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diff --git a/15576-8.txt b/15576-8.txt new file mode 100644 index 0000000..851754c --- /dev/null +++ b/15576-8.txt @@ -0,0 +1,11158 @@ +The Project Gutenberg EBook of A System of Instruction in the Practical +Use of the Blowpipe, by Anonymous + +This eBook is for the use of anyone anywhere at no cost and with +almost no restrictions whatsoever. You may copy it, give it away or +re-use it under the terms of the Project Gutenberg License included +with this eBook or online at www.gutenberg.org + + +Title: A System of Instruction in the Practical Use of the Blowpipe + Being A Graduated Course Of Analysis For The Use Of Students + And All Those Engaged In The Examination Of Metallic + Combinations + +Author: Anonymous + +Release Date: April 7, 2005 [EBook #15576] + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK USE OF THE BLOWPIPE *** + + + + +Produced by Curtis Weyant, Victoria Woosley and the PG +Online Distributed Proofreading Team at www.pgdp.net. + + + + + + + A + SYSTEM OF INSTRUCTION + IN + THE PRACTICAL USE + OF + THE BLOWPIPE. + + + BEING A GRADUATED COURSE OF ANALYSIS FOR THE USE OF STUDENTS + AND ALL THOSE ENGAGED IN THE EXAMINATION OF METALLIC + COMBINATIONS. + + + NEW YORK: + H. BAILLIÈRE, 290 BROADWAY, + AND 219 REGENT STREET, LONDON. + + PARIS: J.B. BAILLIÈRE ET FILS, RUE HAUTEFEUILLE. + MADRID: C. BAILLY-BAILLIÈRE, CALLE DEL PRINCIPE. + 1858. + + * * * * * + + ENTERED according to Act of Congress, in the year 1858, by + C.E. BAILLIÈRE, + In the Clerk's Office of the District Court of the United States, + for the Southern District of New York. + + + W.H. TINSON, Printer and Stereotyper, 43 Centre Street. + + * * * * * + + + + +TABLE OF CONTENTS. + + +PART I. + +Preface, 7 +The Use of the Blowpipe, 9 +Utensils--The Blowpipe, 12 +The Oil Lamp, 22 +The Spirit Lamp, 23 +Charcoal Support, 24 +Platinum Supports, 26 +Iron Spoons, 28 +Glass Tubes, 28 +Other Apparatus necessary, 31 +THE REAGENTS, 34 + Reagents of General Use, 34 + Carbonate of Soda, 34 + Hydrate of Baryta, 35 + Bi-sulphate of Potassa, 35 + Oxalate of Potassa, 36 + Cyanide of Potassium, 36 +Nitrate of Potassa, 37 + Borax, 38 + Microcosmic Salt, 39 + Nitrate of Cobalt, 40 + Tin, 41 + Silica, 42 + Test Papers, 42 +ESPECIAL REAGENTS, 43 + Boracic Acid, 43 + Fluorspar, 43 + Oxalate of Nickel, 43 + Oxide of Copper, 43 + Antimoniate of Potassa, 44 + Silver Foil, 44 + Nitroprusside of Sodium, 44 + + +PART II. + +Initiatory Analysis, 47 +Examination with the Glass Bulb, 47 + " in the Open Tube, 52 + " upon Charcoal, 55 + " in the Platinum Forceps, 61 + " in the Borax Bead, 69 + " in Microcosmic Salt, 72 +Table I.--Colors of Beads of Borax and Microcosmic Salt, 75 +Table II.--Behavior of Metallic Oxydes with Borax and + Microcosmic Salt, 85 +Examinations with Carbonate of Soda, 103 + + +PART III. + +Special Reactions, 109 +A.--METALLIC OXIDES: + First Group.--The Alkalies: Potassa, Soda, Ammonia, and Lithia, 110 + Second Group.--The Alkaline Earths: Baryta, Strontia, Lime, + and Magnesia, 115 + Third Group.--The Earths: Alumina, Glucina, Yttria, Thorina, + and Zirconia, 121 + Fourth Group.--Cerium, Lanthanium, Didymium, Columbium, + Niobium, Pelopium, Titanium, Uranium, Vanadium, Chromium, + Manganese, 124 + Fifth Group.--Iron, Cobalt, Nickel, 135 + Sixth Group.--Zinc, Cadmium, Antimony, Tellurium, 140 + Seventh Group.--Lead, Bismuth, Tin, 149 + Eighth Group.--Mercury, Arsenic, 157 + Ninth Group.--Copper, Silver, Gold, 161 + Tenth Group.--Molybdenum, Osmium, 165 + Eleventh Group.--Platinum, Palladium, Iridium, Rhodium, + Ruthenium, 167 + +Non-Metallic Substances, 168 + + +Tabular Statement of the Reactions of Minerals before + the Blowpipe, 178 + Carbon and Organic Minerals, 181 + Potassa, 184 + Soda, 186 + Baryta and Strontia, 190 + Lime, 192 + Magnesia, 196 + Alumina, 200 + Silicates, 204 + Uranium, 212 + Iron, 214 + Manganese, 222 + Nickel and Cobalt, 226 + Zinc, 232 + Bismuth, 234 + Lead, 238 + Copper, 248 + Antimony, 256 + Arsenic, 260 + Mercury, 262 + Silver, 264 + + * * * * * + + + + +PREFACE. + + +It is believed the arrangement of the present work is superior to that +of many of its predecessors, as a vehicle for the facilitation of the +student's progress. While it does not pretend to any other rank than +as an introduction to the larger works, it is hoped that the +arrangement of its matter is such that the beginner may more readily +comprehend the entire subject of Blowpipe Analysis than if he were to +begin his studies by the perusal of the more copious works of +Berzelius and Plattner. + +When the student shall have gone through these pages, and repeated the +various reactions described, then he will be fully prepared to enter +upon the study of the larger works. To progress through them will then +be but a comparatively easy task. + +The arrangement of this little work has been such as the author and +his friends have considered the best that could be devised for the +purpose of facilitating the progress of the student. Whether we have +succeeded is left for the public to decide. The author is indebted to +several of his friends for valuable contributions and suggestions. + +S. + +CINCINNATI, _June, 1857_. + +* * * * * + + + + THE BLOWPIPE. + + + + +* * * * * + + + + +Part First. + +THE USE OF THE BLOWPIPE. + + +Perhaps during the last fifty years, no department of chemistry has +been so enriched as that relating to analysis by means of the +Blowpipe. + +Through the unwearied exertions of men of science, the use of this +instrument has arrived to such a degree of perfection, that we have a +right to term its use, "Analysis in the _dry_ way," in contradistinction +to analysis "in the _wet_ way." The manipulations are so simple and +expeditious, and the results so clear and characteristic, that the +Blowpipe analysis not only verifies and completes the results of +analysis in the wet way, but it gives in many cases direct evidences +of the presence or absence of many substances, which would not be +otherwise detected, but through a troublesome and tedious process, +involving both prolixity and time; for instance, the detection of +manganese in minerals. + +Many substances have to go through Blowpipe manipulations before they +can be submitted to an analysis in the wet way. The apparatus and +reagents employed are compendious and small in number, so that they +can be carried easily while on scientific excursions, a considerable +advantage for mineralogists and metallurgists. + +The principal operations with the Blowpipe may be explained briefly as +follows: + + +(_a._) By _Ignition_ is meant the exposure of a substance to such a +degree of heat, that it glows or emits light, or becomes red-hot. Its +greatest value is in the separation of a volatile substance from one +less volatile, or one which is entirely fixed at the temperature of +the flame. In this case we only take cognizance of the latter or fixed +substance, although in many instances we make use of ignition for the +purpose of changing the conditions of a substance, for example, the +sesquioxide of chromium (Cr^{2}O^{3}) in its insoluble modification; +and as a preliminary examination for the purpose of ascertaining +whether the subject of inquiry be a combination of an organic or +inorganic nature. + +The apparatus used for this purpose are crucibles of platinum or +silver, platinum foil, a platinum spoon, platinum wire or tongs, +charcoal, glass tubes, and iron spoons. + + +(_b._) _Sublimation_ is that process by which we convert a solid +substance into vapor by means of a strong heat. These vapors are +condensed by refrigeration into the solid form. It may be termed a +distillation of a solid substance. Sublimation is of great consequence +in the detection of many substances; for instance, arsenic, antimony, +mercury, etc. + +The apparatus used for the purposes of sublimation consist of glass +tubes closed at one end. + + +(_c._) _Fusion._--Many substances when exposed to a certain degree of +heat lose their solid form, and are converted into a liquid. Those +substances which do not become converted into the liquid state by +heat, are said to be infusible. It is a convenient classification to +arrange substances into those which are fusible with difficulty, and +those which are easily fusible. Very often we resort to fusion for the +purpose of decomposing a substance, or to cause it to enter into +other combinations, by which means it is the more readily detected. If +insoluble substances are fused with others more fusible (reagents) for +the purpose of causing a combination which is soluble in water and +acids, the operation is termed _unclosing_. These substances are +particularly the silicates and the sulphates of the alkaline earths. +The usual reagents resorted to for this purpose are carbonate of soda +(NaO, CO^{2}), carbonate of potash (KO, CO^{2}), or still better, a +mixture of the two in equal parts. In some cases we use the hydrate of +barytes (BaO, HO) and the bisulphate of potash (KO, 2SO^{3}). The +platinum spoon is generally used for this manipulation. + +Substances are exposed to fusion for the purpose of getting a new +combination which has such distinctive characteristics that we can +class it under a certain group; or for the purpose of ascertaining at +once what the substance may be. The reagents used for this purpose are +borax (NaO, 2BrO^{3}) and the microcosmic salt (NaO, NH^{4}O, PO^{5}, +HO). Charcoal and the platinum wire are used as supports for this kind +of operation. + + +(_d._) _Oxidation._--The chemical combination of any substance with +oxygen is termed _oxidation_, and the products are termed _oxides_. As +these oxides have qualities differing from those which are +non-oxidized, it therefore frequently becomes necessary to convert +substances into oxides; or, if they are such, of a lower degree, to +convert them into a higher degree of oxidation. These different states +of oxidation frequently present characteristic marks of identity +sufficient to enable us to draw conclusions in relation to the +substance under examination. For instance, the oxidation of manganese, +of arsenic, etc. The conditions necessary for oxidation, are high +temperature and the free admission of air to the substance. + +If the oxidation is effected through the addition of a substance +containing oxygen (for instance, the nitrate or chlorate of potash) +and the heating is accompanied by a lively deflagration and crackling +noise, it is termed _detonation_. By this process we frequently +effect the oxidation of a substance, and thus we prove the presence or +the absence of a certain class of substances. For instance, if we +detonate (as it is termed by the German chemists) the sulphide of +antimony, or the sulphide of arsenic with nitrate of potash, we get +the nitrate of antimony, or the nitrate of arsenic. The salts of +nitric or chloric acid are determined by fusing them with the cyanide +of potassium, because the salts of these acids detonate. + + +(_e._) _Reduction._--If we deprive an oxidized substance of its +oxygen, we term the process _reduction_. This is effected by fusing +the substance under examination with another which possesses a greater +affinity for oxygen. The agents used for reduction are hydrogen, +charcoal, soda, cyanide of potassium, etc. Substances generally, when +in the unoxidized state, have such characteristic qualities, that they +cannot very readily be mistaken for others. For this reason, reduction +is a very excellent expedient for the purpose of discerning and +classifying many substances. + + +B. UTENSILS. + +We shall give here a brief description of the most necessary apparatus +used for analysis in the dry way, and of their use. + +_The Blowpipe_ is a small instrument, made generally out of brass, +silver, or German silver, and was principally used in earlier times +for the purpose of soldering small pieces of metals together. It is +generally made in the form of a tube, bent at a right angle, but +without a sharp corner. The largest one is about seven inches long, +and the smallest about two inches. The latter one terminates with a +small point, with a small orifice. The first use of the blowpipe that +we have recorded is that of a Swedish mining officer, who used it in +the year 1738 for chemical purposes, but we have the most meagre +accounts of his operations. In 1758 another Swedish mining officer, by +the name of Cronstedt, published his "Use of the Blowpipe in +Chemistry and Mineralogy," translated into English, in 1770, by Van +Engestroem. Bergman extended its use, and after him Ghan and the +venerable Berzelius (1821). The blowpipe most generally used in +chemical examinations is composed of the following parts: (_Fig._ 1.) +A is a little reservoir made air-tight by grinding the part B into it. +This reservoir serves the purpose of retaining the moisture with which +the air from the mouth is charged. A small conical tube is fitted to +this reservoir. This tube terminates in a fine orifice. As this small +point is liable to get clogged up with soot, etc., it is better that +it should be made of platinum, so that it may be ignited. Two of these +platinum tubes should be supplied, differing in the size of the +orifice, by which a stronger or lighter current of flame may be +projected from it. Metals, such as brass or German silver, are very +liable to become dirty through oxidation, and when placed between the +lips are liable to impart a disagreeable taste. To avoid this, the top +of the tube must be supplied with a mouthpiece of ivory or horn C. The +blowpipe here represented is the one used by Ghan, and approved by +Berzelius. The trumpet mouthpiece was adopted by Plattner; it is +pressed upon the lips while blowing, which is less tiresome than +holding the mouthpiece between the lips, although many prefer the +latter mode. + +[Illustration: Fig. 1] + +Dr. Black's blowpipe is as good an instrument and cheaper. It +consists of two tubes, soldered at a right angle; the larger one, into +which the air is blown, is of sufficient capacity to serve as a +reservoir. + +A chemist can, with a blowpipe and a piece of charcoal, determine many +substances without any reagents, thus enabling him, even when +travelling, to make useful investigations with means which are always +at his disposal. There are pocket blowpipes as portable as a pencil +case, such as Wollaston's and Mitscherlich's; these are objectionable +for continued use as their construction requires the use of a metallic +mouthpiece. Mr. Casamajor, of New York, has made one lately which has +an ivory mouthpiece, and which, when in use, is like Dr. Black's. + +[Illustration: Fig. 2] + +The length of the blowpipe is generally seven or eight inches, but +this depends very much upon the visual angle of the operators. A +short-sighted person, of course, would require an instrument of less +length than would suit a far-sighted person. + +The purpose required of the blowpipe is to introduce a fine current of +air into the flame of a candle or lamp, by which a higher degree of +heat is induced, and consequently combustion is more rapidly +accomplished. + +By inspecting the flame of a candle burning under usual circumstances, +we perceive at the bottom of the flame a portion which is of a light +blue color (_a b_), _Fig._ 2, which gradually diminishes in size +as it recedes from the wick, and disappears when it reaches the +perpendicular side of the flame. In the midst of the flame there is a +dark nucleus with a conical form (_c_). This is enveloped by the +illuminating portion of the flame (_d_). At the exterior edge of the +part _d_ we perceive a thin, scarcely visible veil, _a, e, e_, which +is broader near the apex of the flame. The action of the burning +candle may be thus explained. The radiant heat from the flame melts +the tallow or wax, which then passes up into the texture of the wick +by capillary attraction until it reaches the glowing wick, where the +heat decomposes the combustible matter into carbonated hydrogen +(C^{4}H^{4}), and into carbonic oxide (CO). + +While these gases are rising in hot condition, the air comes in +contact with them and effects their combustion. The dark portion, _c_, +of the flame is where the carbon and gases have not a sufficiency of +air for their thorough combustion; but gradually they become mixed +with air, although not then sufficient for complete combustion. The +hydrogen is first oxidized or burnt, and then the carbon is attacked +by the air, although particles of carbon are separated, and it is +these, in a state of intense ignition, which produce the illumination. +By bringing any oxidizable substance into this portion of the flame, +it oxidizes very quickly in consequence of the high temperature and +the free access of air. For that reason this part of the flame is +termed the oxidizing flame, while the illuminating portion, by its +tendency to abstract oxygen for the purpose of complete combustion, +easily reduces oxidated substances brought into it, and it is, +therefore, called the flame of reduction. In the oxidizing flame, on +the contrary, all the carbon which exists in the interior of the flame +is oxidized into carbonic acid (CO^{2}) and carbonic oxide (CO), while +the blue color of the cone of the flame is caused by the complete +combustion of the carbonic oxide. These two portions of the flame--the +oxidizing and the reducing--are the principal agents of blowpipe +analysis. + +If we introduce a fine current of air into a flame, we notice the +following: The air strikes first the dark nucleus, and forcing the +gases beyond it, mixes with them, by which oxygen is mingled freely +with them. This effects the complete combustion of the gases at a +certain distance from the point of the blowpipe. At this place the +flame has the highest temperature, forming there the point of a blue +cone. The illuminated or reducing portion of the flame is enveloped +outside and inside by a very hot flame, whereby its own temperature is +so much increased that in this reduction-flame many substances will +undergo fusion which would prove perfectly refractory in a common +flame. The exterior scarcely visible part loses its form, is +diminished, and pressed more to a point, by which its heating power is +greatly increased. + +_The Blast of Air._--By using the blowpipe for chemical purposes, the +effect intended to be produced is an uninterrupted steady stream of +air for many minutes together, if necessary, without an instant's +cessation. Therefore, the blowing can only be effected with the +muscles of the cheeks, and not by the exertion of the lungs. It is +only by this means that a steady constant stream of air can be kept +up, while the lungs will not be injured by the deprival of air. The +details of the proper manner of using the blowpipe are really more +difficult to describe than to acquire by practice; therefore the pupil +is requested to apply himself at once to its practice, by which he +will soon learn to produce a steady current of air, and to distinguish +the different flames from each other. We would simply say that the +tongue must be applied to the roof of the mouth, so as to interrupt +the communication between the passage of the nostrils and the mouth. +The operator now fills his mouth with air, which is to be passed +through the pipe by compressing the muscles of the cheeks, while he +breathes through the nostrils, and uses the palate as a valve. When +the mouth becomes nearly empty, it is replenished by the lungs in an +instant, while the tongue is momentarily withdrawn from the roof of +the mouth. The stream of air can be continued for a long time, without +the least fatigue or injury to the lungs. The easiest way for the +student to accustom himself to the use of the blowpipe, is first to +learn to fill the mouth with air, and while the lips are kept firmly +closed to breathe freely through the nostrils. Having effected this +much, he may introduce the mouthpiece of the blowpipe between his +lips. By inflating the cheeks, and breathing through the nostrils, he +will soon learn to use the instrument without the least fatigue. The +air is forced through the tube against the flame by the action of the +muscles of the cheeks, while he continues to breathe without +interruption through the nostrils. Having become acquainted with this +process, it only requires some practice to produce a steady jet of +flame. A defect in the nature of the combustible used, as bad oil, +such as fish oil, or oil thickened by long standing or by dirt, dirty +cotton wick, or an untrimmed one, or a dirty wickholder, or a want of +steadiness of the hand that holds the blowpipe, will prevent a steady +jet of flame. But frequently the fault lies in the orifice of the jet, +or too small a hole, or its partial stoppage by dirt, which will +prevent a steady jet of air, and lead to difficulty. With a good +blowpipe the air projects the entire flame, forming a horizontal, blue +cone of flame, which converges to a point at about an inch from the +wick, with a larger, longer, and more luminous flame enveloping it, +and terminating to a point beyond that of the blue flame. + +To produce an efficient flame of oxidation, put the point of the +blowpipe into the flame about one third the diameter of the wick, and +about one twelfth of an inch above it. This, however, depends upon +the size of the flame used. Blow strong enough to keep the flame +straight and horizontal, using the largest orifice for the purpose. +Upon examining the flame thus produced, we will observe a long, blue +flame, _a b_, Fig. 3, which letters correspond with the same letters +in Fig. 2. But this flame has changed its form, and contains all the +combustible gases. It forms now a thin, blue cone, which converges to +a point about an inch from the wick. This point of the flame possesses +the highest intensity of temperature, for there the combustion of the +gases is the most complete. In the original flame, the hottest part +forms the external envelope, but here it is compressed more into a +point, forming the cone of the blue flame, and likewise an envelope of +flame surrounding the blue one, extending beyond it from _a_ to _c_, +and presenting a light bluish or brownish color. The external flame +has the highest temperature at _d_, but this decreases from _d_ to +_c_. + +[Illustration: Fig. 3] + +If there is a very high temperature, the oxidation is not effected so +readily in many cases, unless the substance is removed a little from +the flame; but if the heat be not too high, it is readily oxidized in +the flame, or near its cone. If the current of air is blown too +freely or violently into the flame, more air is forced there than is +sufficient to consume the gases. This superfluous air only acts +detrimentally, by cooling the flame. + +In general the operation proceeds best when the substance is kept at a +dull red heat. The blue cone must be kept free from straggling rays of +the yellow or reduction flame. If the analysis be effected on +charcoal, the blast should not be too strong, as a part of the coal +would be converted into carbonic oxide, which would act +antagonistically to the oxidation. The oxidation flame requires a +steady current of air, for the purpose of keeping the blue cone +constantly of the same length. For the purpose of acquiring practice, +the following may be done: Melt a little molybdenic acid with some +borax, upon a platinum wire, about the sixteenth of an inch from the +point of the blue cone. In the pure oxidation flame, a clear yellowish +glass is formed; but as soon as the reduction flame reaches it, or the +point of the blue cone touches it, the color of the bead changes to a +brown, which, finally, after a little longer blowing, becomes quite +dark, and loses its transparency. The cause of this is, that the +molybdenic acid is very easily reduced to a lower degree of oxidation, +or to the oxide of molybdenum. The flame of oxidation will again +convert this oxide into the acid, and this conversion is a good test +of the progress of the student in the use of the blowpipe. In cases +where we have to separate a more oxidizable substance from a less one, +we use with success the blue cone, particularly if we wish to +determine whether a substance has the quality, when submitted to heat +in the blue cone, of coloring the external flame. + +A good _reduction_ flame can be obtained by the use of a small orifice +at the point of the blowpipe. In order to produce such a flame, hold +the point of the blowpipe higher above the wick, while the nozzle must +not enter the flame so far as in the production of the oxidation +flame. The point of the blowpipe should only touch the flame, while +the current of air blown into it must be stronger than into the +oxidation flame. If we project a stream, in the manner mentioned, into +the flame, from the smaller side of the wick to the middle, we shall +perceive the flame changed to a long, narrow, luminous cone, _a b_, +Fig. 4, the end _a_ of which is enveloped by the same dimly visible +blueish colored portion of the flame _a, c_, which we perceive in the +original flame, with its point at _c_. The portion close above the +wick, presenting the dull appearance, is occasioned by the rising +gases which have not supplied to them enough oxygen to consume them +entirely. The hydrogen is consumed, while the carbon is separated in a +state of bright ignition, and forms the internal flame. + +[Illustration: Fig. 4] + +Directly above the wick, the combustion of the gases is least +complete, and forms there likewise, as is the case in the free flame, +a dark blue nucleus _d_. + +If the oxide of a metal is brought into the luminous portion of the +flame produced as above, so that the flame envelopes the substance +perfectly, the access of air is prevented. The partially consumed +gases have now a strong affinity for oxygen, under the influence of +the intense heat of that part of the flame. The substance is thus +deprived of a part, or the whole, of its oxygen, and becomes _reduced_ +according to the strength of the affinity which the substance itself +has for oxygen. If the reduction of a substance is undertaken on +platinum, by fusion with a flux, and if the oxide is difficult to +reduce, the reduction will be completely effected only in the luminous +part of the flame. But if a substance be reduced on charcoal, the +reduction will take place in the blue part of the flame, as long as +the access of air is cut off; but it is the luminous part of the flame +which really possesses the greatest reducing power. + +The following should be observed in order to procure a good reduction +flame: + + The wick should not be too long, that it may make a smoke, nor + too short, otherwise the flame will be too small to produce a + heat strong enough for reduction. + + The wick must be free from all loose threads, and from + charcoal. + + The blast should be continued for a considerable time without + intermission, otherwise reduction cannot be effected. + +For the purpose of acquiring practice, the student may fuse the oxide +of manganese with borax, upon a platinum wire, in the oxidation flame, +when a violet-red glass will be obtained; or if too much of the oxide +be used, a glass of a dark color and opaque will be obtained. By +submitting this glass to the reduction flame, it will become colorless +in correspondence to the perfection with which the flame is produced. +Or a piece of tin may be fused upon charcoal, and kept in that state +for a considerable time, while it presents the appearance of a bright +metal on the surface. This will require dexterity in the operator; +for, if the oxidation flame should chance to touch the bright metal +only for a moment, it is coated with an infusible oxide. + + +COMBUSTION.--Any flame of sufficient size can be used for blowpipe +operations. It may be either the flame of a candle of tallow or wax, +or the flame of a lamp. The flame of a wax candle, or of an oil lamp +is most generally used. Sometimes a lamp is used filled with a +solution of spirits of turpentine in strong alcohol. If a candle is +used, it is well to cut the wick off short, and to bend the wick a +little toward the substance experimented upon. But candles are not the +best for blowpipe operations, as the radiant heat, reflecting from the +substance upon the wax or tallow, will cause it to melt and run down +the side of the candle; while again, candles do not give heat enough. +The lamp is much the most desirable. The subjoined figure, from +Berzelius, is perhaps the best form of lamp. It is made of japanned +tin-plate, about four inches in length, and has the form and +arrangement represented in Fig. 5. K is the lamp, fastened on the +stand, S, by a screw, C, and is movable upwards or downwards, as +represented in the figure. The posterior end of the lamp may be about +one inch square, and at its anterior end, E, about three-quarters of +an inch square. The under side of this box may be round, as seen in +the figure. The oil is poured into the orifice, A, which has a cap +screwed over it. C' is a wickholder for a flat lamp-wick. _a_ is a +socket containing the wick, which, when not in use, is secured from +dirt by the cap. The figures B and _a'_ give the forms of the cap and +socket. The best combustible for this lamp is the refined rape-seed +oil, or pure sweet oil. When this lamp is in use, there must be no +loose threads, or no charcoal on the wick, or these will produce a +smoky flame. The wick, likewise, should not be pulled up too high, as +the same smoky flame would be produced. + +[Illustration: Fig. 5] + + +THE SPIRIT-LAMP.--This is a short, strong glass lamp, with a cap, B, +Fig. 6, fitted to it by grinding, to prevent the evaporation of the +alcohol. The neck _a_ contains a tube C, made of silver, or of tin +plate, and which contains the wick. Brass would not answer so well +for this tube, as the spirits would oxidize it, and thus impart color +to the flame. The wickholder must cover the edge of the neck, but not +fit tight within the tube, otherwise, by its expansion, it will break +the glass. It is not necessary that alcohol, very highly rectified, +should be burnt in this lamp, although if too much diluted with water, +enough heat will not be given out. Alcohol of specific gravity 0.84 to +0.86 is the best. + +[Illustration: Fig. 6] + +This lamp is generally resorted to by blowpipe analysts, for the +purpose of experiments in glass apparatus, as the oily combustibles +will coat the glass with soot. Some substances, when exposed to the +dark part of the flame, become reduced and, _in statu nascendi_, +evaporated; but by passing through the external part of the flame, +they become oxidized again, and impart a color to the flame. The +spirit flame is the most efficient one for the examination of +substances the nature of which we wish to ascertain through color +imparted to the flame, as that of the spirit-lamp being colorless, is, +consequently, most easily and thoroughly recognized by the slightest +tinge imparted to it. + +It is necessary that in operating with such minute quantities of +substances as are used in blowpipe analysis, that they should have +some appropriate support. In order that no false results may ensue, it +is necessary that the supports should be of such a nature that they +will not form a chemical combination with the substance while it is +exposed to fusion or ignition. Appropriate supports for the different +blowpipe experiments are charcoal, platinum instruments, and glass +tubes. + +(_a._) _Charcoal._--The value of charcoal as a support may be stated +as follows: + + 1. The charcoal is infusible, and being a poor conductor of + heat, a substance can be exposed to a higher degree of heat + upon it than upon any other substance. + + 2. It is very porous, and therefore allows easily fusible + substances (such as alkalies and fluxes) to pass into it, + while other substances less fusible, such as metals, to remain + unabsorbed. + + 3. It has likewise a great reducing power. + +The best kind of charcoal is that of pinewood, linden, willow, or +alderwood, or any other soft wood. Coal from the firwood sparkles too +freely, while that of the hard woods contains too much iron in its +ashes. Smooth pieces, free from bark and knots, should be selected. It +should be thoroughly burnt, and the annual rings or growths should be +as close together as possible. + +If the charcoal is in masses, it should be sawed into pieces about six +inches in length by about two inches broad, but so that the +year-growths run perpendicular to the broadest side, as the other +sides, by their unequal structure, burn unevenly. + +That the substance under examination may not be carried off by the +blast, small conical concavities should be cut in the broad side of +the charcoal, between the year-growths, with a conical tube of tin +plate about two or three inches long, and one quarter of an inch at +one end, and half an inch at the other. These edges are made sharp +with a file. The widest end of this charcoal borer is used for the +purpose of making cavities for cupellation. + +In places where the proper kind of charcoal is difficult to procure, +it is economical to cut common charcoal into pieces about an inch +broad, and the third of an inch thick. In each of these little pieces +small cavities should be cut with the small end of the borer. When +these pieces of charcoal are required for use, they must be fastened +to a narrow slip of tin plate, one end of which is bent into the form +of a hook, under which the plate of charcoal is pushed. + +In general, we use the charcoal support where we wish to reduce +metallic oxides, to prevent oxidation, or to test the fusibility of a +substance. There is another point to which we would direct the +student. Those metals which are volatile in the reduction flame, +appear as oxides in the oxidation flame. These oxides make sublimates +upon the charcoal close in the vicinity of the substance, or where it +rested, and by their peculiar color indicate pretty correctly the +species of minerals experimented upon. + +(_b._) _Platinum Supports._--The metal platinum is infusible in the +blowpipe flame, and is such a poor conductor of heat that a strip of +it may be held close to that portion of it which is red hot without +the least inconvenience to the fingers. It is necessary that the +student should be cognizant of those substances which would not be +appropriate to experiment upon if placed on platinum. Metals should +not be treated upon platinum apparatus, nor should the easily +reducible oxides, sulphides, nor chlorides, as these substances will +combine with the platinum, and thus render it unfit for further use in +analysis. + +(_c._) _Platinum Wire._--As the color of the flame cannot be well +discerned when the substance is supported upon charcoal, in +consequence of the latter furnishing false colors, by its own +reflection, to the substances under examination, we use platinum wire +for that purpose, when we wish to examine those substances which give +indications by the peculiar color which they impart to fluxes. The +wire should be about as thick as No. 16 or 18 wire, or about 0.4 +millimetre, and cut into pieces about from two and a half to three +inches in length. The end of each piece is crooked. In order that +these pieces should remain clear of dirt, and ready for use, they +should be kept in a glass of water. To use them, we dip the wetted +hooked end into the powdered flux (borax or microcosmic salt) some of +which will adhere, when we fuse it in the flame of the blowpipe to a +bead. This bead hanging in the hook, must be clear and colorless. +Should there not adhere a sufficient quantity of the flux in the first +trial to form a bead sufficiently large, the hook must be dipped a +second time in the flux and again submitted to the blowpipe flame. To +fix the substance to be examined to the bead, it is necessary, while +the latter is hot, to dip it in the powdered substance. If the hook is +cold, we moisten the powder a little, and then dip the hook into it, +and then expose it to the oxidation flame, by keeping it exposed to a +regular blast until the substance and the flux are fused together, and +no further alteration is produced by the flame. + +The platinum wire can be used except where reduction to the metallic +state is required. Every reduction and oxidation experiment, if the +results are to be known by the color of the fluxes, should be effected +upon platinum wire. At the termination of the experiment or +investigation, if it be one, to, clean the wire, place it in water, +which will dissolve the bead. + +(_d._) _Platinum Foil._--For the heating or fusing of a substance, +whereby its reduction would be avoided, we use platinum foil as a +support. This foil should be of the thickness of good writing paper, +and from two and a half to three inches long, by about half an inch +broad, and as even and smooth as possible. If it should become injured +by long use, cut the injured end off, and if it should prove too short +to be held with the fingers, a pair of forceps may be used to grasp +it, or it may be placed on a piece of charcoal. + +(_e._) _Platinum Spoon._--When we require to fuse substances with the +acid sulphate of potash, or to oxidize them by detonation with nitrate +of potash, whereby we wish to preserve the oxide produced, we +generally use a little spoon of platinum, about from nine to fifteen +millimetres[1] in diameter, and shaped as represented in Fig. 7. The +handle of this spoon is likewise of platinum, and should fit into a +piece of cork, or be held with the forceps. + + [1] The French millimetre is about the twenty-fifth part of an + English inch. + +[Illustration: Fig. 7.] + +(_f._) _Platinum Forceps or Tongs._--We frequently are necessitated to +examine small splinters of metals or minerals directly in the blowpipe +flame. These pieces of metallic substances are held with the forceps +or tongs represented as in Fig. 8, where _ac_ is formed of steel, and +_aa_ are platinum bars inserted between the steel plates. At _bb_ are +knobs which by pressure so separate the platinum bars _aa_, that any +small substance can be inserted between them. + +[Illustration: Fig. 8.] + +(_g._) _Iron Spoons._--For a preliminary examination iron spoons are +desirable. They may be made of sheet iron, about one-third of an inch +in diameter, and are very useful in many examinations where the use of +platinum would not be desirable. + +(_h._) _Glass Tubes._--For the separation and recognition of volatile +substances before the blowpipe flame, we use glass tubes. These should +be about one-eighth of an inch in diameter, and cut into pieces about +five or six inches in length. These tubes should have both ends open. + +Tubes are of great value in the examination of volatile substances +which require oxidizing or roasting, and heating with free access of +air. Also to ascertain whether a substance under examination will +sublimate volatile matter of a certain appearance. Such substances are +selenium, sulphur, arsenic, antimony, and tellurium. These substances +condense on a cool part of the tube, and they present characteristic +appearances, or they may be recognized by their peculiar smell. These +tubes must be made of the best kind of glass, white and difficult of +fusion, and entirely free from lead. The substance to be examined must +be put in the tube near one end, and exposed to the flame of the +blowpipe. The end containing the substance must be held lower than the +other end, and must be moved a little over the spirit-lamp before a +draught of air is produced through the tube. It is a good plan to have +a number of these tubes on hand. After having used a tube we cut off +that end of it which contained the substance, with a file, and clean +it from the sublimate, either by heating it over the spirit-lamp, or +with a piece of paper wound around a wire. It sometimes happens that +the substance falls out of the tube before it becomes sufficiently +melted to adhere to the glass. To obviate this, we bend the tube not +far from the end, at an obtuse angle, and place the substance in the +angle, whereby the tube may be lowered as much as necessary. Fig. 9 +will give the student a comprehension of the processes described, and +of the manner of bending the tubes. + +[Illustration: Fig. 9.] + +(_i._) _Glass Tubes closed at one End._--If we wish to expose volatile +substances to heat, with the exclusion of air as much as possible, or +to ascertain the contents of water, or other volatile fluids, or for +the purpose of heating substances which will decrepitate, we use glass +tubes closed at one end. These tubes must be about one-eighth of an +inch wide, and from two to three inches in length. They should be made +of white glass, difficult of fusion, and free from lead. They should +be closed at one end, as figured in the margin, Fig. 10. + +[Illustration: Fig. 10.] + +When a substance is to be examined for the purpose of ascertaining +whether it contains combustible matter, as sulphur or arsenic, and +where we wish to avoid oxidation, we use these tubes without extending +the closed end, in order that there may be as little air admitted as +possible, as is represented in tube B. But when a substance to be +examined is to be tested for water, or other incombustible volatile +matters, we employ tubes with little bulbs blown at one end, such as +represented at tube A. Here there is room for a circulation of air at +the bottom of the tube, by which the volatile matter rises more +easily. In some cases, it is necessary to draw the closed end out to a +fine point, as in the tubes C and D. Either one or the other of these +tubes is employed, depending upon the nature of the substance used. +The sublimates condense at the upper part of the tube _a_, and can be +there examined and recognized. These tubes, before being used, must be +thoroughly dried and cleaned. In experimenting with them, they should +not be exposed at once to the hottest part of the flame, but should be +submitted to the heat gradually. If the substance is of such a nature +that it will sublime at a low heat, the tube should be held more +horizontal, while a higher heat is attained by bringing the tube to a +more vertical position. + + +VARIOUS APPARATUS NECESSARY. + +_Edulcorator or Washing Bottle._--Take a glass bottle of the capacity +of about twelve ounces, and close the mouth of it very tight with a +cork, through which a short glass tube is fitted airtight. The +external end of this tube is drawn out to a point, with a very fine +orifice. The bottle should be filled about half full of water. By +blowing air into the bottle through the tube, and then turning it +downwards, the compressed air will expel a fine stream of water +through the fine orifice with considerable force. We use this washing +bottle, Fig. 11, for the purpose of rinsing the small particles of +coal from the reduced metals. + +[Illustration: Fig. 11.] + +_Agate Mortar and Pestle._--This mortar is used for the purpose of +pulverizing hard substances, and for mixing fluxes. As this mortar +will not yield to abrasion, there is no danger of any foreign matter +becoming mixed with the substance pulverized in it. It should be +cleaned after use with pumice stone. Steel mortars are very useful for +the pulverization of hard bodies; but for all those substances which +require great care in their analysis, and which can be obtained in +very minute quantity, the agate mortar alone should be used. + +A _hammer_ made of steel is necessary. This should have the edge +square. + +A small _anvil_, polished on the surface, is also required. It is +frequently used to test the malleability of metals. + +A _knife_, for the purpose of ascertaining the hardness of minerals. + +The student should also be provided with several three-edged files, +and likewise with some flat ones. + +A _microscope_, an instrument with two lenses, or with such a +combination of lenses, that they may be used double or single, is +frequently necessary for the examination of blowpipe experiments, or +the reaction of the fluxes. Common lenses, howsoever cheap they may +be, are certainly not recommended. A microscope with achromatic lenses +can now be purchased so cheap that there is no longer any necessity of +procuring one with the common lens. Besides, there is no reliability +whatever to be placed in the revelations of the common lens; while on +the contrary, the deceptive appearances which minute objects assume +beneath such lenses are more injurious than otherwise. A small cheap +set of magnifying glasses are all that is required for the purpose of +blowpipe analysis, Fig. 12. + +[Illustration: Fig. 12.] + +A small _magnet_ should be kept on hand, for the purpose of testing +reduced metals. + +_Nippers_, for the purpose of breaking off pieces of minerals for +analysis, without injuring the entire piece, are indispensable, Fig +13. + +[Illustration: Fig. 13.] + +A pair of _scissors_ is required to trim the wick of the and for the +trimming of the edge of platinum foil. + +A small _spatula_ should be kept for the purpose of mixing substances +with fluxes. + + + + +THE REAGENTS. + + +Those substances which possess the property of acting upon other +substances, in such a characteristic manner that they can be +recognized, either by their color, or by their effervescence, or by +the peculiar precipitation produced, are termed _reagents_. The +phenomena thus produced is termed _reaction_. We use those reagents, +or _tests_, for the purpose of ascertaining the presence or the +absence of certain substances, through the peculiar phenomena produced +when brought in contact with them. + +The number of reagents employed in blowpipe analysis is not great, and +therefore we shall here give a brief description of their preparation +and use. It is indispensably necessary that they should be chemically +pure, as every admixture of a foreign substance would only produce a +false result. Some of them have a strong affinity for water, or are +deliquescent, and consequently absorb it greedily from the air. These +must be kept in glass bottles, with glass stoppers, fitted air-tight +by grinding. + + +A. REAGENTS OF GENERAL USE. + + +1. _Carbonate of Soda._--(NaO, CO^{2}) Wash the bicarbonate of soda +(NaO, 2CO^{2}) upon a filter, with cold water, until the filtrate +ceases to give, after neutralization with diluted nitric acid +(NO^{5}), a precipitate with nitrate of baryta, (BaO, NO^{5}), or +nitrate of silver, (AgO, NO^{5}). That left upon the filter we make +red hot in a platinum, silver, or porcelain dish. One atom of carbonic +acid is expelled, and the residue is carbonate of soda. + +A solution of soda must not be changed by the addition of sulphide of +ammonium. And when neutralized with hydrochloric acid, and evaporated +to dryness, and again dissolved in water, there must be no residue +left. + +Carbonate of soda is an excellent agent in reduction, in consequence +of its easy fusibility, whereby it causes the close contact of the +oxides with the charcoal support, so that the blowpipe flame can reach +every part of the substance under examination. + +For the decomposition and determination of insoluble substances, +particularly the silicates, carbonate of soda is indispensable. But +for the latter purpose, we use with advantage a mixture of ten parts +of soda and thirteen parts of dry carbonate of potash, which mixture +fuses more easily than the carbonate of soda alone. + + +2. _Hydrate of Baryta_ (BaO, HO).--This salt is used sometimes for the +detection of alkalies in silicates. Mix one part of the substance with +about four parts of the hydrate of baryta, and expose it to the +blowpipe flame. The hydrate of baryta combines with the silicic acid, +and forms the super-basic silicate of baryta, while the oxides become +free. The fused mass must be dissolved in hydrochloric acid, which +converts the oxides into chlorides. Evaporate to dryness, and dissolve +the residue in water. The silicic acid remains insoluble. + +The hydrate of baryta is prepared by mixing six parts of finely +powdered heavy-spar (BaO, SO_{3}) with one part of charcoal and one +and a half parts of wheat flour, and exposing this mixture in a +Hessian crucible with a cover to a strong and continuous red heat. The +cooled chocolate-brown mass must be boiled with twenty parts of water, +and, while boiling, there must be added the oxide of copper in +sufficient quantity, or until the liquid will not impart a black color +to a solution of acetate of lead (PbO, [=]A). The liquid must be +filtered while hot, and as it cools the hydrate of baryta appears in +crystals. These crystals must be washed with a little cold water, and +then heated at a low temperature in a porcelain dish until the crystal +water is expelled. The hydrate of baryta melts by a low red heat +without losing its water of hydration. + + +3. _Bisulphate of Potassa_ (KO, 2SO^{3}).--At a red heat the half of +the sulphuric acid of this salt becomes free, and thus separates and +expels volatile substances, by which we can recognize lithium, boracic +acid, nitric acid, fluoric acid, bromine, iodine, chlorine; or it +decomposes and reveals some other compounds, as, for instance, the +salts of the titanic, tantalic and tungstic acids. The bisulphate of +potash is also used for the purpose of converting a substance into +sulphate, or to free it at once from certain constituents. These +sulphates are dissolved in water, by which we are enabled to effect +the separation of its various constituents. + +PREPARATION.--Two parts of coarsely powdered sulphate of potash are +placed in a porcelain crucible, and one part of pure sulphuric acid is +poured over it. Expose this to heat over the spirit-lamp, until the +whole becomes a clear liquid. The cooled mass must be of a pure white +color, and may be got out of the crucible by inverting it. It must be +kept in a fine powder. + + +4. _Oxalate of Potassa_ (KO, [=]O).--Dissolve bioxalate of potash in +water, and neutralize with carbonate of potash. Evaporate the solution +at a low heat to dryness, stirring constantly towards the close of the +operation. The dry residue is to be kept in the form of a powder. + +The oxalate of potash, at a low red heat, eliminates a considerable +quantity of carbonic oxide, which, having a strong affinity for +oxygen, with which it forms carbonic acid, it is therefore a powerful +agent of reduction. It is in many cases preferable to carbonate of +soda. + + +5. _Cyanide of Potassium_ (Cy, K).--In the dry method of analysis, +this salt is one of the most efficient agents for the reduction of +metallic oxides. It separates not only the metals from their oxygen +compounds, but likewise from their sulphur compounds, while it is +converted through the action of the oxygen into carbonate of potash, +or, in the latter case, combines with the sulphur and forms the +sulphureted cyanide of potassium. This separation is facilitated by +its easy fusibility. But in many cases it melts too freely, and +therefore it is better to mix it, for blowpipe analysis, with an equal +quantity of soda. This mixture has great powers of reduction, and it +is easily absorbed by the charcoal, while the globules of reduced +metal are visible in the greatest purity. + +PREPARATION.--Deprive the ferrocyanide of potassium (2KCy + FeCy) of +its water by heating it over the spirit-lamp in a porcelain dish. Mix +eight parts of this anhydrous salt with three parts of dry carbonate +of potash, and fuse the mixture by a low red heat in a Hessian, or +still better, in an iron crucible with a cover, until the mass flows +quiet and clear, and a sample taken up with an iron spatula appears +perfectly white. Pour the clear mass out into a china or porcelain +dish or an iron plate, but with caution that the fine iron particles +which have settled to the bottom, do not mix with it. The white fused +mass must be powdered, and kept from the air. The cyanide of potassium +thus prepared, contains some of the cyanate of potassa, but the +admixture does not deteriorate it for blowpipe use. It must be +perfectly white, free from iron, charcoal, and sulphide of potassium. +The solution of it in water must give a white precipitate with a +solution of lead, and when neutralized with hydrochloric acid, and +evaporated to dryness, it must not give an insoluble residue by +dissolving it again in water. + + +6. _Nitrate of Potassa, Saltpetre_ (KO, NO^{5}).--Saturate boiling +water with commercial saltpetre, filter while hot in a beaker glass, +which is to be placed in cold water, and stir while the solution is +cooling. The greater part of the saltpetre will crystallize in very +fine crystals. Place these crystals upon a filter, and wash them with +a little cold water, until a solution of nitrate of silver ceases to +exhibit any reaction upon the filtrate. These crystals must be dried +and powdered. + +Saltpetre, when heated with substances easy of oxidation, yields its +oxygen quite readily, and is, therefore, a powerful means of +oxidation. In blowpipe analysis, we use it particularly to convert +sulphides (as those of arsenic, antimony, &c.) into oxides and acids. +We furthermore use saltpetre for the purpose of producing a complete +oxidation of small quantities of metallic oxides, which oxidize with +difficulty in the oxidation flame, so that the color of the bead, in +its highest state of oxidation, shall be visible, as for instance, +manganese dissolved in the microcosmic salt. + + +7. _Biborate of soda, borax_--(NaO + 2BO^{3}).--Commercial borax is +seldom pure enough for a reagent. A solution of borax must not give a +precipitate with carbonate of potassa; or, after the addition of +dilute nitric acid, it must remain clear upon the addition of nitrate +of silver, or nitrate of baryta. Or a small piece of the dry salt, +fused upon a platinum wire, must give a clear and uncolored glass, as +well in the oxidation flame as in the reduction flame. If these tests +indicate a foreign admixture, the borax must be purified by +re-crystallization. These crystals are washed upon a filter, dried, +and heated, to expel the crystal water, or until the mass ceases to +swell up, and it is reduced to powder. + +Boracic acid is incombustible, and has a strong affinity for oxides +when fused with them; therefore, it not only directly combines with +oxides, but it expels, by fusion, all other volatile acids from their +salts. Furthermore, boracic acid promotes the oxidation of metals and +sulphur, and induces haloid compounds, in the oxidation flame, to +combine with the rising oxides. Borates thus made, melt generally by +themselves; but admixed with borate of soda, they fuse much more +readily, give a clear bead. Borax acts either as a flux, or through +the formation of double salts. + +In borax, we have the action of free boracic acid, as well as borate +of soda, and for that reason it is an excellent reagent for blowpipe +analysis. + +All experiments in which borax is employed should be effected upon +platinum wire. The hook of the wire should be heated red hot, and then +dipped into the powdered borax. This should be exposed to the +oxidation flame, when it will be fused to a bead, which adheres to the +hook. This should be then dipped into the powdered substance, which +will adhere to it if it is hot; but if the bead is cool, it must be +previously moistened. Expose this bead to the oxidation flame until it +ceases to change, then allow it to cool, when it should be exposed to +the reduction flame. Look for the following in the oxidation flame: + + (1.) Whether the heated substance is fused to a clear bead or + not, and whether the bead remains transparent after cooling. The + beads of some substances, for instance those of the alkaline + earths, are clear while hot; but upon cooling, are milk-white and + enamelled. Some substances give a clear bead when heated and when + cold, but appear enamelled when heated intermittingly or with a + flame which changes often from oxidation to reduction, or with an + unsteady flame produced by too strong a blast. The reason is an + incomplete fusion, while from the basic borate compound a part of + the base is separated. As the boracic acid is capable of + dissolving more in the heat, a bead will be clear while hot, + enamelled when cold, as a part in the latter instance will become + separated. + + (2.) Whether the substance dissolves easily or not, and whether + it intumesces from arising gases. + + (3.) Whether the bead, when exposed to the oxidation flame, + exhibits any color, and whether the color remains after the bead + shall have cooled, or whether the color fades. + + (4.) Whether the bead exhibits any other reaction in the + reduction flame. + +The bead should not be overcharged with the substance under +examination, or it will become colored so deeply as not to present any +transparency, or the color light enough to discern its hue. + + +8. _Microcosmic Salt--Phosphate of Soda and Ammonia_--(NaO, NH^{4}O + +PO^{5}).--Dissolve six parts of phosphate of soda (2NaO, HO, PO^{5}), +and one part of pure chloride of Ammonium (NH^{4}Cl.), in two parts of +boiling water, and allow it to cool. The greatest part of the formed +double salt crystallizes, while the mother-liquid contains chloride of +sodium, and some of the double salt. The crystals must be dissolved in +as little boiling water as possible, and re-crystallized. These +crystals must be dried and powdered. + +When this double salt is heated, the water and the ammonia escape, +while the incombustible residue has a composition similar to borax, +viz., a free acid and an easily fusible salt. The effect of it is, +therefore, similar to the borax. The free phosphoric acid expels, +likewise, most other acids from their combinations, and combines with +metallic oxides. + +For supports, the platinum wire may be used, but the hook must be +smaller than when borax is used, or the bead will not adhere. As for +all the other experiments with this salt, the microscosmic salt is +used the same as borax. + + +9. _Nitrate of Cobalt._--(CoO, NO^{5}).--This salt can be prepared by +dissolving pure oxide of cobalt in diluted nitric acid, and +evaporating to dryness with a low heat. The dry residue should be +dissolved in ten parts of water, and filtered. The filtrate is now +ready for use, and should be kept in a bottle with a glass stopper. If +the pure oxide of cobalt cannot be procured, then it may be prepared +by mixing two parts of finely powdered _glance of cobalt_ with four +parts of saltpetre, and one part of dry carbonate of potassa with one +part of water free from carbonate of soda. This mixture should be +added in successive portions into a red-hot Hessian crucible, and the +heat continued until the mass is fused, or at least greatly diminished +in volume. The cooled mass must be triturated with hot water, and then +heated with hydrochloric acid until it is dissolved and forms a dark +green solution, which generally presents a gelatinous appearance, +occasioned by separated silica. The solution is to be evaporated to +dryness, the dry residue moistened with hydrochloric acid, boiled with +water, filtered and neutralized while hot with carbonate of ammonia, +until it ceases to give an acid reaction with test-paper. This must +now be filtered again, and carbonate of potassa added to the filtrate +as long as a precipitate is produced. This precipitate is brought upon +a filter and washed thoroughly, and then dissolved in diluted nitric +acid. This is evaporated to dryness, and one part of it is dissolved +in ten parts of water for use. + +The oxide of cobalt combines, with strong heat in the oxidation flame, +with various earths and infusible metallic oxides, and thus produces +peculiarly colored compounds, and is therefore used for their +detection; (alumina, magnesia, oxide of zinc, oxide of tin, etc.) Some +of the powdered substance is heated upon charcoal in the flame of +oxidation, and moistened with a drop of the solution of the nitrate of +cobalt, when the oxidation flame is thrown upon it. Alumina gives a +pure blue color, the oxide of zinc a bright green, magnesia a light +red, and the oxide of tin a bluish-green color; but the latter is only +distinctly visible after cooling. + +The dropping bottle, is the most useful apparatus for the purpose of +getting small quantities of fluid. It is composed of a glass tube, +drawn out to a point, with a small orifice. This tube passes through +the cork of the bottle. By pressing in the cork into the neck of the +bottle, the air within will be compressed, and the liquid will rise in +the tube. If now we draw the cork out, with the tube filled with the +fluid, and pressing the finger upon the upper orifice, the fluid can +be forced out in the smallest quantity, even to a fraction of a drop. + + +10. _Tin._--This metal is used in the form of foil, cut into strips +about half an inch wide. Tin is very susceptible of oxidation, and +therefore deprives oxidized substances of their oxygen very quickly, +when heated in contact with them. It is employed in blowpipe analysis, +for the purpose of producing in glass beads a lower degree of +oxidation, particularly if the substance under examination contains +only a small portion of such oxide. These oxides give a characteristic +color to the bead, and thus are detected. The bead is heated upon +charcoal in the reduction flame, with a small portion of the tin, +whereby some of the tin is melted and mixes with the bead. The bead +should be reduced quickly in the reduction flame, for by continuing +the blast too great a while, the oxide of tin separates the other +oxides in the reduced or metallic state, while we only require that +they shall only be converted into a sub-oxide, in order that its +peculiar color may be recognized in the bead. The addition of too much +tin causes the bead to present an unclean appearance, and prevents +the required reaction. + + +11. _Silica_ (SiO^{3}).--This acid does not even expel carbonic acid +in the wet way, but in a glowing heat it expels the strongest volatile +acids. In blowpipe analysis, we use it fused with carbonate of soda to +a bead, as a test for sulphuric acid, and in some cases for phosphoric +acid. Also with carbonate of soda and borax, for the purpose of +separating tin from copper. + +Finely powdered quartz will answer these purposes. If it cannot be +procured, take well washed white sand and mix it with two parts of +carbonate of soda and two parts of carbonate of potassa. Melt the +materials together, pound up the cooled mass, dissolve in hot water, +filter, add to the filtrate hydrochloric acid, and evaporate to +dryness. Moisten the dry residue with hydrochloric acid, and boil in +water. The silica remains insoluble. It should be washed well, dried, +and heated, and then reduced to powder. + + +12. TEST-PAPERS.--(_a._) _Blue, Litmus Paper._--Dissolve one part of +litmus in six or eight parts of water, and filter. Divide the filtrate +into two parts. In one of the parts neutralize the free alkali by +stirring it with a glass rod dipped in diluted sulphuric acid, until +the fluid appears slightly red. Then mix the two parts together, and +draw slips of unsized paper, free from alkali, such as fine filtering +paper. Hang these strips on a line to dry, in the shade and free from +floating dust. If the litmus solution is too light, it will not give +sufficient characteristic indications, and if too dark it is not +sensitive enough. The blue color of the paper should be changed to +red, when brought in contact with a solution containing the minutest +trace of free acid; but it should be recollected that the neutral +salts of the heavy metals produce the same change. + +(_b._) _Red Litmus Paper._--The preparation of the red litmus paper is +similar to the above, the acid being added until a red color is +obtained. Reddened litmus paper is a very sensitive reagent for free +alkalies, the carbonates of the alkalies, alkaline earths, sulphides +of the alkalies and of the alkaline earths, and alkaline salts with +weak acids, such as boracic acid. These substances restore the +original blue color of the litmus. + +(_c._) _Logwood Paper._--Take bruised logwood, boil it in water, +filter, and proceed as above. Logwood paper is a very delicate test +for free alkalies, which impart a violet tint to it. It is sometimes +used to detect hydrofluoric acid, which changes its color to yellow. + +All the test-papers are to be cut into narrow strips, and preserved in +closely stopped vials. The especial employment of the test-papers we +shall allude to in another place. + + +B. ESPECIAL REAGENTS. + + +13. _Fused Boracic Acid_ (BO^{3}).--The commercial article is +sufficiently pure for blowpipe analysis. It is employed in some cases +to detect phosphoric acid, and also minute traces of copper in lead +compounds. + + +14. _Fluorspar_ (CaFl^{2}).--This substance should be pounded fine and +strongly heated. Fluorspar is often mixed with boracic acid, which +renders it unfit for analytical purposes. Such an admixture can be +detected if it be mixed with bisulphate of potassa, and exposed upon +platinum wire to the interior or blue flame. It is soon fused, the +boracic acid is reduced and evaporated, and by passing through the +external flame it is reoxidized, and colors the flame green. We use +fluorspar mixed with bisulphate of potassa as a test for lithia and +boracic acid in complicated compounds. + + +15. _Oxalate of Nickel_ (NiO, [=]O).--It is prepared by dissolving the +pure oxide of nickel in diluted hydrochloric acid. Evaporate to +dryness, dissolve in water, and precipitate with oxalate of ammonia. +The precipitate must be washed with caution upon a filter, and then +dried. It is employed in blowpipe analysis to detect salts of potassa +in the presence of sodium and lithium. + + +16. _Oxide of Copper_ (CuO).--Pure metallic copper is dissolved in +nitric acid. The solution is evaporated in a porcelain dish to +dryness, and gradually heated over a spirit-lamp, until the blue color +of the salt has disappeared and the mass presents a uniform black +color. The oxide of copper so prepared must be powdered, and preserved +in a vial. It serves to detect, in complicated compounds, minute +traces of chlorine. + + +17. _Antimoniate of Potassa_ (KO, SbO^{6}).--Mix four parts of the +bruised metal of antimony, with nine parts of saltpetre. Throw this +mixture, in small portions, into a red-hot Hessian crucible, and keep +it at a glowing heat for awhile after all the mixture is added. Boil +the cooled mass with water, and dry the residue. Take two parts of +this, and mix it with one part of dry carbonate of potassa, and expose +this to a red heat for about half an hour. Then wash the mass in cold +water, and boil the residue in water; filter, evaporate the filtrate +to dryness, and then, with a strong heat, render it free of water. +Powder it while it is warm, and preserve it in closed vials. It is +used for the detection of small quantities of charcoal in compound +substances, as it shares its oxygen with the carbonaceous matter, the +antimony becomes separated, and carbonate of potassa is produced, +which restores red litmus paper to blue, and effervesces with acids. + + +18. _Silver Foil._--A small piece of silver foil is used for the +purpose of detecting sulphur and the sulphides of the metals, which +impart a dark stain to it. If no silver foil is at hand, strips of +filtering paper, impregnated with acetate of lead, will answer in many +cases. + + +19. _Nitroprusside of Sodium_ (Fe^{2}Cy^{5}, NO^{5}, 2Na).--This is a +very delicate test for sulphur, and was discovered by Dr. Playfair. +This test has lately been examined with considerable ability by Prof. +J.W. Bailey, of West Point. If any sulphate or sulphide is heated by +the blowpipe upon charcoal with the carbonate of soda, and the fused +mass is placed on a watch-glass, with a little water, and a small +piece of the nitroprusside of sodium is added, there will be produced +a splendid purple color. This color, or reaction, will be produced +from any substance containing sulphur, such as the parings of the +nails, hair, albumen, etc. In regard to these latter substances, the +carbonate of soda should be mixed with a little starch, which will +prevent the loss of any of the sulphur by oxidation. Coil a piece of +hair around a platinum wire, moisten it, and dip it into a mixture of +carbonate of soda, to which a little starch has been added, and then +heat it with the blowpipe, when the fused mass will give with the +nitroprusside of sodium the characteristic purple reaction, indicative +of the presence of sulphur. With the proper delicacy of manipulation, +a piece of hair, half an inch in length, will give distinct +indications of sulphur. + +_Preparation._--The nitroprussides of sodium and potassium (for either +salt will give the above reactions), are prepared as follows: One atom +(422 grains) of pulverized ferrocyanide of potassium is mixed with +five atoms of commercial nitric acid, diluted with an equal quantity +of water. One-fifth of this quantity (one atom) of the acid is +sufficient to transfer the ferrocyanide into nitroprusside; but the +use of a larger quantity is found to give the best results. The acid +is poured all at once upon the ferrocyanide, the cold produced by the +mixing being sufficient to moderate the action. The mixture first +assumes a milky appearance, but after a little while, the salt +dissolves, forming a coffee-colored solution, and gases are disengaged +in abundance. When the salt is completely dissolved, the solution is +found to contain ferrocyanide (red prussiate) of potassium, mixed with +nitroprusside and nitrate of the same base. It is then immediately +decanted into a large flask, and heated over the water-bath. It +continues to evolve gas, and after awhile, no longer yields a dark +blue precipitate with ferrous salts, but a dark green or slate-colored +precipitate. It is then removed from the fire, and left to +crystallize, whereupon it yields a large quantity of crystals of +nitre, and more or less oxamide. The strongly-colored mother liquid is +then neutralized with carbonate of potash or soda, according to the +salt to be prepared, and the solution is boiled, whereupon it +generally deposits a green or brown precipitate, which must be +separated by filtration. The liquid then contains nothing but +nitroprusside and nitrate of potash or soda. The nitrates being the +least soluble, are first crystallized, and the remaining liquid, on +farther evaporation, yields crystals of the nitroprusside. The sodium +salt crystallizes most easily.--(PLAYFAIR.) + +As some substances, particularly in complicated compounds, are not +detected with sufficient nicety in the dry way of analysis, it will +often be necessary to resort to the wet way. It is therefore necessary +to have prepared the reagents required for such testing, as every +person, before he can become an expert blowpipe analyst, must be +acquainted with the characteristic tests as applied in the wet way. + + * * * * * + + + + +Part II. + +INITIATORY ANALYSIS. + + +Qualitative analysis refers to those examinations which relate simply +to the presence or the absence of certain substances, irrespective of +their quantities. But before we take cognizance of special +examinations, it would facilitate the progress of the student to pass +through a course of Initiatory Exercises. These at once lead into the +special analysis of all those substances susceptible of examination by +the blowpipe. The Initiatory Analysis is best studied by adopting the +following arrangement: + + +1. EXAMINATIONS WITH THE GLASS BULB. + + +The glass of which the bulb is made should be entirely free from lead, +otherwise fictitious results will ensue. If the bulb be of flint +glass, then by heating it, there is a slightly iridescent film caused +upon the surface of the glass, which may easily be mistaken for +arsenic. Besides, this kind of glass is easily fusible in the +oxidating flame of the blowpipe, while, in the reducing flame, its +ready decomposition would preclude its use entirely. The tube should +be composed of the potash or hard Bohemian glass, should be perfectly +white, and very thin, or the heat will crack it. + +The tube should be perfectly clean, which can be easily attained by +wrapping a clean cotton rag around a small stick, and inserting it in +the tube. Before using the tube, see also that it is perfectly dry. + +The quantity of the substance put into the tube for examination should +be small. From one to three grains is quite sufficient, as a general +rule, but circumstances vary the quantity. The sides of the tube +should not catch any of the substance as it is being placed at the +bottom of the tube, or into the bulb. If any of the powder, however, +should adhere, it should be pushed down with a roll of clean paper, or +the clean cotton rag referred to above. + +In submitting the tube to the flame, it should be heated at first very +gently, the heat being increased until the glass begins to soften, +when the observations of what is ensuing within it may be made. + +If the substance be of an organic nature, a peculiar empyreumatic odor +will be given off. If the substance chars, then it may be inferred +that it is of an organic nature. The matters which are given off and +cause the empyreumatic odor, are a peculiar oil, ammonia, carbonic +acid, acetic acid, water, cyanogen, and frequently other compounds. If +a piece of paper is heated in the bulb, a dark colored oil condenses +upon the sides of the tube, which has a strong empyreumatic odor. A +piece of litmus paper indicates that this oil is acid, as it is +quickly changed to red by contact with it. A black residue is now left +in the tube, and upon examination we will find that it is charcoal. +If, instead of the paper, a piece of animal substance is placed in +the bulb, the reddened litmus paper will be converted into its +original blue color, while charcoal will be left at the bottom of the +tube. + +A changing of the substance, however, to a dark color, should not be +accepted as an invariable indication of charcoal, as some inorganic +bodies thus change color, but the dark substance will not be likely to +be mistaken for charcoal. By igniting the suspected substance with +nitrate of potassa, it can quickly be ascertained whether it is +organic or not, for if the latter, the vivid deflagration will +indicate it. + +If the substance contains water, it will condense upon the cold +portion of the tube, and may be there examined as to whether it is +acid or alkaline. If the former, the matter under examination is, +perhaps, vegetable; if the latter, it is of an animal nature. The +water may be that fluid absorbed, or it may form a portion of its +constitution, + +If the substance contain _sulphur_, the sublimate upon the cold part +of the tube may be recognized by its characteristic appearance, +especially if the substance should be a sulphide of tin, copper, +antimony, or iron. The hyposulphites, and several other sulphides, +also give off sulphur when heated. The volatile metals, mercury and +arsenic, will, however, sublime without undergoing decomposition. As +the sulphide of arsenic may be mistaken, from its color and +appearance, for sulphur, it must be examined especially for the +purpose of determining that point. + +_Selenium_ will likewise sublime by heat as does sulphur. This is the +case if selenides are present. Selenium gives off the smell of decayed +horse-radish. + +When the persalts are heated they are reduced to protosalts, with the +elimination of a part of their acid. This will be indicated by the +blue litmus paper. + +If some of the neutral salts containing a volatile acid be present, +they will become decomposed. For instance, the red nitrous acid water +of the nitrates will indicate the decomposition of the salt, +especially if it be the nitrate of a metallic oxide. + +If there is an odor of sulphur, then it is quite probable, if no free +sulphur be present, that a hyposulphite is decomposed. + +If an oxalate be present, it is decomposed with the evolution of +carbonic oxide, which may be inflamed at the mouth of the tube; but +there are oxalates that give off carbonic acid gas, which, of course, +will not burn. A cyanide will become decomposed and eliminate nitrogen +gas, while the residue is charred. Some cyanides are, however, not +thus decomposed, as the dry cyanides of the earths and alkalies. + +There are several oxides of metals which will sublime, and may be thus +examined in the tube. _Arsenious acid_ sublimes with great ease in +minute octohedral crystals. The oxides of tellurium and antimony will +sublime, the latter in minute glittering needles. + +There are several metals which will sublime, and may be examined in +the cold portion of the tube. _Mercury_ condenses upon the tube in +minute globules. These often do not present the metallic appearance +until they are disturbed with a glass rod, when they attract each +other, and adhere as small globules. Place in the tube about a grain +of red precipitate of the drug stores and apply heat, when the oxide +will become decomposed, its oxygen will escape while the vaporized +mercury will condense upon the cold portion of the tube, and may there +be examined with a magnifying glass. + +_Arsenic_, when vaporized, may be known by its peculiar alliaceous +odor. Arsenic is vaporized from its metallic state, and likewise from +its alloys. Several compounds which contain arsenic will also sublime, +such as the arsenical cobalt. Place in the bulb a small piece of +arsenical cobalt or "fly-stone," and apply heat. The sulphide of +arsenic will first rise, but soon the arsenic will adhere to the sides +of the tube. + +The metals tellurium and cadmium are susceptible of solution, but the +heat required is a high one. This is best done upon charcoal. + +The _perchloride of mercury_ sublimes undecomposed in the bulb, +previously undergoing fusion. + +The _protochloride of mercury_ likewise sublimes, but it does not +undergo fusion first, as is the case with the corrosive sublimate. + +The _ammoniacal salts_ all are susceptible of sublimation, which they +do without leaving a residue. There are, however, several which +contain fixed acids, which latter are left in the bulb. This is +particularly the case with the phosphates and borates. A piece of red +litmus paper will readily detect the escaping ammonia, while its odor +will indicate its presence with great certainty. The halogen compounds +of mercury, we should have mentioned, also sublime, the red iodide +giving a yellow sublimate. + +The bulb is also a convenient little instrument for the purpose of +heating those substances which phosphoresce, and likewise those salts +that decrepitate. + +Should the above reactions not be readily discerned, it should not be +considered as an indication that the substances are not present, for +they are frequently expelled in such combinations that the above +reactions will not take place. This is often the case with sulphur, +selenium, arsenic, and tellurium. It frequently happens, likewise, +that these substances are in such combinations that heat alone will +not sublime them; or else two or more of them may arise together, and +thus complicate the sublimate, so that the eye cannot readily detect +either substance. Sometimes sulphur and arsenic will coat the tube +with a metal-like appearance, which is deceptive. This coating +presents a metallic lustre at its lower portion, but changing, as it +progresses upward, to a dark brown, light brown, orange or yellow; +this sublimate being due to combinations of arsenic and sulphur, which +compounds are volatilized at a lower temperature than metallic +arsenic. + +If certain reagents are mixed with many substances, changes are +effected which would not ensue with heat alone. _Formiate of soda_ +possesses the property of readily reducing metallic oxides. When this +salt is heated, it gives off a quantity of carbonic oxide gas. This +gas, when in the presence of a metallic oxide, easily reduces the +metal, by withdrawing its oxygen from it, and being changed into +carbonic oxide. If a little fly-stone is mixed with some formiate of +soda, and heated in the bulb, the arsenic is reduced, volatilized, and +condenses in the cool portion of the tube. By this method, the +smallest portion of a grain of the arsenical compound may be thus +examined with the greatest readiness. If the residue is now washed, by +which the soda is got rid of, the metallic arsenic may be obtained in +small spangles. If the compound examined be the sulphide of antimony, +the one-thousandth part can be readily detected, and hence this method +is admirably adapted to the examination of medicinal antimonial +compounds. The arsenites of silver and copper are reduced by the +formiate of soda to their metals, mixed with metallic arsenic. The +mercurial salts are all reduced with the metal plainly visible as a +bright silvery ring on the cool portion of the tube. The chloride and +nitrate of silver are completely reduced, and may be obtained after +working out the soda, as bright metallic spangles. The salts of +antimony and zinc are thus reduced; also the sulphate of cadmium. The +sublimate of the latter, although in appearance not unlike that of +arsenic, can easily be distinguished by its brighter color. It is, in +fact, the rich yellow of this sublimate which has led artists to adopt +it as one of their most valued pigments. + + +2. EXAMINATIONS IN THE OPEN TUBE. + + +The substance to be operated upon should be placed in the tube, about +half an inch from the end, and the flame applied at first very +cautiously, increasing gradually to the required temperature. The +tube, in all these _roasting_ operations, as they are termed, should +be held in an inclined position. The nearer perpendicular the tube is +held, the stronger is the draught of air that passes through it. If +but little heat is required in the open tube operation, the +spirit-lamp is the best method of applying the heat. But if a greater +temperature is required, then recourse must be had to the blowpipe. +Upon the angle of inclination of the tube depends the amount of air +that passes through it, and therefore, the rapidity of the draught +may be easily regulated at the will of the operator. The inclination +of the tube may, as a general rule, be about the angle represented in +Fig. 14. + +[Illustration Fig. 14.] + +The length of the tube must be about six inches, so that the portion +upon which the substance rested in a previous examination may be cut +off. The portion of the tube left will answer for several similar +operations. + +When the substance is under examination, we should devote our +attention to the nature of the sublimates, and to that of the _odors_ +of the gases. If sulphur be in the substance experimented upon, the +characteristic odor of sulphurous acid gas will readily indicate the +sulphur. If metallic sulphides, for instance, are experimented upon, +the sulphurous acid gas eliminated will readily reveal their presence. +As it is a property of this gas to bleach, a piece of Brazil-wood test +paper should be held in the mouth of the tube, when its loss of color +will indicate the presence of the sulphurous acid. It often happens, +too, that a slight deposition of sulphur will be observed upon the +cool portion of the tube. This is particularly the case with those +sulphides, which yield sublimates of sulphur when heated in the bulb. + +_Selenium_ undergoes but slight oxidation, but it becomes readily +volatilized, and may be observed on the cool portion of the tube. At +the same time the nose, if applied close to the end of the tube, will +detect the characteristic odor of rotten horse-radish. Arsenic also +gives its peculiar alliaceous odor, which is so characteristic that it +can be easily detected. A few of the arsenides produce this odor. The +_sublimates_ should be carefully observed, as they indicate often with +great certainty the presence of certain substances; for instance, that +of arsenic. The sublimate, in this case, presents itself as the +arsenious acid, or the metallic arsenic itself. If it be the former, +it may be discerned by aid of the magnifying glass as beautiful +glittering octohedral crystals. If the latter, the metallic lustre +will reveal it. + +But it will be observed that while some of the arsenides are sublimed +at a comparatively low temperature, others require a very high one. + +_Antimony_ gives a white sublimate when its salts are roasted, as the +sulphide, or the antimonides themselves, or the oxide of this metal. +This white sublimate is not antimonious acid, but there is mixed with +it the oxide of antimony with which the acid is sublimed. As is the +case with arsenious acid, the antimonious acid may, by dexterous +heating, be driven from one portion of the tube to another. + +_Tellurium_, or its acid and oxide, may be got as a sublimate in the +tube. The tellurious acid, unlike the arsenious and antimonious acids, +cannot be driven from one portion of the tube to another, but, on the +contrary, it fuses into small clear globules, visible to the naked eye +sometimes, but quite so with the aid of the magnifying glass. + +_Lead_, or its chloride, sublimes like tellurium, and, like that +substance, fuses into globules or drops. + +_Bismuth_, or its sulphide, sublimes into an orange or brownish +globules, when it is melted, as directed above, for tellurium. The +color of the bismuth and lead oxides are somewhat similar, although +that of the latter is paler. + +If any mineral containing _fluorine_, is fused, first with the +microcosmic salt bead, then put into the tube, and the flame of the +blowpipe be directed _into_ the tube upon the bead, hydrofluoric acid +is disengaged and attacks the inside of the tube. The fluoride of +calcium, or fluorspar, may be used for this experiment. + +During the roasting, a brisk current of air should be allowed to pass +through the tube, whereby unoxidized matter may be prevented from +volatilization, and the clogging up of the substance under examination +be prevented. + + +3. EXAMINATIONS UPON CHARCOAL. + + +In making examinations upon charcoal, it is quite necessary that the +student should make himself familiar with the different and +characteristic appearances of the deposits upon the charcoal. In this +case I have found the advice given by Dr. Sherer to be the best; that +is, to begin with the examination of the pure materials first, until +the eye becomes familiarized with the appearances of their +incrustations upon charcoal. + +The greater part of the metals fuse when submitted to the heat of the +blowpipe, and if exposed to the outer flame, they oxidize. These +metals, termed the noble metals, do not oxidize, but they fuse. The +metals platinum, iridium, rhodium, osmium and palladium do not fuse. +The metal osmium, if exposed to the flame of oxidation, fuses and is +finally dissipated as osmic acid. In the latter flame, the salts of +the noble metals are reduced to the metallic state, and the charcoal +is covered with the bright metal. + +We shall give a brief description of the appearance of the principal +elementary bodies upon being fused with charcoal. This plan is that +deemed the most conducive to the progress of the student, by +Berzelius, Plattner, and Sherer. Experience has taught us that this +method is the most efficient that could have been devised as an +initiatory exercise for the student, ere he commences a more concise +and methodical method of analysis. In these reactions upon charcoal, +we shall follow nearly the language of Plattner and Sherer. + +SELENIUM is not difficult of fusion, and gives off brown fumes in +either the oxidation or reduction flame. The deposit upon the charcoal +is of a steel-grey color, with a slightly metallic lustre. The deposit +however that fuses outside of this steel-grey one is of a dull violet +color, shading off to a light brown. Under the flame of oxidation this +deposit is easily driven from one portion of the charcoal to another, +while the application of the reducing flame volatilizes it with the +evolution of a beautiful blue light. The characteristic odor of +decayed horse-radish distinguishes the volatilization of this metal. + +TELLURIUM.--This metal fuses with the greatest readiness, and is +reduced to vapor under both flames with fumes, and coats the charcoal +with a deposit of tellurous acid. This deposit is white near the +centre, and is of a dark yellow near the edges. It may be driven from +place to place by the flame of oxidation, while that of reduction +volatilizes it with a green flame. If there be a mixture of selenium +present, then the color of the flame is bluish-green. + +ARSENIC.--This metal is volatilized without fusing, and covers the +charcoal both in the oxidizing and reducing flames with a deposit of +arsenious acid. This coating is white in the centre, and grey towards +the edges, and is found some distance from the assay. By the most +gentle application of the flame, it is immediately volatilized, and if +touched for a moment with the reducing flame, it disappears, tinging +the flame pale blue. During volatilization a strong garlic odor is +distinctly perceptible, very characteristic of arsenic, and by which +its presence in any compound may be immediately recognized. + +ANTIMONY.--This metal fuses readily, and coats the charcoal under both +flames with antimonious acid. This incrustation is of a white color +where thick, but of a bluish tint where it is thin, and is found +nearer to the assay than that of arsenic. When greatly heated by the +flame of oxidation, it is driven from place to place without coloring +the flame, but when volatilized by the flame of reduction, it tinges +the flame blue. As antimonious acid is not so volatile as arsenious +acid, they may thus be easily distinguished from one another. + +When metallic antimony is fused upon charcoal, and the metallic bead +raised to a red heat, if the blast be suspended, the fluid bead +remains for some time at this temperature, giving off opaque white +fumes, which are at first deposited on the surrounding charcoal, and +then upon the bead itself, covering it with white, pearly crystals. +The phenomenon is dependent upon the fact, that the heated button of +antimony, in absorbing oxygen from the air, developes sufficient heat +to maintain the metal in a fluid state, until it becomes entirely +covered with crystals of antimonious acid so formed. + +BISMUTH.--This metal fuses with ease, and under both flames covers the +charcoal with a coating of oxide, which, while hot, is of an +orange-yellow color, and after cooling, of a lemon-yellow color, +passing, at the edges, into a bluish white. This white coating +consists of the carbonate of bismuth. The sublimate from bismuth is +formed at a less distance from the assay than is the case with +antimony. It may be driven from place to place by the application of +either flame; but in so doing, the oxide is first reduced by the +heated charcoal, and the metallic bismuth so formed is volatilized and +reoxidized. The flame is uncolored. + +LEAD.--This metal readily fuses under either flame, and incrusts the +charcoal with oxide at about the same distance from the assay as is +the case with bismuth. The oxide is, while hot, of a dark lemon-yellow +color, but upon cooling, becomes of a sulphur yellow. The carbonate +which is formed upon the charcoal, beyond the oxide, is of a +bluish-white color. If the yellow incrustation of the oxide be heated +with the flame of oxidation, it disappears, undergoing changes similar +to those of bismuth above mentioned. Under the flame of reduction, +it, however, disappears, tinging the flame blue. + +CADMIUM.--This metal fuses with ease, and, in the flame of oxidation, +takes fire, and burns with a deep yellow color, giving off brown +fumes, which coat the charcoal, to within a small distance of the +assay, with oxide of cadmium. This coating exhibits its characteristic +reddish-brown color most clearly when cold. Where the coating is very +thin, it passes to an orange color. As oxide of cadmium is easily +reduced, and the metal very volatile, the coating of oxide may be +driven from place to place by the application of either flame, to +neither of which does it impart any color. Around the deposit of +oxide, the charcoal has occasionally a variegated tarnish. + +ZINC.--This metal fuses with ease, and takes fire in the flame of +oxidation, burning with a brilliant greenish-white light, and forming +thick white fumes of oxide of zinc, which coat the charcoal round the +assay. This coating is yellow while hot, but when perfectly cooled, +becomes white. If heated with the flame of oxidation, it shines +brilliantly, but is not volatilized, since the heated charcoal is, +under these circumstances, insufficient to effect its reduction. Even +under the reducing flame, it disappears very slowly. + +TIN.--This metal fuses readily, and, in the flame of oxidation, +becomes covered with oxide, which, by a strong blast, may be easily +blown off. In the reducing flame, the fused metal assumes a white +surface, and the charcoal becomes covered with oxide. This oxide is of +a pale yellow color while hot, and is quite brilliant when the flame +of oxidation is directed upon it. After cooling, it becomes white. It +is found immediately around the assay, and cannot be volatilized by +the application of either flame. + +MOLYBDENUM.--This metal, in powder, is infusible before the blowpipe. +If heated in the outer flame, it becomes gradually oxidized, and +incrusts the charcoal, at a small distance from the assay, with +molybdic acid, which, near the assay, forms transparent crystalline +scales, and is elsewhere deposited as a fine powder. The incrustation, +while hot, is of a yellow color, but becomes white after cooling. It +may be volatilized by heating with either flame, and leaves the +surface of the charcoal, when perfectly cooled, of a dark-red copper +color, with a metallic lustre, due to the oxide of molybdenum, which +has been formed by the reducing action of the charcoal upon the +molybdic acid. In the reducing flame, metallic molybdenum remains +unchanged. + +SILVER.--This metal, when fused alone, and kept in this state for some +time, under a strong oxidizing flame, covers the charcoal with a thin +film of dark reddish-brown oxide. If the silver be alloyed with lead, +a yellow incrustation of the oxide of that metal is first formed, and +afterwards, as the silver becomes more pure, a dark red deposit is +formed on the charcoal beyond. If the silver contains a small quantity +of antimony, a white incrustation of antimonious acid is formed, which +becomes red on the surface if the blast be continued. And if lead and +antimony are both present in the silver, after the greater part of +these metals have been volatilized, a beautiful crimson incrustation +is produced upon the charcoal. This result is sometimes obtained in +fusing rich silver ores on charcoal. + + +SULPHIDES, CHLORIDES, IODIDES, AND BROMIDES. + +In blowpipe experiments, it rarely occurs that we have to deal with +pure metals, which, if not absolutely non-volatile, are recognized by +the incrustation they form upon charcoal. Some compound substances, +when heated upon charcoal, form white incrustations, resembling that +formed by antimony, and which, when heated, may, in like manner, be +driven from place to place. Among these are certain sulphides, as +sulphide of potassium, and sulphide of sodium, which are formed by the +action of the reducing flame upon the sulphates of potassa and soda, +and are, when volatilized, reconverted into those sulphates, and as +such deposited on the charcoal. No incrustation is, however, formed, +until the whole of the alkaline sulphate has been absorbed into the +charcoal, and has parted with its oxygen. As sulphide of potassium is +more volatile than sulphide of sodium, an incrustation is formed from +the former sooner than from the latter of these salts, and is +considerably thicker in the former case. If the potash incrustation be +touched with the reducing flame, it disappears with a violet-colored +flame; and if a soda incrustation be treated in like manner, an +orange-yellow flame is produced. + +Sulphide of lithium, formed by heating the sulphate in the reducing +flame, is volatilized in similar manner by a strong blast, although +less readily than the sulphide of sodium. It affords a greyish white +film, which disappears with a crimson flame when submitted to the +reducing flame. + +Besides the above, the sulphides of bismuth and lead give, when heated +in either flame, two different incrustations, of which the more +volatile is of a white color, and consists in the one case of sulphate +of lead, and in the other of sulphate of bismuth. If either of these +be heated under the reducing flame, it disappears in the former case +with a bluish flame, in the latter unaccompanied by any visible flame. +The incrustation formed nearest to the assay consists of the oxide of +lead or bismuth, and is easily recognized by its color when hot and +after cooling. There are many other metallic sulphides, which, when +heated by the blowpipe flame, cover the charcoal with a white +incrustation, as sulphide of antimony, sulphide of zinc, and sulphide +of tin. In all these cases, however, the incrustation consists of the +metallic oxide alone, and either volatilizes or remains unchanged, +when submitted to the oxidizing flame. + +Of the metallic chlorides there are many which, when heated on +charcoal with the blowpipe flame, are volatilized and redeposited as a +white incrustation. Among these are the chlorides of potassium, +sodium, and lithium, which volatilize and cover the charcoal +immediately around the assay with a thin white film, after they have +been fused and absorbed into the charcoal, chloride of potassium forms +the thickest deposit, and chloride of lithium the thinnest, the +latter being moreover of a greyish-white color. The chlorides of +ammonium, mercury, and antimony volatilize without fusing. + +The chlorides of zinc, cadmium, lead, bismuth, and tin first fuse and +then cover the charcoal with two different incrustations, one of which +is a white volatile chloride, and the other a less volatile oxide of +the metal. + +Some of the incrustations formed by metallic chlorides disappear with +a colored flame when heated with the reducing flame; thus chloride of +potassium affords a violet flame, chloride of sodium an orange one, +chloride of lithium a crimson flame, and chloride of lead a blue one. +The other metals mentioned above volatilize without coloring the +flame. + +The chloride of copper fuses and colors the flame of a beautiful blue. +Moreover, if a continuous blast be directed upon the salt, a part of +it is driven off in the form of white fumes which smell strongly of +chlorine, and the charcoal is covered with incrustations of three +different colors. That which is formed nearest to the assay is of a +dark grey color, the next, a dark yellow passing into brown, and the +most distant of a bluish white color. If this incrustation be heated +under the reducing flame, it disappears with a blue flame. + +Metallic iodides and bromides behave upon charcoal in a similar manner +to the chlorides. Those principally deserving of mention are the +bromides and iodides of potassium and sodium. These fuse upon +charcoal, are absorbed into its pores, and volatilize in the form of +white fumes, which are deposited upon the charcoal at some distance +from the assay. When the saline films so formed are submitted to the +reducing flame, they disappear, coloring the flame in the same manner +as the corresponding chlorides. + + +4. EXAMINATIONS IN THE PLATINUM FORCEPS. + + +Before the student attempts to make an examination in the platinum +forceps or tongs, he should first ascertain whether or not it will +act upon the platinum. If the substance to be examined shall act +chemically upon the platinum, then it should be examined on the +charcoal, and the color of the flame ascertained as rigidly as +possible. The following list of substances produce the color attached +to them. + +A. VIOLET. + + Potash, and all its compounds, with the exception of the phosphate + and the borate, tinge the color of the flame violet. + +B. BLUE. + + Chloride of copper, Intense blue. + Lead, Pale clear blue. + Bromide of copper, Bluish green. + Antimony, Bluish green. + Selenium, Blue. + Arsenic, English green. + +C. GREEN. + + Ammonia, Dark green. + Boracic acid, Dark green. + Copper, Dark green. + Tellurium, Dark green. + Zinc, Light green. + Baryta Apple green. + Phosphoric acid, Pale green. + Molybdic acid, Apple green. + Telluric acid, Light green. + +D. YELLOW. + + Soda, Intense yellow. + Water, Feeble yellow. + +E. RED. + + Strontia, Intense crimson. + Lithia, Purplish red. + Potash, Violet red. + Lime, Purplish red. + +The student may often be deceived in regard to the colors: for +instance, if a small splinter of almost any mineral be held at the +point of the flame of oxidation, it will impart a very slight yellow +to the flame. This is caused, doubtless, by the water contained in the +mineral. If the piece of platinum wire is used, and it should be wet +with the saliva, as is frequently done by the student, then the small +quantity of soda existing in that fluid will color the flame of a +light yellow hue. + + +A. THE VIOLET COLOR. + +The salts of potash, with the exception of the borate and the +phosphate, color the flame of a rich violet hue. This color is best +discovered in the outer flame of the blowpipe, as is the case with all +the other colors. The flame should be a small one, with a lamp having +a small wick, while the orifice of the blowpipe must be quite small. +These experiments should likewise be made in a dark room, so that the +colors may be discerned with the greatest ease. In investigating with +potash for the discernment of color, it should be borne in mind that +the least quantity of soda will entirely destroy the violet color of +the potash, by the substitution of its own strong yellow color. If +there be not more than the two hundredth part of soda, the violet +reaction of the potash will be destroyed. This is likewise the case +with the presence of lithia, for its peculiar red color will destroy +the violet of the potash. Therefore in making investigations with the +silicates which contain potash, the violet color of the latter can +only be discerned when they are free from soda and lithia. + + +B. THE BLUE COLOR. + +(_a._) _The Chloride of Copper._--Any of the chlorides produce a blue +color in the blowpipe flame, or any salt which contains chlorine will +show the blue tint, as the color in this case is referable to the +chlorine itself. There are, however, some chlorides which, in +consequence of the peculiar reactions of their bases, will not produce +the blue color, although in these cases the blue of the chlorine will +be very likely to blend itself with the color produced by the base. +The chloride of copper communicates an intense blue to the flame, when +fused on the platinum wire. If the heat be continued until the +chlorine is driven off, then the greenish hue of the oxide of copper +will be discerned. + +(_b._) _Lead._--Metallic lead communicates to the flame a pale blue +color. The oxide reacts in the same manner. The lead-salts, whose +acids do not interfere with the color, impart also a fine blue to the +flame, either in the platina forceps, or the crooked wire. + +(_c._) _Bromide of Copper._--This salt colors the flame of a +bluish-green color, but when the bromine is driven off, then we have +the green of the oxide of copper. + +(_d._) _Antimony._--This metal imparts a blue color to the blowpipe +flame, but if the metal is in too small a quantity, then the color is +a brilliant white. If antimony is fused on charcoal, the fused metal +gives a blue color. The white sublimate which surrounds the fused +metal, being subjected to the flame of oxidation, disappears from the +charcoal with a bluish-green color. + +(_e._) _Selenium._--If fused in the flame of oxidation, it imparts to +the flame a deep blue color. The incrustation upon charcoal gives to +the flame the same rich color. + +(_f._) _Arsenic._--The arseniates and metallic arsenic itself impart +to the blowpipe flame a fine blue color, provided that there is no +other body present which may have a tendency to color the flame with +its characteristic hue. The sublimate of arsenious acid which +surrounds the assay, will give the same blue flame, when dissipated by +the oxidation flame. The platinum forceps will answer for the +exhibition of the color of arsenic, even though the salts be +arseniates, whose bases possess the property of imparting their +peculiar color to the flame, such as the arseniate of lime. + + +C. THE GREEN COLOR. + +(_a._) _Ammonia._--The salts of ammonia, when heated before the +blowpipe, and just upon the point of disappearing, impart to the flame +a feeble though dark green color. This color, however, can only be +discerned in a dark room. + +(_b._) _Boracic Acid._--If any one of the borates is mixed with two +parts of a flux composed of one part of pulverized fluorspar, and four +and a half parts of bisulphate of potash, and after being melted, is +put upon the coil of a platinum wire, and held at the point of the +blue flame, soon after fusion takes place a dark green color is +discerned, but it is not of long duration. The above process is that +recommended by Dr. Turner. The green color of the borates may be +readily seen by dipping them, previously moistened with sulphuric +acid, into the upper part of the blue flame, when the color can be +readily discerned. If soda be present, then the rich green of the +boracic acid is marred by the yellow of the soda. Borax, or the +biborate of soda (NaO, 2BO_{3}) may be used for this latter reaction, +but if it be moistened with sulphuric acid, the green of the boracic +acid can then be seen. If the borates, or minerals which contain +boracic acid, are fused on charcoal with carbonate of potash, then +moistened with sulphuric acid and alcohol, then the bright green of +the boracic acid is produced, even if the mineral contains but a +minute portion of the boracic acid. + +(_c._) _Copper_. Nearly all the ores of copper and its salts, give a +bright green color to the blowpipe flame. Metallic copper likewise +colors the flame green, being first oxidized. If iodine, chlorine, and +bromine are present, the flame is considerably modified, but the +former at least intensifies the color. Many ores containing copper +also color the flame green, but the internal portion is of a bright +blue color if the compound contains lead, the latter color being due +to the lead. The native sulphide and carbonate of copper should be +moistened with sulphuric acid, while the former should be previously +roasted. If hydrochloric acid is used for moistening the salts, then +the rich green given by that moistened with the sulphuric acid is +changed to a blue, being thus modified by the chlorine of the acid. +Silicates containing copper, if heated in the flame in the platinum +forceps, impart a rich green color to the outer flame. In fact, if any +substance containing copper be submitted to the blowpipe flame, it +will tinge it green, provided there be no other substance present to +impart its own color to the flame, and thus modify or mar that of the +copper. + +(_d._) _Tellurium._--If the flame of reduction is directed upon the +oxide of tellurium placed upon charcoal, a green color is imparted to +it. If the telluric acid be placed upon platinum wire in the reduction +flame, the oxidation flame is colored green. Or if the sublimate be +dissipated by the flame of oxidation, it gives a green color. If +selenium be present, the green color is changed to a blue. + +(_e._) _Zinc._--The oxide of zinc, when strongly heated, gives a blue +flame. This is especially the case in the reducing flame. The flame is +a small one, however, and not very characteristic, as with certain +preparations of zinc the blue color is changed to a bright white. The +soluble salts of zinc give no blue color. + +(_f._) _Baryta._--The soluble salts of baryta, moistened, and then +submitted to the reduction flame, produce a green color. The salt +should be moistened, when the color will be strongly marked in the +outer flame. The insoluble salts do not produce so vivid a color as +the soluble salts, and they are brighter when they have previously +been moistened. The carbonate does not give a strong color, but the +acetate does, so long as it is not allowed to turn to a carbonate. The +chloride, when fused on the platinum wire, in the point of the +reduction flame, imparts a fine green color to the oxidation flame. +This tint changes finally to a faint dirty green color. The sulphate +of baryta colors the flame green when heated at the point of the +reduction flame. But neither the sulphate, carbonate, nor, in fact, +any other salt of baryta, gives such a fine green color as the +chloride. The presence of lime does interfere with the reaction of +baryta, but still does not destroy its color. + +(_g._) _Phosphoric Acid._--The phosphates give a green color to the +oxidation flame, especially when they are moistened with sulphuric +acid. This is best shown with the platinum forceps. The green of +phosphoric, or the phosphates, is much less intense than that of the +borates or boracic acid, but yet the reaction is a certain one, and is +susceptible of considerable delicacy, either with the forceps, or +still better upon platinum wire. Sulphuric acid is a great aid to the +development of the color, especially if other salts be present which +would be liable to hide the color of the phosphoric acid. In this +reaction with phosphates, the water should be expelled from them +previous to melting them with sulphuric acid. They should likewise be +pulverized. Should soda be present it will only exhibit its peculiar +color after the phosphoric acid shall have been expelled; therefore, +the green color of the phosphoric acid should be looked for +immediately upon submitting the phosphate to heat. + +(_h._) _Molybdic Acid._--If this acid or the oxide of molybdenum be +exposed upon a platinum wire to the point of the reduction flame, a +bright green color is communicated to the flame of oxidation. Take a +small piece of the native sulphide of molybdenum, and expose it in the +platinum tongs to the flame referred to above, when the green color +characteristic of this metal will be exhibited. + +(_i._) _Telluric Acid._--If the flame of reduction is directed upon a +small piece of the oxide of tellurium placed upon charcoal, a bright +green color is produced. Or if telluric acid be submitted to the +reduction flame upon the loop of a platinum wire, it communicates to +the outer flame the bright green of tellurium. If the sublimate found +upon the charcoal in the first experiment be submitted to the blowpipe +flame, the green color of tellurium is produced while the sublimate is +volatilized. If selenium be present the green color is changed to a +deep blue one. + + +D. YELLOW. + +The salts of soda all give a bright yellow color when heated in the +platinum loop in the reduction flame. This color is very persistent, +and will destroy the color of almost any other substance. Every +mineral of which soda is a constituent, give this bright orange-yellow +reaction. Even the silicate of soda itself imparts to the flame of +oxidation the characteristic yellow of soda. + + +E. RED. + +(_a._) _Strontia._--Moisten a small piece of the chloride of +strontium, put it in the platinum forceps and submit it to the flame +of reduction, when the outer flame will become colored of an intense +red. If the salt of strontia should be a soluble one, the reaction is +of a deeper color than if an insoluble salt is used, while the color +is of a deeper crimson if the salt is moistened. If the salt be a +soluble one, it should be moistened and dipped into the flame, while +if it be an insoluble salt, it should be kept dry and exposed beyond +the point of the flame. The carbonate of strontia should be moistened +with hydrochloric acid instead of water, by which its color similates +that of the chloride of strontium when moistened with water. In +consequence of the decided red color which strontia communicates to +flame, it is used by pyrotechnists for the purpose of making their +"crimson fire." + +(_b._) _Lithia._--The color of the flame of lithia is slightly +inclined to purple. The chloride, when placed in the platinum loop, +gives to the outer flame a bright red color, sometimes with a slight +tinge of purple. Potash does not prevent this reaction, although it +may modify it to violet; but the decided color of soda changes the red +of lithia to an orange color. If much soda be present, the color of +the lithia is lost entirely. The color of the chloride of lithium may +be distinctly produced before the point of the blue flame, and its +durability may be the means of determining it from that of lithium, +as the latter, under the same conditions, is quite evanescent. The +minerals which contain lithia, frequently contain soda, and thus the +latter destroys the color of the former. + +(_c._) _Potash._--The salts of potash, if the acid does not interfere, +give a purplish-red color before the blowpipe; but as the color is +more discernibly a purple, we have classed it under that color. + +(_d._) _Lime._--The color of the flame of lime does not greatly differ +from that of strontia, with the exception that it is not so decided. +Arragonite and calcareous spar, moistened with hydrochloric acid, and +tried as directed for strontia, produce a red light, not unlike that +of strontia. The chloride of calcium gives a red tinge, but not nearly +so decided as the chloride of strontium. The carbonate of lime will +produce a yellowish flame for a while, until the carbonic acid is +driven off, when the red color of the lime may be discerned. + +If the borate or phosphate of lime be used, the green color of the +acids predominates over the red of the lime. Baryta also destroys the +red color of the lime, by mixing its green color with it. There is but +one silicate of lime which colors the flame red, it is the variety +termed tabular spar. + + +5. EXAMINATIONS IN THE BORAX BEAD. + + +In order to examine a substance in borax, the loop of the platinum +wire should, after being thoroughly cleaned, and heated to redness, be +quickly dipped into the powdered borax, and then quickly transferred +to the flame of oxidation, and there fused. If the bead is not large +enough to fill the loop of the wire, it must be subjected again to the +same process. By examining the bead, both when hot and cold, by +holding it up against the light, it can be soon ascertained whether it +is free from dirt by the transparency, or the want of it, of the bead. + +In order to make the examination of a substance, the bead should be +melted and pressed against it, when enough will adhere to answer the +purpose. This powder should then be fused in the oxidation flame until +it mixes with, and is thoroughly dissolved by the borax bead. + +The principal objects to be determined now are: the color of the borax +bead, both when heated and when cooled; also the rapidity with which +the substance dissolves in the bead, and if any gas is eliminated. + +If the color of the bead is the object desired, the quantity of the +substance employed must be very small, else the bead will be so deeply +colored, as in some cases to appear almost opaque, as, for instance, +in that of cobalt. Should this be the case, then, while the bead is +still red hot, it should be pressed flat with the forceps; or it may, +while soft, be pulled out to a thin thread, whereby the color can be +distinctly discovered. + +Some bodies, when heated in the borax bead, present a clear bead both +while hot and cold; but if the bead be heated with the intermittent +flame, or in the flame of reduction, it becomes opalescent, opaque or +milk-white. The alkaline earths are instances of this kind of +reaction, also glucina oxide of cerium, tantalic and titanic acids, +yttria and zirconia. But if a small portion of silica should be +present, then the bead becomes clear. This is likewise the case with +some silicates, provided there be not too large a quantity present, +that is: over the quantity necessary to saturate the borax, for, in +that case, the bead will be opaque when cool. + +If the bead be heated on charcoal, a small tube or cavity must be +scooped out of the charcoal, the bead placed in it, and the flame of +reduction played upon it. When the bead is perfectly fused, it is +taken up between the platinum forceps and pressed flat, so that the +color may be the more readily discerned. This quick cooling also +prevents the protoxides, if there be any present, from passing into a +higher degree of oxidation. + +The bead should first be submitted to the oxidation flame, and any +reaction carefully observed. Then the bead should be submitted to the +flame of reduction. It must be observed that the platinum forceps +should not be used when there is danger of a metallic oxide being +reduced, as in this case the metal would alloy with the platinum and +spoil the forceps. In this case charcoal should be used for the +support. If, however, there be oxides present which are not reduced by +the borax, then the platinum loop may be used. Tin is frequently used +for the purpose of enabling the bead to acquire a color for an oxide +in the reducing flame, by its affinity for oxygen. The oxide, thus +being reduced to a lower degree of oxidation, imparts its peculiar +tinge to the bead as it cools. + +The arsenides and sulphides, before being examined, should be roasted, +and then heated with the borax bead. The arsenic of the former, it +should be observed, will act on the glass tube in which the +sublimation is proceeding, if the glass should contain lead. + +It should be recollected that earths, metallic oxides, and metallic +acids are soluble in borax, except those of the easily reducible +metals, such as platinum or gold, or of mercury, which too readily +vaporize. Also the metallic sulphides, after the sulphur has been +driven off. Also the salts of metals, after their acids are driven off +by heat. Also the nitrates and carbonates, after their acids are +driven off during the fusion. Also the salts of the halogens, such as +the chlorides, iodides, bromides, etc., of the metals. Also the +silicates, but with great tardiness. Also the phosphates and borates +that fuse in the bead without suffering decomposition. The metallic +sulphides are insoluble in borax, and many of the metals in the pure +state. + +There are many substances which give clear beads with borax both while +hot and cold, but which, upon being heated with the intermittent +oxidation flame, become enamelled and opaque. The intermittent flame +may be readily attained, not by varying the force of the air from the +mouth, but by raising and depressing the bead before the point of the +steady oxidating flame. The addition of a little nitrate of potash +will often greatly facilitate the production of a color, as it +oxidizes the metal. The hot bead should be pressed upon a small +crystal of the nitrate, when the bead swells, intumesces, and the +color is manifested in the surface of the bead, + + +6. EXAMINATIONS IN MICROCOSMIC SALT. + + +Microcosmic salt is a better flux for many metallic oxides than borax, +as the colors are exhibited in it with more strength and character. +Microcosmic salt is the phosphate of soda and ammonia. When it is +ignited it passes into the biphosphate of soda, the ammonia being +driven off. This biphosphate of soda possesses an excess of phosphoric +acid, and thus has the property of dissolving a great number of +substances, in fact almost any one, with the exception of silica. If +the substances treated with this salt consist of sulphides or +arsenides, the bead must be heated on charcoal. But if the substance +experimented upon consists of earthly ingredients or metallic oxides, +the platinum wire is the best. If the latter is used a few additional +turns should be given to the wire in consequence of the greater +fluidity of the bead over that of borax. The microcosmic salt bead +possesses the advantage over that of borax, that the colors of many +substances are better discerned in it, and that it separates the +acids, the more volatile ones being dissipated, while the fixed ones +combine with a portion of the base equally with the phosphoric acid, +or else do not combine at all, but float about in the bead, as is the +case particularly with silicic acid. Many of the silicates give with +borax a clear bead, while they form with microcosmic salt an +opalescent one. + +It frequently happens, that if a metallic oxide will not give its +peculiar color in one of the flames, that it will in the other, as the +difference in degree with which the metal is oxidized often determines +the color. If the bead is heated in the reducing flame, it is well +that it should be cooled rapidly to prevent a reoxidation. Reduction +is much facilitated by the employment of metallic tin, whereby the +protoxide or the reduced metal may be obtained in a comparatively +brief time. + +The following tables, taken from Plattner and Sherer, will present the +reactions of the metallic oxides, and some of the metallic acids, in +such a clear light, that the student cannot very easily be led astray, +if he gives the least attention to them. It frequently happens that a +tabular statement of reactions will impress facts upon the memory when +long detailed descriptions will fail to do so. It is for this purpose +that we subjoin the following excellent tables. + + * * * * * + + +TABLE I. + + + A. BORAX. + 1. Oxydizing flame. + 2. Reducing " + + B. MICROCOSMIC SALT. + 1. Oxydizing flame. + 2. Reducing " + + +A. BORAX + +1. Oxydizing flame + +-------------------------------------------------------------------------- +Color of Bead. +--+----------------------------------------------------------------------- + | Substances which produce this color + +--------------------------------------+-------------------------------- + | in the hot bead. | in the cold bead. +--+--------------------------------------+-------------------------------- +Colorless +-----------------------------------------+-------------------------------- + | Silica \ | Silica + | Alumina \ | Alumina _ + | Oxide of Tin | | Oxide of Tin \ + | Telluric Acid | | Telluric Acid \ + | Baryta | | Baryta \ + | Strontia | | Strontia | + | Lime | | Lime | + | Magnesia | | Magnesia | + | Glucina | In all | Glucina | + | Yttria } proportions. | Yttria | + | Zirconia | | Zirconia | + | Thoria | | Thoria |With + | Oxide of Lanthanum | | Oxide of Lanthanum |intermittent + | | | " " Silver }flame + | Tantalic Acid | | Tantalic Acid |opaque + | Niobic " | | Niobic " |white. + | Pelopic " / | Pelopic " | + | Titanic " _/ | Titanic " | + | _ | | + | Tungstic " \ In small | Tungstic " | + | Molybdic " \ quantity | Molybdic " | + | Oxide of Zinc | only. | Oxide of Zinc / + | " " Cadmium } | " " Cadmium_/ + | " " Lead | In large | " " Lead + | " " Bismuth / quantity | " " Bismuth + | " " Antimony / yellow. | " " Antimony +--+-----------+--------------------------+-------------------------------- +Yellow, orange-red and reddish-brown. +--+-----------+--------------------------+-------------------------------- + | _ | + | Titanic Acid, yellow \ | + | Tungstic Acid, yellow \ | + | Molybdic Acid, dark yellow|when in | + | Oxide of Zinc, pale-yellow|large | + | Oxide of Cadmium, }quantity. | + | pale-yellow |Otherwise | + | Oxide of Lead, yellow |colorless.| + | Oxide of Bismuth, orange / | + | Oxide of Antimony, yellow/ | + | Oxide of Cerium, red | Oxide of Cerium with interm. + | Oxide of Iron, dark red | flame opaque white. + | Oxide of Uranium, red | Oxide of Iron, yellow + | Oxide of Silver | Oxide of Uranium with interm. + | | flame opaque yellow. + | | Oxide of Silver in large + | | proportion, with interm. + | | flame yellow. + | Vanadic Acid, yellow | Vanadic Acid, yellow. + | Oxide of Chromium, dark-red | Oxide of Nickel, + | | reddish-brown. + | | Oxide of Manganese, red to + | | violet. +--+--------------------------------------+-------------------------------- +Violet or Amethyst. +--+--------------------------------------+-------------------------------- + | Oxide of Nickel | + | " " Manganese | Oxide of Didymium. + | " " Didymium | +--+--------------------------------------+-------------------------------- +Blue. +--+--------------------------------------+-------------------------------- + | Oxide of Cobalt | Oxide of Cobalt. + | | " Copper, blue to + | | greenish-blue. +--+--------------------------------------+-------------------------------- +Green. +--+--------------------------------------+-------------------------------- + | Oxide of Copper | Oxide of Chromium, with + | | yellowish tinge. +--+--------------------------------------+-------------------------------- + + +A. BORAX + +2. Reducing flame + +--+--------------------------------------+-------------------------------- +Color of Bead. +--+----------------------------------------------------------------------- + | Substances which produce this color + +--------------------------------------+-------------------------------- + | in the hot bead. | in the cold bead. +--+--------------------------------------+-------------------------------- +Colorless +--+--------------------------------------+-------------------------------- + | Silica | Silica + | Alumina | Alumina + | Oxide of Tin | Oxide of Tin _ + | Baryta | Baryta \ + | Strontia | Strontia \ + | Lime | Lime | + | Magnesia | Magnesia |With + | Glucina | Glucina |intermittent + | Yttria | Yttria }flame + | Zirconia | Zirconia |opaque-white. + | Thoria | Thoria only when | + | | saturated | + | Oxide of Lanthanum | Oxide of Lanthanum | + | " " Cerium | " " Cerium / + | Tantalic Acid | Tantalic Acid _/ + | Oxide of Didymium | Oxide of Didymium + | " " Manganese | " " Manganese + | _ | _ + | Niobic Acid \ In small | Niobic Acid \ In small + | Pelopic " } proportions. | Pelopic " } proportions. + | _/ | _/ + | _ | _ + | Oxide of Silver \ | Oxide of Silver \ After + | " " Zinc \ After long | " " Zinc \ long + | " " Cadmium | continued | " " Cadmium | continued + | " " Lead } blowing. | " " Lead } blowing. + | " " Bismuth | Otherwise | " " Bismuth | Otherwise + | " " Antimony| grey. | " " Antimony | grey. + | " " Nickel / | " " Nickel / + | Telluric Acid _/ | Telluric Acid _/ +--+--------------------------------------+-------------------------------- +Yellow to brown. +--+--------------------------------------+-------------------------------- + | Titanic Acid | Titanic Acid. + | Tungstic " | Tungstic " + | Molybdic " | Molybdic " + | Vanadic " | +--+--------------------------------------+-------------------------------- +Blue. +--+--------------------------------------+-------------------------------- + | Oxide of Cobalt. | Oxide of Cobalt. + | | Titanic Acid with intermittent + | | flame opaque-blue. +--+--------------------------------------+-------------------------------- +Green. +--+--------------------------------------+-------------------------------- + | Oxide of Iron | Oxide of Iron, bottle-green. + | " " Uranium | Oxide of Uranium, bottle- + | " " Chromium | green. + | | Oxide of Chromium, emerald- + | | green. + | | Vanadic Acid, emerald-green. +--+--------------------------------------+-------------------------------- +Opaque-grey. (The opacity generally becomes distinct during cooling.) +--+--------------------------------------+-------------------------------- + | _ | + | Oxide of Silver \ | Oxide of Silver._ + | " " Zinc \ After | " " Zinc \ After + | " " Cadmium | short | " " Cadmium \short + | " " Lead } blowing. | " " Lead |blowing. + | " " Bismuth | Otherwise | " " Bismuth }Otherwise + | " " Antimony| colorless. | " " Antimony |colorless. + | " " Nickel / | " " Nickel / + | Telluric Acid _/ | Telluric Acid _/ + | _ | _ + | Niobic Acid \ After long | Niobic Acid\ After long + | Pelopic " | continued blowing | Pelopic " | continued + | } and in | } blowing and + | | considerable | | in considerable + | _/ proportion. | _/ proportion. + | | +--+--------------------------------------+-------------------------------- +Opaque red and reddish-brown. +--+--------------------------------------+-------------------------------- + | Oxide of Copper | Oxide of Copper. +--+--------------------------------------+-------------------------------- + + +B. MICROCOSMIC SALT. + +1. Oxydizing flame. + +--+--------------------------------------+-------------------------------- +Color of Bead. +--+----------------------------------------------------------------------- + | Substances which produce this color + +--------------------------------------+-------------------------------- + | in the hot bead. | in the cold bead. +--+--------------------------------------+-------------------------------- +Colorless +--+--------------------------------------+-------------------------------- + | _ | + | Silica (only \ | Silica + | slightly soluble)\ | + | Alumina | | Alumina + | Oxide of Tin | | Oxide of Tin _ + | Telluric Acid | | Telluric Acid \ + | Baryta | | Baryta \ + | Strontia | | Strontia |With + | Lime | In all | Lime |intermittent + | Magnesia } proportions. | Magnesia }flame + | Glucina | | Glucina |opaque + | Yttria | | Yttria |white. + | Zirconia | | Zirconia | + | Thoria | | Thoria / + | Oxide of Lanthanum | | Oxide of Lanthanum/ + | | | " " Cerium + | Niobic Acid / | Niobic Acid + | Pelopic " _/ | Pelopic " + | Tantalic " | Tantalic " + | Titanic " | Titanic " + | Tungstic " _ | Tungstic " + | Oxide of Zinc \ In small | Oxide of Zinc + | " " Cadmium \ quantity only. | " " Cadmium + | " " Lead } In large | " " Lead + | " " Bismuth | quantity | " " Bismuth + | " " Antimony / yellow. | " " Antimony + | _/ | +--+--------------------------------------+-------------------------------- +Yellow, orange, red and brown. +--+--------------------------------------+-------------------------------- + | Tantalic Acid _ | + | Titanic " \ | + | Tungstic " | | + | Oxide of Zinc | In large | + | " " Cadmium } quantity. | + | " " Lead | | + | " " Bismuth | | + | " " Antimony _/ | + | " " Silver | Oxide of Silver. + | " " Cerium | + | " " Iron | Oxide of Iron. + | " " Nickel | " " Nickel. + | " " Uranium | " " Uranium, + | | yellowish-green. + | Vanadic Acid | Vanadic Acid. + | Oxide of Chromium | +--+--------------------------------------+-------------------------------- +Violet or Amethyst. +--+--------------------------------------+-------------------------------- + | Oxide of Manganese | Oxide of Manganese. + | " " Didymium | " " Didymium. +--+--------------------------------------+-------------------------------- +Blue. +--+--------------------------------------+-------------------------------- + | Oxide of Cobalt | Oxide of Cobalt + | | Oxide of Copper, to + | | greenish-blue. +--+--------------------------------------+-------------------------------- +Green. +--+--------------------------------------+-------------------------------- + | Molybdic Acid, yellowish-green | Molybdic Acid, yellowish-green. + | Oxide of Copper | Oxide of Uranium, + | | yellowish-green. + | | Oxide of Chromium, + | | emerald-green. +--+--------------------------------------+-------------------------------- + + +B. MICROCOSMIC SALT. + +2. Reducing flame. + +--+--------------------------------------+-------------------------------- +Color of Bead. +--+----------------------------------------------------------------------- + | Substances which produce this color + +--------------------------------------+--------------------------------- + | in the hot bead. | in the cold bead. +--+--------------------------------------+-------------------------------- +Colorless +--+--------------------------------------+-------------------------------- + | Silica (only slightly soluble) | Silica (only slightly soluble). + | Alumina | Alumina. + | Oxide of Tin | Oxide of Tin. _ + | Baryta | Baryta \ + | Strontia | Strontia \ + | Lime | Lime | + | Magnesia | Magnesia |With an + | Glucina | Glucina }intermittent + | Yttria | Yttria |flame + | Zirconia | Zirconia |opaque- + | Thoria | Thoria only when |white. + | | saturated / + | Oxide of Lanthanum | Oxide of Lanthanum/ + | " " Cerium | " " Cerium. + | " " Didymium | " " Didymium. + | " " Manganese | " " Manganese. + | Tantalic Acid _ | Tantalic Acid. + | Oxide of Silver \ | Oxide of Silver _ + | " " Zinc \ | " " Zinc \ After + | " " Cadmium | After long | " " Cadmium \ long + | " " Lead } continued | " " Lead | continued + | " " Bismuth | blowing. | " " Bismuth } blowing. + | " " Antimony | Otherwise grey. | " " Antimony | Otherwise + | " " Nickel / | " " Nickel / grey. + | Telluric Acid _/ | Telluric Acid _/ +--+--------------------------------------+-------------------------------- +Yellow, red, and brown. +--+--------------------------------------+-------------------------------- + | Oxide of Iron, red | Oxide of Iron. + | Titanic Acid, yellow | + | Pelopic Acid, brown | Pelopic Acid. + | Ferruginous Titanic Acid, blood red | Ferruginous Titanic Acid. + | " Niobic " " | " Niobic " + | " Pelopic " " | " Pelopic " + | " Tungstic " " | " Tungstic " + | Vanadic Acid, brownish | + | Oxide of Chromium, reddish | +--+--------------------------------------+-------------------------------- +Violet or Amethyst. +--+--------------------------------------+-------------------------------- + | Niobic Acid in large proportion | Niobic Acid in large proportion. + | | Titanic Acid. +--+--------------------------------------+-------------------------------- +Blue. +--+--------------------------------------+-------------------------------- + | Oxide of Cobalt | Oxide of Cobalt. + | Tungstic Acid | Tungstic Acid. + | Niobic Acid in very large proportion.| Niobic Acid in very large + | | proportion. +--+--------------------------------------+-------------------------------- +Green. +--+--------------------------------------+-------------------------------- + | Oxide of Uranium | Oxide of Uranium. + | Molybdic Acid | Molybdic Acid. + | | Vanadic " + | | Oxide of Chromium. +--+--------------------------------------+-------------------------------- +Opaque-grey. (The opacity generally becomes distinct during cooling.) +--+--------------------------------------+-------------------------------- + | Oxide of Silver | Oxide of Silver. + | " " Zinc | " " Zinc. + | " " Cadmium | " " Cadmium. + | " " Lead | " " Lead. + | " " Bismuth | " " Bismuth. + | " " Antimony | " " Antimony. + | " " Nickel | " " Nickel. + | Telluric Acid | Telluric Acid. +--+--------------------------------------+-------------------------------- +Opaque-red and reddish brown. +--+--------------------------------------+-------------------------------- + | Oxide of Copper | Oxide of Copper. +--+--------------------------------------+-------------------------------- + + * * * * * + + +TABLE II. + + +Metallic Oxides + +1. Oxide of Cerium, C^{2}O^{3}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Dissolves into a red or dark yellow glass (similar to that + produced by iron). During cooling, the color diminishes in the + intensity and becomes finally yellow. If much oxide be dissolved, + an opaque bead may be obtained with an intermittent flame, and a + still larger quantity renders it opaque spontaneously. + + in the reducing flame. + + The color of the bead becomes paler, so that a bead, which is + yellow in the oxidizing flame, is rendered colorless. With a + large quantity of oxide the bead becomes white and crystalline + on cooling. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + As with borax. During the process of cooling the color entirely + disappears. + + in the reducing flame. + + Both, when hot and cold, the bead is colorless, by which + character oxide of cerium may be distinguished from oxide of + iron. The glass remains clear even when containing a large + quantity of the oxide. + + * * * * * + +2. Oxide of Lanthanum, LaO. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Dissolves into a colorless glass, which, when sufficient oxide + is present, may be rendered opaque with an intermittent flame, + and becomes so spontaneously on cooling, when a still larger + amount is dissolved. + + in the reducing flame. + + As in the oxidizing flame. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + As with borax. + + in the reducing flame. + + No reaction. + + * * * * * + +3. Oxide of Didymium, DO. + + Behavior with Borax on Platinum wire + + in the oxidizing flame: + + Dissolves to a clear dark amethystine glass. + + in the reducing flame. + + No reaction. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + As with borax. + + in the reducing flame. + + No reaction. + + * * * * * + +4. Oxide of Manganese, Mn^{2}O^{3}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Affords an intense amethyst color, which on cooling becomes + violet. A large quantity of the oxide produces an apparently + black bead, which however, if pressed flat, is seen to be + transparent. + + in the reducing flame. + + The colored bead becomes colorless. With a large amount of the + oxide, this reaction is best obtained upon charcoal, and is + facilitated by the addition of tin foil. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + With a considerable quantity of oxide an amethyst color is + obtained, but never so dark as in borax. With but little oxide a + colorless bead is obtained, in which, however, the + amethyst-color may be brought out by adding a little nitre. + While the bead is kept fused, it froths and gives off bubbles of + gas. + + in the reducing flame. + + The colored bead immediately loses its color, either on platinum + wire or on charcoal. After the reduction the fluid bead remains + still. + + * * * * * + +5. Oxide of Iron, Fe^{2}O^{3}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + With a small proportion of oxide, the glass is of a yellow + color, while warm, and colorless when cold; with a larger + proportion, red, while warm, and yellow, when cold; and with a + still larger amount, dark-red, while warm, and dark-yellow, when + cold. + + in the reducing flame. + + Treated alone on platinum wire, the glass becomes of a + bottle-green color (F^{3}O^{4}), and if touched with tin, it + becomes of a pale sea-green. On charcoal with tin, it assumes at + first a bottle-green color, which by continued blowing changes + to a sea-green (FeO). + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + With a certain amount of oxide, the glass is of a yellowish-red + color, which on cooling changes to yellow, then green, and + finally becomes colorless. With a large addition of oxide, the + color is, when warm, dark red, and passes, while cooling, into + brownish-red, dark green, and finally brownish-red. During the + cooling process, the colors change more rapidly than with borax. + + in the reducing flame. + + With a small proportion of oxide there is no reaction. With a + larger amount the bead is red, while warm, and becomes on + cooling successively yellow, green, and russet. With the + addition of tin the glass becomes, during cooling, first green + and then colorless. + + * * * * * + +6. Oxide of Cobalt, CoO. + + Behavior with Borax on Platinum wire + + in the oxidizing flame: + + Colors the glass of an intense smalt blue both whilst hot and + when cold. When much oxide is present, the color is so deep as + to appear black. + + in the reducing flame: + + As in the oxidizing flame. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + As with borax, but less intensively colored. During cooling the + color becomes somewhat paler. + + in the reducing flame. + + As in the oxidizing flames. + + * * * * * + +7. Oxide of Nickel, NiO. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Colors intensely. A small amount of oxide affords a glass which, + while warm, is violet, and becomes of a pale reddish-brown on + cooling. A larger addition produces a dark violet color in the + warm and reddish-brown in the cold bead. + + in the reducing flame. + + The oxide is reduced and the metallic particles give the bead a + turbid grey appearance. If the blast be continued the metallic + particles fall together without fusing, and the glass becomes + colorless. This reaction is readily obtained with tin upon + charcoal, and the reduced nickel fuses to a bead with the tin. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + Dissolves into a reddish glass which becomes yellow on cooling. + With a large addition of the oxide, the glass is brownish while + hot, and orange when cold. + + in the reducing flame. + + On platinum wire the nickeliferous bead undergoes no change. + Treated with tin upon charcoal, it becomes at first opaque and + grey, and after long continued blowing the reduced nickel forms + a bead, and the glass remains colorless. + + * * * * * + +8. Oxide of Zinc, ZnO. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Dissolves easily into a clear colorless glass, which, when much + oxide is present, may be rendered opaque and flocculent by an + intermittent flame, and becomes so spontaneously with a still + larger addition. When a considerable quantity is dissolved, a + glass is obtained which is pale yellow, while hot, and colorless + when cold. + + in the reducing flame. + + On platinum wire the saturated glass becomes at first opaque and + grey, but by a sustained blast is again rendered clear. On + charcoal the oxide is gradually reduced; the metal is + volatilized and in crusts the charcoal with oxide. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + As with borax. + + in the reducing flame. + + As with borax. + + * * * * * + +9. Oxide of Cadmium, CdO. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + When in very large proportion, dissolves to a clear yellow + glass, which becomes nearly colorless on cooling. When the oxide + is present in any considerable quantity, the glass can be + rendered opaque with an intermittent flame, and, with a larger + addition, it becomes so spontaneously on cooling. + + in the reducing flame. + + Upon charcoal ebullition takes place and the oxide is reduced. + The metallic cadmium is volatilized and incrusts the charcoal + with its characteristic deep yellow oxide. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + When in very large proportion dissolves to a clear glass, having + a yellow tinge, while hot, which disappears on cooling, and when + perfectly saturated, becomes milk-white. + + in the reducing flame. + + On charcoal the oxide is slowly and imperfectly reduced. The + reduced metal forms the characteristic incrustation on the + charcoal, but the is thin and does not exhibit its color clearly + until quite cold. The addition of tin hastens the reaction. + + * * * * * + +10. Oxide of Lead, PbO. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Dissolves readily to a clear yellow glass, which loses its color + upon cooling, and when containing much oxide can be rendered + dull under an intermittent flame. With a still larger addition + of oxide it becomes opaline yellow on cooling. + + in the reducing flame. + + The plumbiferous glass spreads out on charcoal, becomes turbid, + bubbles up, until the whole of the oxide is reduced, when it + again becomes clear. It is, however, difficult to bring the lead + together into a bead. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + As with borax, but a larger addition of oxide, required to + produce a yellow color in the warm bead. + + in the reducing flame. + + On charcoal the plumbiferous glass becomes grey and dull. With + an over dose of oxide a part is volatilized and forms an + incrustation on the charcoal beyond the bead. The addition of + tin does not render the glass opaque, but somewhat more dull and + grey than in its absence. + + * * * * * + +11. Oxide of Tin, SnO^{2}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + In small quantity dissolves slowly into a clear colorless glass, + which, when cold, remains clear, and cannot be rendered opaque + with an intermittent flame. If a saturated bead, which has been + allowed to cool, be reheated to incipient redness, it loses its + rounded form and exhibits imperfect crystallization. + + in the reducing flame. + + A glass containing but little oxide undergoes no change. If much + of the latter be present, a part may be reduced upon charcoal. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + In small quantity dissolves very slowly to a colorless glass, + which remains clear on cooling. + + in the reducing flame. + + The glass undergoes no change, either on charcoal or platinum wire. + + * * * * * + +12. Oxide of Bismuth, BiO^{3}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Dissolves readily to a clear glass which with a small amount of + the oxide is yellow, while warm, and becomes colorless on + cooling. With a larger addition, the glass is, in the hot state, + of a deep orange color, which changes to yellow and finally + becomes opaline in process of cooling. + + in the reducing flame. + + A glass becomes at first grey and turbid, then begins to + effervesce, which action continues during the reduction of the + oxide, and it finally becomes perfectly clear. If tin be added, + the glass becomes at first grey from the reduced bismuth, but, + when the metal is collected into a bead, the glass is again + clear and colorless. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + Dissolves in small quantity to a clear colorless glass. A larger + addition affords a glass which, while warm, is yellow, and + becomes colorless on cooling. When in sufficient proportion the + glass may be rendered opaque under an intermittent flame, and a + still larger addition of oxide renders the bead spontaneously + opaque on cooling. + + in the reducing flame. + + On charcoal, and especially with the addition of tin, the glass + remains colorless and clear, while warm, but becomes on cooling + of a dark grey color and opaque. + + * * * * * + +13. Oxide of Uranium, U^{2}O^{3}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Behaves similarly to oxide of iron, with the exception that the + color of the former is somewhat paler. When sufficiently + saturated, the glass may be rendered of an opaque yellow by an + intermittent flame. + + in the reducing flame. + + Affords the same color as the oxide of iron. The green glass + obtained in this flame, if sufficiently saturated, can be + rendered black by an intermittent flame, but it has under these + circumstances no enameline appearance. On charcoal, with the + addition of tin, the glass takes a dark green color. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + Dissolves to a clear yellow glass, which assumes a + yellowish-green color on cooling. + + in the reducing flame. + + The glass assumes a beautiful green color, which becomes more + brilliant as the bead cools. The addition of tin upon charcoal + produces no further change. + + * * * * * + +14. Oxide of Copper, CuO. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Produces an intense coloration. If in small quantity, the glass + is green, while warm, and becomes blue on cooling. If in large + proportion, the green color is so intense as to appear black. + When cool, this becomes paler, and changes to a greenish blue. + + in the reducing flame. + + If not too saturated, the cupriferous glass soon becomes nearly + colorless, but immediately on solidifying assumes a red color + and becomes opaque. By long continued blowing on charcoal, the + copper in the bead is reduced and separates out as a small + metallic bead, leaving the glass colorless. With the addition of + tin, the glass becomes of an opaque dull-red on cooling. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + With an equal proportion of oxide, this salt is not so strongly + colored as borax. A small amount imparts a green color in the + warm and a blue in the cold. With a very large addition of + oxide, the glass is opaque in the hot state, and after cooling + of a greenish-blue. + + in the reducing flame. + + A tolerably saturated glass assumes a dark green color under a + good flame, and on cooling becomes of an opaque brick-red, the + moment it solidifies. A glass containing but a small proportion + of the oxide becomes equally red and opaque on cooling, if + treated with tin upon charcoal. + + * * * * * + +15. Oxide of Mercury, HgO. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + No reaction. + + in the reducing flame. + + No reaction. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + No reaction. + + in the reducing flame. + + No reaction. + + * * * * * + +16. Oxide of Silver, AgO. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + The oxide is partly dissolved and partly reduced. In small + quantity, it colors the glass yellow while warm, the color + disappearing on cooling. In larger quantity, the glass is yellow + while warm, but during cooling becomes paler to a certain point, + and then again deeper. If reheated slightly, the glass becomes + opalescent. + + in the reducing flame. + + On charcoal the argentiferous glass becomes at first grey from + the reduced metal, but afterwards, when the silver is collected + into a bead, it becomes clear and colorless. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + Both the oxide and the metal afford a yellowish glass, which, + when containing much oxide becomes opaline, exhibiting a yellow + color by daylight and a red one by artificial light. + + in the reducing flame. + + As in borax. + + * * * * * + + +17. Oxide of Platinum, PtO^{2}. +18. Oxide of Palladium, PdO^{2}. +19. Oxide of Rhodium, R^{2}O^{3}. +20. Oxide of Iridium, Ir^{2}O^{3}. +21. Oxide of Ruthenium, Ru^{2}O^{9}. +22. Oxide of Osmium OsO^{2}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Are reduced without being dissolved. The reduced metal, being + infusible, cannot however be collected into a bead. + + in the reducing flame. + + As in the oxidizing flame. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + As in borax. + + in the reducing flame. + + As in borax. + + * * * * * + +23. Oxide of Gold, Au^{2}O^{3}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Is reduced without being dissolved and can be collected into a + bead on charcoal. + + in the reducing flame. + + As in the oxidizing flame. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + As in borax. + + in the reducing flame. + + As in borax. + + * * * * * + +24. Titanic Acid, TiO^{2} + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Dissolves readily to a clear glass which, when but little acid + is present, is colorless, but when in larger proportion, yellow, + and, on cooling, colorless. When sufficiently saturated, it may + be rendered opaque with an intermittent flame, and with a still + larger addition of the acid becomes so spontaneously on cooling. + + in the reducing flame. + + In small proportion, it renders the glass yellow in larger + quantity dark-yellow or brown. A saturated bead assumes a + blue enamel-like appearance under an intermittent flame. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + Dissolves readily to a clear glass, which, when sufficiently + saturated, is yellow white hot, and becomes colorless on + cooling. + + in the reducing flame. + + The glass obtained in the oxidizing glame becomes yellow in the + hot state, but on cooling assumes a beautiful violet color. If + too saturated, this color is so deep as to appear opaque, but is + not enameline. If the titanic acid contains iron, the glass + becomes on cooling of a brownish-yellow or red color. The + addition of tin neutralizes the iron, and the glass then becomes + violet. + + * * * * * + +25. Tantalic Acid, TaO^{3}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Dissolves readily to a clear colorless glass, which, when + sufficiently saturated, may be rendered opaque with an + intermittent flame, and with a larger addition of the acid + becomes spontaneously enameline on cooling. + + in the reducing flame. + + As in the oxidizing flame. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + Dissolves readily to a clear glass, which, when it contains a + large proportion of the acid, is yellow while warm, but becomes + colorless on cooling. + + in the reducing flame. + + The glass obtained in the oxidizing flame undergoes no change, + nor does it, according to _H. Rose_, alter by the addition of + sulphate of iron. + + * * * * * + +26. Niobic Acid, Ni^{2}O{3} + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Behaves in a similar manner to tantalic acid, but the glass + requires a very large dose of the acid to render it opaque under + an intermittent flame. With an increased amount of the acid, the + glass is clear and yellow, while warm, but becomes on cooling + turbid, and when quite cold is white. + + in the reducing flame. + + The glass obtained in the oxidizing flame and which has become + opalescent on cooling, is rendered clear in the reducing flame. + With a larger addition of the acid, it becomes dull, and of a + bluish-grey color on cooling, and a still larger amount of + renders it opaque and bluish grey. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + Dissolves in large quantities to a clear colorless glass. + + in the reducing flame. + + If the acid be not present in too large a proportion, the glass + remains unchanged. An additional amount of the acid renders it + violet, and a still larger quantity affords a beautiful pure + blue color, similar to that produced by tungstic acid. If to + such a bead some sulphate of iron be added, the glass becomes + blood-red. The addition of peroxide of iron renders the glass + deep yellow while warm, the color becomes paler on cooling. + + * * * * * + +27. Pelopic Acid, Pp^{2}O^{3}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Behaves similarly to the preceding. + + in the reducing flame. + + A bead containing sufficient of the acid to render it + spontaneously opaque on cooling, has a greyish color. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + Dissolves even in large quantity to a colorless glass. + + in the reducing flame. + + With sufficient dose of the acid, the bead becomes brown with a + violet tinge. This reaction is readily obtained upon charcoal. + Sulphate of iron renders the bead blood-red. + + * * * * * + +28. Oxide of Antimony, SbO^{3}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Even when in large proportion, dissolves to a clear glass, which + is yellow when warm, but almost entirely loses its color on + cooling. On charcoal, the antimonious acid may be almost + expelled, so that tin produces no further change. + + in the reducing flame. + + A bead, that has only been treated for a short time in the + oxidizing flame, when submitted to the reducing flame becomes + grey and turbid from the reduced antimony. This soon volatizes + and the glass again becomes clear. The addition of tin renders + the glass ash-grey or black, according to the amount of oxide it + contains. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + Dissolves with ebullition to a glass of a pale yellow color + while warm. + + in the reducing flame. + + On charcoal, the saturated glass becomes at first dull, but as + soon as the reduced antimony is volatilized, it again becomes + clear. With tin, the glass is at first rendered grey by the + reduced antimony, but by continued blowing is restored to + clearness. Even when the glass contains but little oxide, tin + produces this reaction. + + * * * * * + +29. Tungstic Acid, WO^{3}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Dissolves readily to a clear colorless glass. In large + proportion it renders the borax yellow, while warm, and with a + still greater addition the bead may be made opaque with an + intermittent flame. If more be then added, this reaction takes + place spontaneously. + + in the reducing flame. + + When the oxide is present in small quantity, the glass undergoes + no change. With a larger proportion, the glass is deep yellow + while warm, and yellowish-brown when cold. This reaction takes + place upon charcoal, with a small quantity of the acid. Tin + produces a dark coloration, when the acid is not present in too + great a quantity. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + Dissolves to a clear glass, which, when saturated, is yellow in + the hot state. + + in the reducing flame. + + The glass is of a pure blue. If the tungstic acid contain iron, + the glass becomes blood-red on cooling, similar to titanic acid. + In this case, tin restores the blue color, or, if iron be in + considerable quantity, renders it green. + + * * * * * + +30. Molydbic Acid, MO^{3}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Dissolves readily and in large quantity. When but little is + dissolved, the glass is yellow while hot and colorless when + cold. When in larger quantity yellow while warm and opaline when + cold, and a further addition of acid renders it yellow when + warm, the color, on cooling, changing first to a pale enamel + blue, and then to an enamel white. + + in the reducing flame. + + The glass, which has been treated in the oxidizing flame, + becomes, when the acid is not present in too large a quantity, + brown, and when in large quantity, perfectly opaque. In a + strong flame, oxide of molybdenum is formed which is visible in + the yellow glass in the form of black flakes. If the glass + appear opaque, it should be flattened with the forceps. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + Dissolves to a clear glass, which, when sufficient acid is + present, is of a yellowish-green color when warm, and becomes + nearly colorless on cooling. On charcoal, the glass becomes + dark, and when cool has a beautiful green color. + + in the reducing flame. + + The glass becomes of a bottle-green color, which on cooling, + changes to a brilliant green, similar to that produced by oxide + of chromium. The reaction on charcoal is precisely similar. Tin + renders the color somewhat darker. + + * * * * * + +31. Vanadic Acid, VaO^{8}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Dissolves to a clear glass, which is colorless when only a small + quantity of acid is present, and yellow when containing a larger + proportion. + + in the reducing flame. + + The yellow color of the glass changes to a brown when warm and a + chrome-green on cooling. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + As with borax. + + in the reducing flame. + + As with borax. + + * * * * * + +32. Oxide of Chromium, Cr^{2}O^{3}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Affords an intense color, but dissolves slowly. A small + proportion colors the glass yellow when warm, and yellowish + green when cold; a larger addition produces a dark red color + when warm, which, on cooling, becomes yellow and finally a + brilliant green with a tinge of yellow. + + in the reducing flame. + + A small quantity of the oxide renders the glass beautifully + green both when warm and when cold. A larger addition changes it + to a darker emerald green. Tin produces no change in the color. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + Dissolves to a clear glass which has a pink tinge while warm, + but on cooling becomes dusky green, and finally brilliantly + green. + + in the reducing flame. + + As in the oxidizing flame, except that the colors are somewhat + darker. Tin produces no further change. + + * * * * * + +33. Arsenious Acid, AsO^{3}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + No reaction. + + in the reducing flame. + + No reaction. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + No reaction. + + in the reducing flame. + + No reaction. + + * * * * * + +34. Tellurous Acid, TeO^{2}. + + Behavior with Borax on Platinum wire + + in the oxidizing flame. + + Dissolves to a clear colorless glass which, when treated on + charcoal, becomes grey and dull from particles of reduced + tellurium. + + in the reducing flame. + + As in the oxidizing flame. + + Behavior with Mic. Salt on Platinum wire + + in the oxidizing flame. + + As with borax. + + in the reducing flame. + + As with borax. + + * * * * * + + +7. EXAMINATIONS WITH CARBONATE OF SODA. + + +The carbonate of soda is pulverized and then kneaded to a paste with +water; the substance to be examined, in fine powder, is also mixed +with it. A small portion of this paste is placed on the charcoal, and +gradually heated until the moisture is expelled, when the heat is +brought to the fusion of the bead, or as high as it can be raised. +Several phenomena will take place, which must be closely observed. +Notice whether the substance fuses with the bead, and if so, whether +there is intumescence or not. Or, whether the substance undergoes +reduction; or, whether neither of these reactions takes place, and, on +the contrary, the soda sinks into the charcoal, leaving the substance +intact upon its surface. If intumescence takes place, the presence of +either tartaric acid, molybdic acid, silicic, or tungstic acid, is +indicated. The silicic acid will fuse into a bead, which becomes clear +when it is cold. Titanic acid will fuse into the bead, but may be +easily distinguished from the silicic acid by the bead remaining +opaque when cold. + +Strontia and baryta will flow into the charcoal, but lime will not. +The molybdic and tungstic acids combine with the soda, forming the +respective salts. These salts are absorbed by the charcoal. If too +great a quantity of soda is used, the bead will be quite likely to +become opaque upon cooling, while, if too small a quantity of soda is +used, a portion of the substance will remain undissolved. These can be +equally avoided by either the addition of soda, or the substance +experimented upon, as may be required. + +As silica and titanic acid are the only two substances that produce a +clear bead, the student, if he gets a clear bead, may almost conclude +that he is experimenting with silica, titanic acid being a rare +substance. When soda is heated with silica, a slight effervescence +will be the first phenomenon noticed. This is the escape of the +carbonic acid of the carbonate of soda, while the silicic acid takes +its place, forming a glass with the soda. As titanic acid will not +act in the same manner as silica, it can be easily distinguished by +its bead not being perfectly pellucid. If the bead with which silica +is fused should be tinted of a hyacinth or yellow color, this may be +attributed to the presence of a small quantity of sulphur or a +sulphate, and this sometimes happens from the fact of the flux +containing sulphate of soda. The following metals, when exposed with +carbonate of soda to the reducing flame, are wholly or partially +reduced, viz. the oxides of all the noble metals, the oxides and acids +of tungsten, molybdenum, arsenic, antimony, mercury, copper, +tellurium, zinc, lead, bismuth, tin, cadmium, iron, nickel, and +cobalt. Mercury and arsenic, as soon as they are reduced, are +dissipated, while tellurium, bismuth, lead, antimony, cadmium, and +zinc, are only partially volatilized, and, therefore, form sublimates +on the charcoal. Those metals which are difficult of reduction should +be fused with oxalate of potassa, instead of the carbonate of soda. +The carbonic oxide formed from the combustion of the acid of this salt +is very efficient in the reduction of these metals. Carbonate of soda +is very efficient for the detection of minute quantities of manganese. +The mixture of the carbonate of soda with a small addition of nitrate +of potassa, and the mineral containing manganese, must be fused on +platinum foil. The fused mass, when cooled, presents a fine blue +color. + + * * * * * + +1. The following minerals, according to Griffin, produce beads with +soda, but do not fuse when heated alone: quartz, agalmatolyte, +dioptase, hisingerite, sideroschilosite, leucite, rutile, +pyrophyllite, wolckonskoite. + +2. The following minerals produce only slags with soda: allophane, +cymophane, polymignite, æschynite, oerstedtite, titaniferous iron, +tantalite, oxides of iron, yttro-tantalite, oxides of manganese, +peroxide of tin (is reduced), hydrate of alumina, hydrate of magnesia, +spinel, gahnite, worthite, carbonate of zinc, pechuran, zircon, +thorite, andalusite, staurolite, gehlenite, chlorite spar, chrome +ochre, uwarowite, chromate of iron, carbonates of the earths, +carbonates of the metallic oxides, basic phosphate of yttria, do. of +alumina, do. of lime, persulphate of iron, sulphate of alumina, +aluminite, alumstone, fluoride of cerium, yttrocerite, topaz, +corundum, pleonaste, chondrodite. + +3. The following minerals produce beads with a small quantity of soda, +but produce slags if too much soda is added: phenakite, pierosmine, +olivine, cerite, cyanite, talc, gadolinite, lithium-tourmaline. + + * * * * * + +1. The following minerals, when fused alone, produce beads. Of these +minerals the following produce beads with soda: the zeolites, +spodumene, soda-spodumene, labrador, scapolite, sodalite (Greenland), +elæolite, mica from primitive lime-stone, black talc, acmite, +krokidolite, lievrite, cronstedtite, garnet, cerine, helvine, +gadolinite, boracic acid, hydroboracite, tincal, boracite, datholite, +botryolite, axinite, lapis lazuli, eudialyte, pyrosmalite, cryolite. + +2. The following minerals produce beads with a small quantity of soda, +but if too much is added they produce slags: okenite, pectolite, red +silicate of manganese, black hydro-silicate of manganese, idocrase, +manganesian garnets, orthite, pyrorthite, sordawalite, sodalite, +fluorspar. + +3. The following minerals produce a slag with soda: brevicite, +amphodelite, chlorite, fahlunite, pyrope, soap-stone (Cornish) red +dichroite, pyrargillite, black potash tourmaline, wolfram, +pharmacolite, scorodite, arseniate of iron, tetraphyline, hetepozite, +uranite, phosphate of iron, do. of strontia, do. of magnesia, +polyhalite, hauyne. + +4. The following metals are reduced by soda: tungstate of lead, +molybdate of lead, vanadate of lead, chromate of lead, vauquelinite, +cobalt bloom, nickel ochre, phosphate of copper, sulphate of lead, +chloride of lead, and chloride of silver. + + * * * * * + +The following minerals fuse on the edges alone, when heated in the +blowpipe flame: + +1. The following produce beads with soda: steatite, meerschaum, +felspar, albite, petalite, nepheline, anorthite, emerald, euclase, +turquois, sodalite (Vesuvius). + +2. The following minerals produce beads with a small quantity of +soda, but with the addition of more produce slags: tabular spar, +diallage, hypersthene, epidote, zoisite. + +3. The following minerals produce slags only with soda: +stilpnosiderite, plombgomme, serpentine, silicate of manganese (from +Piedmont), mica from granite, pimelite, pinite, blue dichroite, +sphenc, karpholite, pyrochlore, tungstate of lime, green soda +tourmaline, lazulite, heavy spar, gypsum. + + * * * * * + +The reactions of substances, when fused with soda in the flame of +oxidation may be of use to the student. A few of them are therefore +given. Silica gives a clear glass. + +The oxide of tellurium and telluric acid gives a clear bead when it is +hot, but white after it is cooled. + +Titanic acid gives a yellow bead when hot. + +The oxide of chromium gives also a clear yellow glass when hot, but is +opaque when cold. + +Molybdic acid gives a clear bead when hot, but is turbid and white +after cooling. + +The oxides and acids of antimony give a clear and colorless bead while +hot, and white after cooling. + +Vanadic acid is absorbed by the charcoal, although it is not reduced. + +Tungstic acid gives a dark yellow clear bead while hot, but is opaque +and yellow when cold. + +The oxides of manganese give to the soda bead a fine characteristic +green color. This is the case with a very small quantity. This +reaction is best exhibited on platinum foil. + +Oxide of cobalt gives to the bead while hot a red color, which, upon +being cooled, becomes grey. + +The oxide of copper gives a clear green bead while hot. + +The oxide of lead gives a clear colorless bead while hot, which +becomes, upon cooling, of a dirty yellow color and opaque. + + * * * * * + +The following metals, when they are fused with soda on charcoal, in +the flame of reduction, produce volatile oxides, and leave an +incrustation around the assay, viz. bismuth, zinc, lead, cadmium, +antimony, selenium, tellurium, and arsenic. + +_Bismuth_, under the reduction flame, yields small particles of metal, +which are brittle and easily crushed. The incrustation is of a flesh +color, or orange, when hot, but gets lighter as it cools. The +sublimate may be driven about the charcoal from place to place, by +either flame, but is finally dissipated. While antimony and tellurium, +in the act of dissipation, give color to the flame, bismuth does not, +and may thus be distinguished from them. + +_Zinc_ deposits an incrustation about the assay, which is yellow while +hot, but fades to white when cold. The reduction flame dissipates this +deposit, but not that of oxidation. All the zinc minerals deposit the +oxide incrustation about the assay, which, when moistened with a +solution of cobalt and heated, changes to green. + +_Lead_ is very easily reduced, in small particles, and may be easily +distinguished by its flattening under the hammer, unlike bismuth. It +leaves an incrustation around the assay resembling that of bismuth, in +the color of it, and in the peculiar manner in which it lies around +the assay. + +_Cadmium_ deposits a dull reddish incrustation around the assay. +Either of the flames dissipate the sublimate with the greatest +readiness. + +_Antimony_ reduces with readiness. At the same time it yields +considerable vapor, and deposits an incrustation around the assay. +This deposit can be driven about on the charcoal by either of the +flames. The flame of reduction, however, produces the light blue color +of the antimony. + +_Selenium_ is deposited on the charcoal as a grey metallic-looking +sublimate, but sometimes appearing purple or blue. If the reduction +flame is directed on this deposit, it is dissipated with a blue light. + +_Tellurium_ is deposited on the charcoal as a white sublimate, +sometimes changing at the margin to an orange or red color. The +oxidation flame drives the deposit over the charcoal, while the +reduction-flame dissipates it with a greenish color. + +_Arsenic_ is vaporized rapidly, while there is deposited around the +assay a white incrustation of arsenious acid. This deposit will extend +to some distance from the assay, and is readily volatilized, the +reducing flame producing the characteristic alliaceous color. + + * * * * * + +The following metals, or their compounds, are reduced when fused with +soda on charcoal, in the flame of reduction. They are reduced to +metallic particles, but give no incrustation, viz. nickel, cobalt, +iron, tin, copper, gold, silver, platinum, tungsten, and molybdenum. + +The particles of iron, nickel, and cobalt, it should be borne in mind, +are attracted by the magnet. + +The following substances are neither fused nor reduced in soda, viz. +alumina, magnesia, lime, baryta, strontia, the oxide of uranium, the +oxides of cerium, zirconia, tantalic acid, thorina, glucina, and +yttria. Neither are the alkalies, as they sink into the charcoal. The +carbonates of the earths, strontia, and baryta fuse. + + * * * * * + + + + +Part III + +SPECIAL REACTIONS; OR, THE BEHAVIOR OF SUBSTANCES BEFORE THE BLOWPIPE. + + +Analytical chemistry may be termed the art of converting the unknown +constituents of substances, by means of certain operations, into new +combinations which we recognize through the physical and chemical +properties which they manifest. + +It is, therefore, indispensably necessary, not only to be cognizant of +the peculiar conditions by which these operations can be effected, but +it is absolutely necessary to be acquainted with the forms and +combinations of the resulting product, and with every modification +which may be produced by altering the conditions of the analysis. + +We shall first give the behavior of simple substances before the +blowpipe; and the student should study this part thoroughly, by +repeating each reaction, so that he can acquire a knowledge of the +color, form, and physical properties in general, of the resulting +combination. There is nothing, perhaps, which will contribute more +readily to the progress of the pupil, than thorough practice with the +reactions recommended in this part of the work, for when once the +student shall have acquired a practical eye in the discernment of the +peculiar appearances of substances after they have undergone the +decompositions produced by the strong heat of the blowpipe flame, +together with the reactions incident to these changes, then he will +have greatly progressed in his study, and the rest will be +comparatively simple. + + +A. METALLIC OXIDES. + + +GROUP FIRST.--THE ALKALIES: POTASSA, SODA, AMMONIA, AND LITHIA. + +The alkalies, in their pure, or carbonated state, render reddened +litmus paper blue. This is likewise the case with the sulphides of the +alkalies. The neutral salts of the alkalies, formed with the strong +acids, do not change litmus paper, but the salts formed with the weak +acids, render the red litmus paper blue; for instance, the alkaline +salts with boracic acid. Fused with borax, soda, or microcosmic salt, +they give a clear bead. The alkalies and their salts melt at a low red +heat. The alkalies cannot be reduced to the metallic state before the +blowpipe. They are not volatile when red hot, except the alkali +ammonia, but they are volatile at a white heat. + +(_a._) _Potassa._(KO).--It is not found free, but in combination with +inorganic and organic acids, as well in the animal as in the vegetable +organism, as in the mineral kingdom. In the pure, or anhydrous state, +or as the carbonate, potassa absorbs moisture, and becomes fluid, or +is deliquescent, as it is termed. By exposing potassa, or its easily +fusible salts (except the phosphate or borate), upon platinum wire, to +the point of the blue flame, there is communicated to the external +flame a violet color, in consequence of a reduction and reoxidation. +This color, though characteristic of all the potassa compounds, is +scarcely visible with the phosphate or borate salts of that alkali. +The admixture of a very little soda (1/300th) destroys the color +imparted by the potassa, while the flame assumes a yellow color, +characteristic of the soda. The presence of lithia changes the violet +color of the potash into red. The silicates of potassa must exist in +pretty large proportion before they can be detected by the violet +color of the flame, and those minerals must melt easily at the edges. +The presence of a little soda in these instances conceals the reaction +in the potassa entirely. + +If alcohol is poured over potassa compounds which are powdered, and +then set on fire, the external flame appears violet-colored, +particularly when stirred with a glass rod, and when the alcohol is +really consumed. The presence of soda in lithia will, in this case +likewise, hide by their own characteristic color, that of the potassa. + +The salts of potassa are absorbed when fused upon charcoal. The +sulphur, bromine, chlorine, and iodine compounds of potassa give a +white, but easily volatile sublimate upon the charcoal, around the +place where the fused substance reposed. This white sublimate +manifests itself only when the substance is melted and absorbed within +the charcoal, and ceases to be visible as soon as it is submitted to +the reducing flame, while the external flame is colored violet; +sulphate of potassa, for instance, is reduced by the glowing charcoal +into the sulphide. This latter is somewhat volatile, but by passing +through the oxidation flame, it is again oxidized into the sulphate. +This, being less volatile, sublimes upon the charcoal, but by exposing +it again to the flame of reduction, it is reduced and carried off to +be again oxidized by its passage through the oxidation flame. + +Potassa and its compounds give, with soda, borax or microcosmic salt, +as well when hot as cold, colorless beads, unless the acid associated +with the alkali should itself produce a color. When borax is fused +with some pure boracic acid, and sufficient of the oxide of nickel is +added, so that the beads appear of a brown color after being cooled, +and then the bead thus produced fused with the substance suspected to +contain potassa, in the oxidation flame, the brown color is changed to +blue. The presence of the other alkalies does not prevent this +reaction. As it is not possible to detect potassa compounds with +unerring certainty by the blowpipe flame, the the wet method should +be resorted to for the purpose of confirming it. + +The _silicates of potassa_ must be prepared as follows, for analytical +purposes by the wet way. Mix one part of the finely powdered substance +with two parts of soda (free from potassa), and one part of borax. +Fuse the mixture upon charcoal in the oxidation flame to a clear, +transparent bead. This is to be exposed again with the pincers to the +oxidation flame, to burn off the adhering coal particles. Then +pulverize and dissolve in hydrochloric acid to separate the silica; +evaporate to dryness, dissolve the residue in water, with the +admixture of a little alcohol, and test the filtrate with chloride of +platinum for potassa. + +(_b._) _Soda_ (NaO).--This is one of the most abundant substances, +although seldom found free, but combined with chlorine or some other +less abundant compound. Soda, its hydrate and salts manifest in +general the same properties as their respective potash compounds; but +the salts of soda mostly contain crystal water, which leaves the salts +if they are exposed to the air, and the salts effervesce. + +By exposing soda or its compounds upon a platinum wire to the blue +flame, a reddish-yellow color is communicated to the external flame, +which appears as a long brilliant stream and considerably increased in +volume. The presence of potash does not prevent this reaction of soda. +If there is too large a quantity of potash, the flame near to the +substance is violet-colored, but the edge of the flame exhibits the +characteristic tint of the soda. The presence of lithia changes the +yellow color to a shade of red. + +When alcohol is poured over powdered soda compounds and lighted, the +flame exhibits a reddish-yellow color, particularly if the alcohol is +stirred up with a glass rod, or if the alcohol is nearly consumed. + +Fused upon charcoal, soda compounds are absorbed by the coal. The +sulphide, chloride, iodide, and bromide of soda yield a white +sublimate around the spot where the substance is laid, but this +sublimate is not so copious as that of the potash compounds, and +disappears when touched with the reduction flame, communicating a +yellow color to the external flame. The presence of soda in compounds +must likewise be confined by reactions in the wet way. + +(_c._) _Ammonia_ (NH^{4}O).--In the fused state, and at the usual +temperature, ammonia is a pungent gas, and exerts a reaction upon +litmus paper similar to potash and soda. Ammonium is considered by +chemists as a metal, from the nature of its behavior with other +substances. It has not been isolated, but its existence is now +generally conceded by all chemists. The ammonia salts are volatile, +and many of them sublimate without being decomposed. + +The salts of ammonia, on being heated in the point of the blue flame, +produce a feeble green color in the external flame, just previous to +their being converted into vapor. But this color is scarcely visible, +and presents nothing characteristic. When the ammonia salts are mixed +with the carbonate of soda, and heated in a glass tube closed at one +end, carbonate of ammonia is sublimed, which can be readily recognized +by its penetrating smell of spirits of hartshorn. + +This sublimate will render blue a slip of red litmus paper. This can +be easily done by moistening the litmus paper, and then inserting the +end of it in the tube. By holding a glass rod, moistened with dilute +hydrochloric acid, over the mouth of the tube, a white vapor is +instantly rendered visible (sal ammoniac). + +(_d._) _Lithia_ (LiO).--In the pure state, lithia is white and +crystalline, not easily soluble in water, and does not absorb +moisture. It changes red litmus to blue, and at a low red heat it +melts. Lithia or its salts, exposed to the point of the blue flame, +communicates a red color to the external or oxidation flame, in +consequence of a reduction, sublimation, and re-oxidation of the +lithia. An admixture of potash communicates to this flame a +reddish-violet color, and the presence of soda that of a yellowish-red +or orange. If the soda, however, is in too great proportion, then its +intense yellow hides the red of the lithia. In the latter case the +substance under test must be only imperfectly fused in the oxidation +flame, and then dipped in wax or tallow. By exposing it now to the +reduction flame, the red color imparted to the external flame by the +lithia becomes visible, even if a considerable quantity of soda be +present. A particular phenomenon appears with the phosphate of lithia, +viz., the phosphoric acid itself possesses the property of +communicating to the flame a bluish-green color. By its combination +with lithia it still exhibits its characteristic color, while the +latter presents likewise its peculiar tint. Then we perceive a green +flame in the centre of the flame, while the red color of lithia +surrounds it. + +The _silicates_, which contain only a little lithia, produce only a +slight hue in the flame, and often none at all. We have to mix one +part of the silicate with two parts of a mixture composed of one part +of fluorspar and one and a half parts of bisulphate of potassa. +Moisten the mass with water so that the mass will adhere, and then +melt it upon a platinum wire in the reduction flame, when that of +oxidation will present the red color of lithia. + +The _Borates of lithia_ produce at first a green color, but it soon +yields to the red of lithia. When alcohol is poured over lithia or its +compounds, and inflamed, it burns with a deep red color, particularly +if the fluid is stirred up with a glass rod, or when the alcohol is +nearly consumed. This color presents the same modifications as the +corresponding ones communicated to the blowpipe as mentioned above. + +The salts of lithia are absorbed by charcoal when fused upon it. The +sulphide, bromide, iodide, and chloride of lithia produce upon the +charcoal a greyish-white sublimate, although not so copiously as the +corresponding compounds of potash and soda. This sublimate disappears +when touched by the reduction flame, while the oxidation flame gives +the characteristic color of lithia. + + +SECOND GROUP.--THE ALKALINE EARTHS, BARYTA, STRONTIA, LIME, AND +MAGNESIA. + +In the pure state, the alkaline earths are caustic, cause red litmus +paper to become blue, and are more or less soluble in water. Their +sulphides are also soluble. The carbonates and phosphates of the +alkaline earths are insoluble in water. By igniting the carbonates, +their carbonic acid is expelled, and the alkaline earths are left in +the caustic state. The alkaline earths are not volatile, and their +organic salts are converted, by ignition, into carbonates. + +(_a._) _Baryta._ (BaO).--This alkaline earth does not occur free in +nature, but combined with acids, particularly with carbonic and +sulphuric acids. In the pure state, baryta is of a greyish-white +color, presents an earthy appearance, and is easily powdered. When +sparingly moistened with water, it slakes, becomes heated, and forms a +dry, white powder. With still more water it forms a crystalline mass, +the hydrate of baryta, which is completely soluble in hot water. Pure +baryta is infusible; the hydrate fuses at a red heat, without the loss +of its hydratic water; if caustic baryta is exposed for too great a +length of time to the flame, it absorbs water, originated by the +combustion, and becomes a hydrate, when it will melt. Salts of baryta, +formed with most acids, are insoluble in water; for instance, the +salts with sulphuric, carbonic, arsenic, phosphoric, and boracic +acids. The salts of baryta, soluble in water, are decomposed by +ignition, except the chloride. + +Carbonate of baryta loses its carbonic acid at a red heat, becomes +caustic, and colors red litmus paper blue. + +By exposing baryta or its compounds upon a platinum wire, or a +splinter of the substance held with the platinum tongs, to the point +of the blue flame, a pale apple-green color is communicated to the +external flame. This color appears at first very pale, but soon +becomes more intense. This color is most visible if the substance is +operated with in small quantities. The chloride of barium produces the +deepest color. This color is less intense if the carbonate or sulphate +is used. The presence of strontia, lime, or magnesia, does not +suppress the reaction of the baryta, unless they greatly predominate. + +When alcohol is poured over baryta or its salts, and inflamed, a +feeble green color is communicated to the flame, but this color should +not be considered a characteristic of the salt. + +Baryta and its compounds give, when fused with carbonate of soda upon +platinum foil, a clear bead. Fused with soda upon charcoal, it is +absorbed. The sulphate fuses at first to a clear bead, which soon +spreads, and is absorbed and converted while boiling into a hepatic +mass. If this mass is taken out, placed upon a piece of polished +silver and moistened with a little water, a black spot of sulphide of +silver is left after washing off the mass with water. + +Borax dissolves baryta and its compounds with a hissing noise, as well +in the flame of oxidation as in that of reduction. There is formed a +clear bead which, with a certain degree of saturation, is clear when +cold, but appears milk-white when overcharged, and of an opal, enamel +appearance, when heated intermittingly, or with a vacillating flame, +that changes frequently from the oxidating to the reducing flame. +Baryta and its compounds produce the same reactions with microcosmic +salt. + +Baryta and its compounds fuse when exposed to ignition in the +oxidizing flame. Moistened with the solution of nitrate of cobalt, and +heated in the oxidation flame, it presents a bead, colored from +brick-red to brown, according to the quantity used. This color +disappears when cold, and the bead falls to a pale grey powder after +being exposed awhile to the air. When heated again, the color does not +appear until fusion is effected. If carbonate of soda is fused upon +platinum wire with so much of the sesquioxide of manganese that a +green bead is produced, this bead, when fused with a sufficient +quantity of baryta, or its compounds, after cooling, will appear of a +bluish-green, or light blue color. + +(_b._) _Strontia_ (SrO).--Strontia and its compounds are analogous to +the respective ones of baryta. The hydrate of strontia has the same +properties as the hydrate of baryta, except that it is less soluble in +water. The carbonate of strontia fuses a little at a red heat, swells, +and bubbles up like cauliflower. This produces, in the blowpipe flame, +an intense and splendid light, and now produces an alkaline reaction +upon red litmus paper. The sulphate of strontia melts in the oxidation +flame upon platinum foil, or upon charcoal, to a milk-white globule. +This fuses upon charcoal, spreads and is reduced to the sulphide, +which is absorbed by the charcoal. It now produces the same reactions +upon polished silver as the sulphate of baryta under the same +conditions. By exposing strontia and its compounds upon platinum wire, +or as a splinter with the platinum tongs, to the point of the blue +flame, the external flame appears of an intense crimson color. The +deepest red color is produced by the chloride of strontium, +particularly at the first moment of applying the heat. After the salt +is fused, the red color ceases to be visible in the flame, by which it +is distinguished from the chloride of lithium. The carbonate of +strontia swells up and produces a splendid white light, while the +external flame is colored of a fine purple-red. The color produced by +the sulphate of strontia is less intense. The presence of baryta +destroys the reaction of the strontia, the flame presenting the light +green color of the baryta. + +If alcohol is poured over powdered strontia and inflamed, the flame +appears purple or deep crimson, particularly if the fluid is stirred +with a glass rod, and when the alcohol is nearly consumed. + +The insoluble salts of strontia do not produce a very intense color. +Baryta does not prevent the reaction of the soluble salts of strontia, +unless it exists greatly in excess. In the presence of baryta, +strontia can be detected by the following process: mix some of the +substance under examination with some pure graphite and water, by +grinding in an agate mortar. Place the mixture upon charcoal, and +expose it for a while to the reduction flame. The substance becomes +reduced to sulphide of barium and sulphide of strontium, when it +should be dissolved in hydrochloric acid. The solution should be +evaporated to dryness, redissolved in a little water, and enough +alcohol added that a spirit of 80 per cent. is produced. Inflame the +spirit, and if strontia is present, the flame is tinged of a red +color. This color can be discerned more distinctly by moistening some +cotton with this spirit and inflaming it. + +If strontia or its compounds are fused with a green bead of carbonate +of soda and sesquioxide of manganese, as described under the head of +baryta, a bead of a brown, brownish-green, or dark grey color is +produced. Carbonate of soda does not dissolve pure strontia. The +carbonate and sulphate of strontia melt with soda upon platinum foil +to a bead, which is milk-white when cold, but fused upon charcoal they +are absorbed. Strontia or its compounds produce with borax, or +microcosmic salt, the same reactions as baryta. When they are +moistened with nitrate of cobalt, and ignited in the oxidizing flame, +a black, or grey infusible mass is produced. + +(_c._) _Lime, Oxide of Calcium _(CaO).--Lime does not occur free in +nature, but in combination with acids, chiefly the carbonic and +sulphuric. The phosphate occurs principally in bones. The hydrate and +the salts of lime are in their properties similar to those of the two +preceding alkaline earths. In the pure state, the oxide of calcium is +white; it slakes, produces a high temperature, and falls into a white +powder when sprinkled with a little water. It is now a hydrate, and +has greatly increased in volume. The hydrate of lime is far less +soluble in water than either those of baryta or strontia, and is less +soluble in hot water than in cold. Lime, its hydrate and sulphide of +calcium, have a strong alkaline reaction upon red litmus paper. Lime +and its hydrate are infusible, but produce at a strong red heat a very +intense and splendid white light, while the hydrate loses its water. +The carbonate of lime is also infusible, but at a red heat the +carbonic acid is expelled, and the residue becomes caustic, appears +whiter, and produces an intenser light. The sulphate of lime melts +with difficulty, and presents the appearance of an enamelled mass when +cold. By heating it upon charcoal it fuses in the reducing flame, and +is reduced to a sulphide. This has a strong hepatic odor, and exerts +an alkaline reaction upon red litmus paper. By exposing lime, or its +compounds, upon platinum wire--or as a small splinter of the mineral +in the platinum tongs--to the point of the blue flame, a purple color, +similar to that of lithia and strontia, is communicated to the +external flame, but this color is not so intense as that produced by +strontia, and appears mixed with a slight tinge of yellow. This color +is most intense with the chloride of calcium, while the carbonate of +lime produces at first a yellowish color, which becomes red, after the +expulsion of the carbonic acid. Sulphate of lime produces the same +color, but not so intense. Among the silicates of lime only the +tablespar (3CaO, 2SiO^{3}) produces a red color. Fluorspar (CaFl) +produces a red as intense as pure lime, and fuses into a bead. +Phosphate and borate of lime produce a green flame which is only +characteristic of their acids. The presence of baryta communicates a +green color to the flame. The presence of soda produces only a yellow +color in the external flame. + +If alcohol is poured over lime or its compounds and inflamed, a red +color is communicated to the flame. The presence of baryta or soda +prevents this reaction. Lime and its compounds do not dissolve much by +fusion with carbonate of soda. If this fusion is effected on charcoal, +the carbonate of soda is absorbed and the lime remains as a +half-globular infusible mass on the charcoal. This is what +distinguishes lime from baryta and strontia, and is a good method of +separating the former from the latter. Lime and its compounds fuse +with borax in the oxidizing and reducing flames to a clear bead, which +remains clear when cold, but when overcharged with an excess or heated +intermittingly, the bead appears, when cold, crystalline and uneven, +and is not so milk-white as the bead of baryta or strontia, produced +under the same circumstances. The carbonate of lime is dissolved with +a peculiar hissing noise. Microcosmic salt dissolves a large quantity +of lime into a clear bead, which is milky when cold. When the bead has +been overcharged with lime, by a less excess, or by an intermittent +flame, we will perceive in the bead, when cold, fine crystals in the +form of needles. Lime and its compounds form by ignition with nitrate +of cobalt, a black or greyish-black infusible mass. + +(_d._) _Magnesia_ (MgO).--Magnesia occurs in nature in several +minerals. It exists in considerable quantity combined with carbonic, +sulphuric, phosphoric, and silicic acids, etc. Magnesia and its +hydrate are white and very voluminous, scarcely soluble in hot or cold +water, and restores moistened red litmus paper to its original blue +color. Magnesia and its hydrate are infusible, the latter losing its +water by ignition. The carbonate of magnesia is infusible, loses its +carbonic acid at a red heat, and shrinks a little. It now exerts upon +red litmus paper an alkaline reaction. The sulphate of magnesia, at a +red heat, loses its water and sulphuric acid, is entirely infusible, +and gives now an alkaline reaction. The artificial Astrachanit (NaO, +SO^{3} + MgO, SO^{3} + 4HO) fuses easily. When fused on charcoal, the +greater part of the sulphate of soda is absorbed, and there remains an +infusible mass. + +Magnesia and its compounds do not produce any color in the external +flame, when heated in the point of the blue flame. The most of the +magnesia minerals yield some water when heated in a glass tube closed +at one end. + +Magnesia, in the pure state, or as the hydrate, does not fuse with +soda. Some of its compounds are infusible likewise with soda, and +swell up slightly, while others of them melt with soda to a slightly +opaque mass. Some few (such as the borate of magnesia) give a clear +bead with soda, though it becomes slightly turbid by cooling when +saturated with magnesia, and crystallizes in large facets. + +Magnesia and its compounds give beads with borax and microcosmic salt +similar to those of lime. By igniting magnesia or its compounds very +strongly in the oxidizing flame, moistening with nitrate of cobalt, +and re-igniting in the oxidation flame, they present, after a +continued blowing, a pale flesh-color, which is more visible when +cold. It is indispensable that the magnesia compounds should be +completely white and free of colored substances, or the color referred +to cannot be discerned. In general the reactions of magnesia before +the blowpipe are not sufficient, and it will be necessary to confirm +its presence or absence by aid of reagents applied in the wet way. + + +THIRD GROUP.--THE EARTHS, ALUMINA, GLUCINA, YTTRIA, THORINA, AND +ZIRCONIA. + +The substances of this group are distinguished from the preceding by +their insolubility in water, in their pure or hydrated state--that +they have no alkaline reaction upon litmus paper, nor form salts with +carbonic acid. The earths are not volatile, and, in the pure state, +are infusible. They cannot be reduced to the metallic state before the +blowpipe. The organic salts are destroyed by ignition, while the +earths are left in the pure state, mixed with charcoal, from the +organic acids. The most of their neutral salts are insoluble in water; +the soluble neutral salts change blue litmus paper to red, and lose +their acids when ignited. + +(_a._) _Alumina_ (Al^{2}O^{3}).--This earth is one of our most common +minerals. It occurs free in nature in many minerals, as sapphire, +etc.; or in combination with sulphuric acid, phosphoric acid, and +fluorine, and chiefly silicates. Pure alumina is a white crystalline +powder, or yellowish-white, and amorphous when produced by drying the +hydrate, separated chemically from its salts. Alumina is quite +unalterable in the fire; the hydrate, however, losing its water at a +low red heat. The neutral salts of alumina, with most acids, are +insoluble in water. Those soluble in it have an acid reaction upon +litmus paper, changing the blue into red. + +The sulphates of alumina eliminate water when heated in a glass tube +closed at one end. By ignition, sulphurous acid (SO^{2}) is given off, +which can be recognized by its smell, and by its acid reaction upon +blue litmus paper, when a small strip of it moistened is brought +within the orifice of the tube; an infusible residue is left in the +tube. + +The greater part of the alumina compounds give off water with heat; +the most of them are also infusible, except a few phosphates and +silicates. + +Pure alumina does not fuse with carbonate of soda. The sulphates, when +exposed upon charcoal with soda to the reducing flame, leave a hepatic +residue. The phosphates melt with a little soda, with a hissing noise, +to a semi-transparent mass, but they are infusible with the addition +of soda, and give only a tough mass. This is the case, likewise, with +the silicates of alumina. Fluoride of aluminium melts with carbonate +of soda to a clear bead, spreads by cooling, and appears then +milk-white. Borax dissolves the alumina compounds slowly in the +oxidizing and reducing flames to a clear bead, which is also clear +when cold, or heated intermittingly with a vacillating flame. The bead +is turbid, as well in the heat as the cold, when an excess of alumina +is present. When the alumina compound is added to excess in the +powdered form, the bead appears crystalline upon cooling, and melts +again with great difficulty. + +Alumina and its compounds are slowly dissolved in the microcosmic salt +to a bead, clear in both flames, and when hot or cold. When alumina is +added to excess, the undissolved portion appears semi-transparent. +Alumina melts with bisulphate of potash into a mass soluble in water. +When the powdered alumina compounds are strongly ignited in the +oxidizing flame, then moistened with nitrate of cobalt, and re-ignited +in the oxidizing flame, an infusible mass is left, which appears, when +cooled, of an intense blue color. The presence of colored metallic +oxides, in considerable quantity, will alter or suppress this +reaction. The silicates of the alkalies produce, in a very strong +heat, or continued heat, with nitrate of cobalt, a pale blue color. +The blue color produced by alumina is only distinctly visible by +daylight; by candle-light it appears of a dirty violet color. + +(_b._) _Glucina._ (G^{2}O^{3}).--Glucina only occurs in a few rare +minerals, in combination with silica and alumina. It is white and +insoluble in the pure state, and its properties generally are similar +to those of alumina. The most of its compounds are infusible, and +yield water by distillation. Carbonate of soda does not dissolve +glucina by ignition. Silicate of glucina melts with carbonate of soda +to a colorless globule. Borax and microcosmic salt dissolve glucina +and its compounds to a colorless bead which, when overcharged with +glucina, or heated with the intermittent flame appears, after cooling, +turbid or milk-white. Glucina yields, by ignition with nitrate of +cobalt, a black, or dark grey infusible mass. + +(_c._) _Yttria_ (YO) occurs only in a few rare minerals, and usually +in company with terbium and erbium. Its reactions before the blowpipe +are similar to the preceding, but for its detection in compounds it +will be necessary to resort to analysis in the wet way. + +(_d._) _Zirconia_ (Zr^{2}O^{3}).--This substance resembles alumina in +appearance, though it occurs only in a few rare minerals. It is in the +pure state infusible, and at a red heat produces such a splendid and +vivid white light that the eyes can scarcely endure it. Its other +reactions before the blowpipe are analogous to glucina. Microcosmic +salt does not dissolve so much zirconia as glucina, and is more prone +to give a turbid bead. Zirconia yields with nitrate of cobalt, when +ignited, an infusible black mass. To recognize zirconia in compounds +we must resort to fluid analysis. + +(_e._) _Thorina_ (ThO).--This is the rarest among the rare minerals. +In the pure state it is white and infusible, and will not melt with +the carbonate of soda. Borax dissolves thorina slowly to a colorless, +transparent bead, which will remain so when heated with the +intermittent flame. If overcharged with the thorina, the bead +presents, on cooling, a milky hue. Microcosmic salt dissolves the +thorina very tardily. By ignition with nitrate of cobalt, thorina is +converted into an infusible black mass, + + +CLASS II. + + +FOURTH GROUP. CERIUM, LANTHANIUM, DIDYMIUM, COLUMBIUM, NIOBIUM, +PELOPIUM, TITANIUM, URANIUM, VANADIUM, CHROMIUM, MANGANESE. + +The substances of this group cannot be reduced to the metallic state, +neither by heating them _per se_, nor by fusing them with reagents. +They give by fusion with borax or microcosmic salt, colored beads, +while the preceding groups give colorless beads. + +(_a._) _Cerium_ (Ce).--This metal occurs in the oxidated state in a +few rare minerals, and is associated with lanthanium and didymium, +combined with fluorine, phosphoric acid, carbonic acid, silica, etc. +When reduced artificially, it forms a grey metallic powder. + +(_a._) _Protoxide of Cerium_ (CeO).--It exists in the pure state as +the hydrate, and is of a white color. It soon oxidizes and becomes +yellow, when placed in contact with the air. When heated in the +oxidation flame, it is converted into the sesquioxide, and then is +changed into light brick-red color. In the oxidation flame it is +dissolved by borax into a clear bead, which appears of an orange or +red while hot, but becomes yellow upon cooling. When highly saturated +with the metal, or when heated with a fluctuating flame, the bead +appears enamelled as when cold. In the reduction flame it is dissolved +by borax to a clear yellow bead, which is colorless when cold. If too +much of the metal exists in the bead, it then appears enamelled when +cooled. + +Microcosmic salt dissolves it, in the oxidation flame, to a clear +bead, which is colored dark yellow or orange, but loses its color when +cold. In the reduction flame the bead is colorless when either hot or +cold. Even if highly saturated with the metal, the bead remains +colorless when cold. By fusing it with carbonate of soda upon charcoal +in the reduction flame, the soda is absorbed by the charcoal, while +the protoxide of the metal remains as a light grey powder. + +(_B._) _Sesquioxide of Cerium_ (Ce^{2}O^{3}).--This oxide, in the pure +state, is a red powder. When heated with hydrochloric acid, it +produces chlorine gas, and is dissolved to a salt of the protoxide. It +is not affected by either the flame of oxidation or of reduction; when +fused with borax or microcosmic salt, it acts like the protoxide. It +does not fuse with soda upon charcoal. In the reduction flame it is +reduced to the protoxide, which remains of a light grey color, while +the soda is absorbed by the charcoal. + +(_b._) _Lanthanium_ (La.)--This metal is invariably associated with +cerium. It presents, in its metallic state, a dark grey powder, which +by compression acquires the metallic lustre. + +The _oxide of lanthanium_ (LaO) is white, and its salts are colorless. +Heated upon charcoal, it does not change either in the oxidation flame +or that of reduction. With borax, in the flame of oxidation or +reduction, it gives a clear colorless bead. This bead, if saturated, +and when hot, presents a yellow appearance, but is clouded or +enamelled when cold. With microcosmic salt the same appearance is +indicated. It does not fuse with carbonate of soda, but the soda is +absorbed by the charcoal, while the oxide remains of a grey color. + +(_c._) _Didymium_ (D).--This metal occurs only in combination with the +preceding ones, and it is therefore, like them, a rare one. + +_Oxide of Didymium_ (DO).--This oxide is of a brown color, while its +salts present a reddish-violet or amethyst color. The oxide is +infusible in the oxidation flame, and in that of reduction it loses +its brown color and changes to grey. With borax in the oxidation +flame, it fuses to a clear dark red or violet bead, which retains its +clearness when highly saturated with the oxide, or if heated with a +fluctuating flame. + +The reactions with microcosmic salt are the same as with borax. + +It does not melt with carbonate of soda upon charcoal, but the oxide +remains with a grey color, while the soda is absorbed by the charcoal. + +(_d._) _Columbium,_ (_Tantalum_--Ta).--This rare metal occurs quite +sparingly in the minerals _tantalite_, _yttrotantalite_, etc., as +columbic acid. In the metallic state, it presents the appearance of a +black powder, which, when compressed, exhibits the metallic lustre. +When heated in the air it is oxidized into columbic acid, and is only +soluble in hydrofluoric acid, yielding hydrogen. It is oxidized by +fusion with carbonate of soda or potash. + +_Columbic Acid_ (Ta^{2}O^{3}) is a white powder, and is infusible. +When heated in the flame of oxidation or reduction, it appears of a +light yellow while hot, but becomes colorless when cold. With borax, +in the flames of oxidation and reduction, it fuses to a clear bead, +which appears by a certain degree of saturation, of a yellow color so +long as it continues hot, but becomes colorless when cold. If +overcharged, or heated with an intermittent flame, it presents an +enamel white when cool. + +It melts with microcosmic salt quite readily in both of the flames, to +a clear bead, which appears, if a considerable quantity of columbic +acid be present, of a yellow color while hot, but colorless when cold, +and does not become clouded if the intermittent flame be applied to +it. + +With carbonate of soda it fuses with effervescence to a bead which +spreads over the charcoal. Melted with more soda, it becomes absorbed +by the charcoal. + +It yields, moistened with a solution of nitrate of cobalt, and exposed +to the oxidation flame after continued blowing, an infusible mass, +presenting while hot a light grey color, but after being cooled that +of a light red, similar to the color presented by magnesia under the +same circumstances. But if there be some alkali mixed with it, a +fusion at the edges will be manifest, and it will yield by cooling a +bluish-black mass. + +(_e._) _Niobium_ (Ni).--This metal occurs as niobic acid in columbite +(tantalite). Niobic acid is in its properties similar to columbic +acid. It is white and infusible. By heating it either in the flames of +reduction or oxidation, it presents as long as it continues hot, a +greenish-yellow color, but becomes white when cool. Borax dissolves it +in the oxidation flame quite readily to a clear bead, which, with a +considerable quantity of niobic acid, is yellow when hot, but +transparent and colorless when cold. A saturated bead is clear when +either hot or cold, but becomes opaque when heated intermittingly. + +In the flame of reduction, borax is capable of dissolving more of the +niobic acid, so that a bead overcharged and opaque in the oxidation +flame appears quite clear when heated in the flame of reduction. A +bead overcharged in the flame of reduction, appears by cooling dim and +bluish-grey. + +Microcosmic salt dissolves in the flame of oxidation a great quantity +of it to a clear bead, which is yellow while hot, but colorless when +cold. + +In the flame of reduction, and in presence of a considerable quantity +of niobic acid, the bead appears while hot of a light dirty blue +color, and when cold, of a violet hue; but by the addition of more +niobic acid, the bead, when hot, is of a dirty dark blue color, and +when cold, of a transparent blue. In the presence of the oxides of +iron, the bead is, while hot, of a brownish-red color, but changing +when cool to a dark yellow. + +This acid fuses with an equal quantity of carbonate of soda upon +charcoal, to a bead which spreads very quickly, and is then infusible. +When fused with still more soda, it is absorbed. + +When moistened with nitrate of cobalt, and heated in the flame of +oxidation, it yields an infusible mass which appears grey when hot, +and dirty green when cold; but if the heat has been too strong, it is +fused a little at the edges, which present a dark bluish-grey color. + +_Pelopium_ (Pe).--This metal occurs as an acid in the mineral +columbite (tantalite), and is very similar to the two preceding +metals. + +(_f._) _Pelopic Acid_ (PeO^{3}).--This acid is white, and appears +yellow when heated, but resumes its white color when cold. Borax +dissolves it in the oxidation flame to a clear colorless bead, which +appears, when overcharged and heated intermittingly, enamel-white when +cold. This is likewise the case in the flame of reduction, but when +overcharged the color is light grey, when the bead is cooled. + +Microcosmic salt dissolves it in the flame of oxidation, to a clear +yellow bead, which loses its color when cold. In the reduction flame, +when the bead is highly saturated, a violet-brown color is produced. +In presence of the oxides of iron, the reactions are like those of +niobic acid. With carbonate of soda, the reactions are similar to +those of niobic acid. By heating with nitrate of cobalt, it yields a +light grey infusible mass. + +(_g._) _Titanium_ (Ti).--This metal occurs occasionally in the slags +of iron works, in the metallic state, as small cubical crystals of a +red color. It is a very hard metal, and very infusible. Titanic acid +occurs in nature crystallized in _anatase_, _arkansite_, _brookite_, +and _rutile_. Titanium is harder than agate, entirely infusible, and +loses only a little of its lustre, which can be regained by fusion +with borax. It does not melt with carbonate of soda, borax, or +microcosmic salt, and is insoluble in every acid except the +hydrofluoric. By ignition with saltpetre it is converted into titanic +acid, which combines with the potassium, forming the titanate of +potassium. + +_Titanic Acid_ (TiO^{2}) is white, insoluble, and, when heated, it +appears yellow while hot, but resumes upon cooling its white color. + +Borax dissolves it in the oxidation flame to a clear yellow bead, +which when cool is colorless. When overcharged, or heated with the +intermitting flame, it is enamel-white after being cooled. In the +reduction flame, the bead appears yellow, if the acid exists in small +quantity, but if more be added, then it is of an orange, or dark +yellow, or even brown. The saturated bead, when heated intermittingly, +appears when cold of an enamelled blue. By addition of the acid, and +by heating the bead on charcoal in the reduction flame, it becomes +dark yellow while hot, but dark blue, or black and opaque when cold. +This bead appears, when heated intermittingly, of a light blue, and +when cold, enamelled. + +Microcosmic salt fuses with it in the oxidation flame to a clear +colorless bead, which appears yellow only in the presence of a +quantity of titanic acid, though by cooling it loses its color. In the +reduction flame this bead exhibits a yellow color when hot, but is red +while cooling, and when cold of a beautiful bluish-violet. If the bead +is overcharged, the color becomes so dark that the bead appears +opaque, though not presenting an enamel appearance. By heating the +bead again in the oxidation flame the color disappears. The addition +of some tin promotes the reduction. If the titanic acid contains oxide +of iron, or if some is added, the bead appears, when cold, +brownish-yellow, or brownish-red. + +By fusion with carbonate of soda, titanic acid is dissolved with +effervescence to a clear dark yellow bead, which crystallizes by +cooling, whereby so much heat is eliminated, that the bead, at the +instant of its crystallization, glows with great brightness. A +reduction to a metal cannot, however, be effected. By ignition with a +solution of nitrate of cobalt in the oxidation flame, it yields an +infusible yellowish-green mass. + +(_h._) _Uranium_ (U).--This rare metal occurs in the form of protoxide +along with other oxides, in the mineral _pitch-blende_; as peroxide in +_uranite_ and _uran-mica_, associated with phosphoric acid and lime. + +In the metallic state it presents the appearance of a dark grey mass, +which is infusible, and remains unchanged when under water, or when +exposed to dry air, but, when heated in the oxidation flame, it +becomes oxidized, with lively sparkling, to a dark green mass, +composed of the protoxide and peroxide. + +The _protoxide of uranium_ (UO) is black, uncrystalline, or forms a +brown powder. When exposed to heat it is converted partially into +peroxide, when it has a dark green color. + +The _peroxide of uranium_ (U^{2}O^{3}) is of an orange color, while +its hydrate is of a fine yellow color, and in the form of a powder. +The salts are yellow. + +By heating it in the oxidation flame, it acquires a dark green color, +and is partly reduced to protoxide. In the reduction flame it presents +a black appearance, and is there completely reduced to protoxide. + +Borax dissolves it in the oxidation flame to a clear dark yellow bead, +which is colorless when cold, if the metal is not present in great +quantity. If more of the metal, or peroxide, be added, the bead +changes to orange when hot, and light yellow when cold. When heated +with the intermittent flame, it requires a large quantity of the +peroxide to produce an enamel appearance in the cooled bead. + +In the flame of reduction the bead becomes of a dirty green color, +being partly reduced to protoxide, and appears, with a certain degree +of saturation, black, when heated intermittingly, but never enamelled. +The bead appears on charcoal, and with the addition of tin, of a dark +green color. + +It fuses with microcosmic salt in the oxidation flame to a clear +yellow bead, which is greenish-yellow when cold. In the reduction +flame it produces a beautiful green bead, which increases when cold. + +When fused upon charcoal with the addition of tin, its color is +darker. Carbonate of soda does not dissolve it, although with a very +small portion of soda it gives indications of fusion, but with still +more of the soda it forms a yellow, or light-brown mass, which is +absorbed by the charcoal, but it is not reduced to the metallic state. + +(_i._) _Vanadium_ (V).--This very rare mineral is found in small +quantity in iron-ores, in Sweden, and as vanadic acid in a few rare +minerals. The metal presents the appearance of an iron-grey powder, +and sometimes that of a silver-white mass. It is not oxidized either +by air or water, and is infusible. + +_Vanadic Acid_ (VO^{3}) fuses upon platinum foil to a deep orange +liquid, which becomes crystalline after cooling. When fused upon +charcoal, one part of it is absorbed, while the rest remains upon the +charcoal and is reduced to protoxide similar in appearance to +graphite. + +A small portion of it fuses with borax in the oxidation flame to a +clear colorless bead, which appears, with the addition of more vanadic +acid, of a yellow color, but changes to green when cold. + +In the reduction flame the bead is brown while hot, but changes, upon +cooling, to a beautiful sapphire-green. At the moment of +crystallization, and at a degree of heat by which at daylight no +glowing of the heated mass is visible it begins to glow again. The +glow spreads from the periphery to the centre of the mass, and is +caused by the heat liberated by the sudden crystallization of the +mass. It now exhibits an orange color, and is composed of needle +crystals in a compact mass. + +Microcosmic salt and vanadic acid fuse in the oxidation flame to a +dark yellow bead which, upon cooling, loses much of its color. + +In the reduction flame the bead is brown while hot, but, upon cooling, +acquires a beautiful green color. + +Vanadic acid fuses with carbonate of soda upon charcoal, and is +absorbed. + +(_k._) _Chromium_ (Cr) occurs in the metallic state only in a very +small quantity in meteoric iron, but is frequently found in union with +oxygen, as oxide in chrome iron ore, and as chromic acid in some lead +ores. + +In the metallic state it is of a light grey color, with but little +metallic lustre, very hard, and not very fusible. Acids do not act +upon it, except the hydrofluoric; fused with nitre, it forms chromate +of potassa. It is unaltered in the blowpipe flame. + +_Sesquioxide of Chromium_ (Cr^{2}O^{3}).--This oxide forms black +crystals of great hardness, and is sometimes seen as a green powder. +Its hydrate (Cr^{2}O^{3} + 6HO) is of a bluish-grey color. It forms +with acids two classes of isomeric salts, some of which are of a +green color, and the others violet-red or amethyst. The neutral and +soluble salts have an acid reaction upon blue litmus paper, and are +decomposed by ignition. + +Sesquioxide of chromium in the oxidation and reduction flames is +unchangable. When exposed to heat, the hydrate loses its water, and +gives a peculiarly beautiful flame. In the oxidation flame borax +dissolves the sesquioxide of chromium slowly to a yellow bead (chromic +acid) which is yellowish green when cold. Upon the addition of more of +the oxide, the bead is dark red while hot, but changes to green as it +becomes cold. + +In the reduction flame the bead is of a beautiful green color, both +while hot and when cold. It is here distinguished from vanadic acid, +which gives a brownish or yellow bead while hot. + +With microcosmic salt it fuses in the oxidation flame to a clear +yellow bead, which appears, as it cools, of a dirty-green, color, but +upon being cool is of a fine green color. If there be a superabundance +of the oxide, so that the microcosmic salt cannot dissolve it, the +bead swells up, and is converted into a foamy mass, in consequence of +the development of gases. + +In the reduction flame it fuses to a fine green bead. The addition of +a little tin renders the green still deeper. + +Sesquioxide of chromium fuses with carbonate of soda upon platinum +foil to a brown or yellow bead, which, upon cooling, appears of a +lighter color and transparent (chromate of sodium). + +When fused with soda upon charcoal, the soda is absorbed, and the +green oxide is left upon it, but is never reduced to the metallic +state. + +_Chromic Acid_ (CrO^{3}) crystallizes in the form of deep ruby red +needles. It is decomposed into sesquioxide and oxygen when heated. +This decomposition is attended with a very lively emission of light, +but this is not the case if the chromic acid has been attained by the +coöperation of an aqueous solution, unless the reduction is effected +in the vapor of ammonia. Before the blowpipe chromic acid produces the +same reactions as the sesquioxide. + +(_l._) _Manganese_ (Mn).--This metal occurs in considerable abundance, +principally as oxides, less frequently as salts, and sometimes in +combination with sulphur and arsenic. It is found in plants, and +passes with them into the animal body. In the metallic state, it is +found frequently in cast iron and steel. It is a hard, brittle metal, +fusible with difficulty, and of a light grey color. It tarnishes upon +exposure to the air and under water, and falls into a powder. + +_Protoxide of Manganese_ exists as a green powder; as hydrate +separated by caustic alkalies, it is white, but oxidizes very speedily +upon exposure to the air. The protoxide is the base of the salts of +manganese. These salts, which are soluble in water, are decomposed +when heated in the presence of the air--except the sulphate (MnO, +SO^{3}), but if the latter is exposed to ignition for awhile, it then +ceases to be soluble in water, or at least only sparingly so. + +_Sesquioxide of Manganese_ (Mn^{2}O^{3}) Occurs very sparingly in +nature as small black crystals (_Braunite_) which give, when ground, a +brown powder. When prepared by chemical process, it is in the form of +a black powder. The hydrate occurs sometimes in nature as black +crystals (_manganite_). By digestion with acids, it is dissolved into +salts of the protoxide. With hydrochloric acid, it yields chlorine. + +The _prot-sesquioxide of manganese_ (MnO + Mn^{2}O^{3}) occurs +sometimes in black _crystals_ (_hausmannite_). Prepared artificially, +it is in the form of a brown powder. + +_Peroxide of Manganese_ (MnO^{2}) occurs in considerable abundance as +a soft black amorphous mass, or crystallized as pyrolusite, also +reniform and fibrous. It is deprived of a part of its oxygen when +exposed to ignition. It eliminates a considerable quantity of chlorine +from hydrochloric acid, and is thereby converted into chloride of +manganese (ClMn). + +Most of the manganese compounds which occur in nature yield water when +heated in a glass tube closed at one end. The sesquioxide and peroxide +give out oxygen when strongly heated, which can be readily detected by +the increased glow which it causes, if a piece of lighted wood or +paper is brought to the mouth of the tube. The residue left in the +tube is a brown mass (MnO + Mn^{2}O^{3}). + +When exposed to ignition with free access of air, all manganese oxides +are converted into (MnO + Mn^{2}O^{3}), but without fusion. Such, at +least, is the statement of some of the German chemists, although it +will admit perhaps of further investigation. + +Manganese oxides fuse with borax in the oxidation flame to a clear and +intensely colored bead, of a violet hue while hot, but changing to red +as it cools. If a considerable quantity of the oxide is added, the +bead acquires a color so dark as to become opaque. If such be the +case, we have to press it flat, by which its proper color will become +manifest. + +In the reduction flame the bead is colorless. A very dark colored bead +must be fused upon charcoal with the addition of some tin. The bead +must be cooled very suddenly, for if it cools too slowly, it then has +time to oxidize again. This may be effected by pushing it off the +platinum wire, or the charcoal, and pressing it flat with the forceps. + +The oxides of manganese fuse with microcosmic salt in the oxidation +flame, to a clear brownish-violet bead, which appears reddish-violet +while cooling. This bead does not become opaque when overcharged with +manganese. As long as it is kept in fusion a continued boiling or +effervescence takes place, produced by the expulsion of oxygen, in +consequence of the fact that the microcosmic salt cannot dissolve much +sesquioxide, while the rest is reduced to protoxide, is re-oxidated, +and instantly again reduced. If the manganese is present in such a +minute quantity as not to perceptibly tinge the bead, the color may be +made to appear by the contact of a crystal of nitre while hot. The +bead foams up upon the addition of the nitre, and the foam appears, +after cooling, of a rose-red or violet color. In the reduction flame +the bead sometimes becomes colorless. + +The oxides of manganese fuse with carbonate of soda upon platinum +foil or wire, to a clear green bead, which appears bluish-green and +partially opaque when cold (manganate of soda NaO + MnO^{3}). A very +minute trace of manganese will produce this green color. The oxides of +manganese cannot be reduced upon charcoal with carbonate of soda +before the blowpipe. The soda is absorbed, and (MnO + Mn^{2}O^{3}) is +left. + + +GROUP FIFTH.--IRON, COBALT, NICKEL. + +The oxides of this group are reduced to the metallic state when fused +with carbonate of soda upon charcoal in the reduction flame. Metals +when thus reduced form powders, are not fusible or volatile in the +blowpipe flame, but they are attracted by the magnet. + +Furthermore, these oxides are not dissolved by carbonate of soda in +the oxidation flame, but they produce colored beads with borax and +microcosmic salt. + +(_a._) _Iron._--It occurs in great abundance in nature. It is found in +several places in America in the metallic state, and it likewise +occurs in the same state in meteors. It occurs chiefly as the oxide +(red hematite, brown hematite, magnetic oxide, etc.), and frequently +in combination with sulphur. Iron also forms a constituent of the +blood. + +Metallic iron is of a grey color, and presents the metallic lustre +vividly when polished. It is very ductile, malleable, and tenacious. +It is very hard at common temperatures, but soft and yielding at a red +heat. + +In dry and cold air, iron does not oxidize, but when the air is dry +and moist, it oxidizes rapidly. This likewise takes place with great +rapidity when the metal is heated to redness. When submitted to a +white heat iron burns with brilliant scintillations. + +_Protoxide of Iron_ (FeO).--This oxide does not occur pure in nature, +but in union with the peroxide of iron and other substances. It +presents the form of a black powder, and has some metallic lustre, is +brittle, and fuses at a high temperature to a vitreous looking mass. +It is attracted by the magnet, and of course is susceptible of +becoming magnetic itself. It forms with water a hydrate, but this +passes so rapidly into a state of higher oxidation, that it is +difficult to keep it in the pure state. + +_Magnetic Oxide of Iron_ (FeO + Fe^{2}O^{3}).--This peculiar oxide is +of a dark color, and is magnetic, so that tacks or small nails adhere +to it when brought in contact with it. It is the variety of the oxide +termed "loadstone." It is found frequently crystallized in octahedrons +in Scandinavia and other places. Magnetic oxide of iron is produced +when red-hot iron is hammered. + +_Sesquioxide of Iron_ (Fe^{2}O^{3}).--This oxide is found native in +great abundance as red hematite and specular iron, crystallized in the +rhombic form. In the crystalline state it is of a blackish-grey color, +and possessed of the metallic lustre. When powdered, it forms a +brownish-red mass. When artificially prepared, it presents the +appearance of a blood-red powder. It is not magnetic, and has less +affinity for acids than the protoxide. Its hydrate is found native as +brown hematite. + +By exposing the peroxide of iron to the oxidation flame, it is not +acted upon, but in the reduction flame it becomes reduced to the +magnetic oxide. + +The oxides of iron are dissolved by borax in the oxidation flame to a +clear dark-yellow or dark-red bead, which appears lighter while +cooling, and yellowish when cold. In the presence of a very small +quantity of iron, the bead appears colorless when cold. If the iron is +increased, the bead is opaque while cooling, and of a dirty +dark-yellow color when cold. In the reduction flame, and fused upon +platinum wire, the bead appears dark green (FeO + Fe^{2}O^{3}). By the +addition of some tin, and fused upon charcoal, the bead appears +bluish-green, or not unlike that of sulphate of iron. + +Microcosmic salt dissolves the oxides of iron in the oxidation flame +to a clear bead, which, by the addition of a considerable quantity of +iron, becomes of an orange color while hot, but gets lighter while +cooling, presenting finally a greenish hue, and gradually becoming +lighter, till, when cold, it is colorless. If the iron is increased, +the hot bead presents a dark red color, but while cooling a +brownish-red, which changes to a dirty-green, and, when cold, to a +brownish-red color. The decrease of the color during the transition +from the hot to the cold state is still greater in the bead formed by +the microcosmic salt. + +In the reduction flame no change is visible if the quantity of iron be +small. By the addition of more iron, the hot bead appears red, and +while cooling, changes to yellow, then green, and, when cold, is of a +dull red. By fusing the bead on charcoal with a small addition of tin, +it exhibits, while cooling, a bluish-green color, but, when cold, is +colorless. + +The oxides of iron are not dissolved in the oxidation flame by fusion +with carbonate of soda. By ignition with soda upon charcoal in the +reduction flame, they are absorbed and reduced to the metallic state. +Cut out this portion of the charcoal; grind it with the addition of +some water in an agate mortar, for the purpose of washing off the +carbon particles, when the iron will remain as a grey magnetic powder. + +(_b._) _Cobalt_ (Co) occurs in combination with arsenic and sulphur, +and associated with nickel and iron. It is found occasionally in +combination with selenium, and there are a traces of it in meteoric +iron. In the metallic state it is of a light, reddish-grey color, +rather brittle, and only fusible at a strong white heat; at common +temperatures it is unalterable by air or water. At a red heat, it +oxidizes slowly and decomposes water; at a white heat it burns with a +red flame. Cobalt is soluble in dilute sulphuric or hydrochloric acid +by the aid of heat, whereby hydrogen is eliminated. These solutions +have a fine red color. + +_Protoxide of Cobalt_ (CoO).--It is an olive-green powder, but, by +exposure to the air, it becomes gradually brown. Its hydrate is a rich +red powder. The solution of its salts is red, but the aqueous solution +is often blue. + +When heated in the oxidation flame, the protoxide is converted into +the black proto-sesquioxide (CoO + Co^{2}O^{3}). In the reduction +flame it shrinks and is reduced without fusion to the metallic state. +It is now attracted by the magnet and acquires lustre by compression. + +Borax dissolves it in the oxidation flame, and produces a clear, +intensely colored blue bead, which remains transparent and of the same +beautiful blue when cold. This blue is likewise manifest even if the +bead be heated intermittingly. If the cobalt exists in considerable +quantity, the color of the bead is so intense as to appear almost +black. + +This reaction of cobalt is so characteristic and sensitive that it can +detect a minute trace. + +With microcosmic salt the same reaction is exhibited, but not so +sensitive, nor is the bead so intensely colored when cold as that with +borax. + +By fusion with carbonate of soda upon a platinum wire, with a very +small portion of cobalt, a bright red colored mass is produced which +appears grey, or slightly green when cold. By fusion upon platinum +foil the fused portion floats down from the sides, and the foil is +coated around the undissolved part, with a thin, dark-red sublimate. +When fused upon charcoal, and in the reduction flame, it is reduced +with soda to a grey powder, which is attracted by the magnet, and +exhibits the metallic lustre by compression. + +_Sesquioxide of Cobalt_ (Co^{2}O^{3}).--It is a dark brown powder. Its +hydrate (2HO + Co^{2}O^{3}) is a brown powder. It is soluble only in +acetic acid as the acetate of the sesquioxide. All other acids +dissolve its salts to protoxide, the hydrochloric acid producing +chloric gas. By ignition in the oxidation flame, it is converted into +the proto-sesquioxide (CoO + Co^{2}O^{3}) and produces with reagents +before the blowpipe the same reactions as the protoxide. + +(_c._) _Nickel_ (Ni).--This metal occurs invariably associated with +cobalt, and in analogous combinations, chiefly as the arsenical +nickel. In the metallic state it is greyish, silver-white, has a high +lustre, is hard, and malleable both cold and hot. At common +temperatures, it is unalterable either in dry or moist air. When +ignited, it tarnishes. It is easily dissolved by nitric acid, but very +slowly by dilute sulphuric or hydrochloric acid, producing hydrogen. + +_Protoxide of Nickel _(NiO).--It is in the form of small greyish-black +octahedrons, or a dark, greenish-grey powder. Its hydrate is a green +powder. Both are unalterable in the air, and are soluble in nitric, +sulphuric, and hydrochloric acids, to a green liquid. The protoxide is +the base of the salts of nickel, which in the anhydrous state are +yellow, and when hydrated are green. The soluble neutral salts change +blue litmus paper to red. By ignition in the oxidation flame, +protoxide of nickel is unaltered. In the reduction flame and upon +charcoal, it becomes reduced, and forms a grey adherent powder, which +is infusible, and presents the metallic lustre by compression, and is +magnetic. Borax dissolves it in the oxidation flame very readily to a +clear bead, of a reddish-violet or dark yellow color, but yellow or +light red when cold. If there is but a small quantity of the oxide +present, it is colorless. If more of the oxide be present, the bead is +opaque and dark brown, and appears, while cooling, transparent and +dark red. By the addition of a salt of potassa (the nitrate or +carbonate) a blue or a dark purple colored bead is produced. The borax +bead, in the reduction flame, is grey, turbid, or completely opaque +from the reduced metallic particles. After a continued blast, the bead +becomes colorless, although the particles are not fused. If the nickel +contains cobalt, it will now be visible with its peculiar blue color. +Upon charcoal, and by the addition of some tin, the reduction of the +oxide of nickel is easily effected, while the reduced nickel fuses +with the tin. + +The oxide of nickel is dissolved by microcosmic salt in the oxidation +flame to a clear bead, which appears reddish while hot, but yellow and +sometimes colorless when cooling. If a considerable quantity of nickel +be present the heated bead is of a brown color, but orange when +cooled. In the reduction flame, and upon platinum wire, the color of +the bead is orange when cold; but upon charcoal, and with the addition +of a little tin, the bead appears grey and opaque. After being +submitted to the blowpipe flame all the nickel is reduced, and the +bead becomes colorless. + +Carbonate of soda does not affect it in the oxidation flame, but in +the reduction flame and upon charcoal, it is absorbed and reduced, and +remains, after washing off the carbon, as a white metallic powder, +which is infusible, and has a greater attraction for the magnet than +iron. + +_Sesquioxide of Nickel_ (Ni^{2}O^{3}).--It is in the form of a black +powder, and does not combine with other substances, unless it is +reduced to the protoxide. It exhibits before the blowpipe the same +behavior as the protoxide. + + +GROUP SIXTH.--ZINC, CADMIUM, ANTIMONY, TELLURIUM. + +The substances of this group can be reduced upon charcoal by fusion +with carbonate of soda, but the reduced metals are volatilized, and +cover the charcoal with sublimates. + +(_a._) _Zinc_ (Zn).--This metal is found in considerable abundance, +but never occurs in the pure metallic state, but in combination with +other substances, chiefly as sulphide in zinc blende, as carbonate in +calamine, and as the silicate in the kieselzinc ore; also, with +sulphuric acid, the "vitriol of zinc." + +Zinc is of a bluish-white color and metallic lustre, is crystalline +and brittle when heated 400°F., but malleable and ductile between 200° +and 300°. It will not oxidize in dry air, but tarnishes if exposed to +air containing moisture, first becomes grey, and then passes into the +white carbonate. It decomposes in water at a glowing heat. It is +dissolved by diluted acids, while hydrogen is eliminated. It melts at +about 775°, and distills when exposed to a white heat in a close +vessel. When heated over 1000° in the open air, it takes fire, and +burns with a bluish-white light, and with a thick white smoke of oxide +of zinc. + +_Oxide of Zinc_ (ZnO).--In the pure state, oxide of zinc is a white +powder, infusible, and not volatile. It is readily soluble in acids +after being heated strongly. Its soluble neutral salts, when dissolved +in water, change blue litmus paper to red. Its salts, with organic +acids, are decomposed by ignition, and the carbonate of zinc remains. + +The oxide of zinc turns yellow by being ignited in the oxidation +flame, but it is only visible by daylight; this color changes to white +when cold. It does not melt, but produces a strong light, and it is +not volatile. + +It disappears gradually in the flame of reduction, while a white smoke +sublimates upon the charcoal. This sublimate is yellow while hot, but +changes to white when cold. The cause of this is, that the oxide is +reduced, is volatilized, and re-oxidized, by going through the +external flame in the form of a metallic vapor. + +Borax dissolves oxide of zinc in the flame of oxidation easily to a +clear bead, which is yellow while hot, and colorless when cold. The +bead becomes, by the addition of more oxide, enamelled, while cooling. +If the bead is heated with the intermittent flame, it is milk-white +when cold. When heated in the flame of reduction upon platinum wire, +the bead at first appears opaque, and of a greyish color, but becomes +clear again after a continued blast. + +When heated upon charcoal in the reduction flame, it is reduced to a +metal; but, at the same moment, is volatilized, and sublimes as oxide +of zinc upon the charcoal, about one line's distance from the assay. +This is likewise the case with the microcosmic salt, except that it is +more easily volatilized in the reduction flame. + +Carbonate of soda does not dissolve the oxide of zinc in the flame of +oxidation. In the reduction flame and upon charcoal, the oxide of zinc +is reduced to the metallic state, and is volatilized with a white +vapor of the zinc oxide, which sublimes on the charcoal and exhibits a +yellow color while hot, and which changes to white when cold. By a +strong heat the reduced zinc burns with a white flame. + +Moistened with a solution of cobalt oxide, and heated strongly in the +flame of oxidation, zinc oxide becomes of a yellowish-green color +while hot, and changes to a beautiful green color when cold. + +(_b._) _Cadmium_ (Cd).--This is one of the rare metals. It occurs in +combination with sulphur in _greenockite_, and in some ores of zinc. +It was detected first in the year 1818, and presents itself as a +tin-white metal of great lustre, and susceptible of a fine polish. It +has a fibrous structure, crystallizes easily in regular octahedrons, +presenting often the peculiar arborescent appearance of the fern. It +is soft, but harder and more tenacious than tin; it can be bent, +filed, and easily cut: it imparts to paper a color like that of lead. +It is very malleable and ductile, and can be hammered into thin +leaves. It is easily fused, and melts before it glows (450°). At a +temperature not much over the boiling point of mercury, it begins to +boil, and distills, the vapor of the metal possessing no peculiar +odor. It is unalterable in the air for a long time, but at length it +tarnishes and presents a greyish-white, half metallic color. This +metal easily takes fire when heated in the air, and burns with a +brownish-yellow vapor, while it deposits a yellow sublimate upon +surrounding bodies. It is easily soluble in acids with the escape of +hydrogen, the solutions being colorless. Its salts, soluble in water, +are decomposed by ignition in free air. Its soluble neutral salts +change blue litmus paper to red. The salts, insoluble in water, are +readily dissolved in acids. + +_Oxide of Cadmium_ (CdO).--This oxide is of a dark orange color. It +does not melt, and is not volatile, not even at a very high +temperature. Its hydrate is white, loses in the heat its hydratic +water, and absorbs carbonic acid from the air when it is kept in open +vessels. + +Cadmium oxide is unaltered when exposed upon platinum wire in the +flame of oxidation. When heated upon charcoal in the flame of +reduction it disappears in a very short time, while the charcoal is +coated with a dark orange or yellow powder, the color of which is more +visible after it is cooled. The portions of this sublimate furthest +from the assay present a visible iridescent appearance. This reaction +of cadmium is so characteristic and sensitive that minerals (for +instance, calamine, carbonate of zinc) which contains from one to five +per cent. of carbonate of cadmium, will give a dark yellowish ring of +cadmium oxide, a little distance from the assay, after being exposed +for a few moments to the flame of reduction. This sublimate is more +visible when cold, and is produced some time previous to the reduction +of the zinc oxide. If a vapor of the latter should appear, it +indicates that it has been exposed too great a length of time to the +flame. + +Borax dissolves a considerable quantity of cadmium oxide upon a +platinum wire to a clear yellow bead, which, when cold, is almost +colorless. If the bead is nearly saturated with the cadmium oxide, it +appears milk-white when intermittingly heated. If the bead is +completely saturated, it retains its opalescent appearance. Upon +charcoal, and in the flame of reduction, the bead intumesces, the +cadmium oxide becomes reduced to metal; this becomes volatilized and +re-oxidized, and sublimes upon the charcoal as the yellow cadmium +oxide. + +In the oxidation flame, microcosmic salt dissolves a large quantity of +it to a clear bead, which, when highly saturated and while hot, is +yellowish colored, but colorless when cold. By complete saturation, +the bead is enamel-white when cold. + +Upon charcoal, in the flame of reduction, the bead is slowly and only +partially reduced, a scanty sublimate being produced on the charcoal. +The addition of tin promotes the reduction. + +Carbonate of soda does not dissolve cadmium oxide in the oxidation +flame. In the reduction flame, upon charcoal, it is reduced to metal, +and is volatilized to a red-brown or dark, red sublimate of cadmium +oxide upon the charcoal, at a little distance from the assay the +charcoal presenting the characteristic iridescent appearance. This +reaction is still more sensitive if the cadmium oxide is heated _per +se_ in the reduction flame. + +_Antimony_ (Sb).--This metal is found in almost every country. It +principally occurs as the tersulphide (SbS^{3}), either pure or +combined with other sulphides, particularly with basic sulphides. +Sometimes it occurs as the pure metal, and rarer in a state of +oxidation as an antimonious acid and as the oxysulphide. + +In the pure state, antimony has a silver-white color, with much +lustre, and presents a crystalline structure. The commercial and +impure metal is of a tin-white color, and may frequently be split in +parallel strata. It is brittle and easily pulverized. It melts at a +low red heat (810°), is volatilized at a white heat, and can be +distilled. At common temperatures it is not affected by the air. At a +glowing heat it takes fire, and burns with a white flame, and with +white fumes, forming volatile antimonious acid. Common acids oxidize +antimony, but dissolve it slightly. It is soluble in aqua regia +(nitro-hydrochloric acid). + +_Sesquioxide of Antimony_ (Sb^{2}O^{3}).--In the pure state this oxide +is a white powder, is fusible at a dull red heat to a yellow liquid, +which, after cooling, is greyish-white and crystalline. If it is +heated excluded from the air, it can be volatilized completely; it +sublimes in bright crystals having the form of needles. It occurs +sometimes in nature as white and very bright crystals. It takes fire +when heated in the open air, and burns with a white vapor to +antimonious acid. It fuses with the ter-sulphide of antimony to a red +bead. It is distinguished from the other oxides of antimony by the +readiness with which it is reduced to the metallic state upon +charcoal, and by its easy fusibility and volatility. + +The sesquioxide is the base of some salts--for instance, the tartar +emetic. It is not soluble in nitric acid, but is soluble in +hydrochloric acid. This solution becomes milky by the addition of +water. A part of the salts of the sesquioxide of antimony are +decomposed by ignition. The haloid salts are easily volatilized, +without decomposition. Its soluble neutral salts change blue litmus +paper to red, and are converted, by admixture of water, into +insoluble basic and soluble acid salts. + +Antimonious acid (antimoniate of sesquioxide of antimony, Sb^{2}O^{3} ++ Sb^{2}O^{5}) is of a white color, but, when heated, of a light +yellow color, but changes to white again when cold. It is infusible +and unaltered by heat. It forms a white hydrate, and both are +insoluble in water and nitric acid. It is partly soluble in +hydrochloric acid, with the application of heat. The addition of water +causes a precipitate in this solution. + +_Antimonic Acid _(Sb^{2}O^{5}).--In the pure state this acid is a +light yellow-colored powder. Its hydrate is white, and is insoluble in +water and nitric acid. It is sparingly soluble in hot concentrated +hydrochloric acid. It forms salts with every base, some of which are +insoluble, and others sparingly so. Notwithstanding that antimonic +acid is insoluble in water, it expels the carbonic acid from the +solutions of the carbonates of the alkalies. Antimonic acid and its +hydrate changes moistened blue litmus paper to red. + + +_Behavior of Antimony and its Oxides before the Blowpipe._ + +_Metallic Antimony_ fuses easily upon charcoal. When heated to +glowing, and then removed from the flame, it continues to glow for +awhile, and produces a thick white smoke. The vapor crystallizes +gradually, and coats the assay with small crystals which iridesce like +mother of pearl (sesquioxide of antimony). It is not volatile at the +temperature of melted glass. Ignited in an open glass tube, it burns +slowly with a white vapor, which condenses upon the cool part of the +tube, and exhibits some indications of crystallization. This vapor +consists of the sesquioxide, and can be driven by heat from one place +to another, without leaving a residue. If the metallic antimony +contains sulphide of antimony, there is a corresponding portion of +antimonious acid produced, which remains as a white sublimate after +the sesquioxide is removed. + +_Sesquioxide of antimony_ melts easily, and sublimes as a white vapor. +It may be prepared by precipitating and drying. When heated, it takes +fire previous to melting, glows like tinder, and is converted into +antimonious acid, which is now infusible. When heated upon charcoal in +the flame of reduction, it is reduced to the metallic state, and +partly volatilized. A white vapor sublimates upon the charcoal, while +the external flame exhibits a greenish-blue color. Antimonious acid is +infusible, produces a strong light, and is diminished in volume when +heated in the external flame, during which time a dense white vapor +sublimes upon the charcoal. It is not, however, in this manner reduced +to the metallic state like the sesquioxide. + +_Antimonic acid_, when first heated, becomes white, and is converted +into antimonious acid. Hydrated antimonic acid, which is originally +white, appears at first yellow while giving off water, and then +becomes white again, while oxygen is expelled, and it is converted +into antimonious acid. + +The oxides of antimony produce, with blowpipe reagents, the following +reactions: borax dissolves oxides of antimony in the oxidation flame +in considerable quantity to a clear bead, which is yellow while hot, +but colorless when cold. If the bead is saturated, a part of the oxide +is volatilized as a white vapor. Upon charcoal, in the oxidation +flame, it is completely volatilized, and the charcoal is covered with +a white sublimate. Heated upon charcoal in the reducing flame, the +bead is of a greyish color, and partially, if not wholly opaque, from +the presence of reduced metallic particles. A continued heat will +volatilize them, and the bead becomes clear. The addition of tin +promotes the reduction. + +Microcosmic salt dissolves the compounds of antimony in the flame of +oxidation with intumescence, to a clear light-yellow colored bead, +which when cold is colorless. Heated upon charcoal in the reduction +flame, the bead is first turbid, but soon becomes transparent. The +addition of tin renders the bead greyish while cooling, but a +continued blast renders it transparent. Soda dissolves the compounds +of antimony upon platinum wire in the oxidation flame, to a clear +colorless bead, which is white when cold. + +Upon charcoal, both in the oxidation and reduction flames, the +antimony compounds are readily reduced to the metal, which is +immediately volatilized, and produces a white incrustation of oxide of +antimony upon the charcoal. If the antimony compounds are heated upon +charcoal in the flame of reduction, with a mixture of carbonate of +soda and cyanide of potassium (KCy), there are produced small globules +of metallic antimony. At the same time, a part of the reduced metal is +volatilized (this continues after the assay is removed from the flame) +and re-oxidized. A white incrustation appears upon the charcoal, and +the metallic globules are covered with small white crystals. If this +white sublimate upon the charcoal is moistened with a solution of +cobalt-oxide, and exposed to the reduction flame, a part of it is +volatilized, while the other part passes into higher oxidation, and +remains, after cooling, of a dirty dark-green color. + +(_d._) _Tellurium_ (Te).--This is one of the rare metals. It occurs +very seldom in the metallic state, but often with bismuth, lead, +silver, and gold. Tellurium, in the pure state, is silver-white, very +bright, of a foliated or lamellar structure, brittle, and easily +triturated. It is inclined to crystallize. It is soluble in +concentrated sulphuric acid without oxidation. The solution is of a +fine purple color, and gives a precipitate with the addition of water. + +_Tellurium in the Metallic form._--By the aid of heat it is oxidized +in sulphuric acid, a portion of the oxygen of the acid oxidizing the +metal, while sulphurous acid gas escapes. This solution is colorless, +and is tellurous acid, dissolved in sulphuric acid. It melts at a low +red heat, and volatilizes at a higher temperature. If tellurium is +heated with free access of air, it takes fire, and burns with a blue +color, the flame being greenish at the edges, while a thick white +vapor escapes, which has a feeble acidulous odor. + +_Tellurous Acid_ (TeO^{2}) is of a fine, granulous, crystalline or +white earthy mass, which is partly soluble in water. The solution has +a strong metallic taste, and an acid reaction upon litmus paper. +Heated in a tube closed at one end until it begins to glow, it fuses +to a yellow liquid which is colorless, crystalline, and opaque when +cold. Beads of it remain usually transparent like glass. Heated upon +platinum wire in the flame of oxidation, it melts, and is volatilized +as a white vapor. When heated upon charcoal in the oxidation flame, it +melts, and is reduced to the metallic state, but volatilizes and a +sublimate of white tellurous acid is formed upon the charcoal. The +edge of this deposit is usually red or dark-yellow. + +Heated upon charcoal in the flame of reduction, it is rapidly reduced, +the external flame exhibiting a bluish-green color. + +Borax dissolves it in the oxidation flame upon platinum wire to a +clear colorless bead which turns grey when heated upon charcoal, +through the presence of reduced metallic particles. Upon charcoal, in +the reduction flame, the bead is grey, caused by the reduced metal. +After a continued blast, tellurium is completely volatilized, and the +bead appears clear again, while a white sublimate is deposited upon +the charcoal. + +With microcosmic salt, the same reactions are produced. + +With carbonate of soda, tellurous acid fuses upon platinum wire to a +clear colorless bead, which is white when cold. Upon charcoal it is +reduced, and forms _tellur-sodium_, which is absorbed by the charcoal, +and metallic tellurium, which is volatilized, and deposits upon the +charcoal a white incrustation (tellurous acid). + +If tellurous acid, finely powdered charcoal, and carbonate of soda are +mixed together, and the mixture be well ignited in a closed tube, +until fusion is effected, and a few drops of boiled water are brought +into the tube, they are colored purple, indicating the presence of +_tellur-sodium._ + +_Telluric Acid _(TeO^{3}) forms six-sided prismatic crystals. It has +not an acid, but rather a metallic taste. It changes blue litmus paper +to red; is slowly soluble in water, and rather sparingly. Exposed to +a high temperature, but not until glowing, the crystalline acid loses +its water, and acquires an orange color, but still it preserves its +crystalline form, although no longer soluble in water, and is in fact +so much changed in its properties as to present the instance of an +isomeric modification. + +If telluric acid is heated gently in a closed tube, it loses water and +turns yellow. Heated still more strongly, it becomes milk-white, +oxygen is expelled, and it is converted into tellurous acid. The +presence of oxygen can be recognized by the more lively combustion +which an ignited splinter of wood undergoes when held in it. Telluric +acid produces the same reactions with the blowpipe reagents as +tellurous acid. + + +SEVENTH GROUP.--LEAD, BISMUTH, TIN. + +The oxides of these metals are also reduced to the metallic state by +fusion with soda upon charcoal in the flame of reduction, but they are +volatilized only after a continued blast, and a sublimate is thrown +upon the charcoal. + +(_a._) _Lead_ (Pb).--This metal occurs in considerable quantity in +nature, chiefly as galena or lead-glance (sulphide of lead). Likewise, +but more rarely, as a carbonate; also as a sulphate, and sometimes +combined with other acids and metals. + +In the metallic state, lead is of a bluish-grey color, high lustre, +and sp. gr. 11.4. It is soft, and communicates a stain to paper. It is +malleable, ductile, but has very little tenacity. It melts at about +612°. Exposed to the air it soon tarnishes, being covered with a grey +matter, which some regard as a suboxide (Pb^{2}O), and others as +simply a mixture of lead and protoxide. At a glowing heat it is +oxidized to a protoxide, and at a white heat it is volatilized. It is +insoluble in most acids. It is, however, soluble in nitric acid, but +without decomposing water. + +(_L._) _Protoxide of Lead_ (PbO).--It is an orange-colored powder, +which melts at a glowing temperature, and forms a lamellar mass after +cooling. Protoxide of lead absorbs oxygen from the atmosphere while +melting, which is given off again by cooling. Being exposed for a +longer while to the air, it absorbs carbonic acid and water, and +becomes white on the surface. It is soluble in nitric acid and caustic +alkalies. It forms with most acids insoluble salts. It is slightly +soluble in pure water, but not in water which contains alkaline salts. +This hydrate is white. + +([beta].) _Red Oxide of Lead_ (PbO^{2}, PbO).--It forms a puce-colored +powder. It is insoluble in caustic alkalies. Hydrochloric acid +dissolves it and forms a yellow liquid, which is soon decomposed into +chloride of lead and chlorine. It is reduced by ignition to the +protoxide. + +([gamma].) _Peroxide of Lead _(PbO^{2}).--It is a dark-brown powder. +It yields with hydrochloric acid the chloride of lead and chlorine +gas. When heated it liberates oxygen, and is reduced to the protoxide. + +Lead combinations give the following reactions before the blowpipe: +Metallic lead tarnishes when heated in the oxidation flame, and is +instantly covered with a grey matter, consisting of the protoxide and +the metal. It fuses quickly, and is then covered with a +yellowish-brown protoxide until all the lead is converted into the +protoxide, which melts to a yellow liquid. In the reduction flame and +upon charcoal, it is volatilized, while the charcoal becomes covered +with a yellow sublimate of oxide. A little distance from the assay, +this sublimate appears white (carbonate of lead). Protoxide of lead +melts in the flame of oxidation to a beautiful dark yellow bead. In +the flame of reduction, and upon charcoal, it is reduced with +intumescence to metallic lead, which is volatilized by a continued +blast, and sublimates on charcoal, as mentioned above. + +Red oxide of lead turns black when heated in the glass tube closed at +one end, and liberates oxygen, which is easily detected by the +introduction of an ignited splinter, when a more lively combustion of +the wood proves the presence of uncombined oxygen. The red oxide in +this case is reduced to the protoxide. Heated upon platinum foil, it +first turns black, is reduced to the protoxide, and melts into a dark +yellow liquid. In the reduction flame, upon charcoal, it is reduced to +the metal with intumescence. After a continued blast, a yellow +sublimate of protoxide is produced upon the charcoal, and at a little +distance off, around this sublimate, a white one of carbonate of lead +is produced. This sublimate disappears when touched by the flame of +reduction, while it communicates an azure blue-tinge to the external +flame. This is likewise the case with the peroxide of lead. + +The different oxides of lead produce with the blowpipe reagents the +same reactions. + +_Borax_ dissolves lead compounds with the greatest readiness upon +platinum wire in the oxidation flame to a transparent bead, which is +yellow when hot, but colorless after being cooled. With the addition +of more of the lead oxide, it becomes opalescent. When heated by the +intermittent flame, and with still more of the oxide, it acquires a +yellow enamel after cooling. Heated upon charcoal, in the flame of +reduction, the bead spreads and becomes opaque. After a continued +blast, all the oxide is reduced with effervescence to metallic lead, +which melts and runs towards the edges of the bead, while the bead +again becomes transparent. + +_Microcosmic Salt_ dissolves oxides of lead upon platinum wire in the +flame of oxidation easily to a clear, colorless bead, which appears, +when highly saturated, yellow while hot. A saturated bead becomes +enamel-like after cooling. The bead appears in the flame of reduction, +and upon charcoal, of a greyish color and dull. By the addition of +more oxide, a yellow sublimate of protoxide is produced upon the +charcoal. By the addition of tin, the bead appears of a darker grey, +but it is never quite opaque. + +_Carbonate of Soda_ dissolves oxide of lead in the flame of oxidation +upon platinum wire quite readily to a transparent bead, which becomes +yellow when cooling, and is opaque. Upon charcoal in the flame of +reduction, it is rapidly reduced to metallic lead, which yields, +after a continued blast, a yellow sublimate of oxide upon the +charcoal. + +(_b._) _Bismuth_ (Bi).--This metal occurs mostly in the metallic +state, and less frequently as the sulphide. In the pure metallic +state, it is of a reddish-white color and great lustre. It +crystallizes in cubes. It is brittle, and may be readily pulverized. +It melts at 476°, and is volatilized at a white heat. It is soluble in +nitric acid, and forms the nitrate of bismuth. + +([alpha].) _Oxide of Bismuth _(Bi^{2}O^{3}).--This oxide is a light +yellow powder, fusible at a red heat, insoluble in caustic potash and +ammonia. It is the base of the salts of bismuth. Its hydrate is white, +and easily soluble in acids. The addition of water causes these +solutions to become milky, because they are decomposed into a soluble +acidulous and an insoluble basic salt of bismuth. + +([beta].) _Peroxide of Bismuth_ (BiO^{2}) is a dark-colored powder, +completely soluble in boiling nitric acid, and yielding oxygen; +produces, with hydrochloric acid, chlorine gas. It can be heated up to +the temperature of 620° without being decomposed; but, exposed to a +temperature of 630° it yields oxygen. Mixed with combustible +substances, it glows with brightness. + +([gamma].) _Bismuthic Acid _(Bi^{2}O^{5}) is a brown powder similar to +the peroxide, but is converted by boiling nitric acid into a green, +scarcely soluble substance (Bi^{2}O^{3}, Bi^{2}O^{5}). Its hydrate is +of a red color. + +BLOWPIPE REACTIONS.--Metallic bismuth is converted, when exposed upon +platinum wire to the flame of oxidation, into a dark brown oxide, +which turns light yellow while cooling. It is slowly volatilized when +heated, and a yellow sublimate of oxide is produced upon the charcoal. + +Oxide of bismuth melts upon platinum foil in the flame of oxidation +very easily into a dark-brown liquid, which changes to a light yellow +while cooling. By too strong a heat, it is reduced and penetrates the +platinum foil. + +Upon charcoal, in the flame of oxidation and of reduction, it is +reduced to metallic bismuth, which melts into one or more globules. +By a continued blast they are slowly volatilized, and produce a yellow +sublimate of oxide upon the charcoal, beyond which a white sublimate +of carbonate of bismuth is visible. These sublimates disappear in the +flame of reduction, but without communicating any color to it. + +_Borax_ dissolves oxide of bismuth upon platinum wire, in the flame of +oxidation, easily to a clear yellow bead, which appears colorless +after cooling. By the addition of more oxide, the hot bead becomes +orange. It turns more yellow while cooling, and when cool is +opalescent. Upon charcoal in the flame of reduction, the bead becomes +turbid and greyish colored. The oxide is reduced with intumescence to +the metallic state, and the bead becomes clear again. The addition of +tin promotes the reduction. + +_Microcosmic Salt_ dissolves oxide of bismuth upon platinum wire, in +the flame of oxidation, to a yellow bead, which becomes colorless +after cooling. By the addition of more oxide, the bead is +yellowish-brown while hot, and colorless after cooling, but not quite +transparent. This bead becomes enamelled when heated by the +intermittent flame; also, by the addition of still more of the oxide, +after it is cooled. + +Upon charcoal, in the flame of reduction, and particularly with the +addition of tin, the bead is colorless and transparent while hot, but +while cooling becomes of a dark-gray color and opaque. + +Oxide of bismuth is reduced, by fusion with carbonate of soda, as well +in the oxidating as in the reducing flame, instantly to metallic +bismuth. + +As the above mentioned higher oxides of bismuth are converted by +ignition into oxide of the metal and free oxygen, they have the same +behavior before the blowpipe. + +As bismuth occurs mostly in the metallic form, it is necessary to know +how to distinguish it from metals similar to it. Its brittleness +distinguishes it from lead, zinc and tin, as they are readily +flattened by a stroke of the hammer, while bismuth is broken to +pieces. Bismuth, in this latter respect, might perhaps be mistaken +for antimony or tellurium; but, by the following examination, it is +easy to separate bismuth from antimony or tellurium. + +1. Neither bismuth nor antimony sublimates when heated in a glass tube +closed at one end. At a temperature which is about to fuse the glass, +tellurium yields a small quantity of a white vapor (some tellurium is +oxidized to tellurous acid by the oxygen of the air in the tube). +After that, a grey metallic sublimate settles on the sides of the +tube. + +2. Heated in an open tube, antimony yields a white vapor, which coats +the inside of the glass tube, and can be driven by heat from one part +of the tube to another without leaving a residue. The metallic globule +is covered with a considerable quantity of fused oxide. Tellurium +produces, under the same circumstances, an intense vapor, and deposits +on the glass a white powder, which melts by heat into globules that +run over the glass. The metallic globules are covered by fused, +transparent, and nearly colorless oxide, which becomes white while +cooling. By a high temperature, and with little access of air, +metallic tellurium sublimes with the deposition of a grey powder. +Bismuth produces, under similar treatment, scarcely any vapor, unless +it is combined with sulphur. The metal is enveloped by fused oxide of +a dark yellow color, which appears light yellow after being cooled. It +acts upon the glass, and dissolves it. + +3. Upon charcoal, exposed to the blowpipe flame, the three metals are +volatilized, and yield a sublimate upon the charcoal. That of antimony +is white, while those of bismuth and tellurium are dark yellow. By +exposing them to the flame of reduction, the sublimate of tellurium +disappears and communicates an intense green color to the flame. The +antimony incrustation gives a feeble greenish-blue color, while the +sublimate of bismuth gives no perceptible color in the light. It is, +however, worthy of notice that if the operation takes place in the +dark, a very pale blue flame will be seen with the bismuth. + +(_c._) _Tin_ (Sn).--This metal does not occur in nature in the +metallic state, very seldom in the sulphide, but chiefly in the oxide +(tinstone). In the metallic state it is silver-white, possesses a very +high lustre, is soft (but harder than lead), ductile, but has not much +tenacity, and it is very malleable. The metal when it is cast gives a +peculiar creaking noise when twisted or bent, which proceeds from the +crystalline structure of the metal. This crystallization is quite +clearly manifested by attacking the surface of the metal, or that of +tin plate, with acids. + +Tin is very slightly tarnished by exposure to the air. It fuses at +442°, and becomes grey, being a mixture of the oxide and the metal. At +a high temperature even, tin is but little subject to pass off as +vapor. It is soluble in aqua regia, and with the liberation of +hydrogen, in hot sulphuric and hydrochloric acids, and in cold dilute +nitric acid, without decomposing water, or the production of a gas, +while nitrate of tin and nitrate of ammonia are formed. Concentrated +nitric acid converts tin into insoluble tin acids. + +([alpha].) _Protoxide of Tin_ (SnO) is a dark-grey powder. Its hydrate +is white, and is soluble in caustic alkalies. When this solution is +heated, anhydrous crystalline black protoxide is separated. The +soluble neutral salts of tin-protoxide are decomposed by the addition +of water, and converted into acid soluble, and basic insoluble salts. + +When protoxide of tin is ignited with free access of air, it takes +fire and is converted with considerable intensity into the acids, +producing white vapors. This is likewise the case if it is touched by +a spark of fire from steel. The hydrate of the protoxide of tin can be +ignited by the flame of a candle, and glows like tinder. + +([beta].) _Sesquioxide of Tin_ (Sn^{2}O^{3}) is a greyish-brown +powder. Its hydrate is white, with a yellow tinge. It is soluble in +aqua ammonia and in hydrochloric acid; this solution forms with +solution of gold the "purple of Cassius." + +([gamma].) _Stannic Acid_ (peroxide, SnO^{2}).--This acid occurs in +nature crystallized in quadro-octahedrons, of a brown or an intense +black color, and of great hardness (tinstone). Artificially prepared, +it is a white or yellowish-white powder. It exists in two distinct or +isomeric modifications, one of which is insoluble in acids (natural +tin-acid) while the other (tin-acid prepared in the wet way) is +soluble in acids. By ignition the soluble acid is converted into the +insoluble. Both modifications form hydrates. + +_Reactions before the Blowpipe._--Metallic tin melts easily. It is +covered in the flame of oxidation into a yellowish-white oxide, which +is carried off sometimes by the stream of air which propels the flame. +In the reduction flame, and upon charcoal, melting tin retains its +metallic lustre, while a thin sublimate is produced upon the charcoal. +This sublimate is light-yellow while hot, and gives a strong light in +the flame of oxidation, and turns white while cooling. This sublimate +is found near to the metal, and cannot be volatilized in the oxidation +flame. In the flame of reduction it is reduced to metallic tin. +Sometimes this incrustation is so imperceptible that it can scarcely +be distinguished from the ashes of the charcoal. If such be the case, +moisten it with a solution of cobalt, and expose it to the flame of +oxidation, when the sublimate will exhibit, after cooling, a +bluish-green color. + +Protoxide of tin takes fire in the flame of oxidation, and burns with +flame and some white vapor into tin acid, or stannic acid. In a strong +and continued reduction flame, it may be reduced to metal, when the +same sublimate above mentioned is visible. The sesquioxide of tin +behaves as the above. + +Stannic acid, heated in the flame of oxidation, does not melt and is +not volatilized, but produces a strong light, and appears yellowish +while hot, but changing as it cools to a dirty-yellow white color. In +a strong and continued flame of reduction, it may be reduced likewise +to the metallic state, with the production of the same sublimate as +the above. + +_Borax_ dissolves tin compounds in the flame of oxidation, and upon +platinum wire, very tardily, and in small quantity, to a transparent +colorless bead, which remains clear after cooling, and also when +heated intermittingly. But if a saturated bead, after being completely +cool, is exposed again to the flame of oxidation, at a low red heat, +the bead while cooling is opaque, loses its globular form, and +exhibits an indistinct crystallization. This is the case too in the +flame of reduction, but if the bead is highly saturated, a part of the +oxide is reduced. + +_Microcosmic Salt_ dissolves the oxides in the flame of reduction very +tardily in a small quantity to a transparent colorless bead, which +remains clear while cooling. If to this bead sesquioxide of iron is +added in proper proportion, the sesquioxide loses its property of +coloring the bead, but of course an excess of the iron salt will +communicate to the bead its own characteristic color. In the flame of +reduction no further alteration is visible. + +Tin-oxides combine with carbonate of soda, in the flame of oxidation +upon platinum wire, with intumescence to a bulky and confused mass, +which is insoluble in more soda. Upon charcoal, in the reduction +flame, it is easily reduced to a metallic globule. Certain compounds +of tin-oxides, particularly if they contain tantalum, are by fusion +with carbonate of soda reduced with difficulty; but by the addition of +some borax, the reduction to the metallic state is easily effected. + +Tin-oxides exposed to the oxidation flame, then moistened with a +solution of cobalt, and exposed again to the flame of oxidation, will +exhibit, after having completely cooled, a bluish-green color. + + +EIGHTH GROUP.--MERCURY, ARSENIC. + +These two metals are volatilized at a temperature lower than that of a +red heat, and produce, therefore, no reactions with borax and +microcosmic salt. Their oxides are easily reduced to the metallic +state. + +(_a._) _Mercury_ (Hg).--This metal occurs in nature chiefly combined +with sulphur as a bisulphide. + +It occurs still more rarely in the metallic form, or combined with +silver, selenium, or chlorine. + +Mercury, in the metallic state, has a strong lustre, and is liquid at +ordinary temperatures, whereby it is distinguished from any other +metal. It freezes at 40° and boils at 620°, but it evaporates at +common temperatures. Pure mercury is unalterable. Upon being exposed +to the air, it tarnishes only by admixture with other metals, turns +grey on the surface, and loses its lustre. It is soluble in cold +nitric acid and in concentrated hot sulphuric acid, but not in +hydrochloric acid. + +([chi].) _Protoxide of Mercury_ (Hg^{2}O).--It is a black powder, +which is decomposed by ignition into metallic mercury and oxygen. By +digestion with certain acids, and particularly with caustic alkalies, +it is converted into metallic mercury and peroxide. Some neutral salts +of the protoxide are only partly soluble in water, as they are +converted into basic insoluble and acid soluble salts. + +Protoxide of mercury is completely insoluble in hydrochloric acid. Its +neutral salts change blue litmus paper to red. + +([beta].) _Peroxide of Mercury_ (HgO).--This oxide exists in two +allotropic modifications. One is of a brick-red color, and the other +is orange. Being exposed to heat, they turn black, but regain their +respective colors upon cooling. They are decomposed at a high +temperature into metallic mercury and oxygen. They yield with acids +their own peculiar salts. + +Mercury, in the metallic form, can never be mistaken for any other +metal in consequence of its fluid condition at ordinary temperatures. + +Exposed to the blowpipe flame, it is instantly volatilized. This is +also the case with it when combined with other metals. The oxides of +mercury are, in the oxidation and reduction flames, instantly reduced +and volatilized. They do not produce any alteration with fluxes, as +they are volatilized before the bead melts. Heated with carbonate of +soda in a glass tube closed at one end, they are reduced to metallic +mercury, which is volatilized, and condenses upon a cool portion of +the tube as a grey powder. By cautious knocking against the tube, or +by rubbing with a glass rod, this sublimate can be brought together +into one globule of metallic mercury. Compounds of mercury can be most +completely reduced by a mixture of neutral oxalate of potassa and +cyanide of potassium. If the substance under examination contains such +a small quantity of mercury that it cannot be distinguished by +volatilization, a strip of gold leaf may be attached to an iron wire, +and introduced during the experiment in the glass tube. The smallest +trace of mercury will whiten the gold leaf in spots. + +(_b._) _Arsenic_ (As).--This metal occurs in considerable quantity in +nature, chiefly combined with sulphur or metals. + +Arsenic, in the metallic state, is of a whitish-grey color, high +lustre, and is crystalline, of a foliated structure, and is so brittle +that it can be pulverized. It does not melt, but is volatilized at +356°. Its vapor has a strong alliaceous odor. Arsenic sublimes in +irregular crystals. By exposure to the air it soon tarnishes, and is +coated black. Being mixed with nitrate of potassa and inflamed, it +detonates with vehemence. Mixed with carbonate of potassa, it is +inflamed by a stroke of the hammer, and detonates violently. + +Heated in oxygen gas, it is inflamed, and burns with a pale blue flame +to arsenious acid. + +([beta].) _Arsenious Acid_ (AsO^{3}).--This acid crystallizes in +octahedrons, or, when fused, forms a colorless glass, which finally +becomes opaque and enamel-like, or forms a white powder. It sublimes +without change or decomposition. When heated for a longer while below +the temperature of sublimation, it melts into a transparent, +colorless, tough glass. The opaque acid is sparingly soluble in cold +water, and still more soluble in hot water. It is converted, by +continued boiling, into the transparent acid, which is much more +soluble in water. Arsenious acid is easily dissolved by caustic +potassa. It is also soluble in hydrochloric acid. This acid occurs +associated with antimonious acid, protoxide of tin, protoxide of lead, +and oxide of copper. It occurs likewise in very small quantity in +ferruginous mineral springs. + +([gamma].)_Arsenic Acid_ (AsO^{5}) is a white mass, which readily +absorbs moisture and dissolves. It will not volatilize at a low red +heat, nor will it decompose. Exposed to a strong heat, it is +decomposed, yielding oxygen, and passing into arsenious acid. + +_Reactions before the Blowpipe._ + +Metallic arsenic, heated in a glass tube closed at one end, yields a +black sublimate of a metallic lustre, and at the same time gives out +the characteristic alliaceous odor. This is the case too with alloys +of arsenic, if there is a maximum quantity of arsenic present. + +When heated in a glass tube open at both ends, metallic arsenic is +oxidized to arsenious acid, which appears as a white crystalline +sublimate on the sides of the glass tube. This deposit will occur at +some distance from the assay, in consequence of the great volatility +of the arsenic. The sublimate can be driven from one place upon the +tube to another, by a very low heat. Alloys of arsenic are converted +into basic arseniates of metal oxides, while surplus arsenic is +converted into arsenious acid, which sublimes on the tube. If too much +arsenic is used for this experiment, a dark-brown incrustation will +sublime upon the sides of the tube which will give an alliaceous +smell. If this sublimate should be deposited near the assay, then it +resembles the white sublimate of arsenious acid. + +Heated upon charcoal, metallic arsenic is volatilized before it melts, +and incrusts the charcoal in the flame of oxidation as a white deposit +of arsenious acid. This sublimate appears sometimes of a greyish +color, and takes place at some distance from the assay. When heated +slightly with the blowpipe flame, this sublimate is instantly driven +away, and being heated rapidly in the reduction flame, it disappears +with a light blue tinge, while the usual alliaceous or garlic smell +may be discerned. + +Arsenious acid sublimes in both glass tubes very readily, as a white +crystalline sublimate. These crystals appear to be regular octahedrons +when observed under the microscope. Upon charcoal it instantly +volatilizes, and when heated, the characteristic garlic smell may be +observed. + +Arsenic acid yields, heated strongly in a glass tube closed at one +end, oxygen and arsenious acid, the latter of which sublimes in the +cool portions of the tube. Compounds of arsenic produce, in +consequence of their volatility, no reactions with fluxes. Being +heated upon charcoal with carbonate of soda, they are reduced to +metallic arsenic which may be detected by the alliaceous odor peculiar +to all the arsenic compounds when volatilized. + + +NINTH GROUP.--COPPER, SILVER, GOLD. + +These metals are not volatile, neither are their oxides. They are +reduced to the metallic state, by fusion with carbonate of soda, when +they melt to a metallic grain. The oxides of silver and gold are +reduced _per se_ to the metallic state by ignition. In the reduction +of the oxides of this group, no sublimate is visible upon the +charcoal. + +(_a._) _Copper_ (Cu).--This metal occurs in the metallic state, also +as the protoxide, and as oxides combined with acids in different salts +(carbonate of copper as malachite, etc.) The sulphide of copper is the +principal ore of copper occurring in nature. In the metallic state, +copper is of a red color, has great lustre and tenacity, is ductile +and malleable, and crystallizes in octahedrons and cubes. It melts at +a bright red heat, is more difficult than silver to fuse, but fuses +more readily than gold. It absorbs oxygen while melting. There arises +from its surface a fine dust of metallic globules, which are covered +with the protoxide. The surface of the metal is likewise covered with +the protoxide. Copper exposed to moist air tarnishes, and is +converted into hydratic carbonate of copper. When ignited in the open +air, it is soon covered with the brownish-red protoxide. + +([chi].) _Protoxide of Copper_ (Cu^{2}O).--This oxide occurs in +nature, crystallized in octahedrons of a ruby-red color, of a lamellar +structure, and transparent. Artificially prepared, it forms a powder +of the same color. It is decomposed by dilute acids into salts of +peroxide and metal. It is converted by ignition, with free access of +air, into peroxide. + +([beta].) _Oxide of Copper_ (CuO).--This oxide is a dark-brown or +black powder. It is dissolved by acids, with a blue or green-colored +solution. It is soluble in aqua ammonia, and the solution is of a dark +blue color. + +_Reactions before the Blowpipe._--Oxide of copper exposed upon +platinum wire to the inmost flame (the blue flame), communicates to +the external flame a green color. Heated upon charcoal in the +oxidation flame, it melts to a black ball, soon spreads over the +charcoal, and is partially reduced. + +Exposed to the reduction flame, at a temperature which will not melt +copper, it is reduced with a bright metallic lustre, but as soon as +the blast ceases, the surface of the metal becomes oxidized, and +appears dark brown or black. If the temperature is continued still +higher, it melts to a metallic grain. + +_Borax_ dissolves the oxide of copper in the flame of oxidation to a +clear green-colored bead, even if the quantity of oxide be quite +small, but by cooling, the bead becomes blue. In the flame of +reduction upon platinum wire, the bead soon becomes colorless, but +while cooling presents a red color (protoxide of copper). This bead is +opaque, but, if too much of the oxide is added, a part of it is +reduced to metal, which is visible by breaking the metallic grain. + +Upon charcoal, the oxide is reduced to the metal, and the bead appears +colorless after cooling. With the addition of some tin, the bead +becomes brownish-red and opaque after cooling. + +_Microcosmic Salt_ dissolves oxide of copper in the flame of oxidation +to a green bead, not so intensely colored as the borax bead. In the +reduction flame the bead, if pretty well saturated, becomes dark-green +while hot, and brownish-red when cool, opaque and enamel-like. If the +oxide is so little that no reaction is visible, by the addition of +some tin, the bead appears colorless while hot, and dark brownish-red +and opaque when cold. + +_Carbonate of Soda_ dissolves oxide of copper in the oxidation flame +upon platinum wire, to a clear, green bead, which loses its color when +cooling, and becomes opaque. + +Upon charcoal, it is reduced to the metal, the soda is absorbed by the +charcoal, and the metallic particles melt with sufficient heat to a +grain. + +(_b._) _Silver_ (Ag).--This metal occurs in nature in the metallic +state, and in combination with other metals, particularly with lead. +It also occurs as the sulphide in several mines. It crystallizes in +cubes and octahedrons; is of a pure white color, great lustre, is very +malleable and ductile, and is softer than copper, but harder than +gold. It is not oxidizable, neither at common temperatures nor at +those which are considerably higher. It is soluble in dilute nitric +acid, and in boiling concentrated sulphuric acid. + +([chi].) _Protoxide of Silver_ (Ag^{2}O).--It is a black powder. It is +converted by acids and ammonia into oxide and metal. + +([beta].) _Oxide of Silver_ (AgO).--It is a greyish-brown or black +powder, and is the base of the silver salts. With aqua ammonia, it is +converted into the black, fulminating silver. + +([gamma].) _Superoxide or Binoxide of Silver_ (AgO^{2}).--This oxide +occurs in black needles or octahedral crystals of great metallic +lustre. It is dissolved by the oxygen acids with the disengagement of +oxygen gas. + +_Behavior before the Blowpipe._--When exposed to the flames of +oxidation and reduction, the oxides of silver are instantly reduced to +the metallic state. + +_Borax_ dissolves silver-oxides upon platinum wire in the oxidation +flame but partially, while the other portion is reduced, the bead +appearing opalescent after cooling, in correspondence to the degree of +saturation. The bead becomes grey in the flame of reduction, the +reduced silver melting to a grain, and the bead is rendered clear and +colorless again. + +_Microcosmic Salt_ dissolves oxides of silver in the flame of +oxidation upon platinum wire to a transparent yellowish bead, which +presents, when much of the oxide is present, an opalescent appearance. + +In the flame of reduction, the reaction is analogous to that of borax. + +By fusion with carbonate of soda in the oxidation and reduction +flames, the silver oxides are instantly reduced to metallic silver, +which fuses into one or more grains. + +(_c._) _Gold_ (Au).--This metal occurs mostly in the metallic state, +but frequently mixed with ores, and with other metals. Gold +crystallizes in cubes and octahedrons, is of a beautiful yellow color, +great lustre, and is the most malleable and ductile of all the metals. +It melts at a higher temperature than copper, gives a green colored +light when fused, and contracts greatly when cooling. It does not +oxidize at ordinary temperatures, nor when heated much above them. It +is soluble in nitro-hydrochloric acid (_aqua regia_). + +([chi].) _Protoxide of Gold_ (Au^{2}O).--This oxide is a dark violet +colored powder which is converted by a temperature of 540° into +metallic gold and oxygen. It is only soluble in aqua regia. Treated +with hydrochloric acid, it yields the chloride of gold and the metal. +With aqua ammonia, it yields the fulminating gold, which is a blue +mass and very explosive. + +([chi].) _Peroxide of Gold_ (Au^{2}O^{3}).--This oxide is an +olive-green or dark brown powder, containing variable quantities of +water. Decomposed at 530°, it yields metallic gold and oxygen. + +_Reactions before the Blowpipe._--Oxides of gold are reduced, in both +the oxidation and reduction flames, to the metal, which fuses to +grains. + +_Borax_ does not dissolve it, but it is reduced to the metallic state +in this flux in either flame. The reduced metal fuses upon charcoal to +a grain. + +_Microcosmic Salt_ presents the same reactions as borax. + +When fused with soda, upon charcoal, the soda is absorbed, and the +gold remains as a metallic grain. + + +TENTH GROUP.--MOLYBDENUM, OSMIUM. + +These metals are not volatile, and are infusible before the blowpipe; +but some of their oxides are volatile, and can be reduced to an +infusible metallic powder. + +(_a._) _Molybdenum_ (Mo) occurs in the metallic state; also combined +with sulphur, or as molybdic acid combined with lead. It is a white, +brittle metal, and is unaltered by exposure to the air. When heated +until it begins to glow, it is converted into a brown oxide. Heated at +a continued dull red heat, it turns blue. At a higher temperature, it +is oxidized to molybdic acid, when it glimmers and smokes, and is +converted into crystallized molybdic acid upon the surface. + +([chi].) _Protoxide of Molybdenum_ (MoO).--This oxide is a black +powder. + +([chi].) _Deutoxide of Molybdenum_ (MoO^{2}).--This oxide is a dark +copper-colored crystalline powder. + +_Reactions before the Blowpipe._--Metallic molybdenum, its protoxide +and binoxide, are converted in the oxidation flame into molybdic acid. +This acid fuses in the flame of oxidation to a brown liquid, which +spreads, volatilizes, and sublimes upon the charcoal as a yellow +powder, which appears crystalline in the vicinity of the assay. This +sublimate becomes white after cooling. Beyond this sublimate there is +visible a thin and not volatile ore of binoxide, after cooling; this +is of a dark copper-red color, and presenting a metallic lustre. + +Heated in a glass tube, closed at one end, it melts to a brown mass, +vaporizes and sublimates to a white powder upon a cool portion of the +tube. Immediately above the assay, yellow crystals are visible; these +crystals are colorless after cooling, and the fused mass becomes light +yellow-colored and crystalline. + +Upon platinum foil, in the flame of oxidation, it melts and vaporizes, +and becomes light yellow and crystalline after cooling. In the +reduction flame it becomes blue, and brown-colored if the heat is +increased. + +Upon charcoal, in the reduction flame, it is absorbed by the charcoal; +and, with an increase of the temperature, it is reduced to the metal, +which remains as a grey powder after washing off the particles of +charcoal. + +_Borax_ dissolves it, in the oxidation flame, upon platinum wire +easily, and in great quantity, to a clear yellow, which becomes +colorless while cooling. By the addition of more of the molybdenic +acid the bead is dark yellow, or red while hot, and opalescent when +cold. In the reduction flame, the color of the bead is changed to +brown and transparent. By the addition of more of the acid, it becomes +opaque. + +_Microcosmic Salt_ dissolves it in the oxidation flame, upon platinum +wire, to a clear, yellowish-green bead, which becomes colorless after +cooling. In the reduction flame the bead is very dark and opaque, but +becomes of a bright green after cooling. This is the case likewise +upon charcoal. + +_Carbonate of Soda_ dissolves it upon platinum wire in the oxidation +flame with intumescence, to a clear bead, which appears milk-white +after cooling. Upon charcoal the soda and the molybdic acid are +absorbed, the latter is reduced to the metallic state, the metal +remaining as a grey powder after washing off the particles of +charcoal. When molybdic acid, or any other oxide of this metal, is +exposed upon platinum wire, or with platinum tongs, to the point of +the blue flame, a yellowish-green color is communicated to the +external flame. If also any of the compounds of molybdenum are mixed +in the form of a powder with concentrated sulphuric acid and alcohol, +and the latter inflamed, the flame of the alcohol appears colored +green. + +(_c._) _Osmium_ (Os).--This metal occurs associated with platinum. It +is of a bluish-grey color, and is very brittle. Ignited in the open +air, it is oxidized to volatile osmic acid, which is possessed of a +pungent smell, and affects the eyes. It communicates a bright white +color to the flame of alcohol. Osmium oxide (OsO^{2}) is converted in +the oxidation flame to osmic acid, which is volatilized with a +peculiar smell, leaving a sublimate. + +In the reduction flame it is reduced to a dark-brown infusible +metallic powder. It produces no reactions with fluxes. Carbonate of +soda reduces it upon charcoal to an infusible metallic powder, which +appears, after washing off the particles of charcoal, of a dark-brown +color. + + +ELEVENTH GROUP.--PLATINUM, PALLADIUM, IRIDIUM, RHODIUM, RUTHENIUM. + +These metals are infusible before the blowpipe. They are not volatile, +nor are they oxidizable. Their oxides are, in both flames, reduced to +a metallic and infusible powder. They give no reactions with fluxes, +but are separated in the metallic form. These metals are generally +found associated together in the native platinum, also with traces of +copper, lead, and iron. + +The metal palladium is found native, associated with iridium and +platinum. This metal generally occurs in greatest quantity in Brazil. + +The metal rhodium is found along with platinum, but in very small +quantities. + +Iridium occurs in nature associated with osmium, gold, and platinum, +in the mines of Russia. Its great hardness has rendered it desirable +for the points of gold pens. In South America this metal is found +native, associated with platinum and osmium. The latter metal, +associated with platinum and iridium, has been found in South America. + +As these metals will not oxidize or dissolve, they cannot be separated +from each other by the blowpipe with the reagents peculiar to that +species of analysis. It is true that colors may be discerned in the +beads, but these tints proceed from the presence of small traces of +copper, iron, etc. + +The ore of osmium and iridium can be decomposed, and the former +recognized by its fetid odor. This metal, strongly ignited in a glass +tube with nitrate of potash, is converted to the oxide of osmium, +which gives an odor not unlike the chloride of sulphur. + +As the metals of this group are very rare ones, especially the last +four ones, we shall not devote an especial division to each of them. +For a more detailed statement of their reactions, the student is +referred to the large works upon blowpipe analysis. + + +CLASS III. + + +NON-METALLIC SUBSTANCES. + +1. _Water_--2. _Nitric Acid_--3. _Carbon_--4. _Phosphorus_ +--5. _Sulphur_--6. _Boron_--7. _Silicon_--8. _Chlorine_ +--9. _Bromine_--10. _Iodine_--11. _Fluorine_--12. _Cyanogen_ +--13. _Selenium_. + + +(1.) _Water_ (HO).--Pure distilled water is composed of one volume of +oxygen, and two volumes of hydrogen gases; or, by weight, of one part +of hydrogen to eight parts of oxygen gases. Water is never found pure +in nature, but possessing great solvent properties, it always is found +with variable proportions of those substances it is most liable to +meet with, dissolved in it. Thus it derives various designations +depending upon the nature of the substance it may hold in solution, as +lime-water, etc. + +In taking cognizance of water in relation to blowpipe analysis, we +regard it only as existing in minerals. The examination for water is +generally performed thus: the substance may be placed in a dry tube, +and then submitted to heat over a spirit-lamp. If the water exists in +the mineral mechanically it will soon be driven off, but if it exists +chemically combined, the heat will fail to drive it off, or if it +does, it will only partially effect it. The water will condense upon +the cool portions of the tube, where it can be readily discerned. If +the water exists chemically combined, a much stronger heat must be +applied in order to separate it. + +Many substances may be perhaps mistaken for water by the beginner, +such as the volatile acids, etc. + + +(2.) _Nitric Acid_ (NO^{5}).--Nitric acid occurs in nature in potash +and soda saltpetre. These salts are generally impure, containing lime, +as the sulphate, carbonate and nitrate, and also iron in small +quantity. The soda saltpetre generally contains a quantity of the +chloride of sodium. The salts containing nitric acid deflagrate when +heated on charcoal. Substances containing nitric acid may be heated in +a glass tube closed at one end, by which the characteristic red fumes +of nitrous acid are eliminated. If the acid be in too minute a +quantity to be thus distinguished, a portion of the substance may be +intimately mixed with some bisulphate of potash, and treated as above. +The sulphuric acid of the bisulphate combines with the base, and +liberates the nitric acid, while the tube contains the nitrous acid +gas. + +The nitrate of potassa, when heated in a glass tube, fuses to a clear +glass, but gives off no water. When fused on platinum wire, it +communicates to the external flame the characteristic violet color. +When fused and ignited on charcoal, its surface becomes frothy, +indicating the nitric acid. + + +(3.) _Carbon_ (C).--Carbon is found in nature in the pure crystallized +state as the diamond. It occurs likewise in several allotropic states +as graphite, plumbago, charcoal, anthracite, etc. It exists in large +quantities combined with oxygen as carbonic acid. + +The diamond, although combustible, requires too high a heat for its +combustion to enable us to burn it with the blowpipe. When excluded +from the air, it may be heated to whiteness without undergoing fusion, +but with the free access of air it burns at a temperature of 703° C, +and is converted into carbonic acid. If mixed with nitre, the potassa +retains the carbonic acid, and the carbon may be thus easily +estimated. If a mineral containing carbonic acid is heated, the gas +escapes with effervescence, or a strong mineral acid as the +hydrochloric will expel the acid with the characteristic +effervescence. + + +(4.) _Phosphorus, Phosphoric Acid _(PO^{6}).--This acid occurs in a +variety of minerals, associated with yttria, copper, uranium, iron, +lead, manganese, etc. Phosphoric acid may be detected in minerals by +pursuing the following process: dip a small piece of the mineral in +sulphuric acid, and place it in the platinum tongs: this is heated at +the point of the blue flame, when the outer flame will become colored +of a greenish-blue hue. This color will not be mistaken for those of +boracic acid, copper, or baryta. Some of the phosphoric minerals, when +heated in the inner flame, will color the outer flame green. + +If alumina be present with the phosphoric acid, the following wet +method should be adopted for the detection of the latter: the +substance should be powdered in the agate mortar with a mixture of six +parts of soda, and one and a half parts of silica. The entire mass +should now be placed on charcoal, and melted in the flame of +oxidation. The residue should be treated with boiling water, which +dissolves the phosphate and the excess of carbonate of soda, while the +silicate of alumina, with some of the soda, is left. The clear liquor +is now treated with acetic acid, and heated over the spirit-lamp, and +a small portion of crystallized nitrate of silver added; a +lemon-yellow precipitate of phosphate of silver is quickly developed. +Previous to the addition of the nitrate, the liquor should be well +heated; otherwise, a white precipitate of dipyrophosphate of silver +will be produced. + +If the examination be of any of the metallic phosphides, the +substances should be powdered in the agate mortar, and fused with +nitrate of potassa on the platinum wire; the fused mass should be +treated with soda in the same manner as any substance containing +phosphoric acid. The metal and the phosphorus are oxidized, while the +phosphate of potassa is fused, and the metallic oxide separates. + + +(5.) _Sulphur_ (S).--Sulphur is found native in crystals It is +frequently found associated with lime, iron, silica, carbon, etc., and +combined extensively with metals. + +The principal acid of sulphur (the sulphuric, SO^{3}) occurs combined +with the earths, the alkalies, and the metallic oxides. Native sulphur +is recognized, when heated upon charcoal, by its odor (sulphurous +acid) and the blue color of its flame. The compounds of sulphur may be +detected by several methods. If the substance is heated in a glass +tube, closed at one end, the yellow sublimate of sulphur will subside +upon the cool portions of the tube; if the substance should also +contain arsenic, the sublimate will present itself as a light brown +incrustation, consisting of the sulphide of arsenic. + +If the assay is heated in the open glass tube, sulphurous acid will +thus be generated; but, if the gas is too little to be detected by the +smell, a strip of moistened litmus paper will indicate the presence of +the acid. + +The assay will give off sulphurous fumes if heated in the flame of +oxidation. + +If the powdered substance is fused with two parts of soda, and one +part of borax, upon charcoal, the sulphide of sodium is formed. This +salt, if moistened and applied to a polished silver surface, will +blacken it. The borax serves no other purpose than to prevent the +absorption of the formed sulphide of sodium by the charcoal. As +selenium will blacken silver in the manner above indicated, the +presence of this substance should be first ascertained, by heating the +assay; when, if it be present, the characteristic horse-radish odor +will reveal the fact. + +Sulphuric acid may be detected by fusing the substance with two parts +of soda, and one part of borax, on charcoal, in the flame of +reduction; the mass must now be wetted with water, and placed in +contact with a surface of bright silver; when, if sulphuric acid be +present, the silver will become blackened. + +Or the substance may be fused with silicate of soda in the flame of +reduction. In this case, the soda combines with a portion of the +sulphuric acid, which is then reduced to the sulphide, while the bead +becomes of an orange or red color, depending upon the amount of the +sulphuric acid present. If the assay should, however, be colored, then +the previous treatment should be resorted to. + + +(6.) _Boron, Boracic Acid_ (BO^{3}).--This acid occurs in nature in +several minerals combined with various bases, such as magnesia, lime, +soda, alumina, etc. Combined with water, this acid exists in nature as +the native boracic acid; this acid gives with test paper prepared from +Brazil wood, when moistened with water, a characteristic reaction, for +the paper becomes completely bleached. An alcohol solution turns +curcuma test paper brown. Heated on charcoal, it fuses to a clear +bead; but, if the sulphate of lime be present, the bead becomes opaque +upon cooling. + +The following reaction is a certain one: the substance is pulverized +and mixed with a flux of four and a half parts of bisulphate of +potassa, and one part of pulverized fluoride of calcium. The whole is +made into a paste with water, and the assay is placed on the platinum +wire, and submitted to the point of the blue flame. While the assay is +melting, fluoboric gas is disengaged, which tinges the outer flame +green. If but a small portion of boracic acid is present, the color +will be quite evanescent. + + +(7.) _Silica, Silicic Acid_ (SiO^{3}).--This acid exists in the +greatest plenty, forming no inconsiderable portion of the solid part +of this earth. It exists nearly pure in crystallized quartz, +chalcedony, cornelian, flint, etc., the coloring ingredients of these +minerals being generally iron or manganese. + +With _microcosmic salt_, silica forms a bead in the flame of oxidation +which, while hot, is clear, while the separated silica floats in it. A +platinum wire is generally used for the purpose, the end of it being +first dipped in the salt which is fused into a bead, after which the +silica must be added, and then the bead submitted to the flame of +oxidation. + +The silicates dissolve in soda but partially, and then with +effervescence. If the oxygen of the acid be twice that of the base, a +clear bead will be obtained that will retain its transparency when +cold. If the soda be added in small quantity, the bead will then be +opaque. In the first instance, a part of the base which separates is +re-dissolved, and, therefore, the transparency of the glass; but, if +too large a quantity of the soda is added, the separation of the base +is sufficient to render the assay infusible. + + +(8.) _Chlorine_ (Cl).--Chlorine exists in nature always in +combination, as the chlorides of sodium, potassium, calcium, ammonium, +magnesia, silver, mercury, lead, copper, etc. + +The chlorine existing in metallic chlorides may be detected as +follows: the wet way may be accomplished in the following manner. If +the substance is insoluble, it must be melted with soda to render it +soluble; if it be already soluble it must be dissolved in pure water, +and nitrate of silver added, when the one ten-thousandth part of +chlorine will manifest its presence by imparting a milky hue to the +fluid. + +By the blowpipe, chlorine may be detected in the following manner: +Oxide of copper is dissolved in microcosmic salt on the platinum wire +in the flame of oxidation, and a clear bead is obtained. The substance +containing the chlorine is now added, and heat is applied. The assay +will soon be enveloped by a blue or purplish flame. As none of the +acids that occur in the mineral kingdom give this reaction, chlorine +cannot be confounded with them, for those which impart a color to the +flame, when mixed with a copper salt, will not do so when tested in +the microcosmic salt bead as above indicated. + +If the assay is soluble in water, the following method may be +followed: a small quantity of sulphate of copper or iron is dissolved; +a few drops of the solution is placed upon a bright surface of silver, +and the metallic chloride added; when, if chlorine is present, the +silver is blackened. If the chloride is insoluble in water, it must be +rendered soluble by fusion upon a platinum wire with soda, and then +treated as above.[2] + + [2] Plattner. + + +(9.) _Bromine_ (Br).--The bromide of magnesium and sodium exists in +many salt springs, and it is from these that the bromine of commerce +is obtained. The metallic bromides give the same reactions on silver +with the microcosmic bead and copper salt as the metallic chlorides. +The purplish color which, however, characterizes the chlorides, is +more inclined to greenish with the bromides. If the substance be +placed in a flask or glass tube, and fused with bisulphate of potassa, +over the spirit-lamp, sulphurous gas and bromine will be eliminated. +Bromine will be readily detected by its yellow color and its smell. +Bromine may be readily detected by passing a current of chlorine +through the fluid, after which ether is added and the whole is +agitated. The ether rises to the top, carrying with it the bromine in +solution; after being withdrawn, this ether is mixed with potassa, by +which the bromide and bromate of potassa are formed. The solution is +evaporated to dryness, the residue is fused in a platinum vessel, the +bromate is decomposed, while the bromide remains; this must be +distilled with sulphuric acid and the binoxide of manganese. A red or +brown vapor will then appear, indicating the presence of bromine; this +vapor will color starch paste--which may be put in the receiver on +purpose--of a deep orange color. + +If, to a solution containing a bromide, concentrated sulphuric or +nitric acid be added, the bromine is liberated and colors the solution +yellow or red. The hypochlorites act in the same manner. The bromine +salts are coming into use extensively in photography, in consequence +of their greater sensitiveness to the action of light than the +chlorides alone. + + +(10.) _Iodine_ (I).--This element occurs in salt-springs, generally +combined with sodium; it also exists in rock-salt; it has likewise +been found in sea-water, also in a mineral from Mexico, in combination +with silver, and in one from Silesia, in combination with zinc. As +sea-water contains iodine, we would consequently expect to find it +existing in the sea-weeds, and it is generally from the ashes of these +that it is obtained in commerce. + +When the metallic iodides are fused with the microcosmic salt and +copper, as previously indicated, they impart a green color to the +flame. This color cannot be mistaken for the color imparted to the +flame by copper alone. When the metallic iodides are fused in a glass +tube, closed at one end, with the bisulphate of potassa, the vapor of +iodine is liberated, and may be recognized by its characteristic +color. Those mineral waters containing iodine can be treated the same +as for bromine, as previously indicated, while the violet-colored +vapor of the iodine can be easily discerned. The nitrate of silver is +the best test for iodine, the yellow color of the iodide of silver +being not easily mistaken, while its almost insolubility in ammonia +will confirm its identity. The chloride of silver, on the contrary, +dissolves in ammonia with the greatest facility. + +The reactions of iodine are similar to those of bromine with +concentrated sulphuric acid and binoxide of manganese, and with nitric +acid: The iodine is released and, if the quantity be not too great, +colors the liquid brown. If there be a considerable quantity of iodine +present, it is precipitated as a dark colored powder. Either of these, +when heated, gives out the violet-color of the iodine. + +With starch paste free iodine combines, producing a deep blue +compound. If, however, the iodine be in very minute quantity, the +color, instead of being blue, will be light violet or rose color. + +If to a solution of the sulphate of copper, to which a small portion +of sulphurous acid has been added, a liquid containing iodine and +bromine is poured in, a dirty, white precipitate of the subiodide of +copper is produced, and the bromine remains in the solution. The +latter may then be tested for the bromine by strong sulphuric acid. + + +(11.) _Fluorine_ (Fl).--This element exists combined with sodium, +calcium, lithium, aluminium, magnesium, yttrium, and cerium. Fluorine +also exists in the enamel of the teeth, and in the bones of some +animals. This element has a strong affinity for hydrogen, and, +therefore, we find it frequently in the form of hydrofluoric acid. +Brazil-wood paper is the most delicate test for hydrofluoric acid, +which it tinges of a light yellow color. Phosphoric acid likewise +colors Brazil paper yellow, but as this acid is not volatile at a heat +sufficient to examine hydrofluoric acid, there can be no mistake. If +the substance is supposed to contain this acid, it should be placed on +a slip of glass, and moistened with hydrochloric acid, when the test +paper may be applied, and the characteristic yellow color will +indicate the presence of the fluorine. + +As hydrofluoric acid acts upon glass, this property may be used for +its detection. The substance may be put into a glass tube, and +sulphuric acid poured upon it in sufficient quantity to moisten it; a +slight heat applied to the tube will develop the acid, which will act +upon the glass of the tube. If the acid is retained in the mineral by +a feeble affinity, and water be present, a piece of it may be put in +the tube and heated, when the acid gas will be eliminated. The test +paper will indicate its presence, even before it has time to act upon +the glass. If the temperature be too high, fluosilicic acid is +generated, and will form a silicious incrustation upon the cool +portion of the tube. + +If the fluorine is too minute to produce either of the above +reactions, then the following process, recommended by Plattner, should +be followed: the assay should be mixed with metaphosphate of soda, +formed by heating the microcosmic salt to dull redness. The mass must +then be placed in an open glass tube, in such a position that there +will be an access of hot air from the flame. Thus aqueous hydrofluoric +acid is formed, which can be recognized by its smell being more +suffocating than chlorine, and also by the etching produced by the +condensation of vapor in the tube. Moist Brazil paper, applied to the +extremity of the tube, will be instantly colored yellow. + +Merlet's method for the detection of this acid is the following:[3] +Pulverize the substance for examination, then triturate it to an +impalpable powder, and mix it with an equal part of bisulphate of +potassa. Heat the mass gradually in a moderately wide test-tube. The +judicious application of heat must be strictly observed, for if the +operator first heats the part of the tube where the assay rests, the +whole may be lost on account of the glass being shattered. The +spirit-flame must be first applied to the fore part of the tube, and +then made to recede slowly until it fuses the assay. After the mixture +has been for some time kept in a molten state, the lamp must be +withdrawn, and the part containing the assay severed with a file. The +fore part of the tube must then be well washed, and afterwards dried +with bibulous paper. Should the fluorine contained in the substance be +appreciable, the glass tube, when held up to the light, will be found +to have lost its transparency, and to be very rough to the touch. + + [3] Quoted by Plattner. + +Great care should be observed not to allow this very corrosive acid to +come into contact with the skin, as an ulcer will be the consequence +that will be extremely difficult to heal. + +When hydrofluoric acid comes in contact with any silicious substance, +hydrofluosilicic acid gas is always formed. + + +(12.) _Selenium_ (Se).--This element occurs in combination with lead +as the selenide, and with copper as the selenide of copper. It exists +also combined with cobalt and lead, as the selenide of these metals; +also as the selenide of lead and mercury. + +The smallest trace of selenium may be detected by igniting a small +piece of charcoal in the flame of oxidation, when the peculiar and +unmistakable odor of decayed horse-radish will indicate the presence +of that element. An orange vapor is eliminated if the selenium be +present in any quantity, while there is an incrustation around the +assay of a grey color, with a metallic lustre. This incrustation +frequently presents a reddish-violet color at its exterior edges, +often running into a deep blue. If a substance containing selenium be +placed in a glass tube, closed at one end, and submitted to heat, the +selenium is sublimed, with an orange-colored vapor, and with the +characteristic odor of that substance. Upon the cool portions of the +tube a steel-grey sublimate is deposited, and, beyond that, can be +discerned small crystals of selenic acid. If the mineral be the +seleniferous lead glance, sulphurous acid gas will be given off, and +may be detected by the smell, or by a strip of moistened litmus paper. + +If arsenic is present, heating upon charcoal will quickly lead to the +determination of the one from the other. + + * * * * * + + + + +TABULAR STATEMENT OF THE REACTIONS OF MINERALS BEFORE THE BLOWPIPE. + + +In PART THIRD of this work, commencing at page 109, the student will +find a sufficiently explicit description of the blowpipe reactions of +those principal substances that would be likely to come beneath his +attention. The following tabular statement of those reactions--which +we take from Scheerer and Blanford's excellent little work upon the +blowpipe--will be of great benefit, as a vehicle for consultation, +when the want of time--or during the hurry of an examination--precludes +the attentive perusal of the more lengthy descriptions in the text. + +In the examination of minerals, before the student avails himself of +the aid of the blowpipe, he should not neglect to examine the specimen +rigidly in relation to its physical characters, such as its hardness, +lustre, color, and peculiar crystallization. It is where the +difference of two minerals cannot be distinguished by their physical +appearance, that the aid of the blowpipe comes in most significantly +as an auxiliary. For instance, the two minerals molybdenite and +graphite resemble each other very closely, when examined in regard to +their physical appearance, but the blowpipe will quickly discriminate +them, for if a small piece of the former mineral be placed in the +flame of oxidation, a bright green color will be communicated to the +flame beyond it, while in the latter there will be no color. Thus, in +a very short time, these two minerals can be distinguished from each +other by aid of the blowpipe, while no amount of physical examination +could determine that point. The blowpipe is equally an indispensable +instrument in the determination of certain minerals which may exist in +others as essential or non-essential constituents of them. For +instance, should a minute quantity of manganese be present in a +mineral, it must be fused with twice its bulk of a mixture of two +parts of carbonate of soda, and one part of the nitrate of potassa, in +the flame of oxidation upon platinum foil. The manganate of soda thus +formed will color the fused mass of a bluish-green tint. + +Or a slight quantity of arsenic may be discerned by the following +process recommended by Plattner:[4] one grain of the finely pulverized +metal is mixed with six grains of citrate of potassa, and slowly +heated on the platinum spoon. By this means the metals are oxidized, +while the arseniate of potassa is obtained. Then boil the fused mass +in a small quantity of water in a porcelain vessel till all tho +arseniate is dissolved. The metallic oxides are allowed to subside, +and the above solution decanted off into another porcelain vessel. A +few drops of sulphuric acid are added, and the solution boiled to +expel the nitric acid, after which it is evaporated to dryness. In +this operation, the sulphuric acid should be added only in sufficient +quantity to drive off the nitric acid, or, at the utmost, to form a +bisulphate with the excess of potassa. When dry, the salt thus +obtained is pulverized in an agate mortar, and mixed with about three +times its volume of oxalate of potassa, and a little charcoal powder. +The mixture is introduced into a glass bulb having a narrow neck, and +gently warmed over a spirit-lamp in order to drive off the moisture, +which must be absorbed by a piece of blotting-paper in the neck of the +bulb. After a short time, the temperature is increased to a low red +heat, at which the arsenious acid is reduced and the metallic arsenic +sublimed, and which re-condenses in the neck of the bulb. If there +the arsenic be so small in quantity as to exhibit no metallic lustre, +the neck of the bulb may be cut off with a file immediately above the +sublimate, and the latter exposed to the flame of the blowpipe, when +the arsenic is volatilized, and may be recognized by its garlic odor. + + [4] Quoted by Scheerer. + +If the presence of cadmium is suspected in zinc-blende, it may be +detected by fusing a small piece of the blende upon charcoal in +carbonate of soda. The peculiar bright yellow sublimate of the oxide +of cadmium, if it be present, will not fail to indicate it. This +incrustation can be easily distinguished from that of zinc. Thus, with +the three illustrations we have given, the student will readily +comprehend the great utility of the blowpipe in the examination of +minerals. + +Although the following tables were not arranged especially for the +last part of this work, still this arrangement is so good that by +their consultation the student will readily comprehend at a glance +what requires some detail to explain, and we feel no hesitation in +saying that, although they are not very copious, they will not fail to +impart a vast amount of information, if consulted with any degree of +carefulness. + +The minerals given are such as are best known to English and American +mineralogists under the names specified. For more detailed reactions +than could be crowded into a table, the student will have to consult +the particular substance as treated in Part Third. If this part is +perused carefully previous to consulting the tables, these will be +found eminently serviceable as a refresher of the memory, and may thus +save much time and trouble. + +And, finally, we would certainly recommend the student, after he shall +have gone through our little volume (if he is ambitious of making +himself a thorough blowpipe analyst), to then take up the larger works +of Berzelius and Plattner, for our treatise pretends to nothing more +than a humble introduction to these more copious and scientific works. + + * * * * * + +Mineral. Diamond + +Formula. C + +Behavior + + in glass-bulb. -- + + on platinum foil. In fine powder is slowly consumed without + residue in a strong oxidizing Flame. + + * * * * * + +Mineral. Graphite + +Formula. C with some iron silica, etc. + +Behavior + + in glass-bulb. Generally gives off water. + + on platinum foil. Is slowly consumed leaving more or less ash, + principally Fe^{2}O^{3}. + + * * * * * + +Mineral. Anthracite + +Formula. C + x[.H] + +Behavior + + in glass-bulb. Evolves water. + + on platinum foil. Is slowly consumed with the exception of a small + quantity of ash. + + + * * * * * + +Mineral. Wallsend-coal + +Formula. C, H, O, S and ash. + +Behavior + + in glass-bulb. Intumesces and gives off water and tarry matters + which partly condense in bulb, and leave a + porous coke. + + on platinum foil. Takes fire under blowpipe flame, and burns with + a smoky flame, depositing much soot and leaving + a porous cinder which burns slowly and leaves a + small ash. + + * * * * * + +Mineral. Cannel-coal + +Formula. C, H, N, O, S and ash. + +Behavior + + in glass-bulb. As the preceding but gives off more tar. + + on platinum foil. Similar to the preceding. If held to the + lamp-flame, takes fire and burns for some + seconds. + + * * * * * + + +Mineral. Brown-coal + +Formula. C, H, N, O, S, and ash. + +Behavior + + in glass-bulb. Gives off much water and tar, and leaves a + porous cinder retaining the form of the original + fragment. + + on platinum foil. Burns slowly and without flame, leaving some + ash. + + * * * * * + +Mineral. Asphaltum + +Formula. C + H + O. + +Behavior + + in glass-bulb. Fuses with ease affording an empyreumatic oil + having an alkaline reaction, and combustible + gasses, and leaves a carbonaceous residue, + which is entirely consumed under the blowpipe + flame, except a little ash. + + on platinum foil. Takes fire and burns with a bright flame and a + thick smoke. + + * * * * * + +Mineral. Elaterite + +Formula. C + H. + +Behavior + + in glass-bulb. Fuses and gives off water having an acid + reaction, naphtha and a tarry fluid, which + chiefly condense in the neck of the bulb, and + leave a light, pulverulent carbonaceous residue. + + on platinum foil. Fuses, takes fire, and burns with a smoky flame, + leaving a carbonaceous residue, which under the + blowpipe flame, is quickly consumed, with the + exception of the ashes. + + * * * * * + +Mineral. Hachettine + +Formula. C + H. + +Behavior + + in glass-bulb. Fuses to a clear colorless liquid, which + solidifies on cooling and has a tallow-like + smell. + + on platinum foil. Fuses, takes fire, and burns with a bright flame + until entirely consumed. + + * * * * * + +Mineral. Ozokerite + +Formula. C + H. + +Behavior + + in glass-bulb. Fuses readily to a clear brown oily fluid, which + solidifies on cooling. + + on platinum foil. As the preceding. + + * * * * * + +Mineral. Amber + +Formula. C + H + O. + +Behavior + + in glass-bulb. Fuses with difficulty, and affords water, an + empyreumatic oil, and succinic acid which + condense in the neck of the bulb leaving a + shining black residue. + + on platinum foil. Takes fire and burns with a yellow flame and a + peculiar aromatic odor. + + * * * * * + +Mineral. Mellite + +Formula. [...Al][=M]^{3} + 15[.H] + +Behavior + + in glass-bulb. Gives off water. If heated to redness, is + carbonized, and gives a slight empyreumatic odor. + + on platinum foil. On charcoal burns to a white ash, which moistened + with nitrate of cobalt and heated shows the + alumina reaction. + + * * * * * + + POTASH. + + * * * * * + +Mineral. Nitre + +Formula. [.K][.....N] + +Behavior + + (1) in glass-bulb. Fuses readily to a clear liquid and with a + strong heat boils with the evolution of oxygen. + + (2) in open tube. -- + + (3) on charcoal. Deflagrates leaving a saline mass, which is + absorbed into charcoal and gives a sulphur + reaction on silver. + + (4) in forceps. On platinum wire fuses and colors the flame + violet more or less modified by lime and soda. + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. -- + + (8) Special reactions. With bisulphate of potassa in the glass-bulb + evolves nitrous fumes. + + * * * * * + +Mineral. Polyhalite + +Formula. [.K][...S]+[.Mg][...S]+2[.Ca][...S]+2[.H] + +Behavior + + (1) in glass-bulb. Gives off water. + + (2) in open tube. -- + + (3) on charcoal. Fuses to a reddish bead, which in the reducing + flame solidifies and shrinks to a hollow crust. + + (4) in forceps. On platinum wire fuses and colors the flame + yellow from a small quantity of soda. + + (5) in borax. Dissolves with ebullition to a clear glass, + which is slightly colored by iron, and when + saturated become opaque on cooling. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Fuses. The alkalies are absorbed by the charcoal + leaving the lime and magnesia infusible on the + surface. + + (8) Special reactions. The alkaline mass when laid on silver gives a + sulphur reaction. + + * * * * * + + SODA. + + * * * * * + + +Mineral. Rock-salt + +Formula. NaCl. + +Behavior + + (1) in glass-bulb. Fuses to a clear liquid + + (2) in open tube. -- + + (3) on charcoal. Fuses, is absorbed by the charcoal and partially + volatilized incrusting the charcoal around. + + (4) in forceps. Fuses with great ease and colors the flame + yellow. + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. -- + + (8) Special reactions. Gives the chlorine reactions. + + * * * * * + +Mineral. Natron + +Formula. [.Na][..C] + 10[.H] + +Behavior + + (1) in glass-bulb. Fuses, with the evolution of water. + + (2) in open tube. -- + + (3) on charcoal. Fuses, and is absorbed into the pores of the + charcoal. + + (4) in forceps. Fuses and behaves as the preceding. + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. -- + + (8) Special reactions. Dissolves in acid with violent effervescence. + + * * * * * + +Mineral. Soda-nitre + +Formula. [.Na][.....N]. + +Behavior + + (1) in glass-bulb. Fuses and if strongly heated evolves nitrous + fumes. + (2) in open tube. + -- + (3) on charcoal. + Deflagrates and is absorbed into the charcoal. + + (4) in forceps. Deflagrates on platinum wire, coloring the flame + yellow. + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. -- + + (8) Special reactions. In a glass-bulb with bisulphate of potassa, + gives the NO^{5}-reaction. + + * * * * * + +Mineral. Glauber-salt + +Formula. [.Na][...S] + 10[.H]. + +Behavior + + (1) in glass-bulb. Fuses and gives off water having a neutral + reaction. + + (2) in open tube. -- + + (3) on charcoal. Fuses, and is absorbed by the charcoal. The + saturated charcoal laid upon silver gives the + sulphur reaction + + (4) in forceps. Fuses and colors the flame yellow. + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. -- + + (8) Special reactions. Gives the SO^{3}-reaction. + + * * * * * + +Mineral. Glauberite + +Formula. [.Na][...S] + [.Ca][...S]. + +Behavior + + (1) in glass-bulb. Decrepitates with the evolution of more or less + water, and when strongly heated fuses to a clear + liquid. + + (2) in open tube. -- + + (3) on charcoal. Fuses to a clear bead, then spreads out; the + soda is absorbed and the lime left on the + surface. Laid on silver, the fused mass gives a + sulphur reaction. + + (4) in forceps. Fuses easily to a clear glass, coloring the + flame yellow. + + (5) in borax. Fuses easily and gives the lime reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As alone in charcoal. + + (8) Special reactions. As in preceding. + + * * * * * + +Mineral. Borax + +Formula. [.Na][...B]^{2}+10[.H]. + +Behavior + + (1) in glass-bulb. Intumesces with the evolution of water, and + under a strong heat fuses. + + (2) in open tube. -- + + (3) on charcoal. Intumesces and fuses to a clear bead more or + less colored by impurities. + + (4) in forceps. As on charcoal. + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. Fuses to a clear bead, which becomes crystalline + on cooling. + + (8) Special reactions. Gives the boracic-acid-reaction. + + * * * * * + +Mineral. Cryolite + +Formula. 3NaFl+Al^{2}Fl^{3}. + +Behavior + + (1) in glass-bulb. Decrepitates slightly and gives a trace of + water. + + (2) in open tube. If heated so that the flame be allowed to play + up the tube upon the mineral, flourine is + evolved, which corrodes the interior of the + tube. + + (3) on charcoal. Fuses to a limpid bead, which on cooling becomes + a white enamel. If heated for some time, it + bubbles, gives off fluorine and becomes + infusible. + + (4) in forceps. Fuses, coloring the flame yellow. + + (5) in borax. Dissolves to a clear bead, which is rendered + opaque by a large addition. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Fuses to a clear bead, then spreads out on the + charcoal, the soda is absorbed, and an infusible + mass of alumina remains. + + (8) Special reactions. If the alumina residue obtained be moistened + with cobalt solution and heated strongly, it + assumes a beautiful blue color. + + * * * * * + + BARYTA AND STRONTIA. + + * * * * * + + +Mineral. Heavy-spar + +Formula. [.Ba][...S]. + +Behavior + + (1) in glass-bulb. Sometimes decrepitates and gives off more or + less water + + (2) in open tube. -- + + (3) on charcoal. Fuses in the reducing flame. + + (4) in forceps. Fuses with difficulty on edges. Colors the outer + flame green. In reducing flame forms BaS, which + fuses readily. + + (5) in borax. Gives the baryta-reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Fuses to a clear bead; then spreads out and is + absorbed into the charcoal. The fused mass laid + on silver gives the S-reaction. + + (8) Special reactions. If fused with potassa on platinum, gives the + SO^{3}-reaction. + + * * * * * + +Mineral. Celestine + +Formula. [.Sr][...S]. + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. -- + + (3) on charcoal. Fuses to a milk-white bead. + + (4) in forceps. Colors the flame crimson. + + (5) in borax. Gives the strontia-reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Similar to the preceding. + + (8) Special reactions. Similar to the preceding. + + * * * * * + +Mineral. Witherite + +Formula. [.Ba][..C]. + +Behavior + + (1) in glass-bulb. Decrepitates more or less and evolves Water. + + (2) in open tube. -- + + (3) on charcoal. Fuses, effervesces, and is partially absorbed by + the charcoal. + + (4) in forceps. Colors the outer flame intensely green. + + (5) in borax. Dissolves with effervescence and gives the + baryta-reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Fuses to a clear bead; then spreads out and + passes into the charcoal. + + (8) Special reactions. In dilute HCl dissolves with much effervescence. + + * * * * * + +Mineral. Strontianite + +Formula. [.Sr][..C]. + +Behavior + + (1) in glass-bulb. Becomes opaque. + + (2) in open tube. -- + + (3) on charcoal. As in the forceps. + + (4) in forceps. Exfoliates and becomes arborescent. The + filaments glow brilliantly and fuse on the + point. Colors the flame brilliantly crimson. + + (5) in borax. Resembles the preceding. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As the preceding. + + (8) Special reactions. As the preceding. + + * * * * * + +Mineral. Barytocalcite. + +Formula. [.Ba][..C] + [.Ca][..C]. + +Behavior + + (1) in glass-bulb. As in the preceding. + + (2) in open tube. -- + + (3) on charcoal. In powder frits together, but does not fuse. + + (4) in forceps. Colors the flame green in the centre and red + towards the point. + + (5) in borax. Dissolves with effervescence. In large + quantities gives a semi-crystalline bead. + + (6) in mic. salt. As in borax, but the saturated bead is + milk-white. + + (7) with carb. soda. Fuses, and is partially absorbed leaving the + lime on the surface. + + (8) Special reactions. As witherite. + + * * * * * + + LIME. + + * * * * * + + +Mineral. Gypsum + +Formula. [.Ca][...S] + 2[.H]. + +Behavior + + (1) in glass-bulb. Turns white, giving off water and being + converted into plaster of Paris. + + (2) in open tube. -- + + (3) on charcoal. In the reducing flame forms CaS, which has an + alkaline reaction on test paper, and gives a + sulphur-reaction when laid on silver and + moistened. + + (4) in forceps. Fuses with difficulty to a bead, coloring the + flame red. + + (5) in borax. Dissolves to a clear bead, which gives the lime- + reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Behaves as lime. The alkaline mass laid on + silver and moistened gives the sulphur-reaction. + + (8) Special reactions. Gives the sulphuric-acid reaction. + + * * * * * + +Mineral. Apatite + { Cl +Formula. [.Ca]{ -- +3[.Ca]^{3}[.....P] + { Fl +Behavior + + (1) in glass-bulb. Occasionally decrepitates and gives off some + water. + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. IV. Previously dipped in SO^{3} colors the flame + green, afterwards red. + + (5) in borax. Dissolves easily and when in some quantity gives + an opaline bead. + + (6) in mic. salt. Gives the lime-reaction. + + (7) with carb. soda. Is infusible. The alkali is absorbed, leaving + the lime on the on the surface of the charcoal. + + (8) Special reactions. With microcosmic salt and oxide of copper, gives + the chlorine-reaction. With microcosmic salt in + the open tube evolves fluorine. + + * * * * * + +Mineral. Pharmacolite + +Formula. [.Ca]^{2}[.....As] + 6[.H]. + +Behavior + + (1) in glass-bulb. Gives off water, and emits an arsenical odor. + + (2) in open tube. -- + + (3) on charcoal. Fuses to an opaque bead and emits a strong smell + of arsenic. + + (4) in forceps. Fuses to a translucent violet colored bead, the + color being due to cobalt. Colors the flame blue + at first, then faintly red. + + (5) in borax. Dissolves readily to a bead strongly colored by + cobalt, which obscures the lime-reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Fuses, and emits As. The alkali is then absorbed + by the charcoal, as in the preceding. + + (8) Special reactions. -- + + * * * * * + +Mineral. Calespar + +Formula. [.Ca][..C]. + +Behavior + + (1) in glass-bulb. Turns white and sometimes decrepitates. Strongly + heated loses CO^{2} and becomes caustic. + + (2) in open tube. -- + + (3) on charcoal. Turns white, or brown if containing much iron or + manganese and glows brilliantly. + + (4) in forceps. Glows brilliantly, coloring the flame red. + Becomes caustic and shows a strong alkaline + reaction. + + (5) in borax. Dissolves with evolution of CO^{2} and when pure + gives the lime-reaction. The bead is generally + more or less colored by iron and manganese. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Fuses, and behaves as other lime-salts. + + (8) Special reactions. Dissolves with effervescence in cold HCl. + + * * * * * + +Mineral. Fluorspar + +Formula. CaFl + +Behavior + + (1) in glass-bulb. Phosphoresces with various colors, when heated + in the dark. + + (2) in open tube. -- + + (3) on charcoal. Fuses easily to a clear bead, which becomes opaque + on cooling, then loses fluorine, glows brilliantly + and becomes infusible. + + (4) in forceps. As on charcoal. Colors the flame red. + + (5) in borax. Gives the lime-reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Fuses to a clear bead, opaque on cooling. With + an addition of the alkali behaves as lime. + + (8) Special reactions. With microcosmic salt in open tube gives the + fluorine-reaction. + + * * * * * + + MAGNESIA. + + * * * * * + +Mineral. Brucite + +Formula. [.Mg][.H]. + +Behavior + + (1) in glass-bulb. Evolves water. + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. V. + + (5) in borax. Behaves as magnesia. Sometimes gives a faint + iron-reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Behaves as magnesia. + + (8) Special reactions. With nitrate of cobalt, gives the magnesia + reaction + + * * * * * + +Mineral. Epsomite + +Formula. [.Mg][...S] + 7[.H]. + +Behavior + + (1) in glass-bulb. Evolves water having an acid reaction on test + paper. + + (2) in open tube. -- + + (3) on charcoal. Gives of HO and SO^{3}, shines brilliantly, and + becomes alkaline and caustic. + + (4) in forceps. V. As on charcoal. + + (5) in borax. Behaves as magnesia. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. The alkali is absorbed leaving the magnesia + on surface of the charcoal. Gives the + sulphur-reaction on silver. + + (8) Special reactions. The magnesian residue obtained on treating with + carbonate of soda (7), assumes a flesh-tint, + when treated with cobalt. + + * * * * * + +Mineral. Boracite + +Formula. [.Mg][...B]^{2} + 2[.Mg][...B]. + +Behavior + + (1) in glass-bulb. Occasionally gives off a trace of water. + + (2) in open tube. -- + + (3) on charcoal. Fuses with intumescence to a white crystalline + bead. + + (4) in forceps. I. As on charcoal. Colors the flame green. + + (5) in borax. Fuses easily to a clear bead, which is + crystalline, when containing much of the + mineral, and is usually slightly tinted by + iron. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. With a small quantity of alkali fuses to a clear + bead on cooling. With a larger quantity gives a + clear, uncrystallizable bead. + + (8) Special reactions. -- + + * * * * * + +Mineral. Magnesite + +Formula. [.Mg][..C]. + +Behavior + + (1) in glass-bulb. Sometimes gives off a small quantity of water. + + (2) in open tube. -- + + (3) on charcoal. Is infusible. With cobalt-solution, assumes a + dusky flesh tint. + + (4) in forceps. -- + + (5) in borax. Behaves as magnesia. Sometimes a slight + iron-reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Fuses to a bead, the soda is then absorbed, + leaving an infusable mass of magnesia. + + (8) Special reactions. The magnesian residue obtained by fusing with + carbonate of soda gives the magnesian-reaction + with nitrate of cobalt. Dissolves with + effervescence in warm HCl. + + * * * * * + +Mineral. Mesitine spar + +Formula. ([.Mg][.Fe][.Mn])[..C]. + +Behavior + + (1) in glass-bulb. As magnesite. + + (2) in open tube. -- + + (3) on charcoal. Is infusible. Assumes a deep brown color. + + (4) in forceps. V. + + (5) in borax. Gives the iron and manganese-reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As magnesite, but the residual mass has a dark + color from iron and manganese. + + (8) Special reactions. Dissolves with effervescense in warm HCl. With + carbonate of soda and nitre gives a + manganese-reaction. + + * * * * * + + ALUMINA. + + * * * * * + +Mineral. Sapphire + Corundum + Emery + +Formula. [...Al=]. + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. -- + + (3) on charcoal. -- + + + (4) in forceps. V. + + (5) in borax. In fine powder dissolves slowly to a colorless + glass. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. -- + + (8) Special reactions. In fine powder moistened with cobalt-solution + and heated yields a blue color. + + * * * * * + +Mineral. Websterite + +Formula. [...Al][...S] + 9[.H]. + +Behavior + + (1) in glass-bulb. Gives off water, and, when heated to incipient + redness, sulphurous acid. + + (2) in open tube. -- + + (3) on charcoal. Gives off water and SO^{3}, leaving an infusible + mass. + + (4) in forceps. V. + + (5) in borax. Behaves as alumina. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Yields an infusible mass, which laid on silver + and moistened, produces a black stain. + + (8) Special reactions. Fused with potassa in platinum has no action on + silver. Cobalt-solution produces the alumina + reaction. + + * * * * * + +Mineral. Native Alum + +Formula. [.R][...S] + [...Al][...S]^{3} + 24[.H]. + +Behavior + + (1) in glass-bulb. Intumesces greatly and gives off much water. + Strongly heated, evolves SO^{3}, which reddens + litmus. + + (2) in open tube. -- + + (3) on charcoal. Intumesces and become infusible. + + (4) in forceps. V. Colors the flame violet if a potassa + alum--yellow if soda--be present. + + + (5) in borax. Dissolves and gives the iron and manganese + reaction, if these oxides be present. Otherwise + the bead is colorless. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. The alkali is absorbed into the charcoal, + leaving an infusable mass which gives the sulfur + reaction on silver. + + (8) Special reactions. If not containing too much iron or manganese + gives an alumina reaction with nitrate of of + cobalt. In other respects as the preceding. + + * * * * * + +Mineral. Turquoise + +Formula. [...Al=]^{2}[.....P] + 5[.H]. + +Behavior + + (1) in glass-bulb. Evolves water, occasionally decrepitates and + turns black. + + (2) in open tube. -- + + (3) on charcoal. Turns brown, but remains infusible. + + (4) in forceps. V. As on charcoal. Colors the outer flame green. + + (5) in borax. In the oxidizing flame, gives a green bead, due + to copper and iron. In reducing flame, opaque red. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Intumesces, then fuses to a semi-clear glass + colored by iron. With more alkali yields an + infusible mass. + + (8) Special reactions. Gives the phosphoric-acid reaction. + + * * * * * + +Mineral. Wavellite + +Formula. [Al=]F^{3} + 3([...Al=]^{4}[.....P]^{3} + 18[.H].) + +Behavior + + + (1) in glass-bulb. Evolves water and some fluorine, which attacks + the glass. + + (2) in open tube. -- + + (3) on charcoal. Exfoliates and turns white. + + (4) in forceps. V. As on charcoal. Colors the outer flame green, + especially if moistened with SO^{3}. + + (5) in borax. As alumina. Generally gives also a slight iron + reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Forms an infusible white mass. + + (8) Special reactions. With cobalt-solution on charcoal gives the + alumina reaction. + + * * * * * + +Mineral. Spinel + +Formula. [.R][...Al=]. + +Behavior + + + (1) in glass-bulb. -- + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. V. + + (5) in borax. Gives a slight iron reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Fuses partially and forms a porous mass. + + (8) Special reactions. With nitrate of cobalt gives the alumina + reaction. With nitre and carbonate of soda a + slight manganese reaction. + + * * * * * + + +SILICATES. + + +The presence of silica in a mineral can easily be ascertained by +treating a small fragment in a bead of microcosmic salt. The bases +will dissolve out with more or less difficulty in the salt, and the +silica being insoluble will remain suspended in the bead, retaining +the original form of the fragment. In borax, the silicates of lime and +magnesia generally dissolve with considerable ease, but those of +alumina slowly and with difficulty. The silicates of lime are moreover +frequently characterized by intumescence or ebullition, when heated in +the forceps in the blowpipe flame. The minerals presenting this +character are marked in the table. As the most convenient mode of +classifying the silicates for blowpipe examination, the following +arrangement will be adopted: + + +TABLE I.--ANHYDROUS SILICATES. + +TABLE II.--HYDROUS SILICATES. + +FUSIBILITY. + + I. Readily fusible to a bead. + II. With difficulty fusible to a bead. +III. Readily fusible on the edges. + IV. With difficulty fusible on the edges. + V. Infusible. + + a. Afford a fluid bead with carbonate of soda. + b. Afford a fluid bead with but little of that salt, but with a + larger quantity a slaggy mass. + c. Afford a slaggy mass only. + + +This classification of minerals, according to their fusibility and +their behavior with carbonate of soda, was originally proposed by +_Berzelius_, and a table of the principal oxidized minerals arranged +according to these characters is given in his handbook of the +blowpipe, and thence adopted, with some alterations by _Plattner_, in +the very excellent and detailed work already many times cited. In the +following general table I., the more important silicates only are +included, and in table II. are enumerated in alphabetical order those +which afford characteristic reactions. + + +TABLE I. + + +Anhydrous Silicates. +________________________________________________________________________ +Fus. alone and with NaC. + + Mineral. Formula. +________________________________________________________________________ +I. + a. Axinite ([.Ca][.Mg])^{3}([...B][...Si])^{3} + + ([...Al=][...Fe=][...Mn=])^{2}([...Si][...B]) Int. + Elaolite ([.K][.Na])^{3}[...Si] + 3[...Al=][...Si] Int. + Garnet [.R]^{3}[...Si] + [.R=][...Si] + Oligoclase [.Na][...Si] + [...Al=][...Si]^{2} + Scapolite ([.Ca][.Na])^{3}[...Si]^{2} + 2[...Al=][...Si] Int. + Spodumene ([.Li][.Na])^{3}[...Si]^{2} + 4[...Al=][...Si]^{2}Int. + b. Asbestos As Hornblende + to II. + Augite ([.Ca][.Mg][.Fe][.Mn])^{3}[...Si]^{2} Int. + some var. + Epidote ([.Ca]Fe)^{3}[...Si] + Int. + to III. 2([...Al][...Fe][...Mn])[...Si] + Hornblende ([.Ca][.Mg][.Fe])^{4} + ([...Si][...Al=])^{3} Int. + some var. + Sodalite [.Na]^{3}[...Si] + 3[...Al=][...Si] + NaCl Int. + to III. + Vesuvian 3([.Ca][.Mg])^{3}[...Si] + + 2([...Al=][...Fe=])[...Si] Int. + c. Biaxial Mica [.K][...Si] + 4([...Al=][...Fe=])[...Si] + to III. + Hauyne ([.K][.Na])^{3}[...Si] + 3[...Al=][...Si] + + [.Na][...Si] + Tourmaline ([.R][...R=][...B])^{4}[...Si]^{3} Int. + to V. + +II. + a. Labradorite ([.Ca][.Na][.K])[...Si] + + ([...Al=][...Fe=])[...Si] + Lepidolite (KNaL)F + ([...Al=][...Fe=])[...Si]^{2}? + Ryacolite [.K][...Si] + [...Al=][...Si]^{2} + Albite [.Na][...Si] + [...Al=][...Si]^{3} + b. Augite [.R]^{3}[...Si]^{2} + some var. + Actinolite ([.Ca][.Mg][.Fe])^{4}[...Si]^{3} Int. + Diopside ([.Ca][.Mg])^{3}[...Si]^{2} | + Humboltilite 2([.Ca][.Mg][.Na][.K])[...Si] + + ([...Al=][...Fe=])[...Si] + Sahlite As Augite + Tremolite ([.Ca][.Mg])^{4}[...Si]^{3} + c. Pyrope ([.Ca][.Mg][.Fe])^{3}[...Si] + Al[...Si] + + m[...Cr]? + +III. + a. Anorthite ([.Ca][.Mg][.Na][.K])^{3}[...Si] + + 3([...Al=][...Fe=])[...Si] + Nepheline ([.Na][.K][.Ca])^{2}[...Si] + 2[...Al=][...Si] + Obsidian [...Si],[...Al=],[...Fe=],[.Fe],[.Ca][.Na][.K] Int. + Orthoclase ([.K][.Na])[...Si] + [...Al=][...Si]^{3} + Petalite ([.Li][.Na])^{3}[...Si]^{4} + 4[...Al=][...Si]^{4} + Pumice [...Si],[...Al=],[.Ca],[.K],[.Na],[.H] Int. + b. Gadolinite ([.Y][.Ce][.La][.Fe][.Ca])^{3}[...Si] + to V. + Nephrite ([.Ca][.Mg][.Fe])^{4}[...Si]^{3}? Int. + Wollastonite [.Ca]^{3}[...Si]^{2} | + c. Iolite ([.Mg][.Fe])^{3}[...Si]^{2} + 3[...Al=][...Si] + +IV. + a. Beryl [...Be][...Si]^{2} + [...Al=][...Si]^{2} + b. Diallage ([.Ca][.Mg][.Fe])^{3}([...Si][...Al=])^{2} + Hypersthene ([.Mg][.Fe])^{3}[...Si]^{2} | + c. Fuchsite ([.K]^{5}[...Si])^{2} + + 9([...Al=][...Cr=])^{6}[...Si]^{6} +V. + a. Leucite [.K]^{3}[...Si]^{2} + [...Al=][...Si]^{2} + b. Chondrodite ([.Mg],[.Mg]F)^{4}([...Si]SiF^{3}) + Olivine ([.Mg][.Fe][.Ca])^{2}[...Si] + c. Andalusite ([...Al=]Fe)^{3}[...Si]^{2} + Chrysoberyl [...Be] + [...Al=] + Kaynite [...Al=]^{3}[...Si]^{2} + Pycnite 6[...Al=]^{3}[...Si]^{2} + (3[...Al=]F^{3} + + 2[...Si]F^{3}) + Topaz 6[...Al=]^{3}[...Si]^{2} + (3[...Al=]F^{3} + + 2[...Si]F^{3}) + Zircon [...Zr=][...Si] + Staurolite ([...Al=]Fe)^{2}[...Si] +________________________________________________________________________ + + +Hydrous Silicates. +________________________________________________________________________ +Fus. alone and with NaC. + + Mineral. Formula. +________________________________________________________________________ +I. + a. Analcime [.Na]^{3}[...Si]^{2} + 3[...Al=][...Si]^{2} + + 6[.H] Int. + Apophyllite ([.K], KF)([...Si], SiF^{3}) + 6[.Ca][...Si] + + 15[.H] Int. + Brewsterite ([.Sr][.Ba])[...Si] + [...Al=][...Si]^{3} + 5[.H] Int. + Chabasite ([.Ca],[.Na],[.K])^{3}[...Si] + + 3[...Al=][...Si]^{2} + 18[.H] Int. + Lapis Lazuli [...Si],[...S],[...Al=], Fe, [.Ca], [.Na], [.H] + Laumonite [.Ca]^{3}[...Si]^{2} + 3[...Al=][...Si]^{2} + + 12[.H] Int. + Mesotype ([.Na][.Ca])[...Si] + [...Al=][...Si] + 3[.H] Int. + Natrolite [.Na][...Si] + [...Al=][...Si] + 2[.H] Int. + Prehnite [.Ca]^{2}[...Si] + [...Al=][...Si] + [.H] Int. + Scolezite [.Ca][...Si] + [...Al=][...Si] + 3[.H] Int. + Thomsonite ([.Ca][.Na])^{3}[...Si] + 3[...Al=][...Si] + + 7[.H] Int. + Datholite 2[.Ca]^{3}[...Si] + [...B]^{3}[...Si]^{2} + 3[.H] Int. + Heulandite [.Ca][...Si] + [...Al=][...Si]^{3} + 5[.H] Int. + Stilbite [.Ca][...Si] + [...Al=][...Si]^{3} + 6[.H] Int. + b. Okenite [.Ca]^{3}[...Si]^{4} + 6[.H] Int. + Pectolite ([.Ca][.Na])^{4}[...Si]^{3} + [.H] Int. + c. Saponite 2[.Mg]^{3}[...Si]^{2} + [...Al=][...Si] + + 10 or 6[.H] +II. + a. Antrimolite 3([.Ca][.K])[...Si] + 5[...Al=][...Si] + + 15[.H] + Harmatome [...Ba][...Si] + [...Al=]S^{2} + 5[.H] + b. Brevicite [.Na][...Si] + [...Al=][...Si] + 2[.H] + Orthite [.R]^{3}[...Si] + [...R=][...Si] + ([.H]?) Int. + +III. + c. Pitchstone [...Si],[...Al=], Fe, [.Mg][.Na], [.K][.H] + Talc to V. [.Mg]^{6}[...Si]^{5} + 2[.H] + Chlorite 3([.Mg]Fe)^{3}[...Si] + ([...Al=]Fe)^{2}[...Si] + + 9[.H] + Pinite [...Si],[...Al=],[.Fe],[.K],[.Mg],[.H] + +IV. + a. Steatite [.Mg]^{6}[...Si]^{5} + 4[.H] + c. Gilbertite [...Si],[...Al=],[.Fe],[.Mg],[.H] Int. + Meerschaum [.Mg][...Si] + [.H] | + Serpentine [.Mg]^{9}[...Si]^{4} + 6[.H] | +V. + a. Gismondine ([.Ca][.K])^{2}[...Si] + 2[...Al=][...Si] + 9[.H] +________________________________________________________________________ + + +TABLE II. + +_______________________________________________________________________ + | +Analcime | If transparent becomes white and opaque when heated, + | but on incipient fusion resumes its transparency and + | then fuses to a clear glass. + | +Andalusite | When powdered and treated with cobalt solution on + | charcoal, assumes a blue color. + | +Apophyllite | Fuses to a frothy white glass. + | +Axinite | Imparts a green color to the blowpipe flame, owing to + | the presence of boracic acid. This reaction is + | especially distinct, if the mineral be previously mixed + | with fluorspar and bisulphate of potassa. + | +Beryl | Sometimes gives a chromium reaction in borax and + | microcosmic salt. + | +Chabasite | Fuses to a white enamel. + | +Chondrodite | Evolves fluorine in the glass tube, both when heated + | alone and with microcosmic salt. It sometimes also + | gives off a trace of water. + | +Chrysoberyl | Is unattacked by carbonate of soda. With nitrate of + | cobalt on charcoal the finely powdered mineral + | assumes a blue color. + | +Datholite | Fuses to a clear glass and colors the flame green. + | +Diallage | Frequently gives off water in small quantity. + | +Fuchsite | Gives the chromium reaction with borax and microcosmic + | salt. + | +Gadolinite | That from Hitteroe, if heated in a partially covered + | platinum spoon to low redness, glows suddenly and + | brilliantly. + | +Hauyne | Affords the sulphur reaction both on charcoal and when + | fused with potassa. It contains both sulphur and + | sulphuric acid. + | +Hypersthene | As Diallage. + | +Kyanite | As Andalusite. + | +Lapis Lazuli | Fuses to a white glass, and when treated with carbonate + | of soda on charcoal, gives the sulphur reaction on + | silver. + | +Laumonite | When strongly heated, exfoliates and curls up. + | +Lepidolite | Colors the blowpipe flame crimson, from lithia; also + | gives the fluorine reaction with microcosmic salt. + | +Leucite | Some varieties, when treated with cobalt solution, + | assume a blue color. + | +Meerschaum | In the glass bulb frequently blackens and evolves an + | empyreumatic odor due to organic matter. When this is + | burnt off, it again becomes white, and if moistened + | with nitrate of cobalt solution and heated, assumes + | a pink color. + | +Okenite | Behaves as Apophyllite. + | +Olivine | Some varieties give off fluorine, when fused with + | microcosmic salt. + | +Pectolite | Similar to Apophyllite. + | +Petalite | Imparts a slight crimson color to the flame, like + | Lepidolite. + | +Prehnite | As Chabasite. + | +Pycnite | Assumes a blue color, when treated with nitrate of + | cobalt. Gives the fluorine reaction with microcosmic + | salt. + | +Pyrope | Gives the chromium reaction with borax and microcosmic + | salt. + | +Scolecite | Similar to Laumonite, but more marked. + | +Scapolite | Occasionally contains a small quantity of lithia, and + | colors the flame red when fused with fluorspar and + | bisulphate of potassa. + | +Sodalite | If mixed with one-fifth its volume of oxide of copper, + | moistened to make the mixture cohere, and a small + | portion placed upon charcoal and heated with the blue + | oxidizing flame, the outer flame will be colored + | intensely blue from chloride of copper. + | + | +Spodumene | When not too strongly heated, colors the blowpipe + | flame red, when more strongly, yellow. + | +Stilbite | As Chabasite. + | +Topaz | When heated, remains clear. Otherwise as Pycnite. + | +Tourmaline | Gives the boracic acid reaction with flourspar and + | bisulphate of potassa. + | +Wollastonite | Colors the blowpipe flame faintly red from lime. + | +Zircon | The colored varieties become white or colorless and + | transparent, when heated. Is only slightly attacked + | by carbonate of soda. +______________|________________________________________________________ + + + * * * * * + + URANIUM. + + * * * * * + +Mineral. Pitchblende + +Formula. [.U][...U=] essentially. + +Behavior + + (1) in glass-bulb. Evolves some water and a small quantity of + sulphur, sulphide of arsenic and metallic + arsenic. + + (2) in open tube. Evolves SO^{2} and a white sublimate of + arsenious acid. + + (3) on charcoal. Gives off arsenical fumes. + + (4) in forceps. III. Colors the flame blue beyond the assay, + owing to the presence of Pb. Sometimes also + green towards the point, due to Cu. + + (5) in borax. The roasted mineral affords the uranium + reaction. + + (6) in mic. salt. As borax. Also a small residue of silica. + + (7) with carb. soda. Infusible. Affords the characteristic Pb + incrustation, and sometimes yields minute + particles of Cu. + + (8) Special reactions. -- + + + * * * * * + +Mineral. Uranium ochre + +Formula. + [...U=][.H]^{2}. +Behavior + + (1) in glass-bulb. Evolves water and assumes a red color. + + (2) in open tube. -- + + (3) on charcoal. V. In reducing flame assumes a green color. + + + (4) in forceps. -- + + (5) in borax. Gives the uranium reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. -- + + (8) Special reactions. -- + + + * * * * * + +Mineral. Uranite + +Formula. ([.Ca] +[...U=]^{2})[.....]P + 8[.H]. + +Behavior + + (1) in glass-bulb. Evolves water and becomes yellow and opaque. + + (2) in open tube. -- + + (3) on charcoal. Fuses with intumescence to a black bead having a + semi-crystalline surface. + + (4) in forceps. -- + + (5) in borax. Gives the uranium reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Forms an infusible yellow slag. + + (8) Special reactions. Gives the PO^{5} reaction. + + * * * * * + +Mineral. Chalcolite + +Formula. ([.Cu]+[...U=]^{2})[.....P] + 8[.H]. + +Behavior + + (1) in glass-bulb. As uranite. + + (2) in open tube. -- + + (3) on charcoal. As uranite. + + (4) in forceps. As uranite. + + (5) in borax. In the oxidizing flame gives a green bead, which + in the reducing flame becomes of an opaque red, + from Cu. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. In reducing flame yields a metallic bead of Cu. + + (8) Special reactions. As uranite. + + * * * * * + + IRON. + + * * * * * + +Mineral. Iron pyrites + +Formula. FeS^{2}. + +Behavior + + (1) in glass-bulb. Gives a considerable yellow sublimate of + sulphur, and sometimes sulphide of arsenic. Also + HS. + + (2) in open tube. Sulphurous acid and sometimes arsenious acid are + evolved. + + (3) on charcoal. Gives off some sulphur, which burns with a blue + flame. Residue fuses to a magnetic bead. + + (4) in forceps. -- + + (5) in borax. The roasted mineral gives a strong iron + reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Fuses to a black mass, which spreads out on + charcoal and gives the sulphur reaction on + silver. + + (8) Special reactions. -- + + * * * * * + +Mineral. Magnetic pyrites + +Formula. + [,Fe]^{5}[,,,Fe=]. +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. Evolves sulphurous acid. + + (3) on charcoal. Fuses to a magnetic bead black on the surface, + and with a yellow shining fracture. + + (4) in forceps. -- + + (5) in borax. As iron pyrites. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As iron pyrites. + + (8) Special reactions. -- + + * * * * * + +Mineral. Mispickel + +Formula. FeAs + FeS^{2}. + +Behavior + + (1) in glass-bulb. A red sublimate of AsS^{2} is first formed and + then a black sublimate of metallic arsenic. + + (2) in open tube. Sulphurous and arsenious acids are evolved, the + latter forming a white sublimate. + + (3) on charcoal. Gives off much arsenic forming a white + incrustation and fuses to a magnetic globule. + + (4) in forceps. -- + + (5) in borax. As iron pyrites. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As iron pyrites. + + (8) Special reactions. -- + + * * * * * + +Mineral. Magnetic iron ore + +Formula. Fe^{3}O^{4} + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. In the blue flame, fuses on edges and remains + magnetic. + + (5) in borax. Gives the iron reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. -- + + (8) Special reactions. -- + + * * * * * + +Mineral. Specular iron + Red haematite + +Formula. Fe^{2}O^{3} + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. V. In the blue flame is converted into + Fe^{2}O^{4}, and then behaves as the preceding. + + (5) in borax. As magnetic iron ore. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. -- + + (8) Special reactions. -- + + * * * * * + +Mineral. Göthite + +Formula. [...Fe][.H]. + +Behavior + + (1) in glass-bulb. Evolves water. + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. As specular iron. + + (5) in borax. As specular iron. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. -- + + (8) Special reactions. -- + + * * * * * + +Mineral. Franklinite + +Formula. ([.Fe][.Zn][.Mn]) ([...Fe=][...Mn=]). + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. -- + + (3) on charcoal. Forms a white incrustation on the charcoal, + which moistened with cobalt solution assumes a + green color. + + (4) in forceps. V. In the blue flame fuses on edges and and + becomes magnetic. + + (5) in borax. Gives the iron and manganese reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Affords a considerable white incrustation of + ZnO. + + (8) Special reactions. Gives a strong manganese reaction with nitre and + carbonate of soda. + + * * * * * + +Mineral. Ilmenite + +Formula. [...Ti=] and [...Fe=]. + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. V. In reducing flame fuses on edges and becomes + magnetic. + + (5) in borax. Gives the iron reaction. + + (6) in mic. salt. In oxidizing flame exhibits the iron reaction. + In reducing flame assumes a deep brownish red + color. + + (7) with carb. soda. -- + + (8) Special reactions. -- + + * * * * * + +Mineral. Chromic iron + +Formula. [.Fe][...Cr=]. + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. As the preceding. + + (5) in borax. Dissolves slowly and gives the chromium + reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. On platinum foil with nitre and carbonate of + soda affords a yellow mass of chromate of + potassa. + + (8) Special reactions. -- + + * * * * * + +Mineral. Lievrite + +Formula. 3([.Fe][.Ca])^{3}[...Si] + 2[...Fe=][...Si]. + +Behavior + + (1) in glass-bulb. Occasionally gives off some water and turns + black. + + (2) in open tube. -- + + (3) on charcoal. Fuses to a black globule, which in the reducing + flame becomes magnetic. + + (4) in forceps. I. In reducing flame is magnetic. + + (5) in borax. Gives the iron reaction. + + (6) in mic. salt. Gives the iron and silica reactions. + + (7) with carb. soda. Fuses to a black opaque bead. + + (8) Special reactions. Generally gives the manganese reaction with + nitre and carbonate of soda. + + * * * * * + +Mineral. Chloropal + +Formula. [...Fe=][...Si]^{2} + 3[.H]. + +Behavior + + (1) in glass-bulb. Decrepitates more or less, gives off much water + and turns black. + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. V. Loses color and turns black. + + (5) in borax. Gives the iron reaction. + + (6) in mic. salt. Gives the iron and silica reaction. + + (7) with carb. soda. Fuses to a transparent green glass. + + (8) Special reactions. -- + + * * * * * + +Mineral. Green earth + +Formula. [...Si],[.Fe],[...Al=],[.Na],[.K],[.H], etc. + +Behavior + + (1) in glass-bulb. Gives off water and becomes darker in color. + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. V. In reducing flame fuses on edges and colors + the outer flame yellow ([.Na]) or violet ([.K]). + + (5) in borax. As the preceding. + + (6) in mic. salt. As the preceding. + + (7) with carb. soda. Forms a slaggy mass. + + (8) Special reactions. -- + + * * * * * + +Mineral. Siderite + +Formula. [.Fe][..C]. + +Behavior + + (1) in glass-bulb. Occasionally decrepitates. Gives off CO^{2} and + turns black and magnetic. + + (2) in open tube. -- + + (3) on charcoal. As in glass bulb. + + (4) in forceps. Behaves similarly to the magnetic oxide. + + (5) in borax. Gives the iron and manganese reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Behaves as an oxide. With nitre and carbonate of + soda on platinum generally gives the manganese + reaction. + + (8) Special reactions. In acid dissolves with effervescense. + + * * * * * + +Mineral. Copperas + +Formula. [.Fe][...S] + 7[.H]. + +Behavior + + (1) in glass-bulb. Gives off water, and, when strongly heated, + SO^{2} and SO^{3}, which reddens litmus paper. + + (2) in open tube. Evolves water and SO^{2}, which may be + recognized by its odor. + + (3) on charcoal. Loses water and SO^{2}, and is converted into + [...Fe=]. + + (4) in forceps. Gives off H and SO^{2}, and then behaves as the + magnetic oxide. + + (5) in borax. The roasted mineral affords an iron reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Forms sulphide of sodium and oxide of iron. The + former is absorbed into the charcoal, and if cut + out and laid upon silver and moistened gives the + S reaction. + + (8) Special reactions. If dissolved in water, and a strip of + silver-foil be introduced into the solution, the + metal remains untarnished. + + * * * * * + +Mineral. Vivianite + +Formula. [.Fe]^{3}[.....P] + 8[.H]. + +Behavior + + (1) in glass-bulb. Gives off water. + + (2) in open tube. -- + + (3) on charcoal. Froths up and then fuses to a grey metallic + bead. + + (4) in forceps. As on charcoal. Singes flame green ([.....P]). + + (5) in borax. Gives the iron reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. In reducing flame becomes magnetic and fuses to + a black saggy mass. + + (8) Special reactions. -- + + * * * * * + +Mineral. Iriphyline + +Formula. ([.Fe][.Mn][.Li])^{3}[.....P]. + +Behavior + + (1) in glass-bulb. Gives off water, having an alkaline reaction, + and assumes a metallic lustre resembling + graphite. + + (2) in open tube. -- + + (3) on charcoal. Fuses readily to a black magnetic bead with a + metallic lustre. + + (4) in forceps. I. On platinum wire colors the flame crimson + ([.Li]) and green ([.....P]), towards the point + fuses to a black magnetic bead. + + (5) in borax. Gives the iron and manganese reactions. + + (6) in mic. salt. Gives the iron reaction which overpowers that of + the manganese. + + (7) with carb. soda. Forms an infusible porous mass, which under + the reducing flame becomes magnetic. + + (8) Special reactions. Gives the manganese reaction with nitre and + carbonate of soda on platinum foil. + + * * * * * + +Mineral. Scorodite + +Formula. [...Fe=][.....As] + 4[.H]. + +Behavior + + (1) in glass-bulb. Evolves water. + + (2) in open tube. Gives off water and AsO^{3}. + + (3) on charcoal. Emits arsenical fume and in the reducing flame + fuses to a magnetic mass having a metallic + lustre. + + (4) in forceps. I. As on charcoal. Colors the outer flame + blue. + + (5) in borax. The roasted mineral gives an iron reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As alone on charcoal. + + (8) Special reactions. Gives the arsenic reactions. + + * * * * * + +Mineral. Cube ore + +Formula. [.Fe]^{3}[.....As] + + [...Fe=]^{3}[.....As]^{2} + 18[.H]. + +Behavior + + (1) in glass-bulb. Evolves much water. + + (2) in open tube. As the preceding. + + (3) on charcoal. As the preceding. + + (4) in forceps. As the preceding. + + (5) in borax. As the preceding. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As the preceding. + + (8) Special reactions. As the preceding. + + * * * * * + + MANGANESE. + + * * * * * + +Mineral. Manganblende + +Formula. MnS. + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. Gives off SO^{2} and becomes greyish green on + surface. + + (3) on charcoal. Is slowly roasted and converted into oxide. + + (4) in forceps. V. + + (5) in borax. The roasted mineral gives a strong manganese + reaction. + + (6) in mic. salt. In the unroasted state, dissolves with much + ebullition and detonation due to elimination of + sulphide of phosphorus. The bead then exhibits + the characteristic violet color of manganese. + + (7) with carb. soda. Forms a slaggy mass, which laid on silver and + moistened, gives the sulphur reaction. + + (8) Special reactions. -- + + * * * * * + +Mineral. Pyrolusite + +Formula. [..Mn]. + +Behavior + + (1) in glass-bulb. Frequently gives off a small quantity of water + and, when strongly heated, oxygen. + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. V. + + (5) in borax. Gives the manganese reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Forms a slaggy mass. + + (8) Special reactions. -- + + * * * * * + +Mineral. Manganite + +Formula. [...Mn=][.H]. + +Behavior + + (1) in glass-bulb. Gives off much water. + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. V. Exfoliates slightly. + + (5) in borax. As the preceding. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As the preceding. + + (8) Special reactions. -- + + * * * * * + +Mineral. Psilomelane + +Formula. ([.Ba],[.Ca],[.Mg],[.K]) [..Mn] + [.H]. + +Behavior + + (1) in glass-bulb. Gives off water and, when + strongly heated, oxygen. + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. V. Colors flame faintly green(Ba) and red + towards the point (Ca). + + (5) in borax. As pyrolusite. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As pyrolusite. + + (8) Special reactions. -- + + * * * * * + +Mineral. Wad + +Formula. [..Mn],[.Mn],[.H], also [...Fe=],[...Al=], + [.Ba],[.Cu],[...Pb],[...Si], etc. + +Behavior + + (1) in glass-bulb. Gives off water. + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. V. Colors flame variously according to its + composition. + + (5) in borax. Gives the manganese reaction, more or less + modified by the presence of other oxides. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As pyrolusite. + + (8) Special reactions. Various according to composition. When strongly + heated and then moistened has an alkaline + reaction on red litmus paper. + + * * * * * + +Mineral. Rhodonite + +Formula. [.Mn]^{3}[...Si]^{2}. + +Behavior + + (1) in glass-bulb. Gives off more or less water. + + (2) in open tube. -- + + (3) on charcoal. Under a strong flame fuses to a brown opaque + bead. + + (4) in forceps. II. As on charcoal. + + (5) in borax. In the oxidizing flame gives the manganese + reaction. In reducing flame the iron reaction. + + (6) in mic. salt. As in borax, but leaves an insoluble siliceous + skeleton. + + (7) with carb. soda. With a small quantity of the alkali fuses to a + black bead. With a larger quantity forms a slag. + + (8) Special reactions. -- + + * * * * * + +Mineral. Diallogite + +Formula. [.Mn][..C]. + +Behavior + + (1) in glass-bulb. Frequently decrepitates and gives off more or + less water. + + (2) in open tube. -- + + (3) on charcoal. If strongly heated and moistened has an alkaline + reaction on litmus paper due to the presence of + Ca. + + (4) in forceps. V. Frequently colors the flame slightly red. + + (5) in borax. Gives the manganese and iron reactions. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Forms an infusible slag. + + (8) Special reactions. In warm acid dissolves with much effervescence. + + + * * * * * + +Mineral. Triplite + +Formula. ([..Mn][.Fe])^{4}[.....P]. + +Behavior + + (1) in glass-bulb. Generally gives off more or less + water. + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. I. Colors the outer blowpipe flame green + ([.....P]). + + (5) in borax. Gives the manganese and iron reactions. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Forms an infusible mass. + + (8) Special reactions. -- + + * * * * * + + NICKEL AND COBALT. + + * * * * * + +Mineral. Millerite + +Formula. NiS. + +Behavior + + + (1) in glass-bulb. -- + + (2) in open tube. Evolves SO^{2}. + + (3) on charcoal. Fuses with much ebullition to a magnetic bead. + + (4) in forceps. -- + + (5) in borax. The roasted mineral gives a nickel reaction, + slightly modified by small quantities of iron + and copper. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Fuses to a slaggy mass, which on silver gives + the sulphur reaction. + + (8) Special reactions. -- + + * * * * * + +Mineral. Coppernickel + +Formula. Ni^{2}As. + +Behavior + + (1) in glass-bulb. Gives off a little AsO^{3}. + + (2) in open tube. Gives off much AsO^{3} and some SO^{2} and falls + to powder. + + (3) on charcoal. Fuses to a magnetic bead, with the evolution of + arsenic, which colors the flame blue. + + (4) in forceps. -- + + (5) in borax. The arsenical bead obtained by fusing the + mineral on charcoal, if fused upon the same + support with borax successively added and + removed, gives firstly an iron reaction, then + cobalt if present, and lastly nickel. + + (6) in mic. salt. If the residual bead which has been treated with + borax be further treated with microcosmic salt, + the nickel reaction will be obtained and + sometimes a slight copper reaction. + + (7) with carb. soda. -- + + (8) Special reactions. Affords a sublimate of metallic arsenic when + treated with cyanide of potassium. + + * * * * * + +Mineral. Smaltine + +Formula. CoAs. + +Behavior + + + (1) in glass-bulb. When strongly heated generally evolves metallic + arsenic. + + (2) in open tube. Gives a crystalline sublimate of AsO^{3}. Also + some SO^{2}. + + (3) on charcoal. Gives off fumes of arsenic, and fuses to a dark + grey magnetic bead, very brittle, colors flame + blue. + + (4) in forceps. -- + + (5) in borax. As the preceding, but the cobalt being in large + excess requires some time for its perfect + oxidation, before the nickel reaction is + exhibited. + + (6) in mic. salt. Gives the cobalt reaction, and after the cobalt + has been, removed that of nickel. + + (7) with carb. soda. -- + + (8) Special reactions. As the preceding. + + * * * * * + +Mineral. Glance cobalt + +Formula. CoS^{2} + CoAs. + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. As the preceding, but gives off more SO^{2}. + + (3) on charcoal. Gives off S and As, and fuses to a magnetic + bead. Colors flame blue. + + (4) in forceps. -- + + (5) in borax. Gives a cobalt and slight iron reaction when + treated as the preceding minerals. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Gives a sulphur reaction of silver. + + (8) Special reactions. As the preceding. + + * * * * * + +Mineral. Nickel glance + +Formula. NiS^{2} + NiAs. + +Behavior + + (1) in glass-bulb. Decrepitates and gives an orange colored + sublimate of AsS^{2}. + + (2) in open tube. As the preceding. + + (3) on charcoal. As the preceding. + + (4) in forceps. -- + + (5) in borax. As copper nickel. + + (6) in mic. salt. Gives the nickel reaction occasionally somewhat + obscured by cobalt. + + (7) with carb. soda. As the preceding. + + (8) Special reactions. As copper nickel. + + * * * * * + +Mineral. Ulmannite + +Formula. NiS^{2} + Ni(AsSb)^{2}. + +Behavior + + (1) in glass-bulb. Gives a slight white sublimate of SbO^{3} and + more or less AsS^{3}. + + (2) in open tube. Gives off thick fumes of SbO^{3} and SbO^{5} + with AsO^{3} and SO^{2}. + + (3) on charcoal. As glance cobalt, but accompanied by dense fumes + of SbO^{3}. + + (4) in forceps. -- + + (5) in borax. As copper nickel. + + (6) in mic. salt. As the preceding. + + (7) with carb. soda. As the preceding. + + (8) Special reactions. As copper nickel generally, but arsenic is not + always present. + + * * * * * + +Mineral. Cobalt pyrites + +Formula. ([,Co][,Ni][,Fe]) ([,,,Co=][,,,Ni=][,,,Fe=]). + +Behavior + + (1) in glass-bulb. When strongly heated gives off sulphur and + becomes brown. + + (2) in open tube. Gives off much SO^{2} and a small quantity of + AsO^{3}. + + (3) on charcoal. In the reducing flame small fragments fuse with + the evolution of sulphur to a magnetic bead + having a bronze colored fracture. + + (4) in forceps. -- + + (5) in borax. In the oxidizing flame on charcoal gives a + violet colored glass. In the reducing flame the + nickel is reduced and may collected in a gold + bead. When the nickel is removed, the glass + exhibits a slight iron reaction while warm. + + (6) in mic. salt. As in borax, but the reduction of the nickel is + more difficult than in the latter flux. + + (7) with carb. soda. As glance cobalt. + + (8) Special reactions. As copper nickel, but the amount of arsenic is + usually very small. + + * * * * * + +Mineral. Emerald nickel + +Formula. [.Ni]^{3}[..C] + 6[.H]. + +Behavior + + (1) in glass-bulb. Gives off much water and turns black. + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. -- + + (5) in borax. Dissolves with much effervescence and gives the + nickel reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Forms a slaggy mass. + + (8) Special reactions. In warm dilute HCl dissolves with much + effervescence. + + * * * * * + +Mineral. Cobalt Bloom + +Formula. [.Co]^{3}[.....As] + 8[.H]. + +Behavior + + (1) in glass-bulb. Gives off water. + + (2) in open tube. -- + + (3) on charcoal. Evolves arsenical fumes and in the reducing + flame fuses to a dark grey bead of arsenide of + cobalt. + + (4) in forceps. In the point of the blue flame fuses and colors + the outer flame blue (As). + + (5) in borax. Gives the cobalt reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. -- + + (8) Special reactions. Gives off arsenic with cyanide of potassium in + glass tube. + + * * * * * + +Mineral. Earthy cobalt + +Formula. [.Mn],[.Co],[.Cu],[.Fe],[.H], etc. + +Behavior + + (1) in glass-bulb. Gives off water. + + (2) in open tube. -- + + (3) on charcoal. Emits a slight smell of arsenic, but does not + fuse. + + (4) in forceps. Colors the flame blue. + + (5) in borax. In oxidizing flame gives the cobalt reaction + which obscures those of [.Mn], [.Cu], etc. In + reducing flame occasionally gives the [.Cu] + reaction. + + (6) in mic. salt. As in borax. If a saturated bead be treated on + charcoal with tin in the reducing flame for a + few seconds, the [.Cu] reaction is sometimes + obtained. + + (7) with carb. soda. Forms an infusible mass. + + (8) Special reactions. With carbonate of soda and nitre on platinum + foil, gives a strong manganese reaction. + + * * * * * + + ZINC. + + * * * * * + +Mineral. Zincblende + +Formula. ZnS. + +Behavior + + (1) in glass-bulb. Decrepitates strongly. + + (2) in open tube. Evolves SO and becomes white or yellow if + containing iron. + + (3) on charcoal. V. In the reducing flame incrusts the charcoal + with ZnO; also with CdO, if that metal be + present. + + (4) in forceps. -- + + (5) in borax. The roasted mineral gives a zinc reaction, and + sometimes a slight iron reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As alone on charcoal. Moreover colors the flame + blue. The fused alkali gives a S reaction on + silver. + + (8) Special reactions. -- + + * * * * * + +Mineral. Red oxide of zinc + +Formula. [.Zn]. + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. -- + + (3) on charcoal. In the reducing flame forms a thin incrustation + of oxide of zinc on the charcoal. + + (4) in forceps. V. + + (5) in borax. Generally gives a manganese and slight iron + reaction in addition to that of zinc. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. On charcoal, forms a thick incrustation of ZnO. + + (8) Special reactions. With carbonate of soda and nitre on platinum + foil gives manganese reaction. + + * * * * * + +Mineral. Electric calamine + +Formula. 2[.Zn]^{3}[...Si] + 3[.H] + +Behavior + + (1) in glass-bulb. Gives off water and becomes white and opaque. + + (2) in open tube. -- + + (3) on charcoal. -- + + (4) in forceps. V. + + (5) in borax. Dissolves to a clear glass, which cannot be + rendered opaque by the intermittent flame. + + (6) in mic. salt. Dissolves to a clear glass, which becomes opaque + on cooling. Silica remains insoluble. + + (7) with carb. soda. With carbonate of soda alone is infusible. With + 2 parts of alkali and 1 of borax fuses to a + glass and sets free [.Zn], which incrusts the + charcoal. + + (8) Special reactions. -- + + * * * * * + +Mineral. Calamine + +Formula. [.Zn][..C]. + +Behavior + + (1) in glass-bulb. Gives off CO^{2} and becomes opaque. + + (2) in open tube. -- + + (3) on charcoal. As the red oxide. Sometimes also gives a lead + incrustation. + + (4) in forceps. V. + + (5) in borax. Gives a zinc reaction and frequently an iron and + manganese reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Forms a thick incrustation of zinc, sometimes + also of [.Pb] and [.Co]. + + (8) Special reactions. Dissolves with much effervescence in cold acid. + + * * * * * + + BISMUTH. + + * * * * * + +Mineral. Native bismuth + +Formula. Bi. + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. Fuses and is converted into a yellow oxide. + + (3) on charcoal. Fuses to a bead and incrusts the charcoal with + oxide. + + (4) in forceps. -- + + (5) in borax. The oxide formed upon charcoal gives the bismuth + reactions. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. -- + + + (8) Special reactions. -- + + * * * * * + +Mineral. Bismuthine + +Formula. BiS. + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. Fuses with ebullition and gives of S and SO^{2}. + + + (3) on charcoal. Fuses with much spirting and in the reducing + flame yields a metallic bead and incrusts the + charcoal with oxide. + + (4) in forceps. -- + + (5) in borax. The oxide obtained upon charcoal gives the + bismuth reactions. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As alone on charcoal. The fused alkali gives the + sulphur reaction on silver. + + (8) Special reactions. -- + + * * * * * + +Mineral. Bismuthblende + +Formula. [...Bi=]^{2}[...Si]^{3}. + +Behavior + + (1) in glass-bulb. Turns yellow and, when strongly heated, fuses. + + (2) in open tube. -- + + (3) on charcoal. Fuses with ebullition to a brown globule forming + an incrustation of [...Bi=] on the charcoal. + + (4) in forceps. I. Fuses with ease to a yellow bead, coloring + the outer flame bluish green, especially if + moistened with HCl. This color is due to + [.....P]. + + (5) in borax. Gives the bismuth and also an iron reaction. + + (6) in mic. salt. As in borax, but leaves a silicious skeleton. + + (7) with carb. soda. Fuses to a yellow mass. The bismuth is then + reduced to the metallic state and partially + volatilized, incrusting the charcoal beyond. + + (8) Special reactions. -- + + * * * * * + +Mineral. Tetradymite + +Formula. Bi, Te, S. + +Behavior + + (1) in glass-bulb. Occasionally decrepitates and then fuses, + forming a greyish white sublimate immediately + above the mineral fragment. + + (2) in open tube. Fuses and gives off white fumes, part of which + pass up the tube and part deposit immediately + above the mineral. This latter if heated fuses + to clear drops (TeO^{3}). The mineral residue + becomes surrounded by fused [...Bi=], + characterized by its yellow color. + + (3) on charcoal. Fuses to a metallic bead, colors the outer flame + bluish green (Te and Se) and incrusts the + charcoal around with the orange [...Bi=], beyond + which is a white incrustation partly consisting + of [...Te]. + + (4) in forceps. -- + + (5) in borax. The yellow oxide obtained upon charcoal gives + the bismuth reaction, and the white incrustation + of bismuth and telluric acid. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. In the reducing flame yields a bead of metallic + bismuth, part of which is part of the tellurium + volatilized and incrusts the charcoal around. + + (8) Special reactions. The fused alkaline mass gives the sulphur + reaction on silver. Also gives the tellurium + reaction with charcoal and carbonate of soda. + + * * * * * + + LEAD. + + * * * * * + +Mineral. Galena + +Formula. PbS. + +Behavior + + (1) in glass-bulb. Generally decrepitates and gives off a small + quantity of sulphur. + + (2) in open tube. Gives off SO^{2}, and when strongly heated, a + white sublimate of [.Pb], [.S]. + + (3) on charcoal. Fuses and is reduced affording a bead of + metallic lead, and forming an incrustation of + PbO on the charcoal. Colors the outer flame + blue. + + (4) in forceps. -- + + (5) in borax. The oxide formed upon charcoal gives the lead + reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As alone on charcoal. The fused alkali gives a + sulphur reaction on silver. + + (8) Special reactions. -- + + * * * * * + +Mineral. Clausthalite + +Formula. PbSe. + +Behavior + + (1) in glass-bulb. Decrepitates slightly. + + (2) in open tube. Forms a sublimate of selenium, which is grey + when thickly deposited, and red when thin. + + (3) on charcoal. Gives off fumes smelling strongly of selenium + and coloring the flame blue. In the reducing + flame fuses partially and incrusts the charcoal + with Se and PbO. After some time a black + infusible mass alone remains. + + (4) in forceps. -- + + (5) in borax. The infusible residue obtained upon charcoal + gives an iron and sometimes copper and cobalt + reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. With carbonate of soda, oxalate of potash yields + a metallic bead, the fused alkali laid upon + silver and moistened produces a stain similar to + that produced by sulfur. + + (8) Special reactions. -- + + * * * * * + +Mineral. Jamesonite + +Formula. [,Pb]^{3}[,,,Sb]^{2}. + +Behavior + + (1) in glass-bulb. Fuses and gives off some sulphur, sulphide of + antimony and antimony which condense in the neck + of the bulb. + + (2) in open tube. Fuses and emits dense white fumes of SbO^{3}, + which pass off and redden blue litmus paper. + + (3) on charcoal. Fuses with great ease evolving much SbO^{3} and + PbO, which incrusts the charcoal around the + mineral. When the fumes have ceased, a small + bead of metallic lead remains. + + (4) in forceps. -- + + (5) in borax. The yellow incrustation formed upon charcoal + gives the reaction of lead, and the white those + of antimony. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As alone on charcoal. The fused alkali gives the + sulphur reaction on silver. + + (8) Special reactions. -- + + * * * * * + +Mineral. Minium + +Formula. Pb^{3}O^{4}. + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. -- + + (3) on charcoal. Is reduced first to litharge (PbO) and then to + metallic lead which forms the usual + incrustation. + + (4) in forceps. Colors the outer flame blue. + + (5) in borax. Gives the lead reactions. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As alone on charcoal. + + (8) Special reactions. -- + + * * * * * + +Mineral. Mendipite + +Formula. PbCl + 2PbO. + +Behavior + + (1) in glass-bulb. Decrepitates slightly and assumes a yellow + color. + + (2) in open tube. -- + + (3) on charcoal. Fuses readily and is reduced to metallic lead + with the evolution of acid fumes. Forms a white + incrustation of PbCl, and a yellow one of PbO. + + (4) in forceps. As the preceding. + + (5) in borax. As the preceding. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As alone on charcoal. + + (8) Special reactions. Gives the chlorine reaction with CuO and + microcosmic salt. + + * * * * * + +Mineral. Cerusite + +Formula. [.Pb][..C]. + +Behavior + + (1) in glass-bulb. Decrepitates, gives off CO^{2}, turns yellow and + fuses. + + (2) in open tube. -- + + (3) on charcoal. Is reduced to metallic lead, incrusting the + charcoal around with PbO. + + (4) in forceps. As the preceding. + + (5) in borax. Gives the lead reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As alone on charcoal. + + (8) Special reactions. In nitric acid dissolves with much + effervescence. + + * * * * * + +Mineral. Anglesite + +Formula. [.Pb][...S]. + +Behavior + + (1) in glass-bulb. Decrepitates and gives off a small quantity of + water. + + (2) in open tube. -- + + (3) on charcoal. In the oxidizing flame fuses to a clear bead, + which becomes opaque on cooling. In reducing + flame is reduced with much ebullition to a + metallic bead and incrusts the charcoal around + with PbO. + + (4) in forceps. As the preceding. + + (5) in borax. Gives the lead reaction and occasionally a + slight iron and manganese reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Is reduced yielding a metallic lead bead. The + fused alkaline mass gives a sulphur reaction on + silver. + + (8) Special reactions. -- + + * * * * * + +Mineral. Pyromorphite + +Formula. PbCl + 3[.Pb]^{3}[.....P]. + +Behavior + + (1) in glass-bulb. Decrepitates, and when strongly heated for some + time, gives a slight white sublimate of PbCl. + + (2) in open tube. -- + + (3) on charcoal. In oxidizing flame fuses to a bead having a + crystalline surface on cooling, and forms a thin + film of PbCl on the charcoal In reducing flame + fuses without reduction and on cooling assumes a + polyhedral form. Incrusts the charcoal slightly + with PbO. + + (4) in forceps. Fuses and colors the flame blue. + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. Is reduced yielding a metallic bead and + incrusting the charcoal with PbO. + + (8) Special reactions. Gives the chlorine reaction with microcosmic + salt and CuO. Also the phosphoric acid + reactions. + + * * * * * + +Mineral. Mimetene + +Formula. PbCl+ 3[.Pb]^{3}[.....As] + +Behavior + + (1) in glass-bulb. As the preceding. + + (2) in open tube. -- + + (3) on charcoal. Fuses, but less easily than the preceding, gives + off AsO^{3} and incrusts the charcoal with + PbCl. Finally is reduced to a metallic bead and + forms an incrustation of PbO. + + (4) in forceps. As the preceding. + + (5) in borax. The oxide formed on charcoal gives the lead + reactions. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As the preceding. + + + + (8) Special reactions. Gives the chlorine reaction. + + * * * * * + +Mineral. Vanadinite + +Formula. PbCl + 3[.Pb]^{3}[...V]? + +Behavior + + (1) in glass-bulb. As pyromorphite. + + (2) in open tube. -- + + (3) on charcoal. The powdered mineral fuses fuses to a black + shining mass, which in the reducing flame + affords a metallic bead. Incrusts the charcoal + first with a white film of PbCl and afterwards + with PbO. + + (4) in forceps. As pyromorphite. + + (5) in borax. Dissolves readily to a clear glass, which, in + the oxidizing flame, is yellow, while hot, and + colorless when cold. In reducing flame becomes + opaque, and on cooling green. + + (6) in mic. salt. In oxidizing flame is yellow while hot, becoming + paler on cooling. In reducing flame brown while + warm, and emerald green when cold. + + (7) with carb. soda. On platinum wire fuses to a yellow bead, which + is crystalline on cooling. On charcoal yields a + button of metallic lead. + + (8) Special reactions. With microcosmic salt and CuO, gives the chlorine + reaction. If fused in a platinum spoon with from + 3 to 4 times its volume of [.K],[...S]^{2} it + forms a fluid yellow mass having an orange color + when cold. + + * * * * * + +Mineral. Crocoisite + +Formula. [.Pb][...Cr]. + +Behavior + + (1) in glass-bulb. Decrepitates violently and assumes a dark color. + + (2) in open tube. -- + + (3) on charcoal. Fuses and detonates yielding Cr^{2}O^{3} and + metallic lead, and forming an incrustation of + PbO on the charcoal. + + (4) in forceps. As pyromorphite. + + (5) in borax. Dissolves readily and colors the glass yellow + while warm, and green when cold. (See Chromium + reaction.) + + (6) in mic. salt. As in borax. + + (7) with carb. soda. On platinum foil gives a dark yellow mass, which + becomes paler on cooling. On charcoal yields a + metallic button. + + (8) Special reactions. Treated as above with [.K],[...S]^{2} forms a + violet colored mass, which on solidifying + becomes reddish and on cooling pale grey. + + * * * * * + +Mineral. Molybdate of lead + +Formula. [.Pb][...M]. + +Behavior + + (1) in glass-bulb. As the preceding. + + (2) in open tube. -- + + (3) on charcoal. Fuses and is partly absorbed into the charcoal + leaving a globule of metallic lead, which is + partially oxidized and incrusts the charcoal. + + (4) in forceps. As pyromorphite. + + (5) in borax. Dissolves readily and gives the molybdena + reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Yields metallic lead. + + (8) Special reactions. Fused as above with [.K],[...S]^{2} forms a yellow mass, + which becomes white on cooling. If this be + dissolved in water and a piece of zinc + introduced into the solution, the latter becomes + blue. + + * * * * * + +Mineral. Scheeletine + +Formula. [.Pb][...W]. + +Behavior + + (1) in glass-bulb. Decrepitates more or less. + + (2) in open tube. -- + + (3) on charcoal. Fuses to a bead incrusting the charcoal with + PbO. The bead on cooling is crystalline and has + a dark metallic surface. + + (4) in forceps. As pyromorphite. + + (5) in borax. Dissolves to a clear colorless glass, which in + the reducing flame becomes yellow, and on + cooling grey and opaque. + + (6) in mic. salt. Dissolves to a clear colorless glass, which + in the reducing flame assumes a dusky blue + color. After a time becomes opaque. + + (7) with carb. soda. As the preceding. + + (8) Special reactions. With carbonate of soda and nitre gives the + manganese reaction. + + * * * * * + + COPPER. + + * * * * * + +Mineral. Native Copper + +Formula. Cu. + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. -- + + (3) on charcoal. Fuses to a brilliant metallic bead, which on + cooling becomes covered with a coating of black + oxide. + + (4) in forceps. Fuses and colors the outer flame blue. + + (5) in borax. In the oxidizing flame dissolves and then gives + the copper reactions. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. -- + + (8) Special reactions. -- + + * * * * * + +Mineral. Vitreous Copper + +Formula. Cu^{2}S. + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. Evolves SO^{2} and, when pulverized and gently + heated for some time is converted into CuO. + + (3) on charcoal. Fuses to a bead, which spirts considerably and + gives off SO^{2}. When pulverized and gently + roasted, is converted into CuO. + + (4) in forceps. -- + + (5) in borax. The roasted mineral gives the copper reaction, + and sometimes also a slight iron-reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. In the reducing flame is decomposed, forming NaS + and metallic copper. If the former be cut out + and laid upon silver, it gives the sulfur + reaction. + + (8) Special reactions. -- + + * * * * * + +Mineral. Copper pyrites + +Formula. [,Cu=][,,,Fe=]. + +Behavior + + (1) in glass-bulb. Decrepitates, sometimes gives a sublimate of + sulphur and becomes bronze colored on the + surface. + + (2) in open tube. Evolves SO^{2} and is finally converted into a + dark red mixture of Fe^{2}O^{3} and CuO. + + (3) on charcoal. Fuses readily with much ebullition and is + magnetic on cooling. + + (4) in forceps. -- + + (5) in borax. As the preceding; but when the copper has been + removed by reducing on charcoal, the bead shows + a strong iron color. + + (6) in mic. salt. As the preceding, but the color in the oxidizing + flame is green, owing to the presence of iron. + + (7) with carb. soda. Yields a bead of metallic copper and some + magnetic oxide of iron which remains on the + charcoal. The fused gives a sulphur reaction on + silver. + + (8) Special reactions. -- + + * * * * * + +Mineral. Fahlerz + +Formula. ([,Cu=][,Ag][,Fe][,Zn])^{4} ([,,,Sb][,,,As]). + +Behavior + + (1) in glass-bulb. Sometimes decrepitates, fuses, and when very + strongly heated, gives a red sublimate of + [,,,Sb] with [...Sb], also sometimes a black + sublimate of [,Hg] and occasionally [,,,As]. + + (2) in open tube. Fuses and gives off thick fumes of SbO^{3} and + SO^{2}, also generally AsO^{3}, leaving a black + infusible residue. If Hg be present, it is + sublimed and condenses in the tube in small + drops. + + (3) on charcoal. Fuses to a bead, which fumes strongly and + incrusts the charcoal with SbO^{3}, and + sometimes ZnO, which cannot be volatilized. + Emits a strong smell of arsenic. + + (4) in forceps. -- + + (5) in borax. The residue obtained on charcoal thoroughly + roasted gives a copper reaction, and when the + latter has been removed by reduction upon + charcoal, an iron reaction. + + (6) in mic. salt. As in the preceding. + + (7) with carb. soda. With this flux and a little borax yields a bead + of metallic copper; on silver, the alkaline mass + gives a sulphur reaction. + + (8) Special reactions. If the copper bead obtained by fusing upon + carbonate of soda be cupelled with assay lead, a + silver bead will be obtained. Or if dissolved in + nitric acid and a drop or two of HCl added, a + white precipitate of AgCl will be formed, which + may be collected and reduced with carbonate of + soda upon charcoal. + + * * * * * + +Mineral. Tennatite + +Formula. ([,Cu=][,Fe=])^{4}[,,,As]. + +Behavior + + (1) in glass-bulb. Decrepitates occasionally and gives a red + sublimate of [,,,As]. + + (2) in open tube. Evolves [..S] and [...As], which condense and + form a white sublimate. + + (3) on charcoal. Fuses to a magnetic bead giving of arsenical and + sulphurous fumes. + + (4) in forceps. -- + + (5) in borax. As the preceding. + + (6) in mic. salt. As the preceding. + + (7) with carb. soda. Yields a copper bead and metallic iron in the + form of a dark grey powder. The fused alkali + gives the sulphur reaction. + + (8) Special reactions. -- + + * * * * * + +Mineral. Bournonite + +Formula. ([,Pb]^{2}[,Cu=])[,,,Sb]. + +Behavior + + (1) in glass-bulb. Decrepitates giving off sulfur and, when + strongly heated, [,,,Sb] and [...Sb]. + + (2) in open tube. Evolves thick white fumes of [...Sb],[.....Sb] + and [.Pb][...Sb]. Also [.S]. + + (3) on charcoal. Fuses readily and incrusts the charcoal with + [...Sb] and [.Pb] leaving a dark colored bead. + + (4) in forceps. -- + + (5) in borax. If the bead obtained on charcoal be fused on + that support in the reducing flame with borax, a + slight iron reaction is obtained, and after a + time a copper reaction. + + (6) in mic. salt. As with borax. + + (7) with carb. soda. Yields a bead of metallic copper and lead and + incrusts the charcoal with [...Sb] and [.Pb]. + The alkaline mass laid on silver and moistened + gives the sulphur reaction. + + (8) Special reactions. -- + + * * * * * + +Mineral. Red oxide of copper + +Formula. Cu^{2}O + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. Is converted into the black oxide CuO. + + (3) on charcoal. In the reducing flame is reduced, forming a + bead of metallic copper. + + (4) in forceps. Fuses and colors the the flame emerald + green, or if previously moistened with HCl, + blue. + + (5) in borax. Gives the copper reaction. + + (6) in mic. salt. As with borax. + + (7) with carb. soda. Is reduced to a bead of metallic copper. + + (8) Special reactions. -- + + + * * * * * + +Mineral. Atacamite + +Formula. CuCl + 3[.Cu] + 6[.H]. + +Behavior + + (1) in glass-bulb. Gives off much water, having an acid + reaction, on test paper, and forms a light + grey sublimate of CuCl. + + (2) in open tube. -- + + (3) on charcoal. Fuses, colors the flame blue, forms a brown + and a pale grey incrustation on the + charcoal, and is reduced to metallic copper, + leaving a small quantity of slag. + + (4) in forceps. Fuses and colors the outer flame intensely + blue and green towards the point. + + (5) in borax. Gives the copper reactions. + + (6) in mic. salt. As with borax. + + (7) with carb. soda. Is reduced, yielding a bead of metallic + copper. + + (8) Special reactions. -- + + + * * * * * + +Mineral. Dioptase + +Formula. [.Cu]^{3}[...Si]^{2} + 3[.H]. + +Behavior + + (1) in glass-bulb. Gives off water and turns black. + + (2) in open tube. -- + + (3) on charcoal. In the oxidizing flame becomes black. In the + reducing flame red. + + (4) in forceps. V. Colors the outer flame intensely green. + + (5) in borax. Gives the copper reactions. + + (6) in mic. salt. As with borax. The silica remains + undissolved. + + + (7) with carb. soda. With a small quantity of carbonate of soda + fuses to a bead, which on cooling is opaque + and has a red fracture. With more alkali + forms a slag, containing little beads of + reduced copper. + + + (8) Special reactions. -- + + + * * * * * + +Mineral. Malachite + +Formula. [.Cu]^{2}[..C] + [.H]. + +Behavior + + (1) in glass-bulb. Gives off water and turns black. + + (2) in open tube. -- + + (3) on charcoal. Fuses to a bead with a strong flame is + reduced to metallic copper. + + (4) in forceps. Fuses and colors the outer flame brilliantly + green. + + (5) in borax. Gives the copper reaction. + + (6) in mic. salt. As with borax. + + (7) with carb. soda. Yields metallic copper. + + + (8) Special reactions. Dissolves in HCl with much effervescence. + + * * * * * + +Mineral. Blue vitriol + +Formula. [.Cu][...S] + 5[.H]. + +Behavior + + (1) in glass-bulb. Intumesces, gives off water and becomes + white. + + (2) in open tube. Strongly heated is decomposed, given off + SO^{2} and being converted into CuO. + + (3) on charcoal. As in the glass-bulb. Then fuses, coloring + the outer flame green, and is reduced to + metallic copper and [,Cu=]. + + (4) in forceps. Fuses and colors the outer flame blue. + + (5) in borax. The roasted mineral gives copper reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Yields metallic copper. The alkaline mass + laid on silver gives S reaction. + + (8) Special reactions. Gives the sulphuric acid reaction. + + + * * * * * + +Mineral. Libethenite + +Formula. [.Cu]^{4}[.....P] + 2[.H]. + +Behavior + + (1) in glass-bulb. Gives off water and turns black. + + (2) in open tube. -- + + (3) on charcoal. Gradually heated, turns black and fuses to a + bead, having a core of metallic copper. + + (4) in forceps. Fuses but does not color the flame + distinctly. On cooling is black and + crystalline. + + (5) in borax. Gives the copper reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. With much of the alkali is decomposed, + yielding metallic copper. With small + portions successively added first fuses and + then intumesces, fuses with a strong flame, + and is then absorbed into the charcoal, + leaving metallic copper. + + (8) Special reactions. Gives the phosphoric acid reaction. + + * * * * * + +Mineral. Olivenite + +Formula. [.Cu]^{4}([.....As][.....P]) + [.H]. + +Behavior + + (1) in glass-bulb. Gives off water. + + (2) in open tube. -- + + (3) on charcoal. Fuses with detonation and the evolution of + arsenical fumes to a brittle regulus, brown + externally and having a white fracture. + + (4) in forceps. Fuses and colors the outer flame green. On + cooling has a crystalline surface. + + (5) in borax. Gives the copper reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Is reduced, yielding metallic copper. + + (8) Special reactions. Gives the arsenic reactions. + + + * * * * * + + ANTIMONY. + + * * * * * + +Mineral. Native antimony + +Formula. Sb. + +Behavior + + (1) in glass-bulb. Fuses and, when strongly heated, volatilizes + being redeposited in the tube as a dark grey + sublimate. + + (2) in open tube. Fuses and gives off dense white fumes, which + are partly redeposited on the tube. + Sometimes also gives off arsenical fumes in + small quantity. + + (3) on charcoal. Fuses and gives off dense white fumes, which + thickly incrust the charcoal and color the + flame blue immediately beyond the assay. + + (4) in forceps. -- + + (5) in borax. The oxide formed upon charcoal gives the + antimony reactions. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. -- + + (8) Special reactions. The incrustation on the charcoal, if treated + with nitrate of cobalt assumes the + characteristic green color. + + * * * * * + +Mineral. Grey antimony + +Formula. SbS^{3}. + +Behavior + + (1) in glass-bulb. Fuses readily and occasionally gives off a + small quantity of sulphur. Strongly heated + forms a brown sublimate of SbS^{3} and + SbO^{3}. + + (2) in open tube. Fuses and gives off SO^{2}, which passes off + up the tube, and dense white fumes of + SbO^{3} and SbO^{5} which are partly + deposited in the tube. + + (3) on charcoal. Fuses and is partly absorbed by the charcoal + and partly volatilized, incrusting the + charcoal with the characteristic white + oxides. Colors the flame blue. + + (4) in forceps. -- + + (5) in borax. As the preceding. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. Fuses and is reduced, yielding metallic + antimony, which behaves as the preceding + mineral upon charcoal. The alkaline mass + gives the sulphur reaction. + + (8) Special reactions. As the preceding. + + * * * * * + +Mineral. Antimony blende + +Formula. [,,,Sb]^{2} + [...Sb]. + +Behavior + + (1) in glass-bulb. Fuses easily, gives off first SbO^{3} and + afterwards an orange colored sublimate. + Strongly heated, is decomposed and gives a + black sublimate, which becomes brown on + cooling. + + (2) in open tube. As the preceding. + + (3) on charcoal. As the preceding. + + (4) in forceps. -- + + (5) in borax. As native antimony. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As the preceding. + + + (8) Special reactions. As native antimony. + + * * * * * + +Mineral. White antimony + +Formula. SbO^{3}. + +Behavior + + (1) in glass-bulb. Is sublimed and recondensed in the neck of + the tube. + + (2) in open tube. As in the glass-bulb. + + (3) on charcoal. Fuses with the evolution of dense white + fumes, which incrust the surface of the + charcoal. In the reducing flame is partly + reduced, yielding metallic antimony. Colors + flame blue. + + (4) in forceps. Fuses and is volatilized, coloring the outer + flame blue. + + (5) in borax. Gives the antimony reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. In the reducing flame is reduced, yielding + metallic antimony. + + (8) Special reactions. As native antimony. + + * * * * * + + ARSENIC. + + * * * * * + +Mineral. Native arsenic + +Formula. As. + +Behavior + + (1) in glass-bulb. Sublimes without fusion and recondenses as a + dark grey metallic sublimate, sometimes + leaving a small residue. + + (2) in open tube. If gently heated in a good current of air + passes off as AsO^{3}, which is partly + condensed as a white sublimate in the upper + part of the tube. + + (3) on charcoal. Passes off as AsO^{3}, which thinly incrusts + the charcoal beyond the assay. + + (4) in forceps. Colors the flame blue. + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. -- + + (8) Special reactions. -- + + * * * * * + +Mineral. Realgar + +Formula. AsS^{2}. + +Behavior + + (1) in glass-bulb. Fuses, enters into ebullition and is + sublimed as a transparent red sublimate. + + (2) in open tube. Gently heated passes off as SO^{2} and + AsO^{3}, the latter of which is redeposited + in the upper part of the tube. + + (3) on charcoal. Fuses and passes off as arsenious and + sulphurous acids. + + (4) in forceps. Fuses and colors the flame blue. + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. As on charcoal, except that the S combines + with the alkali forming NaS, which on silver + gives the sulphur reaction. + + (8) Special reactions. -- + + * * * * * + +Mineral. Orpiment + +Formula. AsS^{3}. + +Behavior + + (1) in glass-bulb. As the preceding, except that the sublimate + is of a dark yellow color when cold. + + (2) in open tube. As the preceding. + + (3) on charcoal. As the preceding. + + (4) in forceps. As the preceding. + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. As the preceding. + + (8) Special reactions. -- + + * * * * * + +Mineral. White arsenic + +Formula. AsO^{3}. + +Behavior + + (1) in glass-bulb. Sublimes without fusion and re-condenses in + white crystals. + + (2) in open tube. -- + + (3) on charcoal. Sublimes and is partly recondensed on + charcoal forming a white incrustation. + + (4) in forceps. Colors the flame blue. + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. -- + + (8) Special reactions. Heated with charcoal in a glass-tube sealed + at one end, is reduced and metallic arsenic + sublimes. + + * * * * * + + MERCURY. + + * * * * * + +Mineral. Native mercury + +Formula. Hg. + +Behavior + + (1) in glass-bulb. Volatilizes with little or no residue and + recondenses in neck of bulb. + + (2) in open tube. -- + + (3) on charcoal. Is volatilized. + + (4) in forceps. -- + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. -- + + (8) Special reactions. -- + + * * * * * + +Mineral. Cinnabar + +Formula. HgS. + +Behavior + + (1) in glass-bulb. Volatilizes sometimes leaving a slight + earthy residue, and re-condenses as a black + sulphide. + + (2) in open tube. If gently heated is decomposed into metallic + mercury, which volatilizes and recondenses + in the upper part of the tube, and SO^{2}, + which passes off as is easily recognized by + its odor and bleaching properties. + + (3) on charcoal. Is volatilized, generally leaving a small + earthy residue. + + (4) in forceps. -- + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. With carbonate of soda and cyanide of + potassium is decomposed and metallic mercury + volatilized. + + (8) Special reactions. When in the preceding experiment the mercury + has been entirely dissipated, the alkaline + residue laid on silver gives a sulphur + reaction. + + * * * * * + +Mineral. Native amalgam + +Formula. AgHg^{2}. + +Behavior + + (1) in glass-bulb. As native mercury, but leaves a residue of + pure silver. + + (2) in open tube. -- + + (3) on charcoal. The mercury volatilizes leaving the silver, + which fuses to a bead, and, in the oxidizing + flame, incrusts the charcoal with its + characteristic oxide. + + (4) in forceps. -- + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. -- + + (8) Special reactions. -- + + * * * * * + + SILVER. + + * * * * * + +Mineral. Native silver + +Formula. Ag. + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. -- + + (3) on charcoal. Fuses and in a strong oxidizing flame forms + an incrustation of dark brown oxide on the + charcoal. If any antimony be present, it + affords a crimson incrustation. + + (4) in forceps. -- + + (5) in borax. Gives the silver reactions. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. -- + + (8) Special reactions. -- + + * * * * * + +Mineral. Antimonial silver + +Formula. Ag^{2}Sb. + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. Gives off dense white fumes, which are + partly deposited in the tube. + + (3) on charcoal. Fuses, fumes strongly, forming a white + incrustation, and when the antimony is + nearly expelled a crimson one, a nearly pure + silver bead remains. + + (4) in forceps. -- + + (5) in borax. The incrustation formed on charcoal gives an + antimony reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As alone on charcoal. + + (8) Special reactions. -- + + * * * * * + +Mineral. Silver glance + +Formula. AgS. + +Behavior + + (1) in glass-bulb. -- + + (2) in open tube. Gives off sulphurous acid. + + (3) on charcoal. Gives off SO^{2} and is reduced to metallic + silver. If impure, a small quantity of slag + also remains. + + (4) in forceps. -- + + (5) in borax. The residual slag (if any) obtained upon + charcoal gives an iron reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. As alone on charcoal. The alkaline mass gives + a sulphur reaction on polished silver. + + (8) Special reactions. -- + + * * * * * + +Mineral. Stephanite + +Formula. [,Ag]^{6}[,,,Sb]. + +Behavior + + (1) in glass-bulb. Decrepitates, fuses and gives a slight + sublimate of sulphide of antimony. + + (2) in open tube. Fuses and gives off SO^{2} and dense white + antimonial fumes. + + (3) on charcoal. Fuses and incrusts the charcoal with + antimonious acid, leaving Ag with some + antimony. If the flame be continued, a red + incrustation is formed and finally a bead of + pure silver remains surrounded by a small + slag. + + (4) in forceps. -- + + (5) in borax. The residual slag obtained on the charcoal + gives an iron and copper reaction. + + (6) in mic. salt. As in borax. + + (7) with carb. soda. The silver is reduced and the antimony + passes off in dense fumes. The fused alkali + gives the sulphur reaction on silver. + + (8) Special reactions. -- + + * * * * * + +Mineral. Pyargyrite + +Formula. [,Ag]^{3}[,,,Sb]. + +Behavior + (1) in glass-bulb. Sometimes decrepitates, fuses readily, and, + when strongly heated, gives a red sublimate + of SbS^{3}. + + (2) in open tube. As in the preceding. + + (3) on charcoal. Fuses with much spirting and covers the + charcoal with antimonial fumes. When the + residual AgS is heated for some time in the + oxidizing flame, a bead of pure silver is + obtained. + + (4) in forceps. -- + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. As the preceding. + + (8) Special reactions. -- + + * * * * * + +Mineral. Proustite + +Formula. [,Ag]^{3}[,,,As]. + +Behavior + + (1) in glass-bulb. Fuses and at a low red heat affords a small + sublimate of AsS^{3}. + + (2) in open tube. Gradually heated it gives off AsO^{3} and + SO^{2}. Sometimes also antimony fumes. + + (3) on charcoal. As the preceding, except that a large + quantity of AsO^{3} and but little SbO^{3} + are given off. + + (4) in forceps. -- + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. As stephanite, except that much arsenic is + given off and but little antimony. + + (8) Special reactions. -- + + * * * * * + +Mineral. Horn silver + +Formula. AgCl. + +Behavior + + (1) in glass-bulb. Fuses, but undergoes no further change. + + (2) in open tube. -- + + (3) on charcoal. Fuses readily in the oxidizing flame. In the + reducing flame is slowly reduced yielding + metallic silver. + + (4) in forceps. -- + + (5) in borax. -- + + (6) in mic. salt. -- + + (7) with carb. soda. Is rapidly reduced to metallic silver. + + (8) Special reactions. If cut up into small pieces mixed with oxide + of copper and then heated before the + oxidizing flame upon charcoal, it colors the + flame blue. + + + THE END. + + + * * * * * + +Transcriber's Notes: + + Text italicized in the original book is surrounded by '_'. + + This book had many columnar tables, often split across pages. These + have been transformed in data sheets for readability. + + The notation ^{#} is used for superscripted numbers, indicating + the composition of the various chemical compounds. + + Some of the element symbols were differenced by markings that + were not defined in the book, but are supposed to be valence + markings. These have been transcribed as follows: + + '.' or ',' above element symbol [?.Symbol] or [?,Symbol] + '-' above element symbol [=Symbol] + '-' through element symbol [Symbol=] + ... + So [...Al] where the original text had Al + _ + [=M] where the original text had M + ,,, + [,,,Sb] where the original text had Sb + ... + [...Fe=] where the original text had Fe, line through the Fe. + + + + + + + + + + + + + + +End of the Project Gutenberg EBook of A System of Instruction in the +Practical Use of the Blowpipe, by Anonymous + +*** END OF THIS PROJECT GUTENBERG EBOOK USE OF THE BLOWPIPE *** + +***** This file should be named 15576-8.txt or 15576-8.zip ***** +This and all associated files of various formats will be found in: + https://www.gutenberg.org/1/5/5/7/15576/ + +Produced by Curtis Weyant, Victoria Woosley and the PG +Online Distributed Proofreading Team at www.pgdp.net. + + +Updated editions will replace the previous one--the old editions +will be renamed. + +Creating the works from public domain print editions means that no +one owns a United States copyright in these works, so the Foundation +(and you!) can copy and distribute it in the United States without +permission and without paying copyright royalties. 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