution.</p>
+
+<p><b>506. Estimation of the Molecular Weight of Butter and Butter
+Substitutes.</b>—Garelli and Carono have proposed a method for
+discriminating between butter and its substitutes by the kryoskopic
+determination of molecular weights.
+<span class="pagenum"><a id="Page_521"></a>[Pg 521]</span></p>
+
+<p>The molecular weights of stearin, palmitin and olein are 890, 806
+and 884, and of butyrin, caproin and caprylin 303, 386 and 470
+respectively. Pure butter, therefore, has a lower mean molecular weight
+than margarin.</p>
+
+<p>The method and apparatus of Beckmann are used in the determination,
+fifteen grams of benzol being employed as a solvent.</p>
+
+<p>The constant for the molecular depression of the benzol is found to be
+53.</p>
+
+<p>The molecular weight obtained with samples of pure butter varied from
+696 to 716, and for oleomargarin from 780 to 883.</p>
+
+<p>The figures obtained with mixtures of twenty, twenty-five, thirty-three
+and fifty per cent of margarin with butter were 761, 720, 728 and 749
+respectively. The method can be relied upon to classify samples as follows:</p>
+
+<ul class="index fs_105">
+<li class="isub3">1. Pure butter.</li>
+<li class="isub3">2. Butter containing margarin.</li>
+<li class="isub3">3. Suspicious butter.<a id="FNanchor_507" href="#Footnote_507" class="fnanchor">[507]</a></li>
+</ul>
+
+<p><b>507. Substitutes and Adulterants of Butter.</b>—In this country,
+butter is never adulterated with cocoa or sesame oil, as is sometimes
+the case in other lands. The common substitute for butter here is
+oleomargarin, and the most common butter adulterant, neutral lard. The
+methods of analyses, by means of which these bodies can be identified,
+have already been sufficiently described. By the use of certain
+digestive ferments and other bodies, butter may be made to hold an
+excessive quantity of casein, sugar and water in the form of a somewhat
+permanent emulsion.<a id="FNanchor_508" href="#Footnote_508" class="fnanchor">[508]</a>
+This form of adulteration is revealed at once on melting the sample.</p>
+
+<p><b>508. Furfurol Reaction with Sesame Oil.</b>—Olive oil and sometimes
+butter are mixed with the cheaper body, sesame oil. The latter is
+detected with certainty, from the red coloration it gives when mixed
+with furfurol and hydrochloric acid. Instead of furfurol, some body
+yielding it when subjected to the action of hydrochloric acid,
+<i>viz.</i>, sucrose or a pentose sugar, may be used. It has been
+found by Wauters, however, that an alcoholic solution of two grams of
+furfuraldehyd in 100 cubic centimeters of alcohol is the best reagent.
+One-tenth of a cubic centimeter of this reagent is used for each
+test.<a id="FNanchor_509" href="#Footnote_509" class="fnanchor">[509]</a></p>
+
+<p><span class="pagenum"><a id="Page_522"></a>[Pg 522]</span>
+The test is made as follows: The quantity of the furfuraldehyd solution
+mentioned above is mixed with ten cubic centimeters of hydrochloric
+acid, and there are added, without mixing, an equal volume of the
+suspected oil. On standing, a red coloration is produced at the zone of
+separation of the two liquids. If the oil be sesame, the coloration is
+produced instantly. As little as one per cent of sesame in a mixed oil
+will show the color in two minutes. The manipulation is also varied by
+shaking together the reagents and the melted butter. Turmeric, which
+is sometimes used in coloring butter, also gives the rose-red color
+when treated with hydrochloric acid, but turmeric supplies its own
+furfuraldehyd. It is easy to distinguish therefore the coloration due
+to sesame oil, which is developed only when furfuraldehyd is present,
+from that due to the turmeric, which is produced without the aid of the
+special reagent.</p>
+
+<p><b>509. Butter Colors.</b>—Where cows are deprived of green food and
+root crops, such as carrots, and kept on a poorly balanced ration, the
+butter made from their milk may be almost colorless. To remedy this
+defect it is quite a common practice to color the product artificially.
+Almost the sole coloring matter used in this country is anatto.<a id="FNanchor_510" href="#Footnote_510" class="fnanchor">[510]</a>
+Other coloring matters which are occasionally employed are turmeric,
+saffron, marigold leaves, yellow wood (<i>Chlorophora tinctoria</i>),
+carrot juice, chrome yellow (lead chromate) and dinitrocresol.</p>
+
+<p>The use of small quantities of anatto, turmeric or saffron is
+unobjectionable, from a sanitary point of view, but this is not the
+case with such a substance as lead chromate. The detection of anatto or
+saffron in butter may be accomplished by the method of Cornwall.<a id="FNanchor_511" href="#Footnote_511" class="fnanchor">[511]</a>
+About five grams of the warm filtered fat are dissolved in about fifty
+cubic centimeters of ordinary ether, in a wide tube, and the solution
+is vigorously shaken for from ten to fifteen seconds, with from twelve
+to fifteen cubic centimeters of a very dilute solution of caustic
+potash or soda in water, only alkaline enough to give a distinct
+reaction with turmeric paper, and to remain alkaline after separating
+from the ethereal fat solution. The corked tube is set aside, and in
+a few hours, at most, the greater part of the aqueous solution, now
+<span class="pagenum"><a id="Page_523"></a>[Pg 523]</span>
+colored more or less yellow by the anatto, can be drawn from beneath
+the ether with a pipette or by a stopcock below, in a sufficiently
+clear state to be evaporated to dryness and tested in the usual way
+with a drop of concentrated sulfuric acid.</p>
+
+<p>Sometimes it is well to further purify the aqueous solution by shaking
+it with some fresh ether before evaporating it, and any fat globules
+that may float on its surface during evaporation should be removed by
+touching them with a slip of filter paper; but the solution should not
+be filtered, because the filter paper may retain much of the coloring
+matter.</p>
+
+<p>The dry yellow or slightly orange residue turns blue or violet blue
+with sulfuric acid, then quickly green, and finally brownish or
+somewhat violet this final change being variable, according to the
+purity of the extract.</p>
+
+<p>Saffron can be extracted in the same way; it differs from anatto very
+decidedly, the most important difference being in the absence of the
+green coloration.</p>
+
+<p>Genuine butter, free from foreign coloring matter, imparts at most a
+very pale yellow color to the alkaline solution; but it is important
+to note that a mere green coloration of the dry residue on addition
+of sulfuric acid is not a certain indication of anatto (as some books
+state) because the writer has thus obtained from genuine butter,
+free from foreign coloring matter, a dirty green coloration, but not
+preceded by any blue or violet-blue tint.</p>
+
+<p>Blank tests should be made with the ether.</p>
+
+<p>Turmeric is easily identified by the brownish to reddish stratum that
+forms between the ethereal fat solution and the alkaline solution
+before they are intimately mixed. It may be even better recognized by
+carefully bringing a feebly alkaline solution of ammonia in alcohol
+beneath the ethereal fat solution with a pipette, and gently agitating
+the two, so as to mix them partially.</p>
+
+<p>Another method of separating artificial coloring matter has been
+proposed by Martin.<a id="FNanchor_512" href="#Footnote_512" class="fnanchor">[512]</a></p>
+
+<p>A method of determining the relative amount of butter color has been
+<span class="pagenum"><a id="Page_524"></a>[Pg 524]</span>
+worked out by Babcock.<a id="FNanchor_513" href="#Footnote_513" class="fnanchor">[513]</a></p>
+
+<h3>EXAMINATION OF CHEESE.</h3>
+
+<p><b>510. Composition Of Cheese.</b>—Pure cheese is made from whole
+milk by precipitating the casein with rennet. The precipitated casein
+carries down also the fat of the milk and a little lactose and whey
+remain incorporated with the cheesy mass. The ingredients of cheese
+are therefore those of the whole milk less the greater part of the
+whey, <i>id est</i>, milk sugar, lactalbumin, globulin, soluble mineral
+matters and water. In the conversion of the crude precipitate noted
+above into the cheese of commerce, it is subjected to a ripening
+process which is chiefly conditioned by bacterial action. It is not
+possible here to enter into a discussion of methods of isolating
+and identifying the bacteria which promote or retard the ripening
+process.<a id="FNanchor_514" href="#Footnote_514" class="fnanchor">[514]</a>
+As a rule, about a month is required for the curing process, before the
+cheeses are ready for boxing and shipment. The most important changes
+during ripening take place in the proteid matter, which is so altered
+as to become more palatable and more digestible as a result of the
+bacterial activity.</p>
+
+<p>The percentage composition of the principal cheeses of commerce are
+shown in the following table:<a id="FNanchor_515" href="#Footnote_515" class="fnanchor">[515]</a></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc">&nbsp;</th>
+      <th class="tdc bb">Water,<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc bb">Casein,<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc bb">Fat,<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc bb">Sugar,<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc bb">Ash,<br>&nbsp; Per cent. &nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Cheddar</td>
+      <td class="tdc">34.38</td>
+      <td class="tdc">26.38</td>
+      <td class="tdc">32.71</td>
+      <td class="tdc">2.95</td>
+      <td class="tdc">3.58</td>
+   </tr><tr>
+      <td class="tdl">Cheshire</td>
+      <td class="tdc">32.59</td>
+      <td class="tdc">32.51</td>
+      <td class="tdc">26.06</td>
+      <td class="tdc">4.53</td>
+      <td class="tdc">4.31</td>
+   </tr><tr>
+      <td class="tdl">Stilton</td>
+      <td class="tdc">30.35</td>
+      <td class="tdc">28.85</td>
+      <td class="tdc">35.39</td>
+      <td class="tdc">1.59</td>
+      <td class="tdc">3.83</td>
+   </tr><tr>
+      <td class="tdl">Brie</td>
+      <td class="tdc">50.35</td>
+      <td class="tdc">17.18</td>
+      <td class="tdc">25.12</td>
+      <td class="tdc">1.94</td>
+      <td class="tdc">5.41</td>
+   </tr><tr>
+      <td class="tdl">Neufchatel</td>
+      <td class="tdc">44.47</td>
+      <td class="tdc">14.60</td>
+      <td class="tdc">33.70</td>
+      <td class="tdc">4.24</td>
+      <td class="tdc">2.99</td>
+   </tr><tr>
+      <td class="tdl">Roquefort</td>
+      <td class="tdc">31.20</td>
+      <td class="tdc">27.63</td>
+      <td class="tdc">33.16</td>
+      <td class="tdc">2.00</td>
+      <td class="tdc">6.01</td>
+   </tr><tr>
+      <td class="tdl">Edam</td>
+      <td class="tdc">36.28</td>
+      <td class="tdc">24.06</td>
+      <td class="tdc">30.26</td>
+      <td class="tdc">4.60</td>
+      <td class="tdc">4.90</td>
+   </tr><tr>
+      <td class="tdl">Swiss</td>
+      <td class="tdc">35.80</td>
+      <td class="tdc">24.44</td>
+      <td class="tdc">37.40</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">2.36</td>
+   </tr><tr>
+      <td class="tdl">Full cream,</td>
+      <td class="tdc" rowspan="2">38.60</td>
+      <td class="tdc" rowspan="2">25.35</td>
+      <td class="tdc" rowspan="2">30.25</td>
+      <td class="tdc" rowspan="2">2.03</td>
+      <td class="tdc" rowspan="2">4.07</td>
+   </tr><tr>
+      <td class="tdl_ws1">(mean of 143 analyses)</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>It is evident that the composition of the cheese will vary with
+the milk from which it is made and the manipulation to which it
+is subjected. A good American green cheese made from milk of
+the composition noted below will have the composition which is
+appended.<a id="FNanchor_516" href="#Footnote_516" class="fnanchor">[516]</a></p>
+
+<p class="f120"><b> <span class="smcap">Table Showing Mean Composition of<br>
+Milk and Cheese Made Therefrom.</span></b></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc" colspan="3">&nbsp;</th>
+      <th class="tdc">&nbsp; Milk. &nbsp;</th>
+      <th class="tdc">&nbsp; Cheese. &nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Per</td>
+      <td class="tdl_wsp">cent.</td>
+      <td class="tdl_wsp">water</td>
+      <td class="tdr">87.38</td>
+      <td class="tdr_ws1">36.70</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">fat</td>
+      <td class="tdr">3.73</td>
+      <td class="tdr_ws1">34.18</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">proteids</td>
+      <td class="tdr">3.13</td>
+      <td class="tdr_ws1">23.44</td>
+   </tr><tr>
+      <td class="tdc">”</td>
+      <td class="tdc">”</td>
+      <td class="tdl_wsp">sugar, ash etc.&emsp;&nbsp;</td>
+      <td class="tdr">5.76</td>
+      <td class="tdr_ws1">5.68</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_525"></a>[Pg 525]</span>
+From the above it is seen that in full milk cheese the ratio of fat to
+casein is 1.46: 1, and to solids not fat 1.17: 1. This is a point of
+some importance in judging the purity of a cheese. When the full milk
+of a mixed herd is used the percentage of fat in a cheese will always
+be considerably higher than that of casein.</p>
+
+<p><b>511. Manipulation of the Milk.</b>—When sweet milk is received at
+the cheese factory, a starter of sour milk is added to it in order
+to hasten its ripening. When it is thought that the proper degree of
+acidity has been secured, it is subjected to a rennet test. In this
+test 160 cubic centimeters of the milk are heated to 30° and mixed
+with five cubic centimeters of the rennet solution made by diluting
+five cubic centimeters of the rennet of commerce with fifty cubic
+centimeters of water. The number of seconds required for the milk
+to curdle is noted. The observation is facilitated by distributing
+throughout the milk a few fine fragments of charcoal. The contents of
+the vessel are given a circular motion and, at the moment of setting,
+the movement of the black particles is suddenly arrested. If coloring
+matter be added to the milk, it should be done before it becomes sour.
+The quantity of rennet required is determined by the nature of the
+cheese which it is desired to make. For a cheese to be rapidly cured,
+enough rennet should be added to produce coagulation in from fifteen
+to twenty minutes, and when slow curing is practiced in from thirty
+to forty-five minutes. When the mass is solid so that it can be cut
+with a knife, the temperature is raised to 37°, and it is tested on a
+hot iron until it forms threads an eighth of an inch in length. This
+test is made by applying an iron heated nearly to redness to the curd.
+When the curd is in proper condition threads from a few millimeters to
+two centimeters in length are formed, when the iron is withdrawn. The
+longer threads indicate, but only to a limited extent, a higher degree
+of acidity.<a id="FNanchor_517" href="#Footnote_517" class="fnanchor">[517]</a>
+This test is usually made about two and one-half hours from the time of
+coagulation. The whey is then drawn off through a strainer and the curd
+is placed on racks with linen bottoms in order that the residual whey
+may escape, the curd being stirred meanwhile. In from fifteen to twenty
+<span class="pagenum"><a id="Page_526"></a>[Pg 526]</span>
+minutes it can be cut into blocks eight or ten inches square and turned
+over. This is repeated several times in order to facilitate the escape
+of the whey. When the curd assumes a stringy condition, it is run
+through a mill and cut into small bits and is ready for salting, being
+cooled to 27° before the salt is added. From two to three pounds of
+salt are used for each 100 pounds of curd. The curd is then placed in
+the molds and pressed into the desired form. The cheeses thus prepared
+are placed on shelves in the ripening room and the rinds greased. They
+should be turned and rubbed every day during the ripening, which takes
+place at a temperature of from 15° to 18°.<a id="FNanchor_518" href="#Footnote_518" class="fnanchor">[518]</a></p>
+
+<p><b>512. Official Methods of Analysis.</b>—The methods of cheese
+analysis recommended by the Association of Official Agricultural
+Chemists are provisional and are not binding on its members. They are
+as follows:<a id="FNanchor_519" href="#Footnote_519" class="fnanchor">[519]</a></p>
+
+<p><i>Preparation of Sample.</i>—Where the cheese can be cut, a narrow
+wedge reaching from the edge to the center will more nearly represent
+the average composition than any other sample. This should be chopped
+quite fine, with care to avoid evaporation of water, and the several
+portions for analysis taken from the mixed mass. When the sample is
+obtained with a cheese trier, a plug perpendicular to the surface
+one-third of the distance from the edge to the center of the cheese
+more nearly represents the average composition than any other. The
+plug should either reach entirely or half way through the cheese. For
+inspection purposes the rind may be rejected, but for investigations
+where the absolute quantity of fat in the cheese is required the rind
+should be included in the sample. It is well, when admissible, to
+secure two or three plugs on different sides of the cheese, and, after
+splitting them lengthwise with a sharp knife, use portions of each for
+the different determinations.</p>
+
+<p><i>Determination of Water.</i>—From five to ten grams of cheese are
+placed in thin slices in a weighed platinum or porcelain dish which
+contains a small quantity of freshly ignited asbestos to absorb the
+fat. The dish is heated in a water oven for ten hours and weighed; the
+loss in weight is considered as water. If preferred, the dish may be
+placed in a desiccator over concentrated sulfuric acid and dried to
+<span class="pagenum"><a id="Page_527"></a>[Pg 527]</span>
+constant weight. In some cases this may require as much as two months.
+The acid should be renewed when the cheese has become nearly dry.</p>
+
+<p><i>Determination of Ether Extract.</i>—Grind from five to ten grams
+of cheese in a small mortar with about twice its weight of anhydrous
+copper sulfate. The grinding should continue until the cheese is finely
+pulverized and evenly distributed throughout the mass, which will have
+a uniform light blue color. This mixture is transferred to a glass tube
+having a strong filter paper, supported by a piece of muslin, tied over
+one end. Put a little anhydrous copper sulfate into the tube next to
+the filter before introducing the mixture containing the cheese. On top
+of the mixture place a tuft of ignited asbestos, and place the tube in
+a continuous extraction apparatus and treat with anhydrous ether for
+fifteen hours. Dry the fat obtained at 100° to constant weight.</p>
+
+<p><i>Determination of Nitrogen.</i>—The nitrogen is determined by the
+kjeldahl method, using about two grams of cheese, and multiplying the
+percentage of nitrogen found by 6.25 for proteid compounds.</p>
+
+<p><i>Determination of Ash.</i>—The dry residue from the water
+determination may be used for the ash determination. If the cheese be
+rich in fat, the asbestos will be saturated therewith. This may be
+carefully ignited and the fat allowed to burn, the asbestos acting as a
+wick. No extra heat should be applied during this operation, as there
+is danger of spurting. When the flame has died out, the burning may be
+completed in a muffle at low redness. When desired, the salt may be
+determined in the ash in the manner specified under butter
+(<b><a href="#P_498">498</a></b>).</p>
+
+<p><i>Determination of Other Constituents.</i>—The sum of the percentages
+of the different constituents, determined as above, subtracted from 100
+will give the amount of organic acids, milk sugar etc., in the cheese.</p>
+
+<p><b>513. Process of Mueller.</b>—The process of Müller,<a id="FNanchor_520" href="#Footnote_520" class="fnanchor">[520]</a>
+as modified by Kruger,<a id="FNanchor_521" href="#Footnote_521" class="fnanchor">[521]</a>
+is conducted as follows: About ten grams of a good average sample of
+cheese are rubbed in a porcelain mortar with a mixture of three parts
+of alcohol and one part of ether. After the mixed liquids have been in
+<span class="pagenum"><a id="Page_528"></a>[Pg 528]</span>
+contact with the cheese five or ten minutes they are poured upon a
+weighed filter of from fifteen to sixteen centimeters diameter, and
+this process is repeated from one to three times, after which the
+contents of the mortar are brought upon the filter. The filtrate
+is received in a weighed flask, the alcohol ether driven off by
+evaporation and the residue dried. Since it is difficult to get all the
+particles of cheese free from the mortar, it is advisable to perform
+the above process in a weighed dish which can afterwards be washed
+thoroughly with ether and alcohol and dried and the amount of matter
+remaining thereon accounted for. The residue remaining in the flask
+after drying is treated several times with pure warm ether, and the
+residue also remaining upon the filter mentioned above is completely
+extracted with ether. The dried residue obtained in this way from the
+filter plus the residue in the flask which received the filtrate, plus
+the amount left upon the dish in which the cheese was originally rubbed
+up, constitute the total dry matter of the cheese freed of fat. All
+the material soluble in ether should be collected together, dried and
+weighed as fat.</p>
+
+<p>By this process the cheesy mass is converted into a fine powder which
+can be easily and completely freed from fat by ether, and can be dried
+without becoming a gummy or horny mass.</p>
+
+<p>For the estimation of the nitrogen, about three grams of the well
+grated cheese are used and the nitrogen determined by moist combustion
+with sulfuric acid.<a id="FNanchor_522" href="#Footnote_522" class="fnanchor">[522]</a></p>
+
+<p>For the estimation of ash, about five grams are carbonized, extracted
+with water, and the ash determined as described below.<a id="FNanchor_523" href="#Footnote_523" class="fnanchor">[523]</a></p>
+
+<p>Char from two to three grams of the substance and burn to whiteness
+at the lowest possible red heat. If a white ash cannot be obtained in
+this manner, exhaust the charred mass with water, collect the insoluble
+residue on a filter, burn, add this ash to the residue from the
+evaporation of the aqueous extract and heat the whole to a low redness
+till the ash is white.</p>
+
+<p><b>514. Separation of Fat from Cheese.</b>—It is often desirable to
+secure a considerable quantity of the cheese fat for physical and
+chemical examination without the necessity of effecting a complete
+quantitive separation. In this laboratory this is accomplished by the
+method of Henzold.<a id="FNanchor_524" href="#Footnote_524" class="fnanchor">[524]</a>
+The cheese, in quantities of about 300 grams, is cut into fragments
+<span class="pagenum"><a id="Page_529"></a>[Pg 529]</span>
+about the size of a pea and treated with 700 cubic centimeters of
+potash lye, which has previously been brought to a temperature of about
+20°. The strength of the lye should be such that about fifty grams of
+the caustic potash are contained in each liter of the solution.</p>
+
+<p>The treatment is conveniently conducted in a wide neck flask and the
+solution of the casein is promoted by vigorous shaking. After from five
+to ten minutes, it will be found that the casein is dissolved and the
+fat is found swimming upon the surface of the solution in the form of
+lumps. The lumps of fat are collected in as large a mass as possible by
+a gentle shaking to and fro. Cold water is poured into the flask until the
+fat is driven up into the neck, whence it is removed by means of a spoon.</p>
+
+<p>The fat obtained in this way is washed a few times with as little cold
+water as possible in order to remove the residue of potash lye which
+it may contain. Experience shows that the fat by this treatment is
+not perceptibly attacked by the potash lye. In a short time, by this
+procedure, the fat is practically all separated and is then easily
+prepared for chemical analysis by filtering and drying in the manner
+already described (<b><a href="#P_283">283</a></b>). The fat may also be separated, but
+with less convenience, by partially drying the sample, reducing it to
+a finely divided state and applying any of the usual solvents. The
+solvent is removed from the extract by evaporation and the residual fat
+is filtered and prepared for examination as usual.</p>
+
+<p><b>515. Filled Cheese.</b>—The skim milk coming from the separators
+is unfortunately too often used for cheese making. The abstracted fat
+is replaced with a cheaper one, usually lard. These spurious cheeses
+are found in nearly every market and are generally sold as genuine.
+The purchasers only discover the fraud when the cheese is consumed.
+Many of the States have forbidden by statute the manufacture and sale
+of this fraudulent article. Imported cheeses may also be regarded
+with suspicion, inasmuch as the method of preparing filled cheese is
+well known and extensively practiced abroad. A mere determination of
+the percentage of fat in the sample is not an index of the purity of
+the cheese. It is necessary to extract the fat by one of the methods
+already described and, after drying and filtering, to submit the
+suspected fat to a microscopic and chemical examination. A low content
+<span class="pagenum"><a id="Page_530"></a>[Pg 530]</span>
+of volatile fat acid and the occurrence of crystalline forms foreign to
+butter will furnish the data for a competent judgment.</p>
+
+<p>When the reichert-meissl number falls below twenty-five the sample
+may be regarded with suspicion. The detection of the characteristic
+crystals of lard or tallow is reliable corroborating evidence
+(<b><a href="#P_308">308</a></b>).</p>
+
+<p>It is stated by Kühn<a id="FNanchor_525" href="#Footnote_525" class="fnanchor">[525]</a>
+that the margarin factory of Mohr, at Bahrenfeld-Altona, has made for
+many years a perfect emulsion of fat with skim milk. This product has
+been much used in the manufacture of filled cheese which is often found
+upon the German market.</p>
+
+<p><b>516. Separation of the Nitrogenous Bodies in Cheese.</b>—The
+general methods of separation already described for proteid bodies
+(<b><a href="#P_417">417-425</a></b>) are also applicable to the different nitrogenous
+bodies present in cheese, representing the residue of these bodies
+as originally occurring in the milk, and also the products which are
+formed therefrom during the period of ripening. For practical dietary
+and analytical purposes, these bodies may be considered in three groups:</p>
+
+<p>(<i>a</i>) The useless (from a nutrient point of view) nitrogenous
+bodies, including ammonia, nitric acid, the phenylamido-propionic
+acids, tyrosin, leucin and other amid bodies.</p>
+
+<p>(<i>b</i>) The albumoses and peptones, products of fermentation soluble
+in boiling water.</p>
+
+<p>(<i>c</i>) The caseins and albuminates, insoluble in boiling water.</p>
+
+<p>The group of bodies under (<i>a</i>), according to Stutzer, may be
+separated from the groups (<i>b</i>) and (<i>c</i>) by means of
+phosphotungstic acid. For this purpose a portion of an intimate
+mixture of fine sand and cheese (100 cheese, 400 sand) corresponding
+to five grams of cheese, is shaken for fifteen minutes with 150 cubic
+centimeters of water. After remaining at rest for another fifteen
+minutes 100 cubic centimeters of dilute sulfuric acid (one acid, three
+water) are added, followed by treatment with the phosphotungstic acid
+as long as any precipitate is produced. The mixture is thrown on a
+filter and the insoluble matters washed with dilute sulfuric acid until
+the filtrate amounts to half a liter. Of this quantity an aliquot part
+(200 cubic centimeters) is used for the determination of nitrogen. From
+<span class="pagenum"><a id="Page_531"></a>[Pg 531]</span>
+the quantity of nitrogen found, that representing the ammonia, as
+determined in a separate portion, is deducted and the remainder
+represents the nitrogen present in the cheese as amids.<a id="FNanchor_526" href="#Footnote_526" class="fnanchor">[526]</a></p>
+
+<p><i>Albumoses and Peptones.</i>—Albumoses and peptones are determined
+in cheese by the following method:<a id="FNanchor_527" href="#Footnote_527" class="fnanchor">[527]</a>
+A quantity of the sand mixture already described, corresponding to five
+grams of the cheese, is treated with about 100 cubic centimeters of
+water, heated to boiling, and the clear liquid above the sand poured
+into a flask of half a liter capacity. The extraction is continued with
+successive portions of water in like manner until the volume of the
+extract is nearly half a liter. When cold, the volume of the extract is
+completed to half a liter with water, the liquor filtered, 200 cubic
+centimeters of the filtrate treated with an equal volume of dilute
+sulfuric acid (one to three) and phosphotungstic acid added until no
+further precipitate takes place. The nitrogen is determined in the
+precipitate after filtration and washing with dilute sulfuric acid.</p>
+
+<p><i>Casein and Albuminates.</i>—The quantity of casein and albuminates
+in cheese is calculated by subtracting from the total nitrogen that
+corresponding to ammonia, amids, that in the indigestible residue and
+that corresponding to the albumose and peptone. In three samples of
+cheese, <i>viz.</i>, camembert, swiss, and gervais, Stutzer found the
+nitrogen, determined as above, distributed as follows:<a id="FNanchor_528" href="#Footnote_528" class="fnanchor">[528]</a></p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdc">&nbsp;Camembert.&nbsp;</td>
+      <td class="tdc">&nbsp;Swiss.&nbsp;</td>
+      <td class="tdc">&nbsp;Gervais.&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">N as ammonia</td>
+      <td class="tdc">13.0</td>
+      <td class="tdc">3.7</td>
+      <td class="tdc">1.6</td>
+   </tr><tr>
+      <td class="tdl">N as amids</td>
+      <td class="tdc">38.5</td>
+      <td class="tdc">9.0</td>
+      <td class="tdc">5.2</td>
+   </tr><tr>
+      <td class="tdl">N as albumose peptone</td>
+      <td class="tdc">30.5</td>
+      <td class="tdc">8.6</td>
+      <td class="tdc">15.5&#8199;</td>
+   </tr><tr>
+      <td class="tdl">N indigestible</td>
+      <td class="tdc">&#8199;4.0</td>
+      <td class="tdc">2.4</td>
+      <td class="tdc">8.6</td>
+   </tr><tr>
+      <td class="tdl">N as casein, albuminates</td>
+      <td class="tdc">14.0</td>
+      <td class="tdc">76.3&#8199;</td>
+      <td class="tdc">69.1&#8199;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><i>Ammoniacal Nitrogen.</i>—The ammoniacal nitrogen is determined by
+mixing a quantity of the sand-cheese corresponding to five grams of
+cheese, with 200 cubic centimeters of water, adding an excess of barium
+carbonate and collecting the ammonia by distillation in the usual way.</p>
+
+<p><i>Digestible Proteids.</i>—The digestible proteids in cheese are
+determined by the process of artificial digestion, which will be described
+in the part of this volume treating of the nutritive value of foods.
+<span class="pagenum"><a id="Page_532"></a>[Pg 532]</span></p>
+
+<p>These data show the remarkable changes which the proteids undergo where
+the ripening is carried very far as in the camembert cheese.</p>
+
+<p><b>517. Koumiss.</b>—Fermented mare milk has long been a favorite
+beverage in the East, where it is known as koumiss. In Europe and
+this country cow milk is employed in the manufacture of fermented
+milk, although it is less rich in lactose than mare milk. The process
+of manufacture is simple, provided a suitable starter is at hand.
+A portion of a previous brewing is the most convenient one, the
+fermentation being promoted by the addition of a little yeast. After
+the process of fermentation is finished the koumiss is placed in
+bottles and preserved in a horizontal position in a cellar, where the
+temperature is not allowed to rise above 12°.</p>
+
+<p><b>518. Determination of Carbon Dioxid.</b>—The carbon dioxid in
+koumiss is conveniently estimated by connecting the bottle by means
+of a champagne tap with a system of absorption bulbs.<a id="FNanchor_529" href="#Footnote_529" class="fnanchor">[529]</a>
+The exit tube from the koumiss bottle passes first into an erlenmeyer,
+which serves to break and retain any bubbles that pass over. The water is
+next removed by means of sulfuric acid. The koumiss bottle is placed in
+a bath of water which is raised to the boiling point as the evolution
+of the gas is accomplished. The arrangement of the apparatus is shown
+in <a href="#FIG_113">Fig. 113</a>. At the end of the operation any residual
+carbon dioxid in the apparatus is removed by aspiration after removing
+the tap and connecting it with a soda-lime tube to hold the carbon
+dioxid in the air. A large balance suited to weighing the koumiss
+bottle is required for this determination. The carbon dioxid may also
+be determined, but less accurately, by loss of weight in the koumiss
+bottle after adding weight of water retained in the apparatus.</p>
+
+<p><b>519. Acidity.</b>—Although koumiss may contain a trace of acetic
+acid, it is best to determine the acid as lactic. The clarification is
+most easily accomplished by mixing the koumiss with an equal volume
+of ninety-five per cent alcohol, shaking and filtering. The first
+filtrate will usually be found clear. If not it is refiltered. In an
+aliquot part of the filtrate the acidity is determined by titration
+with tenth-normal sodium hydroxid solution, using phenolphthalein as
+indicator. The necessary corrections for dilution and volume of the
+precipitated casein are to be made. A linen filter may be used when
+paper is found too slow.
+<span class="pagenum"><a id="Page_533"></a>[Pg 533]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_113" src="images/fig113.jpg" alt="" width="600" height="273" >
+    <p class="center spb1">Fig. 113. Apparatus for Determining Carbon
+             Dioxid in Koumiss.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_534"></a>[Pg 534]</span>
+<b>520. Alcohol.</b>—Half a liter of koumiss, to which 100 cubic
+centimeters of water have been added, is distilled until the distillate
+amounts to 500 cubic centimeters.</p>
+
+<p>If the distillate be turbid 100 cubic centimeters of water are added
+and the distillation repeated. The alcohol is determined by the
+processes described hereafter.</p>
+
+<p><b>521. Lactose.</b>—The milk sugar may be determined by any of
+the methods described, but most conveniently by double dilution and
+polarization (<b><a href="#P_86">86</a></b>).</p>
+
+<p><b>522. Fat.</b>—Evaporate twenty grams of the sample to dryness and
+extract with pure ether or petroleum spirit in the manner already
+described (<b><a href="#P_455">455</a></b>).</p>
+
+<p>The analysis is more quickly accomplished by the volumetric method of
+Babcock or Gerber (<b><a href="#P_473">473-475</a></b>).</p>
+
+<p><b>523. Proteids.</b>—The total proteids are most easily estimated by
+the official kjeldahl method.<a id="FNanchor_530" href="#Footnote_530" class="fnanchor">[530]</a>
+The separation of the proteid bodies is accomplished by the methods
+described in paragraphs <b><a href="#P_475">475-489</a></b>.</p>
+
+<p>In addition to the methods already described for separating the soluble
+and suspended proteid bodies in milk, and which may be used also for
+koumiss, the following should also be mentioned as of especial worth:</p>
+
+<p><i>Separation by Filtration through Porous Porcelain.</i>—A purely
+physical method, and one which is to be recommended by reason of the
+absence of any chemical action upon the different proteid matters,
+is that proposed by Lehmann, depending upon the principle that when
+milk is forced through porous porcelain, the albumin passes through
+together with the milk, sugar and other soluble constituents as a clear
+filtrate, while the casein and fat are perfectly retained.<a id="FNanchor_531" href="#Footnote_531" class="fnanchor">[531]</a></p>
+
+<p>By this method it is quite certain that the albumin and other perfectly
+soluble proteids of milk may be obtained in the purest form.
+<span class="pagenum"><a id="Page_535"></a>[Pg 535]</span></p>
+
+<p><i>Separation by Precipitation with Alum.</i>—Probably the best
+chemical method of separating the two classes of proteid matters
+is that proposed by Schlosmann, which is effected by means of
+precipitating the casein with a solution of alum.<a id="FNanchor_532" href="#Footnote_532" class="fnanchor">[532]</a></p>
+
+<p>The principle of this separation rests upon the fact that a solution
+of potash alum, when added to milk diluted with four or five times its
+volume of water, will completely separate the casein without affecting
+the albumin or globulin. The operation is conducted as follows:</p>
+
+<p>Ten cubic centimeters of the milk are diluted with from three to five
+times that quantity of water and warmed to a temperature of about
+40°. One cubic centimeter of a concentrated solution of potash alum
+is added, the mixture well stirred and the coagula which are formed
+allowed to subside. If the coagulation of the casein does not take
+place promptly, a small addition of the alum solution is made, usually
+not exceeding half a cubic centimeter, until the precipitation is
+complete. The temperature during the process should be kept as nearly
+as possible 40°. After a few minutes, the mixture is poured upon a
+filter and the filtrate, if not perfectly clear, is poured back until
+it is secured free of turbidity. In difficult cases the filtration may
+be promoted by the addition of some common salt or calcium phosphate,
+the latter acting mechanically in holding back the fine particles of
+casein. The precipitate is washed with water at a temperature of 40°,
+and afterwards with alcohol, not allowing the alcohol wash water to
+flow into the filtrate. When the water has been chiefly removed from
+the precipitate by washing with alcohol, the fat of the precipitated
+casein is removed with ether and the residue used for the determination
+of nitrogen in the usual way. The albumin is removed from the filtrate
+by a tannin solution in the manner already described (<b><a href="#P_480">480</a></b>).
+If it be desired to separate the albumin and globulin, the methods
+described in paragraph <b><a href="#P_399">399</a></b> may be used.</p>
+
+<p><b>524. Mercurial Method.</b>—A volumetric method for determining the
+total proteid matter in milk has lately been proposed by Deniges.<a id="FNanchor_533" href="#Footnote_533" class="fnanchor">[533]</a>
+It is based upon the observation that in the precipitation of proteid
+<span class="pagenum"><a id="Page_536"></a>[Pg 536]</span>
+matter by mercury salts, a definite quantity of mercury in proportion
+to the amount of proteid, is carried down therewith. The precipitation
+is made with a mercurial salt of known strength and the excess of the
+mercurial salt in the filtrate is determined by titration. For the
+details of the manipulation, the paper cited above may be consulted.</p>
+
+<p><b>525. Water and Ash.</b>—From two to five grams of the koumiss are
+dried to constant weight in a flat platinum dish over ignited sand,
+asbestos or pumice stone, and the dried residue incinerated.</p>
+
+<p><b>526. Composition of Koumiss.</b>—The composition of koumiss varies
+with the character of the milk used and the extent of the fermentation.
+Some of the data obtained by analysts are given below:<a id="FNanchor_534" href="#Footnote_534" class="fnanchor">[534]</a></p>
+
+<p class="f120 spa1"><b><span class="smcap">Composition of Koumiss.</span></b></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc_bott">Kind of milk.</th>
+      <th class="tdc_bott bb">Water,<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc_bott bb">Sugar,<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc_bott bb">Alcohol,<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc_bott bb">Fat,<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc_bott bb">Proteid,<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc bb">Carbon<br>dioxid,<br>&nbsp; Per cent. &nbsp;</th>
+      <th class="tdc_bott bb">Acidity,<br>&nbsp; Per cent. &nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Cow</td>
+      <td class="tdc">89.32</td>
+      <td class="tdc">4.38</td>
+      <td class="tdc">0.76</td>
+      <td class="tdc">2.08</td>
+      <td class="tdc">2.56</td>
+      <td class="tdc">0.83</td>
+      <td class="tdc">0.47</td>
+   </tr><tr>
+      <td class="tdl">Probably cow skim’d</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">3.95</td>
+      <td class="tdc">1.38</td>
+      <td class="tdc">0.88</td>
+      <td class="tdc">2.89</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">0.82</td>
+   </tr><tr>
+      <td class="tdl">Mare</td>
+      <td class="tdc">91.87</td>
+      <td class="tdc">0.79</td>
+      <td class="tdc">2.89</td>
+      <td class="tdc">1.19</td>
+      <td class="tdc">1.91</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">1.04</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>From the above it is seen that koumiss is made either from whole or
+skim milk, and that the percentage of alcohol may vary within large
+limits, its proportion being inverse to that of the milk sugar.</p>
+
+<p>Koumiss is a beverage which is very palatable, easily digested and one
+which is not appreciated in this country in proportion to its merits,
+especially for the use of invalids.</p>
+
+<h3>AUTHORITIES CITED IN PART SIXTH.</h3>
+<div class="footnotes">
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_400" href="#FNanchor_400" class="label">[400]</a>
+Wiley; Proceedings of the Society for the Promotion of Agricultural Science,
+1889, p. 84. (Omit “food” before idiosyncrasy.)</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_401" href="#FNanchor_401" class="label">[401]</a>
+Pharmaceutical Journal and Transactions, Series 3, Vol. 18, p. 479.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_402" href="#FNanchor_402" class="label">[402]</a>
+The Analyst, 1892, p. 85.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_403" href="#FNanchor_403" class="label">[403]</a>
+Henkel; Wiener Landwirtschaftliche Zeitung, 1888, S. 401: Bulletin No. 24,
+Division of Chemistry, U. S. Department of Agriculture, p. 155.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_404" href="#FNanchor_404" class="label">[404]</a>
+Die Landwirtschaftlichen Versuchs-Stationen, Band 35, S. 351: Bulletin
+No. 24, Division of Chemistry, U. S. Department of Agriculture, p. 151.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_405" href="#FNanchor_405" class="label">[405]</a>
+Baumeister; Milch und Molkerei-Producte, S. 16.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_537"></a>[Pg 537]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_406" href="#FNanchor_406" class="label">[406]</a>
+Bulletins Nos. 9 and 25 of the Office of Experiment Stations, U. S.
+Department of Agriculture: Farmers’ Bulletins Nos. 9 and 29, U. S.
+Department of Agriculture.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_407" href="#FNanchor_407" class="label">[407]</a>
+Annales de Chimie et de Physique, 3e Série, Tome 64, p. 61.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_408" href="#FNanchor_408" class="label">[408]</a>
+Bulletin de la Société Chimique de Paris, 3ᵉ Série, Tome 15-16, p. 248.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_409" href="#FNanchor_409" class="label">[409]</a>
+Vid. op. cit. supra, p. 453.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_410" href="#FNanchor_410" class="label">[410]</a>
+Central-Blatt für medicinische Wissenschaft, Band 34, S. 145.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_411" href="#FNanchor_411" class="label">[411]</a>
+Conn; Farmers’ Bulletins 9 and 25, Office of Experiment Stations, U. S.
+Department of Agriculture: Farmers’ Bulletins 9 and 29, Department of
+Agriculture: Les Microbes et leur Rôle dans la Laiterie Freudenreich:
+Langlois, Le Lait, pp. 95 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_412" href="#FNanchor_412" class="label">[412]</a>
+The Analyst, Vol. 20, p. 157.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_413" href="#FNanchor_413" class="label">[413]</a>
+Vid. op. cit. supra, p. 152.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_414" href="#FNanchor_414" class="label">[414]</a>
+Forschungs-Berichte über Lebensmittel etc., Band 2, S. 368.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_415" href="#FNanchor_415" class="label">[415]</a>
+Vid. op. cit. supra, Band 1, S. 422.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_416" href="#FNanchor_416" class="label">[416]</a>
+Vid. op. cit. supra, S. 372.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_417" href="#FNanchor_417" class="label">[417]</a>
+Hopkins and Powers; Bulletin No. 47, Division of Chemistry,
+U. S. Department of Agriculture, p. 127.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_418" href="#FNanchor_418" class="label">[418]</a>
+Bulletin No. 38, Division of Chemistry, U. S. Department of Agriculture, p. 118.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_419" href="#FNanchor_419" class="label">[419]</a>
+Becke; Die Milchprüfungs-Methoden, S. 45: Rouvier; Le Lait, p. 45.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_420" href="#FNanchor_420" class="label">[420]</a>
+The Analyst, 1890, Vol. 16, p. 170.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_421" href="#FNanchor_421" class="label">[421]</a>
+Rouvier; Le Lait, p. 35.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_422" href="#FNanchor_422" class="label">[422]</a>
+Central-Blatt für Nahrungs und Genussmittel Chemie, Band 13, S. 277.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_423" href="#FNanchor_423" class="label">[423]</a>
+Bulletin No. 46, Division of Chemistry, U. S. Department of Agriculture, p. 36.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_424" href="#FNanchor_424" class="label">[424]</a>
+Journal für Landwirtschaft, 1882, S. 293; 1885, S. 251.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_425" href="#FNanchor_425" class="label">[425]</a>
+Vid. op. cit. supra, 1879, S. 249.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_426" href="#FNanchor_426" class="label">[426]</a>
+Forschungen auf dem Gebiete der Viehhaltung, 1879, S. 265.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_427" href="#FNanchor_427" class="label">[427]</a>
+The Analyst, Vol. 7, p. 129.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_428" href="#FNanchor_428" class="label">[428]</a>
+Vid. op. cit. supra, Vol. 13, p. 26.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_429" href="#FNanchor_429" class="label">[429]</a>
+Bulletin No. 47, Division of Chemistry, U. S. Department of Agriculture, p. 123.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_430" href="#FNanchor_430" class="label">[430]</a>
+This work, Vol. 1, page 411.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_431" href="#FNanchor_431" class="label">[431]</a>
+Bulletin No. 16, Division of Chemistry, U. S. Department of Agriculture, p. 36.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_432" href="#FNanchor_432" class="label">[432]</a>
+Sixth Annual Report Wisconsin Agricultural Experiment Station, p. 64.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_433" href="#FNanchor_433" class="label">[433]</a>
+Fourth Annual Report New York (Geneva) Agricultural Experiment Station, p. 298.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_434" href="#FNanchor_434" class="label">[434]</a>
+Woll; Seventh Annual Report Wisconsin Agricultural Experiment Station, p. 238.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_435" href="#FNanchor_435" class="label">[435]</a>
+The Analyst, 1885, p. 46: Bulletin No. 13, Part 1,
+Division of Chemistry, U. S. Department of Agriculture, p. 86.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_538"></a>[Pg 538]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_436" href="#FNanchor_436" class="label">[436]</a>
+Haidlen; Die Milchprüfungs-Methoden, S. 12.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_437" href="#FNanchor_437" class="label">[437]</a>
+Dingler’s polytechnisches Journal, Band 232, S. 461.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_438" href="#FNanchor_438" class="label">[438]</a>
+Macfarlane; The Analyst, Vol. 18, p. 73.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_439" href="#FNanchor_439" class="label">[439]</a>
+Duclaux; Le Lait, p. 176.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_440" href="#FNanchor_440" class="label">[440]</a>
+Abraham; The Analyst, Vol. 9, p. 22.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_441" href="#FNanchor_441" class="label">[441]</a>
+Gantter; Zeitschrift für analytische Chemie, Band 26, S. 677.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_442" href="#FNanchor_442" class="label">[442]</a>
+Morse, Piggot and Burton; American Chemical Journal, Vol. 9, pp. 108 and 222.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_443" href="#FNanchor_443" class="label">[443]</a>
+Chemiker-Zeitung Repertorium, 1889, S. 228.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_444" href="#FNanchor_444" class="label">[444]</a>
+Journal de Pharmacie et de Chimie, 1890, p. 460.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_445" href="#FNanchor_445" class="label">[445]</a>
+Richmond; The Analyst, Vol. 17, p. 48: Bulletins 28, 31, 35, 38, 43,
+and 46, Division of Chemistry, U. S. Department of Agriculture.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_446" href="#FNanchor_446" class="label">[446]</a>
+Bulletin No. 28, Division of Chemistry, U. S. Department of Agriculture, p. 31.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_447" href="#FNanchor_447" class="label">[447]</a>
+Zeitschrift für analytische Chemie, Band 27, S. 464.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_448" href="#FNanchor_448" class="label">[448]</a>
+Chemical News, Nov. 1889.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_449" href="#FNanchor_449" class="label">[449]</a>
+The Analyst, Vol. 16, p. 67.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_450" href="#FNanchor_450" class="label">[450]</a>
+Vid. op. cit. supra, Vol. 18, p. 53.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_451" href="#FNanchor_451" class="label">[451]</a>
+Vid. op. cit. supra, Vol. 17, p. 81.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_452" href="#FNanchor_452" class="label">[452]</a>
+Chemiker-Zeitung, Band 15, S. 1833.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_453" href="#FNanchor_453" class="label">[453]</a>
+Journal of Analytical Chemistry, 1888, Vol. 2, p. 371:
+Fifth Annual Report Wisconsin Agricultural Experiment Station.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_454" href="#FNanchor_454" class="label">[454]</a>
+Molkerei Zeitung, 1892, No. 1; Chemisches Central-Blatt, 1892, Band 2, S. 429.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_455" href="#FNanchor_455" class="label">[455]</a>
+Chemiker-Zeitung, Band 18, S. 1816; Band 19, S. 348.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_456" href="#FNanchor_456" class="label">[456]</a>
+Zeitschrift für analytische Chemie, Band 32, S. 168.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_457" href="#FNanchor_457" class="label">[457]</a>
+Zeitschrift des Landwirtschaftlichen Vereins in Bayern, 1880;
+Zeitschrift für analytische Chemie, Band 20, S. 452.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_458" href="#FNanchor_458" class="label">[458]</a>
+Bulletin No. 13, Division of Chemistry, U. S. Department of Agriculture, p. 92.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_459" href="#FNanchor_459" class="label">[459]</a>
+Instruction sur l’Emploi du Lactobutyrometer, Paris, 1856
+et 1878: Becke; Die Milchprüfungs-Methoden, S. 66.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_460" href="#FNanchor_460" class="label">[460]</a>
+Bulletin No. 8, Iowa Agricultural Experiment Station, p. 295.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_461" href="#FNanchor_461" class="label">[461]</a>
+Dingler’s polytechnisches Journal, Band 261, S. 219.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_462" href="#FNanchor_462" class="label">[462]</a>
+Milch Zeitung, Band 21, S. 496.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_463" href="#FNanchor_463" class="label">[463]</a>
+Op. cit. supra, Band 22, S. 85.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_464" href="#FNanchor_464" class="label">[464]</a>
+Bulletin No. 24, Wisconsin Agricultural Experiment Station.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_465" href="#FNanchor_465" class="label">[465]</a>
+Bulletin No. 31, Wisconsin Agricultural Experiment Station.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_466" href="#FNanchor_466" class="label">[466]</a>
+The Analyst, Vol. 17, p. 83.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_467" href="#FNanchor_467" class="label">[467]</a>
+Bulletin No. 21, Vermont Agricultural Experiment Station.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_468" href="#FNanchor_468" class="label">[468]</a>
+Vid. op. cit. 67, Vol. 17, p. 144; Vol. 18, p. 130; Vol. 19, p. 62.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_469" href="#FNanchor_469" class="label">[469]</a>
+Chemiker-Zeitung, Band 16, S. 1839.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_470" href="#FNanchor_470" class="label">[470]</a>
+Vid. op. cit. supra, Band 19, S. 348; Band 18, S. 1816.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_471" href="#FNanchor_471" class="label">[471]</a>
+Vid. op. cit. supra, Band 19, S. 348.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_472" href="#FNanchor_472" class="label">[472]</a>
+Comptes rendus, Tome 107, p. 772; Hoppe-Seyler’s Handbuch
+der Physiologisch- und Pathologisch-Chemischen Analyse, S. 479.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_539"></a>[Pg 539]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_473" href="#FNanchor_473" class="label">[473]</a>
+Proceedings of the Society for the Promotion of Agricultural Science, 1888, p. 13.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_474" href="#FNanchor_474" class="label">[474]</a>
+Journal of Physiology, Vol. 11, p. 459.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_475" href="#FNanchor_475" class="label">[475]</a>
+Die Land wirtschaftlichen Versuchs-Stationen, Band 31, S. 131.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_476" href="#FNanchor_476" class="label">[476]</a>
+Sixth Annual Report of the Wisconsin Agricultural Experiment Station, p. 64.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_477" href="#FNanchor_477" class="label">[477]</a>
+Bulletin No. 46, Division of Chemistry, U. S. Department of Agriculture, p. 36.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_478" href="#FNanchor_478" class="label">[478]</a>
+Zeitschrift für Biologie, Band 33, S. 43.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_479" href="#FNanchor_479" class="label">[479]</a>
+Journal für praktische Chemie, {2}, Band 15, S. 329.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_480" href="#FNanchor_480" class="label">[480]</a>
+Vid. op. cit. 79, Band 33, {Neue Folge, 15}, S. 55.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_481" href="#FNanchor_481" class="label">[481]</a>
+Stenberg; Zeitschrift für physiologische Chemie, Band 13, S. 138.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_482" href="#FNanchor_482" class="label">[482]</a>
+Vid. op. cit. supra, S. 137.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_483" href="#FNanchor_483" class="label">[483]</a>
+Vid. op. cit. supra, S. 160.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_484" href="#FNanchor_484" class="label">[484]</a>
+Journal of the American Chemical Society, Vol. 15, p. 644.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_485" href="#FNanchor_485" class="label">[485]</a>
+Handbuch der Physiologisch- und Pathologisch-Chemischen
+Analyse, S. 285. (Read, Makris instead of Makeris.)</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_486" href="#FNanchor_486" class="label">[486]</a>
+Zeitschrift für Biologie, Band 23, S. 64.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_487" href="#FNanchor_487" class="label">[487]</a>
+Bulletin de la Société Chimique de Paris, 3ᵉ Série, Tome 11, p. 152.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_488" href="#FNanchor_488" class="label">[488]</a>
+Vid. op. cit. 86, S. 487.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_489" href="#FNanchor_489" class="label">[489]</a>
+Zeitschrift für Nahrungsmittel-Untersuchung, Band 10, S. 104.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_490" href="#FNanchor_490" class="label">[490]</a>
+Zeitschrift für physiologische Chemie, Band 9, S. 445.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_491" href="#FNanchor_491" class="label">[491]</a>
+American Chemical Journal, Vol. 6, p. 289.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_492" href="#FNanchor_492" class="label">[492]</a>
+Journal of the American Chemical Society, Vol. 18, p. 428.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_493" href="#FNanchor_493" class="label">[493]</a>
+Journal de Pharmacie et de Chimie, 6e Série, Tome 4, p. 65.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_494" href="#FNanchor_494" class="label">[494]</a>
+Contribution à l’Étude des Lactoses, Thèse pour le diplôme supérieure
+de Pharmacie, Paris, 1892. (Read Thibault instead of Thibonet.)</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_495" href="#FNanchor_495" class="label">[495]</a>
+Journal für praktische Chemie, Neue Folge, Band 15, S. 348.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_496" href="#FNanchor_496" class="label">[496]</a>
+Zeitschrift für angewandte Chemie, 1896, S. 72.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_497" href="#FNanchor_497" class="label">[497]</a>
+Chemisches Central-Blatt, 1892, Band 2, S. 1028.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_498" href="#FNanchor_498" class="label">[498]</a>
+Vid. op. cit. supra, Band 21, S. 753.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_499" href="#FNanchor_499" class="label">[499]</a>
+Vid. op. cit. 90, S. 86.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_500" href="#FNanchor_500" class="label">[500]</a>
+Bulletin No. 13, Division of Chemistry, U. S. Department of Agriculture, pp. 29 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_501" href="#FNanchor_501" class="label">[501]</a>
+Vid. op. cit. supra, pp. 73-75: Bulletin No. 46,
+Division of Chemistry, U. S. Department of Agriculture, p. 26.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_502" href="#FNanchor_502" class="label">[502]</a>
+Benedikt and Lewkowitsch; Oils, Fats and Waxes, p. 490.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_503" href="#FNanchor_503" class="label">[503]</a>
+Forsuchungs-Berichte über Lebensmittel, 1895, Band 2, S. 424;
+Chemiker-Zeitung Repertorium, 1896, Band 20, S. 15.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_504" href="#FNanchor_504" class="label">[504]</a>
+Revue Internationale des Falsifications, Mai, 1893, p. 157.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_505" href="#FNanchor_505" class="label">[505]</a>
+Chemiker-Zeitung, 1893, Band 17, S. 468.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_506" href="#FNanchor_506" class="label">[506]</a>
+Zeitschrift für angewandte Chemie, 1896, S. 177.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_507" href="#FNanchor_507" class="label">[507]</a>
+Vid. op. cit. 90, Aug. 26, 1894, S. 219; Le Stazioni
+Sperimentali Agrarie Italiane, 1893, pp. 25-77.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_540"></a>[Pg 540]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_508" href="#FNanchor_508" class="label">[508]</a>
+Farmers’ Bulletin No. 12, U. S. Department of Agriculture.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_509" href="#FNanchor_509" class="label">[509]</a>
+Bulletin de l’Association Belge des Chimistes, Tome 9, p. 279.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_510" href="#FNanchor_510" class="label">[510]</a>
+Vid. op. cit. 101, p. 26.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_511" href="#FNanchor_511" class="label">[511]</a>
+Vid. op. cit. supra, p. 27: Chemical News, Vol. 55, p. 49.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_512" href="#FNanchor_512" class="label">[512]</a>
+Vid. op. cit. 111, p. 28.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_513" href="#FNanchor_513" class="label">[513]</a>
+Vid. op. et. loc. cit. supra.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_514" href="#FNanchor_514" class="label">[514]</a>
+Russell; Dairy Bacteriology.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_515" href="#FNanchor_515" class="label">[515]</a>
+Woll; Dairy Calendar, p. 223.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_516" href="#FNanchor_516" class="label">[516]</a>
+Van Slyke; Bulletin 82, New Series, New York Agricultural Experiment Station, p. 654.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_517" href="#FNanchor_517" class="label">[517]</a>
+Babcock; Twelfth Annual Report Wisconsin Agricultural Experiment Station, p. 133.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_518" href="#FNanchor_518" class="label">[518]</a>
+Woll; Dairy Calendar, 1895, p. 220.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_519" href="#FNanchor_519" class="label">[519]</a>
+Bulletin No. 46, Division of Chemistry, U. S. Department of Agriculture, p. 37.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_520" href="#FNanchor_520" class="label">[520]</a>
+Landwirtschaftliches Jahrbuch, 1872, part 1.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_521" href="#FNanchor_521" class="label">[521]</a>
+Molkerei Zeitung, 1893, Nos. 20, 22.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_522" href="#FNanchor_522" class="label">[522]</a>
+This work, Vol. 2, p. 204.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_523" href="#FNanchor_523" class="label">[523]</a>
+Vid. op. cit. 120, p. 24.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_524" href="#FNanchor_524" class="label">[524]</a>
+Milch Zeitung, 1895, Band 24, S. 729: Chemiker-Zeitung Repertorium, Band 19, S. 372.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_525" href="#FNanchor_525" class="label">[525]</a>
+Chemiker-Zeitung, 1895, S. 554.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_526" href="#FNanchor_526" class="label">[526]</a>
+Zeitschrift für analytische Chemie, Band 35, S. 497.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_527" href="#FNanchor_527" class="label">[527]</a>
+Vid. op. cit. supra, S. 499.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_528" href="#FNanchor_528" class="label">[528]</a>
+Vid. op. cit. supra, S. 502.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_529" href="#FNanchor_529" class="label">[529]</a>
+Bulletin No. 13, Division of Chemistry, U. S. Department of Agriculture, pp. 118, 293.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_530" href="#FNanchor_530" class="label">[530]</a>
+This work, Vol. 2, p. 204.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_531" href="#FNanchor_531" class="label">[531]</a>
+Pflüger’s Archiv, Band 56, S. 558.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_532" href="#FNanchor_532" class="label">[532]</a>
+Hoppe-Seyler’s Zeitschrift für physiologische Chemie, Band 22, S. 213.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_533" href="#FNanchor_533" class="label">[533]</a>
+Bulletin de la Société Chimique de Paris, Tomes 15-16, p. 1126.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_534" href="#FNanchor_534" class="label">[534]</a>
+American Chemical Journal, Vol. 8, p. 200: Bulletin 13,
+Division of Chemistry, U. S. Department of Agriculture, p. 120.</p>
+</div>
+</div>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum"><a id="Page_541"></a>[Pg 541]</span></p>
+<h2 class="nobreak">PART SEVENTH.<br>
+<span class="h_subtitle">MISCELLANEOUS AGRICULTURAL PRODUCTS.</span></h2>
+</div>
+
+<p><b>527. Classification.</b>—In the preceding parts have been set forth
+the fundamental principles underlying the conduct of agricultural
+analysis and a résumé of the best practice of the art. The analyst, as
+a rule, will seldom be required to undertake investigations which are
+unnoticed in the preceding pages. Cases will arise, however, in which
+problems are presented which can not be solved by the rules already
+elucidated. In respect of the great classes of agricultural bodies,
+it will be observed that dairy products have already received special
+mention. In respect of foods and fodders in general, it is evident that
+they are chiefly composed of moisture, ash, carbohydrates, oils and
+proteid matters. The methods of identifying, separating and estimating
+these constituents have been fully set forth. It is not necessary,
+therefore, to study in this part the analytical processes which are
+applicable to cereals, cattle foods and other food products, further
+than is necessary to present in the most important cases a working
+résumé of principles and methods. There remain, however, certain
+products of importance which require some special modifications of
+treatment, and it is to these that the present part will be chiefly
+devoted. Among these are found tobacco, tea and coffee, fruits,
+fermented and distilled drinks and certain animal products. It is
+evident that an enumeration of all agricultural products, with a
+description of their methods of examination, would be impracticable in
+the available space and undesirable by reason of the repetition which
+would be required. In each case the analyst, in possession of the
+methods described, will be able to adapt the means at his disposal to
+the desired purpose to better advantage than any rigid directions could
+possibly secure.
+<span class="pagenum"><a id="Page_542"></a>[Pg 542]</span></p>
+
+<p>In respect of the analytical methods of determining the nutritive
+value of foods, they may be divided into chemical and physiological.
+The chemical methods embrace the thermal and artificial digestion
+investigations, and the physiological include those which are carried
+out with the help of the animal organisms. In the latter case the
+digestive process is checked by the analysis of the foods before
+ingestion and of the excreta of all kinds during and after digestion.</p>
+
+<p>It is evident that a detailed description of this method should be
+looked for in works devoted to physiological chemistry.</p>
+
+<h3>CEREALS AND CEREAL FOODS.</h3>
+
+<p><b>528. General Analysis.</b>—The cereals are prepared for analysis
+by grinding until the fragments pass a sieve having circular
+perforations half a millimeter in diameter. The moisture, ash, ether
+extract, proteids and carbohydrates are determined by some one of the
+processes already described in detail. In this country the methods
+of the Association of Official Agricultural Chemists are generally
+followed.<a id="FNanchor_535" href="#Footnote_535" class="fnanchor">[535]</a>
+For convenience these methods are summarized below.</p>
+
+<p><i>Moisture.</i>—Dry from two to three grams of the fine-ground sample
+for five hours, at the temperature of boiling water, in a current of
+dry hydrogen. If the substance be held in a glass vessel, the latter
+should not be in contact with the boiling water.</p>
+
+<p><i>Ash.</i>—Char from two to three grams of the sample and burn to
+whiteness at the lowest possible red heat. If a white ash can not be
+obtained in this manner, exhaust the charred mass with water, collect
+the insoluble residue on a filter, burn it, add this ash to the residue
+from the evaporation of the aqueous extract and heat the whole to low
+redness until the ash is white.</p>
+
+<p><i>Ether Extract.</i>—Pure ether is prepared by washing the commercial
+article four or five times with water to free it of the chief part
+of the alcohol it contains. The residual water is mostly removed by
+treating the liquid with caustic soda or potash. Any residual alcohol
+or water is finally removed by the action of metallic sodium. The ether
+thus prepared is stoppered, after the evolution of hydrogen has ceased,
+<span class="pagenum"><a id="Page_543"></a>[Pg 543]</span>
+and is kept over metallic sodium. Immediately before use it should be
+distilled out of contact with moist air.</p>
+
+<p>The residue from the determination of moisture, as described above, is
+extracted in an appropriate apparatus (<b><a href="#P_39">39</a></b>) with the pure ether
+for sixteen hours. The extract is dried to constant weight. The weight
+may be checked by drying and weighing the extraction tube and its
+contents before and after the operation.</p>
+
+<p><i>Crude Proteids.</i>—Proceed as in the method of determining
+nitrogen in the absence of nitrates and multiply the weight of nitrogen
+obtained by 6.25. This factor is a general one, but should not be
+rigidly applied. In each instance, according to the nature of the
+cereal, the appropriate factor, pointed out in paragraph <b><a href="#P_407">407</a></b>
+should be used, and the factor 6.25 be applied only in those cases
+where a special factor is not given. The factors for the common cereals
+are wheat 5.70, rye 5.62, oats 6.06, maize 6.22, barley 5.82 and flaxseed 5.62.</p>
+
+<p>For separating the proteid matters consult paragraphs <b><a href="#P_392">392-410</a></b>.
+In the case of wheat the methods of Teller may be consulted.<a id="FNanchor_536" href="#Footnote_536" class="fnanchor">[536]</a></p>
+
+<p><i>Amid Nitrogen.</i>—The albuminoid nitrogen is determined as
+directed in paragraph <b><a href="#P_203">203</a></b> of volume II. The difference between
+this number and that representing the total nitrogen gives the nitrogen
+as amids.</p>
+
+<p><i>Fiber and Carbohydrates.</i>—The methods of analysis are described
+in detail in Part Third.</p>
+
+<p><b>529. Bread.</b>—In general, the same processes are followed in
+bread analysis as are used with cereals and flours. In addition to
+the regular analytical processes, breads are to be examined for
+adulterants, bleaching and coloring matters, and for the purpose of
+determining the changes which have taken place in their nutrient
+constituents in the processes of fermentation and cooking.</p>
+
+<p><i>Temperature of Baking.</i>—The interior of a loaf during the
+process of baking does not attain the high temperature commonly
+supposed. This temperature is rarely found to be more than one degree
+above the boiling point of water.<a id="FNanchor_537" href="#Footnote_537" class="fnanchor">[537]</a>
+In biscuits and other thin cakes, which become practically dry and
+which by reason of their thinness are the more readily penetrated by
+heat, the temperature may go as high as 110°.</p>
+
+<p><i>Soluble Extract.</i>—The quantity of matters both in flour and
+bread, soluble in cold water, is determined by extraction in the usual
+<span class="pagenum"><a id="Page_544"></a>[Pg 544]</span>
+way and drying the extract. Soluble albuminoids, sugars and mineral
+salts are extracted by this process. When possible, the operation should
+be conducted both on the bread and the flour from which it is made.</p>
+
+<p><i>Color.</i>—In baker’s parlance is found an apparent contradiction
+of terms, since it speaks of bread with “no color” when the loaf is
+dark brown, while a white loaf is said to have a high color. An ideal
+color for the interior of a loaf is a light cream tint, which is
+more desirable than a pure white.<a id="FNanchor_538" href="#Footnote_538" class="fnanchor">[538]</a>
+The texture, odor and flavor of the loaf are also to be considered, but
+these are properties of more importance to the technical expert than to
+the analyst.</p>
+
+<p><i>Quantity of Water.</i>—It is not possible to set a rule of
+limitation in respect of the quantity of water a bread should hold. For
+full loaves, perhaps forty per cent is not too high a maximum, while
+some authors put it as low as thirty-four per cent. Some flours are
+capable of holding more water than others, and the loaf should have
+just enough water to impart to the slice of bread the requisite degree
+of softness and the proper texture. Most breads will have a content of
+water ranging from thirty to forty per cent. In biscuits and other thin
+cakes the moisture is much less in quantity.</p>
+
+<p><i>Acidity.</i>—The acidity of both bread and flour is determined by
+shaking ten grams of the sample with 200 cubic centimeters of distilled
+water for fifteen minutes, pouring the mass on a filter and titrating
+an aliquot part of the filtrate with tenth-normal alkali. The acidity
+is reckoned as lactic acid in the case of breads raised by fermentation.</p>
+
+<p><i>Nature of Nitrogenous Compounds.</i>—The methods of investigation
+are described in paragraphs <b><a href="#P_392">392-410</a></b>.</p>
+
+<p><b>530. Determination of Alum in Bread.</b>—The presence of alum in
+bread may be detected by means of logwood. Five grams of fresh logwood
+chips are digested with 100 cubic centimeters of amyl alcohol. One
+cubic centimeter of this decoction and the same quantity of a saturated
+solution of ammonium carbonate are mixed with ten grams of flour and
+an equal quantity of water. With pure flour, a slight pink tint is
+<span class="pagenum"><a id="Page_545"></a>[Pg 545]</span>
+produced. In the presence of alum the color changes to a lavender or
+blue, which is persistent on heating.</p>
+
+<p>The test may be varied by diluting five cubic centimeters of the
+reagents mentioned with ninety cubic centimeters of water and pouring
+the mixture over ten grams of the crumbled bread. After standing for
+five minutes, any residual liquid is poured off and the residue, washed
+once with a little water, is dried in a steam bath, when the blue color
+is developed if alum be present.<a id="FNanchor_539" href="#Footnote_539" class="fnanchor">[539]</a></p>
+
+<p><b>531. Chemical Changes Produced by Baking.</b>—Changes of a chemical
+nature, produced in bread by baking, are found chiefly in modifications
+of the starch and proteids. The starch is partly converted into dextrin
+and the albumins are coagulated. The changes in digestion coefficient
+are determined by the methods which follow. The fermentations which
+precede the baking are due to the usual decompositions of the
+carbohydrates under the influence of yeast germs.</p>
+
+<h3>FODDERS, GRASSES<br> AND ENSILAGE.</h3>
+
+<p><b>532. General Principles.</b>—The analyst, in examining the fibrous
+foods of cattle, is expected to determine moisture, ash, fiber and
+other carbohydrates, ether extract and albuminoid and amid nitrogen. If
+a more exhaustive study be required, the sugar and starch are separated
+from the other non-nitrogenous matters, the carbohydrate bodies
+yielding furfuraldehyd separately determined and the ash subjected to
+a quantitive analysis. The processes are conducted in harmony with the
+principles and methods of procedure fully set forth in the preceding pages.</p>
+
+<p>Green fodders and grasses are easily dried and sampled by comminution
+in the shredder described on <a href="#Page_9">page 9</a>, and roots
+by that shown on <a href="#Page_10">page 10</a>. The moisture is
+determined by drying a small sample of the shredded mass, while the
+rest of it is dried, first at about 60° and finally at 100°, or a
+little above, ground to a fine powder and subjected to analysis by
+methods already described. The food values as obtained by analysis
+should be compared, when possible, with those secured by natural and
+artificial digestion.
+<span class="pagenum"><a id="Page_546"></a>[Pg 546]</span></p>
+
+<p>Ensilage is shredded and analyzed in precisely the same way, but in
+drying, the content of volatile acids formed during fermentation must
+be considered. In other words, the loss on drying ensilage at 100°, or
+slightly above, is due not only to the escape of water but also to the
+volatilization of the acetic acid, which is one of the final products
+of fermentation which the mass undergoes in the silo.</p>
+
+<p><b>533. Organic Acids in Ensilage.</b>—In the examination of ensilage,
+the organic acids which are present may be determined by the processes
+described in following paragraphs. The acetic acid, formed chiefly
+by fermentation, is conveniently determined by the method given for
+tobacco further on. Lactic acid is detected and estimated by expressing
+the juice from a sample of ensilage, removing the acetic acid by
+distillation, repeated once or twice, and treating the filtered residue
+with zinc carbonate in excess, filtering and determining the zinc
+lactate in the filtrate. The zinc is determined by the method described
+for evaporated apples and the lactic acid calculated from the weight of
+zinc found. Crystallized zinc lactate contains 18.18 per cent of water
+and 27.27 per cent of zinc oxid.<a id="FNanchor_540" href="#Footnote_540" class="fnanchor">[540]</a></p>
+
+<p><b>534. Changes due to Fermentation in the Silo.</b>—Silage differs
+from green fodder in having less starch and sugar, more acetic and
+lactic acids and alcohol and a higher proportion of amid to albuminoid
+nitrogen.<a id="FNanchor_541" href="#Footnote_541" class="fnanchor">[541]</a>
+There is also a considerable loss of nitrogenous substances in
+ensilage, due probably to their conversion into ammonium acetate, which
+is lost on drying.</p>
+
+<p><b>535. Alcohol in Ensilage.</b>—The fermentation which takes place
+in the silo is not wholly of an alcoholic nature, as the development
+of lactic acid, noted above, clearly indicates. The alcohol which
+is formed may escape and but small quantities can be detected in
+the ripened product. So small is this quantity of alcohol that it
+appears to be useless to try to secure a quantitive estimation of it.
+Qualitively, it may be detected by collecting it in a distillate, which
+is neutralized or made slightly alkaline with soda or potash lye and
+redistilled. The greater part of the alcohol will be found in the first
+few cubic centimeters, which are made alkaline with potash lye and as
+<span class="pagenum"><a id="Page_547"></a>[Pg 547]</span>
+much iodin added as can be without giving a red tint to the solution.
+Any alcohol which is present will soon separate as iodoform.</p>
+
+<p><b>536. Comparative Values of Fodder and Ensilage.</b>—In judging of
+the comparative values of green and dry fodders for feeding purposes,
+it is necessary to secure representative samples in the green, quickly
+dried and ensilaged condition. It is quite certain that the greater
+part of the sugar contained in green fodders is lost both by natural
+curing and by placing in a silo. When well cured by the usual processes
+there is but little loss of nitrogenous matters, but in the silo this
+loss is of considerable magnitude, amounting in some instances to as
+much as thirty per cent.</p>
+
+<p>The ideal way of preparing green fodders in order to preserve the
+maximum food value efficiently, is to shred them and dry rapidly by
+artificial heat, or in the sunlight, until they are in a condition
+which insures freedom from fermentation. In this condition, when placed
+in bales, under heavy pressure, the food constituents are preserved in
+the highest available form. The immense sugar content of the stalks of
+maize and sorghum could be preserved in this way almost indefinitely.</p>
+
+<h3>FLESH PRODUCTS.</h3>
+
+<p><b>537. Names Of Meats.</b>—The parts of the animal from which the
+meats are taken have received distinctive names, which serve to
+designate the parts of the carcass offered for sale. These names are
+not invariable and naturally are quite different in many markets. In
+this country there is some degree of uniformity among butchers in
+naming the meats from different parts. The names in scientific use
+for the parts of mutton, beef and pork are found in the accompanying
+illustrations.<a id="FNanchor_542" href="#Footnote_542" class="fnanchor">[542]</a></p>
+
+<p><b>538. Sampling.</b>—When possible the whole animal should constitute
+the sample. The relative weights of blood, intestinal organs, hide,
+hoofs, horns, bones and edible flesh are determined as accurately as
+possible. The general method of preparing samples of animal products is
+given in paragraph <b><a href="#P_5">5</a></b>.
+<span class="pagenum"><a id="Page_548"></a>[Pg 548]</span></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_114" src="images/fig114.jpg" alt="" width="600" height="395" >
+    <p class="center">Fig. 114.</p>
+    <img id="FIG_115" src="images/fig115.jpg" alt="" width="600" height="376" >
+    <p class="center">Fig. 115.</p>
+    <img id="FIG_116" src="images/fig116.jpg" alt="" width="600" height="372" >
+    <p class="center">Fig. 116.</p>
+    <p class="f105 spb1">Names of Cuts of Meat.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_549"></a>[Pg 549]</span>
+The method of sampling employed by Atwater and Woods is essentially
+that just noted.<a id="FNanchor_543" href="#Footnote_543" class="fnanchor">[543]</a>
+The sample, as received at the laboratory, is weighed, the flesh
+(edible portion) is then separated from the refuse (skin, bones etc.)
+and both portions weighed. There is always a slight loss in the
+separation, evidently due to evaporation and to small fragments of
+the tissues that adhere to the hands and to the implements used in
+preparing the sample. The perfect separation of the flesh from the
+other tissues is difficult, but the loss resulting from this is small.
+In sampling the material for analysis, it is finely chopped, either in
+a tray or in a sausage cutter, and in each case is well mixed.</p>
+
+<p><b>539. Methods of Analysis.</b>—The general methods for the analyses
+of food products are applicable to meats and animal products in
+general. In the separation of the nitrogenous constituents the methods
+described in paragraphs <b><a href="#P_411">411-414</a></b> are followed. It is
+not safe to estimate as proteids the total nitrogen multiplied by 6.25, since the
+flesh bases have much higher percentages of nitrogen than are found
+in proteid matters. As indicated in paragraph <b><a href="#P_280">280</a></b> the
+complete extraction of dried meats by ether is difficult of accomplishment.
+After a few hours it may be assumed that the total extract will
+represent the fat, although additional soluble matters are obtained
+by continuing the process. The heat producing power may be calculated
+from the analytical data secured. The methods which have been described
+in the preceding pages will be found sufficient for guidance in the
+examination of animal products, and the analyst will find them, when
+modified to suit particular cases, adapted to the isolation and
+estimation of proximate food principles.</p>
+
+<p>The methods of analyses followed by Atwater and Woods are given
+below:<a id="FNanchor_544" href="#Footnote_544" class="fnanchor">[544]</a></p>
+
+<p><i>Water and Water-Free Substance.</i>—The drying is done in ordinary
+water ovens at a temperature of nominally 100°, but actually at 96° and
+98°. For each analysis of animal tissues (flesh) one or more samples of
+from fifty to one hundred grams of the freshly chopped substance are
+weighed on a small plate, heated for from twenty-four to forty-eight
+<span class="pagenum"><a id="Page_550"></a>[Pg 550]</span>
+hours, cooled, allowed to stand in the open air for about twenty-four
+hours, weighed, ground, sifted through a sieve with circular holes
+one-half millimeter in diameter, bottled and set aside for analysis.
+In case of fat samples which cannot be worked through so fine a sieve,
+either a coarser sieve is used or the substance crushed as finely as
+practicable and bottled without sifting.</p>
+
+<p>For the complete desiccation, about two grams of material are dried for
+three hours. It is extremely difficult to get an absolutely constant
+weight, though it is found that this is in most cases approximately
+attained in four hours.</p>
+
+<p><i>Nitrogen, Protein, Albuminoids etc.</i>—The nitrogen is determined
+in the partly dried substance by the method of Kjeldahl. The protein
+is calculated by multiplying the percentage of nitrogen by 6.25.
+The nitrogenous matters in meats and fish, <i>i. e.</i>, in the
+materials which have practically no carbohydrates, are also estimated
+by subtracting the sum of ether extract and ash from the water-free
+substance, or the sum of water, ether extract and ash from the fresh
+substance, the remainder being taken as proteids, albuminoids etc.,
+by difference. While this is not an absolutely correct measure of the
+total nitrogenous matter, it is doubtless more nearly so than the
+product of the nitrogen multiplied by 6.25.</p>
+
+<p><i>Fat (Ether Extract).</i>—The fat is extracted with ether in
+the usual manner. The point at which the extraction is complete is
+not always easy to determine. For the most part, the extraction is
+continued for such time as experience indicates to be sufficient, and
+then the flask is replaced by another and the extraction repeated until
+the new flask shows no increase in weight.</p>
+
+<p>According to experience, the fat of many animal tissues is much more
+difficult to extract than that of most vegetable substances. In
+general, the greater the percentage of fat in a substance the more
+difficult is the removal of the last traces. Dried flesh is frequently
+so hard that the fineness of the material to be extracted seems to be a
+very important matter.</p>
+
+<p><i>Ash.</i>—Ash is determined by the method recommended by the
+Association of Official Agricultural Chemists.
+<span class="pagenum"><a id="Page_551"></a>[Pg 551]</span></p>
+
+<p><i>Food Value—Potential Energy.</i>—The food materials are not
+necessarily burned in the calorimeter, but the fuel value of a pound of
+each of the foods, as given in the tables, is obtained by multiplying
+the number of hundredths of a pound of protein and of carbohydrates by
+18.6 and the number of hundredths of a pound of fat by 42.2, and taking
+the sum of these three products as the number of calories of potential
+energy in the materials.</p>
+
+<p>More reliable results are obtained by using the factors obtained by
+Stohmann; <i>viz.</i>, 5731 calories for proteids, 9500 calories for
+common glycerids, 9231 calories for butter fat, 3746 calories for
+pentose sugars, 3749 calories for dextrose and levulose and 3953
+calories for sucrose and milk sugar.<a id="FNanchor_545" href="#Footnote_545" class="fnanchor">[545]</a></p>
+
+<p><b>540. Further Examination of Nitrogenous Bodies.</b>—It is evident
+that both of the methods proposed above for the examination of the
+nitrogenous constituents of meats are unreliable. If the total nitrogen
+be determined and multiplied by 6.25 the product does not by any means
+represent the true quantity of nitrogenous matter since the flesh bases
+contain in some instances more than twenty-five per cent of nitrogen.</p>
+
+<p>If, on the other hand, the water, ash and fat in a meat sample be
+determined and the sum of their per cents be subtracted from 100, the
+difference represents the nitrogenous bodies plus all undetermined
+matters and errors of analysis. The assumption that meats are free
+of carbohydrates is not tenable since glycogen is constantly found
+therein and in horse flesh in comparatively large amounts. In a
+thoroughly scientific analysis of meats, the nitrogenous bodies should
+be separated and determined by groups, according to the principles
+developed in paragraphs <b><a href="#P_411">411-414</a></b>. This process requires
+a great amount of analytical work and in general it will be sufficient to make
+a cold water extract to secure the flesh bases and a hot water extract
+to secure the gelatin. The nitrogen is then determined in each of
+these portions separately. The nitrogen in the cold water extract is
+multiplied by four, in the hot water extract by six and in the residue
+by 6.25. The sum of these products represents approximately the total
+nitrogenous matter in the sample.
+<span class="pagenum"><a id="Page_552"></a>[Pg 552]</span></p>
+
+<p>Aqueous extracts containing nitrogen are easily prepared for moist
+combustion by placing them in the digestion flasks, connecting the
+latter with the vacuum service and evaporating the contents of the
+flask nearly to dryness. The sulfuric acid is then added and the
+nitrogen converted into ammonia and determined in the usual manner.</p>
+
+<p><b>541. Fractional Analysis of Meats.</b>—A better idea of the
+composition of a meat is obtained by separating its constituents into
+several groups by the action of different solvents. This method has
+been elaborated by Knorr.<a id="FNanchor_546" href="#Footnote_546" class="fnanchor">[546]</a></p>
+
+<p>The separation of the meats in edible portion and waste and the
+determination of moisture and fat are conducted as already described.
+The residue from the fat extraction is exhausted with alcohol, and
+in the extract are found the nitrogenous bases kreatin, kreatinin,
+sarkin and xanthin, and urea, lactic, butyric, acetic and formic acids,
+glycogen and inosit. In the residue from the alcohol extraction, the
+proteid nitrogen is determined in a separate sample.</p>
+
+<p>A separate portion of the sample is ground to a fine paste and
+repeatedly rubbed up with cold water, which is poured through a tared
+filter. When the extraction is complete, the filter and its contents
+are dried and the dry residue determined. This residue represents
+the nitrogenous constituents of the muscle fibers and their sheaths
+together with any other bodies insoluble in cold water. The filtrate
+from the cold water extraction is heated to boiling to precipitate
+the albuminous matters which are collected, dried and weighed, or the
+nitrogen therein determined and the albuminous matters calculated by
+multiplying by the usual factor. The filtrate from the coagulated
+albuminous bodies is evaporated to dryness and weighed. It consists
+essentially of the same materials as the alcoholic extract mentioned
+above. The ash and nitrogen in the aqueous extract are also determined.</p>
+
+<p>The mean content of the edible parts of common meats, expressed as per
+cents in groups as mentioned, follow:
+<span class="pagenum"><a id="Page_553"></a>[Pg 553]</span></p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdr" colspan="2">Per cent.</td>
+   </tr><tr>
+      <td class="tdl">Water</td>
+      <td class="tdr">73.11</td>
+   </tr><tr>
+      <td class="tdl">Ash</td>
+      <td class="tdr">1.18</td>
+   </tr><tr>
+      <td class="tdl">Total soluble matter</td>
+      <td class="tdr">26.89</td>
+   </tr><tr>
+      <td class="tdl">Phosphoric acid</td>
+      <td class="tdr">0.49</td>
+   </tr><tr>
+      <td class="tdr" colspan="2">&nbsp;<br>Per cent.</td>
+   </tr><tr>
+      <td class="tdl">Proteids insoluble in cold water</td>
+      <td class="tdr">13.76</td>
+   </tr><tr>
+      <td class="tdl_ws1 bb">Of which coagulable by heat</td>
+      <td class="tdr bb">2.24</td>
+   </tr><tr>
+      <td class="tdl bb">Cold water extract</td>
+      <td class="tdr bb">3.56</td>
+   </tr><tr>
+      <td class="tdl">Ash in water extract</td>
+      <td class="tdr">1.09</td>
+   </tr><tr>
+      <td class="tdl_ws1">Of which phosphoric acid</td>
+      <td class="tdr">0.38</td>
+   </tr><tr>
+      <td class="tdr" colspan="2">&nbsp;<br>Per cent.</td>
+   </tr><tr>
+      <td class="tdl">Fat</td>
+      <td class="tdr">4.93</td>
+   </tr><tr>
+      <td class="tdl">Alcohol extract</td>
+      <td class="tdr">3.03</td>
+   </tr><tr>
+      <td class="tdl">Proteids in residue from alcohol<span class="ws3">&nbsp;</span></td>
+      <td class="tdr">17.88</td>
+   </tr><tr>
+      <td class="tdl">Total nitrogen in sample</td>
+      <td class="tdr">3.37</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>542. Estimation of Starch in Sausages.</b>—Starchy substances are
+sometimes added to sausages for the purpose of increasing their weight.
+The presence of starch in a sausage is easily detected by iodin. The
+quantity may be determined by the following process:<a id="FNanchor_547" href="#Footnote_547" class="fnanchor">[547]</a></p>
+
+<p>The principle of the process is based upon the observation that while
+starch is easily soluble in an aqueous solution of the alkalies, it
+is insoluble in an alcoholic solution thereof. The chief constituents
+of meat, <i>viz.</i>, fat and proteid matters, on the other hand,
+are readily soluble in an alcoholic solution of potash or soda. This
+renders the separation of the starch easy. The sample is warmed on a
+water bath with a considerable excess of an eight per cent solution of
+potassium hydroxid in alcohol whereby the fat and flesh are quickly
+dissolved. The starch and other carbohydrate bodies, remain in an
+undissolved state. In order to prevent the gelatinizing of the soap
+which is formed, the mass is diluted with warm alcohol, the insoluble
+residue collected upon a filter and washed with alcohol until the
+alkaline reaction disappears. The residue is then treated with aqueous
+potassium hydroxid solution, whereby the starch is brought into
+solution and, after filtration, is treated with alcohol until it is
+all precipitated. The precipitated starch is collected upon a filter,
+washed with alcohol and finally with ether, dried and weighed. Starch
+<span class="pagenum"><a id="Page_554"></a>[Pg 554]</span>
+prepared in this way contains a considerable quantity of potash, the
+amount of which can be determined by incineration. In order to avoid
+this trouble, the starch, after separation in the first instance
+as above mentioned and solution in aqueous potassium hydroxid,
+is precipitated on the addition of enough acetic to render the
+solution slightly acid. The precipitated starch, in this instance,
+is practically free of potash, since potassium acetate is soluble in
+alcohol.</p>
+
+<p><b>543. Detection of Horse Flesh.</b>—Since horse flesh has become
+an important article of human food and is often sold as beef and
+sausage, a method of distinguishing it is desirable. The comparative
+anatomist is able to detect horse flesh when accompanied by its bones,
+or in portions sufficiently large for the identification of muscular
+characteristics. It is well known that horse flesh contains a much
+higher percentage of glycogen than is found in other edible meats.
+Niebel has based a method of detecting horse flesh upon this fact, the
+glycogen being converted into dextrose and determined in the usual way.
+Whenever the percentage of reducing sugars in the dry fat-free flesh
+exceeds one per cent, Niebel infers that the sample under examination
+is horse flesh.<a id="FNanchor_548" href="#Footnote_548" class="fnanchor">[548]</a></p>
+
+<p>The reaction for horse flesh, proposed by Bräutigam and Edelmann, is
+preferred by Baumert. In this test about fifty grams of the flesh are
+boiled for an hour with 200 cubic centimeters of water, the filtered
+bouillon evaporated to about half its volume, treated with dilute
+nitric acid and the clear filtrate covered with iodin water. Horse
+flesh, by reason of its high glycogen content, produces a burgundy
+red zone at the points of contact of the two liquids. In the case of
+sausages, if starch have been added, a blue zone is produced, and if
+dextrin be present, a red zone, both of which obscure the glycogen
+reaction. The starch is easily removed by treating the bouillon with
+glacial acetic acid. No method is at present known for separating
+dextrin from glycogen. The detection of horse flesh is a matter of
+considerable importance to agriculture as well as to the consumers,
+especially of sausages. A considerable quantity of horse flesh is
+annually sent to the market, little of which presumably is sold under
+<span class="pagenum"><a id="Page_555"></a>[Pg 555]</span>
+its own name. As a cheap substitute for beef and pork in sausages, its
+use must be regarded as fraudulent, although no objection can be urged
+against its sale when offered under its own name.<a id="FNanchor_549" href="#Footnote_549" class="fnanchor">[549]</a></p>
+
+<h3>METHODS OF DIGESTION.</h3>
+
+<p><b>544. Artificial Digestion.</b>—The nutrient values of cereals and
+other foods are determined both by chemical analysis and by digestion
+experiments. The heat forming properties of foods are disclosed by
+combustion in a calorimeter, but the quantity of heat produced is not
+in every case a guide to the ascertainment of the nutritive value. This
+is more certainly shown, especially in the case of proteid bodies, by
+the action of the natural digestive ferments.</p>
+
+<p>It is probable that the digestion, which is secured by the action of
+these ferments without the digestive organs, is not always the same as
+the natural process, but when the conditions which prevail in natural
+digestion are imitated as closely as possible the effects produced can
+be considered as approximately those of the alimentary canal in healthy
+action.</p>
+
+<p>Three classes of ferments are active in artificial digestion,
+<i>viz.</i>, amylolytic ferments, serving to hydrolyze starch and
+sugars and to convert them into dextrose, maltose and levulose,
+aliphalytic ferments, which decompose the glycerids and proteolytic
+ferments, which act on the nitrogenous constituents of foods. When
+these ferments are made to act on foods under proper conditions of
+acidity and temperature, artificial digestion ensues, and by the
+measurement of the extent of the action an approximate estimate of
+their digestibility can be secured. In artificial digestion, the
+temperature should be kept near that of the body, <i>viz.</i>, at about 40°.</p>
+
+<p>The soluble ferments which are active in the digestion of foods, as
+has been intimated, comprise three great classes. Among the first
+class, <i>viz.</i>, the amylolytic ferments, are included not only those
+which convert starch into dextrose, but also those which cause the
+hydrolysis of sugars in general. Among these may be mentioned ptyalin,
+invertase, trehalase, maltase, lactase, diastase, inulase, pectase and
+cyto-hydrolytic ferments which act upon the celluloses and other fibers.
+<span class="pagenum"><a id="Page_556"></a>[Pg 556]</span></p>
+
+<p>Among the aliphalytic ferments, in addition to those which act also
+upon proteid matter, may be mentioned a special one, lipase.</p>
+
+<p>In the third class of ferments are found pepsin, trypsin or pancreatin
+and papain.</p>
+
+<p>For the latest information in regard to the nature of the soluble
+ferments and their nomenclature, the work of Bourquelot may be
+consulted.<a id="FNanchor_550" href="#Footnote_550" class="fnanchor">[550]</a></p>
+
+<p><b>545. Amylytic Ferments.</b>—A very active ferment of this kind is
+found in the saliva. Saliva may be easily collected from school boys,
+who will be found willing to engage in its production if supplied with
+a chewing gum. A gum free of sugar is to be used, or if the chewing
+gum of commerce is employed, the saliva should not be collected until
+the sugar has disappeared. A dozen boys with vigorous chewing will
+soon provide a sufficient quantity of saliva for practical use. The
+amylolytic digestion is conducted in the apparatus hereinafter described
+for digestion with pepsin and pancreatin. The starch or sugar in fine
+powder is mixed with ten parts of water and one part of saliva and
+kept at about 37°.5 for a definite time. The product is then examined
+for starch, sucrose, maltose, dextrose, dextrin and levulose by the
+processes already described. In natural digestion the hydrolysis of the
+carbohydrates is not completed in the mouth. The action of the ferment
+is somewhat diminished in the stomach, but not perhaps until half an
+hour after eating. The dilute hydrochloric acid in the stomach, which
+accumulates some time after eating, is not active in this hydrolysis.
+On the contrary the amylolytic ferment of the saliva is somewhat
+enfeebled by the presence of an acid. The active principle of the
+saliva is ptyalin.</p>
+
+<p>The diastatic hydrolysis of starch has already been described
+(<b><a href="#P_179">179</a></b>). It is best secured at a somewhat
+higher temperature than that of the human stomach.</p>
+
+<p><b>546. Aliphalytic Ferments.</b>—In the hydrolysis of glycerids in
+the process of digestion the fat acids and glycerol are set free.
+Whether the glycerids be completely hydrolyzed before absorption is not
+definitely known. In certain cases where large quantities of oil have
+<span class="pagenum"><a id="Page_557"></a>[Pg 557]</span>
+been exhibited for remedial purposes, the fat acids and soaps have been
+found in spherical masses in the dejecta<a id="FNanchor_551" href="#Footnote_551" class="fnanchor">[551]</a>
+and have been mistaken for gall stones.</p>
+
+<p>The fat which enters the chyle appears to be mostly unchanged, except
+that it is emulsified.<a id="FNanchor_552" href="#Footnote_552" class="fnanchor">[552]</a>
+The aliphalytic ferment can be prepared from the fresh pancreas,
+preferably from animals that have not been fed for forty hours before
+killing. It is important to prepare the ferment entirely free of
+any trace of acid. The fresh glands are rubbed to a fine paste with
+powdered glass and extracted for four days with pure glycerol, to which
+one part of one per cent soda solution has been added. The filtered
+liquor contains aliphalytic, proteolytic and amylytic ferments, and is
+employed for saponification by shaking with the fat to form an emulsion
+and keeping the mixture, with occasional shaking, at a temperature of
+from 40° to 60°. The free acids can be titrated or separated from the
+unsaponified fats by solution in alcohol.<a id="FNanchor_553" href="#Footnote_553" class="fnanchor">[553]</a></p>
+
+<p>Heretofore it has not been possible to separate a pure aliphalytic
+ferment from any of the digestive glands. The digestion of carbohydrates
+and that of fats are intimately associated, and these two classes of
+foods seem to play nearly the same rôle in the animal economy.</p>
+
+<p>The aliphalytic ferments, prepared from the fresh pancreas, act also on
+the glucosids and other ester-like carbohydrate bodies. Since the fats
+may be regarded as ethers, the double action indicates the similarity
+of composition in the two classes of bodies.<a id="FNanchor_554" href="#Footnote_554" class="fnanchor">[554]</a>
+The aliphalytic ferments exist also in plants and have been isolated
+from rape seed.<a id="FNanchor_555" href="#Footnote_555" class="fnanchor">[555]</a></p>
+
+<p><b>547. Proteolytic Ferments.</b>—The most important process in
+artificial digestion is the one relating to the action of the ferments
+on proteid matters. The hydrolysis of fats and carbohydrates by natural
+ferments takes place best in an alkaline medium, while in the case of
+proteids when pepsin is used an acid medium is preferred. Since the
+acidity of the stomach is due chiefly to hydrochloric, that acid is
+employed in artificial digestion. The hydrolyte used is uniformly the
+natural ferment of the gastric secretions, <i>viz.</i>, pepsin; but
+this is often followed by the pancreatic ferment, (pancreatin, trypsin)
+<span class="pagenum"><a id="Page_558"></a>[Pg 558]</span>
+in an alkaline medium. During the digestion, the proteids are changed
+into peptones, and the measurement of this change determines the degree
+of digestion. The total proteid matter is determined in the sample,
+and after the digestion is completed, the soluble peptones are removed
+by washing and the residual insoluble proteid matter determined by
+moist combustion. The difference in the two determinations shows the
+quantity of proteid matter digested. The investigations of Kühn on the
+digestion of proteids may be profitably consulted.<a id="FNanchor_556" href="#Footnote_556" class="fnanchor">[556]</a>
+For a summary of digestion experiments in this country the résumé
+prepared by Gordon may be consulted.<a id="FNanchor_557" href="#Footnote_557" class="fnanchor">[557]</a>
+The method followed in this laboratory is fully described by Bigelow and
+Hamilton.<a id="FNanchor_558" href="#Footnote_558" class="fnanchor">[558]</a></p>
+
+<p><b>548. Ferments Employed.</b>—Both the pepsins of commerce and those
+prepared directly from the stomachs of pigs may be used. The commercial
+scale pepsin is found, as a rule, entirely satisfactory, and more
+uniform results are secured by its use than from pepsin solutions made
+from time to time from pig stomachs. In the preparation of the pepsin
+solution one gram of the best scale pepsin is dissolved in one liter
+of 0.33 per cent hydrochloric acid. Two grams of the sample of food
+products, in fine powder, are suspended in 100 cubic centimeters of the
+solution and kept, with frequent shaking, at a temperature of 40° for
+twelve hours. The contents of the flask are poured on a wet filter, the
+residue on the filter well washed with water not above 40°, the filter
+paper and its contents transferred to a kjeldahl flask and the residual
+nitrogen determined and multiplied by 6.25 to get the undigested
+proteid matter. A large number of digestions can be conducted at once
+in a bath shown in <a href="#FIG_117">Fig. 117</a>.<a id="FNanchor_559" href="#Footnote_559" class="fnanchor">[559]</a>
+The quantity of water in the bath should be as large as possible.</p>
+
+<p><b>549. Digestion in Pepsin and Pancreatin.</b>—The digestion of the
+proteids is not as a rule wholly accomplished by the stomach juices,
+and, therefore, in order to secure in artificial digestion results
+approximating those produced in the living organism, it is necessary
+to follow the treatment with pepsin by a similar one with the pancreas
+<span class="pagenum"><a id="Page_559"></a>[Pg 559]</span>
+juices. The method employed in this laboratory is essentially that of
+Stutzer modified by Wilson.<a id="FNanchor_560" href="#Footnote_560" class="fnanchor">[560]</a></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_117" src="images/fig117.jpg" alt="" width="600" height="273" >
+    <p class="center spb1">Fig. 117. Bath for Artificial Digestion.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_560"></a>[Pg 560]</span>
+The residue from the pepsin digestion, after washing, is treated for
+six hours at near 40° with 100 cubic centimeters of pancreas solution,
+prepared as follows:</p>
+
+<p>Free the pancreas of a healthy steer of fat, pass it through a sausage
+grinder, rub one kilogram in a mortar with fine sand and allow to stand
+for a day or longer. Add three liters of lime water, one of glycerol,
+of 1.23 specific gravity, and a little chloroform and set aside for
+six days. Separate the liquor by pressure in a bag and filter it
+through paper. Before using, mix a quarter of a liter of the filtrate
+with three-quarters of a liter of water and five grams of dry sodium
+carbonate, or its equivalent crystallized, heat from 38° to 40° for
+two hours and filter.<a id="FNanchor_561" href="#Footnote_561" class="fnanchor">[561]</a>
+In order to avoid the trouble of preparing the pancreas solution pure
+active pancreatin may be  used.<a id="FNanchor_562" href="#Footnote_562" class="fnanchor">[562]</a>
+One and a half grams of pure pancreatin and three grams of sodium
+carbonate are dissolved in one liter of water and 100 cubic centimeters
+of this solution are used for each two grams of the sample. In all
+cases where commercial pepsin and pancreatin are used, their activity
+should be tested with bodies such as boiled whites of eggs, whose
+coefficient of digestibility is well known and those samples be
+rejected which do not prove to have the required  activity.<a id="FNanchor_563" href="#Footnote_563" class="fnanchor">[563]</a></p>
+
+<p><b>550. Digestion in Pancreas Extract.</b>—In order to save the time
+required for successive digestions in pepsin and pancreatin Niebling
+has proposed to make the digestion in the pancreas extract alone.<a id="FNanchor_564" href="#Footnote_564" class="fnanchor">[564]</a>
+This process and also a slight modification of it have been used with
+success by Bigelow and McElroy.<a id="FNanchor_565" href="#Footnote_565" class="fnanchor">[565]</a>
+Two grams of the sample are washed with ether and placed in a digestion
+flask with 100 cubic centimeters of two-tenths per cent hydrochloric
+acid. The contents of the flask are boiled for fifteen minutes, cooled,
+and made slightly alkaline with sodium carbonate. One hundred cubic
+centimeters of the unfiltered pancreas solution, prepared as directed
+above, are added and the digestion continued at 40° for six hours. The
+residue is thrown on a filter, washed, and the nitrogen determined.
+The method is simplified by the substitution of active commercial
+pancreatin for pancreas extract. The solution of the ferment is made of
+the same strength as is specified above.
+<span class="pagenum"><a id="Page_561"></a>[Pg 561]</span></p>
+
+<p><b>551. Artificial Digestion of Cheese.</b>—The artificial digestion
+of cheese is conducted by Stutzer as follows:<a id="FNanchor_566" href="#Footnote_566" class="fnanchor">[566]</a></p>
+
+<p>The digestive liquor is prepared from the fresh stomachs of pigs by
+cutting them into fine pieces and mixing with five liters of water and
+100 cubic centimeters of hydrochloric acid for each stomach. To prevent
+decomposition, two and a half grams of thymol, previously dissolved in
+alcohol, are added to each 600 cubic centimeters of the mixture. The
+mixture is allowed to stand for a day with occasional shaking, poured
+into a flannel bag and the liquid portion allowed to drain without
+pressing. The liquor obtained in this way is filtered, first through
+coarse and then through fine paper, and when thus prepared will keep
+several months without change. It is advisable to determine the content
+of hydrochloric acid in the liquor by titration and this content should
+be two-tenths of a per cent. The cheese to be digested is mixed with
+sand as previously described, freed of fat by extraction with ether,
+and a quantity corresponding to five grams of cheese placed in a
+beaker, covered with half a liter of the digestive liquor and kept at
+a temperature of 40° for forty-eight hours. At intervals of two hours
+the flasks are well shaken and five cubic centimeters of a ten per
+cent solution of hydrochloric acid added and this treatment continued
+until the quantity of hydrochloric acid amounts to one per cent. After
+the digestion is finished, the contents of the beaker are thrown on a
+filter, washed with water and the nitrogen determined in the usual way
+in the residue. By allowing the pepsin solution to act for two days as
+described above, the subsequent digestion with pancreas solution is
+superfluous.</p>
+
+<p><b>552. Suggestions Regarding Manipulation.</b>—The filter papers
+should be as quick working as possible to secure the separation of
+all undissolved particles. They should be of sufficient size to hold
+the whole contents of the digestion flask at once, since if allowed
+to become empty and partially dry, filtration is greatly impeded. The
+residue should be dried at once if not submitted immediately to moist
+combustion. After drying, the determination of the nitrogen can be made
+at any convenient time. Beaker flasks, <i>i. e.</i>, lip erlenmeyers
+<span class="pagenum"><a id="Page_562"></a>[Pg 562]</span>
+with a wide mouth are most convenient for holding the materials during
+digestion. The flasks are most conveniently held by a crossed rubber
+band attached at either end to pins in the wooden slats extending
+across the digestive bath. The bath should be suspended by cords from
+supports on the ceiling and a gentle rotatory motion imparted to it
+resembling the peristaltic action attending natural digestion.</p>
+
+<p><b>553. Natural Digestion.</b>—The digestion of foods by natural
+processes is determined chiefly by the classes of ferments already
+noted. The principle underlying digestive experiments with the animal
+organism may be stated as follows: A given weight of food of known
+composition is fed to a healthy animal under the conditions of careful
+control and preparation already mentioned. The solid dejecta of the
+animal during a given period are collected and weighed daily, being
+received directly from the animal in an appropriate bag, safely
+secured, as is shown in the accompanying <a href="#FIG_118">figure</a>.
+The dejecta are weighed, dried, ground to a fine powder, mixed and
+a representative part analyzed. The difference between the solid
+bodies in the dejecta and those given in the food during the period
+of experiment represents those nutrients which have been digested and
+absorbed during the passage of the food through the alimentary canal.
+The urine, containing solid bodies representing the waste of the animal
+organism, does not require to be analyzed for the simple control of
+digestive activity outlined above. In a complete determination of this
+kind the exhalations from the surface of the body and from the lungs
+are also determined. In the latter case the human animal is selected
+for the experiment; in the former it is more convenient to employ the
+lower animals, such as the sheep and cow.</p>
+
+<p>The arrangement of the stalls and of the apparatus for collecting the
+excreta should be such as is both convenient and effective.<a id="FNanchor_567" href="#Footnote_567" class="fnanchor">[567]</a></p>
+
+<p>The method of constructing a bag for attachment to a sheep is shown in
+<a href="#FIG_118">Fig. 118</a>. It is made according to the directions given by
+Gay, of heavy cloth and in such a way as to fit closely the posterior parts of the
+animal.<a id="FNanchor_568" href="#Footnote_568" class="fnanchor">[568]</a>
+When attached, its appearance is shown in <a href="#FIG_119">Fig. 119</a>.
+<span class="pagenum"><a id="Page_563"></a>[Pg 563]</span></p>
+
+<div class="figcontainer smcap">
+  <div class="figsub">
+   <p class="spa3">&nbsp;</p>
+   <img id="FIG_118" src="images/fig118.jpg" alt="" width="300" height="129" >
+   <p class="center spa2">Fig. 118.—Bag for<br> Collecting Feces.</p>
+  </div>
+  <div id="FIG_119" class="figsub">
+   <img src="images/fig119.jpg" alt="" width="200" height="458" >
+   <p class="center">Fig. 119.—Fecal Bag Attachment.</p>
+   </div>
+</div>
+
+<p>Healthy animals in the prime of life are used, and the feeding
+experiments are conducted with as large a number of animals as
+possible, in order to eliminate the effects of idiosyncrasy. The food
+used is previously prepared in abundant quantity and its composition
+determined by the analysis of an average sample.</p>
+
+<p>The feeding period is divided into two parts. In the first part the
+animal is fed for a few days with the selected food until it is certain
+that all the excreta are derived from the nutrients used. In the second
+part the same food is continued and the excreta collected, weighed, the
+moisture determined, and the total weight of the water-free excreta
+ascertained. The first part should be of at least seven and the second
+of at least five days duration. The urine and dung are analyzed
+separately. Males are preferred for the digestion experiments because
+of the greater ease of collecting the urine and feces without mixing.
+For ordinary purposes the feces only are collected. The methods of
+analysis do not differ from those described for the determination of
+the usual ingredients of a food.</p>
+
+<p><i>Example.</i>—The following data taken from the results of digestive
+<span class="pagenum"><a id="Page_564"></a>[Pg 564]</span>
+experiments, obtained at the Maine Station, will illustrate the method
+of comparing the composition of the food with that of the feces and
+of determining the degree of digestion which the proteids and other
+constituents of the food have undergone.</p>
+
+<p class="f120"><b><span class="smcap">Composition of Maize Fodder and of Feces<br>
+Therefrom after Feeding to Sheep.</span></b></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc fs_110" colspan="7"><span class="smcap">Before Drying.</span></th>
+   </tr><tr>
+      <th class="tdc bb">Food</th>
+      <th class="tdc bb">Water,<br>&nbsp;per cent.&nbsp;</th>
+      <th class="tdc bb">Ash,<br>&nbsp;per cent.&nbsp;</th>
+      <th class="tdc bb">Proteid,<br>&nbsp;per cent.&nbsp;</th>
+      <th class="tdc bb">Fiber,<br>&nbsp;per cent.&nbsp;</th>
+      <th class="tdc bb">Fat,<br>&nbsp;per cent.&nbsp;</th>
+      <th class="tdc bb">Undetermined,<br>per cent.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Sweet maize</td>
+      <td class="tdc">83.85</td>
+      <td class="tdc">1.13</td>
+      <td class="tdc">2.18</td>
+      <td class="tdc">4.14</td>
+      <td class="tdc">0.62</td>
+      <td class="tdc">8.08</td>
+   </tr><tr>
+      <td class="tdl">Feces</td>
+      <td class="tdc">72.01</td>
+      <td class="tdc">...</td>
+      <td class="tdc">...</td>
+      <td class="tdc">...</td>
+      <td class="tdc">...</td>
+      <td class="tdc">...</td>
+   </tr><tr>
+      <td class="tdc fs_110" colspan="7">&nbsp;<br><b><span class="smcap">Dry.</span></b></td>
+   </tr><tr>
+      <td class="tdc bb"><b>Food</b></td>
+      <td class="tdc bb">&nbsp;</td>
+      <td class="tdc bb"><b>Ash,<br>&nbsp;per cent.&nbsp;</b></td>
+      <td class="tdc bb"><b>Proteid,<br>&nbsp;per cent.&nbsp;</b></td>
+      <td class="tdc bb"><b>Fiber,<br>&nbsp;per cent.&nbsp;</b></td>
+      <td class="tdc bb"><b>Fat,<br>&nbsp;per cent.&nbsp;</b></td>
+      <td class="tdc bb"><b>Undetermined,<br>per cent.</b></td>
+   </tr><tr>
+      <td class="tdl">Sweet maize</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&#8199;7.01</td>
+      <td class="tdc">13.52</td>
+      <td class="tdc">25.63</td>
+      <td class="tdc">3.86</td>
+      <td class="tdc">49.98</td>
+   </tr><tr>
+      <td class="tdl">Feces</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">14.42</td>
+      <td class="tdc">17.52</td>
+      <td class="tdc">19.34</td>
+      <td class="tdc">2.68</td>
+      <td class="tdc">46.04</td>
+   </tr><tr>
+      <td class="tdc fs_110" colspan="7">&nbsp;<br><b><span class="smcap">Daily Weights.</span></b></td>
+   </tr><tr>
+      <td class="tdc bb"><b>Food</b></td>
+      <td class="tdc bb">&nbsp;</td>
+      <td class="tdc bb">&nbsp;</td>
+      <td class="tdc bb">&nbsp;</td>
+      <td class="tdc bb">&nbsp;</td>
+      <td class="tdc bb"><b>&nbsp;Green,&nbsp;<br>grams.</b></td>
+      <td class="tdc bb"><b>Dry,<br>&nbsp;grams.&nbsp;</b></td>
+   </tr><tr>
+      <td class="tdl">Sweet maize</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">2521</td>
+      <td class="tdc">407</td>
+   </tr><tr>
+      <td class="tdl">Feces</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&#8199;445</td>
+      <td class="tdc">125</td>
+   </tr><tr>
+      <td class="tdc fs_110" colspan="7">&nbsp;<br><b><span class="smcap">Per Cent Digested.</span></b></td>
+   </tr><tr>
+      <td class="tdc bb"><b>Food</b></td>
+      <td class="tdc bb">&nbsp;</td>
+      <td class="tdc bb"><b>Ash,</b></td>
+      <td class="tdc bb"><b>Proteid,</b></td>
+      <td class="tdc bb"><b>Fiber,</b></td>
+      <td class="tdc bb"><b>Undetermined,</b></td>
+      <td class="tdc bb"><b>Fat,</b></td>
+   </tr><tr>
+      <td class="tdl">Sweet maize</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">37.0</td>
+      <td class="tdc">60.2</td>
+      <td class="tdc">76.9</td>
+      <td class="tdc">71.8</td>
+      <td class="tdc">78.3</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>In the above instance it is seen that the coefficient of digestibility
+extended from 37.0 per cent in the case of the mineral components
+of the food, to 78.3 per cent in the case of the fats. These data
+are taken only from the results obtained from a single sheep and one
+article of food. The mean data secured from two animals and three kinds
+of maize fodder show the following per cents of digestibility: Ash
+39.4, proteid 61.8, fiber 76.7, undetermined matters 72.1, fat 76.4.
+The undetermined matters are those usually known as nitrogen free
+extract and composed chiefly of pentosans and other carbohydrates.<a id="FNanchor_569" href="#Footnote_569" class="fnanchor">[569]</a></p>
+
+<p><b>554. Natural Digestibility of Pentosans.</b>—The digestibility
+of pentosan bodies in foods under the influence of natural ferments
+has been investigated by Lindsey and Holland.<a id="FNanchor_570" href="#Footnote_570" class="fnanchor">[570]</a>
+The feeding and
+collection of the feces is carried on as described above and the
+relative proportions of pentosan bodies in the foods and feces
+<span class="pagenum"><a id="Page_565"></a>[Pg 565]</span>
+determined by estimating the furfuraldehyd as prescribed in paragraph
+<b><a href="#P_150">150</a></b>.<a id="FNanchor_571" href="#Footnote_571" class="fnanchor">[571]</a></p>
+
+<h3>PRESERVED MEATS.</h3>
+
+<p><b>555. Methods of Examination.</b>—In general the methods of
+examination are the same as those applied in the study of fresh
+meats. The contents of water, salt and other preservatives, fat and
+nitrogenous matters are of most importance. When not already in a fine
+state, the preserved meats are run through meat cutters until reduced
+to a fine pulp. Most potted meats are already in a state of subdivision
+well suited to analytical work. The composition of preserved meats has
+been thoroughly studied in this laboratory by Davis.<a id="FNanchor_572" href="#Footnote_572" class="fnanchor">[572]</a></p>
+
+<p><b>556. Estimation Of Fat.</b>—Attention has already been called to
+the difficulty of extracting the fat from meats by ether or other
+solvents.<a id="FNanchor_573" href="#Footnote_573" class="fnanchor">[573]</a>
+In preserved meats, as well as in fresh, it is preferable to adopt some
+method which will permit of the decomposition of the other organic
+matters and the separation of the fat in a free state. The most
+promising methods are those employed in milk analyses for the solution
+of nitrogenous matters. Sulfuric or hydrochloric acid may be used for
+this purpose, preference being given to sulfuric. The separated fats
+may be taken up with ether or separated by centrifugal action. A method
+of this kind for preserved meats, suggested by Hefelmann, is described below.</p>
+
+<p>About six grams of the moist preserved meat are placed in a calibrated
+test tube and dissolved in twenty-five cubic centimeters of fuming
+hydrochloric acid. The tube is placed in a water bath, quickly heated
+to boiling and kept at that temperature for half an hour. About twenty
+cubic centimeters of cold water are added and the temperature lowered
+to 30°, then twenty cubic centimeters of ether and the tube gently
+shaken to promote the solution of the fat. When the ether layer has
+separated, its volume is read and an aliquot part removed by means of a
+pipette, dried and weighed. The separation of the ethereal solution is
+greatly promoted by whirling.</p>
+
+<p>The mean proportions of the ingredients of preserved meats are about
+as follows:
+<span class="pagenum"><a id="Page_566"></a>[Pg 566]</span></p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdr">Per cent.</td>
+   </tr><tr>
+      <td class="tdl_ws1">Water</td>
+      <td class="tdr_ws1">67.0</td>
+   </tr><tr>
+      <td class="tdl_ws1">Dry matter</td>
+      <td class="tdr_ws1">33.0</td>
+   </tr><tr>
+      <td class="tdl" colspan="2">&nbsp;</td>
+   </tr><tr class="fs_105">
+      <td class="tdl">Of which</td>
+      <td class="tdr_ws1">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl_ws1">Nitrogenous bodies</td>
+      <td class="tdr_ws1">19.0</td>
+   </tr><tr>
+      <td class="tdl_ws1">Fats</td>
+      <td class="tdr_ws1">10.5</td>
+   </tr><tr>
+      <td class="tdl_ws1">Ash and undetermined</td>
+      <td class="tdr_ws1">&#8199;3.5</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>557. Meat Preservatives.</b>—Various bodies are used to give taste
+and color to preserved meats and to preserve them from fermentation.
+The most important of these bodies are common salt, potassium and
+sodium nitrates, sulfurous, boric, benzoic and salicylic acids,
+formaldehyd, saccharin and hydronaphthol. A thorough study of the
+methods of detecting and isolating these bodies has been made in this
+laboratory by Davis and the results are yet to be published as a part
+of Bulletin 13.</p>
+
+<h3>DETERMINATION OF NUTRITIVE VALUES.</h3>
+
+<p><b>558. Nutritive Value of Foods.</b>—The value of a food as a
+nutrient depends on the amount of heat it gives on combustion in the
+tissues of the body, <i>i. e.</i> oxidation, and in its fitness to
+nourish the tissues of the body, to promote growth and repair waste.
+The foods which supply heat to the body are organic in their nature and
+are typically represented by fats and carbohydrates. The foods which
+promote growth and supply waste are not only those which preeminently
+supply heat, but also include the inorganic bodies and organic
+nitrogenous matters represented typically by the proteids. It is not
+proper to say that one class of food is definitely devoted to heat
+forming and another to tissue building, inasmuch as the same substance
+may play an important rôle in both directions. As heat formers,
+carbohydrates and proteids have an almost equal value, as measured by
+combustion in oxygen, while fat has a double value for this purpose.
+The assumption that combustion in oxygen forms a just criterion for
+determining the value of a food must not be taken too literally. There
+are only a few bodies of the vast number which burn in oxygen that are
+capable of assimilation and oxidation by the animal organism. Only
+those parts of the food that become soluble and assimilable under
+the action of the digestive ferments, take part in nutrition and the
+<span class="pagenum"><a id="Page_567"></a>[Pg 567]</span>
+percentage of food materials digested varies within wide limits but
+rarely approaches 100. It may be safely said that less than two-thirds
+of the total food materials ingested are dissolved, absorbed,
+decomposed and assimilated in the animal system. We have no means
+of knowing how far the decomposition (oxidation) extends before
+assimilation, and therefore no theoretical means of calculating the
+quantity of heat which is produced during the progress of digestion.
+The vital thermostat is far more delicate than any mechanical
+contrivance for regulating temperature and the quantity of food, in a
+state of health, converted into heat, is just sufficient to maintain
+the temperature of the body at a normal degree. Any excess of heat
+produced, as by violent muscular exertion, is dissipated through the
+lungs, the perspiration and other secretions of the body.</p>
+
+<p>Pure cellulose or undigestible fiber, when burned in oxygen, will
+give a thermal value approximating that of sugar, but no illustration
+is required to show that when taken into the system the bodily heat
+afforded by it is insignificant in quantity.</p>
+
+<p>Thermal values, therefore, have little comparative usefulness
+in determining nutritive worth, except when applied to foods of
+approximately the same digestive coefficient.</p>
+
+<p><b>559. Comparative Value of Food Constituents.</b>—It has already
+been noted that, judged by combustion in oxygen, carbohydrates
+and proteids have about half the thermal value possessed by fats.
+Commercially, the values of foods depend in a far greater degree on
+their flavor and cooking qualities than upon the amount of nutrition
+they contain. Butter fat, which is scarcely more nutritious than
+tallow, is worth twice as much in the market, while the prices paid for
+vegetables and fruits are not based to any great extent on their food
+properties.<a id="FNanchor_574" href="#Footnote_574" class="fnanchor">[574]</a>
+In cereals, especially in wheat, the quantity of fat is relatively
+small, and starch is the preponderating element. In meats,
+carbohydrates are practically eliminated and fats and proteids are the
+predominating constituents.</p>
+
+<p>In the markets, fats and proteids command far higher prices than sugars
+and starches. The relative commercial food value of a cereal may be
+roughly approximated by multiplying the percentages of fat and protein
+<span class="pagenum"><a id="Page_568"></a>[Pg 568]</span>
+by two and a half and adding the products to the percentage of
+carbohydrates less insoluble fiber. This method was adopted in valuing
+the cereals at the World’s Columbian Exposition.<a id="FNanchor_575" href="#Footnote_575" class="fnanchor">[575]</a></p>
+
+<p><b>560. Nutritive Ratio.</b>—In solid foods the nutritive ratio
+is that existing between the percentage of proteids and that of
+carbohydrates, increased by multiplying the fat by two and a half and
+adding the product. In a cereal containing twelve per cent of protein,
+seventy-two of carbohydrates, exclusive of fiber, and three of fat, the
+ratio is 12: 72 + 3 × 2.5 = 6.5. Instead of calculating the nutritive
+ratio directly from the data obtained by analysis, it may be reckoned
+from the per cents of the three substances in the sample multiplied by
+their digestive coefficient. Since the relative amounts of proteids,
+fats and carbohydrates digested do not greatly differ, the numerical
+expression of the nutritive ratio is nearly the same when obtained by
+each of these methods of calculation.</p>
+
+<p>Where the proportion of protein is relatively large the ratio is called
+narrow, 1: 4 ... 6. When the proportion of protein is relatively small
+the ratio is called broad 1: 8 ... 12. In feeding, the nutritive ratio
+is varied in harmony with the purpose in view, a narrow ratio favoring
+the development of muscular energy, and a wide one promoting the
+deposition of fat and the development of heat. These principles guide
+the scientific farmer in mixing rations for his stock, the work horses
+receiving a comparatively narrow and the beeves a relatively wide ratio
+in their food.</p>
+
+<p><b>561. Calorimetric Analyses of Foods.</b>—The general principles of
+calorimetry have been already noticed. The theoretical and chemical
+relations of calorimetry have been fully discussed by Berthelot,
+Thomsen, Ostwald and Muir.<a id="FNanchor_576" href="#Footnote_576" class="fnanchor">[576]</a>
+In the analyses of foods the values as determined by calculation or
+combustion are of importance in determining the nutritive relations.</p>
+
+<p>Atwater has presented a résumé of the history and importance of
+the calorimetric investigations of foods to which the analyst is
+referred.<a id="FNanchor_577" href="#Footnote_577" class="fnanchor">[577]</a></p>
+
+<p>In the computation of food values the percentages of proteids,
+carbohydrates and fats are determined and the required data obtained by
+<span class="pagenum"><a id="Page_569"></a>[Pg 569]</span>
+applying the factors 4100, 5500 and 9300 calories for one gram of
+carbohydrates, proteids and fats respectively.</p>
+
+<p>For most purposes the computed values are sufficient, but it is well to
+check them from time to time by actual combustions in a calorimeter.</p>
+
+<p><b>562. Combustion in Oxygen.</b>—The author made a series of
+combustions of carbonaceous materials in oxygen at the laboratory of
+Purdue University in 1877, the ignition being secured by a platinum
+wire rendered incandescent by the electric current. The data obtained
+were unsatisfactory on account of the crudeness of the apparatus. The
+discovery of the process of burning the samples in oxygen at a high
+pressure has made it possible to get expressions of thermal data which
+while not yet perfect, possess a working degree of accuracy. The best
+form of bomb calorimeter heretofore employed is that of Hempel, as
+modified by Atwater and Woods.<a id="FNanchor_578" href="#Footnote_578" class="fnanchor">[578]</a></p>
+
+<p>A section of this calorimeter, with all the parts in place, is shown in
+<a href="#FIG_120">Fig. 120</a>.</p>
+
+<p>In the figure the steel cylinder <i>A</i>, about 12.5 centimeters deep
+and 6.2 in diameter, represents the chamber in which the combustion
+takes place. Its walls are about half a centimeter thick and it weighs
+about three kilograms. It is closed, when all the parts are ready and
+the sample in place, by the collar <i>C</i>, which is secured gas tight
+by means of a powerful spanner. The cover is provided with a neck
+<i>D</i> carrying a screw <i>E</i> and a valve screw <i>F</i>. In the
+neck <i>D</i>, where the bottom of the cylinder screw <i>E</i> rests,
+is a shoulder fitted with a lead washer. Through <i>G</i> the oxygen
+used for combustion is introduced. The upper edge of the cylinder
+<i>A</i> is beveled and fits into a groove in the cover <i>B</i>,
+carrying a soft metal washer. To facilitate the screwing on of the
+cover, ball bearings <i>KK</i>, made of hard steel, are introduced
+between the collar and the cover. The platinum wires <i>H</i> and
+<i>I</i> support the platinum crucible holding the combustible bodies
+which are ignited by raising the spiral iron wire connecting them
+to the temperature of fusion by an electric current. The combustion
+apparatus when charged is immersed in a metal cylinder <i>M</i>,
+containing water and resting on small cylinders of cork. The water is
+<span class="pagenum"><a id="Page_570"></a>[Pg 570]</span>
+stirred by the apparatus <i>LL</i>. The cylinder <i>M</i> is contained
+in two large concentric cylinders, <i>N</i>, <i>O</i>, made of
+non-conducting materials and covered with disks of hard rubber. The
+space between <i>O</i> and <i>N</i> may be filled with water. The
+temperature is measured by the thermometer <i>P</i>, graduated to
+hundredths of a degree and the reading is best accomplished by means of
+a cathetometer.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_120" src="images/fig120.jpg" alt="" width="400" height="651" >
+    <p class="center spb1">Fig. 120. Hempel and Atwater’s<br> Calorimeter.</p>
+</div>
+
+<p><b>563. The Williams Calorimeter.</b>—The calorimeter bomb has been
+improved by Williams by making it of aluminum bronze of a spheroidal
+shape. The interior of the bomb is plated with gold. By an ingenious
+arrangement of contacts the firing is secured by means of a permanently
+insulated electrode fixed in the side of the bomb. The calorimetric
+water, as well as that in the insulating vessel, is stirred by means of
+an electrical screw so regulated as to produce no appreciable degree of
+heat mechanically. The combustion is started by fusing a fine platinum
+wire of definite length and thickness by means of an electric current.
+The heat value of this fusion is determined and the calories produced
+deducted from the total calories of the combustion. The valve admitting
+<span class="pagenum"><a id="Page_571"></a>[Pg 571]</span>
+the oxygen is sealed automatically on breaking connection with the
+oxygen cylinder. The effluent gases, at the end of the combustion, may
+be withdrawn through an alkaline solution and any nitric acid therein
+thus be fixed and determined.<a id="FNanchor_579" href="#Footnote_579" class="fnanchor">[579]</a></p>
+
+<p><b>564. Manipulation and Calculation.</b>—The material to be burned
+is conveniently prepared by pressing it into tablets. The oxygen is
+supplied from cylinders, of which two should be used, one at a pressure
+of more than twenty atmospheres. By this arrangement a pump is not
+required.</p>
+
+<p>In practical use, a known weight of the substance to be burned is
+placed in the platinum capsule, the cover of the bomb screwed on,
+after all adjustments have been made, and the apparatus immersed in
+the water contained in <i>M</i>, which should be about 2° below room
+temperature. All the covers are placed in position and the temperature,
+of the water in <i>M</i> begins to rise. Readings of the thermometer
+are taken at intervals of about one minute for six minutes, at which
+time the temperature of the bomb and calorimetric water may be regarded
+as sensibly the same. The electric current is turned on, the iron wire
+at once melts, ignites the substance and the combustion rapidly takes
+place. In the case of bodies which do not burn readily Atwater adds
+to them some naphthalene, the thermal value of which is previously
+determined. The calories due to the combustion of the added naphthalene
+are deducted from the total calories obtained.</p>
+
+<p>The temperature of the water in <i>M</i> rises rapidly at first, and
+readings are made at intervals of one minute for five minutes, and then
+again after ten minutes. The first of the initial readings, the one at
+the moment of turning on the current, and the last one mentioned above
+are the data from which the correction, made necessary by the influence
+of the temperature of the room, is calculated by the following
+formulas.<a id="FNanchor_580" href="#Footnote_580" class="fnanchor">[580]</a></p>
+
+<p>The preliminary readings of the thermometer at one minute intervals are
+represented by <i>t</i>₁, <i>t</i>₂, <i>t</i>₃ ... <i>t</i>ₙ₁. The last
+observation tₙ₁ is taken as the beginning temperature of the combustion
+and is represented in the formulas for calculations by Θ₁. The readings
+after combustion are also made at intervals of one minute, and are
+designated by Θ₂, Θ₃ ... Θₙ. The readings are continued until there is
+no observed change between the last two. Generally this is secured by
+five or six readings.
+<span class="pagenum"><a id="Page_572"></a>[Pg 572]</span></p>
+
+<p>The third period of observations begins with the last reading Θₙ,
+which in the next series is represented by <i>tʹ</i>₁, <i>tʹ</i>₂ ...
+<i>tʹ</i>ₙ₂.</p>
+
+<p>In order to make the formulas less cumbersome let</p>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdc bb"><i>t</i>ₙ₁ - <i>t</i>₁</td>
+      <td class="tdl" rowspan="2">&nbsp;= <i>v</i>,</td>
+   </tr><tr>
+      <td class="tdc"><i>n</i>₁ - 1</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdc bb"><i>tʹ</i>ₙ₁ - <i>tʹ</i>₁</td>
+      <td class="tdl" rowspan="2">&nbsp;= <i>vʹ</i>,</td>
+   </tr><tr>
+      <td class="tdc"><i>n</i>₂ - 1</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdc bb"><i>t</i>₁ + <i>t</i>₂ + <i>t</i>₃ ... <i>t</i>ₙ₁</td>
+      <td class="tdl" rowspan="2">&nbsp;= <i>t</i>,</td>
+   </tr><tr>
+      <td class="tdc"><i>n</i>₁</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1 fs_110">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">and&emsp;&nbsp;</td>
+      <td class="tdc bb"><i>tʹ</i>₁ + <i>tʹ</i>₂ + <i>tʹ</i>₃ ... <i>tʹ</i>ₙ₂</td>
+      <td class="tdl" rowspan="2">&nbsp;= <i>tʹ</i>.</td>
+   </tr><tr>
+      <td class="tdc"><i>n</i>₂</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The correction to be made to the difference between Θₙ - Θ₁ for the
+influence of the outside temperature is determined by the formula of
+Regnault-Pfaundler, which is as follows:</p>
+
+<table class="spb1 fs_120">
+   <tbody><tr>
+      <td class="tdl" rowspan="2">∑ Δ<i>t</i> = &nbsp;</td>
+      <td class="tdc bb"><i>v</i> - <i>vʹ</i></td>
+      <td class="tdc" rowspan="2"><span class="fs_200">&nbsp;(</span> &nbsp;</td>
+      <td class="tdr"><sup>ⁿ⁻¹</sup></td>
+      <td class="tdl fs_150" rowspan="2">∑</td>
+      <td class="tdl" rowspan="2">&nbsp; Θ<i>r</i> + &nbsp;</td>
+      <td class="tdr bb">Θₙ + Θ₁</td>
+      <td class="tdl" rowspan="2">&nbsp; - <i>nt</i> <span class="fs_200">)</span> - (<i>n</i> - 1)<i>v</i>,</td>
+   </tr><tr>
+      <td class="tdc"><i>tʹ</i> - <i>t</i></td>
+      <td class="tdr">&nbsp;<sup>₁</sup>&nbsp;</td>
+      <td class="tdc">2</td>
+
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdr"><sub>n-1</sub></td>
+      <td class="tdc">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">in which &nbsp; <span class="fs_120">∑</span></td>
+      <td class="tdl">&nbsp; Θ<i>r</i></td>
+   </tr><tr>
+      <td class="tdr"><sup>1</sup>&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="no-indent">is calculated from the observation of the
+thermometer Θ₁, Θ₂ etc., made immediately after the combustion. It is
+equal to the sum of observations Θ₁, Θ₂ etc., increased by an arbitrary
+factor equivalent to (Θ₂ - Θ₁)/9, which is made necessary by reason
+of the irregularity of the temperature increase during the first
+minute after combustion, the mean temperature during that minute being
+somewhat higher than the mean of the temperatures at the commencement
+and end of that time.</p>
+
+<p>The quantity of heat formed by the combustion of the iron wire used for
+igniting the sample is to be deducted from the total heat produced.
+This correction may be determined once for all, the weight of the
+iron wire used being noted and that of any unburned portion being
+ascertained after the combustion.</p>
+
+<p>Ten milligrams of iron, on complete combustion, will give sixteen calories.</p>
+
+<p>In the combustion of substances containing nitrogen, or in case the
+free nitrogen of the air be not wholly expelled from the apparatus
+before the burning, nitric acid is formed which is dissolved by the
+water produced.
+<span class="pagenum"><a id="Page_573"></a>[Pg 573]</span></p>
+
+<p>The heat produced by the solution of nitric acid in water is 14.3
+calories per gram molecule. The quantity of nitric acid formed is
+determined by titration and a corresponding reduction made in the total
+calculated calories.</p>
+
+<p>In the titration of nitric acid it is advisable to make use of an
+alkaline solution, of which one liter is equivalent to 4.406 grams of
+nitric acid. One cubic centimeter of the reagent is equivalent to a
+quantity of nitric acid represented by one calorie.</p>
+
+<p>Since the materials of which the bomb is composed have a specific heat
+different from that of water, it is necessary to compute the water
+thermal value of each apparatus.</p>
+
+<p>The hydrothermal equivalent of the whole apparatus is most simply
+determined by immersing it at a given temperature in water of a
+different temperature.<a id="FNanchor_581" href="#Footnote_581" class="fnanchor">[581]</a>
+With small apparatus this method is quite sufficient, but there are
+many difficulties attending its application to large systems weighing
+several kilograms. In these cases the hydrothermal equivalent may be
+calculated from the specific heats of the various components of the apparatus.</p>
+
+<p>In calculating these values the specific heats of the various
+components of the apparatus are as follows:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Brass</td>
+      <td class="tdl_ws1">0.093</td>
+   </tr><tr>
+      <td class="tdl">Steel</td>
+      <td class="tdl_ws1">0.1097</td>
+   </tr><tr>
+      <td class="tdl">Platinum</td>
+      <td class="tdl_ws1">0.0324</td>
+   </tr><tr>
+      <td class="tdl">Copper</td>
+      <td class="tdl_ws1">0.09245</td>
+   </tr><tr>
+      <td class="tdl">Lead</td>
+      <td class="tdl_ws1">0.0315</td>
+   </tr><tr>
+      <td class="tdl">Oxygen</td>
+      <td class="tdl_ws1">0.2389</td>
+   </tr><tr>
+      <td class="tdl">Glass</td>
+      <td class="tdl_ws1">0.190</td>
+   </tr><tr>
+      <td class="tdl">Mercury</td>
+      <td class="tdl_ws1">0.0332</td>
+   </tr><tr>
+      <td class="tdl">Hard rubber<span class="ws2">&nbsp;</span></td>
+      <td class="tdl_ws1">0.33125</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><i>Example.</i>—It is required to calculate the hydrothermal value of
+a calorimeter composed of the following substances:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdc bb" colspan="2"><b>Hydrothermal<br>value.</b></td>
+   </tr><tr>
+      <td class="tdl">Steel bomb and cover, 2850 grams × 0.1097</td>
+      <td class="tdr">312.65</td>
+      <td class="tdl_wsp">grams.</td>
+   </tr><tr>
+      <td class="tdl">Platinum lining, capsule and wires, 120 grams × 0.0324</td>
+      <td class="tdr">3.89</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl">Lead washer, 100 grams × 0.0315</td>
+      <td class="tdr">3.15</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl">Brass outer cylinder, 500 grams × 0.093</td>
+      <td class="tdr">46.50</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl">Mercury in thermometer, 10 grams × 0.0332</td>
+      <td class="tdr">0.33</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl">Glass (part of thermometer in water), 10 grams × 0.19</td>
+      <td class="tdr">1.90</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl">Brass stirring apparatus (part in water), 100 grams × 0.093</td>
+      <td class="tdr bb">9.30</td>
+      <td class="tdc">”</td>
+   </tr><tr>
+      <td class="tdl_ws2">Total water value of system</td>
+      <td class="tdr">&nbsp; 377.72</td>
+      <td class="tdc">”</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_574"></a>[Pg 574]</span>
+When a bomb of 300 cubic centimeters capacity is filled with oxygen at
+a pressure of twenty-four atmospheres it will hold about ten grams of
+the gas, equivalent to a water value of 2.40 grams. Hence the water
+value of the above system when charged, assuming the bomb to be of the
+capacity mentioned, is 380.12 grams.</p>
+
+<p>If the cylinder holding the water be made of fiber or other
+non-conducting substance, its specific heat is best determined by
+filling it in a known temperature with water at a definite different
+temperature.</p>
+
+<p>It is advisable to have the water cylinder of such a size as to permit
+the use of a quantity of water for the total immersion of the bomb
+which will weigh, with the water value of the apparatus, an even number
+of grams. In the case above, 2622.28 grams of water placed in the
+cylinder will make a water value of 3,000 grams, which is one quite
+convenient for calculation.</p>
+
+<p><b>565. Computing the Calories of Combustion.</b>—In the preceding
+paragraph has been given a brief account of the construction of the
+calorimeter and of the methods of standardizing it and securing the
+necessary corrections in the data directly obtained in its use. An
+illustration of the details of computing the calories of combustion
+taken from the paper of Stohmann, Kleber and Langbein, will be a
+sufficient guide for the analyst in conducting the combustion and in
+the use of the data obtained.<a id="FNanchor_582" href="#Footnote_582" class="fnanchor">[582]</a></p>
+
+<div class="blockquot">
+<p>Weight of substance burned, 1.07 grams.</p>
+
+<p>Water value of system (water + apparatus), 2,500 grams.</p>
+
+<p>Preliminary thermometric readings, <i>t</i>₁ = 26.8; <i>t</i>₂ = 27.2;
+<i>t</i>₃ = 27.7; <i>t</i>₄ = 28.1; <i>t</i>₅ = 28.5; <i>t</i>ₙ₁ = 28.9.</p>
+
+<p>Thermometric reading after combustion, Θ₁ = 28.9; Θ₂ = 202; Θ₃ = 213;
+Θ₄ = 214.2; Θₙ = 214.0.</p>
+
+<p>Final thermometric readings, <i>tʹ</i>₁ = 214.0; <i>tʹ</i>₂ = 213.8;
+<i>tʹ</i>₃ = 213.6; <i>tʹ</i>₄ = 213.5; <i>tʹ</i>₅ = 213.3; <i>tʹ</i>₆
+= 213.1; <i>tʹ</i>₇ = 212.9; <i>tʹ</i>₈ = 212.7; <i>tʹ</i>₉ = 212.6;
+<i>tʹ</i>₁₀ = 212.4; <i>tʹ</i>ₙ₂ = 212.2.</p>
+
+<p>From the formulas given above the following numerical values are
+computed:</p>
+
+<p><span class="pagenum"><a id="Page_575"></a>[Pg 575]</span></p>
+
+<ul class="index">
+<li class="isub3"><i>v</i> = 0.42.</li>
+<li class="isub3"><i>vʹ</i> = -0.18.</li>
+<li class="isub3"><i>t</i> = 27.9.</li>
+<li class="isub3"><i>tʹ</i> = 213.1.</li>
+<li class="isub3"><i>n</i> = 5.</li>
+</ul>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdr"><sub>n-1</sub></td>
+      <td class="tdc" colspan="3">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl"><span class="fs_150">∑</span></td>
+      <td class="tdl">&nbsp;Θ<i>r</i> = Θ₁ + Θ₂ + Θ₃ + Θ₄ + &nbsp;</td>
+      <td class="tdc bb">Θ₂ - Θ₁</td>
+      <td class="tdl">&nbsp; = &nbsp;667.</td>
+   </tr><tr>
+      <td class="tdr"><sup>1</sup>&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">9</td>
+      <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>Substituting these values in the formula of Regnault-Pfaundler, the
+value of the correction for the influence of the external air is</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl fs_120" rowspan="2">∑ Δ<i>t</i> = &nbsp;</td>
+      <td class="tdc fs_300" rowspan="2">[&nbsp;</td>
+      <td class="tdc bb">0.42 - (-0.18)</td>
+      <td class="tdl fs_200" rowspan="2">&nbsp;(</td>
+      <td class="tdl" rowspan="2">&nbsp;677 + &nbsp;</td>
+      <td class="tdr bb">214 + 29</td>
+      <td class="tdl" rowspan="2">&nbsp; - (5 × 27.9)</td>
+      <td class="tdl fs_200" rowspan="2">)</td>
+      <td class="tdl" rowspan="2">&nbsp; - (4 × 0.42)</td>
+      <td class="tdc fs_300" rowspan="2">]</td>
+      <td class="tdl" rowspan="2">&nbsp; = 0.45,</td>
+   </tr><tr>
+      <td class="tdc">213.1 - 27.9</td>
+      <td class="tdc">2</td>
+   </tr>
+ </tbody>
+</table>
+
+<p class="no-indent">which is to be added to the end temperature (Θₙ = 214.0).</p>
+
+<p>The computation is then made from the following data:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Corrected end temperature (Θₙ + 0.45)</td>
+      <td class="tdr">&nbsp;&emsp;214.45</td>
+      <td class="tdc">&nbsp; = &nbsp;</td>
+      <td class="tdr">15°.3699</td>
+   </tr><tr>
+      <td class="tdl">Beginning temperature (Θ₁)</td>
+      <td class="tdr">28.90</td>
+      <td class="tdc">=</td>
+      <td class="tdr">12°.8406</td>
+   </tr><tr>
+      <td class="tdl">Increase in temperature</td>
+      <td class="tdr">185.55</td>
+      <td class="tdc">=</td>
+      <td class="tdr">2°.5293</td>
+   </tr><tr>
+      <td class="tdl">Total calories 2.5293 × 25000</td>
+      <td class="tdr">&nbsp;</td>
+      <td class="tdc">=</td>
+      <td class="tdr">6323.3</td>
+   </tr><tr>
+      <td class="tdl" colspan="3">Of which there were due to iron burned</td>
+      <td class="tdr">9.1</td>
+   </tr><tr>
+      <td class="tdl" colspan="3">&nbsp;”&emsp; &nbsp;”&emsp;&nbsp;&emsp;”&emsp; &nbsp;”&emsp;nitric acid dissolved</td>
+      <td class="tdr">8.2</td>
+   </tr><tr>
+      <td class="tdl" colspan="3">Total calories due to one gram of substance</td>
+      <td class="tdr">5893.5</td>
+   </tr>
+ </tbody>
+</table>
+</div>
+
+<p>The thermometric readings are given in the divisions of the thermometer
+which in this case are so adjusted as to have the number 28.90
+correspond to 12°.8406, and each division is nearly equivalent to
+0°.014 thermometric degree.</p>
+
+<p>The number of calories above given is the proper one when the
+computation is made to refer to constant volume. By reason of the
+consumption of oxygen and the change of temperature, although mutually
+compensatory, the pressure may be changed at the end of the operation.
+The conversion of the data obtained at constant volume referred to
+constant pressure may be made by the following formula, in which
+[<i>Q</i>] represents the calories from constant volume and <i>Q</i>
+the desired data for constant pressure, <i>O</i> the number of oxygen
+atoms, <i>H</i> the number of hydrogen atoms in a molecule of the
+substance, and 0.291 a constant for a temperature of about 18°, at
+which the observations should be made.
+<span class="pagenum"><a id="Page_576"></a>[Pg 576]</span></p>
+
+<table class="spb1 fs_105">
+   <tbody><tr>
+      <td class="tdl" rowspan="2"><i>Q</i> = [<i>Q</i>] +</td>
+      <td class="tdc fs_200" rowspan="2">&nbsp;(&nbsp;</td>
+      <td class="tdc bb"><i>H</i></td>
+      <td class="tdc" rowspan="2">&nbsp; -  <i>O</i></td>
+      <td class="tdc fs_200" rowspan="2">)</td>
+      <td class="tdc" rowspan="2">&nbsp; 0.291.</td>
+   </tr><tr>
+      <td class="tdc">2</td>
+   </tr>
+ </tbody>
+</table>
+
+<p id="P_566"><b>566. Calorimetric Equivalents.</b>—By the term calorie is
+understood the quantity of heat required to raise one gram of water,
+at an initial temperature of about 18°, one degree. The term ‘Calorie’
+denotes the quantity of heat, in like conditions, required to raise one
+kilogram of water one degree.</p>
+
+<p>For purposes of comparison and for assisting the analyst in adjusting
+his apparatus so as to give reliable results, the following data,
+giving the calories of some common food materials, are given:</p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bl bb bt" rowspan="2">Substance.<br>Proteids.</th>
+      <th class="tdc bl bb bt" rowspan="2">&nbsp;Calories.&nbsp;</th>
+      <th class="tdc bl br bb bt fs_110" colspan="5">Chemical composition.</th>
+   </tr><tr class="fs_110">
+      <th class="tdc bl bb">C.</th>
+      <th class="tdc bb">H.</th>
+      <th class="tdc bb">N.</th>
+      <th class="tdc bb">S.</th>
+      <th class="tdc bb br">O.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;Per cent.&nbsp;</td>
+      <td class="tdc">&nbsp;Per cent.&nbsp;</td>
+      <td class="tdc">&nbsp;Per cent.&nbsp;</td>
+      <td class="tdc">&nbsp;Per cent.&nbsp;</td>
+      <td class="tdc">&nbsp;Per cent.&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Serum albumin</td>
+      <td class="tdc">5917.8</td>
+      <td class="tdc">53.93</td>
+      <td class="tdc">7.65</td>
+      <td class="tdc">15.15</td>
+      <td class="tdc">1.18</td>
+      <td class="tdc">22.09</td>
+   </tr><tr>
+      <td class="tdl">Casein</td>
+      <td class="tdc">5867.0</td>
+      <td class="tdc">54.02</td>
+      <td class="tdc">7.33</td>
+      <td class="tdc">15.52</td>
+      <td class="tdc">0.75</td>
+      <td class="tdc">22.38</td>
+   </tr><tr>
+      <td class="tdl bb">Egg albumin</td>
+      <td class="tdc bb">5735.0</td>
+      <td class="tdc bb">52.95</td>
+      <td class="tdc bb">7.50</td>
+      <td class="tdc bb">15.19</td>
+      <td class="tdc bb">1.51</td>
+      <td class="tdc bb">22.85</td>
+   </tr><tr>
+      <td class="tdl">Meat free of fat and</td>
+      <td class="tdc bb" rowspan="2">5720.0</td>
+      <td class="tdc bb" rowspan="2">52.11</td>
+      <td class="tdc bb" rowspan="2">6.76</td>
+      <td class="tdc bb" rowspan="2">18.14</td>
+      <td class="tdc bb" rowspan="2">0.96</td>
+      <td class="tdc bb" rowspan="2">22.66</td>
+   </tr><tr>
+      <td class="tdl_wsp bb">extracted with water</td>
+   </tr><tr>
+      <td class="tdl">Peptone</td>
+      <td class="tdc">5298.8</td>
+      <td class="tdc">50.10</td>
+      <td class="tdc">6.45</td>
+      <td class="tdc">16.42</td>
+      <td class="tdc">1.24</td>
+      <td class="tdc">25.79</td>
+   </tr><tr>
+      <td class="tdl">Proteids (mean) Glycerids.</td>
+      <td class="tdc">5730.8</td>
+      <td class="tdc">52.71</td>
+      <td class="tdc">7.09</td>
+      <td class="tdc">16.02</td>
+      <td class="tdc">1.03</td>
+      <td class="tdc">23.15</td>
+   </tr><tr>
+      <td class="tdl">Butterfat</td>
+      <td class="tdc">9231.3</td>
+      <td class="tdc" colspan="5">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Linseed oil</td>
+      <td class="tdc">9488.0</td>
+      <td class="tdc" colspan="5">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Olive oil</td>
+      <td class="tdc">9467.0</td>
+      <td class="tdc" colspan="5">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl" colspan="7">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl" colspan="2">Carbohydrates.</td>
+      <td class="tdc" colspan="2">&nbsp;</td>
+      <td class="tdl_ws1" colspan="3"><b>Formula.</b></td>
+   </tr><tr>
+      <td class="tdl_ws1">Arabinose</td>
+      <td class="tdc">3722.0</td>
+      <td class="tdc" colspan="2">&nbsp;</td>
+      <td class="tdl" colspan="3">C₅H₁₀O₅</td>
+   </tr><tr>
+      <td class="tdl_ws1">Xylose</td>
+      <td class="tdc">3746.0</td>
+      <td class="tdc" colspan="2">&nbsp;</td>
+      <td class="tdl" colspan="3">C₅H₁₀O₅</td>
+   </tr><tr>
+      <td class="tdl_ws1">Dextrose</td>
+      <td class="tdc">3742.6</td>
+      <td class="tdc" colspan="2">&nbsp;</td>
+      <td class="tdl" colspan="3">C₆H₁₂O₆</td>
+   </tr><tr>
+      <td class="tdl_ws1">Levulose</td>
+      <td class="tdc">3755.0</td>
+      <td class="tdc" colspan="2">&nbsp;</td>
+      <td class="tdl" colspan="3">C₆H₁₂O₆</td>
+   </tr><tr>
+      <td class="tdl_ws1">Sucrose</td>
+      <td class="tdc">3955.2</td>
+      <td class="tdc" colspan="2">&nbsp;</td>
+      <td class="tdl" colspan="3">C₁₂H₂₂O₁₁</td>
+   </tr><tr>
+      <td class="tdl_ws1">Lactose</td>
+      <td class="tdc">3736.8</td>
+      <td class="tdc" colspan="2">&nbsp;</td>
+      <td class="tdl" colspan="3">C₁₂H₂₂O₁₁ + H₂O</td>
+   </tr><tr>
+      <td class="tdl_ws1">Maltose</td>
+      <td class="tdc">3949.3</td>
+      <td class="tdc" colspan="2">&nbsp;</td>
+      <td class="tdl" colspan="3">C₁₂H₂₂O₁₁</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>567. Distinction between Butter and Oleomargarin.</b>—Theoretically
+the heats of combustion of butter fat and oleomargarin are different
+and de Schweinitz and Emery propose to utilize this difference for
+analytical purposes.<a id="FNanchor_583" href="#Footnote_583" class="fnanchor">[583]</a>
+The samples of pure butter fat examined by them afforded 9320, 9327 and
+9362 calories, respectively. The calories obtained for various samples
+<span class="pagenum"><a id="Page_577"></a>[Pg 577]</span>
+of oleomargarin varied from 9574 to 9795. On mixing butter fat and
+oleomargarin, a progressive increase in calorimetric power is found,
+corresponding to the percentage of the latter constituent. Lards
+examined at the same time gave from 9503 to 9654 calories.</p>
+
+<h3>FRUITS, MELONS AND VEGETABLES.</h3>
+
+<p><b>568. Preparation of Sample.</b>—Fresh fruits and vegetables are
+most easily prepared for analysis by passing them through the pulping
+machine described on <a href="#Page_9">page 9</a>. Preliminary to the pulping
+they should be separated into skins, cores, seeds and edible portions, and the
+respective weights of these bodies noted. Each part is separately
+reduced to a pulp and, at once, a small quantity of the well mixed
+substance placed in a flat bottom dish and dried, first at a low
+temperature, and finally at 100°, or somewhat higher, and the
+percentage of water contained in the sample determined. The bulk of
+the sample, three or four kilograms, is dried on a tray of tinned or
+aluminum wire, first at a low and then at a high temperature, until
+all or nearly all the moisture is driven off. The dried pulp is then
+ground to as fine a powder as possible and subjected to the ordinary
+processes of analysis; <i>viz.</i>, the determination of the moisture,
+ash, nitrogen, fiber, fat and carbohydrates.</p>
+
+<p>In this method of analysis it is customary to determine the
+carbohydrates, exclusive of fiber, by subtracting the sum of the per
+cents of the other constituents and the nitrogen multiplied by 6.25
+from 100.</p>
+
+<p><b>569. Separation of the Carbohydrates.</b>—It is often desirable to
+determine the relative proportions of the more important carbohydrates
+which are found in fruits and vegetables. The pentoses and pentosans
+are estimated by the method described in paragraph <b><a href="#P_150">150</a></b>.
+The cane sugar, dextrose and levulose are determined by extracting a portion of
+the substance with eighty per cent alcohol and estimating the reducing
+sugars in the extract before and after inversion by the processes
+described in paragraphs <b><a href="#P_238">238-251</a></b>. The percentages of
+sugars deducted from the percentage of carbohydrates, exclusive of fiber, give
+the quantity of gums, pentosans, cellulose and pectose bodies present.</p>
+
+<p>Pectose exists chiefly in unripe fruits. By the action of the fruit
+<span class="pagenum"><a id="Page_578"></a>[Pg 578]</span>
+acids and of a ferment, pectose, in the process of ripening, is
+changed into pectin and similar hydrolyzed bodies soluble in water.
+The gelatinous properties of boiled fruits and fruit juices are due to
+these bodies, boiling accelerating their formation. In very ripe fruits
+the pectin is completely transformed into pectic acids. The galactan is
+estimated as described in <b><a href="#P_585">585</a></b>.</p>
+
+<p><b>570. Examination of the Fresh Matter.</b>—To avoid the changes
+which take place in drying fruits and vegetables, it is necessary to
+examine them in the fresh state. The samples may be first separated
+into meat and waste, as suggested above, or shredded as a whole.
+The moisture in the pulp is determined as indicated above, and in
+a separate portion the soluble matters are extracted by repeated
+treatment with cold water. The seeds, skins, cellulose, pectose and
+other insoluble bodies are thus separated from the sugars, pectins,
+pectic and other acids, and other soluble matters. The insoluble
+residue is rapidly dried and the relative proportions of soluble
+and insoluble matters determined. The estimation of these bodies is
+accomplished in the usual way.</p>
+
+<p><b>571. Examination of Fruit and Vegetable Juices.</b>—The fruits and
+vegetables are pulped, placed in a press and the juices extracted.
+The pressure should be as strong as possible and the press described
+in paragraph <b><a href="#P_280">280</a></b> is well suited to this purpose.
+The specific gravity of the expressed juice is obtained and the sucrose therein
+determined by polarization before and after inversion. The reducing
+sugars and the relative proportions of dextrose and levulose are
+determined in the usual manner. In grape juice dextrose is the
+predominant sugar while in many other fruits left hand or optically
+inactive sugars predominate. Soluble gums, dextrin, pectin etc., may be
+separated from the sugars by careful precipitation with alcohol, or the
+total solids, ash, nitrogen, ether extract and acids be determined and
+the carbohydrates estimated by difference. From the carbohydrates the
+total percentage of sugars is deducted and the remainder represents the
+quantity of pectin, gum and other carbohydrates present.</p>
+
+<p><b>572. Separation of Pectin.</b>—Pectin exists in considerable
+<span class="pagenum"><a id="Page_579"></a>[Pg 579]</span>
+quantities in the juice of ripe fruits (pears) and may be obtained in
+an approximately pure state from the juices by first removing proteids
+by the careful addition of tannin, throwing out the soluble lime
+salts with oxalic acid and precipitating the pectin with alcohol. On
+boiling with water, pectin is converted into parapectin, which gives
+a precipitate with lead acetate. Boiling with dilute acids converts
+pectin into metapectin, which is precipitated by a barium salt.</p>
+
+<p>Pectic acid may be obtained by boiling an aqueous extract (carrots)
+with sodium carbonate and precipitating the pectic with hydrochloric
+acid. It is a jelly-like body and dries to a horny mass.</p>
+
+<p><b>573. Determination of Free Acid.</b>—The free acid, or rather total
+acidity of fruits, is determined by the titration of their aqueous
+extracts or expressed juices with a set alkali. In common fruits and
+vegetables the acidity is calculated to malic <b>C₄H₆O₅</b>, in grapes to
+tartaric <b>C₄H₆O₆</b>, and in citrous fruits to citric acid <b>C₆H₈O₇</b>. Many
+other acids are found in fruits and vegetables, but those mentioned are
+predominant in the classes given.</p>
+
+<p><b>574. Composition of Common Fruits.</b>—The composition of common
+fruits in this country has been extensively investigated at the
+California Station and the following data are derived chiefly from its
+bulletins.<a id="FNanchor_584" href="#Footnote_584" class="fnanchor">[584]</a></p>
+
+<ul class="index">
+<li class="isub3"><b>(A)</b> = Total sugars in juice.</li>
+<li class="isub3"><b>(B)</b> = Sucrose in juice.</li>
+<li class="isub3"><b>(C)</b> = Dry organic matter.</li>
+</ul>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc_bott">Name.</th>
+      <th class="tdc">Total<br>weight.</th>
+      <th class="tdc">Rind<br>skin.</th>
+      <th class="tdc_bott">Seed.</th>
+      <th class="tdc_bott">Pulp.</th>
+      <th class="tdc_bott">Juice.</th>
+      <th class="tdc_bott fs_110">(A)</th>
+      <th class="tdc_bott fs_110">(B)</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdc">grams.</td>
+      <td class="tdc">&nbsp;per cent.&nbsp;</td>
+      <td class="tdc">&nbsp;per cent.&nbsp;</td>
+      <td class="tdc">&nbsp;per cent.&nbsp;</td>
+      <td class="tdc">cubic<br>centimeters.</td>
+      <td class="tdc">&nbsp;Per cent.&nbsp;</td>
+      <td class="tdc">&nbsp;Per cent.&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Naval orange</td>
+      <td class="tdc">300</td>
+      <td class="tdc">28.4</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">27.7</td>
+      <td class="tdc">107</td>
+      <td class="tdc">9.92</td>
+      <td class="tdc">4.80</td>
+   </tr><tr>
+      <td class="tdl">Mediterranean sweet orange</td>
+      <td class="tdc">202</td>
+      <td class="tdc">27.0</td>
+      <td class="tdc">0.8&#8199;</td>
+      <td class="tdc">24.0</td>
+      <td class="tdc">&#8199;86</td>
+      <td class="tdc">9.70</td>
+      <td class="tdc">4.35</td>
+   </tr><tr>
+      <td class="tdl">St. Michael’s orange</td>
+      <td class="tdc">138</td>
+      <td class="tdc">19.2</td>
+      <td class="tdc">1.6&#8199;</td>
+      <td class="tdc">25.9</td>
+      <td class="tdc">65.4</td>
+      <td class="tdc">8.71</td>
+      <td class="tdc">3.48</td>
+   </tr><tr>
+      <td class="tdl">Malta Blood orange</td>
+      <td class="tdc">177</td>
+      <td class="tdc">31.0</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">24.0</td>
+      <td class="tdc">71.0</td>
+      <td class="tdc">10.30&#8199;</td>
+      <td class="tdc">5.85</td>
+   </tr><tr>
+      <td class="tdl">Eureka lemon</td>
+      <td class="tdc">104</td>
+      <td class="tdc">32&nbsp;&#8199;</td>
+      <td class="tdc">0.12</td>
+      <td class="tdc">24.5</td>
+      <td class="tdc">&#8199;38</td>
+      <td class="tdc">2.08</td>
+      <td class="tdc">0.57</td>
+   </tr><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc"><b>Flesh</b></td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc"><b>Per cent</b></td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Apricot</td>
+      <td class="tdc">62.4</td>
+      <td class="tdc">93.85</td>
+      <td class="tdc">6.15</td>
+      <td class="tdc">10.0</td>
+      <td class="tdc">90.0</td>
+      <td class="tdc">13.31</td>
+      <td class="tdc">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Prune</td>
+      <td class="tdc">25.6</td>
+      <td class="tdc">94.2&#8199;</td>
+      <td class="tdc">5.8&#8199;</td>
+      <td class="tdc">21.2</td>
+      <td class="tdc">78.8</td>
+      <td class="tdc">20.0&#8199;</td>
+      <td class="tdc">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Plum</td>
+      <td class="tdc">60.4</td>
+      <td class="tdc">95.2&#8199;</td>
+      <td class="tdc">4.8&#8199;</td>
+      <td class="tdc">24.7</td>
+      <td class="tdc">75.3</td>
+      <td class="tdc">17.97</td>
+      <td class="tdc">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Peach</td>
+      <td class="tdc">185&nbsp;&#8199;</td>
+      <td class="tdc">93.8&#8199;</td>
+      <td class="tdc">6.2&#8199;</td>
+      <td class="tdc">22.5</td>
+      <td class="tdc">77.5</td>
+      <td class="tdc">17.0&#8199;</td>
+      <td class="tdc">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc"><b>Skin</b></td>
+      <td class="tdc"><b>Cores</b></td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Apple</td>
+      <td class="tdc">183</td>
+      <td class="tdc">17.0</td>
+      <td class="tdc">7.0</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">10.26‡</td>
+      <td class="tdc">1.53‡</td>
+   </tr><tr>
+      <td class="tdr_ws1" colspan="8">‡ In whole fresh fruit.&emsp;&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc" rowspan="2">Name.</th>
+      <th class="tdc" rowspan="2">Acid</th>
+      <th class="tdc bb" colspan="4">In whole fruit.</th>
+   </tr><tr>
+      <th class="tdc bl">Nitrogenous<br>bodies.</th>
+      <th class="tdc_bott">Water.</th>
+      <th class="tdc_bott">(C)</th>
+      <th class="tdc_bott br">Ash.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">&nbsp;</td>
+      <td class="tdc">&nbsp;per cent.&nbsp;</td>
+      <td class="tdc">&nbsp;per cent.&nbsp;</td>
+      <td class="tdc">&nbsp;per cent.&nbsp;</td>
+      <td class="tdc">&nbsp;per cent.&nbsp;</td>
+      <td class="tdc">&nbsp;per cent.&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Naval orange</td>
+      <td class="tdc">1.02</td>
+      <td class="tdc">1.31</td>
+      <td class="tdc">86.56</td>
+      <td class="tdc">13.04</td>
+      <td class="tdc">0.40</td>
+   </tr><tr>
+      <td class="tdl">Mediterranean sweet orange</td>
+      <td class="tdc">1.38</td>
+      <td class="tdc">0.96</td>
+      <td class="tdc">85.83</td>
+      <td class="tdc">13.06</td>
+      <td class="tdc">0.41</td>
+   </tr><tr>
+      <td class="tdl">St. Michael’s orange</td>
+      <td class="tdc">1.35</td>
+      <td class="tdc">1.43</td>
+      <td class="tdc">84.10</td>
+      <td class="tdc">15.42</td>
+      <td class="tdc">0.48</td>
+   </tr><tr>
+      <td class="tdl">Malta Blood orange</td>
+      <td class="tdc">1.61</td>
+      <td class="tdc">1.05</td>
+      <td class="tdc">84.50</td>
+      <td class="tdc">15.05</td>
+      <td class="tdc">0.45</td>
+   </tr><tr>
+      <td class="tdl">Eureka lemon</td>
+      <td class="tdc">7.66</td>
+      <td class="tdc">0.94</td>
+      <td class="tdc">85.99</td>
+      <td class="tdc">13.50</td>
+      <td class="tdc">0.51</td>
+   </tr><tr>
+      <td class="tdc" colspan="6">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Apricot</td>
+      <td class="tdc">0.68</td>
+      <td class="tdc">1.25</td>
+      <td class="tdc">85.16</td>
+      <td class="tdc">14.35</td>
+      <td class="tdc">0.49</td>
+   </tr><tr>
+      <td class="tdl">Prune</td>
+      <td class="tdc">0.40</td>
+      <td class="tdc">1.01</td>
+      <td class="tdc">77.38</td>
+      <td class="tdc">22.18</td>
+      <td class="tdc">0.44</td>
+   </tr><tr>
+      <td class="tdl">Plum</td>
+      <td class="tdc">0.48</td>
+      <td class="tdc">1.33</td>
+      <td class="tdc">77.43</td>
+      <td class="tdc">22.04</td>
+      <td class="tdc">0.53</td>
+   </tr><tr>
+      <td class="tdl">Peach</td>
+      <td class="tdc">0.25</td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">82.50</td>
+      <td class="tdc">16.95</td>
+      <td class="tdc">0.55</td>
+   </tr><tr>
+      <td class="tdc" colspan="6">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Apple<a id="FNanchor_585" href="#Footnote_585" class="fnanchor">[585]</a></td>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc">0.11</td>
+      <td class="tdc">86.43</td>
+      <td class="tdc">13.28</td>
+      <td class="tdc">0.29</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_580"></a>[Pg 580]</span>
+<b>575. Composition of Ash of Fruits.</b>—Two or three kilograms of
+the dried sample are incinerated at a low temperature and burned to
+a white ash in accordance with the directions given in
+paragraphs <b><a href="#P_28">28-32</a></b>.</p>
+
+<p>The composition of the ash is determined by the methods already
+described.<a id="FNanchor_586" href="#Footnote_586" class="fnanchor">[586]</a></p>
+
+<p>The pure ash of some common whole fruits has the following
+composition:<a id="FNanchor_587" href="#Footnote_587" class="fnanchor">[587]</a></p>
+
+<ul class="index">
+<li class="isub3"><b>(A)</b> = Per cent pure ash in fruit.</li>
+<li class="isub3"><b>(B)</b> = Per cent manganomanganic oxid.</li>
+<li class="isub3"><b>(C)</b> = Per cent phosphorus pentoxid.</li>
+<li class="isub3"><b>(D)</b> = Per cent sulfur trioxid.</li>
+</ul>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc_bott">Name.</th>
+      <th class="tdc_bott fs_110">&nbsp; (A) &nbsp;</th>
+      <th class="tdc">&nbsp;Per cent&nbsp;<br>potash.</th>
+      <th class="tdc">&nbsp;Per cent&nbsp;<br>soda.</th>
+      <th class="tdc">&nbsp;Per cent&nbsp;<br>lime.</th>
+      <th class="tdc">Per cent<br>&nbsp;magnesia.&nbsp;</th>
+      <th class="tdc">Per cent<br>&nbsp;ferric oxid.&nbsp;</th>
+      <th class="tdc_bott fs_110">&nbsp; (B) &nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Prune</td>
+      <td class="tdc">0.47</td>
+      <td class="tdc">63.83</td>
+      <td class="tdc">2.65</td>
+      <td class="tdc">4.66</td>
+      <td class="tdc">5.47</td>
+      <td class="tdc">2.72</td>
+      <td class="tdc">0.39</td>
+   </tr><tr>
+      <td class="tdl">Apricot</td>
+      <td class="tdc">0.51</td>
+      <td class="tdc">59.36</td>
+      <td class="tdc">10.26&#8199;</td>
+      <td class="tdc">3.17</td>
+      <td class="tdc">3.68</td>
+      <td class="tdc">1.68</td>
+      <td class="tdc">0.37</td>
+   </tr><tr>
+      <td class="tdl">Orange</td>
+      <td class="tdc">0.43</td>
+      <td class="tdc">48.94</td>
+      <td class="tdc">2.50</td>
+      <td class="tdc">22.71&#8199;</td>
+      <td class="tdc">5.34</td>
+      <td class="tdc">0.97</td>
+      <td class="tdc">0.37</td>
+   </tr><tr>
+      <td class="tdl">Lemon</td>
+      <td class="tdc">0.53</td>
+      <td class="tdc">48.26</td>
+      <td class="tdc">1.76</td>
+      <td class="tdc">29.87&#8199;</td>
+      <td class="tdc">4.40</td>
+      <td class="tdc">0.43</td>
+      <td class="tdc">0.28</td>
+   </tr><tr>
+      <td class="tdl">Apple</td>
+      <td class="tdc">1.44</td>
+      <td class="tdc">35.68</td>
+      <td class="tdc">26.09&#8199;</td>
+      <td class="tdc">4.08</td>
+      <td class="tdc">8.75</td>
+      <td class="tdc">1.40</td>
+      <td class="tdc">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Pear</td>
+      <td class="tdc">1.97</td>
+      <td class="tdc">54.69</td>
+      <td class="tdc">8.52</td>
+      <td class="tdc">7.98</td>
+      <td class="tdc">5.22</td>
+      <td class="tdc">1.04</td>
+      <td class="tdc">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Peach</td>
+      <td class="tdc">4.90</td>
+      <td class="tdc">27.95</td>
+      <td class="tdc">0.23</td>
+      <td class="tdc">8.81</td>
+      <td class="tdc">17.66&#8199;</td>
+      <td class="tdc">0.55</td>
+      <td class="tdc">&nbsp;</td>
+   </tr><tr>
+      <td class="tdc" colspan="8">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl"><b>Name.</b></td>
+      <td class="tdc"><b>(C)</b></td>
+      <td class="tdc"><b>(D)</b></td>
+      <td class="tdc"><b>Per cent<br>silica.</b></td>
+      <td class="tdc"><b>Per cent<br>chlorin.</b></td>
+      <td class="tdc" rowspan="8" colspan="3">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Prune</td>
+      <td class="tdc">14.08</td>
+      <td class="tdc">2.68</td>
+      <td class="tdc">3.07</td>
+      <td class="tdc">0.34</td>
+   </tr><tr>
+      <td class="tdl">Apricot</td>
+      <td class="tdc">13.09</td>
+      <td class="tdc">2.63</td>
+      <td class="tdc">5.23</td>
+      <td class="tdc">0.45</td>
+   </tr><tr>
+      <td class="tdl">Orange</td>
+      <td class="tdc">12.37</td>
+      <td class="tdc">5.25</td>
+      <td class="tdc">0.65</td>
+      <td class="tdc">0.92</td>
+   </tr><tr>
+      <td class="tdl">Lemon</td>
+      <td class="tdc">11.09</td>
+      <td class="tdc">2.84</td>
+      <td class="tdc">0.66</td>
+      <td class="tdc">0.39</td>
+   </tr><tr>
+      <td class="tdl">Apple</td>
+      <td class="tdc">13.59</td>
+      <td class="tdc">6.09</td>
+      <td class="tdc">4.32</td>
+      <td class="tdc" rowspan="3">&nbsp;</td>
+   </tr><tr>
+      <td class="tdl">Pear</td>
+      <td class="tdc">15.20</td>
+      <td class="tdc">5.69</td>
+      <td class="tdc">1.49</td>
+   </tr><tr>
+      <td class="tdl">Peach</td>
+      <td class="tdc">43.63</td>
+      <td class="tdc">0.37</td>
+      <td class="tdc">&nbsp;</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>576. Dried Fruits.</b>—A method of preserving fruits largely
+practiced consists in subjecting them, in thin slices or whole, to
+the action of hot air until the greater part of the moisture is
+driven off. The technique of the process is fully described in recent
+publications.<a id="FNanchor_588" href="#Footnote_588" class="fnanchor">[588]</a>
+It has been shown by Richards that fruit subjected to rapid evaporation
+undergoes but little change aside from the loss of water.<a id="FNanchor_589" href="#Footnote_589" class="fnanchor">[589]</a></p>
+
+<p>In the analyses of dried fruits the methods already described are used.
+The presence of pectin renders the filtration of the aqueous extract
+somewhat difficult, and in many cases it is advisable to determine the
+sugars present in the extract without previous filtration.</p>
+
+<p><b>577. Zinc in Evaporated Fruits.</b>—Fruits are commonly evaporated
+on trays made of galvanized iron. In these instances a portion of
+the zinc is dissolved by the fruit acids, and will be found as zinc
+malate etc., in the finished product. The presence of zinc salts is
+objectionable for hygienic reasons, and therefore the employment of
+<span class="pagenum"><a id="Page_581"></a>[Pg 581]</span>
+galvanized trays should be discontinued. The presence of zinc in
+evaporated fruits may be detected by the following process.<a id="FNanchor_590" href="#Footnote_590" class="fnanchor">[590]</a>
+The sample is placed in a large platinum dish and heated slowly until dry
+and in incipient combustion. The flame is removed and the combustion
+allowed to proceed, the lamp being applied from time to time in case
+the burning ceases. When the mass is burned out it will be found
+to consist of ash and char, which are ground to a fine powder and
+extracted with hydrochloric or nitric acid. The residual char is burned
+to a white ash at a low temperature, the ash extracted with acid, the
+soluble portion added to the first extract and the whole filtered.
+The iron in the filtrate is oxidized by boiling with bromin water and
+the boiling continued until the excess of bromin is removed. A drop
+of methyl orange is placed in the liquid and ammonia added until it
+is only faintly acid. The iron is precipitated by adding fifty cubic
+centimeters of a solution containing 250 grams of ammonium acetate in
+a liter and raising the temperature to about 80°. The precipitate is
+separated by filtration and washed with water at 80° until free of
+chlorids. The filtrate is saturated with hydrogen sulfid, allowed to
+stand until the zinc sulfid settles and poured on a close filter. It is
+often necessary to return the filtrate several times before it becomes
+limpid. The collected precipitate is washed with a saturated solution
+of hydrogen sulfid containing a little acetic acid. The precipitate
+and filter are transferred to a crucible, dried, ignited and the zinc
+weighed as oxid. Small quantities of zinc salts added to fresh apples
+which were dried and treated as above described, were recovered by this
+method without loss. Other methods of estimating zinc in dried fruits
+are given in the bulletin cited.</p>
+
+<p>Evaporated apples contain a mean content of 23.85 per cent of water and
+0.931 per cent of ash.</p>
+
+<p>The mean quantity of zinc oxid found in samples of apples dried in
+the United States is ten milligrams for each 100 grams of the fruit,
+an amount entirely too small to produce any toxic effects. When zinc
+exists in the soil it will be found as a natural constituent in the
+crop.<a id="FNanchor_591" href="#Footnote_591" class="fnanchor">[591]</a></p>
+
+<p><b>578. Composition of Watermelons and Muskmelons.</b>—In the
+examination of melons a separation of the rind, seeds and meat is
+<span class="pagenum"><a id="Page_582"></a>[Pg 582]</span>
+somewhat difficult of accomplishment, since the line of demarcation is
+not distinct. In watermelons the separation of rind and meat is made
+at the point where the red color of the meat disappears. In muskmelons
+no such definite point is found and in the examination of these they
+are taken as a whole. The total moisture, ash and nitrogen may be
+determined in the whole mass or in the separate portions. The sugars
+are most conveniently determined in the expressed juices. The mean
+composition of the melons given below is that obtained from analyses
+made in the Department of Agriculture.<a id="FNanchor_592" href="#Footnote_592" class="fnanchor">[592]</a></p>
+
+<table class="spb1 spa1">
+   <thead><tr>
+      <th class="tdc fs_120" colspan="5"><span class="smcap">Composition of Melons.</span></th>
+   </tr><tr>
+      <th class="tdc">&nbsp;</th>
+      <th class="tdc bb">Total weight,<br>grams.</th>
+      <th class="tdc bb">Juice,<br>per cent.</th>
+      <th class="tdc bb">Total<br>proteids,<br>per cent.</th>
+      <th class="tdc bb">Ash,<br>per cent.</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc" rowspan="2">Watermelons</td>
+      <td class="tdc" rowspan="2">10330</td>
+      <td class="tdc">meat 83.99</td>
+      <td class="tdc" rowspan="2">6.12</td>
+      <td class="tdc" rowspan="2">0.37</td>
+   </tr><tr>
+      <td class="tdc">rind 81.02</td>
+   </tr><tr>
+      <td class="tdc">Muskmelons</td>
+      <td class="tdc">3407</td>
+      <td class="tdr">80.23</td>
+      <td class="tdc">6.45</td>
+      <td class="tdc">0.57</td>
+   </tr><tr>
+      <td class="tdc fs_120" colspan="5"><b><span class="smcap">&nbsp;<br>Composition of Juice.</span></b></td>
+   </tr><tr>
+      <td class="tdc">&nbsp;</td>
+      <td class="tdc_bott bb"><b>Sucrose<br>in juice,<br>per cent.</b></td>
+      <td class="tdc bb" colspan="2"><b>Reducing<br> sugars<br>in juice,<br>per cent.</b></td>
+      <td class="tdc_bott bb"><b>Ash<br>per cent.</b></td>
+   </tr><tr>
+      <td class="tdc" rowspan="2">Watermelons</td>
+      <td class="tdc">meat  1.92</td>
+      <td class="tdc" colspan="2">meat 4.33</td>
+      <td class="tdc">meat  0.31</td>
+   </tr><tr>
+      <td class="tdc">rind  0.34</td>
+      <td class="tdc" colspan="2">rind 2.47</td>
+      <td class="tdc">rind  0.38</td>
+   </tr><tr>
+      <td class="tdc">Muskmelons</td>
+      <td class="tdr_ws1">1.02</td>
+      <td class="tdc" colspan="2">&#8199;&#8199;&#8199;3.04</td>
+      <td class="tdr">0.53</td>
+   </tr>
+ </tbody>
+</table>
+
+<h3>TEA AND COFFEE.</h3>
+
+<p><b>579. Special Analysis.</b>—Aside from the examination of teas and
+coffees for adulterants, the only special determinations which are
+required in analyses are the estimation of the alkaloid (caffein) and
+of the tannin contained therein. It is chiefly to the alkaloid that the
+stimulating effects of the beverages made from tea and coffee are due.
+The determination of the quantity of tannin contained in tea and coffee
+is accomplished by the processes described under the chapter devoted to
+that glucosid.</p>
+
+<p>The general analysis, <i>viz.</i>, the estimation of water, ether
+extract, total nitrogen, fiber, carbohydrates and ash, with the
+exceptions noted above, is conducted by the methods which have already
+been given.</p>
+
+<p>For detailed instructions concerning the detection of adulterants of
+tea and coffee the bulletins of the Chemical Division, Department of
+Agriculture, may be consulted.<a id="FNanchor_593" href="#Footnote_593" class="fnanchor">[593]</a></p>
+
+<p><span class="pagenum"><a id="Page_583"></a>[Pg 583]</span>
+<b>580. Estimation of Caffein</b> (<b>Thein</b>).—The method adopted
+by Spencer, after a thorough trial of all the usual processes for
+estimating this alkaloid, is as follows:<a id="FNanchor_594" href="#Footnote_594" class="fnanchor">[594]</a>
+To three grams of the finely powdered tea or coffee, in a 300 cubic
+centimeter flask, add about a quarter of a liter of water, slowly heat
+to the boiling point, using a fragment of tallow to prevent frothing,
+and boil gently for half an hour. When boiling begins, the flask should
+be nearly filled with hot water and more added from time to time to
+compensate for the loss due to evaporation. After cooling, add a
+strong solution of basic lead acetate until no further precipitation
+is produced, complete the volume to the mark with water, mix and throw
+on a filter. Precipitate the lead from the filtrate by hydrogen sulfid
+and filter. Boil a measured volume of this filtrate to expel the excess
+of hydrogen sulfid, cool and add sufficient water to compensate for
+the evaporation. Transfer fifty cubic centimeters of this solution to
+a separatory funnel and shake seven times with chloroform. Collect the
+chloroform solution in a tared flask and remove the solvent by gentle
+distillation. A safety bulb, such as is used in the kjeldahl nitrogen
+method, should be employed to prevent entrainment of caffein with the
+chloroform vapors.</p>
+
+<p>The extraction with chloroform is nearly complete after shaking out
+four times; a delicate test, however, will usually reveal the presence
+of caffein in the watery residue even after five or six extractions,
+hence seven extractions are recommended for precautionary reasons. The
+residual caffein is dried at 75° for two hours and weighed.</p>
+
+<p>The principal objection which has been made to Spencer’s method is
+that the boiling with water is not continued for a sufficient length
+of time. For the water extraction, Allen prescribes at least six hours
+cohobation.<a id="FNanchor_595" href="#Footnote_595" class="fnanchor">[595]</a>
+In this method six grams of the powdered substance are boiled with
+half a liter of water for six hours in a flask, with a condenser, the
+decoction filtered, the volume of the filtrate completed to 600 cubic
+centimeters with the wash water, heated to boiling, and four cubic
+centimeters of strong lead acetate solution added, the mixture boiled
+for ten minutes, filtered and half a liter of the filtrate evaporated
+<span class="pagenum"><a id="Page_584"></a>[Pg 584]</span>
+to fifty cubic centimeters. The excess of lead is removed with sodium
+phosphate and the filtrate and washings concentrated to about forty
+cubic centimeters. The caffein is removed by shaking four times with
+chloroform. Older but less desirable processes are fully described by
+Allen.<a id="FNanchor_596" href="#Footnote_596" class="fnanchor">[596]</a></p>
+
+<p>In France this method is known as the process of Petit and Legrip, and
+it has been worked out in great detail by Grandval and Lajoux and by
+Petit and Terbat.<a id="FNanchor_597" href="#Footnote_597" class="fnanchor">[597]</a></p>
+
+<p><b>581. Estimation of Caffein by Precipitation with Iodin.</b>—The
+caffein in this method is extracted, the extract clarified by lead
+acetate and the excess of lead removed as in Spencer’s process
+described above. The caffein is determined in the acidified aqueous
+solution thus prepared, according to the plan proposed by Gomberg, as
+follows:<a id="FNanchor_598" href="#Footnote_598" class="fnanchor">[598]</a></p>
+
+<p>Definite volumes of the aqueous solution of the caffein are acidulated
+with sulfuric and the alkaloid precipitated by an excess of a set
+solution of iodin in potassium iodid. After filtering, the excess of
+iodin in an aliquot part of the filtrate is determined by titration
+with a tenth normal solution of sodium thiosulfate. The filtration
+of the iodin liquor is accomplished on glass wool or asbestos. The
+results of the analyses are calculated from the composition of the
+precipitated caffein periodid; <i>viz.</i>, <b>C₈H₁₀N₄O₂.HI.I₄</b>. The weight
+of the alkaloid is calculated from the amount of iodin required for the
+precipitation by the equation <b>4I: C₈H₁₀N₄O₂ = 508: 194</b>. From this
+equation it is shown that one part of iodin is equivalent to 0.3819
+part of caffein, or one cubic centimeter of tenth normal iodin solution
+is equal to 0.00485 gram of iodin.</p>
+
+<p>In practice, it is recommended to divide the aqueous extract of the
+alkaloid, prepared as directed above, into two portions, one of which
+is treated with the iodin reagent without further preparation, and
+the other after acidulation with sulfuric. After ten minutes, the
+residual iodin is estimated in each of the solutions as indicated
+above. The one portion, containing only the acetic acid resulting from
+the decomposition of the lead acetate, serves to indicate whether
+the aqueous solution of the caffein contains other bodies than that
+alkaloid capable of forming a precipitate with the reagent, since the
+caffein itself is not precipitated even in presence of strong acetic acid.
+<span class="pagenum"><a id="Page_585"></a>[Pg 585]</span></p>
+
+<p>In the solution acidulated with sulfuric, the caffein, together with
+the other bodies capable of combining with iodin, is precipitated. The
+residual iodin is determined in each case, and thus the quantity which
+is united with the caffein is easily ascertained. The weight of iodin
+which has entered into the precipitated caffein periodid multiplied by
+0.3819 gives the weight of the caffein in the solution.</p>
+
+<p>Gomberg’s method has been subjected to a careful comparative study by
+Spencer and has been much improved by him in important particulars.<a id="FNanchor_599" href="#Footnote_599" class="fnanchor">[599]</a></p>
+
+<p>It is especially necessary to secure the complete expulsion of
+the hydrogen sulfid and to observe certain precautions in the
+addition of the iodin reagent. The precipitation should be made in a
+glass-stoppered flask, shaking thoroughly after the addition of the
+iodin and collecting the precipitate on a gooch. As thus modified, the
+iodin process gives results comparable with those obtained by Spencer’s
+method, and it can also be used to advantage in estimating caffein in
+headache tablets in the presence of acetanilid.</p>
+
+<p><b>582. Freeing Caffein of Chlorophyll.</b>—Any chlorophyll which
+may pass into solution and be found in the caffein may be removed
+by dissolving the caffein in ten per cent sulfuric acid, filtering,
+neutralizing with ammonia and evaporating to dryness. The residue is
+taken up with chloroform, the chloroform removed at a low temperature
+and the pure caffein thus obtained.<a id="FNanchor_600" href="#Footnote_600" class="fnanchor">[600]</a></p>
+
+<p><b>583. Proteid Nitrogen.</b>—The proteid nitrogen in tea and coffee
+may be determined in the residue after extraction of the alkaloid
+by boiling water as described above. More easily it is secured by
+determining the total nitrogen in the sample and deducting therefrom
+the nitrogen present as caffein. The remainder, multiplied by 6.25,
+will give the quantity of proteid matter.</p>
+
+<p><b>584. Carbohydrates of the Coffee Bean.</b>—The carbohydrates of the
+coffee bean include those common to vegetable substances; <i>viz.</i>,
+cellulose, pentosan bodies (xylan, araban), fiber etc., together
+with certain sugars, of which sucrose is pointed out by Ewell as the
+chief.<a id="FNanchor_601" href="#Footnote_601" class="fnanchor">[601]</a>
+In smaller quantities are found a galactose yielding body (galactan),
+as pointed out by Maxwell, a dextrinoid and a trace of a sugar reducing
+<span class="pagenum"><a id="Page_586"></a>[Pg 586]</span>
+alkaline copper solution.</p>
+
+<p>The sucrose may be separated from the coffee bean by the following
+process:<a id="FNanchor_602" href="#Footnote_602" class="fnanchor">[602]</a>
+The finely ground flour is extracted with seventy per cent alcohol, the
+extract clarified with lead acetate, filtered, the lead removed from
+the filtrate with hydrogen sulfid, the excess of the gas removed by
+boiling, the filtrate evaporated in a partial vacuum to a sirup and the
+sucrose crystallized from a solution of the sirup in alcohol.</p>
+
+<p>For a quantitive determination, ten grams of the coffee flour are
+extracted with ether and the residue with seventy-five per cent
+alcohol. This process, conducted in a continuous extraction apparatus,
+should be continued for at least twenty-four hours. The alcohol is
+removed by evaporation, the residue dissolved in water, clarified with
+basic lead acetate, filtered, the precipitate washed, the lead removed,
+again filtered, the filtrate washed and wash water and filtrate made to
+a definite volume. In an aliquot part of this solution the sugars
+are determined by the alkaline copper method, both before and after
+inversion. From the data obtained the percentage of sucrose is calculated.</p>
+
+<p>In a coffee examined by Ewell the percentage of sucrose was found to be
+6.34. The pentose yielding constituents of the coffee bean amount to
+from eight to ten per cent.</p>
+
+<p>When coffee meal is extracted with a five per cent solution of sodium
+carbonate, a gummy substance is obtained, which is precipitable by
+alcohol. This gum, after washing with hydrochloric acid containing
+alcohol, gives a gray, translucent, hard mass on drying. On hydrolysis
+it yielded 75.2 per cent of dextrose, on distillation with hydrochloric
+acid, thirteen per cent of furfuraldehyd and, on oxidation with nitric
+acid, 18.7 per cent of mucic acid. This gum, therefore, consists
+chiefly of a mixture of galactan, xylan and araban.</p>
+
+<p id="P_585"><b>585. Estimation of Galactan.</b>—From three to five grams of the
+substance supposed to contain galactan are placed in a beaker with
+sixty cubic centimeters of nitric acid of 1.15 specific gravity. The
+mixture is evaporated on a steam bath until it is reduced to one-third
+<span class="pagenum"><a id="Page_587"></a>[Pg 587]</span>
+of its original volume, allowed to stand for twenty-four hours, ten
+cubic centimeters of water added, well stirred and again allowed
+to stand for twenty-four hours, until the mucic acid is separated
+in a crystalline form. To remove impurities from the mucic acid it
+is separated by filtration, washed with not to exceed twenty cubic
+centimeters of water, placed together with the filter in the beaker,
+from twenty-five to thirty cubic centimeters of ammonium carbonate
+solution, containing one part of dry ammonium carbonate, nineteen
+parts of water and one part of ammonium hydroxid, added and heated to
+near the boiling point. The mucic acid is dissolved by the ammonium
+carbonate solution and any insoluble impurity separated by filtration,
+the filtrate being received in a platinum dish, the residue well washed
+and the entire filtrate and wash water evaporated to dryness on a steam
+bath acidified with dilute nitric, well stirred and allowed to stand
+until the mucic acid separates in a crystalline form. The separation
+is usually accomplished in half an hour, after which time the crystals
+of mucic acid are collected on a tared filter, or gooch, and washed
+with not to exceed fifteen cubic centimeters of water followed with
+sixty cubic centimeters of alcohol, then with ether, dried at 100°
+and weighed. For computing the amount of galactose, one gram of the
+mucic acid is equal to 1.333 of galactose and one gram of galactose is
+equal to nine-tenths gram of galactan. Before the commencement of the
+operation, the material should be freed of fatty matters in the case of
+oily seeds and other substances similar thereto.<a id="FNanchor_603" href="#Footnote_603" class="fnanchor">[603]</a></p>
+
+<p id="P_586"><b>586. Revised Factors for Pentosans.</b>—The factors given in
+paragraph <b><a href="#P_154">154</a></b> have lately been recalculated by Mann,
+Kruger and Tollens, and as a result of their investigations the following factors
+are now recommended.<a id="FNanchor_604" href="#Footnote_604" class="fnanchor">[604]</a>
+The quantity of furfurol is derived from the weight of furfurolhydrazone
+obtained by the formula:</p>
+
+<ul class="index fs_105">
+<li class="isub3">1. Furfurolhydrazone × 0.516 + 0.0104 = furfurol.</li>
+<li class="isub3">2. Furfurol × 1.84 = pentosans.</li>
+<li class="isub3">3. Furfurol × 1.64 = xylan.</li>
+<li class="isub3">4. Furfurol × 2.02 = araban.</li>
+</ul>
+
+<p>The pentoses (xylose, arabinose) may be calculated from the pentosans
+(xylan, araban) by dividing by 0.88.
+<span class="pagenum"><a id="Page_588"></a>[Pg 588]</span></p>
+
+<p>The method of procedure preferred for the estimation of the pentosans
+is that described in paragraph <b><a href="#P_157">157</a></b>. The phloroglucin
+is dissolved in hydrochloric acid of 1.06 specific gravity before it is
+added to the furfurol distillate. The latest factor for converting
+the phloroglucid obtained into furfurol is to divide by 1.82 for
+small quantities and 1.93 for large quantities. After the furfurol is
+obtained, the factors given above are applied.</p>
+
+<p><b>587. Application of Roentgen Rays to Analysis.</b>—The detection
+of mineral matters in vegetable substances by roentgen photography has
+been proposed by Ranvez.<a id="FNanchor_605" href="#Footnote_605" class="fnanchor">[605]</a>
+This process will prove extremely valuable in detecting the lacing
+of teas with mineral substances. Practically, it has been applied by
+Ranvez in the detection of mineral substances mixed with saffron with
+fraudulent intent.</p>
+
+<p>Barium sulfate is often mixed with saffron for the purpose of
+increasing its weight. Pure saffron and adulterated samples are
+enclosed in capsules of black paper and exposed on the same sensitive
+plate for a definite time to the rays emanating from a crookes tube.
+In this case the pure saffron forms only a very faint shadow in the
+developed negative, while the parts to which barium sulfate are
+attached produce strong shadows. The principle involved is applicable
+to a wide range of analytical research.</p>
+
+<h3>TANNINS AND ALLIED BODIES.</h3>
+
+<p><b>588. Occurrence and Composition.</b>—The tannins and allied bodies,
+which are of importance in this connection, are those which occur in
+food products and beverages and also those made use of in the leather
+industry. The term tannin is applied to a large class of astringent
+substances, many of which are glucosids. Tannic acid is the chief
+constituent of the tannins, and is found in a state of comparative
+purity in nutgalls. The source from which the tannic acid is derived
+is indicated by a prefix to the name, <i>e. g.</i>, gallotannic, from
+nutgalls, and caffetannic, from coffee etc. The tannins have lately
+been the theme of a critical study by Trimble, and the reader is
+referred to his work for an exhaustive study of the subject.<a id="FNanchor_606" href="#Footnote_606" class="fnanchor">[606]</a>
+Tannin is one of the most widely diffused compounds, occurring in hundreds
+<span class="pagenum"><a id="Page_589"></a>[Pg 589]</span>
+of plants. Commercially, the oaks and hemlocks are the most important
+plants containing tannin. The sumach, mangrove, canaigre, palmetto and
+many others have also been utilized as commercial sources of tannin.
+The tannins as a class are amorphous and odorless. They are slightly
+acid and strongly astringent. Their colors vary from dark brown to
+pure white. They are soluble in water, alcohol, ether and glycerol and
+insoluble in chloroform, benzol, petroleum ether, carbon bisulfid and
+the oils. The tannins give blue or green precipitates with iron salts
+and most of them brown precipitates with potassium bichromate. They are
+all precipitated by gelatin or albumin. Tannins are not only generally
+of a glucosidal nature, but are found quite constantly associated with
+reducing sugars, or in unstable combination therewith.</p>
+
+<p>The reducing sugars may be separated from the tannin by precipitating
+the latter with lead acetate and determining the glucose in the
+filtrate after the removal of the lead. A separate portion of the
+tannin is hydrolyzed with sulfuric or hydrochloric acid and the
+reducing sugars again determined. Any excess of sugars over the first
+determination is due to the hydrolysis of the tannin glucosid.</p>
+
+<p id="P_589"><b>589. Detection and Estimation of Tannins.</b>—The qualitive
+reactions above mentioned serve to detect the presence of a tannin. Of
+the iron salts ferric acetate or chlorid is preferred. Ferrous salts
+do not give any reaction with dilute tannin solutions. An ammoniacal
+solution of potassium ferricyanid forms with tannins a deep red color
+changing to brown. In quantitive work the tannins are mostly determined
+by precipitation with metallic salts, by treatment with gelatin or hide
+powder, or by oxidation with potassium permanganate. Directions for the
+estimation of glucosids in general are found in Dragendorff’s book.<a id="FNanchor_607" href="#Footnote_607" class="fnanchor">[607]</a></p>
+
+<p><b>590. Precipitation with Metallic Salts.</b>—The methods depending
+on precipitation of the tannins with metallic salts are but little
+used and only one of them will be mentioned here. A full description
+of the others is contained in Trimble’s book.<a id="FNanchor_608" href="#Footnote_608" class="fnanchor">[608]</a>
+A method for the determination of caffetannic acid in coffee has been
+<span class="pagenum"><a id="Page_590"></a>[Pg 590]</span>
+worked out by Krug and used with some satisfaction.<a id="FNanchor_609" href="#Footnote_609" class="fnanchor">[609]</a></p>
+
+<p>In this method two grams of the coffee meal are digested for thirty-six
+hours with ten cubic centimeters of water, a little more than twice
+that volume of ninety-five per cent alcohol added and the digestion
+continued for a day. The contents of the flask are poured on a filter
+and the residue washed with alcohol. The filtrate contains tannin,
+caffetannic acid and traces of coloring matter and fat. It is heated
+to the boiling point and clarified with a solution of lead acetate.
+A caffetannate of lead containing forty-nine per cent of the metal
+is precipitated. As soon as the precipitate has become flocculent it
+is collected on a filter, washed with ninety per cent alcohol until
+the soluble lead salts are all removed, then with ether and dried.
+The composition of the precipitate is represented by the formula
+<b>Pb₃(C₁₅H₁₅O₈)₂</b>. The caffetannic acid is calculated by the equation:
+Weight of precipitate: weight of caffetannic acid = 1267: 652.</p>
+
+<p><b>591. The Gelatin Method.</b>—The precipitation of tannin with
+gelatin is the basis of a process for its quantitive estimation which,
+according to Trimble, is conducted as follows:<a id="FNanchor_610" href="#Footnote_610" class="fnanchor">[610]</a>
+Two and a half grams of gelatin and ten grams of alum are dissolved
+in water and the volume of the solution made up to one liter. The
+solution of gelatin and also that of the tannin are heated to 70° and
+the tannin is precipitated by adding the gelatin reagent slowly, with
+constant stirring, until the precipitate coagulates, and, on settling,
+leaves a clear liquor in which no further precipitate is produced on
+adding a few drops more of the reagent. In case the clearing of the
+mixture do not take place readily, the process should be repeated with
+a more dilute tannin solution. The precipitate is collected on two
+counterpoised filter papers one placed inside the other, dried at 110°
+and weighed, the empty filter paper being placed on the pan with the
+weights. For pure tannin (gallotannic acid) fifty-four per cent of the
+weight of the precipitate are tannin. Ammonium chlorid and common salt
+have been used in place of the alum in preparing the reagent, but if
+the proportion of alum mentioned above be used, satisfactory results
+will be obtained in most cases.
+<span class="pagenum"><a id="Page_591"></a>[Pg 591]</span></p>
+
+<p><b>592. The Hide Powder Method.</b>—The principle of this method is
+based on the change in specific gravity, <i>i. e.</i>, total solids,
+which a tannin solution will undergo when brought into contact with
+raw hides in a state of fine subdivision. The hide powder absorbs the
+tannin, and the total solid content of the solution is correspondingly
+diminished. The method is conducted according to the official
+directions as follows:<a id="FNanchor_611" href="#Footnote_611" class="fnanchor">[611]</a></p>
+
+<p><i>Preparation of the Sample.</i>—The bark, wood, leaves or other
+materials holding the tannins, are dried and ground to a fine powder
+and thoroughly extracted with water as mentioned below. In each case
+the solution or extraction is made as thorough as possible and the
+volume of the extract is made up to a definite amount.</p>
+
+<p><i>Quantity of Tanning Material.</i>—Use such an amount of the tanning
+material as shall give in 100 cubic centimeters of the filtered
+solution about one gram of dry solids. In the case of barks, woods,
+leaves and similar materials, transfer to a half liter flask, fill
+the flask with water at approximately 80° and let stand over night in
+a bath which is kept at 80°, cool, fill to the mark, shake well and
+filter. In the case of extracts and sweet liquors, wash the proper
+quantity into a half liter flask with water at approximately 80°,
+almost filling the flask, cool and fill to the mark.</p>
+
+<p><i>Determination of Moisture.</i>—Dry five grams of the sample in a
+flat bottom dish at the temperature of boiling water until the weight
+becomes constant.</p>
+
+<p><i>Determination of Total Solids.</i>—Shake the solution, which should
+be at a temperature of about 20°, and immediately remove 100 cubic
+centimeters with a pipette, evaporate in a weighed dish and dry to
+constant weight at the temperature of boiling water.</p>
+
+<p><i>Determination of Soluble Solids.</i>—Filter a portion of the
+solution through a folded filter, returning the filtrate to the filter
+twice and adding a teaspoonful of kaolin, if necessary. Evaporate 100
+cubic centimeters of the filtrate and dry as above.</p>
+
+<p><i>Determination of Tanning Substances.</i>—Extract twenty grams of
+hide powder by shaking for five minutes with 250 cubic centimeters of
+water, filter through well washed muslin or linen, repeat the operation
+three times and dry as much as possible in a suitable press. Weigh the
+<span class="pagenum"><a id="Page_592"></a>[Pg 592]</span>
+wet powder and determine the residual moisture in about one-fourth
+of the whole by drying to constant weight at 100°. Shake 200 cubic
+centimeters of the unfiltered solution of the tannin with the rest
+of the moist hide powder for about five minutes, add five grams of
+barium sulfate, shake for one minute and filter through a schleicher
+and schüll folded filter, No. 590, fifteen centimeters in diameter,
+returning the first twenty-five cubic centimeters of the filtrate.
+Evaporate 100 cubic centimeters of the clear filtrate and dry the
+residue to constant weight at a temperature of boiling water. The
+difference between the soluble solids obtained in the filtered tannin
+solution and the residue as obtained above is the amount of tanning
+material absorbed by the hide powder. This weight must be corrected for
+the water retained by the hide powder. The shaking must be conducted
+by means of a mechanical shaker, in order to remove all the tannin
+substance from the solution. The simple machine used by druggists, and
+known as the milkshake, is recommended.</p>
+
+<p><i>Testing the Hide Powder.</i>—Shake ten grams of the hide powder
+with 200 cubic centimeters of water for five minutes, filter through
+muslin or linen, squeeze out thoroughly by hand, replace the residue
+in the flask and repeat the operation twice with the same quantity of
+water. Pass the last filtrate through paper until a perfectly clear
+liquid is obtained. Evaporate 100 cubic centimeters of the final
+filtrate in a weighed dish, dry at 100° until the weight is constant.
+If the residue amount to more than ten milligrams the sample should be
+rejected. The hide powder must be kept in a dry place and tested once a
+month.</p>
+
+<p>Prepare a solution of pure gallotannic acid by dissolving five grams in
+one liter of water. Determine the total solids by evaporating 100 cubic
+centimeters of this solution and drying to constant weight. Treat 200
+cubic centimeters of the solution with hide powder exactly as described
+above. The hide powder must absorb at least ninety-five per cent of
+the total solids present. The gallotannic acid used must be completely
+soluble in water, alcohol, acetone and acetic ether and should contain
+not more than one per cent of substances not removed by digesting with
+excess of yellow mercuric oxid on the steam bath for two hours.
+<span class="pagenum"><a id="Page_593"></a>[Pg 593]</span></p>
+
+<p><i>Testing the Non-Tannin Filtrate. For Tannin</i>:—Test a small
+portion of the clear non-tannin filtrate with a few drops of a ten
+per cent solution of gelatin. A cloudiness indicates the presence
+of tannin, in which case the determination must be repeated, using
+twenty-five grams of hide powder instead of twenty grams.</p>
+
+<p><i>For Soluble Hide</i>:—To a small portion of the clear non-tannin
+filtrate, add a few drops of the original solution, previously filtered
+to remove reds. A cloudiness indicates the presence of soluble hide
+due to incomplete washing of the hide powder. In this case, repeat the
+determination with perfectly washed hide powder.</p>
+
+<p><b>593. The Permanganate Gelatin Method.</b>—This process, which is
+essentially the method of Löwenthal, as improved by Councler, Schroeder
+and Proctor and as used by Spencer for the determination of tannin in
+teas, is conducted as described below.<a id="FNanchor_612" href="#Footnote_612" class="fnanchor">[612]</a>
+The principle of the process is based on the oxidation of all bodies
+in solution oxidizable by potassium permanganate, the subsequent
+precipitation of the tannin by a gelatin solution, and the final
+oxidation, by means of permanganate, of the remaining organic bodies.
+The difference between the total oxidizable matter and that left after
+the precipitation of the tannin represents the tannin originally in solution.</p>
+
+<p><i>Reagents Required.</i>—The following reagents are necessary to the
+proper conduct of the potassium permanganate process:</p>
+
+<p>(1). Potassium permanganate solution containing about one and a third
+grams of the salt in a liter:</p>
+
+<p>The potassium permanganate solution is set by titration against the
+decinormal oxalic acid solution mentioned below. The end reaction with
+the indicator must be of the same tint in all the titrations, <i>i.
+e.</i>, either golden yellow or pink.</p>
+
+<p>(2). Tenth-normal oxalic acid solution for determining the exact titer
+of the permanganate solution:</p>
+
+<p>(3). Indigo-carmin solution to be used as an indicator and containing
+six grams of indigo-carmin and fifty cubic centimeters of sulfuric acid in
+a liter. The indigo-carmin must be very pure and quite free of indigo-blue.
+<span class="pagenum"><a id="Page_594"></a>[Pg 594]</span></p>
+
+<p>(4). Gelatin solution, prepared by digesting twenty-five grams of
+gelatin at room temperature for one hour in a saturated solution of
+sodium chlorid, then heating until solution is complete, cooling and
+making the volume up to one liter:</p>
+
+<p>(5). A salt acid solution, made by adding to 975 cubic centimeters of
+a saturated solution of sodium chlorid, enough strong sulfuric acid to
+bring the volume of the mixture to one liter:</p>
+
+<p>(6). Powdered kaolin for promoting filtration.</p>
+
+<p><i>The Process.</i>—Five grams of the finely powdered tea (or other
+vegetable substance containing tannin) are boiled with distilled water
+in a flask of half a liter capacity for half an hour. The distilled
+water should be at room temperature when poured over the powdered tea.
+After cooling, the volume of the decoction is completed to half a
+liter, and the contents of the flask poured on a filter. To ten cubic
+centimeters of the filtered tea infusion are added two and a half times
+as much of the indigo-carmin solution and about three-quarters of a
+liter of distilled water.</p>
+
+<p>The permanganate solution is run in from a burette, a little at a time,
+with vigorous stirring, until the color changes to a light green, and
+then drop by drop until the final color selected for the end of the
+reaction, golden yellow or faint pink, is obtained. The number of cubic
+centimeters of permanganate required is noted and represented by a in
+the formula below. The titration should be made in triplicate and the
+mean of the two more nearly agreeing readings taken as the correct one.</p>
+
+<p>One hundred cubic centimeters of the filtered tea infusion, obtained
+as directed above, are mixed with half that quantity of the gelatin
+reagent, the first named quantity of the acid salt solution added,
+together with ten grams of the powdered kaolin, the mixture well
+shaken for several minutes and poured on a filter. Twenty-five cubic
+centimeters of the filtrate, corresponding to ten of the original
+tea solution are titrated with the permanganate reagent, under the
+conditions given above, and the reading of the burette made and
+represented by <i>b</i>. The quantity of permanganate solution,
+<i>viz.</i>, <i>c</i>, required to oxidize the tannin is calculated
+from the formula <i>a - b</i> = <i>c</i>. The relation between the
+permanganate, oxalic acid and tannin is such that 0.04157 gram of
+gallotannic acid is equivalent to 0.063 gram of oxalic acid. The
+<span class="pagenum"><a id="Page_595"></a>[Pg 595]</span>
+relation between the oxalic acid solution and the permanganate having
+been previously determined the data for calculating the quantity of
+tannin, estimated as gallotannic acid, are at hand.</p>
+
+<p><b>594. The Permanganate Hide Powder Method.</b>—Instead of throwing
+out the tannin with gelatin it may be absorbed by hide powder. The
+principle of the process, save this modification, is the same as in
+the method just described. As described by Trimble, the analysis is
+conducted according to the following directions:<a id="FNanchor_613" href="#Footnote_613" class="fnanchor">[613]</a></p>
+
+<p><i>Reagents Required.</i>—The reagents required for conducting the
+permanganate hide powder process are as follows:</p>
+
+<p>1. <i>Permanganate Solution.</i>—Ten grams of pure potassium
+permanganate are dissolved in six liters of water. The solution is
+standardized with pure tannin. The moisture in the pure tannin is
+determined by drying at 100° to constant weight and then a quantity of
+the undried substance, representing two grams of the dried material, is
+dissolved in one liter of water. Ten cubic centimeters of this solution
+and double that quantity of the indigo solution to be described below,
+are mixed with three-quarters of a liter of water and the permanganate
+solution added from a burette with constant stirring until the liquid
+assumes a greenish color and then, drop by drop, until a pure yellow
+color with a pinkish rim is obtained. Fifty cubic centimeters of the
+pure tannin solution are digested, with frequent shaking, with three
+grams of hide powder which has been previously well moistened and dried
+in a press for eighteen or twenty hours, the contents of the flask
+thrown on a filter and ten cubic centimeters of the filtrate titrated
+with the permanganate solution as directed above. The difference
+between the amount of permanganate solution required for the first and
+second titrations represents the amount of pure tannin or oxidizable
+matter removed by the hide powder.</p>
+
+<p>2. <i>Indigo Solution.</i>—The indicator which is used in the
+titrations is prepared by dissolving thirty grams of sodium
+sulfindigotate in three liters of dilute sulfuric acid made by adding
+one volume of the strong acid to three volumes of water. The solution
+is shaken for a few minutes, thrown upon a filter and the insoluble
+<span class="pagenum"><a id="Page_596"></a>[Pg 596]</span>
+residue washed with sufficient water to make the volume of the filtrate
+six liters.</p>
+
+<p>3. <i>Hide Powder.</i>—The hide powder used should be white, wooly in
+character and sufficiently well extracted with water to afford no other
+extract capable of oxidizing the permanganate solution.</p>
+
+<p><i>The Process.</i>—The reagents having been prepared and tested as
+above, the solution of the substance containing the tannin, prepared
+as described further on, is titrated first with the permanganate
+solution in the manner already given. Fifty cubic centimeters of the
+tannin solution are then shaken, from, time to time for eighteen hours,
+with three grams of hide powder, thrown upon a filter and ten cubic
+centimeters of the filtrate titrated with the potassium permanganate as
+above described. From the data obtained, the quantity of permanganate
+solution corresponding to the tannin removed by the hide powder is
+easily calculated. The value of the permanganate solution having been
+previously set with a pure tannin, renders easy of calculation the
+corresponding amount of pure tannin in the solution under examination.</p>
+
+<p><b>595. Preparation of the Tannin Infusion.</b>—A sample weighing
+about a kilogram should be secured, representing as nearly as possible
+the whole of the materials containing tannin in a given lot. The sample
+is reduced to a fine powder and passed through a sieve containing
+apertures about a millimeter in diameter. The quantity of the sample
+used for the extraction depends largely upon its content of tannin.
+Five grams of nutgalls, ten grams of sumach or twenty grams of oak
+bark represent about the quantities necessary for these classes of
+tannin-holding materials. The sample is boiled for half an hour with
+half a liter of water, filtered through a linen bag into a liter flask
+and washed and pressed with enough water to make the volume of the
+filtrate equal to one liter. The proper quantities of this solution are
+used for the analytical processes described above.</p>
+
+<h3>TOBACCO.</h3>
+
+<p><b>596. Fermented and Unfermented Tobacco.</b>—Samples of tobacco may
+<span class="pagenum"><a id="Page_597"></a>[Pg 597]</span>
+reach the analyst either in the fermented or unfermented state. As a
+basis for comparison, it is advisable in all cases to determine the
+constituents of the sample before fermentation sets in. The analysis,
+after fermentation is complete, will then show the changes of a
+chemical nature which it has undergone during the process of curing and
+sweating. Only tobacco which has undergone fermentation is found to be
+in a suitable condition for consumption. In addition to the natural
+constituents of tobacco, it may contain, in the manufactured state,
+flavoring ingredients such as licorice and sugar, coloring matters and
+in some instances, it is said, opium or other stimulating drugs. It
+is believed, however, that opium is not often found in manufactured
+tobacco, and it has never been found in this laboratory in cigarettes,
+although all the standard brands have been examined for it.<a id="FNanchor_614" href="#Footnote_614" class="fnanchor">[614]</a></p>
+
+<p>In researches made at the Connecticut Station it is shown that
+fermentation produces but little change in the relative quantities
+of nitric acid, ammonia, fiber and starch in the leaves, while those
+of nicotin, albuminoids and amids are diminished. This is not in
+harmony with the generally accepted theory that starch is inverted and
+fermented during the process.<a id="FNanchor_615" href="#Footnote_615" class="fnanchor">[615]</a></p>
+
+<p>The nature of the ferments which are active in producing the changes
+which tobacco undergoes in curing, is not definitely understood. Some
+of the organic constituents of the tobacco undergo a considerable
+change during the process. Any sugar which is found in the freshly
+cured leaves disappears wholly or in part. As products of fermentation
+may also be found succinic, fumaric, formic, acetic, propionic and
+butyric acids.</p>
+
+<p><b>597. Acid and Basic Constituents of Tobacco.</b>—In unfermented
+and fermented tobacco are found certain organic acids, among the most
+important of which are citric, malic, oxalic, pectic and tannic. Of
+the inorganic acids the chief which are found are nitric, sulfuric
+and hydrochloric. Among the bases ammonia and nicotin are the most
+important. Ammonia is found in the unfermented tobacco in only small
+quantities, but in the fermented product it may sometimes reach as high
+as half a per cent. The presence of these two nitrogenous bases in
+<span class="pagenum"><a id="Page_598"></a>[Pg 598]</span>
+tobacco renders the estimation of the proteid matter contained therein
+somewhat tedious and difficult.</p>
+
+<p><b>598. Composition of Tobacco Ash.</b>—The mineral constituents of
+tobacco are highly important from a commercial point of view. The
+burning properties of tobacco depend largely upon the nature of its
+mineral constituents. A sample containing a large quantity of chlorids
+burns much less freely than one in which the sulfates and nitrates
+predominate. For this reason, the use of potash fertilizers containing
+large amounts of chlorin is injudicious in tobacco culture, the
+carbonates and sulfates of potash being preferred. The leaves of the
+tobacco plant contain a much larger percentage of mineral constituents
+than the stems, their respective contents of pure ash, that is ash free
+from carbon dioxid, carbon and sand, being about seventeen and seven.
+The pure ash of the leaves has the following mean composition: Potash
+29.1 per cent, soda 3.2 per cent, lime 36.0 per cent, magnesia 7.4 per
+cent, iron oxid 2.0 per cent, phosphoric acid 4.7 per cent, sulfuric
+acid 6.0 per cent, silica 5.8 per cent, and chlorin 6.7 per cent.<a id="FNanchor_616" href="#Footnote_616" class="fnanchor">[616]</a></p>
+
+<p><b>599. Composition of Tobacco.</b>—The mean composition of some of
+the more important varieties of water-free tobacco is shown in the
+following table:<a id="FNanchor_617" href="#Footnote_617" class="fnanchor">[617]</a></p>
+
+<table class="spb1 spa1">
+   <thead><tr>
+      <th class="tdc">&nbsp;</th>
+      <th class="tdc bb">&nbsp; Havana, &nbsp;<br>per cent.</th>
+      <th class="tdc bb">&nbsp; Sumatra, &nbsp;<br>per cent.</th>
+      <th class="tdc bb">&nbsp; Kentucky, &nbsp;<br>per cent.</th>
+      <th class="tdc bb">Java,<br>&nbsp; per cent. &nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Nicotin</td>
+      <td class="tdr_ws1">3.98</td>
+      <td class="tdr_ws1">2.38</td>
+      <td class="tdr_ws1">4.59</td>
+      <td class="tdr_ws1">3.30</td>
+   </tr><tr>
+      <td class="tdl">Malic acid</td>
+      <td class="tdr_ws1">12.11</td>
+      <td class="tdr_ws1">11.11</td>
+      <td class="tdr_ws1">11.57</td>
+      <td class="tdr_ws1">6.04</td>
+   </tr><tr>
+      <td class="tdl">Citric acid</td>
+      <td class="tdr_ws1">2.05</td>
+      <td class="tdr_ws1">2.53</td>
+      <td class="tdr_ws1">3.40</td>
+      <td class="tdr_ws1">3.30</td>
+   </tr><tr>
+      <td class="tdl">Oxalic acid</td>
+      <td class="tdr_ws1">1.53</td>
+      <td class="tdr_ws1">2.97</td>
+      <td class="tdr_ws1">2.03</td>
+      <td class="tdr_ws1">3.38</td>
+   </tr><tr>
+      <td class="tdl">Acetic acid</td>
+      <td class="tdr_ws1">0.42</td>
+      <td class="tdr_ws1">0.29</td>
+      <td class="tdr_ws1">0.43</td>
+      <td class="tdr_ws1">0.22</td>
+   </tr><tr>
+      <td class="tdl">Tannic acid</td>
+      <td class="tdr_ws1">1.13</td>
+      <td class="tdr_ws1">0.98</td>
+      <td class="tdr_ws1">1.48</td>
+      <td class="tdr_ws1">0.51</td>
+   </tr><tr>
+      <td class="tdl">Nitric acid</td>
+      <td class="tdr_ws1">1.32</td>
+      <td class="tdr_ws1">0.60</td>
+      <td class="tdr_ws1">1.88</td>
+      <td class="tdr_ws1">0.23</td>
+   </tr><tr>
+      <td class="tdl">Pectic acid</td>
+      <td class="tdr_ws1">11.36</td>
+      <td class="tdr_ws1">11.88</td>
+      <td class="tdr_ws1">8.22</td>
+      <td class="tdr_ws1">10.13</td>
+   </tr><tr>
+      <td class="tdl">Cellulose</td>
+      <td class="tdr_ws1">15.76</td>
+      <td class="tdr_ws1">10.59</td>
+      <td class="tdr_ws1">12.48</td>
+      <td class="tdr_ws1">11.82</td>
+   </tr><tr>
+      <td class="tdl">Ammonia</td>
+      <td class="tdr_ws1">0.49</td>
+      <td class="tdr_ws1">0.06</td>
+      <td class="tdr_ws1">0.19</td>
+      <td class="tdr_ws1">0.23</td>
+   </tr><tr>
+      <td class="tdl">Soluble nitrogenous matter</td>
+      <td class="tdr_ws1">7.74</td>
+      <td class="tdr_ws1">8.84</td>
+      <td class="tdr_ws1">13.90</td>
+      <td class="tdr_ws1">10.39</td>
+   </tr><tr>
+      <td class="tdl">Insoluble<span class="ws2">”</span><span class="ws3">”</span></td>
+      <td class="tdr_ws1">9.75</td>
+      <td class="tdr_ws1">7.97</td>
+      <td class="tdr_ws1">8.10</td>
+      <td class="tdr_ws1">9.53</td>
+   </tr><tr>
+      <td class="tdl">Residue and chlorophyll</td>
+      <td class="tdr_ws1">5.15</td>
+      <td class="tdr_ws1">8.63</td>
+      <td class="tdr_ws1">1.99</td>
+      <td class="tdr_ws1">6.45</td>
+   </tr><tr>
+      <td class="tdl">Oil</td>
+      <td class="tdr_ws1">1.03</td>
+      <td class="tdr_ws1">1.26</td>
+      <td class="tdr_ws1">2.28</td>
+      <td class="tdr_ws1">0.81</td>
+   </tr><tr>
+      <td class="tdl">Ash</td>
+      <td class="tdr_ws1">17.50</td>
+      <td class="tdr_ws1">17.03</td>
+      <td class="tdr_ws1">14.36</td>
+      <td class="tdr_ws1">18.46</td>
+   </tr><tr>
+      <td class="tdl">Undetermined</td>
+      <td class="tdr_ws1">8.68</td>
+      <td class="tdr_ws1">12.88</td>
+      <td class="tdr_ws1">13.10</td>
+      <td class="tdr_ws1">15.20</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_599"></a>[Pg 599]</span>
+Among the undetermined matters are included those of a gummy or
+resinous composition not extracted by ether, the exact nature of
+which is not well understood, and the starches, sugars, pentosans and
+galactan.</p>
+
+<p>Tobacco grown in more northern latitudes has less nicotin than the
+samples given in the foregoing table.</p>
+
+<p>The following table shows the composition of tobacco grown in
+Connecticut:<a id="FNanchor_618" href="#Footnote_618" class="fnanchor">[618]</a></p>
+
+<ul class="index fs_105 spa1">
+<li class="isub3"><b>(A)</b> = Unfermented,</li>
+<li class="isub3"><b>(B)</b> = Fermented,</li>
+</ul>
+
+ <table class="spb1 spa1">
+   <thead><tr>
+      <th class="tdc">&nbsp;</th>
+      <th class="tdc fs_105" colspan="2">&nbsp; Upper leaves. &nbsp;</th>
+      <th class="tdc fs_105" colspan="2">&nbsp; Short seconds. &nbsp;</th>
+      <th class="tdc fs_105" colspan="2">&nbsp; First wrappers. &nbsp;</th>
+   </tr><tr>
+      <th class="tdc">&nbsp;</th>
+      <th class="tdc bb fs_105">(A)<br>%</th>
+      <th class="tdc bb fs_105">(B)<br>%</th>
+      <th class="tdc bb fs_105">(A)<br>%</th>
+      <th class="tdc bb fs_105">(B)<br>%</th>
+      <th class="tdc bb fs_105">(A)<br>%</th>
+      <th class="tdc bb fs_105">(B)<br>%</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdl">Water</td>
+      <td class="tdr_wsp">23.50</td>
+      <td class="tdr_wsp">23.40</td>
+      <td class="tdr_wsp">27.40</td>
+      <td class="tdr_wsp">21.10</td>
+      <td class="tdr_wsp">27.50</td>
+      <td class="tdr_wsp">24.90</td>
+   </tr><tr>
+      <td class="tdl">Pure ash</td>
+      <td class="tdr_wsp">14.89</td>
+      <td class="tdr_wsp">15.27</td>
+      <td class="tdr_wsp">22.85</td>
+      <td class="tdr_wsp">25.25</td>
+      <td class="tdr_wsp">15.84</td>
+      <td class="tdr_wsp">16.22</td>
+   </tr><tr>
+      <td class="tdl">Nicotin</td>
+      <td class="tdr_wsp">2.50</td>
+      <td class="tdr_wsp">1.79</td>
+      <td class="tdr_wsp">0.77</td>
+      <td class="tdr_wsp">0.50</td>
+      <td class="tdr_wsp">1.26</td>
+      <td class="tdr_wsp">1.44</td>
+   </tr><tr>
+      <td class="tdl">Nitric acid</td>
+      <td class="tdr_wsp">1.89</td>
+      <td class="tdr_wsp">1.97</td>
+      <td class="tdr_wsp">2.39</td>
+      <td class="tdr_wsp">2.82</td>
+      <td class="tdr_wsp">2.59</td>
+      <td class="tdr_wsp">2.35</td>
+   </tr><tr>
+      <td class="tdl">Ammonia</td>
+      <td class="tdr_wsp">0.67</td>
+      <td class="tdr_wsp">0.71</td>
+      <td class="tdr_wsp">0.16</td>
+      <td class="tdr_wsp">0.16</td>
+      <td class="tdr_wsp">0.33</td>
+      <td class="tdr_wsp">0.47</td>
+   </tr><tr>
+      <td class="tdl">Proteids</td>
+      <td class="tdr_wsp">12.19</td>
+      <td class="tdr_wsp">13.31</td>
+      <td class="tdr_wsp">6.69</td>
+      <td class="tdr_wsp">6.81</td>
+      <td class="tdr_wsp">11.31</td>
+      <td class="tdr_wsp">11.62</td>
+   </tr><tr>
+      <td class="tdl">Fiber</td>
+      <td class="tdr_wsp">7.90</td>
+      <td class="tdr_wsp">8.78</td>
+      <td class="tdr_wsp">7.89</td>
+      <td class="tdr_wsp">8.95</td>
+      <td class="tdr_wsp">9.92</td>
+      <td class="tdr_wsp">10.42</td>
+   </tr><tr>
+      <td class="tdl">Starch</td>
+      <td class="tdr_wsp">3.20</td>
+      <td class="tdr_wsp">3.36</td>
+      <td class="tdr_wsp">2.62</td>
+      <td class="tdr_wsp">3.01</td>
+      <td class="tdr_wsp">2.89</td>
+      <td class="tdr_wsp">3.08</td>
+   </tr><tr>
+      <td class="tdl">Oil and fat</td>
+      <td class="tdr_wsp">3.87</td>
+      <td class="tdr_wsp">3.42</td>
+      <td class="tdr_wsp">2.95</td>
+      <td class="tdr_wsp">3.04</td>
+      <td class="tdr_wsp">2.84</td>
+      <td class="tdr_wsp">2.92</td>
+   </tr><tr>
+      <td class="tdl">Undeterm’d</td>
+      <td class="tdr_wsp">29.39</td>
+      <td class="tdr_wsp">27.99</td>
+      <td class="tdr_wsp">26.28</td>
+      <td class="tdr_wsp">28.36</td>
+      <td class="tdr_wsp">25.52</td>
+      <td class="tdr_wsp">26.88</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><b>600. Estimation of Water.</b>—In the estimation of water in
+vegetable substances, as has already been noted, it is usual to dry
+them in the air or partial vacuum, or in an inert gas, at a temperature
+of 100° until a constant weight is reached. By this process, not only
+the water, but all substances volatile at the temperature and in the
+conditions mentioned are expelled. The quantity of these volatile
+substances in vegetable matter, as a rule, is insignificant and hence
+the total loss may be estimated as water. In the case of tobacco a
+far different condition is presented, inasmuch as the nicotin, which
+sometimes amounts to five per cent of the weight of the sample, is also
+volatile under the conditions mentioned. It is advisable, therefore, to
+dry the sample of tobacco at a temperature not above fifty degrees and
+in a vacuum as complete as possible. Tobacco is also extremely rich in
+its content of crystallized mineral salts, containing often water of
+crystallization, and there is danger of this crystal water being lost
+when the sample is dried at 100°. The desiccation is conveniently made
+in the apparatus described on <a href="#Page_22">page 22</a>. If a high vacuum be employed,
+<span class="pagenum"><a id="Page_600"></a>[Pg 600]</span>
+<i>viz.</i>, about twenty-five inches of mercury, it is better not to
+allow the temperature to go above 40° or 45°. A rather rapid current of
+dry air should be allowed to pass through the apparatus for the more
+speedy removal of the moisture and a dish containing sulfuric acid
+may also be placed inside of the drying apparatus. It is possible by
+proceeding in this way to secure constant weight in the sample after a
+few hours.</p>
+
+<p><b>601. Estimation of Nitric Acid.</b>—The nitric acid in a sample
+of tobacco is most easily estimated by the ferrous chlorid
+process.<a id="FNanchor_619" href="#Footnote_619" class="fnanchor">[619]</a></p>
+
+<p>The sample is best prepared by making an alcoholic extract which is
+accomplished by exhausting about twenty-five grams of the fine tobacco
+powder with 200 cubic centimeters for forty per cent alcohol made
+slightly alkaline by soda lye. The mixture is boiled in a flask with
+a reflux condenser for about an hour. After cooling, the volume is
+completed to a definite quantity, and, after filtering, an aliquot
+part is used for the analytical process. It is evident that the nitric
+acid cannot be estimated in this case after previous reduction to
+ammonia by zinc or iron on account of the presence of ammonia in the
+sample itself. If, however, the amount of ammonia be determined in a
+separate portion of the sample, the nitric acid may be reduced in the
+usual way, by zinc or iron, the total quantity of ammonia determined by
+distillation, the quantity originally present in the sample deducted
+and the residual ammonia calculated to nitric acid.</p>
+
+<p><b>602. Sulfuric and Hydrochloric Acids.</b>—These two acids are
+determined in the ash of the sample by the usual methods. The sulfuric
+acid thus found represents the original sulfuric acid in combination
+with the bases in the mineral parts of the plant, together with that
+produced by the oxidation of the organic sulfur during combustion.
+In order to avoid all loss of sulfur during the combustion, the
+precautions already given should be observed. The separation of the
+sulfur pre-existing as sulfates from that converted into sulfates during
+the combustion is accomplished as previously directed.<a id="FNanchor_620" href="#Footnote_620" class="fnanchor">[620]</a>
+For ordinary purposes, this separation is not necessary.</p>
+
+<p>To avoid loss of chlorin from volatilization during incineration the
+<span class="pagenum"><a id="Page_601"></a>[Pg 601]</span>
+temperature should be kept at the lowest possible point until the mass
+is charred, the soluble salts extracted from the charred mass and the
+incineration completed as usual.</p>
+
+<p><b>603. Oxalic, Citric and Malic Acids.</b>—The separation and
+estimation of organic acids from vegetable tissues is a matter of great
+difficulty, especially when they exist as is usually the case, in very
+minute proportions. During incineration, the salts of the inorganic
+acids are converted into carbonates and the subsequent examination of
+the ash gives no indication of the character of the original acids. In
+the case of tobacco, the organic acids of chief importance, from an
+analytical point of view, are oxalic, citric and malic. These acids may
+be extracted and separated by the following process:<a id="FNanchor_621" href="#Footnote_621" class="fnanchor">[621]</a></p>
+
+<p>Ten grams of the dry tobacco powder are rubbed up in a mortar with
+twelve cubic centimeters of dilute sulfuric acid (one to five) and then
+absorbed with coarse pumice stone powder in sufficient quantity to
+cause all the liquid to disappear. The mass is placed in an extraction
+apparatus of proper size and thoroughly extracted with ether until a
+drop of the extract leaves no acid residue on evaporation. Usually
+about ten hours are required. The organic acids are thus separated
+from the mineral acids. The ether is removed from the extract and the
+residue dissolved in hot water, cooled, filtered, if necessary several
+times, until the solution is separated from the fat and resin which
+have been extracted by the ether. The filtrate is neutralized with
+ammonia, slightly acidified with acetic and the oxalic acid contained
+therein thrown out by means of a dilute solution of calcium acetate,
+which must not be added in excess. The calcium oxalate is separated by
+filtration, and determined as lime oxid. To the filtrate is added drop
+by drop, with constant stirring, a dilute solution of lead acetate,
+prepared by mixing one part of a saturated solution of lead acetate
+with four parts of water. When the precipitate formed has settled, the
+clear supernatant liquid is tested by adding a drop of acetic acid
+and a few drops of the dilute lead acetate. In case a precipitate
+be formed, the addition of the lead acetate is continued until a
+precipitate is secured which will immediately dissolve in acetic acid.
+<span class="pagenum"><a id="Page_602"></a>[Pg 602]</span>
+At this moment the citric acid is almost completely precipitated.
+In order to avoid the accumulation of the acetic acid by reason of
+the repetition of the process as above described, the mixture is
+neutralized each time with dilute ammonia. The precipitated neutral
+lead citrate obtained by the above process, is separated by filtration
+and, in order to avoid its decomposition when washed with pure water,
+it is washed with a very dilute acetic acid solution of lead acetate.
+The washing and filtration are accomplished as quickly as possible,
+and the final washing is made with alcohol of thirty-six per cent
+strength. In the filtrate the residual lead citrate, together with a
+little lead malate, are precipitated by the alcohol used as the wash
+and this precipitate is also separated by filtration. The filtrate
+containing the greater part of the malic acid is evaporated to remove
+the alcohol and treated with lead acetate in excess. Afterwards it
+is mixed with five times its volume of thirty-six per cent alcohol
+containing a half per cent of acetic acid. In these conditions the lead
+malate is completely precipitated as neutral salt, and after standing a
+few hours, is separated by filtration. The three precipitates, obtained
+as above, are dried at 100° and weighed. If the precipitates have
+been collected on filter paper they should be removed as completely
+as possible, the papers incinerated in the usual way and any reduced
+lead converted into nitrate and oxid by treatment with nitric acid and
+subsequent ignition. From the quantities of lead oxid obtained, the
+weights of the citric and malic acids are computed. The precipitate
+which is obtained by the action of alcohol, above noted, is also dried
+and ignited and the lead oxid found divided equally between the citric
+and malic acids, the respective quantities of which found, are included
+in computing their total weights. The weight of the citric acid is
+calculated from the formula <b>(C₆H₅O₇)₂Pb₃ + H₂O</b>, and that of the malic
+acid from the formula <b>C₄H₄O₅Pb + H₂O</b>.</p>
+
+<p><b>604. Acetic Acid.</b>—For the determination of the volatile acids
+of the fatty series existing in tobacco, the following process, also
+due to Schlösing, may be followed:<a id="FNanchor_622" href="#Footnote_622" class="fnanchor">[622]</a></p>
+
+<p>The apparatus employed is shown in <a href="#FIG_121">Fig. 12</a>1. Ten grams of the pulverized
+<span class="pagenum"><a id="Page_603"></a>[Pg 603]</span>
+tobacco, moistened with water and mixed with a little powdered tartaric
+acid, are placed in the tube <i>A</i>. The two ends of the tube,
+<i>A</i>, are stoppered with asbestos or glass wool. Steam, generated
+in the flask, <i>D</i>, is passed into <i>B</i>. After fifteen minutes,
+or as soon as it is certain that the contents of <i>A</i> have reached
+a temperature of 100°, the dish, <i>F</i>, containing mercury, is
+placed in the position shown in the <a href="#FIG_121">figure</a>. The steam,
+by this arrangement, is forced into the lower end of <i>A</i>, passes into the
+condenser <i>E</i>, and the condensed water collected in <i>C</i>. The
+operation should be so conducted as to avoid any condensation of water
+in <i>B</i>. It is advisable during the progress of the distillation,
+which should continue for at least twenty minutes, to neutralize from
+time to time the acetic acid collected in <i>C</i> by a set solution of
+dilute alkali, or, an excess of the alkaline solution may be placed in
+<i>C</i> and the part not neutralized by the acetic acid determined at
+the end of the distillation by titration.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_121" src="images/fig121.jpg" alt="" width="600" height="297" >
+    <p class="center spb1">Fig. 121.—Apparatus for Acetic Acid.</p>
+</div>
+
+<p><b>605. Pectic Acid.</b>—Under this term are included not only the
+pectic acid but all the other bodies of a pectose nature contained in
+tobacco. These bodies are of considerable interest, although they do
+not belong to the most important constituents. In fresh tobacco leaves
+are found three pectin bodies. One pectin is soluble in water, another
+is an insoluble pectose and the third is the pectose body forming
+salts with the alkalies, <i>i. e.</i>, true pectic acid. In fermented
+tobacco pectic acid is found chiefly in combination with lime in the
+ribs of the leaves, serving to give them the necessary stiffness. For
+the estimation of the pectin bodies (mucilage) the powdered tobacco is
+<span class="pagenum"><a id="Page_604"></a>[Pg 604]</span>
+thoroughly extracted with cold water. An aliquot part of the aqueous
+extract is mixed with two volumes of strong alcohol and allowed to
+stand in a well closed vessel in a cool place for twenty-four hours.
+The precipitate is collected on a filter, washed with sixty-six per
+cent alcohol, dried and weighed. The dried residue is incinerated and
+the amount of ash determined. In general, vegetable mucilages contain
+about five per cent of ash. If more than this be found, it is due to
+the solution of the salts of the organic acids contained in the sample.
+A dried vegetable mucilage, obtained as above, dissolves in water to
+a mucilaginous liquid which does not reduce alkaline copper solution
+until it has been hydrolyzed by boiling with a dilute mineral acid.<a id="FNanchor_623" href="#Footnote_623" class="fnanchor">[623]</a></p>
+
+<p><b>606. Tannic Acid.</b>—This acid is separated and estimated by the
+processes given in paragraphs <b><a href="#P_589">589-595</a></b>.</p>
+
+<p><b>607. Starch and Sugar.</b>—The unfermented leaves of tobacco
+contain considerable quantities of carbohydrates in addition to woody
+fiber, pentosans, galactan and cellulose. Among these, starch is the
+most important. Sugar exists in small quantities in the fresh leaf,
+usually not over one per cent. During fermentation, according to some
+authorities, the starch is partially converted into sugar and the
+latter substance disappears under the action of the alcoholic ferments.
+It has been found at the Connecticut Station, however, that the starch
+content of the leaf does not decrease during fermentation. The starch
+and sugar may be determined in the fresh leaves by the methods already
+given.</p>
+
+<p>In the manufacture of certain grades of tobacco it is customary to add
+a quantity of sugar. The analyst may thus be called upon to determine
+in some cases whether the sugar found in a sample is natural or added.
+The occurrence of natural sugars in tobacco has been investigated at
+the instance of the British Treasury.<a id="FNanchor_624" href="#Footnote_624" class="fnanchor">[624]</a></p>
+
+<p>The natural sugars which may be found in sun dried tobaccos usually
+disappear entirely during the process of fermentation. It was found by
+the Somerset House chemists that the content of sugar in commercial
+tobaccos varies from none at all to over fifteen per cent. A remarkable
+example of this variation is reported in two samples from this country,
+<span class="pagenum"><a id="Page_605"></a>[Pg 605]</span>
+one of which, grown in Kentucky, contained no sugar, and the other
+grown in Virginia, 15.2 per cent.</p>
+
+<p>It was noticed that the saccharin matters in the tobaccos examined
+were neutral to polarized light. They are determined by their copper
+reducing power. The tobacco sugars are therefore to be classed with the
+reducing bodies, not optically active, found in the juices of sorghum
+and sugar canes.</p>
+
+<p><b>608. Ammonia.</b>—As has already been intimated, ammonia exists
+only in minute quantities in fresh tobacco leaves, but in considerable
+quantities after fermentation. In the estimation of ammonia, twenty
+grams of the tobacco powder are digested with 250 cubic centimeters of
+water, acidulated with sulfuric and after an hour enough water added
+to make the total quantity 400 cubic centimeters. After filtration, an
+aliquot part of the filtrate, about 200 cubic centimeters, is treated
+with magnesium oxid in excess and the ammonia and nicotin removed by
+distillation in a current of steam. The distillate is collected in
+dilute sulfuric acid of known strength. The total amount of the two
+bases is determined by titration and the quantity of base representing
+the nicotin, which has been determined in a separate sample, subtracted
+in order to obtain the weight of the ammonia.<a id="FNanchor_625" href="#Footnote_625" class="fnanchor">[625]</a></p>
+
+<p>The ammonia in tobacco is determined by Nessler in the following
+manner:<a id="FNanchor_626" href="#Footnote_626" class="fnanchor">[626]</a></p>
+
+<p>The powdered tobacco is mixed with water and magnesium oxid and after
+standing for several hours it is distilled in a current of steam, the
+distillate received in dilute sulfuric acid and the process continued
+until a drop of the distillate gives no reaction for ammonia with the
+nessler reagent. The excess of sulfuric acid in the distillate is
+neutralized with pure sodium carbonate and the nicotin precipitated
+by a neutral solution of mercuric iodid and potassium iodid. The
+precipitate is separated by filtration, the filtrate treated with
+sodium sulfid, and the ammonia again obtained by distillation with
+an alkali, collected in dilute solution of set sulfuric acid and
+determined by titration. The difference of the two determinations
+represents the ammonia.</p>
+
+<p><b>609. Nicotin.</b>—In this laboratory McElroy has made a study of
+<span class="pagenum"><a id="Page_606"></a>[Pg 606]</span>
+some of the best approved methods for determining nicotin, and finds
+the most simple and reliable to be that proposed by Kissling.<a id="FNanchor_627" href="#Footnote_627" class="fnanchor">[627]</a>
+The finely powdered tobacco should be dried at a temperature not
+exceeding 60°, or it may be partially dried at that temperature before
+grinding and the final drying completed afterwards. Twenty grams of
+the powdered sample are intimately mixed by means of a pestle with
+ten cubic centimeters of dilute alcoholic solution of soda lye, made
+by dissolving six grams of sodium hydroxid in forty cubic centimeters
+of water and completing the volume to 100 cubic centimeters with
+ninety-five per cent alcohol. The mass is transferred to an extraction
+paper cylinder, placed in an extraction apparatus and extracted for
+three hours with ether. The ether is nearly all removed by careful
+distillation, the residue mixed with fifty cubic centimeters of a very
+dilute soda lye solution (4 to 100) and subjected to distillation in
+a current of steam. The flask containing the nicotin extract should
+be connected with the condensing apparatus by a safety bulb as is
+usual in the distillation of substances containing fixed alkali. The
+distillation should be conducted rapidly and in such a manner that when
+200 cubic centimeters of the distillate have been collected, not more
+than fifteen cubic centimeters of the liquid remain in the distillation
+flask. In the distillate, the nicotin is determined by titration
+with a set solution of dilute sulfuric acid, using rosolic acid or
+phenacetolin as indicator. It is advisable to titrate each fifty cubic
+centimeters of the distillate as it is received and the distillation is
+continued until the last fifty cubic centimeters give no appreciable
+quantity of the alkaloid. In the calculations one molecule of sulfuric
+acid is equivalent to two molecules of nicotin according to the equation</p>
+
+<ul class="index">
+<li class="isub4"><b>H₂SO₄</b> &nbsp;=&nbsp; <b>(C₁₀H₁₄N₂)₂</b>.</li>
+<li class="isub5">98<span class="ws4">324</span></li>
+</ul>
+
+<p><i>Polarization Method.</i>—Popovici has based a method of detecting
+the quantity of nicotin in tobacco on its property of rotating the
+plane of polarized light.<a id="FNanchor_628" href="#Footnote_628" class="fnanchor">[628]</a>
+The gyrodynat of pure nicotin is expressed by the formula
+[<i>a</i>]<span class="fs_80"><sub>D</sub></span> = -161°.6. When ten
+parts of nicotin are mixed with ninety parts of water, this value
+becomes -74°.1. By reason of this great depression in gyrodynatic value
+<span class="pagenum"><a id="Page_607"></a>[Pg 607]</span>
+Popovici determined the relation which exists between the dilute
+solutions of nicotin and the number of minutes of angular rotation
+produced on polarization in a 200 millimeter tube. In a solution in
+which two grams of nicotin are contained in fifty cubic centimeters,
+each minute of angular rotation is found to correspond to 6.5
+milligrams of nicotin. For one gram in solution in the same volume one
+minute of angular rotation corresponds to 5.9 milligrams and for a half
+gram in solution to 5.7 milligrams.</p>
+
+<p>The nicotin is prepared for polarization by extracting with ether, as
+indicated in the previous paragraph, and the ethereal solution from
+twenty grams of tobacco is shaken with a concentrated solution of
+sodium phosphotungstate in nitric acid by means of which nicotin and
+ammonia are precipitated and rapidly settle. The supernatant liquid
+is carefully poured off and the residue made up to a volume of fifty
+cubic centimeters with distilled water and the nicotin freed from any
+of its compounds by the addition of eight grams of finely powdered
+barium hydroxid. In order to promote the decomposition of the nicotin
+compounds the mixture should be shaken at intervals for several hours.
+The at first blue precipitate changes into blue green and finally into
+yellow. It is separated by filtration and the somewhat yellow colored
+filtrate placed in an observation tube, polarized, the polarization
+calculated to minutes of angular rotation and the number of minutes
+thus found multiplied by the nearest factor given above.</p>
+
+<p>The analyst will find a description of other methods of estimating
+nicotin in tobacco in the periodical literature of analytical
+chemistry.<a id="FNanchor_629" href="#Footnote_629" class="fnanchor">[629]</a></p>
+
+<p><b>610. Estimation of Amid Nitrogen.</b>—For the estimation of amid
+nitrogen ten grams of the powdered tobacco are digested with 100
+cubic centimeters of forty per cent alcohol, the extract separated by
+filtration, acidified with sulfuric and the albumin, peptone, nicotin
+and ammonia precipitated with as little phosphotungstic acid as
+possible. The precipitate is separated by filtration and seventy-five
+cubic centimeters of the filtrate evaporated in a thin glass or tin
+foil capsule after the addition of a little barium chlorid and the
+nitrogen determined in the residue. The nitrogen thus obtained is that
+<span class="pagenum"><a id="Page_608"></a>[Pg 608]</span>
+which was present in an amid state. The nitrogen present as amids,
+ammonia and nicotin subtracted from the total nitrogen leaves that
+present as protein.</p>
+
+<p><b>611. Fractional Extraction of Tobacco.</b>—To determine the
+character of the soluble constituents of tobacco it is advisable
+to subject it to a fractional extraction with different reagents.
+The reagents usually employed in the order mentioned are petroleum
+ether, ether, absolute alcohol, water, dilute soda lye and dilute
+hydrochloric acid. The extract obtained by petroleum ether contains
+vegetable wax, chlorophyll and its alteration products, fat, ethereal
+oils, and resin bodies. The extract with ether may be divided into
+water soluble and alcohol soluble bodies. Among the first are small
+quantities of glucosids and nicotin while in the alcoholic solution
+resin predominates.</p>
+
+<p>The alcoholic extract is also divided into water soluble and alcohol
+soluble parts. The first contains the nicotin, which is insoluble in
+ether, in combination with acids, together with tannic acid and allied
+bodies and also the sugar. The part insoluble in water consists chiefly
+of resin.</p>
+
+<p>The aqueous solution contains the vegetable mucilages (pectin) soluble
+carbohydrates, soluble proteids and organic acids.</p>
+
+<p>The dilute soda lye solution contains chiefly proteids.</p>
+
+<p>The dilute hydrochloric acid solution contains the starch and the
+oxalic acid originally combined with lime. The extractions with dilute
+soda lye and dilute hydrochloric acid should be made at a boiling
+temperature. The residual matter consists of a mixture of carbohydrate
+bodies to which the term crude fiber is usually applied.</p>
+
+<p><b>612. Burning Qualities.</b>—When tobacco is to be used for the
+manufacture of cigars, or cigarettes, or for smoking in pipes, its
+ability to keep burning is a matter of great importance. The tobacco,
+when once ignited, should burn for some time and form, a fluffy ash,
+free of fused mineral particles. A tobacco with good burning properties
+is one containing nitrates in considerable quantity, not too much sugar
+and starch, a porous cellular structure and comparatively free of
+chlorin. In determining comparative burning properties the tests may be
+<span class="pagenum"><a id="Page_609"></a>[Pg 609]</span>
+applied to the single leaf or the tobacco may be first rolled into a
+cigar form and burned in an artificial smoker.</p>
+
+<div class="figleft smcap">
+    <img id="FIG_122" src="images/fig122.jpg" alt="" width="200" height="509" >
+    <p class="center">Fig. 122.<br> Apparatus for Smoking.</p>
+</div>
+
+<p>In applying the test to the leaf it is important that the ignition
+be made with a fuse without flame, which maintains a uniform burning
+power. Any good slow burning fuse may be used and it is applied to the
+leaf in such a way that a hole may be burned in it, leaving its edges
+uniformly ignited. The number of seconds elapsing before the last spark
+is extinguished is noted. At the Connecticut Experiment Station a
+lighter, proposed by Nessler, is employed. It is prepared by digesting
+eighty grams of gum arabic in 120 cubic centimeters, and forty grams of
+gum tragacanth in a quarter of a liter of water for two days, mixing
+the mucilaginous masses and adding ten grams of potassium nitrate and
+about 350 grams of pulverized charcoal. The mixture is rolled, on a
+plate sprinkled with charcoal, into sticks a few inches in length and
+of the diameter of a cigar and dried at a gentle heat. These fuses
+burn slowly and without smoke and are well suited for lighting tobacco
+leaves. Several tests, at least six, should be made with each leaf.
+Leaves having a uniform burning power should be used as comparators and
+the number of seconds they burn be designated by 100. It is important
+that all the samples to be tested be exposed for a day or two to the
+same atmosphere in order that they may have, as nearly as possible,
+the same content of moisture. The burning tests, when possible, should
+be made both before and after fermentation. As a rule fermentation
+improves the burning quality of second rate leaves, but has little
+effect on leaves of the first quality.</p>
+
+<p><b>613. Artificial Smoker.</b>—For the purpose of comparing the
+burning properties of cigars, or of leaves rolled into cigar form, the
+artificial smoking apparatus devised by Penfield and modified in this
+laboratory is employed.<a id="FNanchor_630" href="#Footnote_630" class="fnanchor">[630]</a>
+The construction of the apparatus is shown in the accompanying <a href="#FIG_122">figure.</a></p>
+
+<p>The lighted cigar is set in the tube at the left, so that air entering
+<span class="pagenum"><a id="Page_610"></a>[Pg 610]</span>
+the test-tube must pass through the cigar. The test-tube contains
+enough water to seal the end of the tube carrying the cigar, and is
+connected with the aspirator on the right by the <b>T</b> tube, as
+shown. An arm of the <b>T</b> dips just beneath the surface of the
+liquid in the cup in the center. Water flows in a slow stream into the
+aspirator through the tube at the extreme right, forcing the air out
+through the arm of the <b>T</b> until the siphon begins to act. While
+the water is voided through the long arm of the siphon, air enters
+through the cigar, the liquid rising in the <b>T</b>. The action of
+the apparatus is automatic and intermittent. When the cigar is about
+one-third burned, it is removed without disturbing the ash cone, and
+the latter examined and compared with other samples as a standard. The
+sealing liquid of the long arm of the <b>T</b> may be mercury or water.
+In case mercury be used, care must be taken not to immerse the open end
+of the <b>T</b> more than one millimeter therein.</p>
+
+<h3>FERMENTED BEVERAGES.</h3>
+
+<p><b>614. Description.</b>—Among fermented beverages are included
+those drinks, containing alcohol, prepared by fermenting the sugars
+or starches of fruits, cereals or other agricultural products. Wine
+and beer, in their various forms, and cider are the chief members
+of this class of bodies. Koumiss, although a fermented beverage, is
+not included in this classification, having been noticed under dairy
+products. The large number of artificial drinks, made by mixing alcohol
+with fruit and synthesized essences, is also excluded, although the
+methods of analysis which are used may be applied also to them.</p>
+
+<p>Fermented beverages containing less than two per cent of alcohol are
+<span class="pagenum"><a id="Page_611"></a>[Pg 611]</span>
+usually regarded as non-intoxicating drinks. Beers are of several
+varieties, and the term includes lager beer, ale, porter and stout.
+Distilled liquors are obtained by separating the alcohols and other
+volatile matters from the products of fermentation by distillation.
+It is not practicable here to attempt a description of the methods of
+preparing fermented drinks. Special works on this branch of the subject
+are easy of access.<a id="FNanchor_631" href="#Footnote_631" class="fnanchor">[631]</a></p>
+
+<p><b>615. Important Constituents.</b>—Alcohol is the most important
+constituent of fermented beverages. The solid matters, commonly called
+extract, which are obtained on evaporation are composed of dextrins,
+sugars, organic acids, nitrogenous bodies and mineral matters affording
+ash on combustion. Of these the dextrins and sugars form the chief part
+and the proteid bodies nearly ten per cent in the case of beers made of
+malt and hops. In beers the bitter principles derived from hops, while
+not important by reason of quantity, are of the utmost consequence from
+a gustatory and hygienic point of view. The ash of fermented beverages
+varies with their nature, or with the character of the water used
+in making the mash. In the manufacture of beer, water containing a
+considerable proportion of gypsum is often used, and this substance is
+sometimes added in the course of manufacture, especially of wine. The
+presence of common salt in the ash in any notable quantity is evidence
+of the addition of this condiment, either to improve the taste of the
+beverage or to increase the thirst of the drinker. In cider the organic
+acids, especially malic, are of importance.</p>
+
+<p>Glycerol is a product of fermentation and of the hydrolysis of the fats
+and oils in the substances fermented.</p>
+
+<p><b>616. Specific Gravity.</b>—In order to secure uniformity of
+expression, the specific gravity of fermented beverages is determined
+at about 15°.6, although that is a temperature much below the average
+found in American laboratories. The specific gravity may be determined
+by an alcoholometer, pyknometer or hydrostatic balance in harmony with
+the directions given in paragraphs <b><a href="#P_48">48-54</a></b>
+and <b><a href="#P_285">285</a></b>. By reason of the extractive
+matters held in solution, fermented beverages are usually heavier than
+water, even if the content of alcohol be twenty per cent or more. On
+the other hand distilled liquors are lighter than water.
+<span class="pagenum"><a id="Page_612"></a>[Pg 612]</span></p>
+
+<p><b>617. Determination of Alcohol.</b>—The determination of the
+percentage of alcohol present in a solution is based on two general
+principles. On the one hand, and this is the base of the methods in
+common use, the alcohol is secured mixed only with water and its amount
+determined by ascertaining the specific gravity of the mixture. On the
+other hand the quantity of alcohol in a mixture may be determined by
+ascertaining the temperature of the vapors produced on boiling. This
+is the principle involved in the use of the ebullioscope. The latter
+method is not employed to any extent in this country.</p>
+
+<p><i>Use of the Alcoholometer.</i>—The alcoholometer usually employed
+is known by the name of Gay-Lussac, who first made practical use of it
+in the determination of alcohol. It is constructed in such a way as to
+read directly the volume of absolute alcohol contained in one hundred
+volumes of the liquid at a temperature of 15°.6. The instruments
+employed should be carefully calibrated and thoroughly cleaned by
+washing with absolute alcohol before use. The stem of the instrument
+must be kept free from any greasy substance, and this is secured by
+washing it with ether. After this last washing the analyst should be
+careful not to touch the stem of the instrument with his fingers. It is
+most convenient to make the determination exactly at 15°.6, but when
+made at other temperatures the reading of the instrument is corrected
+by tables which may be found in works especially devoted to the
+analysis of wines.<a id="FNanchor_632" href="#Footnote_632" class="fnanchor">[632]</a></p>
+
+<p>In this country the alcoholometer is used to some extent, but the
+official method is based upon the determination of the specific gravity
+by an instrument constructed in every respect like the alcoholometer,
+but giving the specific gravity of the liquor at 15°.6 instead of its
+percentage by volume in alcohol. The reading of the instrument having
+been determined at a temperature of 15°.6, the corresponding percentage
+of alcohol by volume or by weight is taken directly from the table
+given further on.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_123" src="images/fig123.jpg" alt="" width="400" height="485" >
+    <p class="center spb1">Fig. 123. Metal Distilling Apparatus.</p>
+</div>
+
+<p><i>Methods of Distillation.</i>—The metal apparatus employed in the
+laboratory of the Department of Agriculture, for the distillation of
+fermented beverages in order to determine the percentage of alcohol by
+<span class="pagenum"><a id="Page_613"></a>[Pg 613]</span>
+the method given above, is shown in the accompanying <a href="#FIG_123">figure</a>.
+The apparatus consists of a retort of copper carried on supports in such a
+way as to permit an alcohol or bunsen lamp to be placed under it. It
+is connected with a block tin condenser and the distillate is received
+in a tall graduated cylinder placed under the condenser in such a way
+as to prevent the loss of any alcohol in the form of vapor. Exactly
+300 cubic centimeters of the wine or fermented beverage are used for
+the distillation. Any acid which the wine contains is first saturated
+with calcium carbonate before placing in the retort. Exactly 100
+cubic centimeters of distillate are collected and the volume of the
+distillate is completed to 300 cubic centimeters by the addition of
+recently distilled water.<a id="FNanchor_633" href="#Footnote_633" class="fnanchor">[633]</a>
+The cylinder containing the distillate is brought to a temperature of 15°.6,
+the alcoholometer inserted and its reading taken with the usual precautions.</p>
+
+<p><i>Official Method.</i>—The alcoholometers employed in the official
+methods are calibrated to agree with those used by the officers of the
+Bureau of Internal Revenue. They are most conveniently constructed,
+carrying the thermometer scale in the same stem with that showing
+the specific gravity. It is highly important that the analyst assure
+himself of the exact calibration of the instrument before using it.
+Inasmuch as the volume of the distillate may not be suited in all cases
+to the use of a large alcoholometer, it is customary in this laboratory
+to determine the specific gravity by means of the hydrostatic balance,
+as described further on. Attention is also called to the fact that,
+in the official method, directions are not given to neutralize the
+free acid of the fermented beverage before the distillation. Since the
+Internal Revenue Bureau is concerned chiefly with the determination of
+alcohol in distilled liquors, this omission is of little consequence.
+Even in ordinary fermented beverages the percentage of volatile acids,
+(acetic etc.,) is so small as to make the error due to the failure to
+<span class="pagenum"><a id="Page_614"></a>[Pg 614]</span>
+neutralize it of but little consequence. In order, however, to avoid
+every possibility of error, it is recommended that in all instances the
+free acids of the sample be neutralized before distillation. In this
+laboratory, the distillations are conducted in a glass apparatus shown
+in the accompanying <a href="#FIG_124">figure</a>. The manipulation
+is as follow:<a id="FNanchor_634" href="#Footnote_634" class="fnanchor">[634]</a></p>
+
+<div class="figcenter smcap">
+    <img id="FIG_124" src="images/fig124.jpg" alt="" width="400" height="482" >
+    <p class="center spb1">Fig. 124. Distilling Apparatus.</p>
+</div>
+
+<p>One hundred cubic centimeters of the liquor are placed in a flask of
+from 250 to 300 cubic centimeters capacity, fifty cubic centimeters
+of water added, the flask attached to a vertical condenser by means
+of a bent bulb tube, 100 cubic centimeters distilled and the specific
+gravity of the distillate determined. The distillate is also weighed,
+or its weight calculated from the specific gravity. The corresponding
+percentage of alcohol by weight is obtained from the appended table,
+and this figure multiplied by the weight of the distillate, and the
+<span class="pagenum"><a id="Page_615"></a>[Pg 615]</span>
+result divided by the weight of the sample, gives the per cent of
+alcohol by weight contained therein.</p>
+
+<p>The percentage of alcohol by volume of the liquor is the same as that
+of the distillate, and is obtained directly from the appended table.</p>
+
+<p>In distilled liquors about thirty grams are diluted to 150 cubic
+centimeters, 100 cubic centimeters distilled and the per cent of
+alcohol by weight determined as above.</p>
+
+<p>The percentage of alcohol by volume in the distillate is obtained from
+the appended table. This figure divided by the number expressing the
+volume in cubic centimeters of the liquor taken for the determination
+(calculated from the specific gravity), and the result multiplied by
+100 gives the per cent of alcohol by volume in the original liquor.</p>
+
+<p><b>618. Determining the Specific Gravity of the Distillate.</b>—The
+specific gravity of the distillate may be determined by the pyknometer,
+alcoholometer, hydrostatic balance or in any accurate way. The volume
+of the distillate is not always large enough to be conveniently used
+with an alcoholometer, especially the large ones employed by the Bureau
+of Internal Revenue. In the laboratory of the Agricultural Department,
+it is customary to determine the density of the distillate by the
+hydrostatic balance shown in paragraph <b><a href="#P_285">285</a></b>. The
+specific gravity is in each case determined at 15°.6, referred to water of
+the same temperature, or if at a different temperature calculated thereto.</p>
+
+<p><b>619. Table for Use with Hydrostatic Plummet.</b>—It is more
+convenient to determine the density of the alcoholic distillate at room
+temperature than to reduce it to the standard for which the plummet is
+graduated. In the case of a plummet which displaces exactly five grams,
+or multiple thereof, of distilled water at 15°.6, the corrections for
+temperatures between 12°.2 and 30° are found in the following table,
+prepared by Bigelow.<a id="FNanchor_635" href="#Footnote_635" class="fnanchor">[635]</a></p>
+
+<p>If the weight of the alcoholic solution displaced be 4.96075 grams the
+apparent specific gravity 0.99215 and the temperature of observation
+25°.4, the correction, which is additive, as given in the table is
+0.00191 and the true specific gravity is 0.99406 and the percentage of
+alcohol by volume 4.08.
+<span class="pagenum"><a id="Page_616"></a>[Pg 616]</span></p>
+
+<p>When the plummet does not exactly displace five grams of water at
+15°.6, but nearly so, the table may still be used.</p>
+
+<p>For example, suppose the weight of water displaced be 4.9868 instead of
+five grams. The apparent specific gravity of the water by this plummet
+is 0.99736 and the difference between this and the true specific
+gravity is 0.00264, which is a constant correction to be added to the
+specific gravity as determined in each case.</p>
+
+<p class="f120 spa1"><b><span class="smcap">Correction Table for Specific Gravity.</span></b></p>
+
+<p class="center"><i>Below 15°.6 Subtract;&emsp;Above 15°.6 Add.</i></p>
+
+<table class="spb1 spa1">
+   <thead><tr>
+      <th class="tdc bb">&nbsp; Temp. &nbsp;</th>
+      <th class="tdc bb">&nbsp; Correction.&nbsp;</th>
+      <th class="tdc bb">&nbsp; Temp. &nbsp;</th>
+      <th class="tdc bb">&nbsp; Correction.&nbsp;</th>
+      <th class="tdc bb">&nbsp; Temp. &nbsp;</th>
+      <th class="tdc bb">&nbsp; Correction.&nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc">12.2</td>
+      <td class="tdc">0.00047</td>
+      <td class="tdc">18.2</td>
+      <td class="tdc">0.00043</td>
+      <td class="tdc">24.2</td>
+      <td class="tdc">0.00163</td>
+   </tr><tr>
+      <td class="tdc">12.4</td>
+      <td class="tdc">0.00044</td>
+      <td class="tdc">18.4</td>
+      <td class="tdc">0.00046</td>
+      <td class="tdc">24.4</td>
+      <td class="tdc">0.00167</td>
+   </tr><tr>
+      <td class="tdc">12.6</td>
+      <td class="tdc">0.00042</td>
+      <td class="tdc">18.6</td>
+      <td class="tdc">0.00050</td>
+      <td class="tdc">24.6</td>
+      <td class="tdc">0.00172</td>
+   </tr><tr>
+      <td class="tdc">12.8</td>
+      <td class="tdc">0.00039</td>
+      <td class="tdc">18.8</td>
+      <td class="tdc">0.00053</td>
+      <td class="tdc">24.8</td>
+      <td class="tdc">0.00176</td>
+   </tr><tr>
+      <td class="tdc">13.0</td>
+      <td class="tdc">0.00037</td>
+      <td class="tdc">19.0</td>
+      <td class="tdc">0.00057</td>
+      <td class="tdc">25.0</td>
+      <td class="tdc">0.00181</td>
+   </tr><tr>
+      <td class="tdc">13.2</td>
+      <td class="tdc">0.00634</td>
+      <td class="tdc">19.2</td>
+      <td class="tdc">0.00061</td>
+      <td class="tdc">25.2</td>
+      <td class="tdc">0.00186</td>
+   </tr><tr>
+      <td class="tdc">13.4</td>
+      <td class="tdc">0.00032</td>
+      <td class="tdc">19.4</td>
+      <td class="tdc">0.00065</td>
+      <td class="tdc">25.4</td>
+      <td class="tdc">0.00191</td>
+   </tr><tr>
+      <td class="tdc">13.6</td>
+      <td class="tdc">0.00029</td>
+      <td class="tdc">19.6</td>
+      <td class="tdc">0.00068</td>
+      <td class="tdc">25.6</td>
+      <td class="tdc">0.00195</td>
+   </tr><tr>
+      <td class="tdc">13.8</td>
+      <td class="tdc">0.00027</td>
+      <td class="tdc">19.8</td>
+      <td class="tdc">0.00072</td>
+      <td class="tdc">25.8</td>
+      <td class="tdc">0.00200</td>
+   </tr><tr>
+      <td class="tdc">14.0</td>
+      <td class="tdc">0.00024</td>
+      <td class="tdc">20.0</td>
+      <td class="tdc">0.00076</td>
+      <td class="tdc">26.0</td>
+      <td class="tdc">0.00205</td>
+   </tr><tr>
+      <td class="tdc">14.2</td>
+      <td class="tdc">0.00021</td>
+      <td class="tdc">20.2</td>
+      <td class="tdc">0.00080</td>
+      <td class="tdc">26.2</td>
+      <td class="tdc">0.00210</td>
+   </tr><tr>
+      <td class="tdc">14.4</td>
+      <td class="tdc">0.00018</td>
+      <td class="tdc">20.4</td>
+      <td class="tdc">0.00084</td>
+      <td class="tdc">26.4</td>
+      <td class="tdc">0.00215</td>
+   </tr><tr>
+      <td class="tdc">14.6</td>
+      <td class="tdc">0.00015</td>
+      <td class="tdc">20.6</td>
+      <td class="tdc">0.00087</td>
+      <td class="tdc">26.6</td>
+      <td class="tdc">0.00220</td>
+   </tr><tr>
+      <td class="tdc">14.8</td>
+      <td class="tdc">0.00012</td>
+      <td class="tdc">20.8</td>
+      <td class="tdc">0.00091</td>
+      <td class="tdc">26.8</td>
+      <td class="tdc">0.00225</td>
+   </tr><tr>
+      <td class="tdc">15.0</td>
+      <td class="tdc">0.00009</td>
+      <td class="tdc">21.0</td>
+      <td class="tdc">0.00095</td>
+      <td class="tdc">27.0</td>
+      <td class="tdc">0.00230</td>
+   </tr><tr>
+      <td class="tdc">15.2</td>
+      <td class="tdc">0.00006</td>
+      <td class="tdc">21.2</td>
+      <td class="tdc">0.00099</td>
+      <td class="tdc">27.2</td>
+      <td class="tdc">0.00235</td>
+   </tr><tr>
+      <td class="tdc bb">15.4</td>
+      <td class="tdc bb">0.00003</td>
+      <td class="tdc">21.4</td>
+      <td class="tdc">0.00103</td>
+      <td class="tdc"> 27.4</td>
+      <td class="tdc">0.00240</td>
+   </tr><tr>
+      <td class="tdc bb"><b>15.6</b></td>
+      <td class="tdc bb"><b>0.00000</b></td>
+      <td class="tdc">21.6</td>
+      <td class="tdc">0.00107</td>
+      <td class="tdc">27.6</td>
+      <td class="tdc">0.00246</td>
+   </tr><tr>
+      <td class="tdc">15.8</td>
+      <td class="tdc">0.00003</td>
+      <td class="tdc">21.8</td>
+      <td class="tdc">0.00111</td>
+      <td class="tdc">27.8</td>
+      <td class="tdc">0.00251</td>
+   </tr><tr>
+      <td class="tdc">16.0</td>
+      <td class="tdc">0.00006</td>
+      <td class="tdc">22.0</td>
+      <td class="tdc">0.00115</td>
+      <td class="tdc">28.0</td>
+      <td class="tdc">0.00256</td>
+   </tr><tr>
+      <td class="tdc">16.2</td>
+      <td class="tdc">0.00009</td>
+      <td class="tdc">22.2</td>
+      <td class="tdc">0.00119</td>
+      <td class="tdc">28.2</td>
+      <td class="tdc">0.00261</td>
+   </tr><tr>
+      <td class="tdc">16.4</td>
+      <td class="tdc">0.00012</td>
+      <td class="tdc">22.4</td>
+      <td class="tdc">0.00123</td>
+      <td class="tdc">28.4</td>
+      <td class="tdc">0.00267</td>
+   </tr><tr>
+      <td class="tdc">16.6</td>
+      <td class="tdc">0.00016</td>
+      <td class="tdc">22.6</td>
+      <td class="tdc">0.00128</td>
+      <td class="tdc">28.6</td>
+      <td class="tdc">0.00272</td>
+   </tr><tr>
+      <td class="tdc">16.8</td>
+      <td class="tdc">0.00019</td>
+      <td class="tdc">22.8</td>
+      <td class="tdc">0.00132</td>
+      <td class="tdc">28.8</td>
+      <td class="tdc">0.00278</td>
+   </tr><tr>
+      <td class="tdc">17.0</td>
+      <td class="tdc">0.00022</td>
+      <td class="tdc">23.0</td>
+      <td class="tdc">0.00136</td>
+      <td class="tdc">29.0</td>
+      <td class="tdc">0.00283</td>
+   </tr><tr>
+      <td class="tdc">17.2</td>
+      <td class="tdc">0.00025</td>
+      <td class="tdc">23.2</td>
+      <td class="tdc">0.00140</td>
+      <td class="tdc">29.2</td>
+      <td class="tdc">0.00288</td>
+   </tr><tr>
+      <td class="tdc">17.4</td>
+      <td class="tdc">0.00029</td>
+      <td class="tdc">23.4</td>
+      <td class="tdc">0.00145</td>
+      <td class="tdc">29.4</td>
+      <td class="tdc">0.00294</td>
+   </tr><tr>
+      <td class="tdc">17.6</td>
+      <td class="tdc">0.00032</td>
+      <td class="tdc">23.6</td>
+      <td class="tdc">0.00149</td>
+      <td class="tdc">29.6</td>
+      <td class="tdc">0.00299</td>
+   </tr><tr>
+      <td class="tdc">17.8</td>
+      <td class="tdc">0.00036</td>
+      <td class="tdc">23.8</td>
+      <td class="tdc">0.00154</td>
+      <td class="tdc">29.8</td>
+      <td class="tdc">0.00306</td>
+   </tr><tr>
+      <td class="tdc">18.0</td>
+      <td class="tdc">0.00039</td>
+      <td class="tdc">24.0</td>
+      <td class="tdc">0.00158</td>
+      <td class="tdc">30.0</td>
+      <td class="tdc">0.00311</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>The table is only accurate when the distillate does not contain over
+seven nor less than three per cent of alcohol. If the distillate
+contain more than seven per cent of alcohol it is diluted and the
+compensating correction made.</p>
+
+<p><b>620. Calculating Results.</b>—The specific gravity of the alcoholic
+distillate having been determined by any approved method and corrected
+to a temperature of 15°.6, the corresponding per cents of alcohol by
+volume and by weight are found by consulting the following table.<a id="FNanchor_636" href="#Footnote_636" class="fnanchor">[636]</a>
+If, for example, the corrected specific gravity be exactly that given
+in any figure of the table the corresponding per cents are directly
+read. If the specific gravity found fall between two numbers in the
+table the corresponding per cents are determined by interpolation.
+<span class="pagenum"><a id="Page_617"></a>[Pg 617]</span></p>
+
+<p class="f120"><b><span class="smcap">Table Showing Percentage of Alcohol<br>
+            by Weight and by Volume.</span></b></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb bt bl">Specific<br>gravity at<br>&nbsp; 15°.6./15°.6. &nbsp;</th>
+      <th class="tdc bb bt bl">Per cent<br>alcohol<br>&nbsp; by volume. &nbsp;</th>
+      <th class="tdc bb bt bl br">Per cent<br>alcohol<br>&nbsp; by weight. &nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdr_ws1 bl">1.00000</td>
+      <td class="tdr_ws1 bl">0.00</td>
+      <td class="tdr_ws1 bl br">0.00</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">0.99992</td>
+      <td class="tdr_ws1 bl">.05</td>
+      <td class="tdr_ws1 bl br">.04</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">984</td>
+      <td class="tdr_ws1 bl">.10</td>
+      <td class="tdr_ws1 bl br">.08</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">976</td>
+      <td class="tdr_ws1 bl">.15</td>
+      <td class="tdr_ws1 bl br">.12</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">968</td>
+      <td class="tdr_ws1 bl">.20</td>
+      <td class="tdr_ws1 bl br">.16</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">961</td>
+      <td class="tdr_ws1 bl">.25</td>
+      <td class="tdr_ws1 bl br">.20</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">953</td>
+      <td class="tdr_ws1 bl">.30</td>
+      <td class="tdr_ws1 bl br">.24</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">945</td>
+      <td class="tdr_ws1 bl">.35</td>
+      <td class="tdr_ws1 bl br">.28</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">937</td>
+      <td class="tdr_ws1 bl">.40</td>
+      <td class="tdr_ws1 bl br">.32</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl bb">930</td>
+      <td class="tdr_ws1 bl bb">.45</td>
+      <td class="tdr_ws1 bl br bb">.36</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">.99923</td>
+      <td class="tdr_ws1 bl">0.50</td>
+      <td class="tdr_ws1 bl br">0.40</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">915</td>
+      <td class="tdr_ws1 bl">.55</td>
+      <td class="tdr_ws1 bl br">.44</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">907</td>
+      <td class="tdr_ws1 bl">.60</td>
+      <td class="tdr_ws1 bl br">.48</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">900</td>
+      <td class="tdr_ws1 bl">.65</td>
+      <td class="tdr_ws1 bl br">.52</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">892</td>
+      <td class="tdr_ws1 bl">.70</td>
+      <td class="tdr_ws1 bl br">.56</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">884</td>
+      <td class="tdr_ws1 bl">.75</td>
+      <td class="tdr_ws1 bl br">.60</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">877</td>
+      <td class="tdr_ws1 bl">.80</td>
+      <td class="tdr_ws1 bl br">.64</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">869</td>
+      <td class="tdr_ws1 bl">.85</td>
+      <td class="tdr_ws1 bl br">.67</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">861</td>
+      <td class="tdr_ws1 bl">.90</td>
+      <td class="tdr_ws1 bl br">.71</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl bb">854</td>
+      <td class="tdr_ws1 bl bb">.95</td>
+      <td class="tdr_ws1 bl br bb">.75</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">.99849</td>
+      <td class="tdr_ws1 bl">1.00</td>
+      <td class="tdr_ws1 bl br">0.79</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">842</td>
+      <td class="tdr_ws1 bl">.05</td>
+      <td class="tdr_ws1 bl br">.83</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">834</td>
+      <td class="tdr_ws1 bl">.10</td>
+      <td class="tdr_ws1 bl br">.87</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">827</td>
+      <td class="tdr_ws1 bl">.15</td>
+      <td class="tdr_ws1 bl br">.91</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">819</td>
+      <td class="tdr_ws1 bl">.20</td>
+      <td class="tdr_ws1 bl br">.95</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">812</td>
+      <td class="tdr_ws1 bl">.25</td>
+      <td class="tdr_ws1 bl br">.99</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">805</td>
+      <td class="tdr_ws1 bl">.30</td>
+      <td class="tdr_ws1 bl br">1.03</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">797</td>
+      <td class="tdr_ws1 bl">.35</td>
+      <td class="tdr_ws1 bl br">.07</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">790</td>
+      <td class="tdr_ws1 bl">.40</td>
+      <td class="tdr_ws1 bl br">.11</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl bb">782</td>
+      <td class="tdr_ws1 bl bb">.45</td>
+      <td class="tdr_ws1 bl br bb">.15</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">.99775</td>
+      <td class="tdr_ws1 bl">1.50</td>
+      <td class="tdr_ws1 bl br">1.19</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">768</td>
+      <td class="tdr_ws1 bl">.55</td>
+      <td class="tdr_ws1 bl br">.23</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">760</td>
+      <td class="tdr_ws1 bl">.60</td>
+      <td class="tdr_ws1 bl br">.27</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">753</td>
+      <td class="tdr_ws1 bl">.65</td>
+      <td class="tdr_ws1 bl br">.31</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">745</td>
+      <td class="tdr_ws1 bl">.70</td>
+      <td class="tdr_ws1 bl br">.35</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">738</td>
+      <td class="tdr_ws1 bl">.75</td>
+      <td class="tdr_ws1 bl br">.39</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">731</td>
+      <td class="tdr_ws1 bl">.80</td>
+      <td class="tdr_ws1 bl br">.43</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">723</td>
+      <td class="tdr_ws1 bl">.85</td>
+      <td class="tdr_ws1 bl br">.47</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">716</td>
+      <td class="tdr_ws1 bl">.90</td>
+      <td class="tdr_ws1 bl br">.51</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl bb">708</td>
+      <td class="tdr_ws1 bl bb">.95</td>
+      <td class="tdr_ws1 bl br bb">.55</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">.99701</td>
+      <td class="tdr_ws1 bl">2.00</td>
+      <td class="tdr_ws1 bl br">1.59</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">694</td>
+      <td class="tdr_ws1 bl">.05</td>
+      <td class="tdr_ws1 bl br">.63</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">687</td>
+      <td class="tdr_ws1 bl">.10</td>
+      <td class="tdr_ws1 bl br">.67</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">679</td>
+      <td class="tdr_ws1 bl">.15</td>
+      <td class="tdr_ws1 bl br">.71</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">672</td>
+      <td class="tdr_ws1 bl">.20</td>
+      <td class="tdr_ws1 bl br">.75</td>
+   </tr><tr>
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+                 <span class="pagenum"><a id="Page_618"></a>[Pg 618]</span></td>
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+               <span class="pagenum"><a id="Page_619"></a>[Pg 619]</span></td>
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+                   <span class="pagenum"><a id="Page_620"></a>[Pg 620]</span></td>
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+      <td class="tdr_ws1 bl br">.34</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">664</td>
+      <td class="tdr_ws1 bl">.85</td>
+      <td class="tdr_ws1 bl br">.38</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">655</td>
+      <td class="tdr_ws1 bl">.90</td>
+      <td class="tdr_ws1 bl br">.43</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl bb">645</td>
+      <td class="tdr_ws1 bl bb">.95</td>
+      <td class="tdr_ws1 bl br bb">.47</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">.93636</td>
+      <td class="tdr_ws1 bl">49.00</td>
+      <td class="tdr_ws1 bl br">41.52</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">626</td>
+      <td class="tdr_ws1 bl">.05</td>
+      <td class="tdr_ws1 bl br">.57</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">617</td>
+      <td class="tdr_ws1 bl">.10</td>
+      <td class="tdr_ws1 bl br">.61</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">607</td>
+      <td class="tdr_ws1 bl">.15</td>
+      <td class="tdr_ws1 bl br">.66</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">598</td>
+      <td class="tdr_ws1 bl">.20</td>
+      <td class="tdr_ws1 bl br">.71</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">588</td>
+      <td class="tdr_ws1 bl">.25</td>
+      <td class="tdr_ws1 bl br">.76</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">578</td>
+      <td class="tdr_ws1 bl">.30</td>
+      <td class="tdr_ws1 bl br">.80</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">569</td>
+      <td class="tdr_ws1 bl">.35</td>
+      <td class="tdr_ws1 bl br">.85</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">559</td>
+      <td class="tdr_ws1 bl">.40</td>
+      <td class="tdr_ws1 bl br">.90</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl bb">550</td>
+      <td class="tdr_ws1 bl bb">.45</td>
+      <td class="tdr_ws1 bl br bb">.94</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">.93540</td>
+      <td class="tdr_ws1 bl">49.50</td>
+      <td class="tdr_ws1 bl br">41.99</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">530</td>
+      <td class="tdr_ws1 bl">.55</td>
+      <td class="tdr_ws1 bl br">42.04</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">521</td>
+      <td class="tdr_ws1 bl">.60</td>
+      <td class="tdr_ws1 bl br">.08</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">511</td>
+      <td class="tdr_ws1 bl">.65</td>
+      <td class="tdr_ws1 bl br">.13</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">502</td>
+      <td class="tdr_ws1 bl">.70</td>
+      <td class="tdr_ws1 bl br">.18</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">492</td>
+      <td class="tdr_ws1 bl">.75</td>
+      <td class="tdr_ws1 bl br">.23</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">482</td>
+      <td class="tdr_ws1 bl">.80</td>
+      <td class="tdr_ws1 bl br">.27</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">473</td>
+      <td class="tdr_ws1 bl">.85</td>
+      <td class="tdr_ws1 bl br">.32</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl">463</td>
+      <td class="tdr_ws1 bl">.90</td>
+      <td class="tdr_ws1 bl br">.37</td>
+   </tr><tr>
+      <td class="tdr_ws1 bl bb">454</td>
+      <td class="tdr_ws1 bl bb">.95</td>
+      <td class="tdr_ws1 bl br bb">.41</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_622"></a>[Pg 622]</span>
+<b>621. Determination of Percentage of Alcohol by Means Of Vapor
+Temperature.</b>—The temperature of a mixture of alcohol and water
+vapors is less than that of water alone and the depression is inversely
+proportional to the quantity of alcohol present. This principle is
+utilized in the construction of the ebullioscope or ebulliometer.
+In this apparatus the temperature of pure boiling water vapor is
+determined by a preliminary experiment. This point must be frequently
+revised in order to correct it for variations in barometric pressure.
+The water is withdrawn from the boiler of the apparatus, the same
+volume of a wine or beer placed therein, and the vapor temperature
+again determined. By comparing the boiling point of the wine, with a
+scale calibrated for different percentages of alcohol, the quantity
+of spirit present is determined. When water vapor is at 100° a <i>vin
+ordinaire</i> having eight per cent of alcohol gives a vapor at 93°.8.
+The presence of extractive matters in the sample, which tend to raise
+its boiling point, is neglected in the calculation of results.</p>
+
+<p><b>622. Improved Ebullioscope.</b>—The principle mentioned in the
+above paragraph may be applied with a considerable degree of accuracy,
+by using the improved ebullioscope described below.<a id="FNanchor_637" href="#Footnote_637" class="fnanchor">[637]</a></p>
+
+<p>The apparatus consists of a glass flask F, shaped somewhat like an
+erlenmeyer, closed at the top with a rubber stopper carrying a central
+aperture for the insertion of the delicate thermometer A B, and a
+lateral smaller aperture for connecting the interior of the flask with
+the condenser D. The return of the condensed vapors from D is effected
+through the tube entering the flask F in such a manner as to deliver
+the condensed liquid beneath the surface of the liquid in F as shown
+in the <a href="#FIG_125">figure</a>. The flask F contains pieces of scrap
+platinum or pumice stone to prevent bumping and secure an even ebullition.
+The flask F rests upon a disk of asbestos, perforated in such a way as to
+have the opening fully covered by the bottom of the flask. To protect F against
+the influence of air currents it is enclosed in the glass cylinder E
+resting on the asbestos disk below and closed with a detachable soft
+rubber cover at the top. The temperature between the cylinder E and the
+<span class="pagenum"><a id="Page_623"></a>[Pg 623]</span>
+flask F is measured by the thermometer C and the flame of the lamp
+G should be so adjusted as to bring the temperature between the
+flask F and the cylinder E to about 90° at the time of reading the
+thermometer B. The bulb of the thermometer B may be protected by a
+thin glass tube carrying distilled water, so adjusted as to prevent
+the escape of the watery vapor into F. The thermometer B is such as
+is used for determining molecular weights by the cryoscopic method.
+It has a cistern at A which holds any excess of mercury not needed in
+<i>adjusting the thermometer</i> for any required temperature.</p>
+
+<div class="figcenter smcap">
+    <img id="FIG_125" src="images/fig125.jpg" alt="" width="300" height="605" >
+    <p class="center spb1">Fig. 125. Improved Ebullioscope.</p>
+</div>
+
+<p>A second apparatus, exactly similar to the one described, is
+conveniently used for measuring the changes in <i>barometric</i>
+pressure during the process of the analysis. The temperature of the
+vapor of boiling water having been first determined, the beer or wine
+is placed in F, and the temperature of the vapor of the boiling liquid
+determined after the temperature of the air layer between E and F
+reaches about 90°, measured on the thermometer C. By using alcoholic
+mixtures of known strength the depression for each changing per cent of
+alcohol is determined for each system of apparatus employed, and this
+having once been done, the percentage of alcohol in any unknown liquid
+is at once determined by inspecting the thermometer, the bulb of which
+<span class="pagenum"><a id="Page_624"></a>[Pg 624]</span>
+is immersed in the vapor from the boiling liquid. In the apparatus
+<a href="#FIG_125">figured</a>, a depression of 0°.8 is equivalent to
+one per cent of alcohol by volume. Full directions for the manipulation
+of the apparatus may be found in the paper cited above.</p>
+
+<p><b>623. Total Fixed Matters.</b>—The residue left on evaporating a
+fermented beverage to dryness is commonly known as extractive matter,
+or simply extract. It is composed chiefly of unfermented carbohydrates,
+organic acids, nitrogenous bodies, glycerol and mineral substances.
+Hydrochloric and sulfuric acids may also be found therein. If any
+non-volatile preservatives have been used in the sample, such as
+borax, salicylates and the like, these will also be found in the
+solid residue. The bodies which escape are water, alcohols, ethers
+and essential oils. The character of the residue left by wines and
+beers is evidently different. In each case it should contain typical
+components which aid in judging of the purity of the sample. For
+instance, in beers the substitution for malt of carbohydrate bodies
+comparatively free of proteids, produces a beer containing a deficiency
+of nitrogenous bodies. Pure malt beer will rarely have less than
+one-half of a per cent of proteids, while beer made largely of glucose,
+rice or hominy grits, will have a much smaller quantity. First will be
+described below the methods of determining the fixed residue left on
+evaporation, and thereafter the processes for ascertaining its leading
+components.</p>
+
+<p><b>624. Methods of the Official Chemists.</b>—Two methods are in use
+by the official chemists for determining the fixed solids in fermented
+beverages.<a id="FNanchor_638" href="#Footnote_638" class="fnanchor">[638]</a>
+They are as follows:</p>
+
+<p><i>Direct Method.</i>—Fifty cubic centimeters of the sample are
+weighed, placed in a platinum dish about eighty millimeters in diameter
+and capable of holding about seventy-five cubic centimeters and
+evaporated on the steam bath to a sirupy consistence. The residue is
+heated for two and a half hours in a drying oven at the temperature of
+boiling water and weighed.</p>
+
+<p><i>In Sweet Wines.</i>—Ten cubic centimeters of the liquor are weighed
+and diluted to 100 with water. Fifty cubic centimeters of this solution
+are evaporated as described above.</p>
+
+<p><i>Optional Method.</i>—Fifty cubic centimeters of the sample are
+placed in a platinum or porcelain dish and evaporated on the steam bath
+<span class="pagenum"><a id="Page_625"></a>[Pg 625]</span>
+until the volume is reduced to one-third. The dealcoholized liquid
+is washed into a fifty cubic centimeter flask, cooled and made up to
+the original volume. It is mixed thoroughly and the specific gravity
+ascertained with a pyknometer, hydrostatic balance or an accurately
+standardized hydrometer. The percentage of total solids is obtained
+from the appended table. The column on the left of the specific gravity
+gives the percentage of extract in a wine, as calculated by Hager,
+and that on the right the percentage of extract in a beer or wort,
+as calculated by Schultze. According to Baumert, however, Schultze’s
+table gives results which approximate more closely the data obtained by
+direct estimation than does Hager’s.</p>
+
+<p class="f120 spa1"><b><span class="smcap">Tables of Hager and Schultze for<br>
+the Determination of Extract<br>by the Indirect Method.</span></b></p>
+
+<table class="spb1">
+   <thead><tr>
+      <th class="tdc bb bl bt2">&nbsp; Hager. &nbsp;</th>
+      <th class="tdc bb bl bt2">&nbsp; Specific gravity. &nbsp;</th>
+      <th class="tdc bb bl br bt2">&nbsp; Schultze. &nbsp;</th>
+   </tr></thead>
+   <tbody><tr>
+      <td class="tdc bl">0.84</td>
+      <td class="tdc bl">1.0038</td>
+      <td class="tdc bl br">1.00</td>
+   </tr><tr>
+      <td class="tdc bl">0.86</td>
+      <td class="tdc bl">1.0039</td>
+      <td class="tdc bl br">1.02</td>
+   </tr><tr>
+      <td class="tdc bl">0.88</td>
+      <td class="tdc bl">1.0040</td>
+      <td class="tdc bl br">1.05</td>
+   </tr><tr>
+      <td class="tdc bl">0.90</td>
+      <td class="tdc bl">1.0041</td>
+      <td class="tdc bl br">1.08</td>
+   </tr><tr>
+      <td class="tdc bl">0.92</td>
+      <td class="tdc bl">1.0042</td>
+      <td class="tdc bl br">1.10</td>
+   </tr><tr>
+      <td class="tdc bl">0.94</td>
+      <td class="tdc bl">1.0043</td>
+      <td class="tdc bl br">1.13</td>
+   </tr><tr>
+      <td class="tdc bl">0.96</td>
+      <td class="tdc bl">1.0044</td>
+      <td class="tdc bl br">1.15</td>
+   </tr><tr>
+      <td class="tdc bl">0.98</td>
+      <td class="tdc bl">1.0045</td>
+      <td class="tdc bl br">1.18</td>
+   </tr><tr>
+      <td class="tdc bl">1.00</td>
+      <td class="tdc bl">1.0046</td>
+      <td class="tdc bl br">1.21</td>
+   </tr><tr>
+      <td class="tdc bl">1.02</td>
+      <td class="tdc bl">1.0047</td>
+      <td class="tdc bl br">1.23</td>
+   </tr><tr>
+      <td class="tdc bl">1.04</td>
+      <td class="tdc bl">1.0048</td>
+      <td class="tdc bl br">1.26</td>
+   </tr><tr>
+      <td class="tdc bl bb">1.06</td>
+      <td class="tdc bl bb">1.0049</td>
+      <td class="tdc bl br bb">1.29</td>
+   </tr><tr>
+      <td class="tdc bl">1.08</td>
+      <td class="tdc bl">1.0050</td>
+      <td class="tdc bl br">1.31</td>
+   </tr><tr>
+      <td class="tdc bl">1.10</td>
+      <td class="tdc bl">1.0051</td>
+      <td class="tdc bl br">1.34</td>
+   </tr><tr>
+      <td class="tdc bl">1.12</td>
+      <td class="tdc bl">1.0052</td>
+      <td class="tdc bl br">1.36</td>
+   </tr><tr>
+      <td class="tdc bl">1.15</td>
+      <td class="tdc bl">1.0053</td>
+      <td class="tdc bl br">1.39</td>
+   </tr><tr>
+      <td class="tdc bl">1.17</td>
+      <td class="tdc bl">1.0054</td>
+      <td class="tdc bl br">1.41</td>
+   </tr><tr>
+      <td class="tdc bl">1.19</td>
+      <td class="tdc bl">1.0055</td>
+      <td class="tdc bl br">1.44</td>
+   </tr><tr>
+      <td class="tdc bl">1.22</td>
+      <td class="tdc bl">1.0056</td>
+      <td class="tdc bl br">1.46</td>
+   </tr><tr>
+      <td class="tdc bl">1.25</td>
+      <td class="tdc bl">1.0057</td>
+      <td class="tdc bl br">1.49</td>
+   </tr><tr>
+      <td class="tdc bl">1.27</td>
+      <td class="tdc bl">1.0058</td>
+      <td class="tdc bl br">1.51</td>
+   </tr><tr>
+      <td class="tdc bl bb">1.30</td>
+      <td class="tdc bl bb">1.0059</td>
+      <td class="tdc bl br bb">1.54</td>
+   </tr><tr>
+      <td class="tdc bl">1.32</td>
+      <td class="tdc bl">1.0060</td>
+      <td class="tdc bl br">1.56</td>
+   </tr><tr>
+      <td class="tdc bl">1.34</td>
+      <td class="tdc bl">1.0061</td>
+      <td class="tdc bl br">1.59</td>
+   </tr><tr>
+      <td class="tdc bl">1.37</td>
+      <td class="tdc bl">1.0062</td>
+      <td class="tdc bl br">1.62</td>
+   </tr><tr>
+      <td class="tdc bl">1.39</td>
+      <td class="tdc bl">1.0063</td>
+      <td class="tdc bl br">1.64</td>
+   </tr><tr>
+      <td class="tdc bl">1.42</td>
+      <td class="tdc bl">1.0064</td>
+      <td class="tdc bl br">1.67</td>
+   </tr><tr>
+      <td class="tdc bl">1.44</td>
+      <td class="tdc bl">1.0065</td>
+      <td class="tdc bl br">1.69</td>
+   </tr><tr>
+      <td class="tdc bl">1.46</td>
+      <td class="tdc bl">1.0066</td>
+      <td class="tdc bl br">1.72</td>
+   </tr><tr>
+      <td class="tdc bl">1.48</td>
+      <td class="tdc bl">1.0067</td>
+      <td class="tdc bl br">1.74</td>
+   </tr><tr>
+      <td class="tdc bl">1.50</td>
+      <td class="tdc bl">1.0068</td>
+      <td class="tdc bl br">1.77</td>
+   </tr><tr>
+      <td class="tdc bl bb">1.52</td>
+      <td class="tdc bl bb">1.0069</td>
+      <td class="tdc bl br bb">1.79</td>
+   </tr><tr>
+      <td class="tdc bl">1.55</td>
+      <td class="tdc bl">1.0070</td>
+      <td class="tdc bl br">1.82</td>
+   </tr><tr>
+      <td class="tdc bl">1.57</td>
+      <td class="tdc bl">1.0071</td>
+      <td class="tdc bl br">1.84</td>
+   </tr><tr>
+      <td class="tdc bl">1.59</td>
+      <td class="tdc bl">1.0072</td>
+      <td class="tdc bl br">1.87</td>
+   </tr><tr>
+      <td class="tdc bl">1.61</td>
+      <td class="tdc bl">1.0073</td>
+      <td class="tdc bl br">1.90</td>
+   </tr><tr>
+      <td class="tdc bl">1.64</td>
+      <td class="tdc bl">1.0074</td>
+      <td class="tdc bl br">1.92</td>
+   </tr><tr>
+      <td class="tdc bl">1.66</td>
+      <td class="tdc bl">1.0075</td>
+      <td class="tdc bl br">1.95</td>
+   </tr><tr>
+      <td class="tdc bl">1.68</td>
+      <td class="tdc bl">1.0076</td>
+      <td class="tdc bl br">1.97</td>
+   </tr><tr>
+      <td class="tdc bl">1.70</td>
+      <td class="tdc bl">1.0077</td>
+      <td class="tdc bl br">2.00</td>
+   </tr><tr>
+      <td class="tdc bl">1.72</td>
+      <td class="tdc bl">1.0078</td>
+      <td class="tdc bl br">2.02</td>
+   </tr><tr>
+      <td class="tdc bl bb">1.75</td>
+      <td class="tdc bl bb">1.0079</td>
+      <td class="tdc bl br bb">2.05</td>
+   </tr><tr>
+      <td class="tdc bl">1.77</td>
+      <td class="tdc bl">1.0080</td>
+      <td class="tdc bl br">2.07</td>
+   </tr><tr>
+      <td class="tdc bl">1.79</td>
+      <td class="tdc bl">1.0081</td>
+      <td class="tdc bl br">2.10</td>
+   </tr><tr>
+      <td class="tdc bl">1.82</td>
+      <td class="tdc bl">1.0082</td>
+      <td class="tdc bl br">2.12</td>
+   </tr><tr>
+      <td class="tdc bl">1.84</td>
+      <td class="tdc bl">1.0083</td>
+      <td class="tdc bl br">2.15</td>
+   </tr><tr>
+      <td class="tdc bl">1.86</td>
+      <td class="tdc bl">1.0084</td>
+      <td class="tdc bl br">2.17</td>
+   </tr><tr>
+      <td class="tdc bl">1.88</td>
+      <td class="tdc bl">1.0085</td>
+      <td class="tdc bl br">2.20</td>
+   </tr><tr>
+      <td class="tdc bl">1.90</td>
+      <td class="tdc bl">1.0086</td>
+      <td class="tdc bl br">2.23</td>
+   </tr><tr>
+      <td class="tdc bl">1.92</td>
+      <td class="tdc bl">1.0087</td>
+      <td class="tdc bl br">2.25</td>
+   </tr><tr>
+      <td class="tdc bl">1.94</td>
+      <td class="tdc bl">1.0088</td>
+      <td class="tdc bl br">2.28</td>
+   </tr><tr>
+      <td class="tdc bl bb">1.96</td>
+      <td class="tdc bl bb">1.0089</td>
+      <td class="tdc bl br bb">2.30</td>
+   </tr><tr>
+      <td class="tdc bl">1.98</td>
+      <td class="tdc bl">1.0090</td>
+      <td class="tdc bl br">2.33</td>
+   </tr><tr>
+      <td class="tdc bl">2.00</td>
+      <td class="tdc bl">1.0091</td>
+      <td class="tdc bl br">2.35</td>
+   </tr><tr>
+      <td class="tdc bl">2.03</td>
+      <td class="tdc bl">1.0092</td>
+      <td class="tdc bl br">2.38</td>
+   </tr><tr>
+      <td class="tdc bl">2.05</td>
+      <td class="tdc bl">1.0093</td>
+      <td class="tdc bl br">2.41</td>
+   </tr><tr>
+      <td class="tdc bl">2.07</td>
+      <td class="tdc bl">1.0094</td>
+      <td class="tdc bl br">2.43</td>
+   </tr><tr>
+      <td class="tdc bl">2.09</td>
+      <td class="tdc bl">1.0095</td>
+      <td class="tdc bl br">2.46</td>
+   </tr><tr>
+      <td class="tdc bl">2.11</td>
+      <td class="tdc bl">1.0096</td>
+      <td class="tdc bl br">2.48</td>
+   </tr><tr>
+      <td class="tdc bl">2.14</td>
+      <td class="tdc bl">1.0097</td>
+      <td class="tdc bl br">2.51</td>
+   </tr><tr>
+      <td class="tdc bl">2.16</td>
+      <td class="tdc bl">1.0098</td>
+      <td class="tdc bl br">2.53</td>
+   </tr><tr>
+      <td class="tdc bl bb">2.18</td>
+      <td class="tdc bl bb">1.0099</td>
+      <td class="tdc bl br bb">2.56</td>
+   </tr><tr>
+      <td class="tdc bl">2.21</td>
+      <td class="tdc bl">1.0100</td>
+      <td class="tdc bl br">2.58</td>
+   </tr><tr>
+      <td class="tdc bl">2.23</td>
+      <td class="tdc bl">1.0101</td>
+      <td class="tdc bl br">2.61</td>
+   </tr><tr>
+      <td class="tdc bl">2.25</td>
+      <td class="tdc bl">1.0102</td>
+      <td class="tdc bl br">2.64</td>
+   </tr><tr>
+      <td class="tdc bl">2.27</td>
+      <td class="tdc bl">1.0103</td>
+      <td class="tdc bl br">2.66</td>
+   </tr><tr>
+      <td class="tdc bl">2.30</td>
+      <td class="tdc bl">1.0104</td>
+      <td class="tdc bl br">2.69</td>
+   </tr><tr>
+      <td class="tdc bl">2.32</td>
+      <td class="tdc bl">1.0105</td>
+      <td class="tdc bl br">2.71</td>
+   </tr><tr>
+      <td class="tdc bl">2.34</td>
+      <td class="tdc bl">1.0106</td>
+      <td class="tdc bl br">2.74</td>
+   </tr><tr>
+      <td class="tdc bl">2.36</td>
+      <td class="tdc bl">1.0107</td>
+      <td class="tdc bl br">2.76</td>
+   </tr><tr>
+      <td class="tdc bl">2.38</td>
+      <td class="tdc bl">1.0108</td>
+      <td class="tdc bl br">2.79</td>
+   </tr><tr>
+      <td class="tdc bl bb">2.40</td>
+      <td class="tdc bl bb">1.0109</td>
+      <td class="tdc bl br bb">2.82</td>
+   </tr><tr>
+      <td class="tdc bl">2.42</td>
+      <td class="tdc bl">1.0110</td>
+      <td class="tdc bl br">2.84</td>
+   </tr><tr>
+      <td class="tdc bl">2.44</td>
+      <td class="tdc bl">1.0111</td>
+      <td class="tdc bl br">2.87</td>
+   </tr><tr>
+      <td class="tdc bl">2.46</td>
+      <td class="tdc bl">1.0112</td>
+      <td class="tdc bl br">2.89</td>
+   </tr><tr>
+      <td class="tdc bl">2.48</td>
+      <td class="tdc bl">1.0113</td>
+      <td class="tdc bl br">2.92</td>
+   </tr><tr>
+      <td class="tdc bl">2.50</td>
+      <td class="tdc bl">1.0114</td>
+      <td class="tdc bl br">2.94</td>
+   </tr><tr>
+      <td class="tdc bl">2.52</td>
+      <td class="tdc bl">1.0115</td>
+      <td class="tdc bl br">2.97</td>
+   </tr><tr>
+      <td class="tdc bl">2.54</td>
+      <td class="tdc bl">1.0116</td>
+      <td class="tdc bl br">2.99</td>
+   </tr><tr>
+      <td class="tdc bl">2.57</td>
+      <td class="tdc bl">1.0117</td>
+      <td class="tdc bl br">3.02</td>
+   </tr><tr>
+      <td class="tdc bl">2.59</td>
+      <td class="tdc bl">1.0118</td>
+      <td class="tdc bl br">3.05</td>
+   </tr><tr>
+      <td class="tdc bl bb">2.61</td>
+      <td class="tdc bl bb">1.0119</td>
+      <td class="tdc bl br bb">3.07</td>
+   </tr><tr>
+      <td class="tdc bl">2.64</td>
+      <td class="tdc bl">1.0120</td>
+      <td class="tdc bl br">3.10</td>
+   </tr><tr>
+      <td class="tdc bl">2.66</td>
+      <td class="tdc bl">1.0121</td>
+      <td class="tdc bl br">3.12</td>
+   </tr><tr>
+      <td class="tdc bl">2.68</td>
+      <td class="tdc bl">1.0122</td>
+      <td class="tdc bl br">3.15</td>
+   </tr><tr>
+      <td class="tdc bl">2.70</td>
+      <td class="tdc bl">1.0123</td>
+      <td class="tdc bl br">3.17</td>
+   </tr><tr>
+      <td class="tdc bl">2.72</td>
+      <td class="tdc bl">1.0124</td>
+      <td class="tdc bl br">3.20</td>
+   </tr><tr>
+      <td class="tdc bl">2.75</td>
+      <td class="tdc bl">1.0125</td>
+      <td class="tdc bl br">3.23</td>
+   </tr><tr>
+      <td class="tdc bl">2.77</td>
+      <td class="tdc bl">1.0126</td>
+      <td class="tdc bl br">3.25</td>
+   </tr><tr>
+      <td class="tdc bl">2.79</td>
+      <td class="tdc bl">1.0127</td>
+      <td class="tdc bl br">3.28</td>
+   </tr><tr>
+      <td class="tdc bl">2.82</td>
+      <td class="tdc bl">1.0128</td>
+      <td class="tdc bl br">3.30</td>
+   </tr><tr>
+      <td class="tdc bl bb">2.84</td>
+      <td class="tdc bl bb">1.0129</td>
+      <td class="tdc bl br bb">3.33</td>
+   </tr><tr>
+      <td class="tdc bl">2.86</td>
+      <td class="tdc bl">1.0130</td>
+      <td class="tdc bl br">3.35</td>
+   </tr><tr>
+      <td class="tdc bl">2.88</td>
+      <td class="tdc bl">1.0131</td>
+      <td class="tdc bl br">3.38</td>
+   </tr><tr>
+      <td class="tdc bl">2.90</td>
+      <td class="tdc bl">1.0132</td>
+      <td class="tdc bl br">3.41</td>
+   </tr><tr>
+      <td class="tdc bl">2.92</td>
+      <td class="tdc bl">1.0133</td>
+      <td class="tdc bl br">3.43</td>
+   </tr><tr>
+      <td class="tdc bl">2.94</td>
+      <td class="tdc bl">1.0134</td>
+      <td class="tdc bl br">3.46</td>
+   </tr><tr>
+      <td class="tdc bl">2.96</td>
+      <td class="tdc bl">1.0135</td>
+      <td class="tdc bl br">3.48</td>
+   </tr><tr>
+      <td class="tdc bl">2.98</td>
+      <td class="tdc bl">1.0136</td>
+      <td class="tdc bl br">3.51</td>
+   </tr><tr>
+      <td class="tdc bl bb">3.00</td>
+      <td class="tdc bl bb">1.0137</td>
+      <td class="tdc bl br bb">3.54</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>If it be desired to use this table for the examination of liquors
+containing a higher percentage of extract, Schultze’s table (intended
+originally for wort) may be consulted.</p>
+
+<p>Gautier regards the fixed solids as the residue obtained on
+evaporating, in a flat platinum dish, ten cubic centimeters of wine at
+100° for four hours and a half.<a id="FNanchor_639" href="#Footnote_639" class="fnanchor">[639]</a></p>
+
+<p><span class="pagenum"><a id="Page_626"></a>[Pg 626]</span>
+The official French method is as follows: Twenty cubic centimeters of
+wine are placed in a flat bottom, platinum dish of such a diameter
+that the depth of the liquid therein does not exceed one millimeter.
+The dish should be immersed as totally as possible in the steam. The
+heating is continued for six hours.</p>
+
+<p>The following method is used at the municipal laboratory of Paris:</p>
+
+<p>Twenty-five cubic centimeters of wine are placed in a flat bottom,
+platinum dish seventy millimeters in diameter and twenty-five deep. The
+dish is placed on a water bath in such a manner that it just touches
+the surface of the water which is kept at a constant level. The heating
+is continued for seven hours.<a id="FNanchor_640" href="#Footnote_640" class="fnanchor">[640]</a></p>
+
+<p><b>625. Determination in a Vacuum.</b>—To avoid the changes and
+decomposition produced by heating, the fixed solids may also be
+determined by drying the sample in a vacuum over sulfuric acid. In
+this laboratory, it has been found that the process may be greatly
+facilitated by connecting the desiccating apparatus with the vacuum
+service of the working desks in which a vacuum corresponding to a
+mercurial column of 600 millimeters is obtained. The desiccator is
+provided with a valve whereby a minute current of dry air is allowed
+to flow through it. This current is not large enough to lessen the
+vacuum but is sufficient to greatly accelerate the rapidity of the
+evaporation. The evaporation is hastened also, in a marked degree, by
+absorbing the liquid with a piece of filter paper previously dried in a
+vacuum. When it is desired to examine the residue, however, it must be
+obtained in a flat dish exposing a large surface to evaporation.</p>
+
+<p><b>626. Estimation of Water.</b>—It is evident that the percentage of
+water in a fermented beverage is easily calculated when the percentage
+of alcohol by weight and that of the dry residue are known. In a given
+case, if the number of grams of alcohol in 100 of the sample be five
+and that of fixed solids four and a half, the quantity of water therein
+is 100 - (5.0 + 4.5) = 90.5 grams. In this case the volatile essences
+are counted as water, but these, at most, are so small in quantity as
+to be practically unweighable. Nevertheless, it must be admitted that
+<span class="pagenum"><a id="Page_627"></a>[Pg 627]</span>
+direct drying, in many cases, may give erroneous results, especially
+when the sample contains an abundance of ethers and of glycerol. The
+loss which takes place on evaporation may be diminished by adding to
+the sample, before evaporation, a known weight of potassium sulfate
+in crystals, which serves to increase the surface of evaporation, to
+hasten the process and to obtain a quantity of residue in excess of
+that secured by direct evaporation in an open dish.</p>
+
+<p><b>627. Total Acidity.</b>—The acidity found in fermented beverages
+is due both to the natural acids of the materials from which they are
+made, and to those caused by fermentation. The typical acids also
+indicate the nature of the original materials, as malic in cider and
+tartaric in wine. The acids of beers are due almost exclusively to
+fermentation, and acetic is probably the dominant one. In determining
+total acidity, it is not always convenient to ascertain beforehand what
+acid predominates, nor to accurately distribute the acid among its
+various components. In the analytical work it is advisable, therefore,
+to estimate the total acid of cider as malic, of wines as tartaric and
+of beers as acetic. The process of titration is conducted as follows:</p>
+
+<p>Expel any carbon dioxid that is present by continued shaking. Transfer
+ten cubic centimeters to a beaker and, in the case of white wines, add
+about ten drops of a neutral litmus solution. Add decinormal sodium
+hydroxid solution until the red color changes to violet. Then add the
+reagent, a few drops at a time, until a drop of the liquid, placed on
+delicate red litmus paper, shows an alkaline reaction.</p>
+
+<p>One cubic centimeter of decinormal sodium hydroxid solution = 0.0075
+gram tartaric, 0.0067 of malic and 0.006 gram of acetic acid.</p>
+
+<p><b>628. Determination of Volatile Acids.</b>—Fifty cubic centimeters
+of the sample, to which a little tannin has been added to prevent
+foaming, are distilled in a current of steam. The flask is heated until
+the liquid boils, when the lamp under it is turned down and the steam
+passed through until 200 cubic centimeters have been collected in the
+<span class="pagenum"><a id="Page_628"></a>[Pg 628]</span>
+receiver. The distillate is titrated with decinormal sodium hydroxid
+solution and the result expressed as acetic acid.</p>
+
+<p>One cubic centimeter of decinormal sodium hydroxid solution = 0.0060
+gram acetic acid.</p>
+
+<p>The acidity due to volatile acids may be determined by ascertaining the
+total acidity as above described, evaporating 100 cubic centimeters to
+one-third of their volume, restoring the original volume with water and
+again titrating. The difference between the first and second titrations
+represents the volatile acidity.</p>
+
+<p>A method of determining volatile acidity in wines, without the
+application of heat, has been proposed by de la Source.<a id="FNanchor_641" href="#Footnote_641" class="fnanchor">[641]</a>
+The sample, five cubic centimeters, freed of carbon dioxid by shaking,
+is placed in a flat dish about eight centimeters in diameter. In a
+separate portion of the sample, the total acidity is determined in the
+presence of phenolphthalien by a set solution of barium hydroxid, one
+cubic centimeter of which is equal to four milligrams of sulfuric acid.
+The sample in the flat dish is placed in a desiccator, which contains
+both sulfuric acid and solid potassium hydroxid, and left for two days,
+by which time it is practically dry. The residue is dissolved in two
+cubic centimeters of warm water and the dish is kept in the desiccator
+for an additional two days. By this time the volatile acids, even
+acetic, will have disappeared and the residual acidity is determined
+after solution in water.</p>
+
+<p>The method is also applicable when wines have been treated with an
+alkali. In this case two samples of five cubic centimeters each are
+acidified with two cubic centimeters of a solution of tartaric acid
+containing twenty-five grams per liter. This treatment sets free the
+volatile acids, and their quantity is determined as before.</p>
+
+<p><b>629. Titration with Phenolphthalien.</b>—The total acidity is also
+easily determined by titration with a set alkali, using phenolphthalien
+as indicator. Colored liquors must be treated with animal black before
+the analysis. The sample is shaken to expel carbon dioxid and five
+cubic centimeters added to 100 of water containing phenolphthalien. The
+<span class="pagenum"><a id="Page_629"></a>[Pg 629]</span>
+set alkali (tenth normal soda) is added until the red color is
+discharged. Even wines having a considerable degree of color may be
+titrated in this way.<a id="FNanchor_642" href="#Footnote_642" class="fnanchor">[642]</a>
+The acidity, expressed as tartaric, may be stated as due to sulfuric by
+dividing by 1.53.</p>
+
+<p><b>630. Determination of Tartaric Acid.</b>—The determination of
+potassium bitartrate is necessary when an estimation of the free
+tartaric acid is desired.<a id="FNanchor_643" href="#Footnote_643" class="fnanchor">[643]</a></p>
+
+<p>Fifty cubic centimeters of wine are placed in a porcelain dish and
+evaporated to a sirupy consistence, a little quartz sand being added
+to render subsequent extraction easier. After cooling, seventy cubic
+centimeters of ninety-six per cent alcohol are added with constant
+stirring. After standing for twelve hours, at as low a temperature as
+practicable, the solution is filtered and the precipitate washed with
+alcohol until the filtrate is no longer acid. The alcoholic filtrate
+is preserved for the estimation of the tartaric acid. The filter and
+precipitate are returned to the porcelain dish and repeatedly treated
+with hot water, each extraction being filtered into a flask or beaker
+until the washings are neutral. The combined aqueous filtrates and
+washings are titrated with decinormal sodium hydroxid solution.</p>
+
+<p>One cubic centimeter of decinormal sodium hydroxid solution = 0.0188
+gram potassium bitartrate.</p>
+
+<p>The alcoholic filtrate is made up to a definite volume with water and
+divided into two equal portions. One portion is exactly neutralized
+with decinormal sodium hydroxid solution, the other portion added,
+the alcohol evaporated, the residue washed into a porcelain dish and
+treated as above.</p>
+
+<p>One cubic centimeter decinormal sodium hydroxid solution = 0.0075 gram
+tartaric acid.</p>
+
+<p>As, however, only half of the free tartaric acid is determined by this
+method:</p>
+
+<p>One cubic centimeter decinormal sodium hydroxid = 0.0150 gram of
+tartaric acid.</p>
+
+<p><b>631. Modified Berthelot-Fleury Method.</b>—Ten cubic centimeters of
+wine are neutralized with potassium hydroxid solution and mixed in a
+graduated cylinder with forty cubic centimeters of the same sample. To
+<span class="pagenum"><a id="Page_630"></a>[Pg 630]</span>
+one-fifth of the volume, corresponding to ten cubic centimeters of
+wine, fifty cubic centimeters of a mixture of equal parts of alcohol
+and ether are added and allowed to stand twenty-four hours. The
+precipitated potassium bitartrate is separated by filtration, dissolved
+in water and titrated. The excess of potassium bitartrate over the
+amount of that constituent present in the wine corresponds to the free
+tartaric acid.<a id="FNanchor_644" href="#Footnote_644" class="fnanchor">[644]</a></p>
+
+<p><b>632. Determination of Tartaric, Malic and Succinic Acids.</b>—Two
+hundred cubic centimeters of wine are evaporated to one-half, cooled
+and lead subacetate solution added until the reaction is alkaline.<a id="FNanchor_645" href="#Footnote_645" class="fnanchor">[645]</a>
+The precipitate is separated by filtration and washed with cold
+water until the filtrate shows only a slight reaction for lead.
+The precipitate is washed from the filter into a beaker, by means
+of hot water, and treated hot with hydrogen sulfid until all the
+lead is converted into sulfid. It is then filtered hot and the lead
+sulfid washed with hot water until the washings are no longer acid.
+The filtrate and washings are evaporated to fifty cubic centimeters
+and accurately neutralized with potassium hydroxid. An excess of a
+saturated solution of calcium acetate is added and the liquid allowed
+to stand from four to six hours with frequent stirring. It is then
+filtered and the precipitate washed until the filtrate amounts to
+exactly 100 cubic centimeters. The precipitate of calcium tartrate is
+converted into calcium oxid by igniting in a platinum crucible. After
+cooling, from ten to fifteen cubic centimeters of normal hydrochloric
+acid are added, the solution washed into a beaker and accurately
+titrated with normal potassium hydroxid solution. Every cubic
+centimeter of normal acid saturated by the calcium oxid is equivalent
+to 0.0750 gram tartaric acid. To the amount so obtained, 0.0286 gram
+must be added, representing the tartaric acid held in solution in the
+filtrate as calcium tartrate. The sum represents the total tartaric
+acid in the wine.</p>
+
+<p>The filtrate from the calcium tartrate is evaporated to about
+twenty-five cubic centimeters, cooled and mixed with three times its
+volume of ninety-six per cent alcohol. After standing several hours,
+the precipitate is collected on a weighed filter, dried at 100° and
+weighed. It represents the calcium salts of malic, succinic and
+<span class="pagenum"><a id="Page_631"></a>[Pg 631]</span>
+sulfuric acids and of the tartaric acid which remained in solution.
+This precipitate is dissolved in a minimum quantity of hydrochloric
+acid, filtered and the filter washed with hot water. Potassium
+carbonate solution is added to the hot filtrate, and the precipitated
+calcium carbonate separated by filtration and washed. The filtrate
+contains the potassium salts of the above named acids. It is
+neutralized with acetic acid, evaporated to a small volume and
+precipitated hot with barium chlorid. The precipitate of barium
+succinate and sulfate is separated by filtration, washed with hot
+water and treated on the filter with dilute hydrochloric acid. The
+barium sulfate remaining is washed, dried, ignited and weighed. In
+the filtrate, which contains the barium succinate, the barium is
+precipitated hot with sulfuric acid, washed, dried, ignited and
+weighed. Two hundred and twenty-three parts of barium sulfate equal 118
+parts of succinic acid. The succinic and sulfuric acids, as well as the
+tartaric acid remaining in solution, which is equal to 0.0286 gram,
+are to be calculated as calcium salts and the result deducted from the
+total weight of the calcium precipitate. The remainder is the calcium
+malate, of which 172 parts equal 134 parts malic acid.</p>
+
+<p>According to Macagno, succinic acid may be estimated in wines by the
+following process:<a id="FNanchor_646" href="#Footnote_646" class="fnanchor">[646]</a>
+One liter of the wine is digested with lead hydroxid, evaporated on the
+water bath and the residue extracted with strong alcohol. The residual
+salts of lead are boiled with a ten per cent solution of ammonium
+nitrate, which dissolves the salts of succinic acid. The solution is
+filtered, the lead removed by hydrogen sulfid, boiled, neutralized
+with ammonia and treated with ferric chlorid as long as a precipitate
+is formed. The ferric succinate is separated by filtration, washed and
+ignited. The succinic acid is calculated from the weight of ferric oxid
+obtained.</p>
+
+<p>Malic acid in wines and ciders is determined by the method of Berthelot
+in the following manner:<a id="FNanchor_647" href="#Footnote_647" class="fnanchor">[647]</a>
+The sample is evaporated until reduced to a tenth of its volume. To
+the residue an equal volume of ninety per cent alcohol is added and
+the mixture set aside for some time. The tartaric acid and tartrates
+separate, together with the greater part of the salts of lime which may
+be present.
+<span class="pagenum"><a id="Page_632"></a>[Pg 632]</span></p>
+
+<p>The supernatant liquid is decanted and a small quantity of lime
+added to it until in slight excess of that required to neutralize
+the acidity. Calcium malate is separated mixed with lime. The solid
+matters are separated by filtration, dissolved in a ten per cent
+solution of nitric acid, from which the lime bimalate will separate in
+a crystalline form. The weight of calcium bimalate multiplied by 0.59
+gives that of the malic acid.</p>
+
+<p><b>633. Polarizing Bodies in Fermented Beverages.</b>—The study of
+the nature of the carbohydrates, which constitute an important part of
+the solid matters dissolved in fermented beverages, is of the greatest
+importance. These bodies consist of grape sugars, sucrose, tartaric
+acid and the unfermented hydrolytic products derived from starch. A
+natural grape sugar (chiefly dextrose) is found in wines. Sucrose
+is also a very important constituent of sweet wines. The hydrolytic
+products of starch are found in beers, either as a residue from the
+fermentation of malt or from the rice, glucose, hominy grits etc.,
+added in brewing. The character and quantities of these residues can
+be determined by the methods already given in the parts of this volume
+relating to sugars and starches. For convenience, however, and for
+special application to the investigation of fermented beverages a
+résumé of the methods adopted by the official chemists follows:<a id="FNanchor_648" href="#Footnote_648" class="fnanchor">[648]</a></p>
+
+<p><b>634. Determination of Reducing Sugars.</b>—The reducing sugars are
+estimated as dextrose, and may be determined by any of the methods
+given for the estimation thereof (<b><a href="#P_113">113-140</a></b>).</p>
+
+<p><b>635. Polarization.</b>—All results are to be stated as the
+polarization of the undiluted sample. The triple field shadow
+saccharimeter is recommended, and the results are expressed in the
+terms of the sugar scale of this instrument. If any other instrument
+be used, or if it be desirable to convert to angular rotation, the
+following factors may be employed:</p>
+
+<table class="spb1 fs_90">
+   <tbody><tr>
+      <td class="tdl">1° Schmidt and Haensch</td>
+      <td class="tdl_wsp">= 0°.3468</td>
+      <td class="tdl_wsp">angular rotation D.</td>
+   </tr><tr>
+      <td class="tdl">1° angular rotation D</td>
+      <td class="tdl_wsp">= 2°.8835</td>
+      <td class="tdl_wsp">Schmidt and Haensch.</td>
+   </tr><tr>
+      <td class="tdl">1° Schmidt and Haensch</td>
+      <td class="tdl_wsp">= 2°.6048</td>
+      <td class="tdl_wsp">Wild (sugar scale).</td>
+   </tr><tr>
+      <td class="tdl">1° Wild (sugar scale)</td>
+      <td class="tdl_wsp">= 0°.3840</td>
+      <td class="tdl_wsp">Schmidt and Haensch.</td>
+   </tr><tr>
+      <td class="tdl">1° Wild (sugar scale)</td>
+      <td class="tdl_wsp">= 0°.1331</td>
+      <td class="tdl_wsp">angular rotation D.</td>
+   </tr><tr>
+      <td class="tdl">1° angular rotation D</td>
+      <td class="tdl_wsp">= 0°.7511</td>
+      <td class="tdl_wsp">Wild (sugar scale).</td>
+   </tr><tr>
+      <td class="tdl">1° Laurent (sugar scale)</td>
+      <td class="tdl_wsp">= 0°.2167</td>
+      <td class="tdl_wsp">angular rotation D.</td>
+   </tr><tr>
+      <td class="tdl">1° angular rotation D</td>
+      <td class="tdl_wsp">= 4°.6154</td>
+      <td class="tdl_wsp">Laurent (sugar scale).</td>
+   </tr>
+ </tbody>
+</table>
+
+<p><span class="pagenum"><a id="Page_633"></a>[Pg 633]</span>
+In the above table D represents the angular rotation produced with
+yellow monochromatic light.</p>
+
+<p>(<i>a</i>) <i>In White Wines or Beers.</i>—Sixty cubic centimeters of
+wine are decolorized with three cubic centimeters of lead subacetate
+solution and filtered. Thirty cubic centimeters of the filtrate are
+treated with one and five-tenths cubic centimeters of a saturated
+solution of sodium carbonate, filtered and polarized. This gives a
+solution of nearly ten to eleven, which must be considered in the
+calculation, and the polariscope reading must accordingly be increased
+one-tenth.</p>
+
+<p>(<i>b</i>) <i>In Red Wines.</i>—Sixty cubic centimeters of wine are
+decolorized with six cubic centimeters of lead subacetate solution and
+filtered. To thirty cubic centimeters of the filtrate, three cubic
+centimeters of a saturated solution of sodium carbonate are added,
+filtered and the filtrate polarized. The dilution in this case is
+nearly five to six, and the polariscope reading must accordingly be
+increased one-fifth.</p>
+
+<p>(<i>c</i>) <i>In Sweet Wines.</i> (1) <i>Before Inversion.</i>—One
+hundred cubic centimeters are decolorized with two cubic centimeters of
+lead subacetate solution and filtered after the addition of eight cubic
+centimeters of water. One-half cubic centimeter of a saturated solution
+of sodium carbonate and four and five-tenths cubic centimeters of water
+are added to fifty-five cubic centimeters of the filtrate, the liquids
+mixed, filtered and polarized. The polariscope reading is multiplied by 1.2.</p>
+
+<p>(2) <i>After Inversion.</i>—Thirty-three cubic centimeters of the
+filtrate from the lead subacetate in (1) are placed in a flask with
+three cubic centimeters of strong hydrochloric acid. After mixing
+well, the flask is placed in water and heated until a thermometer,
+placed in the flask with the bulb as near the center of the liquid as
+possible, marks 68°, consuming about fifteen minutes in the heating.
+It is then removed, cooled quickly to room temperature, filtered and
+polarized, the temperature being noted. The polariscope reading is
+multiplied by 1.2. Because of the action of lead subacetate on invert
+sugar (<b><a href="#P_87">87</a></b>) it is advisable to decolorize the
+samples with other reagents (<b><a href="#P_87">87-89</a></b>).</p>
+
+<p>(3) <i>After Fermentation.</i>—Fifty cubic centimeters of wine, which
+<span class="pagenum"><a id="Page_634"></a>[Pg 634]</span>
+have been dealcoholized by evaporation and made up to the original
+volume with water, are mixed, in a small flask, with well washed
+beer yeast and kept at 30° until fermentation has ceased, which
+requires from two to three days. The liquid is washed into a 100 cubic
+centimeter flask, a few drops of a solution of acid mercuric nitrate
+and then lead subacetate solution, followed by sodium carbonate, added.
+The flask is filled to the mark with water, shaken, the solution
+filtered and polarized and the reading multiplied by two.</p>
+
+<p><b>636. Application of Analytical Methods.</b>—(1) <i>There is no
+rotation.</i>—This may be due to the absence of any rotatory body,
+to the simultaneous presence of the dextrorotatory nonfermentable
+constituents of commercial dextrose and levorotatory sugar, or to the
+simultaneous presence of dextrorotatory cane sugar and levorotatory
+invert sugar.</p>
+
+<p>(<i>a</i>) <i>The Wine is Inverted.</i>—A levorotation shows that the
+sample contains cane sugar.</p>
+
+<p>(<i>b</i>) <i>The Wine is Fermented.</i>—A dextrorotation shows
+that both levorotatory sugar and the unfermentable constituents of
+commercial dextrose are present.</p>
+
+<p>If no change take place in either (<i>a</i>) or (<i>b</i>) in the
+rotation, it proves the absence of unfermented cane sugar, the unfermentable
+constituents of commercial dextrose and of levorotatory sugar.</p>
+
+<p>(2) <i>There is right rotation.</i>—This may be caused by unfermented
+cane sugar, the unfermentable constituents of commercial dextrose or both.</p>
+
+<p>(<i>a</i>) The sugar is inverted:</p>
+
+<p>(<i>a</i>₁) <i>It rotates to the left after inversion.</i>—Unfermented
+cane sugar is present.</p>
+
+<p>(<i>a</i>₂) <i>It rotates more than 2°.3 to the right.</i>—The
+unfermentable constituents of commercial dextrose are present.</p>
+
+<p>(<i>a</i>₃) <i>It rotates less than 2°.3 and more than 0°.9 to the
+right.</i>—It is in this case treated as follows:</p>
+
+<p>Two hundred and ten cubic centimeters of the sample are evaporated to a
+thin sirup with a few drops of a twenty per cent solution of potassium
+acetate. To the residue 200 cubic centimeters of ninety per cent
+alcohol are added with constant stirring. The alcoholic solution is
+<span class="pagenum"><a id="Page_635"></a>[Pg 635]</span>
+filtered into a flask and the alcohol removed by distillation until
+about five cubic centimeters remain. The residue is mixed with washed
+bone-black, filtered into a graduated cylinder and washed until the
+filtrate amounts to thirty cubic centimeters. When the filtrate shows
+a dextrorotation of more than 1°.5, it indicates the presence of
+unfermentable constituents of commercial dextrose.</p>
+
+<p>(3) <i>There is left rotation.</i>—The sample contains unfermented
+levorotatory sugar, derived either from the must or mash or from
+the inversion of added cane sugar. It may, however, also contain
+unfermented cane sugar and the unfermentable constituents of commercial
+dextrose.</p>
+
+<p>(<i>a</i>) The wine sugars are fermented according to directions in
+<b><a href="#P_262">262</a></b>.</p>
+
+<p>(<i>a</i>₁) <i>It polarizes 3° after fermentation.</i>—It contains
+only levorotatory sugar.</p>
+
+<p>(<i>a</i>₂) <i>It rotates to the right.</i>— It contains both
+levorotatory sugar and the unfermentable constituents of commercial
+dextrose.</p>
+
+<p>(<i>b</i>₁) The sucrose is inverted according to (<i>c</i>), in (2).</p>
+
+<p>(<i>b</i>₂) It is more strongly levorotatory after inversion. In
+contains both levorotatory sugar and unfermented cane sugar.</p>
+
+<p><b>637. Estimation of Sucrose, Dextrose, Invert Sugar, Maltose and
+Dextrin.</b>—The total and relative quantities of these carbohydrates
+are determined by the processes already described (<b><a href="#P_237">237-262</a></b>).</p>
+
+<p><b>638. Determination of Glycerol.</b>—(<i>a</i>) <i>In Dry Wines
+and Beers.</i>—One hundred cubic centimeters of wine are evaporated
+in a porcelain dish to about ten cubic centimeters, a little quartz
+sand and milk of lime added and the evaporation carried almost to
+dryness. The residue is mixed with fifty cubic centimeters of ninety
+per cent alcohol, using a glass pestle or spatula to break up any solid
+particles, heated to boiling on the water bath, allowed to settle and
+the liquid filtered into a small flask. The residue is repeatedly
+extracted in a similar manner, with small portions of boiling alcohol,
+until the filtrate in the flask amounts to about 150 cubic centimeters.
+A little quartz sand is added, the flask connected with a condenser and
+<span class="pagenum"><a id="Page_636"></a>[Pg 636]</span>
+the alcohol slowly distilled until about ten cubic centimeters remain.
+The evaporation is continued on the water bath until the residue
+becomes sirupy. It is cooled and dissolved in ten cubic centimeters of
+absolute alcohol. The solution may be facilitated by gentle heating
+on the steam bath. Fifteen cubic centimeters of anhydrous ether are
+added, the flask stoppered and allowed to stand until the precipitate
+has collected on the sides and bottom of the flask. The clear liquid
+is decanted into a tared weighing bottle, the precipitate repeatedly
+washed with a few cubic centimeters of a mixture of one part of
+absolute alcohol and one and five-tenths parts anhydrous ether and the
+washings added to the solution. The ether-alcohol is evaporated on
+the steam bath, the residue dried one hour in a water oven, weighed,
+the amount of ash determined and its weight deducted from that of the
+weighed residue to get the quantity of glycerol.</p>
+
+<p>(<i>b</i>) <i>In Sweet Wines.</i>—One hundred cubic centimeters of
+wine are evaporated on the steam bath to a sirupy consistence, a little
+quartz sand being added to render subsequent extraction easier. The
+residue is repeatedly treated with absolute alcohol until the united
+extracts amount to from 100 to 150 cubic centimeters. The solution is
+collected in a flask and for every part of alcohol one and five-tenths
+parts of ether are added, the liquid well shaken and allowed to stand
+until it becomes clear. The supernatant liquor is decanted into a
+beaker and the precipitate washed with a few cubic centimeters of
+a mixture of one part alcohol and one and five-tenths parts ether.
+The united liquids are distilled, the evaporation being finished on
+the water bath, the residue is dissolved in water, transferred to a
+porcelain dish and treated as under (<i>a</i>).</p>
+
+<p><b>639. Determination of Coloring Matters in Wines.</b>—The methods
+of detecting the more commonly occurring coloring matters in wines as
+practiced by the official chemists are given below.</p>
+
+<p>(<i>a</i>) <i>Cazeneuve Reaction.</i>—Add two-tenths gram of
+precipitated mercuric oxid to ten cubic centimeters of wine, shake for
+one minute and filter.</p>
+
+<p>Pure wines give filtrates which are colorless or light yellow, while
+the presence of a more or less red coloration indicates that an anilin
+color has been added to the wine.
+<span class="pagenum"><a id="Page_637"></a>[Pg 637]</span></p>
+
+<p>(<i>b</i>) <i>Method of Sostegni and Carpentieri.</i>—Evaporate the
+alcohol from 200 cubic centimeters of wine. Add from two to four cubic
+centimeters of a ten per cent solution of hyrochloric acid, immerse
+therein some threads of fat-free wool and boil for five minutes. Remove
+the threads, wash them with cold water acidified with hydrochloric,
+then with hot water acidified with hydrochloric, then with pure water
+and dissolve the color in a boiling mixture of fifty cubic centimeters
+of water and two cubic centimeters of concentrated ammonia. Replace
+the threads by new ones, acidify with hydrochloric and boil again for
+five minutes. In the presence of anilin colors to the amount of two
+milligrams per liter, the threads are dyed as follows:</p>
+
+<table class="spb1">
+   <tbody><tr>
+      <td class="tdl">Safranin</td>
+      <td class="tdr">light rose-red.</td>
+   </tr><tr>
+      <td class="tdl">Vinolin</td>
+      <td class="tdr">rose-red to violet.</td>
+   </tr><tr>
+      <td class="tdl">Bordeaux-red&emsp;&nbsp;</td>
+      <td class="tdr">rose-red to violet.</td>
+   </tr><tr>
+      <td class="tdl">Ponceau-red</td>
+      <td class="tdr">rose-red.</td>
+   </tr><tr>
+      <td class="tdl">Tropæolin oo</td>
+      <td class="tdr">straw yellow.</td>
+   </tr><tr>
+      <td class="tdl">Tropæolin ooo</td>
+      <td class="tdr">light orange.</td>
+   </tr>
+ </tbody>
+</table>
+
+<p>(<i>c</i>) <i>Detection of Fuchsin and Orseille.</i>—To twenty cubic
+centimeters of wine add ten cubic centimeters of lead acetate solution,
+heat slightly and mix by shaking. Filter into a test-tube, add two
+cubic centimeters of amyl alcohol and shake. If the amyl alcohol be
+colored red, separate it and divide it into two portions. To one add
+hydrochloric acid, to the other ammonia. When the color is due to
+fuchsin, the amyl alcohol will in both cases be decolorized; when due
+to orseille, the ammonia will change the color of the amyl alcohol to
+purple-violet.</p>
+
+<p><b>640. Determination of Ash.</b>—The residue from the direct extract
+determination is incinerated at as low a heat as possible. Repeated
+moistening, drying and heating to low redness is advisable to get rid
+of all organic substances. When a quantitive analysis of the ash is
+desired, large quantities of the sample are evaporated to dryness and
+the residue incinerated with the usual precautions.</p>
+
+<p><b>641. Determination Of Potash.</b>—(<i>a</i>) <i>Kayser’s
+Method.</i>—Dissolve seven-tenths gram pure sodium hydroxid and two
+grams of tartaric acid in 100 cubic centimeters of wine, add 150 cubic
+<span class="pagenum"><a id="Page_638"></a>[Pg 638]</span>
+centimeters of ninety-two to ninety-four per cent alcohol and allow
+the liquid to stand twenty-four hours. The precipitated potassium
+bitartrate is collected on a small filter and washed with fifty per
+cent alcohol until the filtrate amounts to 260 cubic centimeters. The
+precipitate and filter are transferred to the beaker in which the
+precipitation was made, the precipitate dissolved in hot water, the
+volume made up to 200 cubic centimeters and fifty cubic centimeters
+thereof titrated with decinormal sodium hydroxid solution, adding 0.004
+gram to the final result, representing the potash which remains in
+solution as bitartrate.</p>
+
+<p>(<i>b</i>) <i>Platinum Chlorid Method.</i>—Evaporate 100 cubic
+centimeters of the wine to dryness, incinerate the residue and
+determine the potash as in ash analysis.<a id="FNanchor_649" href="#Footnote_649" class="fnanchor">[649]</a></p>
+
+<p><b>642. Determination of Sulfurous Acid.</b>—One hundred cubic
+centimeters of wine are distilled in a current of carbon dioxid, after
+the addition of phosphoric acid, until about fifty cubic centimeters
+have passed over. The distillate is collected in accurately set iodin
+solution. When the distillation is finished, the excess of iodin is
+determined with set sodium thiosulfate solution and the sulfurous acid
+calculated from the iodin used.</p>
+
+<p><b>643. Detection of Salicylic Acid.</b>—(<i>a</i>) <i>Spica’s
+Method.</i>—Acidify 100 cubic centimeters of the liquor with sulfuric
+and extract with sulfuric ether. Evaporate the extract to dryness, warm
+the residue carefully with one drop of concentrated nitric acid and add
+two or three drops of ammonia. The presence of salicylic acid in the
+liquor is indicated by the formation of a yellow color due to ammonium
+picrate and may be confirmed by dyeing therein a thread of fat-free wool.</p>
+
+<p>(<i>b</i>) <i>Bigelow’s Method.</i>—Place 100 cubic centimeters of the
+wine in a separatory funnel, add five cubic centimeters of sulfuric
+acid (1-3) and extract with a sufficient quantity of a mixture of eight
+or nine parts of ether to one part of petroleum ether. Throw away the
+aqueous part of the extract, wash the ether once with water, then shake
+thoroughly with about fifty cubic centimeters of water, to which from
+<span class="pagenum"><a id="Page_639"></a>[Pg 639]</span>
+six to eight drops of a one-half per cent solution of ferric chlorid
+have been added. Discard the aqueous solution, which contains the
+greater part of the tannin in combination with iron, wash again with
+water, transfer the ethereal solution to a porcelain dish and allow
+to evaporate spontaneously. Heat the dish on the steam bath, take up
+the residue with one or two cubic centimeters of water, filter into
+a test-tube and add one to two drops of one-half per cent solution
+of ferric chlorid. The presence of salicylic acid is indicated by
+the appearance of a violet-red coloration. In the case of red wines,
+a second extraction of the residue with ether mixture is sometimes
+necessary. This method cannot be used in the examination of beers and ales.</p>
+
+<p>(<i>c</i>) <i>Girard’s Method.</i>—Extract a portion of the acidified
+liquor with ether as in the preceding methods, evaporate the extract
+to dryness and exhaust the residue with petroleum ether. The residue
+from the petroleum ether extract is dissolved in water and treated with
+a few drops of a very dilute solution of ferric chlorid. The presence
+of salicylic acid is indicated by the appearance of a violet-red coloration.</p>
+
+<p><b>644. Detection of Gum and Dextrin.</b>—Four cubic centimeters of
+the sample are mixed with ten cubic centimeters of ninety-six per cent
+alcohol. When gum arabic or dextrin is present, a lumpy, thick and
+stringy precipitate is produced, whereas pure wine becomes at first
+opalescent and then gives a flocculent precipitate.</p>
+
+<p><b>645. Determination of Nitrogen.</b>—The best method of determining
+nitrogen in fermented beverages is the common one of moist combustion
+with sulfuric acid. The sample is placed in the kjeldahl digestion
+flask, which is attached to the vacuum service and placed in a
+steam bath until its contents are dry or nearly so. The process is
+then conducted in harmony with the well known methods. Where large
+quantities of the sample are to be employed, as in drinks containing
+but little nitrogen, the preliminary evaporation may be accomplished in
+an open dish, the contents of which are transferred to the digestion
+flask before any solid matter is deposited. The same procedure may be
+followed when the sample foams too much on heating.
+<span class="pagenum"><a id="Page_640"></a>[Pg 640]</span></p>
+
+<p><b>646. Substitutes for Hops.</b>—It is often claimed that cheap and
+deleterious bitters are used in brewing in order to save hops. While
+it is doubtless true that foreign bitters are sometimes employed, the
+experience of this laboratory goes to show that such an adulteration
+is not very prevalent in this country.<a id="FNanchor_650" href="#Footnote_650" class="fnanchor">[650]</a>
+Possibly strychnin, picrotoxin, quassin, gentian and other bitter
+principles have sometimes been found in beer, but their use is no
+longer common. It is difficult to decide in every case whether or not
+foreign bitters have been added. A common process is to treat the
+sample with lead acetate, filter, remove the lead from the filtrate
+and detect any remaining bitters by the taste. All the hop bitters
+are removed by the above process. Any remaining bitter taste is due
+to other substances. For the methods of detecting the special bitter
+principles in hops and other substances, the work of Dragendorff may be
+consulted.<a id="FNanchor_651" href="#Footnote_651" class="fnanchor">[651]</a></p>
+
+<p><b>647. Bouquet of Fermented and Distilled Liquors.</b>—The bouquet
+of fermented and distilled liquors is due to the presence of volatile
+matters which may have three different origins. In the first place the
+materials from which these beverages are made contain essential oils
+and other odoriferous principles.<a id="FNanchor_652" href="#Footnote_652" class="fnanchor">[652]</a>
+In the grape, for instance, the essential oils are found particularly
+in the skins. These essential principles may be secured by distilling
+the skins of grapes in a current of steam. This method of separation,
+however, cannot be regarded as strictly quantitive.</p>
+
+<p>In the second place, the yeasts which produce the alcoholic
+fermentation are also capable of producing odoriferous products.
+These minute vegetations, resembling in their biological relations
+the mushrooms, grow in the soil and reach their maturity at about
+the time of the harvest of the grapes. Their spores are transmitted
+through the air, reach the expressed grape juice and produce the vinous
+fermentation. The particular odor due to any given yeast persists
+through many generations of culture showing that the body which
+produces the odor is the direct result of the vegetable activity of the
+yeast. A beer yeast, after many generations of culture, will still give
+a product which smells like beer, and in like manner a wine yeast will
+produce one which has the odor of wine. The quantity of odorant matter
+<span class="pagenum"><a id="Page_641"></a>[Pg 641]</span>
+produced by this vegetable action is so minute as to escape detection
+in a quantitive or qualitive way by chemical means. These subtle
+perfumes arise moreover not only from the breaking up of the sugar
+molecule, but are also the direct results of molecular synthesis
+accomplished under the influence of the yeast itself.</p>
+
+<p>In the third place, the fermented and distilled liquors contain
+odoriferous principles due to the chemical reactions which take place
+by the breaking up of the sugar and other molecules during the process
+of fermentation. The alcohols and acids produced have distinct odors by
+which they are often recognized. This is particularly true of ethylic,
+propylic, butylic, amylic and oenanthylic alcohols and acetic acid.
+These alcohols themselves also undergo oxidation, passing first into
+the state of aldehyds which, together with ethers, produce the peculiar
+aroma which is found in various fruits. The etherification noted above
+is of course preceded by the formation of acids corresponding to the
+various aldehyds present. The formation of these ethers takes place
+very slowly during aging, and it therefore requires three or four
+years for the proper ripening of wines or distilled liquors. By means
+of artificial heat, electricity and aeration, the oxidizing processes
+above noted may be hastened, but it is doubtful whether the products
+arising from this artificial treatment are as perfect as those which
+are formed in the natural processes.</p>
+
+<h3>AUTHORITIES CITED IN PART SEVENTH.</h3>
+<div class="footnotes">
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_535" href="#FNanchor_535" class="label">[535]</a>
+Bulletin 46, Chemical Division U. S. Department of Agriculture, pp. 24-25.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_536" href="#FNanchor_536" class="label">[536]</a>
+Bulletin 42, Arkansas Agricultural Experiment Station, pp. 81 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_537" href="#FNanchor_537" class="label">[537]</a>
+Balland; Recherches sur les Blés, les Farines et le Pain, p. 229.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_538" href="#FNanchor_538" class="label">[538]</a>
+Jago; Flour and Bread, p. 457.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_539" href="#FNanchor_539" class="label">[539]</a>
+Jago; op. cit. supra, p. 465.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_540" href="#FNanchor_540" class="label">[540]</a>
+Richardson; Journal of the Chemical Society, Transactions,
+1885, pp. 84 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_541" href="#FNanchor_541" class="label">[541]</a>
+Auct. et op. cit. supra, pp. 80 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_542" href="#FNanchor_542" class="label">[542]</a>
+Bulletin 28, Office of Experiment Stations, U. S.
+Department of Agriculture, pp. 9, 10.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_543" href="#FNanchor_543" class="label">[543]</a>
+Bulletin 29, Office of Experiment Stations U. S. Department of Agriculture, p. 8.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_544" href="#FNanchor_544" class="label">[544]</a>
+Op. et. loc. cit. supra.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_545" href="#FNanchor_545" class="label">[545]</a>
+Experiment Station Record, Vol. 6, pp. 590 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_546" href="#FNanchor_546" class="label">[546]</a>
+Annual Report, U. S. Department of Agriculture, 1884, p. 365.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_547" href="#FNanchor_547" class="label">[547]</a>
+Forschungs-Berichte über Lebensmittel, Band 3, S. 142.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_642"></a>[Pg 642]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_548" href="#FNanchor_548" class="label">[548]</a>
+Zeitschrift für angewandte Chemie, 1895, S. 620.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_549" href="#FNanchor_549" class="label">[549]</a>
+Op. et loc. cit. supra.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_550" href="#FNanchor_550" class="label">[550]</a>
+Les Ferments Solubles; Diastases—Enzymes.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_551" href="#FNanchor_551" class="label">[551]</a>
+Wiley; Medical News, July, 1888.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_552" href="#FNanchor_552" class="label">[552]</a>
+Virchow’s Archiv., Band 123, S. 230: Journal of the
+Chemical Society, Abstracts, 1892, p. 755.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_553" href="#FNanchor_553" class="label">[553]</a>
+Ladenberg; Handwörterbuch der Chemie, Band 4, S. 122.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_554" href="#FNanchor_554" class="label">[554]</a>
+Chemisches Centralblatt, 1892, Band 2, S. 579.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_555" href="#FNanchor_555" class="label">[555]</a>
+Op. cit. supra, 1890, Band 2, S. 628.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_556" href="#FNanchor_556" class="label">[556]</a>
+Die Landwirtschaftlichen Versuchs-Stationen, Band 44, S. 188;
+Experiment Station Record, Vol. 6, p. 12.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_557" href="#FNanchor_557" class="label">[557]</a>
+Experiment Station Record, Vol. 6, pp. 5 et seq.
+(Read Jordan instead of Gordon.)</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_558" href="#FNanchor_558" class="label">[558]</a>
+Journal of the American Chemical Society, Vol. 16, pp. 590 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_559" href="#FNanchor_559" class="label">[559]</a>
+From photograph made in this laboratory by Bigelow.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_560" href="#FNanchor_560" class="label">[560]</a>
+Journal of the Society of Chemical Industry, Vol. 10, p. 118.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_561" href="#FNanchor_561" class="label">[561]</a>
+Die Landwirtschaftlichen Versuchs-Stationen, Band 36, S. 321:
+Bulletin 13, Chemical Division, U. S. Department of Agriculture, p. 1028.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_562" href="#FNanchor_562" class="label">[562]</a>
+Wilson; Vid. op. et loc. cit. 26.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_563" href="#FNanchor_563" class="label">[563]</a>
+U. S. Dispensatory, p. 1088.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_564" href="#FNanchor_564" class="label">[564]</a>
+Landwirtschaftliche Jahrbücher, 1890, Band 19, S. 149.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_565" href="#FNanchor_565" class="label">[565]</a>
+Bulletin 13, Chemical Division, U.S. Department of Agriculture, p. 1028.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_566" href="#FNanchor_566" class="label">[566]</a>
+Zeitschrift für analytische Chemie, Band 35, S. 498.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_567" href="#FNanchor_567" class="label">[567]</a>
+Annual Report of the Maine Agricultural Experiment Station, 1891,
+p. 25: Gay; Annales Agronomiques, 1885, p. 145, et 1896, pp. 145 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_568" href="#FNanchor_568" class="label">[568]</a>
+Annales Agronomiques, Tome 21, pp. 149, 150.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_569" href="#FNanchor_569" class="label">[569]</a>
+Vid. op. et loc. cit. primo sub 33.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_570" href="#FNanchor_570" class="label">[570]</a>
+Twelfth Annual Report of the Massachusetts Agricultural Experiment Station,
+1894, p. 175.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_571" href="#FNanchor_571" class="label">[571]</a>
+See also paragraph <b><a href="#P_586">586</a></b> this volume.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_572" href="#FNanchor_572" class="label">[572]</a>
+Manuscript prepared for publication as a part of Bulletin 13,
+Chemical Division, U. S. Department of Agriculture.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_573" href="#FNanchor_573" class="label">[573]</a>
+Vid. this volume, paragraph <b><a href="#P_280">280</a></b>.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_574" href="#FNanchor_574" class="label">[574]</a>
+Vid. op. cit. 31, p. 1020.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_575" href="#FNanchor_575" class="label">[575]</a>
+Bulletin 45, Chemical Division, U.S. Department of Agriculture, p. 12.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_576" href="#FNanchor_576" class="label">[576]</a>
+Berthelot; Essai de Chimie Mécanique: Thomsen; Thermo Chemische
+Untersuchungen: Ostwald; Algemeine Chemie: Muir; Elements of Thermal
+Chemistry.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_577" href="#FNanchor_577" class="label">[577]</a>
+Bulletin 21, Office of Experiment Stations, U. S. Department of
+Agriculture, pp. 113 et seq.: Seventh Annual Report Connecticut
+(Storr’s) Agricultural Experiment Station, pp. 133 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_578" href="#FNanchor_578" class="label">[578]</a>
+Vid. op. et loc. cit. 43.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_579" href="#FNanchor_579" class="label">[579]</a>
+From personal inspection by author in Williams’ laboratory,
+161 Tremont St., Boston, Mass.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_580" href="#FNanchor_580" class="label">[580]</a>
+Journal für praktische Chemie, Band 147 {Neue Folge Band 39},
+Ss. 517 et seq.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_643"></a>[Pg 643]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_581" href="#FNanchor_581" class="label">[581]</a>
+Berthelot; Annales de Chemie et de Physique, 6e Série, Tome 10, p. 439.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_582" href="#FNanchor_582" class="label">[582]</a>
+Vid. op. cit. 46, Ss. 522-523. The data in paragraph <b><a href="#P_566">566</a></b>
+are taken from Stohmann, Zeitschrift für Biologie, Band 31, S. 364 and
+Experiment Station Record, Vol. 6, p. 590.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_583" href="#FNanchor_583" class="label">[583]</a>
+Journal of the American Chemical Society, Vol. 18, p. 174.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_584" href="#FNanchor_584" class="label">[584]</a>
+Bulletins 93, 97, 101 and 102, California Agricultural Experiment Station.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_585" href="#FNanchor_585" class="label">[585]</a>
+Annual Report, U. S. Department of Agriculture, 1886, p. 354.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_586" href="#FNanchor_586" class="label">[586]</a>
+This work, Vol. 2, p. 318.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_587" href="#FNanchor_587" class="label">[587]</a>
+Vid. California Bulletins cited under 50: Wolff; Aschen Analyse, S. 126.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_588" href="#FNanchor_588" class="label">[588]</a>
+Bulletin 100, Cornell Agricultural Experiment Station: Bulletin 48,
+Chemical Division, U. S. Department of Agriculture.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_589" href="#FNanchor_589" class="label">[589]</a>
+Vid. op. cit. 51, p. 353.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_590" href="#FNanchor_590" class="label">[590]</a>
+Vid. op. cit. ultimo sub 54.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_591" href="#FNanchor_591" class="label">[591]</a>
+Bulletin No. 42, Arkansas Agricultural Experiment Station, p. 78.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_592" href="#FNanchor_592" class="label">[592]</a>
+Annual Report, U. S. Department of Agriculture, 1884, p. 347.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_593" href="#FNanchor_593" class="label">[593]</a>
+Spencer; Bulletin 13, U. S. Department of Agriculture, pp. 875 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_594" href="#FNanchor_594" class="label">[594]</a>
+Journal of Analytical and Applied Chemistry, Vol. 4, p. 390; Bulletin
+13, Chemical Division, U. S. Department of Agriculture, p. 889.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_595" href="#FNanchor_595" class="label">[595]</a>
+Pharmaceutical Journal, Vol. 52, p. 213.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_596" href="#FNanchor_596" class="label">[596]</a>
+Commercial Organic Analysis, Vol. 3, part 2, p. 484.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_597" href="#FNanchor_597" class="label">[597]</a>
+Journal de Pharmacie et de Chimie, 6ᵉ Série, Tome 3, p. 529.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_598" href="#FNanchor_598" class="label">[598]</a>
+Journal of the American Chemical Society, Vol. 18, p. 338.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_599" href="#FNanchor_599" class="label">[599]</a>
+Manuscript communication to author.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_600" href="#FNanchor_600" class="label">[600]</a>
+Vid. op. cit. 63, p. 533.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_601" href="#FNanchor_601" class="label">[601]</a>
+American Chemical Journal, Vol. 14, p. 473.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_602" href="#FNanchor_602" class="label">[602]</a>
+Op. et loc. cit. supra.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_603" href="#FNanchor_603" class="label">[603]</a>
+Lindsey; Report made to Thirteenth Annual Convention of the Association
+of Official Agricultural Chemists, Nov. 6th, 1896: Tollens; Handbuch
+der Kohlenhydrate, Band 2, S. 52.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_604" href="#FNanchor_604" class="label">[604]</a>
+Zeitschrift für angewandte Chemie, 1896, p. 195,</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_605" href="#FNanchor_605" class="label">[605]</a>
+Comptes rendus hebdomadaires de Seances de l’Academie des Sciences, Tome 122, p. 841.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_606" href="#FNanchor_606" class="label">[606]</a>
+The Tannins, two volumes.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_607" href="#FNanchor_607" class="label">[607]</a>
+Dragendorff; Plant Analysis.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_608" href="#FNanchor_608" class="label">[608]</a>
+The Tannins, Vol. 1, p. 33.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_609" href="#FNanchor_609" class="label">[609]</a>
+Bulletin 13, Chemical Division, U. S. Department of Agriculture, p. 908.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_610" href="#FNanchor_610" class="label">[610]</a>
+Vid. op. cit. 74, p. 38.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_611" href="#FNanchor_611" class="label">[611]</a>
+Bulletin 46, Chemical Division, U. S. Department of Agriculture, p.
+77 as revised at 13th annual meeting of the Association of Official
+Agricultural Chemists.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_612" href="#FNanchor_612" class="label">[612]</a>
+Vid. op. cit. 75, p. 890: Zeitschrift für analytische Chemie, Band 25,
+S. 121: Journal of the Society of Chemical Industry, Vol. 3, p. 82:
+Trimble; The Tannins, Vol. 1, p. 44.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_613" href="#FNanchor_613" class="label">[613]</a>
+Vid. op. cit. 74, p. 48.</p>
+</div>
+
+<p><span class="pagenum"><a id="Page_644"></a>[Pg 644]</span></p>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_614" href="#FNanchor_614" class="label">[614]</a>
+McElroy; Analyses made in this laboratory.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_615" href="#FNanchor_615" class="label">[615]</a>
+Annual Report Connecticut Agricultural Experiment Station
+(New Haven) 1892, p. 30.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_616" href="#FNanchor_616" class="label">[616]</a>
+Kissling; Tabakkunde, S. 40.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_617" href="#FNanchor_617" class="label">[617]</a>
+Vid. op. cit. supra, S. 58.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_618" href="#FNanchor_618" class="label">[618]</a>
+Vid. op. cit. 81, p. 29.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_619" href="#FNanchor_619" class="label">[619]</a>
+This work, Vol 1, pp. 500 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_620" href="#FNanchor_620" class="label">[620]</a>
+This work, Vol. 1, p. 420.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_621" href="#FNanchor_621" class="label">[621]</a>
+Vid. op. cit. 82, S. 62.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_622" href="#FNanchor_622" class="label">[622]</a>
+Vid. op. cit. supra, S. 64.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_623" href="#FNanchor_623" class="label">[623]</a>
+Dragendorff; Plant Analysis, p. 65.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_624" href="#FNanchor_624" class="label">[624]</a>
+Sugar, 1896, March 15th, p. 11.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_625" href="#FNanchor_625" class="label">[625]</a>
+Vid. op. cit. 82, S. 65.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_626" href="#FNanchor_626" class="label">[626]</a>
+Der Tabak, S. 144.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_627" href="#FNanchor_627" class="label">[627]</a>
+Vid. op. cit. 82, S. 65: Zeitschrift für analytische Chemie, Band 21,
+S. 76: Band 22, S. 199: Band 32, S. 277: Band 34, Ss. 413-731.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_628" href="#FNanchor_628" class="label">[628]</a>
+Zeitschrift für physiologische Chemie  Band 13, S. 445: Band 14, S. 182.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_629" href="#FNanchor_629" class="label">[629]</a>
+Zeitschrift für analytische Chemie, Band 34, S. 413, Band 35, Ss. 309, 731.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_630" href="#FNanchor_630" class="label">[630]</a>
+Annual Report Connecticut Agricultural Experiment Station
+(New Haven), 1892, p. 17.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_631" href="#FNanchor_631" class="label">[631]</a>
+Buell; The Cider-makers’ Manual: Southby; Systematic Text-Book of
+Practical Brewing: Moritz and Morris; Text-Book of the Science of Brewing.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_632" href="#FNanchor_632" class="label">[632]</a>
+Gautier; Sophistication et Analyse des Vins, p. 49.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_633" href="#FNanchor_633" class="label">[633]</a>
+Auct. et. op. cit. supra, p. 44.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_634" href="#FNanchor_634" class="label">[634]</a>
+Bulletin 46, Chemical Division, U. S. Department of Agriculture, p. 63.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_635" href="#FNanchor_635" class="label">[635]</a>
+Manuscript not yet published.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_636" href="#FNanchor_636" class="label">[636]</a>
+Vid. op. cit. 100, pp. 95 et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_637" href="#FNanchor_637" class="label">[637]</a>
+Wiley; Journal of the American Chemical Society, Vol. 18, p. 1063.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_638" href="#FNanchor_638" class="label">[638]</a>
+Vid. op. cit. 100, p. 70.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_639" href="#FNanchor_639" class="label">[639]</a>
+Vid. op. cit. 98, p. 65.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_640" href="#FNanchor_640" class="label">[640]</a>
+Vid. op. cit. 98, p. 67.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_641" href="#FNanchor_641" class="label">[641]</a>
+The Analyst, Vol. 21, p. 158.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_642" href="#FNanchor_642" class="label">[642]</a>
+Vid. op. cit. 98, p. 98.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_643" href="#FNanchor_643" class="label">[643]</a>
+Vid. op. cit. 100, p. 74.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_644" href="#FNanchor_644" class="label">[644]</a>
+Vid. op. cit. 100, p. 75.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_645" href="#FNanchor_645" class="label">[645]</a>
+Vid. op. cit. 100, p. 75.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_646" href="#FNanchor_646" class="label">[646]</a>
+Bulletin de la Société Chimique de Paris, Série {2}, Tome 24, p. 288;
+Berichte der deutschen chemischen Gesellschaft, Band 8, S. 257.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_647" href="#FNanchor_647" class="label">[647]</a>
+Vid. op. cit. 98, p. 120.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_648" href="#FNanchor_648" class="label">[648]</a>
+Bulletin 46, Chemical Division U. S. Department of Agriculture, pp. 72, et. seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_649" href="#FNanchor_649" class="label">[649]</a>
+This work, Vol. 2, pp. 267 and 326.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_650" href="#FNanchor_650" class="label">[650]</a>
+Bulletin 13, Chemical Division, U. S. Department of Agriculture, p. 296.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_651" href="#FNanchor_651" class="label">[651]</a>
+Plant Analysis, pp. 38, et seq.</p>
+</div>
+
+<div class="footnote"><p class="no-indent">
+<a id="Footnote_652" href="#FNanchor_652" class="label">[652]</a>
+Repertoire de Pharmacie, Série 3e, Tome 7, p. 436.</p>
+</div>
+</div>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum"><a id="Page_645"></a>[Pg 645]</span></p>
+<h2 class="nobreak">INDEX.</h2>
+</div>
+
+<ul class="index">
+<li class="isub20 fs_110">Page.</li>
+<li class="isub7 fs_120"><b>A</b></li>
+<li class="isub2">Abbe, refractometer, <a href="#Page_329">329</a></li>
+<li class="isub2">Acetic acid, estimation in tobacco, <a href="#Page_602">602</a></li>
+<li class="isub2">Acetyl value, <a href="#Page_384">384</a>, <a href="#Page_385">385</a></li>
+<li class="isub2">Acidity, estimation in fermented beverages, <a href="#Page_27">27</a></li>
+<li class="isub3">of milk, determination, <a href="#Page_473">473</a></li>
+<li class="isub2">Acids, determination in fruits and vegetables, <a href="#Page_579">579</a></li>
+<li class="isub2">Agricultural products, classification of miscellaneous, <a href="#Page_541">541</a></li>
+<li class="isub3">description, <a href="#Page_1">1</a></li>
+<li class="isub2">Air-bath, drying, <a href="#Page_16">16</a></li>
+<li class="isub2">Albumin, definition, <a href="#Page_410">410</a></li>
+<li class="isub3">gyrodynals of hydrates, <a href="#Page_276">276</a></li>
+<li class="isub3">precipitants in milk, <a href="#Page_276">276</a></li>
+<li class="isub3">qualitive tests, <a href="#Page_420">420</a></li>
+<li class="isub3">separation in milk, <a href="#Page_509">509</a></li>
+<li class="isub2">Albuminates, definition and properties, <a href="#Page_411">411</a></li>
+<li class="isub3">estimation in cheese, <a href="#Page_531">531</a></li>
+<li class="isub3">qualitive tests, <a href="#Page_421">421</a></li>
+<li class="isub2">Albuminoids, <a href="#Page_413">413</a></li>
+<li class="isub3">definition, <a href="#Page_410">410</a></li>
+<li class="isub2">Albumins, action, on polarized light, <a href="#Page_422">422</a></li>
+<li class="isub3">gyrodynats, <a href="#Page_422">422</a></li>
+<li class="isub3">properties, <a href="#Page_410">410</a></li>
+<li class="isub3">separation, <a href="#Page_439">439</a></li>
+<li class="isub2">Albumose peptone, <a href="#Page_461">461</a></li>
+<li class="isub2">Albumoses, estimation, in cheese, <a href="#Page_531">531</a></li>
+<li class="isub3">separation, from peptones, <a href="#Page_455">455</a></li>
+<li class="isub2">Alcohol, calculating, in fermented beverages, <a href="#Page_616">616</a></li>
+<li class="isub3">digestion, <a href="#Page_245">245</a></li>
+<li class="isub3">estimation, by vapor temperature, <a href="#Page_622">622</a></li>
+<li class="isub4">in ensilage, <a href="#Page_546">546</a></li>
+<li class="isub5">fermented beverages, <a href="#Page_612">612</a></li>
+<li class="isub5">koumiss, <a href="#Page_534">534</a></li>
+<li class="isub5">sugar analysis, <a href="#Page_186">186</a></li>
+<li class="isub3">reagent for precipitating dextrin, <a href="#Page_292">292</a></li>
+<li class="isub3">table showing percentage, <a href="#Page_617">617-621</a></li>
+<li class="isub2">Alcoholic digestion, sugar beets, <a href="#Page_248">248-250</a></li>
+<li class="isub2">Alcoholometer, <a href="#Page_612">612</a></li>
+<li class="isub2">Aliphalytic ferments, <a href="#Page_556">556</a></li>
+<li class="isub2">Alkali, action on reducing sugars, <a href="#Page_131">131</a>, <a href="#Page_132">132</a></li>
+<li class="isub2">Alkaline copper solutions, comparison, <a href="#Page_127">127-129</a></li>
+<li class="isub2">Alkaloidal nitrogen, estimation, <a href="#Page_432">432</a></li>
+<li class="isub3">qualitive tests, <a href="#Page_422">422</a>, <a href="#Page_423">423</a></li>
+<li class="isub2">Alkaloids, occurrence, <a href="#Page_417">417</a></li>
+<li class="isub2">Allantoin, <a href="#Page_428">428</a></li>
+<li class="isub2">Allein and Gaud, modification of Pavy’s process, <a href="#Page_145">145</a></li>
+<li class="isub2">Allen, modification of Pavy’s process, <a href="#Page_144">144</a></li>
+<li class="isub3">potassium cyanid process, <a href="#Page_146">146</a></li>
+<li class="isub2">Allihn, gravimetric dextrose method, <a href="#Page_155">155-158</a>
+            <span class="pagenum"><a id="Page_646"></a>[Pg 646]</span></li>
+<li class="isub2">Alum, occurrence, in bread, <a href="#Page_544">544</a></li>
+<li class="isub5">reagent for casein, <a href="#Page_535">535</a></li>
+<li class="isub2">Alumina cream, clarification, <a href="#Page_100">100</a></li>
+<li class="isub2">Aluminum dishes, drying, <a href="#Page_33">33</a></li>
+<li class="isub2">Amagat-Jean, refractometer, <a href="#Page_334">334-338</a></li>
+<li class="isub2">Amid nitrogen, estimation, <a href="#Page_424">424</a></li>
+<li class="isub3">in cereals, <a href="#Page_543">543</a></li>
+<li class="isub4">tobacco, <a href="#Page_607">607</a></li>
+<li class="isub3">occurrence, <a href="#Page_417">417</a></li>
+<li class="isub3">qualitive test, <a href="#Page_418">418</a></li>
+<li class="isub3">separation, in cheese, <a href="#Page_530">530</a></li>
+<li class="isub2">Ammonia, estimation, in tobacco, <a href="#Page_605">605</a></li>
+<li class="isub2">Ammoniacal copper solution, <a href="#Page_143">143</a></li>
+<li class="isub3">nitrogen, estimation, <a href="#Page_423">423</a>, <a href="#Page_424">424</a></li>
+<li class="isub4">in cheese, <a href="#Page_531">531</a></li>
+<li class="isub3">qualitive test, <a href="#Page_419">419</a></li>
+<li class="isub2">Ammonium sulfate, reagent for milk proteids, <a href="#Page_507">507</a></li>
+<li class="isub3">precipitating proteids, <a href="#Page_433">433</a></li>
+<li class="isub2">Amyl alcohol, use, in milk fat analysis, <a href="#Page_501">501</a></li>
+<li class="isub2">Amyliferous bodies, desiccation, <a href="#Page_299">299</a></li>
+<li class="isub2">Amyloid bodies in milk, <a href="#Page_512">512</a></li>
+<li class="isub2">Amylolytic ferments, <a href="#Page_556">556</a></li>
+<li class="isub2">Anatto, <a href="#Page_522">522</a></li>
+<li class="isub2">Animal products, sampling, <a href="#Page_448">448</a></li>
+<li class="isub3">substances, preparation, <a href="#Page_4">4</a>, <a href="#Page_5">5</a></li>
+<li class="isub2">Anoptose, <a href="#Page_234">234</a></li>
+<li class="isub2">Antipeptones, <a href="#Page_412">412</a></li>
+<li class="isub2">Aqueous diffusion, sugar beet analysis, <a href="#Page_251">251</a>, <a href="#Page_252">252</a></li>
+<li class="isub2">Araban, occurrence, <a href="#Page_586">586</a></li>
+<li class="isub2">Arabinose, molecular weight, <a href="#Page_177">177</a></li>
+<li class="isub2">Arachidic acid, separation, <a href="#Page_398">398</a>, <a href="#Page_399">399</a></li>
+<li class="isub2">Areometric method, application in milk fat analysis, <a href="#Page_494">494</a>, <a href="#Page_495">495</a></li>
+<li class="isub2">Areometry, <a href="#Page_70">70</a></li>
+<li class="isub2">Artificial digestion, <a href="#Page_555">555</a></li>
+<li class="isub3">manipulation, <a href="#Page_561">561</a></li>
+<li class="isub3">smoker, <a href="#Page_609">609</a></li>
+<li class="isub2">Ash, composition, in milk, <a href="#Page_466">466</a>, <a href="#Page_467">467</a></li>
+<li class="isub4">of fruit, <a href="#Page_580">580</a></li>
+<li class="isub3">estimation, <a href="#Page_36">36</a></li>
+<li class="isub4">in butter, <a href="#Page_516">516</a></li>
+<li class="isub5">cereals, <a href="#Page_542">542</a></li>
+<li class="isub5">fermented beverages, <a href="#Page_637">637</a></li>
+<li class="isub5">koumiss, <a href="#Page_536">536</a></li>
+<li class="isub5">meats, <a href="#Page_550">550</a></li>
+<li class="isub5">milk, <a href="#Page_482">482</a></li>
+<li class="isub5">proteids, <a href="#Page_444">444</a></li>
+<li class="isub3">German method, <a href="#Page_39">39</a></li>
+<li class="isub2">Asparagin, <a href="#Page_417">417</a></li>
+<li class="isub3">estimation, <a href="#Page_426">426</a>, <a href="#Page_427">427</a></li>
+<li class="isub3">preparation, <a href="#Page_426">426</a></li>
+<li class="isub2">Aspartic acid, <a href="#Page_412">412</a></li>
+<li class="isub2">Atwater and Woods, calorimeter, <a href="#Page_569">569</a></li>
+<li class="isub3">methods of meat analysis, <a href="#Page_549">549</a></li>
+<li class="isub3">preparation of fish, <a href="#Page_12">12</a></li>
+<li class="isub2">Auric chlorid, color test with fats and oils, <a href="#Page_356">356</a></li>
+<li class="isub2">Authorities cited in Part</li>
+<li class="isub3">Fifth, <a href="#Page_462">462</a>, <a href="#Page_463">463</a></li>
+<li class="isub3">First, <a href="#Page_56">56</a>, <a href="#Page_57">57</a>
+               <span class="pagenum"><a id="Page_647"></a>[Pg 647]</span></li>
+<li class="isub3">Fourth, <a href="#Page_406">406-409</a></li>
+<li class="isub3">Second, <a href="#Page_222">222</a></li>
+<li class="isub3">Seventh, <a href="#Page_641">641-644</a></li>
+<li class="isub3">Sixth, <a href="#Page_536">536-540</a></li>
+<li class="isub3">Third, <a href="#Page_306">306-308</a></li>
+
+<li class="isub7 ifrst fs_120"><b>B</b></li>
+<li class="isub2">Babcock, formula, for calculating total solids, <a href="#Page_479">479</a>, <a href="#Page_480">480</a></li>
+<li class="isub3">method of counting fat globules, <a href="#Page_483">483</a>, <a href="#Page_484">484</a></li>
+<li class="isub4">milk fat analysis, <a href="#Page_499">499</a>, <a href="#Page_500">500</a></li>
+<li class="isub2">Bacteria, reactions, on sugar, <a href="#Page_196">196</a></li>
+<li class="isub2">Bagasse, analysis, <a href="#Page_239">239</a>, <a href="#Page_240">240</a></li>
+<li class="isub2">Barfoed, reagent, for removing dextrose, <a href="#Page_291">291</a>, <a href="#Page_292">292</a></li>
+<li class="isub2">Barium saccharate, <a href="#Page_187">187</a></li>
+<li class="isub2">Barley starch, <a href="#Page_221">221</a></li>
+<li class="isub2">Basic lead acetate, clarification, <a href="#Page_101">101</a></li>
+<li class="isub2">Baumé and brix degrees, comparison, <a href="#Page_73">73</a></li>
+<li class="isub2">Bean starch, <a href="#Page_220">220</a></li>
+<li class="isub2">Bechi’s test for cottonseed oil, <a href="#Page_400">400</a>, <a href="#Page_401">401</a></li>
+<li class="isub2">Beet rasp, <a href="#Page_10">10</a>, <a href="#Page_251">251</a></li>
+<li class="isub2">Beimling, method of milk fat analysis, <a href="#Page_502">502</a></li>
+<li class="isub2">Betain, <a href="#Page_417">417</a></li>
+<li class="isub3">separation from cholin, <a href="#Page_429">429</a></li>
+<li class="isub2">Bigelow and McElroy, estimation of sugar in evaporated milks, <a href="#Page_296">296-298</a></li>
+<li class="isub3">method of dialysis, <a href="#Page_447">447</a></li>
+<li class="isub3">table for correcting hydrostatic plummet, <a href="#Page_615">615</a></li>
+<li class="isub2">Biliverdin, occurrence in milk, <a href="#Page_464">464</a></li>
+<li class="isub2">Birotation, <a href="#Page_118">118</a></li>
+<li class="isub3">mathematical theory, <a href="#Page_177">177</a>, <a href="#Page_178">178</a></li>
+<li class="isub2">Biuret reaction, <a href="#Page_419">419</a></li>
+<li class="isub2">Block, feculometer, <a href="#Page_300">300</a></li>
+<li class="isub2">Bone-black, decolorization, <a href="#Page_104">104</a></li>
+<li class="isub2">Bordeaux-red, determination, in wines, <a href="#Page_637">637</a></li>
+<li class="isub2">Bouquet of fermented and distilled liquors, <a href="#Page_640">640</a>, <a href="#Page_641">641</a></li>
+<li class="isub2">Bread, acidity, <a href="#Page_544">544</a></li>
+<li class="isub3">amount of water, <a href="#Page_544">544</a></li>
+<li class="isub3">baking, temperature, <a href="#Page_543">543</a></li>
+<li class="isub3">chemical changes in baking, <a href="#Page_545">545</a></li>
+<li class="isub3">color, <a href="#Page_544">544</a></li>
+<li class="isub3">methods of analysis, <a href="#Page_543">543-545</a></li>
+<li class="isub3">nitrogenous compounds, <a href="#Page_544">544</a></li>
+<li class="isub3">soluble extract, <a href="#Page_543">543</a></li>
+<li class="isub2">Brix and baumé degrees, comparison, <a href="#Page_73">73</a></li>
+<li class="isub2">Bromin addition number, <a href="#Page_371">371-373</a></li>
+<li class="isub2">Brullé, color test for fats and oils, <a href="#Page_355">355</a></li>
+<li class="isub2">Butter, adulterants, <a href="#Page_521">521</a></li>
+<li class="isub3">appearance of melted, <a href="#Page_513">513</a></li>
+<li class="isub4">with polarized light, <a href="#Page_514">514</a></li>
+<li class="isub3">calorimetric distinction, from oleomargarin, <a href="#Page_576">576</a></li>
+<li class="isub3">colors, <a href="#Page_522">522</a></li>
+<li class="isub4">detection, <a href="#Page_523">523</a></li>
+<li class="isub3">fat analysis, classification of methods, <a href="#Page_484">484</a></li>
+<li class="isub4">estimation, <a href="#Page_482">482-504</a></li>
+<li class="isub3">methods of analysis, <a href="#Page_512">512-523</a></li>
+<li class="isub3">microscopic examination, <a href="#Page_513">513</a></li>
+<li class="isub3">molecular weight, <a href="#Page_520">520</a>
+                <span class="pagenum"><a id="Page_648"></a>[Pg 648]</span></li>
+<li class="isub3">refractive index, <a href="#Page_514">514</a></li>
+<li class="isub3">relative proportion of ingredients, <a href="#Page_517">517</a></li>
+<li class="isub3">substitutes, molecular weight, <a href="#Page_520">520</a>, <a href="#Page_521">521</a></li>
+<li class="isub2">Butyrin, <a href="#Page_310">310</a></li>
+<li class="isub2">Butyrorefractometer, <a href="#Page_339">339-341</a></li>
+<li class="isub3">range of application, <a href="#Page_342">342</a></li>
+
+<li class="isub7 ifrst fs_120"><b>C</b></li>
+<li class="isub2">Caffein, estimation, <a href="#Page_583">583</a></li>
+<li class="isub2">Caffetannic acid, <a href="#Page_590">590</a></li>
+<li class="isub2">Calcium saccharates, <a href="#Page_188">188</a></li>
+<li class="isub2">Caldwell, hydrogen drying oven, <a href="#Page_26">26</a>, <a href="#Page_27">27</a></li>
+<li class="isub2">Calories, computation, <a href="#Page_574">574-578</a></li>
+<li class="isub3">definition, <a href="#Page_576">576</a></li>
+<li class="isub2">Calorimeter, description, <a href="#Page_569">569</a></li>
+<li class="isub3">formulas for calculation, <a href="#Page_572">572</a></li>
+<li class="isub3">hydrothermal value, <a href="#Page_573">573</a></li>
+<li class="isub3">manipulation, <a href="#Page_571">571</a></li>
+<li class="isub2">Calorimetric equivalents, <a href="#Page_576">576</a></li>
+<li class="isub2">Calorimetry, <a href="#Page_568">568-576</a></li>
+<li class="isub2">Canada balsam, mounting starches, <a href="#Page_219">219</a></li>
+<li class="isub2">Cane cutting machines, <a href="#Page_236">236</a>, <a href="#Page_237">237</a></li>
+<li class="isub3">pulp, determination of sugar, <a href="#Page_238">238</a></li>
+<li class="isub4">drying and extraction, <a href="#Page_238">238</a></li>
+<li class="isub3">sugar, gyrodynat, <a href="#Page_117">117</a>, <a href="#Page_118">118</a></li>
+<li class="isub2">Carbohydrates, <a href="#Page_58">58</a></li>
+<li class="isub3">estimation in cereals, <a href="#Page_543">543</a></li>
+<li class="isub3">kind, <a href="#Page_58">58</a></li>
+<li class="isub3">milk, <a href="#Page_511">511</a></li>
+<li class="isub3">molecular weights, <a href="#Page_175">175</a></li>
+<li class="isub3">nomenclature, <a href="#Page_59">59</a></li>
+<li class="isub3">occurrence, <a href="#Page_58">58</a></li>
+<li class="isub4">in coffee, <a href="#Page_585">585</a></li>
+<li class="isub4">of rare, <a href="#Page_306">306</a></li>
+<li class="isub3">separation, <a href="#Page_279">279</a></li>
+<li class="isub4">in fruits and vegetables, <a href="#Page_577">577</a></li>
+<li class="isub2">Carbon, estimation in proteids, <a href="#Page_444">444</a></li>
+<li class="isub3">dioxid, determination, in sugar analysis, <a href="#Page_186">186</a></li>
+<li class="isub4">estimation, in koumiss, <a href="#Page_532">532</a></li>
+<li class="isub4">reagent for casein, <a href="#Page_509">509</a></li>
+<li class="isub3">tetrachlorid, reagent in iodin addition, <a href="#Page_368">368</a></li>
+<li class="isub2">Carnin, <a href="#Page_416">416</a></li>
+<li class="isub3">composition, <a href="#Page_451">451</a></li>
+<li class="isub2">Carr, vacuum drying oven, <a href="#Page_22">22</a>, <a href="#Page_23">23</a></li>
+<li class="isub2">Casein, estimation, in butter, <a href="#Page_516">516</a></li>
+<li class="isub4">cheese, <a href="#Page_531">531</a></li>
+<li class="isub4">with mercurial salts, <a href="#Page_535">535</a></li>
+<li class="isub3">factors for calculating, <a href="#Page_508">508</a></li>
+<li class="isub3">method of estimating, <a href="#Page_508">508</a></li>
+<li class="isub3">precipitants in milk, <a href="#Page_276">276</a></li>
+<li class="isub3">precipitation, by alum, <a href="#Page_535">535</a></li>
+<li class="isub3">preparation, <a href="#Page_509">509</a></li>
+<li class="isub3">separation, by filtering through porous porcelain, <a href="#Page_534">534</a></li>
+<li class="isub4">from albumin, <a href="#Page_507">507</a></li>
+<li class="isub3">solution, in acid, <a href="#Page_489">489</a></li>
+<li class="isub3">theory of precipitation, <a href="#Page_508">508</a></li>
+<li class="isub2">Caseinogen, <a href="#Page_504">504</a>
+             <span class="pagenum"><a id="Page_649"></a>[Pg 649]</span></li>
+<li class="isub2">Cassava starch, <a href="#Page_222">222</a></li>
+<li class="isub2">Cattle foods, <a href="#Page_545">545</a></li>
+<li class="isub2">Cellulose, constitution, <a href="#Page_303">303</a></li>
+<li class="isub3">qualitive reactions, <a href="#Page_306">306</a></li>
+<li class="isub3">separation, <a href="#Page_304">304</a></li>
+<li class="isub3">solubility, <a href="#Page_305">305</a></li>
+<li class="isub2">Cereals, general principles of analysis, <a href="#Page_542">542</a></li>
+<li class="isub2">Chalmot and Tollens, method of estimating pentosans, <a href="#Page_182">182</a></li>
+<li class="isub2">Chandler and Ricketts, polariscope, <a href="#Page_266">266</a></li>
+<li class="isub2">Cheese, artificial digestion, <a href="#Page_561">561</a></li>
+<li class="isub3">composition, <a href="#Page_524">524</a></li>
+<li class="isub3">constituents, <a href="#Page_530">530</a></li>
+<li class="isub3">filled, <a href="#Page_529">529</a></li>
+<li class="isub3">methods of analysis, <a href="#Page_526">526-533</a></li>
+<li class="isub3">manufacture, <a href="#Page_525">525</a></li>
+<li class="isub3">proteids, separation, <a href="#Page_530">530</a>, <a href="#Page_531">531</a></li>
+<li class="isub2">Chitin, <a href="#Page_416">416</a></li>
+<li class="isub3">character of reaction, <a href="#Page_512">512</a></li>
+<li class="isub2">Chlorophyll, separation, from caffein, <a href="#Page_585">585</a></li>
+<li class="isub2">Cholesterin, detection, <a href="#Page_403">403</a>, <a href="#Page_404">404</a></li>
+<li class="isub3">occurrence, in milk, <a href="#Page_464">464</a></li>
+<li class="isub2">Cholin, <a href="#Page_417">417</a></li>
+<li class="isub3">separation, from cottonseed, <a href="#Page_428">428</a>, <a href="#Page_429">429</a></li>
+<li class="isub2">Chondrin, <a href="#Page_415">415</a></li>
+<li class="isub2">Chrome yellow, <a href="#Page_522">522</a></li>
+<li class="isub2">Chrysolite, use, in drying, <a href="#Page_486">486</a></li>
+<li class="isub2">Chyle, occurrence, in milk, <a href="#Page_464">464</a></li>
+<li class="isub2">Chyme, occurrence, in milk, <a href="#Page_464">464</a></li>
+<li class="isub2">Citric acid, estimation, in tobacco, <a href="#Page_601">601</a></li>
+<li class="isub3">occurrence, in milk, <a href="#Page_466">466</a></li>
+<li class="isub2">Clerget, method of inversion, <a href="#Page_105">105-107</a></li>
+<li class="isub2">Cobaltous nitrate, reagent for nitrate, <a href="#Page_189">189</a></li>
+<li class="isub2">Collagen, <a href="#Page_413">413</a></li>
+<li class="isub2">Coloring matters, determination, in wines, <a href="#Page_636">636</a>, <a href="#Page_637">637</a></li>
+<li class="isub2">Combustion products, <a href="#Page_36">36</a>, <a href="#Page_37">37</a></li>
+<li class="isub2">Conchiolin, <a href="#Page_416">416</a></li>
+<li class="isub2">Conglutin, <a href="#Page_411">411</a></li>
+<li class="isub2">Constant monochromatic flame, <a href="#Page_85">85</a></li>
+<li class="isub2">Control observation tube, <a href="#Page_95">95</a>, <a href="#Page_96">96</a></li>
+<li class="isub2">Copper carbonate process, <a href="#Page_138">138-140</a></li>
+<li class="isub4">use, in estimating sucrose, dextrose and levulose, <a href="#Page_282">282</a>, <a href="#Page_283">283</a></li>
+<li class="isub3">cyanid, reagent for estimating lactose, <a href="#Page_294">294</a>, <a href="#Page_295">295</a></li>
+<li class="isub3">oxid, weighing, in sugar analysis, <a href="#Page_262">262</a></li>
+<li class="isub3">reagent in determining oxygen absorption of oils, <a href="#Page_405">405</a></li>
+<li class="isub3">salts, reduction, by sugar, <a href="#Page_123">123</a></li>
+<li class="isub3">solution, action on dextrose, <a href="#Page_125">125</a></li>
+<li class="isub3">sulfate, reagent for milk proteids, <a href="#Page_506">506</a></li>
+<li class="isub4">separating proteid from amid nitrogen, <a href="#Page_433">433</a></li>
+<li class="isub3">titration of residual, <a href="#Page_148">148</a>, <a href="#Page_149">149</a></li>
+<li class="isub2">Cottonseed oil, detection, <a href="#Page_400">400</a></li>
+<li class="isub2">Courtonne, ash muffle, <a href="#Page_40">40</a></li>
+<li class="isub2">Crampton, preparation of fat crystals, <a href="#Page_347">347</a></li>
+<li class="isub2">Creamometry, <a href="#Page_474">474</a></li>
+<li class="isub2">Creydt, formula, <a href="#Page_110">110</a></li>
+<li class="isub2">Crismer, critical temperature, <a href="#Page_349">349</a>, <a href="#Page_350">350</a></li>
+<li class="isub2">Critical temperature, fats and oils, <a href="#Page_349">349</a></li>
+<li class="isub2">Crude proteids, estimation, in cereals, <a href="#Page_543">543</a>
+                <span class="pagenum"><a id="Page_650"></a>[Pg 650]</span></li>
+<li class="isub2">Crystallin, <a href="#Page_411">411</a></li>
+<li class="isub2">Crystallization, temperature, <a href="#Page_327">327</a></li>
+<li class="isub2">Cuprous oxid, specific gravity, <a href="#Page_137">137</a></li>
+<li class="isub2">Curd, estimation, in butter, <a href="#Page_516">516</a></li>
+
+<li class="isub7 ifrst fs_120"><b>D</b></li>
+<li class="isub2">Dairy products, importance, <a href="#Page_464">464</a></li>
+<li class="isub2">Davis, meat preservatives, <a href="#Page_566">566</a></li>
+<li class="isub2">Density, determination, <a href="#Page_63">63</a></li>
+<li class="isub3">of sour milk, <a href="#Page_477">477</a></li>
+<li class="isub2">Deuteroalbumose, <a href="#Page_412">412</a></li>
+<li class="isub2">Dextrin, detection, in fermented beverages, <a href="#Page_639">639</a></li>
+<li class="isub3">occurrence, in glucose, <a href="#Page_264">264</a></li>
+<li class="isub3">precipitation, by alcohol, <a href="#Page_292">292</a></li>
+<li class="isub3">separation, from dextrose and maltose, <a href="#Page_287">287-293</a></li>
+<li class="isub2">Dextrinoid bodies in milk, <a href="#Page_511">511</a></li>
+<li class="isub2">Dextrosazone, <a href="#Page_193">193</a></li>
+<li class="isub2">Dextrose, action of alkaline copper solution, <a href="#Page_125">125</a></li>
+<li class="isub3">estimation, in presence of sucrose, <a href="#Page_274">274</a>, <a href="#Page_275">275</a></li>
+<li class="isub4">and levulose, <a href="#Page_280">280-285</a></li>
+<li class="isub3">group, qualitive test, <a href="#Page_190">190</a></li>
+<li class="isub3">gyrodynat, <a href="#Page_118">118</a></li>
+<li class="isub3">molecular weight, <a href="#Page_176">176</a></li>
+<li class="isub3">removal, by copper acetate, <a href="#Page_291">291</a></li>
+<li class="isub3">separation from maltose and dextrin, <a href="#Page_287">287-293</a></li>
+<li class="isub3">table for calculating, from copper, <a href="#Page_260">260</a></li>
+<li class="isub2">Dialysis, <a href="#Page_447">447</a></li>
+<li class="isub3">application, for precipitating milk proteids, <a href="#Page_511">511</a></li>
+<li class="isub2">Diastase, action, on starch, <a href="#Page_198">198</a></li>
+<li class="isub3">preparation, <a href="#Page_300">300</a></li>
+<li class="isub2">Diffusion, instantaneous, <a href="#Page_243">243</a></li>
+<li class="isub2">Digestion, alcoholic, <a href="#Page_245">245</a></li>
+<li class="isub2">Distillation, methods, <a href="#Page_612">612</a>, <a href="#Page_613">613</a></li>
+<li class="isub2">Doolittle, viscosimeter, <a href="#Page_343">343</a>, <a href="#Page_344">344</a></li>
+<li class="isub2">Double dilution, milk analysis, <a href="#Page_278">278</a></li>
+<li class="isub3">polarization, <a href="#Page_102">102</a></li>
+<li class="isub2">Dreef grinding machine, <a href="#Page_11">11</a></li>
+<li class="isub2">Dry substance, estimation, for factory control, <a href="#Page_263">263</a></li>
+<li class="isub2">Drying samples, general principles, <a href="#Page_34">34</a>, <a href="#Page_35">35</a></li>
+
+<li class="isub7 ifrst fs_120"><b>E</b></li>
+<li class="isub2">Earth bases, reagents for precipitating sugar, <a href="#Page_187">187</a></li>
+<li class="isub2">Ebullioscope, <a href="#Page_622">622</a>, <a href="#Page_623">623</a></li>
+<li class="isub2">Edson, preserving sugar juices, <a href="#Page_235">235</a></li>
+<li class="isub2">Elaidin, <a href="#Page_406">406</a></li>
+<li class="isub2">Elastin, <a href="#Page_415">415</a></li>
+<li class="isub2">Electric drying oven, <a href="#Page_19">19</a></li>
+<li class="isub2">Ensilage, alcohol, <a href="#Page_546">546</a></li>
+<li class="isub3">changes, due to fermentation, <a href="#Page_546">546</a></li>
+<li class="isub3">comparative value, <a href="#Page_547">547</a></li>
+<li class="isub3">organic acids, <a href="#Page_546">546</a></li>
+<li class="isub2">Ether extract, estimation, in cereals, <a href="#Page_542">542</a></li>
+<li class="isub3">solvent, <a href="#Page_41">41</a></li>
+<li class="isub2">Evaporated fruits, <a href="#Page_580">580</a></li>
+<li class="isub3">milk, estimation of sugar, <a href="#Page_296">296</a></li>
+<li class="isub2">Ewell, method of estimating coffee carbohydrates, <a href="#Page_585">585</a>
+            <span class="pagenum"><a id="Page_651"></a>[Pg 651]</span></li>
+<li class="isub3">permanganate method, <a href="#Page_136">136</a></li>
+<li class="isub2">Excreta, collection, <a href="#Page_562">562</a>, <a href="#Page_563">563</a></li>
+<li class="isub2">Extract, composition, in fermented beverages, <a href="#Page_624">624</a></li>
+<li class="isub3">estimation, by indirect method, <a href="#Page_625">625</a></li>
+<li class="isub4">in fermented beverages, <a href="#Page_624">624</a></li>
+<li class="isub4">vacuum, <a href="#Page_626">626</a></li>
+<li class="isub2">Extraction apparatus, <a href="#Page_43">43-51</a></li>
+<li class="isub3">by digestion, <a href="#Page_42">42</a></li>
+<li class="isub4">percolation, <a href="#Page_43">43</a></li>
+<li class="isub3">compact apparatus, <a href="#Page_48">48-51</a></li>
+<li class="isub3">methods, <a href="#Page_41">41</a>, <a href="#Page_42">42</a></li>
+<li class="isub3">with alcohol, <a href="#Page_245">245</a></li>
+
+<li class="isub7 ifrst fs_120"><b>F</b></li>
+<li class="isub2">Fat acids, determinations of nature, <a href="#Page_396">396</a></li>
+<li class="isub4">formulas for calculating yield, <a href="#Page_392">392</a>, <a href="#Page_393">393</a></li>
+<li class="isub4">temperature of crystallization, <a href="#Page_327">327</a></li>
+<li class="isub3">crystals, appearance, with polarized light, <a href="#Page_347">347</a></li>
+<li class="isub4">microscopic appearance, <a href="#Page_346">346</a>, <a href="#Page_347">347</a></li>
+<li class="isub3">estimation, in altered milk, <a href="#Page_487">487</a>, <a href="#Page_488">488</a></li>
+<li class="isub4">butter, <a href="#Page_515">515</a></li>
+<li class="isub4">koumiss, <a href="#Page_534">534</a></li>
+<li class="isub4">meats, <a href="#Page_550">550</a></li>
+<li class="isub4">preserved meats, <a href="#Page_563">563</a></li>
+<li class="isub3">extraction, methods, adapted to milk, <a href="#Page_486">486</a></li>
+<li class="isub3">form of globules in milk, <a href="#Page_482">482</a></li>
+<li class="isub3">globules, method of counting, <a href="#Page_483">483</a></li>
+<li class="isub4">number, in milk, <a href="#Page_482">482</a></li>
+<li class="isub3">in milk, classification of methods of analysis, <a href="#Page_484">484</a></li>
+<li class="isub4">comparison of methods of analysis, <a href="#Page_488">488</a></li>
+<li class="isub4">wet extraction methods, <a href="#Page_488">488</a></li>
+<li class="isub2">Fats and oils, coloration, produced by oxidants, <a href="#Page_352">352</a></li>
+<li class="isub4">consistence, <a href="#Page_396">396</a></li>
+<li class="isub4">drying, for analysis, <a href="#Page_316">316</a></li>
+<li class="isub4">estimation of water, <a href="#Page_317">317</a></li>
+<li class="isub4">extraction, <a href="#Page_41">41</a></li>
+<li class="isub4">melting point, <a href="#Page_320">320-323</a></li>
+<li class="isub4">microscopic appearance, <a href="#Page_345">345</a></li>
+<li class="isub4">physical properties, <a href="#Page_317">317-345</a></li>
+<li class="isub4">polarization, <a href="#Page_350">350</a></li>
+<li class="isub4">preparation, for microscope, <a href="#Page_345">345</a>, <a href="#Page_346">346</a></li>
+<li class="isub4">refractive index, <a href="#Page_328">328</a></li>
+<li class="isub4">sampling, <a href="#Page_315">315</a></li>
+<li class="isub4">solubility, in alcohol, <a href="#Page_351">351</a></li>
+<li class="isub4">specific gravity, <a href="#Page_317">317-319</a></li>
+<li class="isub4">table of densities, <a href="#Page_320">320</a></li>
+<li class="isub4">temperature of crystallization, <a href="#Page_327">327</a></li>
+<li class="isub4">thermal reactions, <a href="#Page_356">356-363</a></li>
+<li class="isub4">turbidity temperature, <a href="#Page_351">351</a></li>
+<li class="isub3">composition, <a href="#Page_309">309</a>, <a href="#Page_310">310</a></li>
+<li class="isub3">freeing, of moisture, <a href="#Page_315">315</a></li>
+<li class="isub3">nomenclature, <a href="#Page_309">309</a></li>
+<li class="isub2">Feculometer, Block, <a href="#Page_300">300</a></li>
+<li class="isub2">Fehling solutions, comparison, <a href="#Page_127">127</a></li>
+<li class="isub3">composition, <a href="#Page_126">126</a></li>
+<li class="isub3">historical, <a href="#Page_124">124</a></li>
+<li class="isub2">Fermentation, method of separating sugars, <a href="#Page_288">288</a>, <a href="#Page_289">289</a>
+                 <span class="pagenum"><a id="Page_652"></a>[Pg 652]</span></li>
+<li class="isub3">use, in sugar analysis, <a href="#Page_185">185</a></li>
+<li class="isub2">Fermented beverages, constituents, <a href="#Page_611">611</a></li>
+<li class="isub3">description, <a href="#Page_610">610</a></li>
+<li class="isub3">distillation, <a href="#Page_612">612-614</a></li>
+<li class="isub3">polarization, <a href="#Page_632">632</a></li>
+<li class="isub3">specific gravity, <a href="#Page_611">611</a></li>
+<li class="isub2">Ferments, aliphalytic, <a href="#Page_556">556</a></li>
+<li class="isub3">amylolytic, <a href="#Page_556">556</a></li>
+<li class="isub3">proteolytic, <a href="#Page_557">557</a></li>
+<li class="isub2">Fiber, estimation, <a href="#Page_303">303</a>, <a href="#Page_304">304</a></li>
+<li class="isub3">in canes, <a href="#Page_241">241</a></li>
+<li class="isub4">cereals, <a href="#Page_543">543</a></li>
+<li class="isub3">occurrence, <a href="#Page_303">303</a></li>
+<li class="isub2">Fibrin, <a href="#Page_413">413</a>, <a href="#Page_504">504</a></li>
+<li class="isub2">Fibrinogen, <a href="#Page_411">411</a></li>
+<li class="isub2">Fibroin, <a href="#Page_416">416</a></li>
+<li class="isub2">Field of vision, appearance, <a href="#Page_81">81</a></li>
+<li class="isub2">Filled cheese, <a href="#Page_529">529</a></li>
+<li class="isub2">Fischer, carbohydrates, <a href="#Page_59">59</a></li>
+<li class="isub2">Fish, preparation, <a href="#Page_12">12</a></li>
+<li class="isub2">Flesh bases, treatment of residue, insoluble in alcohol, <a href="#Page_460">460</a></li>
+<li class="isub2">Foods, constituents, comparative values, <a href="#Page_567">567</a></li>
+<li class="isub3">fuel value, <a href="#Page_551">551</a></li>
+<li class="isub3">nutritive values, <a href="#Page_566">566</a></li>
+<li class="isub3">potential energy, <a href="#Page_551">551</a></li>
+<li class="isub2">Free fat acid, determination, <a href="#Page_394">394</a></li>
+<li class="isub2">Fruits, composition, <a href="#Page_579">579</a></li>
+<li class="isub3">evaporated, <a href="#Page_580">580</a></li>
+<li class="isub3">sampling, <a href="#Page_577">577</a></li>
+<li class="isub2">Fuchsin, detection, in wines, <a href="#Page_637">637</a></li>
+<li class="isub2">Furfurol, determination, <a href="#Page_180">180</a></li>
+<li class="isub3">precipitation, with pyrogalol, <a href="#Page_183">183</a></li>
+<li class="isub3">qualitive tests, for sugars, <a href="#Page_194">194</a></li>
+<li class="isub3">reactions, <a href="#Page_194">194</a>, <a href="#Page_195">195</a></li>
+
+<li class="isub7 ifrst fs_120"><b>G</b></li>
+<li class="isub2">Galactan, method of estimating, <a href="#Page_586">586</a></li>
+<li class="isub3">occurrence, <a href="#Page_586">586</a></li>
+<li class="isub2">Galactosazone, <a href="#Page_193">193</a></li>
+<li class="isub2">Galactose, products of oxidation, with nitric acid, <a href="#Page_191">191</a></li>
+<li class="isub2">Gelatin, <a href="#Page_414">414</a></li>
+<li class="isub3">estimation, <a href="#Page_456">456-459</a></li>
+<li class="isub3">reagent for tannins, <a href="#Page_590">590</a></li>
+<li class="isub2">Gerber, butyrometer, <a href="#Page_502">502</a></li>
+<li class="isub3">method of milk fat analysis, <a href="#Page_502">502-503</a></li>
+<li class="isub2">Gerrard, potassium cyanid process, <a href="#Page_146">146</a></li>
+<li class="isub2">Ginger starch, <a href="#Page_220">220</a></li>
+<li class="isub2">Gird, gravimeter, <a href="#Page_233">233</a></li>
+<li class="isub2">Glacial acetic acid, reagent for fats and oils, <a href="#Page_351">351</a></li>
+<li class="isub2">Gladding, method of preparing fats for the microscope, <a href="#Page_346">346</a></li>
+<li class="isub2">Glass, errors due to poor, <a href="#Page_520">520</a></li>
+<li class="isub2">Gliadin, <a href="#Page_436">436</a></li>
+<li class="isub2">Globin, <a href="#Page_411">411</a></li>
+<li class="isub2">Globulin, separation in milk, <a href="#Page_510">510</a></li>
+<li class="isub2">Globulins, properties, <a href="#Page_411">411</a></li>
+<li class="isub3">separation, <a href="#Page_440">440</a>
+                <span class="pagenum"><a id="Page_653"></a>[Pg 653]</span></li>
+<li class="isub2">Glucosazone, <a href="#Page_171">171</a></li>
+<li class="isub2">Glucose, commercial, <a href="#Page_286">286</a></li>
+<li class="isub3">process of manufacture, <a href="#Page_287">287</a></li>
+<li class="isub2">Glutamic acid, <a href="#Page_412">412</a></li>
+<li class="isub2">Glutamin, <a href="#Page_417">417</a></li>
+<li class="isub3">estimation, <a href="#Page_426">426</a>, <a href="#Page_427">427</a></li>
+<li class="isub2">Gluten, <a href="#Page_413">413</a></li>
+<li class="isub3">composition, <a href="#Page_426">426</a></li>
+<li class="isub3">separation, from wheat flour, <a href="#Page_434">434</a>, <a href="#Page_435">435</a></li>
+<li class="isub2">Glutenin, <a href="#Page_436">436</a></li>
+<li class="isub2">Glutin, <a href="#Page_413">413</a></li>
+<li class="isub3">composition, <a href="#Page_451">451</a></li>
+<li class="isub2">Glycerids, principal, <a href="#Page_310">310</a></li>
+<li class="isub3">saponification value, <a href="#Page_383">383</a>, <a href="#Page_384">384</a></li>
+<li class="isub3">separation, <a href="#Page_397">397</a></li>
+<li class="isub2">Glycerol, estimation, in fermented beverages, <a href="#Page_635">635</a>, <a href="#Page_636">636</a></li>
+<li class="isub3">formulas for calculating yield, <a href="#Page_392">392</a>, <a href="#Page_393">393</a></li>
+<li class="isub2">Gomberg, method of estimating caffein, <a href="#Page_584">584</a>, <a href="#Page_585">585</a></li>
+<li class="isub2">Grape sugar, birotation, <a href="#Page_287">287</a></li>
+<li class="isub3">commercial, <a href="#Page_264">264</a>, <a href="#Page_286">286</a></li>
+<li class="isub2">Gravimeter, <a href="#Page_233">233</a></li>
+<li class="isub2">Green samples, grinding, <a href="#Page_9">9</a></li>
+<li class="isub2">Grinding apparatus, <a href="#Page_6">6-11</a></li>
+<li class="isub2">Gum, detection, in fermented beverages, <a href="#Page_639">639</a></li>
+<li class="isub2">Gypsum, use, in drying sour milk, <a href="#Page_487">487</a></li>
+<li class="isub2">Gyrodynat, definition, <a href="#Page_116">116</a></li>
+
+<li class="isub7 ifrst fs_120"><b>H</b></li>
+<li class="isub2">Haemocyanin, <a href="#Page_411">411</a></li>
+<li class="isub2">Haemoglobin, <a href="#Page_411">411</a></li>
+<li class="isub2">Halle drying apparatus, <a href="#Page_29">29</a></li>
+<li class="isub2">Haloid absorption by fat acids, <a href="#Page_374">374-376</a></li>
+<li class="isub3">addition numbers, <a href="#Page_364">364</a></li>
+<li class="isub2">Heat of bromination, improved method of determining, <a href="#Page_361">361-363</a></li>
+<li class="isub2">Hehner and Mitchell, method of determining heat of bromination, <a href="#Page_361">361</a></li>
+<li class="isub4">Richmond, formula for calculating total solids, <a href="#Page_479">479</a>, <a href="#Page_480">480</a></li>
+<li class="isub4">bromin addition number, <a href="#Page_373">373</a></li>
+<li class="isub2">Hemi-peptones, <a href="#Page_412">412</a></li>
+<li class="isub2">Hempel, calorimeter, <a href="#Page_569">569</a></li>
+<li class="isub2">Heteroalbumose, <a href="#Page_412">412</a></li>
+<li class="isub2">Hibbard, estimation of starch, <a href="#Page_207">207</a></li>
+<li class="isub2">Hide powder, reagent for tannins, <a href="#Page_590">590</a></li>
+<li class="isub3">testing, <a href="#Page_592">592</a></li>
+<li class="isub2">Honey, composition, <a href="#Page_264">264</a></li>
+<li class="isub2">Hoppe-Seyler, cellulose, separation, <a href="#Page_304">304</a></li>
+<li class="isub2">Hops, bitter principles, <a href="#Page_640">640</a></li>
+<li class="isub3">substitutes, <a href="#Page_640">640</a></li>
+<li class="isub2">Horse flesh, detection, <a href="#Page_554">554</a></li>
+<li class="isub2">Hübl’s process, <a href="#Page_364">364-367</a></li>
+<li class="isub3">reagent, preservation, <a href="#Page_371">371</a></li>
+<li class="isub2">Hyalin, <a href="#Page_416">416</a></li>
+<li class="isub2">Hyalogen, <a href="#Page_416">416</a></li>
+<li class="isub2">Hydrochloric acid, estimation, in tobacco, <a href="#Page_600">600</a></li>
+<li class="isub2">Hydrogen, drying, <a href="#Page_24">24</a></li>
+<li class="isub3">estimation, in proteids, <a href="#Page_444">444</a></li>
+<li class="isub2">Hydrometer, balling, <a href="#Page_71">71</a></li>
+<li class="isub3">baumé, <a href="#Page_71">71</a>
+              <span class="pagenum"><a id="Page_654"></a>[Pg 654]</span></li>
+<li class="isub3">brix, <a href="#Page_71">71</a></li>
+<li class="isub2">Hydrometers, <a href="#Page_71">71</a></li>
+<li class="isub2">Hydrometry, correction for temperature, <a href="#Page_72">72</a></li>
+<li class="isub2">Hydrostatic balance, <a href="#Page_68">68</a></li>
+<li class="isub3">plummet, <a href="#Page_615">615</a></li>
+<li class="isub4">correction table, <a href="#Page_615">615</a></li>
+<li class="isub2">Hypogaeic acid, separation, <a href="#Page_399">399</a></li>
+<li class="isub2">Hypoxanthin, occurrence, in milk, <a href="#Page_464">464</a></li>
+
+<li class="isub7 ifrst fs_120"><b>I</b></li>
+<li class="isub2">Impurities, error due, <a href="#Page_74">74</a></li>
+<li class="isub2">Incineration, purpose and conduct, <a href="#Page_37">37</a>, <a href="#Page_38">38</a></li>
+<li class="isub2">Insoluble fat acids, determination, <a href="#Page_391">391</a>, <a href="#Page_392">392</a></li>
+<li class="isub2">Inversion, application of the process, <a href="#Page_114">114</a></li>
+<li class="isub3">calculation of results, <a href="#Page_108">108</a>, <a href="#Page_109">109</a></li>
+<li class="isub3">determination of sucrose, <a href="#Page_105">105</a></li>
+<li class="isub3">influence of strength of solution, <a href="#Page_108">108</a></li>
+<li class="isub4">time of heating, <a href="#Page_108">108</a></li>
+<li class="isub2">Invert sugar, estimation of minute quantities, <a href="#Page_257">257</a></li>
+<li class="isub3">gyrodynat, <a href="#Page_119">119</a></li>
+<li class="isub3">influence of temperature on gyrodynat, <a href="#Page_265">265</a></li>
+<li class="isub3">occurrence, <a href="#Page_264">264</a></li>
+<li class="isub3">official method, <a href="#Page_161">161-162</a></li>
+<li class="isub3">optical neutrality, <a href="#Page_265">265</a></li>
+<li class="isub3">separation and estimation, <a href="#Page_264">264</a></li>
+<li class="isub3">table for calculating, from copper, <a href="#Page_260">260</a></li>
+<li class="isub4">estimating, <a href="#Page_159">159</a>, <a href="#Page_258">258</a></li>
+<li class="isub2">Invertase, determination of activity, <a href="#Page_111">111</a>, <a href="#Page_112">112</a></li>
+<li class="isub3">use, in inversion, <a href="#Page_110">110</a>, <a href="#Page_111">111</a></li>
+<li class="isub2">Invertose, molecular weight, <a href="#Page_177">177</a></li>
+<li class="isub2">Iodin addition, <a href="#Page_364">364-367</a></li>
+<li class="isub4">character of chemical reaction, <a href="#Page_367">367</a></li>
+<li class="isub3">monochlorid, substitution for hübl reagent, <a href="#Page_370">370</a></li>
+<li class="isub3">number, estimation, <a href="#Page_369">369-370</a></li>
+<li class="isub3">reaction with starch, <a href="#Page_196">196</a></li>
+<li class="isub3">reagent for caffein, <a href="#Page_584">584</a></li>
+
+<li class="isub7 ifrst fs_120"><b>J</b></li>
+<li class="isub2">Juices, analysis of fruit and vegetable, <a href="#Page_578">578</a></li>
+
+<li class="isub7 ifrst fs_120"><b>K</b></li>
+<li class="isub2">Keratin, <a href="#Page_416">416</a></li>
+<li class="isub2">Kieselguhr, use in drying, <a href="#Page_486">486</a></li>
+<li class="isub2">Knorr, extraction apparatus, <a href="#Page_44">44</a></li>
+<li class="isub3">fractional analysis of meats, <a href="#Page_552">552</a></li>
+<li class="isub2">Koettstorfer, saponification value, <a href="#Page_382">382</a>, <a href="#Page_383">383</a></li>
+<li class="isub2">Koumiss, acidity, <a href="#Page_532">532</a></li>
+<li class="isub3">composition, <a href="#Page_532">532</a>, <a href="#Page_536">536</a></li>
+<li class="isub2">Kreatin, <a href="#Page_416">416</a></li>
+<li class="isub3">composition, <a href="#Page_431">431</a></li>
+<li class="isub3">determination, <a href="#Page_454">454</a></li>
+<li class="isub3">occurrence in milk, <a href="#Page_464">464</a></li>
+<li class="isub2">Kreatinin, <a href="#Page_416">416</a></li>
+<li class="isub3">composition, <a href="#Page_451">451</a></li>
+<li class="isub3">determination, <a href="#Page_454">454</a></li>
+<li class="isub2">Krug, method of determining oxygen absorption of oils, <a href="#Page_405">405</a>, <a href="#Page_406">406</a></li>
+<li class="isub4">estimating pentosans, <a href="#Page_179">179</a>, <a href="#Page_183">183</a></li>
+<li class="isub3">separation of oleic and hypogaeic acids, <a href="#Page_399">399</a></li>
+<li class="isub3">viscosity of oils, <a href="#Page_345">345</a>
+             <span class="pagenum"><a id="Page_655"></a>[Pg 655]</span></li>
+<li class="isub7 ifrst fs_120"><b>L</b></li>
+<li class="isub2">Lactobutyrometer, <a href="#Page_495">495</a>, <a href="#Page_496">496</a></li>
+<li class="isub2">Lactocrite, use in milk fat analysis, <a href="#Page_498">498</a></li>
+<li class="isub2">Lactoglobulin, <a href="#Page_504">504</a></li>
+<li class="isub2">Lactometer, direct reading, <a href="#Page_476">476</a></li>
+<li class="isub3">New York Board of Health, <a href="#Page_476">476</a></li>
+<li class="isub2">Lactometry, <a href="#Page_475">475</a>, <a href="#Page_476">476</a></li>
+<li class="isub2">Lactoprotein, <a href="#Page_504">504</a></li>
+<li class="isub2">Lactosazone, precipitation, <a href="#Page_295">295</a></li>
+<li class="isub2">Lactoscopes, <a href="#Page_473">473</a>, <a href="#Page_474">474</a></li>
+<li class="isub2">Lactose, estimation, <a href="#Page_293">293</a></li>
+<li class="isub4">in Koumiss, <a href="#Page_534">534</a></li>
+<li class="isub5">milk, <a href="#Page_275">275</a></li>
+<li class="isub3">gyrodynat, <a href="#Page_119">119</a></li>
+<li class="isub3">molecular weight, <a href="#Page_177">177</a></li>
+<li class="isub3">official method of estimation, <a href="#Page_294">294</a></li>
+<li class="isub2">Laurent lamp, <a href="#Page_83">83</a>, <a href="#Page_84">84</a></li>
+<li class="isub3">polariscope, <a href="#Page_83">83</a></li>
+<li class="isub4">construction, <a href="#Page_86">86-88</a></li>
+<li class="isub4">manipulation, <a href="#Page_88">88</a></li>
+<li class="isub2">Lead acetate, preserving agent, <a href="#Page_235">235</a></li>
+<li class="isub3">oxid, separation of sugars, <a href="#Page_284">284</a>, <a href="#Page_285">285</a></li>
+<li class="isub3">reagent for determining oxygen absorption of oils, <a href="#Page_405">405</a></li>
+<li class="isub3">salts, reagents for separating fat acids, <a href="#Page_397">397</a></li>
+<li class="isub3">solutions, errors, <a href="#Page_102">102</a></li>
+<li class="isub3">subacetate, action on levulose, <a href="#Page_103">103</a></li>
+<li class="isub2">Lecithin, extraction from seeds, <a href="#Page_430">430</a>, <a href="#Page_431">431</a></li>
+<li class="isub3">factors for calculating, <a href="#Page_431">431</a></li>
+<li class="isub3">occurrence and properties, <a href="#Page_430">430</a></li>
+<li class="isub4">in milk, <a href="#Page_464">464</a></li>
+<li class="isub2">Leffmann and Beam, method of milk fat analysis, <a href="#Page_501">501</a></li>
+<li class="isub2">Legumin, <a href="#Page_411">411</a></li>
+<li class="isub2">Leucin, <a href="#Page_412">412</a></li>
+<li class="isub3">occurrence in milk, <a href="#Page_464">464</a></li>
+<li class="isub2">Levulosazone, <a href="#Page_193">193</a></li>
+<li class="isub2">Levulose, estimation, <a href="#Page_168">168</a></li>
+<li class="isub4">in presence of sucrose and dextrose, <a href="#Page_280">280-285</a></li>
+<li class="isub3">general formula for calculation, <a href="#Page_274">274</a></li>
+<li class="isub3">gyrodynat, <a href="#Page_119">119</a></li>
+<li class="isub3">optical determination, <a href="#Page_267">267</a></li>
+<li class="isub3">preparation, <a href="#Page_167">167</a></li>
+<li class="isub3">principles of calculation, <a href="#Page_270">270-273</a></li>
+<li class="isub3">table for calculating from copper, <a href="#Page_260">260</a></li>
+<li class="isub3">estimation, <a href="#Page_169">169-171</a></li>
+<li class="isub2">Liebermann, method of milk fat analysis, <a href="#Page_471">471</a>, <a href="#Page_492">492</a></li>
+<li class="isub2">Liebig ente, <a href="#Page_28">28</a></li>
+<li class="isub2">Light, kind used for polarization, <a href="#Page_82">82</a></li>
+<li class="isub2">Lindet, method of inversion, <a href="#Page_109">109</a>, <a href="#Page_110">110</a></li>
+<li class="isub2">Lindsey and Holland, digestibility of pentosans, <a href="#Page_564">564</a></li>
+<li class="isub2">Lindström, modification of lactocrite, <a href="#Page_499">499</a></li>
+<li class="isub2">Lineolin, <a href="#Page_310">310</a></li>
+<li class="isub2">Lint, use, in drying, <a href="#Page_486">486</a></li>
+<li class="isub2">Livache, method of determining oxygen absorption, <a href="#Page_405">405</a></li>
+<li class="isub2">Long and Baker, diastase preparation, <a href="#Page_300">300</a>
+          <span class="pagenum"><a id="Page_656"></a>[Pg 656]</span></li>
+<li class="isub3">table of refractive indices, <a href="#Page_334">334</a></li>
+
+<li class="isub7 ifrst fs_120"><b>Mc</b></li>
+<li class="isub2">McElroy and Bigelow, estimation of sugar in</li>
+<li class="isub5">evaporated milks, <a href="#Page_296">296-298</a></li>
+<li class="isub3">estimation of nicotin, <a href="#Page_605">605</a></li>
+<li class="isub2">McIlhiney, bromin addition number, <a href="#Page_372">372</a></li>
+
+<li class="isub7 ifrst fs_120"><b>M</b></li>
+<li class="isub2">Maercker, apparatus for hydrolysis of starch, <a href="#Page_204">204</a></li>
+<li class="isub3">method of sugar analysis, <a href="#Page_153">153-155</a></li>
+<li class="isub2">Magnesium sulfate, reagent for precipitating proteids, <a href="#Page_433">433</a></li>
+<li class="isub2">Maize starch, <a href="#Page_221">221</a></li>
+<li class="isub2">Malic acid, estimation in fermented beverages, <a href="#Page_630">630</a>, <a href="#Page_631">631</a></li>
+<li class="isub3">tobacco, <a href="#Page_601">601</a></li>
+<li class="isub2">Malt extract, <a href="#Page_301">301</a></li>
+<li class="isub2">Maltosazone, <a href="#Page_193">193</a></li>
+<li class="isub2">Maltose, estimation, <a href="#Page_165">165</a></li>
+<li class="isub3">gyrodynat, <a href="#Page_119">119</a>, <a href="#Page_206">206</a></li>
+<li class="isub3">molecular weight, <a href="#Page_177">177</a></li>
+<li class="isub3">occurrence, in glucose, <a href="#Page_264">264</a></li>
+<li class="isub3">separation from dextrin and dextrose, <a href="#Page_287">287-293</a></li>
+<li class="isub3">table for calculating from copper, <a href="#Page_261">261</a></li>
+<li class="isub4">determination, <a href="#Page_165">165-167</a></li>
+<li class="isub2">Maple sugar, <a href="#Page_228">228</a></li>
+<li class="isub3">conditions of manufacture, <a href="#Page_228">228</a></li>
+<li class="isub2">Maranta starch, <a href="#Page_219">219</a></li>
+<li class="isub2">Massecuites, analysis, <a href="#Page_254">254</a></li>
+<li class="isub3">determination of ash, <a href="#Page_256">256</a></li>
+<li class="isub4">reducing sugars, <a href="#Page_256">256</a></li>
+<li class="isub4">water, <a href="#Page_255">255</a></li>
+<li class="isub2">Maumené, heat of sulfuric saponification, <a href="#Page_357">357</a>, <a href="#Page_358">358</a></li>
+<li class="isub2">Maxwell, method of extracting lecithin, <a href="#Page_430">430</a>, <a href="#Page_431">431</a></li>
+<li class="isub2">Meat extracts, analysis, <a href="#Page_452">452-454</a></li>
+<li class="isub3">composition, <a href="#Page_451">451</a>, <a href="#Page_452">452</a></li>
+<li class="isub2">Meats, estimation of proteids, <a href="#Page_550">550</a></li>
+<li class="isub3">fractional analysis, <a href="#Page_552">552</a></li>
+<li class="isub3">methods of analysis, <a href="#Page_549">549-554</a></li>
+<li class="isub3">sampling, <a href="#Page_547">547</a></li>
+<li class="isub3">scientific names,<a href="#Page_547">547</a></li>
+<li class="isub2">Meissl, table for invert sugar, <a href="#Page_158">158</a></li>
+<li class="isub2">Melons, sampling, <a href="#Page_577">577</a></li>
+<li class="isub2">Melting point, determination by spheroidal state, <a href="#Page_323">323-326</a></li>
+<li class="isub3">methods of determining, <a href="#Page_321">321-326</a></li>
+<li class="isub3">of fats and oils, <a href="#Page_320">320-323</a></li>
+<li class="isub2">Mercuric compounds, clarification, <a href="#Page_104">104</a></li>
+<li class="isub3">cyanid, reagent for destroying reducing sugars, <a href="#Page_290">290</a>, <a href="#Page_291">291</a></li>
+<li class="isub3">salts, reagent for casein, <a href="#Page_535">535</a></li>
+<li class="isub4">reduction by sugar, <a href="#Page_121">121</a></li>
+<li class="isub2">Metabolism, vegetable and animal, <a href="#Page_2">2</a></li>
+<li class="isub2">Metalbumin, <a href="#Page_415">415</a></li>
+<li class="isub2">Methyl blue, qualitive test for invert sugar, <a href="#Page_192">192</a></li>
+<li class="isub2">Micro-organisms, occurrence in milk, <a href="#Page_469">469</a></li>
+<li class="isub2">Midzu ame, Japan glucose, <a href="#Page_286">286</a></li>
+<li class="isub3">composition, <a href="#Page_264">264</a></li>
+<li class="isub2">Milk, acidity, <a href="#Page_475">475</a></li>
+<li class="isub3">alkalinity, <a href="#Page_472">472</a></li>
+<li class="isub3">alterabitity, <a href="#Page_467">467</a>, <a href="#Page_468">468</a>
+         <span class="pagenum"><a id="Page_657"></a>[Pg 657]</span></li>
+<li class="isub3">appearance, <a href="#Page_469">469</a></li>
+<li class="isub3">carbohydrates, <a href="#Page_293">293</a>, <a href="#Page_511">511</a></li>
+<li class="isub3">composition, <a href="#Page_464">464</a>, <a href="#Page_465">465</a>, <a href="#Page_468">468</a></li>
+<li class="isub3">determination of total solids, <a href="#Page_477">477</a></li>
+<li class="isub3">effects of boiling, <a href="#Page_469">469</a></li>
+<li class="isub3">electric conductivity, <a href="#Page_472">472</a></li>
+<li class="isub3">error due to volume of precipitate in polarization, <a href="#Page_277">277</a></li>
+<li class="isub3">fat analysis, volumetric methods, <a href="#Page_496">496-504</a></li>
+<li class="isub4">extraction, asbestos process, <a href="#Page_485">485</a></li>
+<li class="isub5">paper coil method, <a href="#Page_485">485</a></li>
+<li class="isub5">variation of methods, <a href="#Page_486">486</a></li>
+<li class="isub3">freezing point, <a href="#Page_472">472</a></li>
+<li class="isub3">mean composition, <a href="#Page_465">465</a></li>
+<li class="isub3">opacity, <a href="#Page_473">473</a></li>
+<li class="isub3">polarization, <a href="#Page_277">277</a></li>
+<li class="isub3">preservatives, <a href="#Page_471">471</a>, <a href="#Page_472">472</a></li>
+<li class="isub3">proteids, <a href="#Page_504">504</a></li>
+<li class="isub4">estimation, <a href="#Page_505">505</a></li>
+<li class="isub4">precipitants, <a href="#Page_510">510</a></li>
+<li class="isub3">sampling, <a href="#Page_469">469</a>, <a href="#Page_470">470</a></li>
+<li class="isub3">serum, density, <a href="#Page_477">477</a></li>
+<li class="isub3">specific gravity, <a href="#Page_474">474</a></li>
+<li class="isub3">sterilized, <a href="#Page_468">468</a></li>
+<li class="isub3">sugar, estimation, <a href="#Page_163">163</a>, <a href="#Page_164">164</a></li>
+<li class="isub4">table for estimation, <a href="#Page_163">163</a></li>
+<li class="isub3">viscosity, <a href="#Page_472">472</a></li>
+<li class="isub2">Millian, method for determining solubility, <a href="#Page_351">351</a></li>
+<li class="isub3">modification of Bechi’s test, <a href="#Page_401">401</a></li>
+<li class="isub3">process of separating arachidic acid, <a href="#Page_398">398</a></li>
+<li class="isub2">Million’s reagent, <a href="#Page_421">421</a></li>
+<li class="isub2">Mills, grinding, <a href="#Page_7">7-11</a></li>
+<li class="isub2">Mitscherlich, determination of ash, <a href="#Page_83">83</a></li>
+<li class="isub4">reducing sugars, <a href="#Page_256">256</a></li>
+<li class="isub4">water, <a href="#Page_255">255</a></li>
+<li class="isub3">specific gravity, <a href="#Page_254">254</a>, <a href="#Page_255">255</a></li>
+<li class="isub2">Monochromatic flame, constant, <a href="#Page_85">85</a></li>
+<li class="isub2">Mother beets, determination of sugar, <a href="#Page_250">250</a>, <a href="#Page_251">251</a></li>
+<li class="isub2">Mucic acid, test for lactose, <a href="#Page_190">190</a></li>
+<li class="isub2">Mucin, <a href="#Page_414">414</a></li>
+<li class="isub2">Munroe, thermal reactions of oils, <a href="#Page_359">359</a></li>
+<li class="isub2">Muscular tissues, occurrence in meat extracts, <a href="#Page_456">456</a></li>
+<li class="isub3">separation of nitrogenous bodies, <a href="#Page_448">448-450</a></li>
+<li class="isub2">Muskmelons, composition, <a href="#Page_581">581</a>, <a href="#Page_582">582</a></li>
+<li class="isub2">Muter, method of determining haloid addition, <a href="#Page_374">374-376</a></li>
+<li class="isub3">process of separating fat acids, <a href="#Page_397">397</a></li>
+<li class="isub3">table, for identifying starches, <a href="#Page_214">214-217</a></li>
+<li class="isub2">Mycsin, <a href="#Page_411">411</a></li>
+<li class="isub2">Myrosin, <a href="#Page_411">411</a></li>
+
+<li class="isub7 ifrst fs_120"><b>N</b></li>
+<li class="isub2">Natural digestion, <a href="#Page_562">562</a></li>
+<li class="isub2">Neuclein, <a href="#Page_415">415</a></li>
+<li class="isub2">Neucleoproteids, <a href="#Page_415">415</a></li>
+<li class="isub2">Neurokeratin, <a href="#Page_416">416</a></li>
+<li class="isub2">Nickel prism, <a href="#Page_77">77</a></li>
+<li class="isub3">theory, <a href="#Page_77">77-80</a>
+           <span class="pagenum"><a id="Page_658"></a>[Pg 658]</span></li>
+<li class="isub2">Nicotin, estimation in tobacco, <a href="#Page_605">605-607</a></li>
+<li class="isub3">gyrodynat, <a href="#Page_606">606</a></li>
+<li class="isub3">polarization, <a href="#Page_606">606</a></li>
+<li class="isub2">Nitric acid, color test, fats and oils, <a href="#Page_353">353</a></li>
+<li class="isub3">estimation in tobacco, <a href="#Page_600">600</a></li>
+<li class="isub3">qualitive test, <a href="#Page_418">418</a></li>
+<li class="isub2">Nitrogen, estimation in fermented beverages, <a href="#Page_639">639</a></li>
+<li class="isub5">flesh bases, <a href="#Page_459">459</a></li>
+<li class="isub5">proteids, <a href="#Page_445">445</a></li>
+<li class="isub4">of total, <a href="#Page_423">423</a></li>
+<li class="isub3">percentage in proteids, <a href="#Page_445">445</a></li>
+<li class="isub2">Nitrogenous bases, occurrence in animal tissues, <a href="#Page_450">450</a>, <a href="#Page_451">451</a></li>
+<li class="isub3">bodies, composition, <a href="#Page_410">410</a></li>
+<li class="isub4">estimation in meats, <a href="#Page_551">551</a></li>
+<li class="isub4">occurrence in animal products, <a href="#Page_448">448-462</a></li>
+<li class="isub4">qualitive tests, <a href="#Page_418">418-421</a></li>
+<li class="isub4">separation in cheese, <a href="#Page_530">530</a></li>
+<li class="isub2">Nutritive ratio, <a href="#Page_568">568</a></li>
+<li class="isub3">values, <a href="#Page_566">566</a></li>
+
+<li class="isub7 ifrst fs_120"><b>O</b></li>
+<li class="isub2">Oat starch, <a href="#Page_221">221</a></li>
+<li class="isub2">Observation tube, continuous, <a href="#Page_253">253</a></li>
+<li class="isub2">Oil press, <a href="#Page_312">312</a></li>
+<li class="isub3">removal from starchy bodies, <a href="#Page_300">300</a></li>
+<li class="isub2">Oils and fats, extraction, <a href="#Page_310">310</a>, <a href="#Page_314">314</a></li>
+<li class="isub4">identification, <a href="#Page_395">395</a>, <a href="#Page_406">406</a></li>
+<li class="isub4">physical properties, <a href="#Page_317">317</a>, <a href="#Page_345">345</a></li>
+<li class="isub3">coefficient of expansion, <a href="#Page_319">319</a></li>
+<li class="isub3">composition, <a href="#Page_309">309</a>, <a href="#Page_310">310</a></li>
+<li class="isub3">heat of bromination, <a href="#Page_360">360</a></li>
+<li class="isub3">nomenclature, <a href="#Page_309">309</a></li>
+<li class="isub3">spectroscopic examination, <a href="#Page_348">348</a></li>
+<li class="isub2">Oleic acid separation from palmitic, <a href="#Page_397">397</a></li>
+<li class="isub2">Olein, <a href="#Page_310">310</a></li>
+<li class="isub2">Oleomargarin, calometric distinction from butter, <a href="#Page_576">576</a></li>
+<li class="isub2">Oleorefractometer, <a href="#Page_334">334</a></li>
+<li class="isub2">Oleothermometer, <a href="#Page_514">514</a></li>
+<li class="isub2">Organic acids, occurrence in ensilage, <a href="#Page_546">546</a></li>
+<li class="isub2">Orseille, detection in wines, <a href="#Page_637">637</a></li>
+<li class="isub2">Osazones, melting points, <a href="#Page_193">193</a></li>
+<li class="isub2">Ost, copper carbonate method, <a href="#Page_258">258</a>, <a href="#Page_259">259</a></li>
+<li class="isub3">solution, <a href="#Page_257">257</a></li>
+<li class="isub2">Oven, electric, <a href="#Page_19">19</a></li>
+<li class="isub3">hydrogen drying, <a href="#Page_25">25</a>, <a href="#Page_27">27</a></li>
+<li class="isub3">steam coil, <a href="#Page_20">20</a>, <a href="#Page_21">21</a></li>
+<li class="isub3">water jacket, drying, <a href="#Page_14">14</a></li>
+<li class="isub2">Oxalic acid, estimation in tobacco, <a href="#Page_601">601</a></li>
+<li class="isub2">Oxygen, absorption by oils, <a href="#Page_405">405</a></li>
+<li class="isub3">combustion, <a href="#Page_569">569</a></li>
+
+<li class="isub7 ifrst fs_120"><b>P</b></li>
+<li class="isub2">Palm sugar, <a href="#Page_228">228</a></li>
+<li class="isub2">Palmitic acid, separation from oleic, <a href="#Page_397">397</a></li>
+<li class="isub2">Palmitin, <a href="#Page_310">310</a></li>
+<li class="isub2">Pancreas extract, digestion, <a href="#Page_560">560</a>
+           <span class="pagenum"><a id="Page_659"></a>[Pg 659]</span></li>
+<li class="isub3">peptone, <a href="#Page_461">461</a></li>
+<li class="isub2">Pancreatin digestion, <a href="#Page_558">558</a></li>
+<li class="isub3">preparation, <a href="#Page_560">560</a></li>
+<li class="isub2">Paraffin, occurrence in plants, <a href="#Page_404">404</a>, <a href="#Page_405">405</a></li>
+<li class="isub2">Paralbumin, <a href="#Page_415">415</a></li>
+<li class="isub2">Patrick, volumetric method of milk fat analysis, <a href="#Page_497">497</a></li>
+<li class="isub2">Pavy’s process, <a href="#Page_143">143</a></li>
+<li class="isub2">Pea starch, <a href="#Page_220">220</a></li>
+<li class="isub2">Peanut oil, detection, <a href="#Page_400">400</a></li>
+<li class="isub2">Pectic acid, estimation in tobacco, <a href="#Page_603">603</a></li>
+<li class="isub2">Pectin, occurrence, <a href="#Page_577">577</a>, <a href="#Page_578">578</a></li>
+<li class="isub3">separation, <a href="#Page_578">578</a></li>
+<li class="isub2">Pectose, occurrence, <a href="#Page_577">577</a></li>
+<li class="isub2">Pellet, continuous observation tube, <a href="#Page_253">253</a></li>
+<li class="isub3">method of cold diffusion, <a href="#Page_243">243</a>, <a href="#Page_244">244</a></li>
+<li class="isub2">Pentosans, digestibility, <a href="#Page_564">564</a></li>
+<li class="isub3">estimation, <a href="#Page_178">178</a></li>
+<li class="isub3">revised factors for calculating, <a href="#Page_587">587</a></li>
+<li class="isub2">Pentose sugars, estimation, <a href="#Page_177">177</a></li>
+<li class="isub2">Pepsin digestion, <a href="#Page_558">558</a></li>
+<li class="isub3">preparation, <a href="#Page_558">558</a></li>
+<li class="isub2">Peptones, <a href="#Page_412">412</a></li>
+<li class="isub3">qualitive tests, <a href="#Page_420">420</a>, <a href="#Page_421">421</a></li>
+<li class="isub3">separation from albumoses, <a href="#Page_455">455</a></li>
+<li class="isub4">in cheese, <a href="#Page_531">531</a></li>
+<li class="isub2">Permanganate gelatin, method for tannins, <a href="#Page_593">593</a>, <a href="#Page_594">594</a></li>
+<li class="isub3">hide powder method for tannins, <a href="#Page_595">595</a></li>
+<li class="isub3">process, <a href="#Page_132">132</a></li>
+<li class="isub4">modified by Ewell, <a href="#Page_136">136</a></li>
+<li class="isub2">Peska’s process, <a href="#Page_144">144</a></li>
+<li class="isub2">Petroleum ether, preparation, <a href="#Page_312">312</a></li>
+<li class="isub4">removal from extracted oils, <a href="#Page_314">314</a></li>
+<li class="isub4">solvent, <a href="#Page_41">41</a></li>
+<li class="isub2">Phenylhydrazin, action on sugars, <a href="#Page_172">172</a>, <a href="#Page_174">174</a></li>
+<li class="isub3">compounds with sugar, <a href="#Page_192">192</a></li>
+<li class="isub3">reagent for precipitating furfurol, <a href="#Page_180">180</a></li>
+<li class="isub4">sugar, <a href="#Page_171">171</a></li>
+<li class="isub2">Phloroglucin, modification of furfurol method, <a href="#Page_588">588</a></li>
+<li class="isub3">reagent for precipitating furfurol, <a href="#Page_184">184</a></li>
+<li class="isub2">Phosphomolybdic acid, color test, fats and oils, <a href="#Page_353">353</a></li>
+<li class="isub2">Phosphorus, loss of organic in combustion, <a href="#Page_37">37</a></li>
+<li class="isub2">Phosphotungstic acid, preparation of reagent, <a href="#Page_454">454</a></li>
+<li class="isub2">Phytalbumoses, <a href="#Page_412">412</a></li>
+<li class="isub2">Phytosterin, detection, <a href="#Page_403">403</a>, <a href="#Page_404">404</a></li>
+<li class="isub2">Picric acid, color test, with fats and oils, <a href="#Page_355">355</a></li>
+<li class="isub2">Plasmin, <a href="#Page_411">411</a></li>
+<li class="isub2">Plaster of paris, use in drying, <a href="#Page_486">486</a></li>
+<li class="isub2">Polarimeter, <a href="#Page_83">83</a></li>
+<li class="isub2">Polarimètre, <a href="#Page_83">83</a></li>
+<li class="isub2">Polarimetry, general principles, <a href="#Page_92">92</a>, <a href="#Page_93">93</a></li>
+<li class="isub2">Polariscope, adjustment, <a href="#Page_93">93</a>, <a href="#Page_94">94</a></li>
+<li class="isub4">of quartz plates, <a href="#Page_96">96</a>, <a href="#Page_97">97</a></li>
+<li class="isub3">definition, <a href="#Page_80">80</a></li>
+<li class="isub3">for estimating levulose, <a href="#Page_267">267</a>, <a href="#Page_270">270</a></li>
+<li class="isub3">kinds, <a href="#Page_80">80</a>, <a href="#Page_81">81</a></li>
+<li class="isub3">rotation instruments, <a href="#Page_82">82</a>
+           <span class="pagenum"><a id="Page_660"></a>[Pg 660]</span></li>
+<li class="isub2">Polaristrobometer, <a href="#Page_83">83</a></li>
+<li class="isub2">Polarization, analytical use of data in</li>
+<li class="isub7">fermented beverages, <a href="#Page_634">634</a>, <a href="#Page_635">635</a></li>
+<li class="isub3">for factory control, <a href="#Page_263">263</a></li>
+<li class="isub3">of fermented beverages, <a href="#Page_632">632</a>, <a href="#Page_633">633</a></li>
+<li class="isub2">Polarized light, <a href="#Page_75">75</a>, <a href="#Page_76">76</a></li>
+<li class="isub3">application to butter analysis, <a href="#Page_514">514</a></li>
+<li class="isub3">relation to sugar analysis, <a href="#Page_74">74</a></li>
+<li class="isub2">Politis, method of sugar analysis, <a href="#Page_148">148</a></li>
+<li class="isub2">Ponceau-red, detection in wines, <a href="#Page_637">637</a></li>
+<li class="isub2">Potash, estimation in wines, <a href="#Page_637">637</a></li>
+<li class="isub2">Potassium cyanid, use in sugar analysis, <a href="#Page_146">146</a></li>
+<li class="isub3">hydroxid, solvent for proteids, <a href="#Page_443">443</a></li>
+<li class="isub3">nitrate, occurrence in maize stalks, <a href="#Page_417">417</a></li>
+<li class="isub4">preserving agent, <a href="#Page_417">417</a></li>
+<li class="isub3">permanganate, reagent for tannins, <a href="#Page_593">593</a></li>
+<li class="isub2">Potato starch, <a href="#Page_220">220</a></li>
+<li class="isub2">Potatoes, estimation of starch, <a href="#Page_301">301</a>, <a href="#Page_302">302</a></li>
+<li class="isub2">Powdered glass, use in drying, <a href="#Page_486">486</a></li>
+<li class="isub2">Preserved meats, <a href="#Page_563">563</a></li>
+<li class="isub2">Proteid bodies, separation, <a href="#Page_432">432</a>, <a href="#Page_448">448</a></li>
+<li class="isub3">nitrogen, estimation in tea and coffee, <a href="#Page_585">585</a></li>
+<li class="isub4">qualitive test, <a href="#Page_419">419</a>, <a href="#Page_420">420</a></li>
+<li class="isub2">Proteids, action of acids, <a href="#Page_442">442</a></li>
+<li class="isub3">classification, <a href="#Page_410">410</a></li>
+<li class="isub3">diversity of character, <a href="#Page_434">434</a></li>
+<li class="isub3">estimation in cereals, <a href="#Page_543">543</a></li>
+<li class="isub5">koumiss, <a href="#Page_534">534</a></li>
+<li class="isub5">meats, <a href="#Page_550">550</a></li>
+<li class="isub5">milk, <a href="#Page_505">505</a></li>
+<li class="isub4">of digestible in cheese, <a href="#Page_531">531</a></li>
+<li class="isub3">general principles of separation, <a href="#Page_446">446</a></li>
+<li class="isub3">insoluble, <a href="#Page_413">413</a></li>
+<li class="isub3">kinds in milk, <a href="#Page_504">504</a></li>
+<li class="isub3">methods of drying, <a href="#Page_443">443</a>, <a href="#Page_444">444</a></li>
+<li class="isub4">precipitation, <a href="#Page_439">439</a></li>
+<li class="isub3">separation, soluble in water, <a href="#Page_439">439</a>, <a href="#Page_440">440</a></li>
+<li class="isub3">soluble in dilute alcohol, <a href="#Page_440">440</a></li>
+<li class="isub4">salt solution, <a href="#Page_438">438</a></li>
+<li class="isub4">water, <a href="#Page_436">436</a></li>
+<li class="isub3">solution in alkalies, <a href="#Page_442">442</a></li>
+<li class="isub2">Proteolytic ferments, <a href="#Page_557">557</a></li>
+<li class="isub2">Proteoses, definition and properties, <a href="#Page_412">412</a></li>
+<li class="isub3">separation, <a href="#Page_440">440</a></li>
+<li class="isub2">Protoalbumose, <a href="#Page_412">412</a></li>
+<li class="isub2">Pulfrich, refractometer, <a href="#Page_331">331</a>, <a href="#Page_333">333</a></li>
+<li class="isub2">Pumice stone, use in drying, <a href="#Page_33">33</a>, <a href="#Page_486">486</a></li>
+<li class="isub2">Purity, apparent, <a href="#Page_263">263</a></li>
+<li class="isub2">Pyknometer, formulas for calculating volume, <a href="#Page_67">67</a></li>
+<li class="isub3">use, <a href="#Page_63">63</a>, <a href="#Page_64">64</a></li>
+<li class="isub4">at high temperature, <a href="#Page_65">65</a>, <a href="#Page_66">66</a></li>
+<li class="isub2">Pyrogalol, reagent for furfurol determination, <a href="#Page_183">183</a></li>
+
+<li class="isub7 ifrst fs_120"><b>Q</b></li>
+<li class="isub2">Quartz plates, <a href="#Page_96">96</a>, <a href="#Page_97">97</a></li>
+<li class="isub3">applicability, <a href="#Page_98">98</a></li>
+<li class="isub3">corrections, <a href="#Page_97">97</a>, <a href="#Page_98">98</a></li>
+<li class="isub2">Quévenne, lactometer, <a href="#Page_466">466</a>
+<span class="pagenum"><a id="Page_661"></a>[Pg 661]</span></li>
+
+<li class="isub7 ifrst fs_120"><b>R</b></li>
+<li class="isub2">Raffinose, estimation, <a href="#Page_115">115</a></li>
+<li class="isub4">in presence of sucrose, <a href="#Page_266">266</a></li>
+<li class="isub3">gyrodynat, <a href="#Page_119">119</a></li>
+<li class="isub3">molecular weight, <a href="#Page_177">177</a></li>
+<li class="isub2">Raoul, method of determining molecular weights, <a href="#Page_175">175</a></li>
+<li class="isub2">Reducing sugars, estimation, <a href="#Page_234">234</a></li>
+<li class="isub4">in fermented beverages, <a href="#Page_632">632</a></li>
+<li class="isub3">factors for computation, <a href="#Page_141">141</a>, <a href="#Page_142">142</a></li>
+<li class="isub3">relation to quantity of copper suboxid, <a href="#Page_141">141</a></li>
+<li class="isub2">Refractive index of fats and oils, <a href="#Page_328">328</a></li>
+<li class="isub3">indices, <a href="#Page_333">333</a>, <a href="#Page_334">334</a></li>
+<li class="isub2">Refractometers, <a href="#Page_329">329</a>, <a href="#Page_333">333</a></li>
+<li class="isub3">variation, <a href="#Page_338">338</a></li>
+<li class="isub2">Regnault-Pfaundler, calorimetric formula, <a href="#Page_572">572</a></li>
+<li class="isub2">Reichert number, <a href="#Page_518">518</a>, <a href="#Page_519">519</a></li>
+<li class="isub2">Resorcin, qualitive test for levulose, <a href="#Page_191">191</a></li>
+<li class="isub2">Richmond, thermal reaction of oils, <a href="#Page_359">359</a>, <a href="#Page_360">360</a></li>
+<li class="isub2">Ritthausen, method of precipitating milk proteids, <a href="#Page_506">506</a></li>
+<li class="isub2">Roentgen rays, application to analyses, <a href="#Page_588">588</a></li>
+<li class="isub2">Rye starch, <a href="#Page_221">221</a></li>
+
+<li class="isub7 ifrst fs_120"><b>S</b></li>
+<li class="isub2">Saccharic acid, test for dextrose group, <a href="#Page_190">190</a></li>
+<li class="isub2">Sachsse’s method of determining amid bodies, <a href="#Page_424">424</a>, <a href="#Page_425">425</a></li>
+<li class="isub3">solution, <a href="#Page_122">122</a></li>
+<li class="isub2">Saffron, <a href="#Page_522">522</a></li>
+<li class="isub2">Safranin, detection in wines, <a href="#Page_637">637</a></li>
+<li class="isub2">Sago starch, <a href="#Page_220">220</a></li>
+<li class="isub2">Salicylic acid, detection in fermented beverages, <a href="#Page_638">638</a>, <a href="#Page_639">639</a></li>
+<li class="isub2">Salt, estimation in butter, <a href="#Page_516">516</a></li>
+<li class="isub2">Samples, collecting, <a href="#Page_5">5</a></li>
+<li class="isub3">grinding, <a href="#Page_6">6</a></li>
+<li class="isub3">preparation, <a href="#Page_3">3</a>, <a href="#Page_4">4</a></li>
+<li class="isub3">preserving, <a href="#Page_5">5</a></li>
+<li class="isub2">Sand, use in drying, <a href="#Page_486">486</a></li>
+<li class="isub2">Saponification, <a href="#Page_376">376</a>, <a href="#Page_384">384</a></li>
+<li class="isub3">chemical reactions, <a href="#Page_377">377</a>, <a href="#Page_378">378</a></li>
+<li class="isub3">equivalent, <a href="#Page_383">383</a></li>
+<li class="isub3">in the cold, <a href="#Page_381">381</a>, <a href="#Page_382">382</a></li>
+<li class="isub3">methods of conducting, <a href="#Page_378">378</a>, <a href="#Page_382">382</a></li>
+<li class="isub3">under pressure, <a href="#Page_379">379</a>, <a href="#Page_380">380</a></li>
+<li class="isub3">value, <a href="#Page_382">382</a>, <a href="#Page_383">383</a></li>
+<li class="isub4">of butter, <a href="#Page_518">518</a></li>
+<li class="isub3">with alcohol, <a href="#Page_381">381</a></li>
+<li class="isub3">without alcohol, <a href="#Page_381">381</a></li>
+<li class="isub2">Sarkin, <a href="#Page_416">416</a></li>
+<li class="isub3">composition, <a href="#Page_451">451</a></li>
+<li class="isub2">Sausages, occurrence of starch, <a href="#Page_553">553</a></li>
+<li class="isub2">Scheibler, double polarization, <a href="#Page_102">102</a></li>
+<li class="isub3">extraction tube, <a href="#Page_248">248</a></li>
+<li class="isub2">Schmidt, method of milk fat analysis, <a href="#Page_489">489</a></li>
+<li class="isub2">deSchweinitz and Emery, calorimetric distinction between</li>
+<li class="isub7">butter and oleomargarin, <a href="#Page_576">576</a></li>
+<li class="isub2">Schweitzer and Lungwitz, iodin addition, <a href="#Page_367">367</a>, <a href="#Page_368">368</a>
+                   <span class="pagenum"><a id="Page_662"></a>[Pg 662]</span></li>
+<li class="isub2">Scovell, milk sampler, <a href="#Page_470">470</a></li>
+<li class="isub2">Selenite plate, microscopic examination of starches, <a href="#Page_219">219</a></li>
+<li class="isub3">use in examination of fat crystals, <a href="#Page_343">343</a></li>
+<li class="isub2">Sesame oil, detection, <a href="#Page_402">402</a></li>
+<li class="isub3">furfurol reaction, <a href="#Page_521">521</a></li>
+<li class="isub2">Shadow polariscope, <a href="#Page_90">90</a></li>
+<li class="isub2">Short, method of milk fat analysis, <a href="#Page_490">490</a></li>
+<li class="isub2">Shredding apparatus, <a href="#Page_9">9</a>, <a href="#Page_10">10</a>, <a href="#Page_236">236</a></li>
+<li class="isub2">Sidersky, modification of Soldaini’s process, <a href="#Page_147">147</a></li>
+<li class="isub2">Sieben, method of determining levulose, <a href="#Page_280">280</a></li>
+<li class="isub2">Silver nitrate, color test with fats and oils, <a href="#Page_355">355</a></li>
+<li class="isub2">Sirups, analysis, <a href="#Page_254">254</a></li>
+<li class="isub3">determination of ash, <a href="#Page_256">256</a></li>
+<li class="isub4">reducing sugars, <a href="#Page_256">256</a></li>
+<li class="isub4">water, <a href="#Page_255">255</a></li>
+<li class="isub3">specific gravity, <a href="#Page_254">254</a></li>
+<li class="isub2">Sodium chlorid, reagent for extracting proteids, <a href="#Page_433">433</a></li>
+<li class="isub3">thiosulfate solution, preparation, <a href="#Page_369">369</a></li>
+<li class="isub2">Soldaini copper carbonate process, <a href="#Page_139">139</a>, <a href="#Page_140">140</a></li>
+<li class="isub3">gravimetric method, <a href="#Page_258">258</a></li>
+<li class="isub2">Soleil-Ventzke polariscope, <a href="#Page_88">88</a>, <a href="#Page_89">89</a></li>
+<li class="isub2">Solidifying point of fats and oils, <a href="#Page_326">326</a>, <a href="#Page_327">327</a></li>
+<li class="isub2">Soluble acids, estimation in butter, <a href="#Page_517">517</a></li>
+<li class="isub3">fat acids, determination, <a href="#Page_389">389</a>, <a href="#Page_390">390</a></li>
+<li class="isub2">Solvent, recovery, <a href="#Page_53">53</a>, <a href="#Page_55">55</a></li>
+<li class="isub3">in open dish, <a href="#Page_55">55</a></li>
+<li class="isub2">Solvents, <a href="#Page_52">52</a>, <a href="#Page_53">53</a></li>
+<li class="isub3">object, <a href="#Page_40">40</a></li>
+<li class="isub2">Sour milk, density, <a href="#Page_477">477</a></li>
+<li class="isub2">Soxhlet, areometric method of milk fat estimation, <a href="#Page_492">492</a>, <a href="#Page_494">494</a></li>
+<li class="isub3">extraction apparatus, <a href="#Page_47">47</a></li>
+<li class="isub2">Specific gravity, areometric method, <a href="#Page_70">70</a></li>
+<li class="isub4">determination in distillate, <a href="#Page_615">615</a></li>
+<li class="isub4">example, <a href="#Page_68">68</a></li>
+<li class="isub4">method of expressing, <a href="#Page_319">319</a></li>
+<li class="isub4">standard of comparison, <a href="#Page_320">320</a></li>
+<li class="isub3">heats of materials in calorimeter, <a href="#Page_573">573</a></li>
+<li class="isub3">rotatory power, <a href="#Page_115">115</a>, <a href="#Page_116">116</a></li>
+<li class="isub4">causes of variation, <a href="#Page_117">117</a></li>
+<li class="isub2">Spectroscopy, oils and fats, <a href="#Page_348">348</a></li>
+<li class="isub2">Spencer, air-drying oven, <a href="#Page_17">17</a></li>
+<li class="isub3">method of estimating caffein, <a href="#Page_583">583</a></li>
+<li class="isub3">observation tube, <a href="#Page_253">253</a></li>
+<li class="isub2">Spheroidal state, melting point, <a href="#Page_323">323</a>, <a href="#Page_326">326</a></li>
+<li class="isub2">Sponge, use in drying, <a href="#Page_486">486</a></li>
+<li class="isub2">Spongin, <a href="#Page_416">416</a></li>
+<li class="isub2">Stannic bromate, color test with fats and oils, <a href="#Page_356">356</a></li>
+<li class="isub2">Starch, colorimetric estimation, <a href="#Page_210">210</a></li>
+<li class="isub3">composition, <a href="#Page_196">196</a></li>
+<li class="isub3">disturbing bodies in estimation, <a href="#Page_209">209</a></li>
+<li class="isub3">estimation in potatoes, <a href="#Page_301">301</a>, <a href="#Page_302">302</a></li>
+<li class="isub5">sausages, <a href="#Page_553">553</a></li>
+<li class="isub4">of ash, <a href="#Page_203">203</a></li>
+<li class="isub5">nitrogen, <a href="#Page_203">203</a></li>
+<li class="isub5">water, <a href="#Page_202">202</a>, <a href="#Page_299">299</a></li>
+<li class="isub4">with barium hydroxid, <a href="#Page_208">208</a>
+              <span class="pagenum"><a id="Page_663"></a>[Pg 663]</span></li>
+<li class="isub3">factor for calculating from dextrose, <a href="#Page_205">205</a></li>
+<li class="isub3">fixation of iodin, <a href="#Page_211">211</a></li>
+<li class="isub3">gyrodynat of soluble, <a href="#Page_206">206</a></li>
+<li class="isub3">hydrolysis at high temperatures, <a href="#Page_199">199</a></li>
+<li class="isub4">in an autoclave, <a href="#Page_199">199</a>, <a href="#Page_200">200</a></li>
+<li class="isub4">with acids, <a href="#Page_203">203</a>, <a href="#Page_204">204</a></li>
+<li class="isub3">occurrence, <a href="#Page_298">298</a></li>
+<li class="isub4">in tobacco, <a href="#Page_604">604</a></li>
+<li class="isub3">particles, separation, <a href="#Page_197">197</a></li>
+<li class="isub3">polarization, <a href="#Page_205">205</a></li>
+<li class="isub3">principles of determination, <a href="#Page_201">201</a></li>
+<li class="isub3">properties, <a href="#Page_196">196</a></li>
+<li class="isub3">rapid estimation, <a href="#Page_207">207</a></li>
+<li class="isub3">separation, <a href="#Page_399">399</a></li>
+<li class="isub3">solution at high pressure, <a href="#Page_206">206</a></li>
+<li class="isub4">in nitric acid, <a href="#Page_206">206</a></li>
+<li class="isub2">Starches, classification, <a href="#Page_218">218</a></li>
+<li class="isub3">description of typical, <a href="#Page_219">219</a></li>
+<li class="isub3">identification, <a href="#Page_211">211</a></li>
+<li class="isub3">microscopic examination, <a href="#Page_219">219</a></li>
+<li class="isub3">occurrence in the juices of plants, <a href="#Page_228">228</a></li>
+<li class="isub2">Steam coil oven, <a href="#Page_20">20</a>, <a href="#Page_21">21</a></li>
+<li class="isub2">Stearin, <a href="#Page_310">310</a></li>
+<li class="isub2">Stone, method of estimating pentosans, <a href="#Page_181">181</a></li>
+<li class="isub2">Strontium saccharates, <a href="#Page_187">187</a></li>
+<li class="isub2">Stutzer, artificial digestion of cheese, <a href="#Page_561">561</a></li>
+<li class="isub3">method of estimating gelatin, <a href="#Page_457">457</a></li>
+<li class="isub2">Succinic acid, estimation in fermented beverages, <a href="#Page_630">630</a>, <a href="#Page_631">631</a></li>
+<li class="isub2">Sucrose, cobaltous nitrate test, <a href="#Page_189">189</a></li>
+<li class="isub3">estimation in coffee, <a href="#Page_586">586</a></li>
+<li class="isub4">presence of dextrose, <a href="#Page_274">274</a></li>
+<li class="isub5">levulose and dextrose, <a href="#Page_280">280</a>, <a href="#Page_285">285</a></li>
+<li class="isub5">raffinose, <a href="#Page_266">266</a></li>
+<li class="isub3">molecular weight, <a href="#Page_176">176</a></li>
+<li class="isub3">occurrence, <a href="#Page_264">264</a></li>
+<li class="isub3">pipette, <a href="#Page_231">231</a>, <a href="#Page_232">232</a></li>
+<li class="isub3">qualitive optical test, <a href="#Page_188">188</a></li>
+<li class="isub3">separation and estimation, <a href="#Page_264">264</a></li>
+<li class="isub2">Sugar analysis, chemical methods, <a href="#Page_120">120</a></li>
+<li class="isub3">classification of methods, <a href="#Page_61">61</a>, <a href="#Page_62">62</a></li>
+<li class="isub3">general remarks, <a href="#Page_104">104</a></li>
+<li class="isub3">gravimetric copper methods, <a href="#Page_149">149</a>, <a href="#Page_170">170</a></li>
+<li class="isub4">Halle method, <a href="#Page_153">153</a>, <a href="#Page_155">155</a></li>
+<li class="isub3">laboratory gravimetric method, <a href="#Page_150">150-153</a></li>
+<li class="isub3">permanganate process, <a href="#Page_132">132-135</a></li>
+<li class="isub3">volumetric laboratory method, <a href="#Page_129">129</a>, <a href="#Page_130">130</a></li>
+<li class="isub4">methods, <a href="#Page_121">121</a></li>
+<li class="isub2">Sugar beets, analysis, <a href="#Page_242">242</a></li>
+<li class="isub4">apparatus for grinding, <a href="#Page_10">10</a></li>
+<li class="isub4">extraction with alcohol, <a href="#Page_245">245</a>, <a href="#Page_247">247</a></li>
+<li class="isub3">content in maple sap, <a href="#Page_228">228</a></li>
+<li class="isub3">direct determination in canes, <a href="#Page_235">235</a></li>
+<li class="isub3">estimation in cane and beet pulp, <a href="#Page_238">238</a></li>
+<li class="isub4">sap, <a href="#Page_228">228-230</a></li>
+<li class="isub4">sugar beets, <a href="#Page_242">242</a></li>
+<li class="isub3">extraction from plants, <a href="#Page_230">230</a>
+                <span class="pagenum"><a id="Page_664"></a>[Pg 664]</span></li>
+<li class="isub3">flask, diffusion and alcohol digestion, <a href="#Page_245">245</a></li>
+<li class="isub2">Sugar flasks, <a href="#Page_98">98</a>, <a href="#Page_99">99</a></li>
+<li class="isub3">instantaneous diffusion, <a href="#Page_243">243</a></li>
+<li class="isub3">juices, preservation, <a href="#Page_235">235</a></li>
+<li class="isub3">mills, <a href="#Page_230">230</a></li>
+<li class="isub3">preparation of pure, <a href="#Page_60">60</a></li>
+<li class="isub3">removal from starchy bodies, <a href="#Page_300">300</a></li>
+<li class="isub3">solutions, preparation for polarization, <a href="#Page_99">99-104</a></li>
+<li class="isub4">specific gravity, <a href="#Page_62">62</a></li>
+<li class="isub2">Sugars, determination in dried material, <a href="#Page_239">239</a></li>
+<li class="isub4">without weighing, <a href="#Page_253">253</a></li>
+<li class="isub3">estimation in fermented beverages, <a href="#Page_632">632</a>, <a href="#Page_635">635</a></li>
+<li class="isub3">hexose, <a href="#Page_59">59</a></li>
+<li class="isub3">miscellaneous qualitive tests, <a href="#Page_193">193</a></li>
+<li class="isub3">occurrence in tobacco, <a href="#Page_604">604</a></li>
+<li class="isub3">optical properties, <a href="#Page_74">74</a>, <a href="#Page_75">75</a></li>
+<li class="isub3">pentose, <a href="#Page_59">59</a></li>
+<li class="isub3">qualitive tests, <a href="#Page_188">188</a></li>
+<li class="isub3">separation by lead oxid, <a href="#Page_284">284</a>, <a href="#Page_285">285</a></li>
+<li class="isub3">state of existence in plants, <a href="#Page_227">227</a></li>
+<li class="isub2">Sulfur chlorid, reagent for oils, <a href="#Page_402">402</a>, <a href="#Page_403">403</a></li>
+<li class="isub3">determination in proteids, <a href="#Page_446">446</a></li>
+<li class="isub3">loss of organic in combustion, <a href="#Page_37">37</a></li>
+<li class="isub2">Sulfuric acid, color test for fats and oils, <a href="#Page_352">352</a></li>
+<li class="isub4">estimation in tobacco, <a href="#Page_600">600</a></li>
+<li class="isub3">saponification, <a href="#Page_357">357</a>, <a href="#Page_358">358</a></li>
+<li class="isub2">Sulfurous acid, elimination, <a href="#Page_519">519</a></li>
+<li class="isub3">estimation in fermented beverage, <a href="#Page_638">638</a></li>
+
+<li class="isub7 ifrst fs_120"><b>T</b></li>
+<li class="isub2">Tannic acid, estimation in tobacco, <a href="#Page_604">604</a></li>
+<li class="isub3">reagent for milk proteids, <a href="#Page_507">507</a></li>
+<li class="isub2">Tannin, composition, <a href="#Page_588">588</a></li>
+<li class="isub3">detection, <a href="#Page_589">589</a>, <a href="#Page_593">593</a></li>
+<li class="isub3">estimation <a href="#Page_589">589</a>, <a href="#Page_596">596</a></li>
+<li class="isub4">by hide powder method, <a href="#Page_590">590</a>, <a href="#Page_592">592</a></li>
+<li class="isub3">infusion, preparation, <a href="#Page_596">596</a></li>
+<li class="isub3">occurrence, <a href="#Page_588">588</a></li>
+<li class="isub3">permanganate gelatin method, <a href="#Page_593">593</a>, <a href="#Page_594">594</a></li>
+<li class="isub3">precipitation with metallic salts, <a href="#Page_589">589</a></li>
+<li class="isub2">Tartaric acid, estimation in wine, <a href="#Page_229">229</a>, <a href="#Page_230">230</a></li>
+<li class="isub2">Tea and coffee, <a href="#Page_582">582</a></li>
+<li class="isub2">Thein, <a href="#Page_583">583</a></li>
+<li class="isub2">Thermal reactions, fats and oils, <a href="#Page_356">356</a>, <a href="#Page_363">363</a></li>
+<li class="isub2">Thermostat for steam bath, <a href="#Page_15">15</a></li>
+<li class="isub2">Thörner, method of milk fat analysis, <a href="#Page_491">491</a></li>
+<li class="isub2">Tobacco, acid and basic constituents, <a href="#Page_597">597</a></li>
+<li class="isub3">burning qualities, <a href="#Page_608">608</a></li>
+<li class="isub3">composition, <a href="#Page_598">598</a>, <a href="#Page_599">599</a></li>
+<li class="isub4">of ash, <a href="#Page_598">598</a></li>
+<li class="isub3">fermentation, <a href="#Page_596">596</a>, <a href="#Page_597">597</a></li>
+<li class="isub3">fractional extraction, <a href="#Page_608">608</a></li>
+<li class="isub2">Tollens and Günther, method of estimating pentosans, <a href="#Page_180">180</a></li>
+<li class="isub2">Torsion Viscosimeter, <a href="#Page_342">342</a></li>
+<li class="isub2">Total solids, calculation, <a href="#Page_478">478</a></li>
+<li class="isub3">formulas for calculating, <a href="#Page_479">479</a>, <a href="#Page_480">480</a></li>
+<li class="isub2">Trinitroalbumin, <a href="#Page_411">411</a></li>
+<li class="isub2">Triple shadow polariscope, <a href="#Page_91">91</a>, <a href="#Page_92">92</a></li>
+<li class="isub2">Tropæolin, detection in wines, <a href="#Page_637">637</a>
+               <span class="pagenum"><a id="Page_665"></a>[Pg 665]</span></li>
+<li class="isub2">Turbidity temperature, fats and oils, <a href="#Page_351">351</a></li>
+<li class="isub2">Turmeric, <a href="#Page_522">522</a></li>
+<li class="isub2">Tyrosin, <a href="#Page_412">412</a></li>
+<li class="isub3">occurrence in milk, <a href="#Page_464">464</a></li>
+<li class="isub2">Tyrotoxicon, occurrence in milk, <a href="#Page_464">464</a></li>
+
+<li class="isub7 ifrst fs_120"><b>U</b></li>
+<li class="isub2">Ulsch, drying oven, <a href="#Page_31">31</a></li>
+<li class="isub2">Unicedin, <a href="#Page_413">413</a></li>
+<li class="isub2">Urea, occurrence, in milk, <a href="#Page_464">464</a></li>
+
+<li class="isub7 ifrst fs_120"><b>V</b></li>
+<li class="isub2">Vacuum, drying, <a href="#Page_18">18</a></li>
+<li class="isub2">Van Slyke, method of estimating casein, <a href="#Page_508">508</a></li>
+<li class="isub2">Vegetable substances, preparation, <a href="#Page_3">3</a>, <a href="#Page_4">4</a></li>
+<li class="isub2">Vegetables, sampling, <a href="#Page_577">577</a></li>
+<li class="isub2">Vinolin, detection in wines, <a href="#Page_637">637</a></li>
+<li class="isub2">Viscosimetry, <a href="#Page_342">342</a>, <a href="#Page_345">345</a></li>
+<li class="isub2">Viscosity of fats and oils, <a href="#Page_342">342</a></li>
+<li class="isub2">Viscous liquids, drying, <a href="#Page_32">32</a>, <a href="#Page_33">33</a></li>
+<li class="isub2">Vitellin, <a href="#Page_411">411</a></li>
+<li class="isub2">Vogel, table for identifying starches, <a href="#Page_212">212</a>, <a href="#Page_213">213</a></li>
+<li class="isub2">Volatile acids, estimation in butter, <a href="#Page_517">517</a></li>
+<li class="isub5">fermented beverages, <a href="#Page_627">627</a>, <a href="#Page_628">628</a></li>
+<li class="isub3">bodies, drying, <a href="#Page_13">13</a></li>
+<li class="isub3">fat acids, determination, <a href="#Page_386">386</a>, <a href="#Page_388">388</a></li>
+<li class="isub4">distillation, <a href="#Page_387">387</a>, <a href="#Page_388">388</a></li>
+<li class="isub4">titration, <a href="#Page_388">388</a></li>
+<li class="isub2">Volume of precipitate, calculation, <a href="#Page_279">279</a></li>
+
+<li class="isub7 ifrst fs_120"><b>W</b></li>
+<li class="isub2">Water, action on composition of proteids, <a href="#Page_437">437</a></li>
+<li class="isub3">estimation in butter, <a href="#Page_515">515</a></li>
+<li class="isub4">cereals, <a href="#Page_542">542</a></li>
+<li class="isub4">fermented beverages, <a href="#Page_626">626</a></li>
+<li class="isub4">fruits and vegetables, <a href="#Page_578">578</a></li>
+<li class="isub4">koumiss, <a href="#Page_536">536</a></li>
+<li class="isub4">meats, <a href="#Page_549">549</a></li>
+<li class="isub4">tobacco, <a href="#Page_599">599</a></li>
+<li class="isub2">Watermelons, composition, <a href="#Page_581">581</a>, <a href="#Page_582">582</a></li>
+<li class="isub2">Wax, occurrence in tobacco, <a href="#Page_608">608</a></li>
+<li class="isub2">Waxes, composition, <a href="#Page_309">309</a></li>
+<li class="isub2">Westphal balance, <a href="#Page_69">69</a></li>
+<li class="isub2">Wheat starch, <a href="#Page_221">221</a></li>
+<li class="isub2">Wiechmann, formula for calculating sugars, <a href="#Page_307">307</a></li>
+<li class="isub3">method of estimating levulose, sucrose and dextrose, <a href="#Page_280">280</a>, <a href="#Page_281">281</a></li>
+<li class="isub2">Williams, calorimeter, <a href="#Page_570">570</a></li>
+<li class="isub2">Winter, estimation of levulose and dextrose</li>
+<li class="isub7">in presence of sucrose, <a href="#Page_283">283</a>, <a href="#Page_284">284</a></li>
+<li class="isub2">Wood pulp, use in drying, <a href="#Page_486">486</a></li>
+<li class="isub2">Wrampelmayer, drying oven, <a href="#Page_30">30</a></li>
+
+<li class="isub7 ifrst fs_120"><b>X</b></li>
+<li class="isub2">Xanthin, <a href="#Page_416">416</a></li>
+<li class="isub2">Xanthoproteic reaction, <a href="#Page_420">420</a></li>
+<li class="isub2">Xylan, occurrence, <a href="#Page_586">586</a></li>
+
+<li class="isub7 ifrst fs_120"><b>Y</b></li>
+<li class="isub2">Yeast, inversion, <a href="#Page_113">113</a></li>
+
+<li class="isub7 ifrst fs_120"><b>Z</b></li>
+<li class="isub2">Zein, <a href="#Page_441">441</a></li>
+<li class="isub2">Zeiss, butyrorefractometer, <a href="#Page_339">339</a>, <a href="#Page_341">341</a></li>
+<li class="isub2">Zinc, occurrence, in evaporated fruits, <a href="#Page_380">380</a>, <a href="#Page_581">581</a></li>
+<li class="isub3">sulfate, reagent for precipitating proteids, <a href="#Page_433">433</a></li>
+<li class="isub3">separating albumoses from peptones, <a href="#Page_455">455</a></li>
+</ul>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum"><a id="Page_666"></a>[Pg 666]</span></p>
+<h2 class="nobreak">CORRECTIONS FOR VOL. I.</h2>
+</div>
+
+<div class="blockquot">
+<p class="neg-indent">Page 5, 11th line, insert “ten” before “thousand.”</p>
+
+<p class="neg-indent">Page 21, read “Magdeburg” instead of “Madgeburg” in both instances.</p>
+
+<p class="neg-indent">Page 61, for per cent. of oxygen in ulmin read “28.7” instead of “8.7.”</p>
+
+<p class="neg-indent">Page 62, for per cent. of carbon in apocrenic acid read “54.4” instead of “34.4.”</p>
+
+<p class="neg-indent">Page 112, 2d line from bottom, read “14” instead of “13.”</p>
+
+<p class="neg-indent">Page 140, the sentence beginning “The burette is lowered etc.” is
+repeated. <i>Dele</i> one of them.</p>
+
+<p class="neg-indent">Page 141, 6th line, insert “or air dried” after “moisture.”</p>
+
+<p class="neg-indent">Page 141, in example read 10.25, 10.22, 13.07 and 76.21 for 9.52, 9.22,
+12.07, and 60.35 respectively.</p>
+
+<p class="neg-indent">Page 158, 3d line of <b>172</b>, insert “and estimating soluble matters
+therein” after “flow.”</p>
+
+<p class="neg-indent">Page 159, omit “√<span class="over">&nbsp;&emsp;&nbsp;</span>” in first formula.</p>
+
+<p class="neg-indent">Page 293, 12th line, read “U” for “V.”</p>
+
+<p class="neg-indent">Page 309, last line, read “sixth” for “sixteenth.”</p>
+
+<p class="neg-indent">Page 312, 1st line, read “atmosphere” instead of “room.”</p>
+
+<p class="neg-indent">Page 315, 6th and 7th lines, read <b>299</b>, and <b>300</b>, for
+<b>294</b>, and <b>295</b>, respectively.</p>
+
+<p class="neg-indent">Page 323, 3d line from bottom, read <b>301</b> for <b>299</b>.</p>
+
+<p class="neg-indent">Page 333, 5th line of <b>316</b>, insert after “is” “to eliminate
+carbon dioxid and.”</p>
+
+<p class="neg-indent">Page 354, 3d line from end of (6) insert after “solution” “acidified
+with acetic and;” same line, transfer “r” from “ther,” to “pecipitate.”</p>
+
+<p class="neg-indent">Page 357, 6th line from end of (4) insert after “difference” “and the
+phosphoric acid estimated as in <b>380</b>, deducted therefrom.”</p>
+
+<p class="neg-indent">Page 367, 4th line, add after “taken,” “The phosphoric acid may be
+determined as described in <b>372</b>, or following paragraphs.”</p>
+
+<p class="neg-indent">Page 410, line 21, <i>dele</i> “dilute” and insert “one per cent
+nitric.”</p>
+
+<p class="neg-indent">Page 410, line 25, after “capsule” insert “adding water once or twice.”</p>
+
+<p class="neg-indent">Page 449, 4th line read “hydrobromic” for “hydrochloric.”</p>
+
+<p class="neg-indent">Page 457, reference “30” read “Band 38” instead of “Band 37.”</p>
+
+<p class="neg-indent">Page 468, 8th line, <i>dele</i> “or gypsum” and read “200” instead of
+“50.”</p>
+
+<p class="neg-indent">Page 471, last line, read “not” for “very.”</p>
+
+<p class="neg-indent">Page 472, 4th line, insert “un” before “successful.”</p>
+
+<p class="neg-indent">Page 496, 5th line, insert “the” before “soil.”</p>
+
+<p class="neg-indent">Page 515, next to last and last lines, read “stannous” instead of
+“zinc.”</p>
+
+<p class="neg-indent">Page 516, second line, read “stannous” instead of “zinc.”</p>
+
+<p class="neg-indent">Page 557, 9th line of <b>500</b> read “red-yellow” instead of “blue.”</p>
+</div>
+
+<h2 class="nobreak">CORRECTIONS FOR VOL. II.</h2>
+<div class="blockquot">
+
+<p class="neg-indent">Page 14, line 21, read “61.74 per cent.” for “16.74 per cent.”</p>
+
+<p class="neg-indent">Page 23, 8th line from bottom, read “0.0025.” for “0.0035.”</p>
+
+<p class="neg-indent">Page 54, 9th line, read “white” instead of “yellow.”</p>
+
+<p class="neg-indent">Page 54, 13th line, read “phosphate” instead of “phosphomolybdate.”
+<span class="pagenum"><a id="Page_667"></a>[Pg 667]</span></p>
+
+<p class="neg-indent">Page 57, 8th line from bottom, read “saturated” instead of “citrate.”</p>
+
+<p class="neg-indent">Page 73, read “Kosmann” in 10th line of paragraph <b>72</b> for “Kormann.”</p>
+
+<p class="neg-indent">Page 158, reference number 72, read “1889” instead of “1888.”</p>
+</div>
+
+<h2 class="nobreak">CORRECTIONS FOR VOL. III.</h2>
+<div class="blockquot">
+
+<p class="neg-indent">Page 11, name of Figure 4 read “Dreef” instead of “Dree.”</p>
+
+<p class="neg-indent">Page 40, fifth and seventh lines, read “Courtonne” instead of “Courtoune.”</p>
+
+<p class="neg-indent">Page 59, eighth line from bottom, insert “original” before “optical.”</p>
+
+<p class="neg-indent">Page 60, second line, read “<i>d</i>” instead of “<i>l</i>” before “fructose.”</p>
+
+<p class="neg-indent">Page 68, legend of Figure 29, read “areometers” instead of “aereometers.”</p>
+
+<p class="neg-indent">Page 146, sixth line from bottom, insert “cyanid” after “potassium.”</p>
+
+<p class="neg-indent">Page 159, instead of headings for table as given, substitute those on
+page 160.</p>
+
+<p class="neg-indent">Page 177, in formula for lactose, read “H₂₂” instead of “H₃₂”; in formula
+for arabinose, read “H₁₀” instead of “H₁₉.”</p>
+
+<p class="neg-indent">Page 180, seventh line from bottom, read “Günther” instead of “Gunther.”</p>
+
+<p class="neg-indent">Page 191, read paragraph <b>169</b>. Seventh line read “resorcin” instead
+of “resorsin.”</p>
+
+<p class="neg-indent">Page 268, legend of Figure 77, read “Desiccating” instead of “Dessicating.”</p>
+
+<p class="neg-indent">Page 288, in formula (2) read “53d” instead of “54d.”</p>
+
+<p class="neg-indent">Pages 328, 329 and 334, read “Amagat” instead of “Armagat.”</p>
+
+<p class="neg-indent">Page 348, fourth line from bottom, omit accent in “sesame.”</p>
+
+<p class="neg-indent">Page 365, (b) first line, read 24.8 instead of 24.6.</p>
+
+<p class="neg-indent">Page 424, 4th line from bottom, read “nitrites” instead of “nitrates.”</p>
+
+<p class="neg-indent">Page 425, 4th and 5th lines, read “nitrite” instead of “nitrate.”</p>
+
+<p class="neg-indent">Page 445, in table of factors for computing proteids under Maize Proteids,
+read “16.06 and 6.22” instead of “15.64 and 6.39” respectively.</p>
+
+<p class="neg-indent">Page 451, sixth line from bottom, read “occur” instead of “occurs.”</p>
+
+<p class="neg-indent">Page 464, twelfth line from bottom, <i>dele</i> “food.”</p>
+
+<p class="neg-indent">Page 499, ninth line from bottom, read “Babcock.”</p>
+
+<p class="neg-indent">Page 543, sixteenth line, read “6.06 and 6.22” for “6.31 and 6.39”
+respectively.</p>
+
+<p class="neg-indent">Pages 555-556, read “amylolytic” for “amylytic.”</p>
+
+<p class="neg-indent">Page 555, fifth and seventeenth lines from bottom, insert after “into
+dextrin, maltose.”</p>
+
+<p class="neg-indent">Page 572, second equation, read “<i>tʹ</i>ₙ₂” instead of “<i>tʹ</i>ₙ₁.”</p>
+
+<p class="neg-indent">Page 573, 3rd line from bottom, read “stirring” for “storing.”</p>
+
+<p class="neg-indent">Page 574, 6th line from bottom, read “Θ₄” for “O_4.”</p>
+
+<p class="neg-indent">Page 575, 16th line from bottom, insert “one gram of” before “substance.”</p>
+
+<p class="neg-indent">Page 576 instead of 567, fourth line of paragraph 566, read “Calorie”
+instead of “calorie.”</p>
+
+<p class="neg-indent">Page 644, <i>dele</i> “Band 12, Ss. 64 und 199” in reference 94.</p>
+</div>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<div class="transnote bbox spa2">
+<p class="f120 spa1">Transcriber’s Notes:</p>
+<hr class="r10">
+<p>The cover image was created by the transcriber, and is in the public domain.</p>
+<p>New original cover art included with this eBook is granted to the public domain.</p>
+<p>Deprecated spellings were not corrected.</p>
+<p>The illustrations have been moved so that they do not break up
+      paragraphs and so that they are next to the text they illustrate.</p>
+<p>Typographical and punctuation errors have been silently corrected.</p>
+</div></div>
+
+<div style='text-align:center'>*** END OF THE PROJECT GUTENBERG EBOOK 75389 ***</div>
+</body>
+</html>
+
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author	nfenwick <nfenwick@pglaf.org>	2025-02-16 11:21:20 -0800
committer	nfenwick <nfenwick@pglaf.org>	2025-02-16 11:21:20 -0800
commit	0acc48572d38f314e60a112a861a6b10968a2876 (patch)
tree	7a0ba89cc482f84b0384f0365f48a572b92a3f85 /75389-h