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diff --git a/8391-h/8391-h.htm b/8391-h/8391-h.htm new file mode 100644 index 0000000..196b60c --- /dev/null +++ b/8391-h/8391-h.htm @@ -0,0 +1,5642 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> +<html> +<head> +<meta name="generator" content="HTML Tidy, see www.w3.org"> +<meta http-equiv="Content-Type" content= +"text/html; charset=ISO-8859-1"> +<title>The Project Gutenberg eBook of Scientific American +Supplement, July 9, 1881</title> +<style type="text/css"> +<!-- +body {margin-left: 15%; margin-right: 15%; background-color: white} +img {border: 0;} +h1,h2,h3 {text-align: center;} +.ind {margin-left: 10%; margin-right: 10%;} +hr {text-align: center; width: 50%;} +.ctr {text-align: center;} +--> +</style> +</head> +<body> + + +<pre> + +Project Gutenberg's Scientific American Supplement, No. 288, by Various + +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: Scientific American Supplement, No. 288 + July 9, 1881 + +Author: Various + +Posting Date: October 10, 2012 [EBook #8391] +Release Date: June, 2005 +First Posted: July 6, 2003 + +Language: English + +Character set encoding: ISO-8859-1 + +*** START OF THIS PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN SUPPL., NO. 288 *** + + + + +Produced by Olaf Voss, Don Kretz, Juliet Sutherland, Charles +Franks and the Online Distributed Proofreading Team. + + + + + + +</pre> + + +<p class="ctr"><a href="images/1a.png"><img src= +"images/1a_th.png" alt=""></a></p> + +<h1>SCIENTIFIC AMERICAN SUPPLEMENT NO. 288</h1> + +<h2>NEW YORK, JULY 9, 1881</h2> + +<h4>Scientific American Supplement. Vol. XI, No. 288.</h4> + +<h4>Scientific American established 1845</h4> + +<h4>Scientific American Supplement, $5 a year.</h4> + +<h4>Scientific American and Supplement, $7 a year.</h4> + +<hr> +<table summary="Contents" border="0" cellspacing="5"> +<tr> +<th colspan="2">TABLE OF CONTENTS.</th> +</tr> + +<tr> +<td valign="top">I.</td> +<td><a href="#1">ENGINEERING AND MECHANICS--Dry Air Refrigerating +Machine. 5 figures. Plan, elevation, and diagrams of a new English +dry air refrigerator</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#2">Thomas' Improved Steam Wheel. 1 figure</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#3">The American Society of Civil Engineers. Address +of President Francis, at the Thirteenth Annual Convention, at +Montreal. The Water Power of the United States, and its +Utilization</a></td> +</tr> + +<tr> +<td valign="top">II.</td> +<td><a href="#4">TECHNOLOGY AND CHEMISTRY.--Alcohol in Nature. Its +presence in earth, atmosphere, and water. 6 figures. Distillatory +apparatus and (magnified) iodoform crystals from snow water, from +rain water, from vegetable mould, etc.</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#5">Detection of Alcohol in Transparent Soaps. By H. +JAY</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#6">On the Calorific Power of Fuel, and on Thompson's +Calorimeter. By J.W. THOMAS</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#7">Explosion as an Unknown Fire Hazard. A suggestive +review of the conditions of explosions, with curious +examples</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#8">Carbon. Symbol C. Combining weight. 12. By T. A. +POOLEY Second article on elementary chemistry written for +brewers</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#9">Manufacture of Soaps and their Production. By W. +J. MENZIES</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#10">The Preparation of Perfume Pomades. 1 figure. +"Ensoufflage" apparatus for perfumes</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#11">Organic Matter in Sea Water</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#12">Bacteria Life. Influence of heat and various +gases and chemical compounds on bacteria life</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#13">On the Composition of Elephant's Milk. By Dr. +CHAS. A. DOREMUS. Comparison of elephant's milk with that of ten +other mammals</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#14">The Chemical Composition of Rice. Maize, and +Barley. By J. STEINER</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#15">Petroleum Oils. Character and properties of the +various distillates of crude petroleum. Fire risks attending the +use of the lighter petroleum oils</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#16">Composition of the Petroleum of the Caucasus. By +P. SCHULZENBERGER and N. TONINE</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#17">Notes on Cananga Oil. or Ilang-Ilang Oil. By F. +A. FLÜCKIGER. 1 figure. Flower and leaf of Cananga +odorata</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#18">Chian Turpentine, and the Tree which Produces It. +By Dr. STIEPOWICH. of Chios, Turkey</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#19">On the Change of Volume which Accompanies the +Galvanic Deposition of a Metal. By M. E. BOUTY</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#20">Analysis of the Rice Soils of Burmah. By R. +ROMANIC, Chemical Examiner, British Burmah</a></td> +</tr> + +<tr> +<td valign="top">III.</td> +<td><a href="#21">PHYSICS AND PHYSICAL APPARATUS.--Seyfferth's +Pyrometer. 7 figures.--Pyrometer with electric indicator.--Method +of mounting by means of a cone on vacuum apparatus.--Mounting by +means of a sleeve.--Mounting by means of a thread on a tube.-- +Mounting by means of a clasp in reservoirs.--The pyrometer mounted +on a bone-black furnace.--Mounted on a brick furnace</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#22">Delicate Scientific Instruments. By EDGAR L. +LARKIN. An interesting description of the more powerful and +delicate instruments of research used by modern scientists and +their marvelous results</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#23">The Future Development of Electrical Appliances. +Lecture by Prof. J. W. PERRY before the London Society of +Arts.--Methods and units of electrical measurements</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#24">Researches on the Radiant Matter of Crookes and +the Mechanical Theory of Electricity. By Dr. W. F. GINTL</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#25">Economy of the Electric Light. W. H. PREECE'S +Experiments Investigations</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#26">On the Space Protected by a Lightning Conductor. +By WM. H. PREECE.--5 figures</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#27">Photo-Electricity of Fluor Spar Crystals</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#28">The Aurora Borealis and Telegraph Cables</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#29">The Photographic Image: What It Is. By T. H. +MORTON. 1 figure.--Section of sensitive plate after exposure and +during development</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#30">Gelatine Transparencies for the Lantern</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#31">An Integrating Machine. By C. V. BOYS.--1 +figure</a></td> +</tr> + +<tr> +<td></td> +<td><a href="#32">Upon a Modification of Wheatstone's Microphone +and its Applicability to Radiophonic Researches. By ALEX. GRAHAM +BELL,--2 figures</a></td> +</tr> + +<tr> +<td valign="top">IV.</td> +<td><a href="#33">ARCHITECTURE.--Suggestions in Architecture, 1 +figure.--A pair of English cottages. By A. CAWSTON</a></td> +</tr> +</table> + +<hr> +<p><a name="4"></a></p> + +<h2>ALCOHOL IN NATURE--ITS PRESENCE IN THE EARTH, WATER, AND +ATMOSPHERE.</h2> + +<p>A Chemist of merit, Mr. A. Müntz, who has already made +himself known by important labors and by analytical researches of +great precision, has been led to a very curious and totally +unexpected discovery, on the subject of which he has kindly given +us information in detail, which we place before our readers.[1] Mr. +Müntz has discovered that arable soil, waters of the ocean and +streams, and the atmosphere contain traces of alcohol; and that +this compound, formed by the fermentation of organic matters, is +everywhere distributed throughout nature. We should add that only +infinitesimal quantities are involved--reaching only the proportion +of millionths--yet the fact, for all that, offers a no less +powerful interest. The method of analysis which has permitted the +facts to be shown is very elegant and scrupulously exact, and is +worthy of being made known.</p> + +<p>[Footnote 1: The accompanying engravings have been made from +drawings of the apparatus in the laboratory of which Mr. Müntz +is director, at the Agronomic Institute.]</p> + +<p class="ctr"><a href="images/1b.png"><img src= +"images/1b_th.png" alt= +"FIG. 1.--FIRST DISTILLATORY APPARATUS."></a></p> + +<p class="ctr">FIG. 1.--FIRST DISTILLATORY APPARATUS.</p> + +<p class="ctr"><img src="images/1c.png" alt= +"FIG. 2.--SECOND DISTILLATORY APPARATUS."></p> + +<p class="ctr">FIG. 2.--SECOND DISTILLATORY APPARATUS.</p> + +<p>Mr. Müntz's method of procedure is as follows: He submits +to distillation three or four gallons of snow, rain, or sea water +in an apparatus such as shown in Fig. 1. The part which serves as a +boiler, and which holds the liquid to be distilled, is a milk-can, +B. The vapors given off through the action of the heat circulate +through a leaden tube some thirty-three feet in length, and then +traverse a tube inclosed within a refrigerating cylinder, T, which +is kept constantly cold by a current of water. They are finally +condensed in a glass flask, R, which forms the receiver. When 100 +or 150 cubic centimeters of condensed liquid (which contains all +the alcohol) are collected in the receiver, the operations are +suspended. The liquid thus obtained is distilled anew in a second +apparatus, which is analogous to the preceding but much smaller +(Fig. 2). The liquid is heated in the flask, B, and its vapor, +after traversing a glass worm, is condensed in the tube, T. The +operation is suspended as soon as five or six cubic centimeters of +the condensed liquid have been collected in the test-tube, R. The +latter is now removed, and to its liquid contents, there is added a +small quantity of iodine and carbonate of soda. The mixture is +slightly heated, and soon there are seen forming, through +precipitation, small crystals of iodoform. Under such +circumstances, iodoform could only have been formed through the +presence of an alcohol in the liquid. These analytical operations +are verified by Mr. Müntz as follows: He distills in the same +apparatus three to four gallons of chemically pure distilled water, +and ascertains positively that under these conditions iodine and +carbonate of soda give absolutely no reaction. Finally, to complete +the demonstration and to ascertain the approximate quantity of +alcohol contained in natural waters, he undertakes the double +fractional distillation of a certain quantity of pure water to +which he has previously added a one-millionth part of alcohol. +Under these circumstances the iodine and carbonate of soda give a +precipitate of iodoform exactly similar to that obtained by +treating natural waters.</p> + +<p class="ctr"><img src="images/1d.png" alt=""></p> + +<p class="ctr">Fig. 3.--IODOFORM CRYSTALS OBTAINED<br> +DIRECTLY (greatly magnified).</p> + +<p class="ctr"><img src="images/1e.png" alt=""></p> + +<p class="ctr">FIG. 4,--IODOFORM CRYSTALS OBTAINED WITH<br> +RAIN WATER.</p> + +<p>In the case of arable soil, Mr. Müntz stirs up a weighed +quantity of the material to be analyzed in a certain proportion of +water, distills it in the smaller of the two apparatus, and detects +the alcohol by means of the same operation as before.</p> + +<p class="ctr"><img src="images/1f.png" alt= +"FIG. 5.--IODOFORM CRYSTALS OBTAINED WITH SNOW WATER."></p> + +<p class="ctr">FIG. 5.--IODOFORM CRYSTALS OBTAINED WITH SNOW +WATER.</p> + +<p>The formation of iodoform by precipitation under the action of +iodine and carbonate of soda is a very sensitive test for alcohol. +Iodoform has sharply defined characters which allow of its being +very easily distinguished. Its crystalline form, especially, is +entirely typical, its color is pale yellowish, and, when it is +examined under the microscope, it is seen to be in the form of +six-pointed stars precisely like the crystalline form of snow. Mr. +Müntz has not been contented to merely submit the iodoform +precipitates obtained by him to microscopical examination, but has +preserved the aspect of his preparations by means of +micro-photography. The figures annexed show some of the most +characteristic of the proofs. Fig. 1 shows crystals of iodoform +obtained with pure water to which one-millionth part of alcohol had +been added. Fig. 2 exhibits the form of the crystals obtained with +rain water; and Fig. 3, those with water. Fig. 4 shows crystals +obtained with arable soil or garden mould. The first of Mr. +Müntz's experiments were made about four years ago; but since +that time he has treated a great number of rain and snow waters +collected both at Paris and in the country. At every distillation +all the apparatus was cleansed by prolonged washing in a current of +steam; and, in order to confirm each analysis, a corresponding +experiment was made like the one before mentioned. More than eighty +trials gave results which were exactly identical. The quantity of +alcohol contained in rain, snow, and sea waters may be estimated at +from one to several millionths. Cold water and melted snow seem to +contain larger proportions of it than tepid waters. In the waters +of the Seine it is found in appreciable quantities, and in sewage +waters the proportions increase very perceptibly. Vegetable mould +is quite rich in it; indeed it is quite likely that alcohol in its +natural state has its origin in the soil through the fermentation +of the organic matters contained therein. It is afterward +disseminated throughout the atmosphere in the state of vapor and +becomes combined with the aqueous vapors whenever they become +condensed. The results which we have just recorded are, as far as +known to us, absolutely new; they constitute a work which is +entirely original, which very happily goes to complete the history +of the composition of the soil and atmosphere, and which does great +credit to its author.--<i>La Nature</i>.</p> + +<p class="ctr"><img src="images/1g.png" alt= +"FIG. 6.--IODOFORM CRYSTALS OBTAINED WITH VEGETABLE MOULD."></p> + +<p class="ctr">FIG. 6.--IODOFORM CRYSTALS OBTAINED WITH VEGETABLE +MOULD.</p> + +<hr> +<p><a name="5"></a></p> + +<h2>DETECTION OF ALCOHOL IN TRANSPARENT SOAPS.</h2> + +<h3>By H. JAY.</h3> + +<p>It appears that every article manufactured with the aid of +alcohol is required on its introduction into France to pay duty on +the supposed quantity of this reagent which has been used in its +preparation. Certain transparent soaps of German origin are now met +with, made, as is alleged, without alcohol, and the author proposes +the following process for verifying this statement by +ascertaining--the presence or absence of alcohol in the +manufactured article: 50 grms. of soap are cut into very small +pieces and placed in a phial of 200 c.c. capacity; 30 grms. +sulphuric acid are then added, and the phial is stoppered and +agitated till the soap is entirely dissolved. The phial is then +filled up with water, and the fatty acids are allowed to collect +and solidify. The subnatant liquid is drawn off, neutralized, and +distilled. The first 25 c.c. are collected, filtered, and mixed, +according to the process of MM. Riche and Bardy for the detection +of alcohol in commercial methylenes, with ½ c.c. sulphuric +acid at 18° B., then with the same volume of permanganate (15 +grms. per liter), and allowed to stand for one minute. He then adds +8 drops of sodium hyposulphite at 33° B., and 1 c.c. of a +solution of magenta, 1 decigrm. per liter. If any alcohol is +present there appears within five minutes a distinct violet tinge. +The presence of essential oils gives rise to a partial reduction of +the permanganate without affecting the conversion of alcohol into +aldehyd.</p> + +<hr> +<p><a name="6"></a></p> + +<h2>ON THE CALORIFIC POWER OF FUEL, AND ON THOMPSON'S +CALORIMETER.</h2> + +<h3>By J.W. THOMAS, F.C.S., F.I.C.</h3> + +<p>A simple experiment, capable of yielding results which shall be +at least comparative, has long been sought after by large consumers +of coal and artificial fuel abroad in order to ascertain the +relative calorific power possessed by each description, as it is +well known that the proportion of mineral matter and the chemical +composition of coal differ widely. The determination of the ash in +coal is not a highly scientific operation; hence it is not +surprising that foreign merchants should have become alive to the +importance of estimating its quantity. While, however, the nature +and quantity of the ash can be determined without much difficulty, +the determination of the chemical composition of coal entails +considerable labor and skill; hence a method giving the calorific +power of any fuel in an exact and reliable manner by a simple +experiment is a great desideratum. This will become more obvious +when one takes into consideration the many qualities and variable +characters of the coals yielded by the South Wales and North of +England coal fields. Bituminous coals--giving some 65 per cent, of +coke--are preferred for some manufacturing purposes and in some +markets. Bituminous steam coals, yielding 75 per cent, of coke, are +highly prized in others. Semi-bituminous steam coals, yielding 80 +to 83 per cent, of coke, are most highly valued, and find the +readiest sale abroad; and anthracite steam coal (dry coals), giving +from 85 to 88 per cent, of coke (using the term "coke" as +equivalent to the non-volatile portion of the coal) is also +exported in considerable quantity. Now the estimation of the ash of +any of these varieties of coal would afford no evidence as to the +class to which that coal belongs, and there is no simple test that +will give the calorific power of a coal, and at the same time +indicate the degree of bituminous or anthracitic character which it +possesses.</p> + +<p>In order to obtain such information it is necessary that the +percentage of coke be determined together with the sulphur, ash, +and water, and these form data which at once show the nature of a +fuel and give some indication of its value. To ascertain the +quantity of the sulphur, ash, and water with accuracy involves more +skill and aptitude than can be bestowed by the non-professional +public; the consequence is that experiments entailing less time and +precision, like those devised by Berthier and Thompson, have been +tried more or less extensively. In France and Italy, Berthier's +method--slightly modified in some instances--has been long used. It +is as follows:</p> + +<p>70 grammes of oxide of lead (litharge) and 10 grammes of +oxychloride of lead are employed to afford oxygen for the +combustion of 1 gramme of fuel in a crucible. From the weight of +the button of lead, and taking 8,080 units as the equivalent of +carbon, the total heat-units of the fuel is calculated. This +experiment is very imperfect and erroneous upon scientific grounds, +since the hydrogen of the fuel is scarcely taken into account at +all. In the first place, hydrogen consumes only one quarter as much +oxygen as carbon, and, furthermore, two-ninths only of the heating +power of hydrogen is used as the multiplying number, viz., 8,080, +while the value of hydrogen is 34,462. In other words, +one-eighteenth only of the available hydrogen present in the fuel +is shown in the result obtained. Apart from this my experience of +the working of Berthier's method has been by no means satisfactory. +There is considerable difficulty in obtaining pure litharge, and it +is almost impossible to procure a crucible which does not exert a +reducing action upon the lead oxide. Some twelve months ago I went +out to Italy to test a large number of cargoes of coal with +Thompson's calorimeter, and since then this apparatus has +superseded Berthier's process, and is likely to come into more +general use. Like Berthier's method, Thompson's apparatus is not +without its disadvantages, and the purpose of this paper is to set +these forth, as well as to suggest a uniform method of working by +means of which the great and irreconcilable differences in the +results obtained by some chemists might be overcome. It has already +been observed that a coal rich in hydrogen shows a low heating +power by Berthier's method, and it will become evident on further +reflection that the higher the percentage of carbon the greater +will be the indicated calorific power. In fact a good sample of +anthracite will give higher results than any other class of coal by +Berthier's process. With Thompson's calorimeter the reverse is the +case, as the whole of the heating power of the hydrogen is taken +into account. In short, with careful working, the more bituminous a +coal is the more certain is it that its full heating power shall be +exerted and recorded, so far as the apparatus is capable of +indicating it; for when the result obtained is multiplied by the +equivalent of the latent heat of steam the product is always below +the theoretical heat units calculated from the chemical composition +of the coal by the acid of Favre and Silbermann's figures for +carbon and hydrogen. On the other hand, when the heating power of +coal low in hydrogen is determined by Thompson's calorimeter, much +difficulty is experienced in burning the carbon completely; hence a +low result is obtained. From a large number of experiments I have +found that when a coal does not yield more than 86 per cent, of +coke, it gives its full comparative heating power, but it is very +questionable if equal results will be worked out if the coke +exceeds the above amount although I have met with coals giving 87 +per cent. of coke which were perfectly manageable, though in other +cases the coal did not burn completely. It will be noted that the +non-volatile residue of anthracite is never as low as 86 per cent., +and this, together with the very dry steam coals and bastard +anthracite (found over a not inextensive tract of the South Wales +Coal field), form a series of coals, alike difficult to burn in +Thompson's calorimeter. Considerable experience has shown that in +no single instance was the true comparative heating power of +anthracite or bastard anthracite indicated. With a view to +accelerate the perfect combustion of these coals, sugar, starch, +bitumen, and bituminous coals--substances rich in hydrogen--were +employed, mixed in varying proportions with the anthracitic coal, +but without the anticipated effect. Coke was also treated in a like +manner. Without enlarging further upon these futile trials--all +carefully and repeatedly verified--the results of my experiments +and experience show that for coals of an anthracitic character, +yielding more than 87 per cent. of coke, or for coke itself, +Thompson's calorimeter is not suited as an indicator of their +comparative calorific power, for the simple reason that some of the +carbon is so graphitic in its nature that it will not burn +perfectly when mixed with nitrate and chlorate of potash. A sample +of very pure anthracite used in the experiments referred to, gave +90.4 per cent. of non-volatile residue, and only 0.84 per cent. of +ash. This coal was not difficult to experiment with, as combustion +started with comparative ease and proceeded quite rapidly enough, +but in every instance a portion of the carbon was unconsumed, and +consequently instead of about 13° of rise in temperature only +10° were recorded.</p> + +<p>Since the calorific power of a coal is determined by the number +of degrees Fahrenheit which a given quantity of water is raised in +temperature by a known weight of fuel, it follows that every care +should be taken that the experiment be performed under similar +atmospheric conditions. The oscillation of barometric pressure does +not appear to affect the working, but the temperature of the room +in which the work was done, and especially that of the water, are +most important considerations. It has been observed by some who +have used this apparatus--and I have frequently noticed it +myself--that the lower the temperature of the water is under which +the fuel is burnt the higher is the result found. This has been +explained on the assumption that the colder the water used, the +greater is the difference between the temperature of the room and +that of the water; hence it would be expedient that in all cases +when such experiments are made the same difference of temperature +between the air in the room and the water employed should always +exist. For example, if the temperature of the room were 70°, +and the water at 60°, then the same coal would give a like +result with the water at 40° and the room at 50°. This has +been regarded as the more evident, because the gases passing +through the water escape under favorable conditions of working at +the same temperature as the water, and are perfectly deprived of +any heat in excess of that possessed by the water. Under these +circumstances it would seem only reasonable that this assumption +should be correct. It was, however, found after a large number of +experiments upon the same sample of coal that this was not the +case. 30 grammes of coal which raises the temperature of the water +13.4°, when the water at starting was 60° and the room at +70°, gives 13.7° rise of temperature with the water at +40° and the room at 50°. Conversely, when the water is at +70° and the room at 80°, a lower result is obtained. The +explanation appears to be this: The gas which escapes from the +water was not in existence in the gaseous form previous to the +experiment, and the heat communicated to the gas being a definite +quantity it follows that the more the gas is cooled the greater the +proportion of chemical energy in the shape of heat will be utilized +and recorded as calorific power.</p> + +<p>In order, therefore, to make the experiment more simple and +workable at all temperatures, a sample of coal was selected, which +should be perfectly manageable and readily consumed. Appended is an +analysis of the coal employed (from Ebbw Vale, Monmouthshire):</p> + +<pre> + Composition per cent. +<br> +Carbon...............................88.33 +Hydrogen............................. 5.08 +Oxygen............................... 3.28 +Nitrogen............................. 0.55 +Sulphur.............................. 0.70 +Ash.................................. 1.26 +Water (moisture)..................... 0.80 + ----- + 100.00 +</pre> + +<p>In the following experiments the standard temperature of the +water was taken as 60° F., and as the coal gave 13.4° of +rise of temperature, 67° F. was selected as the standard room +temperature. The reason for this room temperature is obvious, for, +whatever heating effect the higher temperature of the room may have +upon the water in the cylinder during the time occupied by the +first half of the experiment, would be compensated for by the loss +sustained during the second half of the experiment, when the +temperature of the water exceeded that of the room. The mean of +numerous trials gave 13.4° F. rise of temperature, equal to +14.74 lb. of water per lb. of coal. When the water was at 50° +and the room at 57°, the mean of several experiments gave +13.5° rise of temperature. When the water was 40° at +starting and the room at 47°, 13.65° was the average rise +of temperature. Trials were made at intermediate temperatures, and +the results always showed that higher figures were recorded when +the water was coldest. With a view of getting uniformity in the +results it was thought well to make experiments, in order to find +out what temperature the room should be at, so that this coal might +give the same result with the water at 50°, 40°, or at +intermediate temperatures. Without going much into detail, it was +found that when the temperature of the room was at 40° and that +of the water 40°, and the experiment was rapidly and carefully +performed, 13.4° rise of temperature was given; but this result +could be obtained without special effort when the room was 42° +and the water 40° at starting. It is evident that the cooling +effect of the air in the room upon the water cylinder is very +appreciable when the water has reached 13° above that of the +room. When the water was at 50° and the room at 55°, the +coal gave 13.4° rise with ease and certainty, and it would not +be out of place to remark here that with those coals which burn +well in Thompson's calorimeter, the results of several trials are +remarkably uniform when properly performed. With the water at +70° and the room at 80°, a like result was worked out. +Experiments at intermediate temperatures were also carried out (see +table in sequel). It is true that the whole difference of +temperature we are dealing with in making these corrections is only +0.25, but 0.2 in the result, when multiplied by 537 to bring it +into calories, as is done by the authorities in Italy, makes more +than 100 heat units--a serious difference when 5d. per ton fine is +attached to every 100 calories lower than the number +guaranteed.</p> + +<p>Taking the latent heat of steam as 537° C., and multiplying +this number by 14.74, the evaporative power of the coal used in +these experiments, its equivalent in calories is 7,915. From the +analysis of this coal, disregarding the nitrogen and deducting an +equivalent of hydrogen for the oxygen present, the <i>total heat +units</i> given by Favre and Silbermann's figures for carbon +(8,080) and hydrogen (34,462) will be 8,746. It will be seen, +therefore, that the calorific power, as determined by Thompson's +apparatus, gives a much lower result when multiplied by 537 than +the heat units calculated from the chemical composition of the +coal. When I used Thompson's apparatus in the chemical laboratory +at Turin to determine the evaporative power of various cargoes of +South Wales coal, it was agreed by mutual consent that the +temperature of the water at starting should be 39° F. (the +temperature at which the <i>heat unit</i> was determined). The +temperature of the room was about 60°, but this varied, as the +weather was somewhat severe and changeable. Under these conditions, +with the water at 39° and room 60°, the coal which gives +14.74 lb. of water per lb. of coal, will give as high as 15.88 lb. +of water per lb. of coal. This result multiplied by 537=8,496 +calories, approaching much more nearly to the theoretic value. This +method of working is still practiced abroad, but experience has +shown that very widely differing results follow when working in +this manner, especially if the temperature of the room is +changeable, as it naturally is where ash determinations and other +chemical work is proceeding simultaneously. The time the experiment +lasts, taking the reading on a quickly rising thermometer and other +considerations, render the experiments anything but trustworthy +when 0.2 of a degree makes a difference of more than 100 calories. +In the instructions supplied with Thompson's calorimeter nothing is +said as to the temperature of the room in which the experiment is +performed, but simply that the water shall be at 60° F. If, +with the water at 60°, a room were at 50°, as it often is +in winter, a good coal would give 14 lb. of water per lb. of coal +as the evaporative power; but if in summer, the room were at +75° and the water at 60°, the same coal would give 15 lb. +of water per lb. of coal. If further evidence were needed of the +effect of temperature consideration of the experiments already +referred to will show how necessary it is that some general rule +shall be adopted. Considerable stress is laid (in the instructions) +upon the quantity of oxygen mixture used being determined by rough +experiments. This I have found leads to erroneous conclusions +unless a number of experiments are tried in the calorimeter, as it +often happens that the quantity which appears to be best adapted is +not that which yields a trustworthy result. There are many samples +of South Wales coal, 30 grains of which will require 10 parts of +oxygen mixture in order to burn completely, but since a little +oxygen is lost in drying and grinding, and few samples of chlorate +are free from chloride, it is not safe to use less than 11 parts of +oxygen mixture, but this amount is sufficient in <i>all</i> cases, +and never need be exceeded. I have made numerous experiments with +various coals (anthracite, steam, semi-bituminous, and bituminous, +including a specimen of the ten yard coal of Derbyshire), and find +that with 11 parts of chlorate and nitrate of potash, they are all +perfectly manageable and yield the best results. It is quite clear +that the excess of chlorate is decomposed in all instances, and the +latent heat of the oxygen evolved, but those coals which are best +to experiment with did not yield results that differed when the +quantity of oxygen mixture was reduced to nearly the limit required +for combustion of the coal. Under these circumstances, therefore, +the constant use of 11 parts of oxygen mixture--a suitable quantity +for all coals exported--would enable operators to obtain similar +figures, and make the test uniform in different hands.</p> + +<p>The following is a brief outline of the method of procedure +recommended: Sample the coal until an average portion passes +through a sieve having 64 meshes to the square inch. Take about 300 +grains (20 grammes) of this and run through a brass wire gauze +having 4,600 meshes to the square inch, taking care that the whole +sample selected is thus treated. One part of nitrate of potash and +3 parts of chlorate of potash (dry) are separately ground in a +mortar, and repeatedly sifted through another wire gauze sieve, +having 1,000 meshes to the square inch, in order that the oxygen +mixture shall <i>not</i> be ground to an impalpable powder, as this +is very undesirable. It absorbs moisture rapidly, and interferes +with the regularity of the combustion when very fine. 330 grains of +the powder are weighed out (after drying), and intimately +incorporated with 30 grains of coal--better with a spatula than by +rubbing in a mortar--and then introduced into a copper cylinder +(3½ inches long by ¾ inch wide, made from a copper +tube), and pressed down in small portions by a test-tube with such +firmness as is required by the nature of the coal, not tapped on +the bottom, since the rougher portions of the oxygen mixture rise +to the surface. As the temperature of a room is almost invariably +much higher than the water supply, a little hot water is added to +that placed in the glass cylinder, until the difference of +temperature between the water and the room is about the mark +indicated in the following table:</p> + +<pre> + Room at The water should be +<br> + 80° F. 70° F. + 72 64 + 67 60 + 60 54 + 55 50 + 50 46 + 42 40 +</pre> + +<p>Say, for example, the room was at 57° and the water placed +in the cylinder was at 46°: add a little hot water and stir +with the thermometer until it assumes 52°. By the time the +excess of water has been removed with a pipette until it is exactly +level with the mark, and all is ready, the temperature will rise +nearly 0.5°. Let the thermometer be immersed in the water at +least three minutes before reading. The fuse should be placed in +the mixture, and everything at hand before reading and removing the +thermometer. After igniting the fuse and immersing the copper +cylinder in the water, the apparatus should be kept in the best +position for the gases to be evolved all around the cylinder, and +the rate of combustion noted. Some coals are very unmanageable +without practice, and samples of "patent fuel" are sometimes met +with, containing unreasonable proportions of pitch, which require +some caution in working and very close packing, inasmuch as small +explosions occur during which a little of the fuel escapes +combustion.</p> + +<p>In order that the experiment shall succeed well, experience has +shown that the nature of the fuse employed has much to do with it. +Plaited or woven wick is not adapted, and will fail absolutely with +dry coals, unless it is made very free burning. In this case not +less than three-quarters of an inch in length is necessary, and the +weight of such is very appreciable. I always use Oxford cotton, and +thoroughly soak it in a moderately strong solution of nitrate of +potash. When dry it should burn a little too fast. The cotton is +rubbed between two pieces of cloth until it burns just freely +enough; then four cotton strands are taken, twisted together, and +cut into lengths of ¾ inch and thoroughly dried. Open out +the fuse at the lower end when placing it in the mixture so as to +expose as much surface as possible in order to get a quick start, +but carefully avoid pressing the material, and use a wire to fill +up close to the fuse. A slow start often spoils the experiment, +through the upper end of the cylinder becoming nearly filled up +with potassic chloride, etc.</p> + +<p>By paying attention to such details, and following the method +recommended, the apparatus yields very satisfactory results with +bituminous and semi-bituminous coals.--<i>Chemical News</i>.</p> + +<hr> +<p><a name="7"></a></p> + +<h2>EXPLOSION AS AN UNKNOWN FIRE HAZARD.</h2> + +<p>Words pass along with meanings which are simple +conventionalities, marking current opinions, knowledge, fancies, +and misjudgments. They attain to new accretions of import as +knowledge advances or opinions change, and they are applied now to +one set of ideas, now to another. Hence there is nothing truer than +the saying, "definitions are never complete." The term explosion in +its original introduction denoted the making of a <i>noise</i>; it +grew to comprehend the idea of <i>force</i> accompanied with +violent outburst; it is advancing to a stage in which it implies +<i>combustion</i> as associated with destruction, yet somewhat +distinct from the abstract idea of the resolution of any form of +matter into its elementary constituents. The term, however, as yet +takes in the idea of combustion as a decomposition in but a very +limited degree, and it may be said to be wavering at the line +between expansion and dissociation.</p> + +<p>Strictly, in insurance, fire and explosion are different +phenomena. A policy insuring against fire-loss does not insure +against loss by explosion. It thereby enforces a distinction which +exists, or did exist, in the popular mind; and fire, in an +insurance sense, as distinct from explosion, was accurately defined +by Justice McIlvaine, of the Supreme Court of Ohio (1872), in the +case of the Union Insurance Company vs. Forte, i.e., an explosion +was a remote cause of loss and not the proximate cause, when the +<i>fire</i> was a burning of a gas jet which did not destroy, +though the explosion caused by the burning gas-jet did destroy. +Earlier than this decision, however (in 1852), Justice Cushing, of +the Supreme Court of Massachusetts, in Scripture <i>vs</i>. Lowell +Mutual Fire Insurance Company, somewhat anticipated later +definition, and pronounced for the liability of the underwriter +where all damage by the explosion involves the ignition and burning +of the agent of explosion. That is, for example, the insurer is +liable for damage caused by an explosion from gunpowder, but not +for an explosion from steam. The Massachusetts Judge did not +conceive any distinction as to fire-loss between the instantaneous +burning of a barrel of gunpowder and the slower burning of a barrel +of sulphur, and insurance fire-loss is not to be interpreted +legally by thermo-dynamics nor thermo chemistry. While the legal +principles are as yet unsettled, the tenor of current decisions may +be summed up as follows: If explosion cause fire, and fire cause +loss, it is a loss by fire as <i>proximate</i> cause; and if fire +cause explosion, and explosion cause loss, it is a loss by fire as +<i>efficient</i> cause. Smoke, an imperfect combustion, damages, in +an insurance sense, as well as flame, which is perfect combustion; +and where there is concurrence of expanding air with expanding +combustion, the law settles on the basis of a common account. It's +all "heat as a mode of motion."</p> + +<p>Explosions are the resultants of elemental gases, vaporization, +comminution, contact of different substances, as well as of the +specifically named explosives. With new processes in manufacture, +involving chemical and mechanical transformations, and other uses +of new substances and new uses of old substances, explosions +increase. The flour-dust of the miller, the starch-dust of the +confectioner, increase in fineness and quantity, and they explode; +so does the hop-dust of the brewer. In 1844, for the first time, +Professors Faraday and Lyell, employed by the British government, +discovered that explosion in bituminous coal mines was the +quickening of the comparatively slow burning of the "fire-damp" by +the almost instantaneous combustion of the fine coal-dust present +in the mines. The flyings of the cotton mill do not explode, but +flame passes through them with a rapidity almost instantaneous, yet +not sufficient to exert the pressure which explodes; the dust of +the wood planer and sawer only as yet makes sudden puffs without +detonating force. Naphtha vapor and benzine vapor are getting into +all places. One of the latest introductions is naphtha extracting +oil from linseed, and then volatilized by steam superheated to +400° F. This combination reminds us, as to effectiveness, of +the combination at the recent Kansas City fire, when cans of +gunpowder and barrels of coal oil both went up together.</p> + +<p>But it is the unsuspected causes of explosion which make the +great trouble, and prominent among these is conflagration as itself +the cause of explosion, and such explosion may develop gases which +are non-supporters of combustion as well as those which are +inflammable. You throw table salt down a blazing chimney to set +free the flame-suppressing hydrochloric acid, you discharge a +loaded gun up a blazing chimney to put out the fire by another +agency; still the salt, with certain combinations, may be +explosive, a resinous vapor may be combustive in a hydrochloric +atmosphere, and gunpowder isn't harmless when thrown upon a +blaze--in fact, our common fire-extinguisher, water, has its +explosive incidences as liquid as well as vapor.</p> + +<p>Gases explosive in association may be set free by the +temperature of a burning building and get together. In respect to +the old conundrum, "Will saltpetre explode?" Mr. A. A. Hayes, Prof. +Silliman, and Dr. Hare's views were, as to the explosions in the +New York fire of 1845, that in a closed building having niter in +one part and shellac or other resinous material in another, the +gaseous oxygen generated from the niter and the carbureted hydrogen +from the resins mingling by degrees would at length constitute an +explosive mixture. A brief consideration of specific explosives +uniting may serve to illustrate this phase of the subject.</p> + +<p>Though the explosion of gunpowder is the result of a chemical +change whereby carbonic acid gas at high tension is evolved (due to +the saltpeter and the charcoal), the effect and rapidity of action +are greatly promoted by the addition of sulphur. On the contrary, +dynamite, now so important, and various similar explosives, are but +mixtures of nitro-glycerine with earthy substances, in order to +diminish and make more manageable the development of the rending +force of the base. The explosive power of any substance is the +pressure it exerts on all parts of the space containing it at the +instant of explosion, and is measured by comparing the heat +disengaged with the volume of gas emitted, and with the rapidity of +chemical action. In the case of gunpowder, the proper manipulation +and division of the grains is important, because favoring +<i>rapid</i> deflagration; but in a purely chemical explosion, each +separate molecule is an explosive, and the reaction passes from the +interior of one to the interior of another, suddenly driving the +atoms much further apart than their naturally infinitesimal +vibrations.</p> + +<p>Purely chemical explosives like nitro-glycerine, gun-cotton, the +picrites, and the fulminates, present a terrible danger from the +unknown mode of the new union of atoms, and reaction of the +particles within themselves, in spontaneous explosions happening in +irregular manner. Some curious circumstances attend the manufacture +and use of gun-cotton,[1] nitro-glycerine, and dynamite. Baron von +Link, in his system of the artillery use of gun-cotton, diminishes +the danger of sudden explosion by twisting the prepared cotton into +cords or weaving it into cloth, thereby securing a more uniform +density. Mr. Abel's mode of making gun-cotton, which explosive is +now used more than any other by the British government, includes +drying the damp prepared cotton upon hot plates, <i>freely open to +the air</i>. If ignited by a flame, however, in an unconfined +place, gun-cotton only burns with a strong blaze, but if +<i>confined</i> where the temperature reaches 340° F., it +explodes with terrific violence. Somewhat similar is the action of +nitro-glycerine and dynamite, which simply <i>burn</i> if ignited +in the open air, while the same substance will <i>explode</i> +through a very slight concussion or by the application of the +electric spark; a red-hot iron, also, if applied, will explode them +when a flame will not. With care, nitro-glycerine can be kept many +years without deterioration; and it has been heated in a sand-bath +to 80° C. for a whole day without explosion or alteration. One +curious experiment is deserving of mention: If a broad-headed nail +be partly driven into pine wood, and then some pieces of dynamite +placed on the head of the nail, the latter may be struck hard blows +with a wooden mallet without exploding the dynamite <i>so long as +the nail will continue to enter the wood</i>.</p> + +<p>[Footnote 1: The purest gun-cotton may be regarded as a +<i>cellulose</i>, in which three atoms of hydrogen are replaced by +three molecules of peroxide of nitrogen.]</p> + +<p>Taking gunpowder as the unit, picrate of potash (picric acid and +potassium) has five times more force, gun-cotton seven and a half +times, and nitro-glycerine ten times more force. There are others +still more powerful, but less known and used, and some explosives +are quite uncontrollable and useless.</p> + +<p>But the particular object of these remarks is to refer to +articles of merchandise non-explosive under general conditions, but +so in particular circumstances, as the two fire-extinguishers, +water and salt, are explosive under given conditions. The memorable +fire which, in July, 1850, destroyed three hundred buildings in +Philadelphia, upon Delaware avenue, Water, Front, and Vine streets, +was largely extended by explosions of possibly concealed or unknown +materials, the presence of the generally recognized explosives +being denied by the owners of the properties.</p> + +<p>"The germ of the first knowledge of an explosive was probably +the accidental discovery, ages ago, of the deflagrating property of +the natural saltpeter <i>when in contact with incandescent +charcoal</i>."[1] Although much manipulation is deemed necessary to +form the close mechanical mixture of the materials of gunpowder, it +has never been proved that such intimate previous union is +necessary to precede the chemical reaction causing explosion; +indeed, some explosions in powder works, before the mixture of the +materials, or just at its commencement, seem to point to the +contrary. It is also certain that in the manufacture of gunpowder +the usual nitrate of potassium (saltpeter) can be replaced by the +nitrates of soda, baryta, and ammonia, also by the chloride of +potassium; charcoal by sawdust, tan, resin, and starch; and though +a substitute for sulphur is not easily found, the latter, or a +similar substance, is not an absolute necessity in the composition +of gunpowder.[2]</p> + +<p>[Footnote 1: Encyclopædia Britannica, new edition, viii, +p. 806.]</p> + +<p>[Footnote 2: <i>Vide</i> Abel's Experiments in Gunpowder, as +detailed in Phil. Trans. Eoy. Soc, 1874.--<i>Vide</i> also <i>Bull. +Soc. d'Encouragement</i>, Nov., 1880, p. 633, <i>Sur les +Explosives</i>.]</p> + +<p>The generally received theory of the chemical action which makes +gunpowder explosive is that it is due to the superior affinity of +the oxygen of the niter (KNO<sub>3</sub>) for the carbon of the +charcoal, and the production of carbonic acid gas (CO<sub>2</sub>) +and carbonic oxide (CO) suddenly and in great volume. The latter +extinguishes flame as well as the former, unless its own +flammability is supported by the oxygen of the atmosphere until the +degree of oxygenation CO<sub>2</sub> is reached. Considering that +water (H<sub>2</sub>O) is composed of two volumes of hydrogen and +one of oxygen, and that under an enormously high temperature and +the excessive affinity of oxygen gas for potassium or sodium (freed +from nitrate union), dissociation of the water may be possible, +aided by its being in the form of spray and steam, we would +hesitate to deny that an explosive union of suitable crude salts +could occur during the burning of a building containing them when +water for extinguishment was put on. Any one who has seen the +brilliance with which potassium and sodium burn upon water can +easily imagine how such strong affinity of oxygen for these +substances might aid in severing its union in water in their +presence and under extraordinary heat. It might be safe so say that +the presence of water under very high temperature may be as aidful +to form an explosive among such salts as have been named, as +sulphur is for the rapid combustion of gunpowder.</p> + +<p>In the review for August, 1862 (Saltpeter Deflagrations in +Burning Buildings and Vessels--Water as an Explosive Agency), it +was shown that Mr. Boyden's experiments in 1861-62 proved that +explosions would occur when water was put upon niter heated alone, +and stronger explosion from niter, drywood, and sulphur; also +explosion when melted niter was poured on water. The following +points we reproduce for comparison: If common salt be heated +separately to a bright heat, and water <i>at</i> 150° F. poured +on it, an explosion will occur. Niter mixed with common salt, +placed upon burning charcoal, and water added, produce a stronger +explosion than salt alone. Heating caustic potash to a white heat, +and adding <i>warm or hot water</i>, produces explosion. At a +Boston fire small explosions were observed upon water touching +culinary salt highly heated. Anthracite coal and niter heated in a +crucible exploded when <i>sea water</i> was poured on them.</p> + +<p>The production of explosion by the putting of water on nitrate +of potassium and chloride of sodium arises from the union, at high +temperature, of the oxygen of the water with the potash and soda. +Of the three liberated gases, hydrogen only is inflammable, and the +other two suffocative of flame; but together the nitrogen and +chlorine are not to be undervalued, for chloride of nitrogen is +ranked as the most terrible and unmanageable of all explosives. +Chlorine is a great water separator, but in the present case its +affinity for hydrogen would result in hydrochloric acid, a fire +extinguisher.</p> + +<p>What happens in chemical experiment may be developed on a large +scale in burning grocery, drug, or drysalters' stores, when great +quantities of materials, such as just mentioned, including common +salt, almost always present, are heated most intensely, and then +subjected to the action of water in heavy dashes, or in form of +spray or steam.</p> + +<p>Picric acid, the nature of which we have several times +previously mentioned, and which explodes at 600° F. (only +28° above gunpowder), may also be an element in such explosions +during fires. Its salts form, in combinations, various powerful +explosives, much exceeding gunpowder in force; and they have been +used to a considerable extent in Europe. Picric acid, now much +employed by manufacturers and dyers for obtaining a yellow color, +is always kept in store largely by drysalters and druggists, and +generally by dyers, but in smaller quantity.</p> + +<p>In a very destructive fire which occurred in Liverpool, Eng., in +October, 1874, involving the loss of several "fire-proof" stores, +repeated explosions of the vapor of turpentine rent ponderous brick +arched vaults, and exposed to the flames stocks of cotton, etc., in +the stories above. This conflagration was started by the +carelessness of an <i>employee</i> in snuffing a tallow candle with +his fingers and throwing the burning snuff into the open bung-hole +of a sample barrel of turpentine, of which liquid there were many +hundreds of barrels on storage in the buildings. Turpentine vapor +united with chlorine gas may not produce explosion, but by +spreading flames almost instantly throughout the burning buildings, +such burnings have practically equaled, if not excelled, +explosions, which may sometimes be fire-extinguishers. In such +cases detonation may be prevented by there being ample space to +receive the suddenly ignited vapor, lessening the tension of it, +but carrying the flames much more rapidly than otherwise to +inflammable materials at great distance.</p> + +<p>If disastrous results have arisen from the vapor of turpentine +as a fire spreader in vaults without windows, it is possible that +if a quantity of hot water were suddenly converted into steam in +closely confined spaces, effects of pressure might be observed, +less destructive perhaps, but resembling those which other +explosives might produce. If the immense temperature attained in +some conflagrations be considered--sufficient to melt iron and +vitrify brick--it is possible to conceive of water as being +instantly converted into steam. Even a very small quantity of water +thus expanded could produce most disastrous results. While such +formation of steam, if it happened, would certainly extinguish most +flames in direct contact, the general phenomena shown would be +explosive.</p> + +<p>A curious circumstance occurred at the Broad street (N.Y.) fire +in 1845, previously mentioned. The fire extended through to +Broadway, and almost to Bowling Green. A shock like a dull +explosion was heard, and by many this was attributed to the effects +of gunpowder and saltpeter. Several firemen were, at the moment of +the shock, on the roof of the burning building, when the whole roof +was suddenly raised and then let down into the street, carrying the +men with it uninjured. One of the firemen described the sensation +"as if the roof had been first <i>hoisted</i> up and then squashed +down." <i>Query:</i> Was this like the common lifting and falling +back of the loose lid of a tea-kettle containing boiling water? Was +it from steam--at a low pressure perhaps--seeking vent through the +roof in like manner to the raising of the kettle-lid? Without +dilating on this part of the subject, we mention it as a possible +cause of minor explosions--doubtless to become better known in +future. It may even be that explosions happening from steam acting +in close spaces may have been attributed to gunpowder, or to niter +and other salts, separate, but suddenly caused to combine in +chemical reaction.--<i>American Exchange and Review.</i></p> + +<hr> +<p><a name="8"></a></p> + +<h2>CARBON.--SYMBOL C.--COMBINING WEIGHT 12.</h2> + +<h3>By T.A. POOLEY, B.Sc., F.C.S.</h3> + +<p>This element, which next deserves our attention, is one of great +importance and wide distribution; it occurs in nature in both the +free and the combined states, and the number of compounds which it +forms with other elements is very large. Unlike the previous +elementary bodies we have studied, carbon is only known to us in +the solid form when free, although many of its combinations are +gaseous at the ordinary temperature and pressure. Carbon is known +to exist in several different physical states, thus illustrating +what chemists call <i>allotropism</i>, which means that substances +of identical chemical composition sometimes possess altogether +different outward and physical appearances. Thus the three states +in which pure carbon exists, viz., diamond, graphite, or plumbago, +and charcoal are as different as possible, and yet chemically they +are all exactly the same substance. The diamond is the purest +carbon, and occurs in the crystalline form known as a regular +octahedron; the diamond is one of the hardest substances known, and +is therefore, utilized for cutting glass; it has also a very high +specific gravity, namely, 3.5, which means that it is three and a +half times heavier than water, and it is far heavier than any of +the other allotropic modifications of carbon. Graphite or plumbago, +the second form in which carbon occurs, is widely distributed in +nature, and the finer qualities are known as black lead, although +no lead enters into their composition, as they are composed of +carbon almost as pure as the diamond; the specific gravity of +graphite is only 2.3. Charcoal, the third allotropic modification +of carbon, is by far the most common, and is formed by the natural +or artificial disintegration of organic matters by heat; we thus +have formed wood charcoal, animal charcoal, lamp-black, and coke, +all produced by artificial means, and we may also class with these +coal, which is a natural product, and which contains from 85 to 95 +per cent. of pure carbon.</p> + +<p>Wood charcoal is made by heating wood in closed vessels or in +large masses, when all the hydrogen, oxygen, and nitrogen are +expelled in the gaseous state, and the carbon is left mixed with +the mineral constituents of the wood; this form of carbon is very +porous and light, and is used in a number of industrial +processes.</p> + +<p>Animal charcoal, as its name implies, is the carbonaceous +residue left on heating any animal matters in a retort; and +contains, in addition to the carbon, a large proportion of +phosphates and other mineral salts, which, however, can be +extracted by dilute acids. Animal charcoal possesses to a +remarkable degree the property of removing color from solutions of +animal and vegetable substances, and it is used for this purpose to +a large extent by sugar refiners, who thus decolorize their dark +brown sirups; in the manufacture of glucose and saccharums for +brewers' use, the concentrated solutions have to be filtered +through layers of animal charcoal in order that the resulting +product may be freed from color. The decolorizing power of animal +charcoal can be easily tested by any brewer, by causing a little +dark colored wort to filter through a layer of this material; after +passing through once or twice, the color will entirely disappear, +or at all events be greatly reduced in intensity. Animal charcoal +also absorbs gases with great avidity, and on this account it is +utilized as a powerful disinfectant, for when once putrefactive +gases are absorbed by it, they undergo a gradual oxidation, and are +rendered innocuous, in the same way animal charcoal is a valuable +agent for purifying water, for by filtering the most impure water +through a bed of animal charcoal nearly the whole of the organic +impurities will be completely removed.</p> + +<p>Lamp-black is the name given to those varieties of carbon which +are deposited when hydrocarbons are burned with an insufficient +supply of oxygen; thus the smoke and soot emitted into our +atmosphere from our furnaces and fireplaces are composed of +comparatively pure carbon.</p> + +<p>Coal is an impure form of carbon derived from the gradual +oxidation and destruction of vegetable matters by natural causes; +thus wood first changes into a peaty substance, and subsequently +into a body called lignite, which again in its turn becomes +converted into the different varieties of coal; these changes, +which have resulted in the accumulation of vast beds of coal in the +crust of the earth, have been going on for ages. There are very +many different kinds of coal; some are rich in hydrogen, and are +therefore well adapted for making illuminating gas, while others, +such as anthracite, are very rich in carbon, and contain but little +hydrogen; the last named variety of coal is smokeless, and is +therefore largely used for drying malt.</p> + +<p>Carbon occurs in nature also in a combined state; limestone, +chalk, and marble contain 12 per cent. of this element. It is also +present in the atmosphere in the form of carbonic acid, and the +same compound of carbon is present in well and river waters, both +in the free state and combined with lime and magnesia. All animal +and vegetable organisms contain a large proportion of carbon as an +essential constituent; albumen contains about 53 per cent., alcohol +contains 52 per cent., starch 44 per cent., cane sugar 42 per +cent., and so on. The presence of carbon in the large class of +bodies known to chemists as carbohydrates, of which starch and +sugar are prominent examples, can be easily demonstrated. If a +little strong sulphuric acid be added to some powdered cane sugar +in a glass, the mass will soon begin to darken in color and swell +up, and in the course of a few minutes a mass of black porous +carbon will separate, which can be purified from the acid by +repeated washings; the sugar is composed of carbon, hydrogen, and +oxygen, the two last-named elements being present in the exact +proportion necessary to form water; the sulphuric acid having a +strong affinity for water, removes the hydrogen and oxygen, and the +carbon is then left in a free state.</p> + +<p>Carbon forms two compounds with oxygen--carbon monoxide, +commonly called carbonic oxide, and carbon dioxide, commonly called +carbonic acid; and the last-named, being of most importance, will +be studied first.</p> + +<p><i>Carbon Dioxide, or Carbonic Acid, Symbol +CO<sub>2</sub></i>.--Carbonic acid occurs, as we have already +stated, in large quantities in combination with lime and magnesia, +forming immense rock formations of limestone, chalk, marble, +dolomite, etc.; it also issues in a gaseous state from volcanoes, +and it is always present in small quantities in the atmosphere; it +is found dissolved in well and river waters, and it is a product of +the respiration of animals. Brewers also are well aware of the +existence of this body, for it is evolved in enormous quantities +during the alcoholic fermentation of saccharine fluids. When +carbonaceous substances are burnt the bulk of the carbon is +converted into carbonic acid, and thus our furnaces and fireplaces +are continually emitting enormous quantities of carbonic acid into +the atmosphere. With these different sources of supply it might +reasonably be thought that carbonic acid would be gradually +accumulating in our atmosphere; the breathing of animals, the +eruption of volcanoes, the combustion of fuel, and the fermentation +of sugar, are ever going on, and to a fast-increasing extent with +the progress of civilization, and yet the proportion of carbonic +acid in our atmosphere is no greater now than it was at the +earliest time when exact chemical research determined its presence +and quantity. A counteracting influence is always at work; nature +has beautifully provided for this by causing plants to absorb +carbonic acid, holding some of the carbon, and allowing the oxygen +to escape again into the atmosphere to restore the equilibrium of +purity. This mutual evolution and absorption of carbonic acid is +continually going on; occasionally there may be either an excess or +a deficiency in a particular place, but fortunately any +irregularity in this respect is soon overcome, and the air retains +its original composition, otherwise animal life on the face of the +globe would be doomed to gradual but sure extinction.</p> + +<p>Carbonic acid can be prepared for experimental purposes by +causing dilute hydrochloric acid to act upon fragments of marble +placed in a bottle with two necks, into one neck of which a funnel +passing through a cork is fixed, and into the other a bent tube for +conveying the gas into any suitable receiver. The evolution of +carbonic acid by this method is rapid, but easily regulated, and +the gas may be purified by causing it to pass through some water +contained in another two-necked bottle, similar to the generator. +The chemical change involved in this decomposition is expressed by +the following equation:</p> + +<pre> + CaCO_3 + 2HCl = CO_2 + H_2O + CaCl_2 + Calcium Hydrochloric Carbonic Water. Calcium +Carbonate. Acid. Acid. Chloride. +</pre> + +<p>By referring to the table of combining weights given in a +previous paper, it will be seen that 100 parts of calcium carbonate +will yield 44 parts of carbonic acid. Instead of hydrochloric acid +any other acid may be used, and in the practical manufacture of +carbonic acid for aerated waters sulphuric acid is the one usually +employed. Carbonic acid is colorless and inodorous, but has a +peculiar sharp taste; it is half as heavy again as air, its exact +specific gravity being 1529; one hundred cubic inches weigh 47.26 +grains. It is uninflammable, and does not support combustion or +animal respiration. Under a pressure of about 38 atmospheres, at a +temperature of 32° F., carbonic acid condenses into a colorless +liquid, which may also be frozen into a compact mass resembling +ice, or into a white powder like snow. Carbonic acid is soluble in +water, and at the ordinary pressure and temperature one volume of +water will hold in solution one volume of the gas; under increased +pressures, far larger quantities of the gas can be held in +solution, but this is rapidly evolved as soon as the excess of +pressure is removed. Upon this property the manufacture of aerated +waters depends. The presence of free carbonic acid can be easily +detected by causing the gas to pass over the surface of some clear +lime-water. If any be present a white film of carbonate of lime +will at once be formed. In testing carbonic acid in a state of +combination, the gas must first be liberated by acting upon the +substance with a stronger acid, and then applying the lime-water +test. The presence of large quantities of carbonic acid in a +gaseous mixture can be readily detected by plunging into the vessel +a lighted taper, which will be immediately extinguished. This ought +always to be adopted in a brewery, where many fatal accidents have +happened through workmen going down into empty fermenting vats and +wells without first taking this precaution.</p> + +<p>The presence of carbon in this colorless gas can be demonstrated +by causing some of it to pass over a piece of the metal potassium +placed in a hard glass tube, and heated to dull redness; the +potassium then eagerly combines with the oxygen, forming oxide of +potassium, and the carbon is liberated and can be separated in the +form of a black powder by washing the tube out with water.</p> + +<p><i>Carbon Monoxide, or Carbonic Oxide. Symbol CO.</i>--This is +formed when carbon is burnt with an insufficient supply of oxygen, +or when carbonic acid gas is passed over some carbon heated to +redness. This gas is continually being formed in our furnaces and +fire-places; at the lower part of the furnace, where the air +enters, the carbon is converted into carbonic acid, which in its +turn has to pass through some red-hot coals, so that before +reaching the surface it is again converted into carbonic oxide; +over the surface of the fire this carbonic oxide meets with a fresh +supply of oxygen, and is then again converted into carbonic acid. +The peculiar blue lambent flame often observed on the surface of +our open fire-places is due to the combustion of carbonic oxide, +which has been formed in the way we have just described. Carbonic +oxide is a colorless, tasteless gas, which differs from carbonic +acid by being combustible, and by not having any action on lime +water.--<i>Brewers' Guardian.</i></p> + +<hr> +<p><a name="21"></a></p> + +<h2>SEYFFERTH'S PYROMETER.</h2> + +<p>The thermometers and pyrometers usually employed are almost all +based on the expansion of some fluid or other, or upon that of +different metals. The first can only be constructed with glass +tubes, thus rendering them fragile. The second are often wanting in +exactness, because of the change that the molecules of a solid body +undergo through heat, thus preventing them from returning to +exactly their first position on cooling.</p> + +<p class="ctr"><img src="images/4a.png" alt= +"Fig. 1.--Pyrometer with Electric Indicator."></p> + +<p class="ctr">Fig. 1.--Pyrometer with Electric Indicator.</p> + +<p>The principle of the Seyfferth pyrometer is based on the fact +that the pressure of saturated vapors, that is, vapors which remain +in communication with the liquid which has produced them, preserves +a constant ratio with the temperature of such liquid, while, on the +other hand, the temperature of the latter when shut up in a vessel +will correspond exactly with that of the medium into which it is +introduced.</p> + +<p class="ctr"><img src="images/4b.png" alt=""></p> + +<p class="ctr">Fig. 2.--Method of Mounting by means of a<br> +cone on vacuum apparatus.</p> + +<p class="ctr"><img src="images/4c.png" alt= +"Fig. 3.--Mounting by means of a sleeve on vacuum apparatus."></p> + +<p class="ctr">Fig. 3.--Mounting by means of a sleeve on vacuum +apparatus.</p> + +<p>This instrument is composed of a metallic vessel or tube which +contains the liquid to be exposed to heat, and of a spring +manometric apparatus communicating with the tube, and by means of +which the existing temperature is shown. The dial may be provided +with index needles to show minimum and maximum temperatures, as +well as be connected with electric bells (Fig. 1) giving one or +more signals at maximum and minimum temperatures. The vessel to +contain the liquid may be of any form whatever, but it is usually +made in the shape of a straight or a bent tube. The nature of the +metal of which the latter is made is subordinate, not only to the +maximum temperature to which the apparatus are to be exposed, but +also to the nature of the liquid employed. It is of either yellow +metal or iron. To prevent oxidation of the tube, when iron is +employed, it is inclosed within another iron tube and the space +between the two is filled in with lead. When the apparatus is +exposed to a high temperature the lead melts and prevents the air +from reaching the inner tube, so that no oxidation can take +place.</p> + +<p><i>Pyrometers filled with Ether.</i>-These are tubular, and +constructed of yellow metal, and are graduated from 35° C. to +120°. They are used for obtaining temperatures in vacuum +apparatus, cooking apparatus, diffusion apparatus, saturators, etc. +Figs. 2, 3, 4, and 5, show the different modes of mounting the +apparatus according to the purpose for which it is designed.</p> + +<p><i>Pyrometers filled with distilled water</i> are used for +ascertaining temperatures ranging from 100° to 265° C., +80° to 210° R., or 212° to 510° F.</p> + +<p><i>Pyrometers filled with mercury</i> are constructed for +ascertaining temperatures from 360° to 750° C.</p> + +<p class="ctr"><img src="images/4d.png" alt=""></p> + +<p class="ctr">Fig. 4.--Mounting on horizontal pipes by<br> +thread on the tube.</p> + +<p class="ctr"><img src="images/4e.png" alt=""></p> + +<p class="ctr">Fig. 5.--Mounting by means of a clasp<br> +in reservoirs.</p> + +<h3>APPLICATION OF THE PYROMETER IN BONE BLACK FURNACES.</h3> + +<p>The temperature necessary for the complete carbonization of the +organic substances of animal charcoal is from 430° to 500° +C. In order to transmit this temperature from the cylinder to the +charcoal it is indispensable that the air surrounding the cylinder +be heated to 480° to 550°. If the heating of the animal +black exceeds 500° the product hardens, diminishes in volume, +and loses its porosity. There are two methods of ascertaining the +temperature of the red-hot bone black by means of the pyrometer: +First, by inserting the tube of the instrument into the black. +(Fig. 6, a.) Second, by finding the temperature of the hot gases in +the furnaces (Fig. 6, b.). In the first case, the plunge tube +should be of sufficient length to allow its extremity to penetrate +to the very bottom layer of the red-hot black. This mode of direct +control of the temperature of the black is only employed for +ascertaining the work accomplished by the furnace, that is to say, +the ratio existing between the temperature of the hot air +surrounding the cylinder and the black itself. This calculation +being effected, it is useless to note the differences of +temperature which arise in the spaces between the cylinders of +which the furnace is composed.</p> + +<p>The position that the pyrometer should occupy is subordinate to +the construction of the furnace. Fig. 6 shows the type which is +most employed.</p> + +<p class="ctr"><img src="images/4f.png" alt= +"Fig. 6.--The Pyrometer mounted on a bone-black furnace."></p> + +<p class="ctr">Fig. 6.--The Pyrometer mounted on a bone-black +furnace.</p> + +<p>In a furnace with lateral fire-place, cc are the heating +cylinders, and dd the cooling cylinders. C D is the plate on which +are mounted vertically the former, and from which are suspended the +latter, b shows the pyrometer, the length of which must be such +that the manometric apparatus shall stand out one or two inches +from the external surface of the wall, while its tube, traversing +the wall, shall reach the very last row of heating cylinders.</p> + +<p>That the apparatus may form a permanent regulator for the stoker +it is well to adapt to it an arrangement permitting of a graphic +control of the work accomplished and signaling by means of an +electric bell when the temperature of the gases in the furnace +descends below 480° C. or rises above 550° C.</p> + +<h3>APPLICATION OF THE APPARATUS TO BRICK FURNACES AND IN THE +MANUFACTURE OF CHEMICAL PRODUCTS.</h3> + +<p>The operation of heating brick furnaces is generally performed +according to empirical methods, the temperature having to vary much +according to the products that it is desired to obtain. It is +necessary, however, for a like product to maintain as uniform a +temperature as possible. These observations are particularly +applicable to continuous furnaces such as annular brick furnaces, +etc., in which a uniformity of temperature in the different +chambers is of vital importance to perfect the baking. In these +furnaces the tube of the pyrometer is inserted through one of the +apertures at the top, as shown in Fig. 7. The dial is graduated up +to 750°, which is more than sufficient, since the temperature +of the upper part of a compartment fully exposed to the heat rarely +exceeds 670° to 680° C.</p> + +<p class="ctr"><img src="images/4g.png" alt= +"Fig. 7.--The Pyrometer mounted on a brick furnace."></p> + +<p class="ctr">Fig. 7.--The Pyrometer mounted on a brick +furnace.</p> + +<hr> +<p><a name="9"></a></p> + +<h2>MANUFACTURERS' SOAPS AND THEIR PRODUCTION.</h2> + +<h3>By W. J. MENZIES.</h3> + +<p>Potash soaps are generally superior to soda soaps for most +purposes, but more especially in washing wool and woolen goods. The +difference between the use of a potash and a soda soap for these +purposes is very marked. Potash lubricates the fiber of the wool, +renders it soft and silky, and to a certain extent bleaches it; +soda, on the other hand, has a tendency to turn wool a yellow +color, and renders the fiber hard and brittle. It cannot be too +strongly insisted upon, therefore, that nothing but a potash soap +(or some form of potash in preference to soda if an alkali alone is +employed) should be used in washing wool in any form--either +manufactured or unmanufactured. This is fully borne out by nature, +who invariably assimilates the most appropriate substances. Wool +when growing in its natural state is lubricated and protected by a +sticky substance called "grease" or "suinte;" this consists to the +extent of nearly half its weight of carbonate of potash, hardly a +trace of soda being present. It is very evident, therefore, that +potash must be more suitable for washing wool than soda, as the +teaching of nature is always correct.</p> + +<p>There are certain prejudices against the use of potash soap, +which have, to a great extent, prevented its more extensive use. +Many consumers of soap fancy that because a potash soap is soft it +necessarily must contain more water than a soda soap; this, +however, is quite an erroneous notion. A potash soap is soft, +because it is the nature of all potash soaps to be so, just in the +same way that on the other hand all soda soaps are hard. As an +actual fact a good potash soap contains less water than many quite +hard soda soaps that are now in the market. Another reason is that +soapmakers have had every interest in using soda in preference to +potash--particularly when latterly soda has been so cheap.</p> + +<p>Potash not only is a more expensive alkali, but its combining +equivalent is greatly against it as compared with soda; that is to +say, that thirty-one parts of actual or anhydrous soda will +saponify as much tallow or oil as forty-seven parts of anhydrous +potash. It will be evident, therefore, that the use of potash +instead of soda is decidedly more advantageous to the soapboiler, +and more particularly in the present age, when the demand is for +cheap articles, often quite without regard to the quality or +purpose for which they are to be used. As far as consumers are +concerned, this has been a mistake. Potash soap, though it may cost +more, is in most cases actually the most economical. Soap is never +used in exact chemical equivalents, but an excess is always taken. +Potash soap is much more soluble than a soda soap; it therefore +penetrates the fiber, and consequently removes dirt and grease much +more quickly. Notwithstanding, also, that its chemical combining +equivalent is greater than that of soda, it is, nevertheless, the +strongest base, and always combines with any substance in +preference to soda. For these reasons--probably combined also with +the fact that in the whole realm of the animal and vegetable +kingdoms, to which all textile fabrics belong, potash is more +naturally assimilated than soda--a smaller quantity of potash soap +will do more practical work than a larger quantity of soda +soap.</p> + +<p>There are other reasons why potash soaps have not been used; +originally soft soap was made either with fish oil or olive oil. +Fish oil is objectionable, as the strong smell imparted to the soap +renders it unfit for many finishing purposes. Nothing can be better +than olive oil soap, but it is a costly article, and only can be +used for finer purposes. There are now, however, many of the seed +oils that are much cheaper. Linseed, rape seed, and cotton seed all +produce a good soap. Cotton seed oil is particularly suitable for +the purpose; the manufacture of this oil during the last few years +has been brought to great perfection, and the cost is now much less +than that of tallow or of any other seed oil. It is now difficult +to distinguish a well refined cotton seed oil from olive oil; it is +therefore in every way suitable for making soft soap. One of the +chief causes, however, why potash soap has not been more generally +made is that a convenient form of potash has been unobtainable. For +many years the only source of potash was from the ashes of burnt +trees. These ashes are collected, mixed with lime, lixiviated, and +the resulting lye boiled down. The result is a very impure form of +potash, also of a very variable composition, depending upon the +trees used for the purpose. Canada has been the principal source of +supply of this form of potash; hence the commercial name of +Montreal potashes. The classification of "firsts," "seconds," and +"thirds" is from the inspection at the warehouse there; this, +however, is exceedingly superficial, the ashes being simply tested +for their <i>alkaline</i> strength, with no discrimination between +potash and soda, which is a difficult and delicate chemical test. +Soda being now far cheaper than potash, and also the alkaline +equivalent, as previously explained, being greatly in favor of +soda, there has been every inducement to "enterprising" producers +of ashes to adulterate them with soda, which, in many cases, has +been largely done. Another source of potash has been beetroot +ashes, very similar to wood ashes, and also German carbonate of +potash, which latter about corresponds to a common soda ash, as +compared with caustic soda; with these articles, a tedious boiling +process, very similar to the old process for the production of hard +soap, had to be adopted, the ashes, or carbonate of potash, +previously being dissolved and causticized with lime by the soap +maker. The production of a first-class soft soap was also a very +difficult operation, as the impurities and soda contained varied +considerably, often causing the "boil" to go wrong and give +considerable trouble to the soapboiler.</p> + +<p>During the last two years, however, caustic potash has been +introduced, that manufactured by the Greenbank Alkali Co., of St. +Helens, being very nearly pure. With this article there is no +difficulty in producing a pure potash soap, either for wool +scouring, fulling, or sizing, by a cold process very similar to +that described for the production of hard soda soap with pure +powdered caustic soda.</p> + +<p>The following directions will produce an excellent soap for wool +scouring: Fifty pounds of Greenbank pure caustic potash are put +into eight gallons of soft water; the potash dissolves immediately, +heating the water. This lye is allowed to cool, and then slowly +added, with continual mixing, to 20 gallons of cotton seed oil, +mixed with 20 pounds of melted tallow, the whole being brought to a +temperature of about 90° F. After stirring for some minutes, so +as to completely combine the lye and oil, the mixture is left for +two days in a warm place, when a slow and gradual saponification of +the mass takes place. If when examined the oil and lye are then +found not completely combined, the stiff soap is again stirred and +left two days, when the saponification will be found complete, the +result being the formation of about 330 pounds of very stiff potash +soap, each pound being equal to about two pounds of the ordinary +"fig" soap sold. The requisite quantity is thrown into the scouring +vat with about five per cent of its weight of refined pearl ash to +increase the alkali present, the weight depending somewhat upon the +kind of wool washed on purpose for which the soap is required. If +the wool is very dirty or greasy, rather a stronger soap is +sometimes advisable. This can easily be attained by reducing the +quantity of oil used to 18 gallons.</p> + +<p>The advantages to be gained by the wool scourer or other +consumer making his own potash soap are that a pure, uniform +article can always be thus produced at a less cost than that at +which the soap can be bought. Potash soap, like soda soap now sold, +is much adulterated, in addition to all the impurities originally +contained in the potash used, and which, unlike soda soap, cannot +be separated by any salting process. Many other adulterations are +added to increase the weight and cheapen the cost. Silicate of +potash, resin, and potato flour are all more or less employed for +this purpose, to the gain of the soap maker and at the expense of +the consumer.</p> + +<p>The production of potash soap for fulling and sizing, and the +most suitable oils and tallow for the production of the various +qualities required for these purposes, must be reserved for the +next issue.--<i>Textile Manufacturer.</i></p> + +<hr> +<p><a name="10"></a></p> + +<h2>THE PREPARATION OF PERFUME POMADES.</h2> + +<p>We have, on a previous occasion, described the process of +"maceration" or "enfleurage," that is, the impregnation of purified +fat with the aroma of certain scented flowers which do not yield +any essential oil in paying quantities. At present we wish to +describe an apparatus which is used in several large establishments +in Europe for obtaining such products on the large scale and within +as short a time as possible. The drawing gives the idea of the +general arrangement of the parts rather than the actual appearance +of a working apparatus, for the latter will have to vary according +to the conveniences and interior arrangements of the +factory.[1]</p> + +<p>[Footnote 1: Our illustration has been taken from C. Hofmann, +"Chemisch-technisches Universal-Receptbuch," 8vo, Berlin, 1879, p. +207.]</p> + +<p>A series of frames with wire-sieve bottoms are charged with a +layer of fat in form of fine curly threads, obtained by pressing or +rubbing the fat through a finely-perforated sieve. The frames are +then placed one on top of the other, and to make the connection +between them air-tight, pressed together in a screw press. A +reservoir, E, is charged with a suitable quantity of the flowers, +etc., and tightly closed with the cover, after which the bellows +are set into motion by any power most convenient. Scented air is +thereby drawn from the reservoir, E, through the pipe, G B, toward +the stack of frames containing the finely divided fat, which latter +absorbs the aroma, while the nearly deodorized air is sent back to +the reservoir by the pipe, D, to be freshly charged and again sent +on its circuit. This apparatus is said to facilitate the turning +out of nearly twenty times the amount of pomade for the same number +of frames and the same time, as the old process of "enfleurage." It +might be called the "ensoufflage" process.--<i>New +Remedies.</i></p> + +<p class="ctr"><img src="images/5a.png" alt= +""ENSOUFFLAGE" APPARATUS FOR PERFUMES."></p> + +<p class="ctr">"ENSOUFFLAGE" APPARATUS FOR PERFUMES.</p> + +<hr> +<p><a name="11"></a></p> + +<h2>ORGANIC MATTER IN SEA-WATER.</h2> + +<p>At a recent meeting of the London Chemical Society, Mr. W. Jago +read a paper "On the Organic Matter in Sea-water." On p. 133 of the +"Sixth Report of the Rivers Commission," it is stated that the +proportion of organic elements in sea-water varies between such +wide limits in different samples as to suggest that much of the +organic matter consists of living organisms, so minute and +gelatinous as to pass readily through the best filters. At the +suggestion of Dr. Frankland, the author has investigated this +subject. The water was collected in mid-channel between Newhaven +and Dieppe by the engineers of the London, Brighton, and South +Coast Railway in stoppered glass carboys. The author has used the +combustion method, the albuminoid ammonia, and in some cases the +oxygen process of Prof. Tidy. To determine how the various methods +of water-analysis were effected by a change of the organic matter +from organic compounds in solution to organisms in suspension, some +experiments were made with hay-infusion. The results confirm those +of Kingzett (<i>Chem. Soc. Journ</i>., 1880, 15). the oxygen +required first rising and then diminishing. The author concludes +that the organic matter of sea-water is much more capable of +resisting oxidizing agents than that present in ordinary fresh +waters, and that the organic matter in sea-water is probably +organized and alive.</p> + +<hr> +<p><a name="12"></a></p> + +<h2>BACTERIA LIFE.</h2> + +<p>W. M. Hamlet, in a paper before the London Chemical Society, +said: Flasks similar to those of Pasteur ("Etudes sur la Biere," p. +81), holding about ¼ liter, were used. The liquids employed +were Pasteur's fluid with sugar, beef-tea, hay infusion, urine, +brewers' wort, and extract of meat. Each flask was about half +filled, and boiled for ten minutes, whereby all previously existing +life was destroyed. The flask was then allowed to cool, the +entering air being filtered through a plug of glass wool or +asbestos. The flask was then inoculated with a small quantity of +previously cultivated hay solution or Pasteur's fluid. Hydrogen, +oxygen, carbonic oxide, marsh-gas, nitrogen, and sulphureted +hydrogen, were without effect on the bacteria. Chlorine and hydric +peroxide (about 7 per cent, of a 5 vol. solution) were fatal to +bacteria. The action of various salts and organic acids in 5 per +cent, solution was tried. Many, including potash, soda, potassic +bisulphite, sodic hyposulphite, potassic chlorate, potassic +permanganate, oxalic acid, acetic acid, glycerin, laudanum, and +alcohol, were without effect on the bacterial life. Others--the +alums, ferrous sulphate, ferric chloride, magnesic and aluminic +chlorides, bleaching powder, camphor, salicylic acid, chloroform, +creosote, and carbolic acid--decidedly arrested the development of +bacteria. The author has made a more extended examination of the +action of chloroform, especially as regards the statement of +Müntz, that bacteria cannot exist in the presence of 2½ +per cent, of chloroform, which substance is therefore useful in +distinguishing physiological from chemical ferments. The author +concludes that amounts of chloroform, phenol, and creosote, varying +from ¼ to 3 per cent., do not destroy bacteria, although +their functional activity is decidedly arrested while in contact +with these reagents. To use the author's words, bacteria may be +pickled in creosote and carbolic acid without being deprived of +their vitality. The author concludes that the substances which +destroy bacteria are those which are capable of exerting an +immediate and powerful oxidizing action, and that it is active +oxygen, whether from the action of chlorine, ozone, or peroxide of +hydrogen, which must be regarded as the greatest known enemy to +bacteria.</p> + +<p>Mr. Hamlet, in replying to some remarks of Messrs. Kingzett and +Williams, said that in all cases the solution which he had used had +been completely sterilized by exposure to a temperature of 105° +for ten minutes. The India-rubber tubing he had used was steamed. +Carbolic acid solution must contain at least 5 per cent, of +carbolic acid to be fatal to bacteria. He was quite aware of the +importance of distinguishing between the action of the substances +on various kinds of bacteria, and was quite prepared to admit that +a treatment which would be fatal to one kind of bacterium might not +injure another.</p> + +<hr> +<p><a name="13"></a></p> + +<h2>ON THE COMPOSITION OF ELEPHANTS' MILK.</h2> + +<p>[Footnote: Read before the American Chemical Society, June +3,1881.]</p> + +<h3>By CHAS. A. DOREMUS, M.D., Ph.D.</h3> + +<p>Noticing the recent advertisements in the city regarding the +"Baby Elephant," it occurred to me that perhaps no analysis of the +milk of this species of the mammalia had been recorded. This I +found corroborated, for though the milk of many animals had been +subjected to analysis, no opportunity had ever presented itself to +obtain elephants' milk.</p> + +<p>Through the courtesy of Jas. A. Bailey I was enabled to procure +samples of the milk on several occasions.</p> + +<p>On March 10, 1880, the elephant Hebe gave birth to the female +calf America. Hebe is now twenty eight years old, and the father of +the calf, Mandrie, thirty-two. Since the birth of the "Baby," the +mother has been in excellent health, except during about ten days, +when she suffered from a slight indisposition, which soon left +her.</p> + +<p>When born the calf weighed 213½ lbs., and in April, 1881, +weighed 900 lbs. A very fair year's growth on a milk diet. At the +time I procured the samples both mother and calf were in fine +health.</p> + +<p>To obtain the milk was a matter of some difficulty. The calf was +constantly sucking, nursing two or three times an hour, morning, +noon, and night. The milk could be drawn from either of the two +teats, but only in small quantity. The mother gave the fluid freely +enough, apparently, to her infant, but sparingly to inquisitive +man, so the ruse had to be resorted to of milking one teat while +the calf was at the other.</p> + +<p>When I first examined the specimens they seemed watery, but to +my surprise, on allowing the milk to stand, I could not help +wondering at the large percentage of cream.</p> + +<p>The following represents approximately the daily diet of the +mother:</p> + +<p>Three pecks of oats, one bucket bran mash, five or six loaves of +bread, half a bushel of roots (potatoes, etc.), fifty to +seventy-five pounds of hay, and forty gallons of water.</p> + +<p>Elephants eat continually, little at a time, to be sure, but are +constantly picking. This habit is also observable in the way the +calf nurses. The first specimen of milk was procured on the morning +of April 5, the second on the 9th, and the third on the 10th.</p> + +<p>The last exceeded the others in quantity, and is therefore the +fairest of the three. It took several milkings to get even these, +for the calf would begin to nurse, then stop, and when she stopped +the flow of milk did also.</p> + +<p>I was assured by Mr. Cross and the keeper, Mr. Copeland, that +the milk I obtained had all the appearances of that drawn at +various times since the birth of the calf. Mr. Cross, when in +Boston, compared the milk with that from an Alderney cow, and found +the volume of cream greater.</p> + +<p>I endeavored to have the calf kept away from the mother for some +hours, but could not, since she is allowed her freedom, as she +worries under restraint, and besides, has never been taken from the +mother. The calf picked at oats and hay, but was dependent on the +mother for nourishment.</p> + +<p>It would have been a matter of great satisfaction to me had I +been able to obtain a larger quantity of the milk, or to have +gained even an approximate knowledge of the daily yield, but was +obliged to content myself with what I could get. By comparing +several samples, however, a just conclusion regarding the quality +was found. The analyses of the samples gave the following +results:</p> + +<pre> +<br> + No. I. II. III. + April 5, April 9, April 10, + Morning. Noon. Morning. +<br> + Quantity, 19 cc. 36 cc. 72 cc. + Cream, 52-4, vol.% 58 62 + Reaction, Neutral. Slightly alkaline. Slightly acid. + Sp.gr., ---- ---- 1023.7 +<br> + In 100 parts by weight. + Water............67.567 69.286 66.697 + Solids...........32.433 30.714 33.303 + Fat..............17.546 19.095 22.070 + Solids not fat...14.887 11.619 11.233 + Casein...........14.236 3.694 3.212 + Sugar............14.236 7.267 7.392 + Ash.............. 0.651 0.658 0.629 +<br> +</pre> + +<p>Ten grammes were taken for analysis, and in No. III. duplicates +were made.</p> + +<p>It is evident from these analyses that the milk approaches the +composition of cream, yet it did not have the consistency of +ordinary cream--as cream even rose upon it. Under the microscope +the globules presented a very perfect outline, and were beautifully +even in size and very transparent.</p> + +<p>The cream rose quickly, leaving a layer of bluish tinge below. +The milk was pleasant in flavor and odor, and very superior in +these respects to that of many animals such as goats or camels, and +in quality equal to that of cows. Nor did the milk emit any rank +odor on heating.</p> + +<p>When ten grammes were evaporated to dryness, the last portions +of water were hard to remove, as the residue fairly floated with +oil. Only by long-continued application of heat, and in analysis +III. over sulphuric acid in vacuo, could a constant weight be +obtained.</p> + +<p>I would have used sand in the drying, or Baumhauer's method of +fat extraction, but for the small quantity of milk at my disposal +and from fear of loss of fat in the latter case.</p> + +<p>The fat in III. was determined by extracting the dried residue +and also with 20 c. c. of milk by adding alkali and shaking with +ether, removing and evaporating the ether and weighing the fat.</p> + +<p>As is shown in the table the sp. gr. is very low, though the +solids and solids not fat are great. The ash, casein, and sugar are +in about the usual proportion. The weight of casein, it is true, is +but half that of the sugar. The milk indeed shows an unusually +great preponderance of the non-nitrogenized elements, and this +seems to correspond with the wants of the animal, since fatty +tissues are greatly developed in elephants. According to Mr. Cross, +who has had large experience with these animals, they are fatter in +the wild state than in bondage. These specimens must appear as +exceptional; they may be considered by some as "strippings;" but as +against such a view we have the recurrence in each sample of the +same characteristics in the milk and a near correspondence in the +composition. As may be seen from the subjoined analyses, given by +v. Gorup Besanez,[1] the milk belongs to the class of which woman's +and mare's milk are members, especially as regards the proportion +of the non-nitrogenized to the nitrogenized elements.</p> + +<p>[Footnote 1: "Lehrhuch der Physiologischen Chemie," pp. 423 and +424.]</p> + +<pre> +Constituents. Woman. Cow. Goat. Ewe. Ass. Mare. +<br> +Water. 86.271 84.28 86.85 83.30 89.01 90.45 +Solids. 13.729 15.72 13.52 16.60 10.99 9.55 +Fat. 5.370 5.47 4.34 6.05 1.85 1.31 +Casein. \ 3.57 2.53 \ \ \ + 2.950 5.73 3.57 2.53 +Albumen. / 0.78 1.26 / / / +Milk Sugar. 5.136 4.34 3.78 3.96 \ 5.42 + 5.05 +Ash. 0.223 0.63 0.65 0.68 / 0.29 +<br> +Constituents. Buffalo. Camel. Sow. Hippo- Elephant. + potamus. +<br> +Water. 80.640 86.34 81.80 90.43 66.697 +Solids. 19.360 13.66 18.20 9.57 33.308 +Fat. 8.450 2.90 6.00 4.51 22.070 +Casein. \ \ \ 4.40 \ + 4.247 3.67 5.30 3.212 +Albumen. / / / / +Milk Sugar. 4.518 5.78 6.07 [1] 7.392 +Ash. 0.845 0.66 0.83 0.11 0.629 +</pre> + +<p>[Footnote 1: Milk Sugar included.]</p> + +<p>It may be remarked that though approaching the composition of +cream it still differs enough to require it to be considered +milk.</p> + +<p>Perhaps if a larger quantity of the milk could be collected, it +would have a more watery character, and approximate more nearly to +other milks in that respect. However this may be the quality of the +fat deserves some attention.</p> + +<p>The fat has a light yellow color, resembling olive oil, is very +pleasant in odor and taste, is liquid at common temperatures, but +solidifies at 18° C. or 64° F.</p> + +<p>The cow must yield a considerable quantity of milk, since the +growth of the calf has been constant, and at the time these samples +were milked the mother gave as freely to her babe as she ever had +since its birth. The calf having gained seven to eight hundred +pounds on a milk diet in one year, it is presumable that it had no +lack of nourishment.</p> + +<p>In size the "Baby" compared equally with other elephants in the +same menagerie, who were known to be four and five years old.</p> + +<p>From whatever standpoint, therefore, we view the lacteal product +of these four-footed giants, we are fully warranted in ascribing to +it not only extreme richness, but also great delicacy of +flavor.</p> + +<hr> +<p><a name="14"></a></p> + +<h2>THE CHEMICAL COMPOSITION OF RICE, MAIZE, AND BARLEY.</h2> + +<h3>By J. STEINER, F.C.S.</h3> + +<p>Rice contains much more starch, but on the other hand, much less +albuminous matter and ash, than maize and barley. The compositions +of different kinds of dried rice do not vary very much, but as the +amount of moisture in the raw grain ranges from 5 to 15 per cent., +no brewer ought to buy rice without having first of all inquired +with the assistance of a chemist as to the percentage of water +present in the sample.</p> + +<p>Another point requiring attention is that of taking notice of +the acidity, which also varies a good deal for different sorts of +rice. In comparing the nutritive values of the three kinds of grain +before us, Pillitz obtained the following numbers:</p> + +<pre> + Barley. Maize. Rice. + -------------- ------------- ------------------ + Air Dried at Air Dried at Air Dried at With + Dry. 100° C. Dry. 100° C. Dry. 100° C. Husk. +<br> +Moisture. 13.88 --- 13.89 --- 12.51 --- 12.00 +Starch. 54.07 62.65 62.69 73.27 74.88 85.41 74.50 +Dextrin and + sugar. 5.66 6.67 3.57 4.14 1.12 1.26 --- +Total albumen + matter. 14.00 16.28 10.63 12.35 9.19 10.40 7.80 +Mineral matter. 2.33 2.70 1.48 1.71 0.84 0.94 2.30 +Fatty matter. 2.30 2.68 4.36 5.03 0.78 0.88 0.30 +Cellulose + matter. 7.76 9.02 3.38 4.50 0.68 1.11 3.10 + ----------------------------------------------------------- + 100.00 100.00 100.00 100.00 100.00 100.00 100.00 +</pre> + +<p>On looking over this table, we notice that rice contains by +about 20 per cent, more starch than barley, and by about 10 to 12 +per cent, more than maize.</p> + +<p>But on the other hand, barley and maize are richer in albuminous +matter and in ash. The extractive matter, <i>i. e.</i>, the part +which is soluble in cold water, is also much greater in barley and +maize than in rice. The extractive matter is for barley 8.7 per +cent., for maize 6.3 per cent., while rice contains only 2.1 per +cent., and it consists in each case of dextrin, sugar, the soluble +part of the ash, and of some nitrogenous matter (soluble +albumen).</p> + +<p>The amount of woody fiber or cellulose is considerable for rice +with its husk, but only slight for samples without husk. The seat +of the mineral matter of the grain of rice is mainly in the husk, +and as this ash is very valuable as nourishment for the yeast +plant, it is an open question whether it would not be preferable to +use for brewing purposes rice with its husk. The comparatively +largest amount of fat is contained in maize; and as such oil is not +desirable for brewing purposes, different recommendations have been +advanced for freeing the grain from it. In the following table some +of the mineral constituents of the three kinds of grain are +compared with each other. These data refer to 100 parts of ash, and +are taken from analysis given by Dr. Emil Wolf.</p> + +<pre> + 100 parts of + Potash Lime Magnesia Phosphoric Silica grain contain + acid ash. +<br> +Barley. 21.9 2.5 8.3 32.8 27.2 2.55 p. ct. +Rice with + husk. 18.4 5.1 8.6 47.2 0.6 7.84 " +Rice without + husk. 23.3 2.9 13.4 51.0 3.0 0.39 " +Maize. 27.0 2.7 14.6 44.7 2.2 1.42 " +</pre> + +<p>The excessive amount of ash in rice with its husk is very +remarkable, and as this mineral matter consists to a great extent +of phosphoric acid and potash, the larger part of it is soluble in +water. Consequently on using rice with its husk for brewing +purposes, the yeast will be provided with a considerable amount of +nutritive substance.</p> + +<p>In conclusion it need hardly be mentioned that the use of rice +with its husk would also be of considerable pecuniary advantage. +There is very little oil in the husk of rice, as shown above by +analysis, and it is not likely that the flavor of the brew would +suffer by it.--<i>London Brewers' Journal.</i></p> + +<hr> +<p><a name="15"></a></p> + +<h2>PETROLEUM OILS.</h2> + +<p>Nothing is in more general use than petroleum, and but few +things are known less about by the majority of persons. It is +hydra-headed. It appears in many forms and under many names. +"Burning fluid" is a popular name with many unscrupulous dealers in +the cheap and nasty. "Burning fluid" is usually another name for +naphtha, or something worse. Gasoline, naphtha, benzine, kerosene, +paraffine, and many other dangerous fluids which make the fireman's +vocation necessary are all the product of petroleum. These oils are +produced by the distillation or refining of crude petroleum, and +inasmuch as the public, especially firemen, are daily brought into +contact with them it is proper that they should know something of +their properties. Refining as commonly practiced involves three +successive operations. The apparatus employed consists of an iron +still connected with a coil or worm of wrought-iron pipe, which is +submerged in a tank of water for the purpose of cooling it. The end +of this pipe is fixed with a movable spout, which can be +transferred or switched from one to another of half a dozen pipes +which come around close to it, but which lead into different tanks +containing different grades of the distillate. When the still has +been filled with crude oil the fire is lighted beneath it, and soon +the oil begins to boil. The first products of distillation are +gases which, at ordinary temperatures, pass through the coil +without being condensed, and escape. When the vapors begin to +condense in the worm the oil trickles from the end of the coil into +the pipe leading to the appropriate receiving tank.</p> + +<p>The first oil obtained is known as gasoline, used in portable +gas machines for making illuminating gas. Then, in turn, come +naphthas of a greater or less gravity, benzine, high test water +white burning oil, such as Pratt's Astral common burning oil or +kerosene, and paraffine oils. When the oil has been distilled it is +by no means fit for use, having a dirty color and most offensive +smell; it is then refined. For this purpose it is pumped into a +large vat or agitator, which holds from two hundred and fifty to +one thousand barrels. There is then added to the oil about two per +cent, of its volume of the strongest sulphuric acid. The whole +mixture is then agitated by means of air pumps, which bring as much +as possible every particle of oil in contact with the acid. The +acid has no affinity for the oil, but it has for the tarry +substance in it which discolors it, and, after the agitation, the +acid with the tar settles to the bottom of the agitator, and the +mixture is drawn off into a lead-lined tank. After the removal of +the acid and tar, the clear oil is agitated with either caustic +soda or ammonia and water. The alkali neutralizes the acid +remaining in the oil, and the water removes the alkali, when the +process of refining is finished. A few refiners improve the quality +of their refined oil by redistilling it after treating it with acid +and alkali. All distillates of petroleum have to be treated with +acid and alkali to refine them. There is one thing peculiar about +the distillates of petroleum, and that is that the run which +follows naphtha, which is called "the middle run oil," is the +highest test oil that is made, running as high as 150 and 160 +degrees flash, while the common oil which follows, viz., from 45 +down to 33 degrees Baume, will range at only about 100 flash, or +115 and 120 degrees burning lest.</p> + +<p>An oil that will stand 100 flash will stand 110 burning test +every time. Kerosene oil, at ordinary temperature, should +extinguish a match as readily as water. When heated it should not +evolve an inflammable vapor below 110 degrees, or, better, 120 +degrees Fahrenheit, and should not take fire below 125 to 140 +degrees Fahrenheit. As the temperature in a burning lamp rarely +exceeds 100 degrees Fahrenheit, such an oil would be safe. It would +produce no vapors to mix with the air in the lamp and make an +explosive mixture; and, if the lamp should be overturned, or +broken, the oil would not be liable to take fire. The crude naphtha +sells at from three to five cents per gallon, while the refined +petroleum or kerosene sells at from fifteen to twenty cents. As +great competition exists among the refiners, there is a strong +inducement to turn the heavier portions of the naphtha into the +kerosene tank, so as to get for it the price of kerosene. In this +way the inflammable naphtha or benzine is sometimes mixed with the +kerosene, rendering the whole highly dangerous. Dr. D. B. White, +President of the Board of Health of New Orleans, found that +experimenting on oil which flashed at 113 degrees Fahrenheit, an +addition of one per cent. of naphtha caused it to flash at 103 +degrees; two per cent. brought the flashing point down to 92 +degrees, five per cent. to 83 degrees, ten per cent. to 59 degrees, +and twenty per cent. of naphtha added brought the flashing point +down to 40 degrees Fahrenheit. After the addition of twenty per +cent. of naphtha the oil burned at 50 degrees Fahrenheit. There are +two distinct tests for oil, the flashing test and the burning test. +The flashing test determines the flashing point of the oil, or the +lowest temperature at which it gives off an inflammable vapor. This +is the most important test, as it is the inflammable vapor, evolved +at atmospheric temperatures, that causes most accidents. Moreover, +an oil which has a high flashing test is sure to have a high +burning test, while the reverse is not true. The burning test fixes +the burning point of the oil, or the lowest temperature at which it +takes fire. The burning point of an oil is from ten to fifty +degrees Fahrenheit higher than the flashing point. The two points +are quite independent of each other; the flashing point depends +upon the amount of the most volatile constituents present, such as +naphtha, etc., while the burning point depends upon the general +character of the whole oil. One per cent. of naphtha will lower the +flashing point of an oil ten degrees without materially affecting +the burning test. The burning test does not determine the real +safety of the oil, that is, the absence of naphtha. The flashing +test should, therefore, be the only test, and the higher the +flashing point the safer the oil.</p> + +<p>In regard to the danger of using the lighter petroleum oils, the +following, under the head of "Naphtha and Benzine under False +Names," is taken from Prof. C. F. Chandler's article on "Petroleum" +in Johnson's Cyclopedia. He says: "Processes have been patented, +and venders have sold rights throughout the country, for patented +and secret processes for rendering gasoline, naphtha, and benzine +non-explosive. Thus treated, these explosive oils, just as +explosive as before the treatment, are sold throughout the country +under trade names. These processes are not only totally +ineffective, but they are ridiculous. Roots, gums, barks, and salts +are turned indiscriminately into the benzine, to leave it just as +explosive as before. No wonder we have kerosene accidents, with +agents scattered through the country selling county rights and +teaching retail dealers how to make these murderous 'non-explosive' +oils. The experiments these venders make to deceive their dupes are +very convincing. None of the petroleum products are explosive +<i>per se</i>, nor are their vapors explosive under all +circumstances when mixed with air. A certain ratio of air to vapor +is necessary to make an explosive mixture. Equal volumes of vapor +and air will not explode; three parts of air and one of vapor gives +a vigorous puff when ignited in a vessel; five volumes of air to +one of vapor gives a loud report. The maximum degree of violence +results from the explosion of eight or nine parts of air mixed with +vapor. It requires considerable skill to make at will an explosive +mixture with air and naphtha, and it is consequently very easy for +the vender not to make one. In most cases the proportion of vapor +is too great, and on bringing a flame in contact with the mixture +it burns quietly. The vender, to make his oil appear non-explosive, +unscrews the wick-tube and applies a match, when the vapor in the +lamp quietly takes fire and burns without explosion. Or he pours +some of the 'safety oil' into a saucer and lights it. There is no +explosion, and ignorant persons, biased by the saving of a few +cents per gallon, purchase the most dangerous oils in the market. +It is not possible to make gasoline, naphtha, or benzine safe by +any addition that can be made to it. Nor is any oil safe that can +be set on fire at the ordinary temperature of the air. Nothing but +the most stringent laws, making it a State prison offense to mix +naphtha and illuminating oil, or to sell any product of petroleum +as an illuminating oil or fluid to be used in lamps, or to be +burned, except in air gas machines, that will evolve an inflammable +vapor below 100 degrees, or better, 120 degrees Fahrenheit, will be +effectual in remedying the evil. In case of an accident from the +sale of oil below the standard, the seller should be compelled to +pay all damages to property, and, if a life is sacrificed, should +be punished for manslaughter. It should be made extremely hazardous +to sell such oils." Prof Chandler is professor of analytical +chemistry, School of Mines, Columbia College.</p> + +<p>There is no substance on earth, or under the earth, which will +chemically combine with naphtha, or that will destroy its peculiar +volatile and explosive properties. The manufacturers of petroleum +products have exhausted the whole resources of chemistry to make +this product available as a safe burning oil, and their inability +to do so proclaims the fact that it cannot be done. Chemistry has +shown that naphtha, and, in fact, the other products of petroleum, +will not part with their hydrogen or change the nature of their +compounds, except by decomposition from a union with oxygen, that +is, by combustion. These humbugs, who deceive people for their own +gains, may put camphor, salt, alum, potatoes, etc., into naphtha, +and call it by whatever fancy name they please. The camphor is +dissolved, the salt partially; potatoes have no effect whatever. +The camphor may disguise the smell of the naphtha, and sometimes +myrhane or burnt almonds may be used for the same purpose. But, no +matter what is used, the liability to explosion is not lessened in +any degree. The stuff is always dangerous and always will be. There +is not much danger in the use of kerosene, if it is of the standard +required by law in several of the States. At the same time +petroleum is dangerous under certain conditions. Where oil is +heated it is more or less inflammable, and, in fact, inflammability +is only a question of temperature of the oil, after all. Burning +oils should be kept in a moderately cool place, and always with +care. Of course, if a lighted lamp is dropped and broken, the oil +is liable to take fire, though the lamp may be put out in the fall, +or the light drowned by the oil, or the oil not take fire at all. +This will be the effect if the oil is cool and of high flash test. +When a lamp is lighted, and remains burning for some time, it +should never be turned down and set aside. The theory is, that +while lighting, a certain supply of gas is created from the oil, +and that when the wick is turned down that supply still continues +to flow out, and not being consumed, forms an inflammable gas in +the chimney, which will explode when a sufficient quantity of air +is mixed with it in the presence of light, which may happen if a +person blows down the chimney; but a lamp should never be +extinguished in that way. A good, high test kerosene oil can be +made with ordinary care as safe as sperm oil, though, of course, it +is not so safe as a matter of fact. We are sure to hear of it when +an accident happens, but we never hear of the reckless use of +kerosene where an accident does not occur, and yet there are few +things so generally carelessly handled as burning +oils.--<i>Fireman's Journal</i></p> + +<hr> +<p><a name="16"></a></p> + +<h2>COMPOSITION OF THE PETROLEUM OF THE CAUCASUS.</h2> + +<h3>By MM. P SCHUTZENBERGER and N. TONINE.</h3> + +<p>All portions of this petroleum contain saturated carbides of the +formula C<sub>nH</sub><sub>2n</sub>, which the authors name +paraffenes. At a bright red heat they yield benzinic carbides, +C<sub>nH</sub><sub>2n-6</sub>, naphthalin and a little anthracen. +At dull redness the products are along with unaltered paraffenes, +products which unite energetically with bromine, and which are +converted into resinous polymers of ordinary sulphuric acid. It is +difficult to isolate, by means of fractional distillation, definite +products with constant boiling points.</p> + +<hr> +<p><a name="17"></a></p> + +<h2>NOTES ON CANANGA OIL OR ILANG-ILANG OIL.</h2> + +<p>[Footnote: From the <i>Archiv der Pharmacie</i>.]</p> + +<h3>By F. A. FLÜCKIGER.</h3> + +<p>This oil, on account of its fragrance, which is described by +most observers as extremely pleasant, has attained to some +importance, so that it appears to me not superfluous to submit the +following remarks upon it and the plant from which it is +derived.</p> + +<p>The tree, of which the flowers yield the oil known under the +name "Ilang-ilang" or "Alanguilan," is the <i>Cananga odorata</i>, +Hook. fil. et Thomp.,[1] of the order Unonaceæ, for which +reason it is called also in many price lists "Oleum Anonæ," +or "Oleum Unonæ" It is not known to me whether the tree can +be identified in the old Indian and Chinese literature.[2] In the +west it was first named by Ray as "Arbor Saguisan," the name by +which it was called at that time at Luçon[3] Rump[4] gave a +detailed description of the "Bonga Cananga," as the Malays +designate the tree ("Tsjampa" among the Javanese); Rumph's figure, +however is defective. Further, Lamarck[5] has short notices of it +under "Canang odorant, <i>Uvaria odorata</i>." According to +Roxburgh,[6] the plant was in 1797 brought from Sumatra to the +Botanical Gardens in Calcutta. Dunal devoted to the <i>Ucaria +odorata</i>, or, properly, <i>Unona odorata</i>, as he himself +corrected it, a somewhat more thorough description in his +"Monographic de la Famille des Anonacees,"[7] which principally +repeats Rumph's statements.</p> + +<p>[Footnote 1: "Flora Indica," i (1855), 130.]</p> + +<p>[Footnote 2: "No mention of any plant or flowers, which might be +identified with Cananga, can be traced in any Sanskrit works."--Dr. +Charles Rice, <i>New Remedies</i>, April, 1881, page 98.]</p> + +<p>[Footnote 3: Ray. "Historia Plantarum, Supplementum," tomi i et +ii "Hist. Stirpium Insulæ Luzonensis et Philippinarum" a +Georgio Josepho Canello; London, 1704, 83]</p> + +<p>[Footnote 4: "Herbarium Amboinense, Amboinsch Kruidboek," ii. +(Amsterdam, 1750), cap. xix, fol. 195 and tab. 65.]</p> + +<p>[Footnote 5: "Encyclopédie méthodique. Botanique," +i (1783), 595.]</p> + +<p>[Footnote 6: "Flora Indica," ii. (Serampore, 1832), 661.]</p> + +<p>[Footnote 7: Paris, 1817, p. 108, 105.]</p> + +<p>Lastly, we owe a very handsome figure of the <i>Cananga +odorata</i> to the magnificent "Flora Javæ," of Blume;[1] a +copy of this, which in the original is beautifully colored, is +appended to the present notice. That this figure is correct I +venture to assume after having seen numerous specimens in Geneva, +with De Candolle, as well as in the Delessert herbarium. The +unjustifiable name <i>Unona odoratissima</i>, which incorrectly +enough has passed into many writings, originated with Blanco,[2] +who in his description of the powerful fragrance of the flowers, +which in a closed sleeping room produces headache, was induced to +use the superlative "odoratissima." Baillon[3] designated as +Canangium the section of the genus <i>Uvaria</i>, from which he +would not separate the Ilang-ilang tree.</p> + +<p>[Footnote 1: Vol. i. (Brussels, 1829), fol. 29, tab ix et xiv. +B.]</p> + +<p>[Footnote 2: "Flora de Filipinas," Manila, 1845, 325. <i>Unona +odoratissima</i>, Alang-ilan. The latter name, according to +Sonnerat, is stated by the Lamarck to be of Chinese origin; Herr +Reymann derives it from the Tagal language.]</p> + +<p>[Footnote 3: "Dictionnaire de Botanique."]</p> + +<p class="ctr"><a href="images/7a.png"><img src= +"images/7a_th.png" alt="CANAGA ODORATA"></a></p> + +<p class="ctr">CANAGA ODORATA</p> + +<p>The notice of Maximowicz,[1] "Ueber den Ursprung des Parfums +Ylang-Ylang," contains only a confirmation of the derivation of the +perfume from Cananga.</p> + +<p>[Footnote 1: Just's "Botanischer Jahresbericht," 1875, 973.]</p> + +<p><i>Cananga odorata</i> is a tree attaining to a height of 60 +feet, with few but abundantly ramified branches. The shortly +petioled long acuminate leaves, arranged in two rows, attain a +length of 18 centimeters and a breadth of 7 centimeters; the leaf +is rather coriaceous, and slightly downy only along the nerves on +the under side. The handsome and imposing looking flowers of the +<i>Cananga odorata</i> occur to the number of four on short +peduncles. The lobes of the tripartite leathery calyx are finally +bent back. The six lanceolate petals spread out very nearly flat, +and grow to a length of 7 centimeters and a breadth of about 12 +millimeters; they are longitudinally veined, of a greenish color, +and dark brown when dried. The somewhat bell-shaped elegantly +drooping flowers impart quite a handsome appearance, although the +floral beauty of other closely allied plants is far more striking. +The filaments of the Cananga are very numerous; the somewhat +elevated receptacle has a shallow depression at the summit. The +green berry-like fruit is formed of from fifteen to twenty +tolerably long stalked separate carpels which inclose three to +eight seeds arranged in two rows. The umbel-like peduncles are +situated in the axils of the leaves or spring from the nodes of +leafless branches. The flesh of the fruit is sweetish and aromatic. +The flowers possess a most exquisite perfume, frequently compared +with hyacinth, narcissus, and cloves.</p> + +<p><i>Cananga odorata</i>, according to Hooker and Thomson or +Bentham and Hooker,[1] is the only species of this genus; the +plants formerly classed together with it under the names +<i>Unona</i> or <i>Uvaria</i>, among which some equally possess +odorous flowers, are now distributed between those two genera, +which are tolerably rich in species. From <i>Uvaria</i> the +<i>Cananga</i> differs in its valvate petals, and from <i>Unona</i> +in the arrangement of the seeds in two rows.</p> + +<p>[Footnote 1: "Genera Plantarum," i, (1864), 24.]</p> + +<p><i>Cananga odorata</i> is distributed throughout all Southern +Asia, mostly, however, as a cultivated plant. In the primitive +forest the tree is much higher, but the flowers are, according to +Blume, almost odorless. In habit the Cananga resembles the +<i>Michelia champaca</i>, L.,[1] of the family Magnoliaceæ, +an Indian tree extraordinarily prized on account of the very +pleasant perfume of its yellow flowers, and which was already +highly celebrated in ancient times in India. Among the admired +fragrant flowers which are the most prized by the in this respect +pampered Javanese, the "Tjempaka" (<i>Michelia champaca</i>) and +the "Kenangga wangi" (<i>Cananga odorata</i>)[2] stand in the first +rank.</p> + +<p>[Footnote 1: A beautiful figure of this also is given in Blume's +"Flora Javæ," iii., Magnoliaceæ, tab. I.]</p> + +<p>[Footnote 2: Junghuhn, Java, Leipsic, 1852, 166.]</p> + +<p>It is not known to me whether the oil of cananga was prepared in +former times. It appears to have first reached Europe about 1864; +in Paris and London its choice perfume found full recognition.[1] +The quantities, evidently only very small, that were first imported +from the Indian Archipelago were followed immediately by somewhat +larger consignments from Manila, where German pharmacists occupied +themselves with the distillation of the oil.[2]</p> + +<p>[Footnote 1: <i>Jahresbericht d. Pharmacie</i>, by Wiggers and +Husemann, 1867, 422.]</p> + +<p>[Footnote 2: <i>Jahresbericht</i>, 1868, 166.]</p> + +<p>Oscar Reymann and Adolf Ronsch, of Manila, exhibited the +ilang-ilang oil in Paris in 1878; the former also showed the +Cananga flowers. The oil of the flowers of the before-mentioned +<i>Michelia champaca</i>, which stood next to it, competes with the +cananga oil, or ilang-ilang oil, in respect to fragrance.[1] How +far the latter has found acceptance is difficult to determine; a +lowering of the price which it has undergone indicates probably a +somewhat larger demand. At present it may be obtained in Germany +for about 600 marks (£30) the kilogramme.[2] Since the +Cananga tree can be so very easily cultivated in all warm +countries, and probably everywhere bears flowers endowed with the +same pleasant perfume, it must be possible for the oil to be +produced far more cheaply, notwithstanding that the yield is always +small.[3] It may be questioned whether the tree might not, for +instance, succeed in Algeria, where already so many exotic +perfumery plants are found.</p> + +<p>[Footnote 1: <i>Archiv der Pharmacie</i>, ccxiv. (1879), +18.]</p> + +<p>[Footnote 2: According to information kindly supplied by Herr +Reymann, in Paris, Nice, and Grasse, annually about 200 kilogrammes +are used; in London about 50 kilogrammes, and equally as much in +Germany (Leipsic, Berlin, Frankfort).]</p> + +<p>[Footnote 3: 25 grammes of oil from 5 kilogrammes of flowers, +according to Reymann.]</p> + +<p>According to Guibourt,[1] the "macassar oil," much prized in +Europe for at least some decades as a hair oil, is a cocoa nut oil +digested with the flowers of <i>Cananga odorata</i> and <i>Michelia +champaca</i>, and colored yellow by means of turmeric. In India +unguents of this kind have always been in use.</p> + +<p>[Footnote 1: <i>Histoire Naturelle des Drogues Simples</i>, iii. +(1850), 675.]</p> + +<p>The name "Cananga" is met with in Germany as occurring in former +times. An "Oleum destillatum Canangæ" is mentioned by the +Leipsic apothecary, Joh. Heinr. Linck[1] among "some new exotics" +in the "Sammlung von Naturund Medicin- wie, auch hierzu gehorigen +Kunst- und Literatur Geschichten, so sich Anno 1719 in Schlesien +und andern Ländern begeben" (Leipsic und Budissin, 1719). As, +however, the fruit of the same tree sent together with this cananga +oil is described by Linck as uncommonly bitter, he cannot probably +here refer to the present <i>Cananga odorata</i>, the fruit-pulp of +which is expressly described by Humph and by Blume as sweetish. +Further an "Oleum Canangæ, Camel-straw oil," occurs in 1765 +in the tax of Bremen and Verden.[2] It may remain undetermined +whether this oil actually came from "camel-straw," the beautiful +grass <i>Andropogon laniger</i>.</p> + +<p>[Footnote 1: Compare Flückiger, "Pharmakognosic," 2d edit, +1881, p. 152.]</p> + +<p>[Footnote 2: Flückiger, "Documente zur Geschichte der +Pharmacie," Halle (1876), p 93.]</p> + +<p>From a chemical point of view cananga oil has become interesting +because of the information given by Gal,[1] that it contains +benzoic acid, no doubt in the form of a compound ether. So far as +I, at the moment, remember the literature of the essential oils, +this occurrence of benzoic acid in plants stands alone,[2] although +in itself it is not surprising, and probably the same compound will +yet be frequently detected in the vegetable kingdom. As it was +convenient to test the above statement by an examination I induced +Herr Adolf Convert, a pharmaceutical student from +Frankfort-On-Main, to undertake an investigation of ilang-ilang oil +in that direction. The oil did not change litmus paper moistened +with alcohol. A small portion distilled at 170° C.; but the +thermometer rose gradually to 290°, and at a still higher +temperature decomposition commenced. That the portions passing over +below 290° had a strong acid reaction already indicated the +presence of ethers. Herr Convert boiled 10 grammes of the oil with +20 grammes of alcohol and 1 gramme of potash during one day in a +retort provided with a return condenser. Finally the alcohol was +separated by distillation, the residue supersaturated with dilute +sulphuric acid, and together with much water submitted to +distillation until the distillate had scarcely an acid reaction. +The liquid that had passed over was neutralized with barium +carbonate, and the filtrate concentrated, when it yielded crystals, +which were recognized as nearly pure acetate. The acid residue, +which contained the potassium sulphate, was shaken with ether; +after the evaporation of the ether there remained a crystalline +mass having an acid reaction which was colored violet with ferric +chloride. This reaction, which probably may be ascribed to the +account of a phenol, was absent after the recrystallization of the +crystalline mass from boiling water. The aqueous solution of the +purified crystalline scales then gave with ferric chloride only a +small flesh-colored precipitate. The crystals melted at 120° C. +In order to demonstrate the presence of benzoic acid Herr Convert +boiled the crystals with water and silver oxide and dried the +scales that separated from the cooling filtrate over sulphuric +acid. 0.0312 gramme gave upon combustion 0.0147 gramme of silver, +or 47.1 per cent. The benzoate of silver contains 46.6 per cent, of +metal; the crystals prepared from the acid of ilang-ilang oil were, +therefore, benzoate of silver. For the separation of the alcoholic +constituent, which is present in the form of an apparently not very +considerable quantity of benzoic ether, far more ilang-ilang oil +would be required than was at command.</p> + +<p>[Footnote 1: <i>Comptes Rendus</i>, lxxvi. (1873), 1428, and +abstracted in the <i>Pharmaceutical Journal</i> [3], iv., p. 28; +also in <i>Jahresbericht</i>, 1873, p. 431.]</p> + +<p>[Footnote 2: Overlooking Peru balsam and Tolu balsam.]</p> + +<p>Besides the benzoic ether and, probably, a phenol, mentioned +above, there may be recognized in ilang-ilang oil an aldehyde or +ketone, inasmuch as upon shaking it with bisulphite of sodium I +observed the formation of a very small quantity of crystals. That +Gal did not obtain the like result must at present remain +unexplained. Like the benzoic acid the acetic acid is, no doubt, +present in cananga oil in the form of ether.</p> + +<hr> +<p><a name="18"></a></p> + +<h2>CHIAN TURPENTINE.</h2> + +<p>The following letter has been received by the editors of the +<i>Repertoire de Pharmacie:</i> For some months past, a good deal +has been heard about a product of our island that had quite fallen +into disuse, and which no one cared to gather, so much had the +demand fallen off because a substitute for it had been found in +Europe; I mean Chian turpentine.</p> + +<p>As this product is destined to take a certain part in the +treatment of cancer, according to some English physicians, permit +me, sir, to give your readers a few interesting details, obtained +on the spot, concerning the turpentine tree and its product.</p> + +<p>The turpentine tree (<i>Pistacia terebinthus</i> L.) has existed +in our island for many centuries, judging from the enormous +dimensions of some of these trees, compared, too, with their slow +rate of growth. The trunks of some measure from 4 to 5 meters in +circumference, and their heights vary from 15 to 20 meters. On my +own land there is an enormous tree, by far the largest on the +island, the circumference of its trunk being 6 meters. Many of +these great trees have been used in the construction of mills, +presses, etc., on account of the hardness of their wood. It is in +the vicinity of the town and in three or four neighboring villages +that these trees are found. To-day, at a careful estimate, there +may be 1,500 trees capable of yielding 2,000 kilos of turpentine, +mixed with at least 30 per cent of foreign matter. There are no +appliances for refining the product here, except the sieves through +which it is passed to remove the pebbles and bits of wood which are +found in it.</p> + +<p>It is gathered from incisions made in the tree in June. Axes are +used for this purpose, and the incision must be through the whole +thickness of the bark. Through these outlets the turpentine falls +to the foot of the tree, and mixes with the earth there. On its +first appearance the turpentine is of a sirupy consistence, and is +quite transparent; gradually it becomes more opaque, and of a +yellowish-white color. It is at this period also that it gives off +its characteristic odor most abundantly.</p> + +<p>It is, however, not the product "turpentine" that is most +esteemed by the natives, but the fruit of the tree, a kind of drupe +disposed in clusters. The fruit is improved by the incisions made +in the tree for the escape of the turpentine, otherwise the resin, +having no other outlet, would impregnate the former, hinder its +complete development, and render it useless for the purposes for +which it is cultivated. One circumstance worth noting is that, as +soon as the fruit commences to ripen, the flow of turpentine +completely ceases. This is toward August; the fruit is then green; +it is gathered, dried in the sun, bruised, and a fine +yellowish-green oil is drawn from it, which is soluble in ether. +This oil is used for alimentary purposes, but rarely for +illumination since the introduction of petroleum. It is mostly used +in making sweet cakes, and often as a substitute for butter, in all +cases where the latter is employed. I use it daily myself without +perceiving any difference.</p> + +<p>I may here be permitted to correct a slight mistake that has +crept into several standard botanical works. It is therein stated +that the inhabitants of this country extract from the fruit of the +lentisc (<i>Pistacia lentiscus</i> L., a well-known shrub growing +on this island, from which Chian mastic is obtained), an alimentary +and illuminating oil. This fruit has never been gathered for its +oil within the memory of man. The lentisc has probably been thus +mistaken for the turpentine tree.</p> + +<p>For the last twenty years the gathering of turpentine has been +almost abandoned, although the incisions in the trees have been +regularly made, but the value was so small that proprietors did not +care to collect it, and left it to run to waste. There were but a +few pharmacists of Smyrna and the neighboring islands who took a +small quantity for making medicinal plasters. An utterly +insignificant quantity found its way into Europe. How is it then +that, after so many years, it was found in Europe? The problem is +easily explained--the greater part came from Venice. This is +indubitable, and, lately, an English chemist, Mr. W. Martindale, in +a communication to the Chemical Society of London, expressed doubts +as to the authenticity of the turpentine used in the treatment of +cancer. If turpentine can really somewhat relieve this disease, and +if this treatment is generally accepted in Europe, I much fear you +will only obtain substitutions of very inferior quality to the +turpentine produced in our island.</p> + +<p>This year the Chians have been surprised by an extensive demand +for this product, from London in the first place, and secondly from +Vienna, and the proprietors, although but poorly provided at the +moment, sent away nearly 600 kilos Paris has not yet made any +demand. Yours, etc.,</p> + +<p>DR. STIEPOWICH.</p> + +<p>Chio, Turkey.</p> + +<hr> +<p><a name="19"></a></p> + +<h2>ON THE CHANGE OF VOLUME WHICH ACCOMPANIES THE GALVANIC +DEPOSITION OF A METAL.</h2> + +<h3>By M. E. BOUTY.</h3> + +<p>In previous notes I have established, first, that the galvanic +depositions experience a change of volume, from which there results +a pressure exercised on the mould which receives them; second, that +the Peltier phenomenon is produced at the surface of contact of an +electrode and of an electrolyte. Fresh observations have caused me +to believe that the two phenomena are connected, and that the first +is a consequence of the second. The Peltier effect can clearly be +proved when the electrolysis is not interfered with by energetic +secondary actions, and particularly with the sulphate and nitrate +of copper, the sulphate and chloride of zinc, and the sulphate and +chloride of cadmium. For any one of these salts it is possible to +determine a value, I, of the intensity of the current which +produces the metallic deposit such that, for all the higher +intensities the electrode becomes heated, and such that it becomes +cold for less intensities. I will designate this intensity, I, +under the name of <i>neutral point of temperatures</i>.</p> + +<p>The new fact which I have observed is, that in the electrolysis +of the same salts it is always possible to lower the intensity of +the current below a limit, I', such that the compression produced +by the deposit changes its direction, that is to say, instead of +contracting the metal dilates in solidifying. This change, although +unquestionable, is sufficiently difficult to produce with sulphate +of copper. It is necessary to employ as a negative electrode a +thermometer sensitive to 1/200 of a degree, and to take most +careful precautions to avoid accidental deformations of the +deposit; but the phenomenon can be observed very easily with +nitrate of copper, the sulphate of zinc, and the chloride of +cadmium. There is, therefore, a <i>neutral point of compression</i> +in the same cases where there is a neutral point of temperatures. +With the salts of iron, nickel, etc., for which the neutral point +of temperatures cannot be arrived at, there is also no neutral +point of compression; and the negative electrode always becomes +heated, and the deposit obtained is always a compressing +deposit.</p> + +<p>I have determined, by the help of observations made with ten +different current strengths, the constants of the formulæ +which I have explained elsewhere, and which gives the apparent +excess, y, of the thermometer electrode compressed by the metallic +deposit in terms of the time, t, during which the metal was +depositing:</p> + +<pre> + A t + (1) y = ------- + B + t +</pre> + +<p>The constant, A, is proportional to the variation of volume of +the unit of volume of the metal. The values of A, without being +exactly regular, are sufficiently well represented within practical +limits by the formula:</p> + +<pre> + (2) A = - a'i + b'i², +</pre> + +<p>of the same form as the expression E:</p> + +<pre> + E = - ai + bi², +</pre> + +<p>of the heating of the thermometer electrode. Further, every +cause which affects the coefficients, a or b, also affects in the +same way a' and b': such causes being the greater or less dilution +of the solution, the nature of the salt, etc. It is, therefore, +impossible not to be struck by the direct relation of the thermic +and mechanical phenomena of which the negative electrode is the +origin. The following is the explanation which I offer: The +thermometer indicates the mean temperature of the liquid just +outside it; this temperature is not necessarily that of the metal +which incloses it. The current, propagated almost exclusively by +the molecules of the decomposed salt, does not act directly to +cause a variation in the temperature of the dissolving molecules; +these change heat with the molecules of the electrolyte, which +should be in general hotter than those when a heating is noticed +and colder when a cooling is observed. Suppose it is found, in the +first case, that the metal, at the moment when it is deposited, is +hotter than the liquid, and, consequently, than the thermometer; it +becomes colder immediately after the deposit, and consequently +contracts; the deposit is compressed. The reverse is the case when +the metal is colder than the liquid; the deposit then dilates. If +this hypothesis is correct, the excess, T, of the temperature of +the metal over the liquid which surrounds the thermometer should be +proportional to the contraction, A, represented by the formula (2), +and the neutral point, I', of the contraction corresponds to the +case where the temperature of the metal is precisely equal to that +of the liquid.</p> + +<p>It might be expected, perhaps, from the foregoing, that I' = I; +this would take place if the excess of temperature of the metal, +measured by the contraction, were rigorously proportional to the +heating of the liquid, for then the two quantities would be null at +the same time. Careful experiment proves that this is not the case. +The sulphate of copper gives compressing deposits on a thermometer +which is undoubtedly cooling; chloride of zinc of a density 200 can +give expanding deposits on a thermometer which is heating. There +is, therefore, no proportionality; but it must be remarked that the +temperature of the metal which is deposited does not depend only on +the quantities of heat disengaged in an interval of molecular +thickness which is infinitely small compared with the thickness of +the layer, of which the variations of temperature are registered by +the thermometer. There is nothing surprising, therefore, that the +two variations of temperature, according exactly with one another, +do not follow identically the same laws.--<i>Comptes +Rendus.</i></p> + +<hr> +<p><a name="20"></a></p> + +<h2>ANALYSES OF RICE SOILS FROM BURMAH.</h2> + +<h3>By R. ROMANIS, D.Sc., Chemical Examiner, British Burmah.</h3> + +<p>The analyses of rice soils was undertaken at the instance of the +Revenue Settlement Survey, who wanted to know if the chemical +composition of the soil corresponded in any way to the valuation as +fixed from other evidence. It was found that the amount of +phosphoric acid in the soil in any one district corresponded pretty +well with the Settlement Officers' valuation, but on comparing two +districts it was found that the district which was poorer in +phosphoric acid gave crops equal to the richer one. On inquiry it +was found that in the former the rice is grown in nurseries and +then planted out by hand, whereas in the latter, where the holdings +are much larger, the grain is sown broadcast. The practice of +planting out the young crops enables the cultivator to get a +harvest 20 per cent. better than he would otherwise do, and hence +the poorer land equals the richer.</p> + +<p>The deductions drawn from this investigation are, first, that, +climate and situation being equal, the value of soil depends on the +phosphoric acid in it; and, second, that the planting-out system is +far superior to the broadcast system of cultivation for rice.</p> + +<p>Results of two analyses of soils from Syriam, near Rangoon, are +appended:</p> + +<pre> + _Soluble in Hydrochloric Acid_. +<br> + I. II. + Virgin Soil. +Organic matter 4.590 8.5?8 +Oxide of iron and alumina 8.939 7.179 +Magnesia 0.469 0.677 +Lime trace. 0.131 +Potash 0.138 0.187 +Soda 0.136 0.337 +Phosphoric acid 0.100 0.108 +Sulphuric acid 0.025 0.117 +Silica ---- 0.005 + -------- --------- + 14.397 17.249 +<br> + _Soluble in Sulphuric Acid_. +<br> +Alumina 17.460 15.684 +Magnesia 0.459 0.446 +Lime 0.286 trace. +Potash 0.616 1.250 +Soda 0.317 0.285 + --------- --------- + 19.138 17.665 +<br> + _Residue_. +<br> +Silica, soluble 11.675 \ + 69.546 + " insoluble 49.477 / +Alumina 3.062 4.178 +Lime 0.700 0.134 +Magnesia 0.212 trace. +Potash 0.276 1.180 +Soda 0.503 1.048 + -------- --------- + 100.000 100.000 +</pre> + +<p>These are alluvial soils from the Delta of the Irrawaddy.</p> + +<hr> +<p><a name="1"></a></p> + +<h2>DRY AIR REFRIGERATING MACHINE.</h2> + +<p>A large number of scientific and other gentlemen interested in +mechanical refrigeration lately visited the works of Messrs. J. +& E. Hall, of Dartford, to inspect the working of one of their +improved horizontal dry air refrigerators!</p> + +<p>The machine, which is illustrated below, is designed to deliver +about 10,000 cubic feet of cold air per hour, when running at the +rate of 100 revolutions per minute, and is capable of reducing the +temperature of the air from 90 deg. above, to about 50 deg. below +zero, Fah., with an initial temperature of cooling water of 90 deg. +to 95 deg. Fah. It can, however, be run at as high a speed as 140 +revolutions per minute. The air is compressed in a water-jacketed, +double-acting compression cylinder, to about 55 lb. per square inch +--more or less according to the temperature of the cooling +water--the inlet valve being worked from a cam on the crank shaft, +to insure a full cylinder of air at each stroke, and the outlet +valves being self acting, specially constructed to avoid noise in +working and breakages, which have given rise to so much annoyance +in other cold air machines. The compressed air, still at a high +temperature, is then passed through a series of tubular coolers, +where it parts with a great deal of its heat, and is reduced to +within 4 deg. or 5 deg. of the initial temperature of the cooling +water. Here also a considerable portion of the moisture, which, +when fresh air is being used, must of necessity enter the +compression cylinder, is condensed and deposited as water.</p> + +<p class="ctr"><img src="images/9a.png" alt= +"COMPRESSION CYLINDER. SCALE 1/60"></p> + +<p class="ctr">COMPRESSION CYLINDER. SCALE 1/60</p> + +<p>After being cooled, the compressed air is then admitted to the +expansion cylinder, but as it still contains a large quantity of +water in solution, which, if expansion was carried immediately to +atmospheric pressure, would, from the extreme cold, be converted +into snow and ice, with a positive certainty of causing great +trouble in the valves and passages. It is got rid of by a process +invented by Mr. Lightfoot, which is at the same time extremely +simple and beautiful in action, and efficient. Instead of reducing +the compressed air at once to atmospheric pressure, it is at first +only partially expanded to such an extent that the temperature is +lowered to about 35 deg. to 40 deg. Fah., with the result that very +nearly the whole of the contained aqueous vapor is condensed into +water. The partially expanded air which now contains the water as a +thick mist is then admitted into a vessel containing a number of +grids, through which it passes, parting all the while with its +moisture, which gradually collects at the bottom and is blown off. +The surface area of the grids is so arranged that by the time the +air has passed through them it is quite free from moisture, with +the exception of the very trifling amount which it can hold in +solution at about 35 deg. Fah., and 30 lb. pressure. The expansion +is then continued to atmospheric pressure and the cooled air +containing only a trace of snow is then discharged ready for use +into a meat chamber or elsewhere. In small machines the double +expansion is carried out in one cylinder containing a piston with a +trunk, the annulus forming the first expansion and the whole piston +area the second, but in larger machines two cylinders of different +sizes are used, just as in an ordinary compound engine. To +compensate for the varying temperature of the cooling water the +cut-off valve to the first or primary expansion is made adjustable; +and this can either be regulated as occasion requires by hand, or +else automatically. The temperature in the depositors being kept +constant under all variations in cooling water, there is the same +abstraction of moisture in the tropics as in colder climates, and +the cold air finally discharged from the machine is also kept at a +uniform temperature.</p> + +<p class="ctr"><img src="images/9b.png" alt=""></p> + +<p class="ctr">Expansion Cylinder. Scale 1/60.92° F. +temperature of entering<br> +air. Cooling water<br> +entering<br> +in at 86° F.</p> + +<p class="ctr"><img src="images/9c.png" alt=""></p> + +<p class="ctr">Expansion Cylinder. Scale 1/60.<br> +68° F. temperature of entering air. Cooling water entering<br> +in at 65° F. 125 revs. per minute, or 312 ft.<br> +per minute per piston speed.</p> + +<p>The diagrams are reduced from the originals, taken from the +compression cylinder when running at the speed of 125 revolutions +per minute, and also from the expansion cylinder, the first when +the cooling water was entering the coolers at 86 deg. Fah., and the +latter when this temperature was reduced to 65 deg. Fah. In all +cases the compressed air is cooled down to within from 3 deg. to 5 +deg. of the initial temperature of the cooling water, thus showing +the great efficiency of the cooling apparatus. The machine has been +run experimentally at Dartford, under conditions perhaps more +trying than can possibly occur, even in the tropics, the air +entering the compression cylinder being artificially heated up to +85 deg. and being supersaturated at that temperature by a jet of +steam laid on for the purpose. In this case no more snow was formed +than when dealing with aircontaining a very much less proportion of +moisture. The vapor was condensed previous to final expansion and +abstracted as water in the drying apparatus. The machine was +exhibited at work in connection with a cold chamber which was kept +at a temperature of about 10 deg. Fah., besides which several +hundredweight of ice were made in the few days during which the +experiments lasted. This machine is in all respects an improvement +on the machine which we have already illustrated. In that machine +Messrs. Hall were trammeled by being compelled to work to the plans +of others. In the present case the machine has been designed by Mr. +Lightfoot, and appears to leave little to be desired. It is a new +thing that a cold air machine may be run at any speed from 32 to +120 revolutions per minute. In its action it is perfectly steady, +and the cold air chamber is kept entirely clear of snow. The +dimensions of the machine are also eminently favorable to its use +on board ship.-<i>The Engineer</i>.</p> + +<p class="ctr"><a href="images/9d.png"><img src= +"images/9d_th.png" alt="DRY AIR REFRIGERATING MACHINE"> +</a></p> + +<p class="ctr">DRY AIR REFRIGERATING MACHINE</p> + +<hr> +<p><a name="2"></a></p> + +<h2>THOMAS'S IMPROVED STEAM WHEEL.</h2> + +<p>The rotary or steam wheel, the invention of J.E. Thomas, of +Carlinville, Ill., shown in the annexed figure, consists of a wheel +with an iron rim inclosed within a casing or jacket from which +nothing protrudes except the axle which carries the driving pulley, +and the grooved distributing disk. Within this jacket, which need +not necessarily be steam-tight, there is a movable piece, K, which, +pressing against the rim, renders steam-tight the channel in which +the pistons move when driven by the steam. At the extremities of +this channel there are plates which are kept pressed against the +wheel by means of spiral springs, thus rendering the channel +perfectly tight.</p> + +<p>The steam enters the closed space (which forms one-fourth of the +circumference) through the slide-valve, S, presses against the +pistons, d, and causes the wheel to revolve in the direction of the +arrows. The slide-valve is closed by the action of the external +distributing mechanism, the piston passes beyond the steam-outlet, +A, and a new piston then comes in play. Altogether, there are six +of these pistons, each one working in an aperture in the rim, and +kept pressed outwardly by means of a spiral spring. The steam acts +constantly on the same lever arm and meets with no +counter-pressure. The other defects, likewise, of the ordinary +steam engines in use are obviated to such an extent that the +effective power of the steam-wheel is 50 per cent, greater than +that of other and more complicated machines--at least this is the +experience of the inventor.</p> + +<p class="ctr"><a href="images/10a.png"><img src= +"images/10a_th.png" alt="IMPROVED STEAM-WHEEL."></a></p> + +<p class="ctr">IMPROVED STEAM-WHEEL.</p> + +<p>To the inner ends of the pistons there are attached rods which +pass through the rim of the wheel (where they are provided with +stuffing-boxes) and abut against spiral springs. These rods are, in +addition, connected with levers, h, which are pivoted on the spokes +of the wheel, and whose other extremities carry rods, 2. These +latter run through guides on the external face of the rim of the +wheel and engage by means of friction-rollers, in an undulating +groove formed in the inner surface of the jacket. When a piston +arrives in front of the upper extremity of the steam channel, the +friction roller at that moment enters one of the depressions in the +groove, and thus lifts up the piston and allows it to pass freely +beyond the plate which closes the channel.</p> + +<hr> +<p><a name="3"></a></p> + +<h2>THE AMERICAN SOCIETY OF CIVIL ENGINEERS.</h2> + +<h3>ADDRESS OF THE PRESIDENT, JAMES BICHENO FRANCIS, AT THE +THIRTEENTH ANNUAL CONVENTION OF THE SOCIETY AT MONTREAL, JUNE 15, +1881.</h3> + +<p>You have assembled in convention for the first time outside the +limits of the United States, and I congratulate you on the +selection of this beautiful city, in which and its immediate +neighborhood there are so many interesting engineering works, +constructed with the skill and solidity characteristic of the +British school of engineering. Nine of our members are Canadian +engineers, which must be the excuse of the other members for +invading foreign territory.</p> + +<p>The society was organized November 3, 1852, and actively +maintained up to March 2, 1855. Eleven only of the present members +date from this period. October 2, 1867, the society was reorganized +on a wider basis, and from that time to the present it has been +constantly increasing in interest and usefulness.</p> + +<p>The membership of the society is now as follows:</p> + +<pre> + Honorary members........ 11 + Corresponding members... 3 + Members................. 491 + Associates.............. 21 + Juniors................. 57 + Fellows................. 53 + ---- + Total................... 636 +</pre> + +<p>During the last year we have lost six members by death and five +by resignation, and fifty-six new members have been elected and +qualified.</p> + +<p>The most interesting event to the society since the last +convention has been the purchase of a house in the City of New +York, as a permanent home, at a cost of $30,000. This has been +accomplished, so far, without taxing the resources of the society, +the required payments having been met by subscription. The sum of +$11,900 had been subscribed to the building fund up to the 25th +ult., by seventy members and twenty-nine friends of the society who +are not members. The subscription is still open, and it is expected +that large additions will be made to it by members and their +friends to enable the society to make the remaining payments +without embarrassment.</p> + +<p>Meetings of the society are held twice in each month during ten +months in the year, for the reading and discussion of papers and +other purposes. The new house affords much better accommodations +for these purposes than we have ever had before, and also for the +library, which now contains 8,850 books and pamphlets, and is +constantly increasing. A catalogue of the library is being +prepared. Part I., embracing railroads and the transactions of +scientific societies, has been printed and furnished to +members.</p> + +<h3>WATER POWER.</h3> + +<p>Water power in many of the States is abundant and contributes +largely to their prosperity. Its proper development calls for the +services of the civil engineer, and as it is the branch of the +profession with which I am most familiar, I propose to offer a few +remarks on the subject.</p> + +<p>The earliest applications were to grist and saw mills; carding +and fulling mills soon followed; these were essential to the +comfort of the early settlers who relied on home industries for +shelter, food, and clothing, but with the progress of the country +came other requirements.</p> + +<p>The earliest application of water power to general manufacturing +purposes appears to have been at Paterson, New Jersey, where "The +Society for Establishing Useful Manufactures" was formed in the +year 1791. The Passaic River at this point furnishes, when at a +minimum, about eleven hundred horse power continuously night and +day.</p> + +<p>The water power at Lowell, Massachusetts, was begun to be +improved for general manufacturing purposes in 1822. The Merrimack +River at this point has a fall of thirty-five feet, and furnishes, +at a minimum, about ten thousand horse power during the usual +working hours.</p> + +<p>At Cohoes, in the State of New York, the Mohawk River has a fall +of about one hundred and five feet, which was brought into use +systematically very soon after that at Lowell, and could furnish +about fourteen thousand horse power during the usual working hours, +but the works are so arranged that part of the power is not +available at present.</p> + +<p>At Manchester, New Hampshire, the present works were commenced +in 1835. The Merrimack River at this point has a fall of about +fifty-two feet, and furnishes, at a minimum, about ten thousand +horse power during the usual working hours.</p> + +<p>At Lawrence, Massachusetts, the Essex Co. built a dam across the +Merrimack River, commencing in 1845, and making a fall of about +twenty-eight feet, and a minimum power, during the usual working +hours, of about ten thousand horse power.</p> + +<p>At Holyoke, Massachusetts, the Hadley Falls Co. commenced their +works about 1845, for developing the power of the Connecticut River +at that point, where there is a fall of about fifty feet, and at a +minimum, about seventeen thousand horse power during the usual +working hours.</p> + +<p>At Lewiston, Maine, the fall in the Androscoggin River is about +fifty feet; its systematic development was commenced about 1845, +and with the improvement of the large natural reservoirs at the +head waters of the river, now in progress, it is expected that a +minimum power, during the usual working hours, of about eleven +thousand horse power will be obtained.</p> + +<p>At Birmingham, Connecticut, the Housatonic Water Co. have +developed the water power of the Housatonic River by a dam, giving +twenty-two feet fall, furnishing at a minimum about one thousand +horse power during the usual working hours.</p> + +<p>The Dundee Water and Land Co., about 1858, developed the power +of the Passaic River, at Passaic, New Jersey, where there is a fall +of about twenty-two feet, giving a minimum power, during the usual +working hours, of about nine hundred horse power.</p> + +<p>The Turners Falls Co., in 1866, commenced the development of the +power of the Connecticut River at Turners Falls, Massachusetts, by +building a dam on the middle fall, which is about thirty-five feet, +and furnishes a minimum power, during the usual working hours, of +about ten thousand horse power.</p> + +<p>I have named the above water powers as being developed in a +systematic manner from their inception, and of which I have been +able to obtain some data. In the usual process of developing a +large water power, a company is formed, who acquire the title to +the property, embracing the land necessary for the site of the +town, to accommodate the population which is sure to gather around +an improved water power. The dam and canals or races are +constructed, and mill sites, with accompanying rights to the use of +the water, are granted, usually by perpetual leases subject to +annual rents. This method of developing water power is distinctly +an American idea, and the only instance where it has been attempted +abroad, that I know of, is at Bellegarde in France, where there is +a fall in the Rhone of about thirty-three feet. Within the last few +years works have been constructed for its development, furnishing a +large amount of power, but from the great outlay incurred in +acquiring the titles to the property, and other difficulties, it +has not been a financial success.</p> + +<p>The water powers I have named are but a small fraction of the +whole amount existing in the United States and the adjoining +Dominion of Canada. There is Niagara, with its two or three +millions of horse power; the St. Lawrence, with its succession of +falls from Lake Ontario to Montreal; the Falls of St. Antony, at +Minneapolis; and many other falls, with large volumes of water, on +the upper Mississippi and its branches. It would be a long story to +name even the large water powers, and the smaller ones are almost +innumerable. In the State of Maine a survey of the water power has +recently been made, the result, as stated in the official report, +being "between one and two millions of horse power," part of which +will probably not be available. There is an elevated region in the +northern part of the South Atlantic States, exceeding in area one +hundred thousand square miles, in which there is a vast amount of +water power, and being near the cotton fields, with a fine climate, +free from malaria, its only needs are railways, capital, and +population, to become a great manufacturing section.</p> + +<p>The design and construction of the works for developing a large +water power, together with the necessary arrangements for utilizing +it and providing for its subdivision among the parties entitled to +it according to their respective rights, affords an extensive field +for civil engineers; and in view of the vast amount of it yet +undeveloped, but which, with the increase of population and the +constantly increasing demand for mechanical power as a substitute +for hand labor, must come into use, the field must continue to +enlarge for a long time to come.</p> + +<p>There are many cases in which the power of a waterfall can be +made available by means of compressed air more conveniently than by +the ordinary motors. The fall may be too small to be utilized by +the ordinary motors; the site where the power is wanted may be too +distant from the waterfall; or it may be desired to distribute the +power in small amounts at distant points.[1] A method of +compressing air by means of a fall of water has been devised by Mr. +Joseph P. Frizell, C.E., of St. Paul, Minnesota, which, from the +extreme simplicity of the apparatus, promises to find useful +applications. The principle on which it operates is, by carrying +the air in small bubbles in a current of water down a vertical +shaft, to the depth giving the desired compression, then through a +horizontal passage in which the bubbles rise into a reservoir near +the top of this passage, the water passing on and rising in another +vertical or inclined passage, at the top of which it is discharged, +of course, at a lower level than it entered the first shaft.</p> + +<p>[Footnote 1: <i>Journal of the Franklin Institute</i> for +September, 1877.]</p> + +<p>The formation at waterfalls is usually rock, which would enable +the passages and the reservoir for collecting the compressed air to +be formed by simple excavations, with no other apparatus than that +required to charge the descending column of water with the bubbles +of air, which can be done by throwing the water into violent +commotion at its entrance, and a pipe and valve for the delivery of +the air from the reservoir.</p> + +<p>The transfer of power by electricity is one of the problems now +engaging the attention of electricians, and it is now done in +Europe in a small way. Sir William Thomson stated in evidence +before an English parliamentary committee, two years ago, that he +looked "forward to the Falls of Niagara being extensively used for +the production of light and mechanical power over a large area of +North America," and that a copper wire half an inch in diameter +would transmit twenty-one thousand horse power from Niagara to +Montreal, Boston, New York, or Philadelphia. His statements appear +to have been based on theoretical considerations; but there is no +longer any doubt as to the possibility of transferring power in +this manner--its practicability for industrial purposes must be +determined by trial. Dr. Paget Higgs, a distinguished English +electrician, is now experimenting on it in the City of New +York.</p> + +<p>Great improvements in reaction water wheels have been made in +the United States within the last forty years. In the year 1844, +the late Uriah Atherton Boyden, a civil engineer of Massachusetts, +commenced the design and construction of Fourneyron turbines, in +which he introduced various improvements and a general perfection +of form and workmanship, which enabled a larger percentage of the +theoretical power of the water to be utilized than had been +previously attained. The great results obtained by Boyden with +water wheels made in his perfect manner, and, in some instances, +almost regardless of cost, undoubtedly stimulated others to attempt +to approximate to these results at less cost; and there are now +many forms of wheel of low cost giving fully double the power, with +the same consumption of water, that was obtained from most of the +older forms of wheels of the same class.</p> + +<h3>ANCHOR ICE.</h3> + +<p>A frequent inconvenience in the use of water power in cold +climates is that peculiar form of ice called anchor or ground ice. +It adheres to stones, gravel, wood, and other substances forming +the beds of streams, the channels of conduits, and orifices through +which water is drawn, sometimes raising the level of water courses +many feet by its accumulation on the bed, and entirely closing +small orifices through which water is drawn for industrial +purposes. I have been for many years in a position to observe its +effects and the conditions under which it is formed.</p> + +<p>The essential conditions are, that the temperature of the water +is at its freezing point, and that of the air below that point; the +surface of the water must be exposed to the air, and there must be +a current in the water.</p> + +<p>The ice is formed in small needles on the surface, which would +remain there and form a sheet if the surface was not too much +agitated, except for a current or movement in the body of water +sufficient to maintain it in a constant state of intermixture. Even +when flowing in a regular channel there is a continued interchange +of position of the different parts of a stream; the retardation of +the bed causes variations in the velocity, which produce whirls and +eddies and a general instability in the movement of the water in +different parts of the section--the result being that the water at +the bottom soon finds its way to the surface, and the reverse. I +found by experiments on straight canals in earth and masonry that +colored water discharged at the bottom reached the surface at +distances varying from ten to thirty times the depth.[1] In natural +water courses, in which the beds are always more or less irregular, +the disturbance would be much greater. The result is that the water +at the surface of a running stream does not remain there, and when +it leaves the surface it carries with it the needles of ice, the +specific gravity of which differs but little from that of the +water, which, combined with their small size, allows them to be +carried by the currents of water in any direction. The converse +effect takes place in muddy streams. The mud is apparently held in +suspension, but is only prevented from subsiding by the constant +intermixture of the different parts of the stream; when the current +ceases the mud sinks to the bottom, the earthy particles composing +it, being heavier than water, would sink in still water in times +inversely proportional to their size and specific gravity. This, I +think, is a satisfactory explanation of the manner in which the ice +formed at the surface finds its way to the bottom; its adherence to +the bottom, I think, is explained by the phenomenon of +<i>regelation</i>, first observed by Faraday; he found that when +the wetted surfaces of two pieces of ice were pressed together they +froze together, and that this took place under water even when +above the freezing point. Professor James D. Forbes found that the +same thing occurred by mere contact without pressure, and that ice +would become attached to other substances in a similar manner. +Regelation was observed by these philosophers in carefully arranged +experiments with prepared surfaces fitting together accurately, and +kept in contact sufficiently long to allow the freezing together to +take place. In nature these favorable conditions would seldom occur +in the masses of ice commonly observed, but we must admit, on the +evidence of the recorded experiments, that, under particular +circumstances, pieces of ice will freeze together or adhere to +other substances in situations where there can be no abstraction of +heat.</p> + +<p>[Footnote 1: Paper clx., in the Transactions of the Society, +1878, vol. vii., pages 109-168.]</p> + +<p>When a piece of ice of considerable size comes in contact under +water with ice or other substance, it would usually touch in an +area very small in proportion to its mass, and other forces acting +upon it, and tending to move it, would usually exceed the freezing +force, and regelation would not take place. In the minute needles +formed at the surface of the water the tendency to adhere would be +much the same as in larger masses touching at points only, while +the external forces acting upon them would be extremely small in +proportion, and regelation would often occur, and of the immense +number of the needles of ice formed at the surface enough would +adhere to produce the effect which we observe and call anchor ice. +The adherence of the ice to the bed of the stream or other objects +is always downstream from the place where they are formed; in large +streams it is frequently many miles below; a large part of them do +not become fixed, but as they come in contact with each other, +regelate and form spongy masses, often of considerable size, which +drift along with the current, and are often troublesome impediments +to the use of water power.</p> + +<p>Water powers supplied directly from ponds or rivers, or canals +frozen over for along distance immediately above the places from +which the water is drawn, are not usually troubled with anchor ice, +which, as I have stated, requires open water, upstream, for its +formation.</p> + +<hr> +<p><a name="33"></a></p> + +<h2>A PAIR OF COTTAGES.</h2> + +<p>This drawing has been admitted into the Exhibition of the Royal +Academy this year. The cottages are of red brick, tiled roof, white +woodwork, as usual, rough-cast in the gables; but they are not +built yet. Design of Arthur Cawston.--<i>Building News</i>.</p> + +<p class="ctr"><a href="images/11a.png"><img src= +"images/11a_th.png" alt=""></a></p> + +<p class="ctr">SUGGESTIONS IN ARCHITECTURE.--A PAIR OF ENGLISH +COTTAGES.--BY A.<br> +CAWSTON.</p> + +<hr> +<p><a name="22"></a></p> + +<h2>DELICATE SCIENTIFIC INSTRUMENTS.</h2> + +<h3>By EDGAR L. LARKIN, New Windsor Observatory, New Windsor, +Illinois.</h3> + +<p>Within the past five years, scientific men have surpassed +previous efforts in close measurement and refined analysis. By +means of instruments of exceeding delicacy, processes in nature +hitherto unknown, are made palpable to sense. Heat is found in ice, +light in seeming darkness, and sound in apparent silence. It seems +that physicists and chemists have almost if not quite reached the +ultimate atoms of matter. The mechanism must be sensitive, as such +properties of matter as heat, light, electricity, magnetism, and +actinism, are to be handled, caused to vanish and reappear, +analyzed and measured. With such instruments nature is scrutinized, +revealing new properties, strange motions, vibrations, and +undulations. Throughout the visible universe, the faintest +pulsations of atoms are detected, and countless millions of +infinitely small waves, bearing light, heat, and sound, are +discovered and their lengths determined. Refined spectroscopic +analysis of light is now made so that when any material burns, no +matter what its distance, its spectrum tells what substance is +burning. When any luminous body appears, it can be told whether it +is approaching or receding, or whether it shines by its own or +reflected light; whence it is seen that rays falling on earth from +a flight of a hundred years, are as sounding lines dropped in the +appalling depths of space. We wish to describe a few of these +intricate instruments, and mention several far-reaching discoveries +made by their use; beginning with mechanism for the manipulation of +light. Optics is based on the accidental discovery that a piece of +glass of certain shape will draw light to a focus, forming an image +of any object at that point. The next step was in learning that +this image can be viewed with a microscope, and magnified; thus +came the telescope revealing unheard of suns and galaxies. The +first telescopes colored everything looked at, but by a hundred +years of mathematical research, the proper curvature of objectives +formed of two glasses was discovered, so that now we have perfect +instruments. Great results followed; one can now peer into the +profound solitudes of space, bringing to view millions of stars, +requiring light 5,000 years to traverse their awful distance, and +behold suns wheeling around suns, and thousands of nebulæ, or +agglomerations of stars so distant as to send us confused light, +appearing like faint gauze like structures in measureless voids. +The modern telescope has astonishing power, thus: When Mr. Clark +finished the great twenty-six-inch equatorial, now at Washington, +he tested its seeing properties. A photographic calligraph, whose +letters were so fine as to require a microscope to see them, was +placed at a distance of three hundred feet. Mr. Clark turned the +great eye upon the invisible thing and read the writing with ease. +But a greater feat than this was accomplished by the same +instrument-- the discovery of the two little moons of Mars, by +Prof. Asaph Hall, in 1877. They are so small as to be incapable of +measurement by ordinary means, but with an ingenious photometer +devised by Prof. Pickering of Harvard College, he determined the +outer satellite to be six and the inner seven miles in diameter. +The discovery of these minute bodies seems past belief, and will +appear more so, when it is told that the task is equal to that of +viewing a luminous ball two inches in diameter suspended above +Boston, by the telescope situated in the city of New York. (Newcomb +and Holden's Astronomy, p. 338.)</p> + +<p>Phobos, the nearest moon, is only 4,000 miles from the surface +of Mars, and is obliged to move with such great velocity to prevent +falling, that it actually makes a circuit about its primary in only +seven hours and thirty-eight minutes. But Mars turns on <i>its</i> +axis in twenty-four hours and thirty-seven minutes, so the moon +goes round three times, while Mars does once, hence it rises in the +west and sets in the east, making one day of Mars equal three of +its months. This moon changes every two hours, passing all phases +in a single martial night; is anomalous in the solar system, and +tends to subvert that theory of cosmic evolution wherein a rotating +gaseous sun cast off concentric rings, afterward becoming planets. +Astronomers were not satisfied with the telescope; true, they +beheld the phenomena of the solar system; planets rotating on axes, +and satellites revolving about them. They saw sunspots, +faculæ, and solar upheaval; watched eclipses, transits, and +the alternations of summer and winter on Mars, and detected the +laws of gravity and motion in the system to which the earth +belongs. They then devised the micrometer. This is a complex +mechanism placed in the focus of a telescope, and by its use any +object, providing it shows a disk, no matter what its distance, can +be measured. It consists of spider webs set within a graduated +metallic circle, the webs movable by screws, and the whole +instrument capable of rotating about the collimation axis of the +telescope. The screw head is a circle ruled to degrees and minutes, +and turns in front of a fixed vernier in the field of a reading +microscope. One turn of the screw moves the web a certain number of +seconds; then as there are 360° in a circle, +one-three-hundred-and-sixtieth of a turn moves the web +one-three-hundred and-sixtieth of the amount, and so on. Thus, when +two stars are seen in the field, one web is moved by the screw +until the fixed line and the movable one are parallel, each +bisecting a star. By reading with the microscope the number of +degrees turned, the distance apart of the stars becomes known; the +distance being learned, position is then sought; the observance of +which led to one of the greatest discoveries ever made by man. The +permanent line of the micrometer is placed in the line joining the +north and south poles of the heavens, and brought across one of the +stars; the movable web is then rotated until it bisects the other, +and then the angle between the webs is recorded. Double stars are +thus measured, first in distance, and second, their position. After +this, if any movement of the stars takes place, the tell tale +micrometer at once detects it.</p> + +<p>In 1780, Sir Wm. Herschel measured double stars and made +catalogues with distances and positions. Within twenty years, he +startled intellectual man with the statement that many of the fixed +stars actually move--one great sun revolving around another, and +both rotating about their common center of gravity. If we look at a +double star with a small telescope, it looks just like any other; +using a little larger glass, it changes appearance and looks +elongated; with a still better telescope, they become distinctly +separated and appear as two beautiful stars whose elements are +measured and carefully recorded, in order to see if they move. +Herschel detected the motion of fifty of these systems, and +revolutionized modern astronomy. Astronomers soared away from the +little solar system, and began a minute search throughout the whole +sidereal heavens. Herschel's catalogue contained four hundred +double suns, only fifty of which were known to be in revolution. +Since then, enormous advance has been made. The micrometer has been +improved into an instrument of great delicacy, and the number of +doubles has swelled to ten thousand; six hundred and fifty of them +being known to be binary, or revolving on orbits--Prof. S. W. +Burnham, the distinguished young astronomer of the Dearborn +Observatory, Chicago, having discovered eight hundred within the +last eight years. This discovery implies stupendous motion; every +fixed star is a sun like our own, and we can imagine these wheeling +orbs to be surrounded by cool planets, the abode of life, as well +as ours. If the orbit of a binary system lies edgewise toward us, +then one star will hide the other each revolution, moving across it +and appearing on the other side. Several instances of this motion +are known; the distant suns having made more than a complete +circuit since discovery, the shortest periodic time known being +twenty-five years.</p> + +<p>Wonderful as was this achievement of the micrometer, one not +less surprising awaited its delicate measurement. If one walks in a +long street lighted with gas, the lights ahead will appear to +separate, and those in the rear approach. The little spider lines +have detected just such a movement in the heavens. The stars in +Hercules are all the time growing wider apart, while those in +Argus, in exactly the opposite part of the Universe, are steadily +drawing nearer together. This demonstrates that our sun with his +stately retinue of planets, satellites, comets, and meteorites, all +move in grand march toward the constellation Hercules. The entire +universe is in motion. But these revelations of the micrometer are +tame compared with its final achievement, the discovery of +parallax.</p> + +<p>This means difference of direction, and the parallax of a star +is the difference of its direction when viewed at intervals of six +months. Astronomers observe a star to-day with a powerful telescope +and micrometer; and in six months again measure the same star. But +meanwhile the earth has moved 183,000,000 miles to the east, so +that if the star has changed place, this enormous journey caused +it, and the change equals a line 91,400,000 miles long as viewed +from the star. For years many such observations were made; but +behold the star was always in the same place; the whole distance of +the sun having dwindled down to the diameter of a pin point in +comparison with the awful chasm separating us from the stars. +Finally micrometers were made that measured lines requiring 100,000 +to make an inch; and a new series of observations begun, crowning +the labors of a century with success. Finite man actually told the +distance of the starry hosts and gauged the universe.</p> + +<p>When the parallax of any object is found, its distance is at +once known, for the parallax is an arc of a circle whose radius is +the distance. By an important theorem in geometry it is learned, +that when anything subtends an angle of one second its distance is +206,265 times its own diameter. The greatest parallax of any star +is that of Alpha Centauri--nine-tenths of a second; hence it is +more than 206,265 times 91,400,000 miles--the distance of the +sun--away, or twenty thousand billions of miles. This is the +distance of the nearest fixed star, and is used as a standard of +reference in describing greater depths of space. This is not all +the micrometer enables man to know, When the distance separating +the earth from two celestial bodies that revolve is learned, the +distance between the two orbs becomes known. Then the period of +revolution is learned from observation, and having the distance and +time, then their velocity can be determined. The distance and +velocity being given, then the combined weights of both suns can be +calculated, since by the laws of gravity and motion it is known how +much weight is required to produce so much motion in so much time, +at so much distance, and thus man weighs the stars. If the density +of these bodies could be ascertained, their diameters and volumes +would be known, and the size of the fixed stars would have been +measured. Density can never be exactly learned; but strange to say, +photometers measure the quantity of light that any bright body +emits; hence the stars cannot have specific gravity very far +different from that of the sun, since they send similar light, and +in quantity obeying the law wherein light varies inversely as the +squares of distance. Therefore, knowing the weight and having close +approximation to density, the sizes of the stars are nearly +calculated. The conclusion is now made that all suns within the +visible universe are neither very many times larger nor smaller +than our own. (Newcomb and Holden's Astronomy, p. 454.)</p> + +<p>Another result followed the use of the micrometer: the detection +of the proper motion of the stars. For several thousand years the +stars have been called "fixed," but the fine rulings of the filar +micrometer tell a different story. There are catalogues of several +hundred moving stars, whose motion is from one-half second to eight +seconds annually. The binary star, Sixty-one Cygni, the nearest +north of the equator, moves eight seconds every year, a +displacement equal in three hundred and sixty years to the apparent +diameter of the moon. The fixed stars have no general motion toward +any point, but move in all directions.</p> + +<p>Thus the micrometer revealed to man the magnitude and general +structure, together with the motions and revolutions of the +sidereal heavens. Above all, it demonstrated that gravity extends +throughout the universe. Still the longings of men were not +appeased; they brought to view invisible suns sunk in space, and +told their weight, yet the thirst for knowledge was not quenched. +Men wished to know what all the suns are made of, whether of +substances like those composing the earth, or of kinds of matter +entirely different. Then was devised the spectroscope, and with it +men audaciously questioned nature in her most secluded recesses. +The basis of spectroscopy is the prism, which separates sunlight +into seven colors and projects a band of light called a spectrum. +This was known for three hundred years, and not much thought of it +until Fraunhofer viewed it with a telescope, and was surprised to +find it filled with hundreds of black lines invisible to the +unaided eye. Could it be possible that there are portions of the +solar surface that fail to send out light? Such is the fact, and +then began a twenty years' search to learn the cause. The lines in +the solar spectrum were unexplained until finally metals were +vaporized in the intense heat of the electric arc and the light +passed through a spectroscope, when behold the spectra of metals +were filled with bright lines in the same places as were the dark +lines in the spectrum of the sun. Another step: if when metals are +volatilized in the arc, rays of light from the sun are passed +through the vapor and allowed to enter the spectroscope, a great +change is wrought; a reversal takes place, and the original black +bands reappear. A new law of nature was discovered, thus: "Vapors +of all elements absorb the same rays of light which they emit when +incandescent." Every element makes a different spectrum with lines +in different places and of different widths. These have been +memorized by chemists, so that when an expert having a spectroscope +sees anything burn he can tell what it is as well as read a printed +page. Men have learned the alphabet of the universe, and can read +in all things radiating light, the constituent elements. The black +lines in the solar spectrum are there because in the atmosphere of +the sun exist vapors of metals, and the light from the liquid +metals below is unable to pass through and reach the earth, being +absorbed kind for kind. Gaseous iron sifts out all rays emitted +from melted iron, and so do the vapors of all other elements in the +sun, radiating light in unison with their own. Sodium, iron, +calcium, hydrogen, magnesium, and many other substances are now +known to be incandescent in the sun and stars; and the results of +the developments of the spectroscope may be summed up in the +generalization that all bodies in the universe are composed of the +same substance the earth is.</p> + +<p>The sun is subject to terrific hurricanes and cyclones, as well +as explosions, casting up jets to the height of 200,000 miles. In +the early days of spectroscopy these protuberances could only be +seen at a time of a total solar ellipse, and astronomers made long +journeys to distant parts of the earth to be in line of totality. +Now all is changed. Images of the sun are thrown into the +observatory by an ingenious instrument run by clockwork, and called +a heliostat. This is set on the sun at such an angle as to throw +the solar image into the objective of the telescope placed +horizontally in a darkened observatory, and the pendulum ball set +in motion, when it will follow the sun without moving its image, +all day if desired. At the eye end of the telescope is attached the +spectroscope and the micrometer, and the whole set of instruments +so adjusted that just the edge of the sun is seen, making a half +spectrum. The other half of the spectroscope projects above the +solar limb, and is dark, so if an explosion throws up liquid jets, +or flames of hydrogen, the astronomer at once sees them and with +the micrometer measures their height before they have time to fall. +And the spectrum at once tells what the jets are composed of, +whether hydrogen, gaseous iron, calcium, or anything else. Prof. C. +A. Young saw a jet of hydrogen ascend a distance of 200,000 miles, +measured its height, noted its spectrum and timed its ascent by a +chronometer all at once, and was astonished to find the velocity +one hundred and sixty miles per second--eight times faster than the +earth flies on its orbit. By these improvements solar hurricanes, +whirlpools, and explosions can be seen from any physical +observatory on clear days.</p> + +<p>The slit of the spectroscope can be moved anywhere on the disk +of the sun; so that if the observer sees a tornado begin, he moves +the slit along with it, measures the length of its tract and +velocity. With the telescope, micrometer, heliostat, and +spectroscope came desire for more complex instruments, resulting in +the invention of the photoheliograph, invoking the aid of +photography to make permanent the results of these exciting +researches. This mechanism consists of an excessively sensitive +plate, adjusted in the solar focus of the telespectroscope. In +front of the plate in the camera is a screen attached to a spring, +and held closed by a cord. The eye is applied to the spectroscopic +end of the complex arrangement to watch the development of solar +hurricanes.</p> + +<p>Finally an appalling outburst occurs; the flames leap higher and +higher, torn into a thousand shreds, presenting a scene that +language is powerless to describe. When the display is at the +height of its magnificence, the astronomer cuts the cord; the slide +makes an exposure of one-three thousandth part of a second, and an +accurate photograph is taken. The storm all in rapid motion is +petrified on the plate; everything is distinct, all the surging +billows of fire, boilings, and turbulence are rendered motionless +with the velocity of lightning.</p> + +<p>At Meudon, in France, M. Janssen takes these instantaneous +photographs of the sun, thirty inches in diameter, and afterward +enlarges them to ten feet; showing scenes of fiery desolation that +appalls the human imagination. (See address of Vice President +Langley, A. A. A. S., Proceedings Saratoga Meeting, p. 56.) This +huge photograph can be viewed in detail with a small telescope and +micrometer, and the crests of solar waves measured. Many of these +billows of fire are in dimensions every way equal in size to the +State of Illinois. Binary stars are photographed so that in time to +come they can be retaken, when if they have moved, the precise +amount can be measured.</p> + +<p>Another instrument is the telepolariscope, to be attached to a +telescope. It tells whether any luminous body sends us its own, or +reflected light. Only one comet bright enough to be examined has +appeared since its perfection. This was Coggia's, and was found to +reflect solar from the tail, and to radiate its own light from the +nucleus.</p> + +<p>Still another intricate instrument is in use, the thermograph, +that utilizes the heat rays from the sun, instead of the light. It +takes pictures by heat; in other words, it sees in the dark; brings +invisible things to the eye of man, and is used in astronomical and +physical researches wherein undulations and radiations are +concerned. And now comes the magnetometer, to measure the amount of +magnetism that reaches the earth from the sun. It points to zero +when the magnetic forces of the earth are in equilibrium, but let a +magnetic storm occur anywhere in the world and the pointer will +move by invisible power. It detects a close relation between the +magnetism of the earth and sun. The needle is deflected every time +a solar disturbance takes place. At Kew, England, an astronomer was +viewing the sun with a telescope and observed a tongue of flame +dart across a spot whose diameter was thirty-three thousand seven +hundred miles. The magnetometer was violently agitated at once, +showing that whatever magnetism may be, its influence traversed the +distance of the sun with a velocity greater than that of light.</p> + +<p>Not less remarkable is the new instrument, the thermal balance, +devised by Prof. S. P. Langley, Pittsburgh. It will measure the +one-fifty-thousandth part of a degree of heat, and consists of +strips of platinum one-thirty-second of an inch wide and one-fourth +of an inch long; and so thin that it requires fifty to equal the +thickness of tissue paper, placed in the circuit of electricity +running to a galvanometer. "When mounted in a reflected telescope +it will record the heat from the body of a man or other animal in +an adjoining field, and can do so at great distances. It will do +this equally well at night, and may be said, in a certain sense, to +give the power of seeing in the dark." (<i>Science</i>, issue of +Jan. 8,1881, p. 12.) It is expected to reveal great facts +concerning the heat of the stars.</p> + +<p>Indeed, the thermopile in the hands of Lockyer has already made +palpable the heat of the fixed stars. He placed the little +detective in the focus of a telescope and turned it on Arcturus. +"The result was this, that the heat received from Arcturus, when at +an altitude of 55°, was found to be just equal to that received +from a cube of boiling water, three inches across each side, at the +distance of four hundred yards; and the heat from Vega is equal to +that from the same cube at six hundred yards." (Lockyer's Star +Gazing, p. 385.) Thus that inscrutable mode of force heat traverses +the depths of space, reaches the earth, and turns the delicate +balance of the thermopile. Another discovery was made with the +spectroscope; thus, if a boat moves up a river, it will meet more +waves than will strike it if going down stream. Light is the +undulation of waves; hence if the spectroscope is set on a star +that is approaching the earth, more waves will enter than if set on +a receding star, which fact is known by displacement of lines in +the spectroscope from normal positions. It is found that many fixed +stars are approaching, while others are moving away from the solar +system.</p> + +<p>We cannot note the researches of Edison, Lockyer, or Tyndall, +nor of Crookes, who has seemingly reached the molecules whence the +universe is composed.</p> + +<p>The modern observatory is a labyrinth of sensitive instruments; +and when any disturbance takes place in nature, in heat, light, +magnetism, or like modes of force, the apparatus note and record +them.</p> + +<p>Men are by no means satisfied. Insatiable thirst to know more is +developing into a fever of unrest; they are wandering beyond the +limits of the known, every day a little farther. They survey space, +and interrogate the infinite; measure the atom of hydrogen and +weigh suns. Man takes no rest, and neither will he until he shall +have found his own place in the chain of nature.--<i>Kansas +Review</i>.</p> + +<hr> +<p><a name="23"></a></p> + +<h2>THE FUTURE DEVELOPMENT OF ELECTRICAL APPLIANCES.</h2> + +<p>Prof. J. Perry lately delivered a lecture on this subject at the +Society of Arts, London, which contains in an epitomized form the +salient points of the hopes and fears of the more sanguine spirits +of the electrical world. Prof. Perry is one of the two professors +who have been dubbed the "Japanese Twins," and whose insatiate love +of work induced one of our most celebrated men of science to say +that they caused the center of experimental research to tend toward +Tokyo instead of London. Professors Ayrton and Perry have for some +time been again resident in England, but it is evident that they +did not leave any of their energy in Japan, for those who know them +intimately, know that they are pursuing numerous original +investigations, and that so soon as one is finished, another is +commenced. It would have been difficult then to have found an abler +exponent of the future of electricity.</p> + +<p>Prof. Perry, after referring to what might have been said of the +great things physical science has done for humanity, plunged into +his subject. The work to be done was vast, and the workers +altogether out of proportion to the task.</p> + +<p>The methods of measurement of electricity are not generally +understood. Perhaps when electricity is supplied to every house in +the city at a certain price per horse power, and is used by private +individuals for many different purposes, this ignorance will +disappear. Electrical energy is obtained in various ways, but the +generators get heated; and one great object of inventors is to +obtain from machines as much as possible electrical energy of the +energy in the first place supplied to such machine. The lecturer +called particular attention to the difference between electricity +and electrical energy, and attempted to drive home the fundamental +conceptions of electrical science by the analogies derivable from +hydraulics. A miller speaks not only of quantity of water, but also +of head of water. The statement then of quantity of electricity is +insufficient, except we know the electrical property analogous to +head of water, and which is termed electrical potential. A small +quantity of electricity of high potential is similar to a small +quantity of water at high level. The analogies between water and +electricity were collected in the form of a table shown on a wall +sheet as follows:</p> + +<pre> +We Want to Use Water. We Want to Use Electricity. +<br> +1. Steam pump burns coal, 1. Generator burns zinc, or +and lifts water to a higher uses mechanical power, and +level. lifts electricity to a higher + level or potential. +<br> +2. Energy available is 2. Energy available is +amount of water lifted x amount of electricity x difference +difference of level. of potential. +<br> +3. If we let all the water 3. If we let all the electricity +flow away through channel flow through a wire from one +to lower level without doing screw of our generator to the +work, its energy is all other without doing work, all +converted into heat because the electrical energy is +of frictional resistance of converted into heat because of +pipe or channel. resistance of wire. +<br> +4. If we let water work a 4. If we let our electricity +hoist as well as flow through work a machine as well as +channels, less water flows flow through wires, less flows +than before, less power is than before, less power is +wasted in friction. wasted through the resistance + of the wire. +<br> +5. However long and narrow 5. However long and thin +may be the channels, the wires may be, electricity +water maybe brought from may be brought from any distance +distance, however great, however great, to give +to give out almost all its out almost all its original +original energy to a hoist. energy to a machine. This requires +This requires a great head a great difference of +and small quantity of water. potentials and a small current. +</pre> + +<p>The difference between potential and electro-motive force was +explained thus: "difference of potential" is analogous with +"difference of pressure" or "head" of water, howsoever produced; +whereas electromotive force is analogous with the difference of +pressure before and behind a slowly moving piston of the pump +employed by an unfortunate miller to produce his water supply. +Electricians have very definite ideas upon the subject they are +working at, and especial attention is paid to the measurements on +which their work depends. Examples of these measurements were shown +by the following tables on wall sheets:</p> + +<pre> +ELECTRICAL MAGNITUDES (SOME RATHER APPROXIMATE). +<br> +Resistance of + One yard of copper wire, one-eighth + of an inch diameter...............................0.002 ohms. + One mile ordinary iron telegraph wire, .........10 to 20 " + Some of our selenium cells ............. 40 to 1,000,000 " + A good telegraph insulator ........... 4,000,000,000,000 " +<br> +Electro-motive force of + A pair of copper-iron junctions at a + difference of temperature of 1 deg. Fah......... =0.0000 volt. + Contact of zinc and copper ..................... =0.75 " + One Daniell's cell ............................. =1.1 " + Mr. Latimer Clark's standard cell .............. =1.45 " + One of Dr. De la Hue's batteries ...... =11,000 " + Lightning flashes probably many millions of volts. +</pre> + +<pre> +Current measured by us in some experiments: +<br> + Using electrometer....... = almost infinitely small + currents. + Using delicate galvanometer =0.00,000,000,040 weber. + Current received from Atlantic + cable, when 25 words per minute + are being sent ................ = 0.000,001 weber + Current in ordinary land telegraph + lines ......................... = 0.003 weber + Current from dynamo machine.... = 5 to 100 weber +</pre> + +<p>In any circuit, <i>current</i> in webers = <i>electro-motive +force</i> in volts / <i>resistance</i> in ohms.</p> + +<h3>RATE OF PRODUCTION OF HEAT, CALCULATED IN THE SHAPE OF +HORSE-POWER.</h3> + +<p>In the whole of a circuit=<i>current</i> in webers x +<i>electro-motive force</i> in volts / 746. In any part of +circuit=<i>current</i> in webers x <i>difference of potential</i> +at the two ends of the part of the circuit in question / 746. Or, +=square of current in webers x resistance of the part in ohms / +746.</p> + +<p>If there are a number of generators of electricity in a circuit, +whose electromotive forces in volts are E<sub>1</sub>, +E<sub>2</sub>, etc., and if there are also opposing electro-motive +forces. F<sub>1</sub>, F<sub>2</sub>, etc., volts, and if C is the +current in webers, R the whole resistance of the current in ohms, P +the total horse-power taken at the generators, Q the total +horse-power converted into some other form of energy, and given out +at the places where there are opposing electro-motive forces, H the +total horse-power wasted in heat, because of resistance, then:</p> + +<p><img src="images/tex1.png" align="middle" alt= +"C = \frac{(E_1+E_2+\text{etc.})-(F_1+F_2+\text{etc.})}{R}"></p> + +<p><img src="images/tex2.png" align="middle" alt= +"\frac{C}{746}(E_1+E_2+\text{etc.});\ Q = \frac{C}{746}(F_1+F_2+\text{etc.})"> +</p> + +<p><img src="images/tex3.png" align="middle" alt= +"H = \frac{C^2 R}{746}."></p> + +<p>The lifting power of an electro-magnet of given volume is +proportional to the heat generated against resistance in the wire +of the magnet.</p> + +<p>The future of many electrical appliances depends on how general +is the public comprehension of the lessons taught by these wall +sheets. If a few capitalists in London would only spend a few days +in learning thoroughly what these mean, electrical appliances of a +very distant future would date from a few months hence.</p> + +<p>A number of experiments were shown, in some of which electrical +energy was converted into heat, in others into sound, in others +into work. At this part of the lecture reference was made to the +work of Prof. Ayrton and his pupils at Cowper street (City and +Guilds of London Institute Classes). They measure (1) the gas +consumed by the engine, (2) the horse-power given to the dynamo +machine, (3) the current in the circuit in webers, and (4) the +resistance of the circuit. Thus exact calculations can now be made +as to the horse power expended in any part of the circuit, and the +light given out in any given period by an electric lamp. The +dynamometers used in these measurements were described, but at +present, in some cases, the description given is for various +reasons incomplete, so that we shall take a future opportunity of +writing of these instruments. To measure the light a photometer, +constructed by Profs. Ayrton and Perry, is used, which obviates the +necessity of large rooms, and enables the operator to give the +intensity in a very short period of time. A number of measurements +of the illuminating power of an electric lamp were rapidly made +during the lecture with this photometer. By means of a small dynamo +machine, driven by an electric current generated in the Adelphi +arches, a ventilator, a sewing machine, a lathe, etc., were driven; +in the latter a piece of wood was turned. "What," said the +lecturer, "do these examples show you?" "They show that if I have a +steam-engine in my back yard I can transmit power to various +machines in my house, but if you measured the power given to these +machines you would find it to be less than half of what the engine +driving the outside electrical machine gives out. Further, when we +wanted to think of heating of buildings and the boiling of water, +it was all very well to speak of the conversion of electrical +energy into heat, but now we find that not only do the two +electrical machines get heated and give out heat, but heat is given +out by our connecting wires. We have then to consider our most +important question. Electrical energy can be transmitted to a +distance, and even to many thousands of miles, but can it be +transformed at the distant place into mechanical or any other +required form of energy, nearly equal in amount to what was +supplied? Unfortunately, I must say that hitherto the practical +answer made to us by existing machines is, 'No;' there is always a +great waste due to the heat spoken of above. But, fortunately, we +have faith in the measurements, of which I have already spoken, in +the facts given us by Joule's experiments and formulated in ways we +can understand. And these facts tell us that in electric machines +of the future, and in their connecting wires, there will be little +heating, and therefore little loss. We shall, I believe, at no +distant date, have great central stations, possibly situated at the +bottom of coal-pits where enormous steam engines will drive +enormous electric machines. We shall have wires laid along every +street, tapped into every house, as gas-pipes are at present; we +shall have the quantity of electricity used in each house +registered, as gas is at present, and it will be passed through +little electric machines to drive machinery, to produce +ventilation, to replace stoves and fires, to work apple-parers and +mangles and barbers' brushes, among other things, as well as to +give everybody an electric light."</p> + +<p>It is possible, as Prof. Ayrton first showed in his Sheffield +lecture, that electrical energy can be transmitted through long +distances by means of small wires, and that the opinion that wires +of enormous thickness would be required is erroneous. The +desideratum required was good insulation. He also showed that, +instead of a limiting efficiency of 50 per cent., the only thing +preventing our receiving the whole of our power was the mechanical +friction which occurs in the machines. He showed, in fact, how to +get rid of electrical friction. A machine at Niagara receives +mechanical power, and generates electricity. Call this the +generator. Let there be Wires to another electric machine in New +York, which will receive electricity, and give out mechanical work. +Now this machine, which may be called the motor, produces a back +electromotive force, and the mechanical power given out is +proportional to the back electromotive force multiplied into the +current. The current, which is, of course, the same at Niagara as +at New York, is proportional to the difference of the two +electromotive forces, and the heat wasted is proportional to the +square of the current. You see, from the last table, that we have +the simple proportion: power utilized is to power wasted, as the +back electromotive force of the motor is to the difference between +electromotive forces of generator and motor. This reason is very +shortly and yet very exactly given as follows:</p> + +<p>Let electromotive force of generator be E; of motor F. Let total +resistance of circuit be R. Then if we call P the horse-power +received by the generator at Niagara, Q, the horse-power given out +by motor at New York, that is, utilized; H, the horse-power wasted +as heat in machines and circuit; C, the current flowing through the +circuit:</p> + +<pre> + C=(E-F) / R +<br> + P=E(E-F) / (746 R) +<br> + Q=F(E-F) / (746 R) +<br> + H=(E-F)_2 / (746 R) +<br> + Q:H::F:E-F +</pre> + +<p>The water analogy was again called into play in the shape of a +model for the better demonstration of the problem. The defects in +existing electric machines and the means of increasing the E.M.F. +were discussed, the conclusions pointing to the future use of very +large machines and very high velocities. The future of telephonic +communication received a passing remark, and attention called to +the future of electric railways. The small experiments of Siemens +have determined the ultimate success of this kind of railway. Their +introduction is merely a question of time and capital. The first +cost of electric railways would be smaller than that of steam +railways; the working expenses would also be reduced. The rails +would be lighter, the rolling stock lighter, the bridges and +viaducts less costly, and in the underground railways the +atmosphere would not be vitiated.</p> + +<p>"About two years ago, it struck Professor Ayrton and myself, +when thinking how very faint musical sounds are heard distinctly +from the telephone, in spite of loud noises in the neighborhood, +that there was an application of this principle of recurrent +effects of far more practical importance than any other, namely, in +the use of musical notes for coast warnings in thick weather. You +will say that fog bells and horns are an old story, and that they +have not been particularly successful, since in some states of the +weather they are audible, in others not.</p> + +<p>"Now, it seems to be forgotten by everybody that there is a +medium of communicating with a distant ship, namely, the water, +which is not at all influenced by changes in the weather. At some +twenty or thirty feet below the surface there is exceedingly little +disturbance of the water, although there may be large waves at the +surface. Suppose a large water-siren like this--experiment +shown--is working at as great a depth as is available, off a +dangerous coast, the sound it gives out is transmitted so as to be +heard at exceedingly great distances by an ear pressed against a +strip of wood or metal dipping into the water. If the strip is +connected with a much larger wooden or metallic surface in the +water the sound is heard much more distinctly. Now, the sides of a +ship form a very large collecting surface, and at the distance of +several miles from such a water siren as might be constructed, we +feel quite sure that, above the noise of engines and flapping +sails, above the far more troublesome noise of waves striking the +ship's side, the musical note of the distant siren would be heard, +giving warning of a dangerous neighborhood. In considering this +problem, you must remember that Messrs. Colladon and Sturn heard +distinctly the sound of a bell struck underwater at the distance of +nearly nine miles, the sound being communicated by the water of +Lake Geneva."</p> + +<p>The next portion of the lecture discussed the great value of a +rapid recurrence of effects, the obtaining of sound by means of a +rapid intermission of light rays on selenium joined up in an +electric circuit being instanced as an example. Then recent +experiments on the refractive power of ebonite were detailed--the +rough results tending to give greater weight to Clerk-Maxwell's +electro-magnetic theory of light. The index of refraction of +ebonite was found by Profs. Ayrton and Perry to be roughly 1.7. +Clerk-Maxwell's theory requires that the square of this number +should be equal to the electric specific inductive capacity of the +substance. For ebonite this electric constant varies from 2.2 to +3.5 for different specimens, the mean of which is almost exactly +equal to the square of 1.7.</p> + +<hr> +<p><a name="24"></a></p> + +<h2>RESEARCHES ON THE RADIANT MATTER OF CROOKES AND THE MECHANICAL +THEORY OF ELECTRICITY.</h2> + +<h3>By DR. W. F. GINTL, abstracted by DR. VON GERICHTEN.</h3> + +<p>The author discusses the question whether, according to the +experiments of Crookes, the assumption of an especial fourth state +of aggregation is necessary, or whether the facts may be +satisfactorily explained without such hypothesis? He shows that the +latter alternative is possible with the aid of a mechanical theory +of electricity. If the radiant matter produced in the vacuum is a +phenomenon <i>sui generis,</i> produced by the action of +electricity and heat upon the molecules of gas remaining in the +receiver, it is, in the first place, doubtful to apply to it the +conception of an aggregate condition. The author considers it +impossible to form a clear understanding of the phenomena in +accordance with the theory of Crookes, or to find in the facts any +evidence of the existence of radiant matter. An explanation of the +latter phenomenon is thus given: Particles become separated from +the surface of the substance of the negative pole, they are +repelled, and they move away from the pole with a speed resulting +from the antagonistic forces in a parallel and rectilinear +direction, preserving their speed and their initial path so long as +they do not meet with obstacles which influence their movement. At +a certain density of the gases present in the exhausted space, +these particles, in consequence of the impact of gaseous molecules +more or less opposed to their direction of movement, lose their +velocity after traveling a short distance and soon come to rest. +The more dilute the gas the smaller is the number of the impacts of +the gaseous molecules encountering the molecules of the poles, and +at a certain degree of dilution the repelled polar particles will +be able to traverse the space open to them without any essential +alteration in their speed, the small number of the existing gaseous +molecules being no longer able to retard the molecules of the polar +no their journey through the apparatus. The luminous phenomena of +the Geissler tubes the author supposes to be produced by the +intense blows which the gaseous molecules receive from the polar +molecules flying rapidly through the apparatus. The intensity of +the luminous phenomena will naturally decrease with the number of +the photophorous particles occupying the space. Accordingly in the +experiments of Crookes, on continued rarefaction of the gas, a +condition was reached where a display of light is no longer +perceptible, or can be made visible merely by the aid of +fluorescent bodies. A condition may also appear, as is shown by +Crookes' experiment, with the metallic plate intercalated as +negative pole in the middle of. a Geissler tube, with the positive +poles at the ends. In this case the gaseous molecules are, so to +speak, driven away by the polar particles endowed with an equal +initial velocity, till at a certain distance from the pole the mass +of the gaseous molecules and their speed become so great that a +luminous display begins. In an analogous manner the author explains +the phenomena of phosphorescence which Crookes' elicits by the +action of his radiant matter. In like manner the thermic and the +mechanical effects are most simply explained, according to the +expression selected by Crookes himself, as the results of a +"continued molecular bombardment." The attraction of the so called +radiant matter, regarded as a stream of metallic particles by the +magnet, will not appear surprising.</p> + +<hr> +<p><a name="25"></a></p> + +<h2>ECONOMY OF THE ELECTRIC LIGHT.</h2> + +<p>Mr. W. H. Preece writes to the <i>Journal of Arts</i> as +follows:</p> + +<p>At the South Kensington Museum, very careful observations have +been made on the relative cost of the two systems, <i>i. e.</i>, +gas and electricity. The court lighted is that known as the "Lord +President's" (or the Loan) Court. It is 138 feet long by 114 feet +wide, and has an average height of about 42 feet. It is divided +down the middle lengthwise by a central gallery. There are +cloisters all around it on the ground floor, and the walls above +are decorated in such a way that they do not assist in the +reflection or diffusion of the light. The absence of a ceiling--the +court being sky-lighted--is to some extent compensated for by +drawing the blinds under the sky-lights.</p> + +<p>The experiments commenced about twelve months ago, with eight +lamps only on one side of the court. The system was that of Brush. +The dynamo machine was driven by an eight horse-power Otto gas +engine, supplied by Messrs. Crossley. The comparison with the gas +was so much in favor of electricity, and the success of the +experiment so encouraging, that it was determined to light up the +whole court.</p> + +<p>The gas engine, which was not powerful enough, was replaced by a +14-horse power "semi-portable" steam engine, by Ransomes & Co., +of Ipswich--an engine of sufficient power to drive double the +required number of lights. The dynamo machine is a No. 7 Brush. +There are sixteen lamps in all--eight on each side of the court. +The machine has given no trouble whatever, and it has, as yet, +shown no signs of wear. The lamps were not all good, and it was +found that they required careful adjustment, but when once they +were got to go right they continued to do so, and have, up to the +present, shown no signs of deterioration, although the time during +which they have been in operation is nine months.</p> + +<p>The first outlay has been as follows:</p> + +<pre> +Engine and fixing, including shafting and +belting................................ £420 +Dynamo machine......................... 400 +Lamps, apparatus, and conducting wire . 384 + ------ + £1,204 +</pre> + +<p>The cost of working has been, from June 22, to December 31, +during which period the lights were going on 87 nights for a total +time of 359 hours:</p> + +<pre> + £ s. d. +Carbons............................... 18 9 0 +Oil, etc.............................. 4 11 6 +Coal.................................. 11 14 0 +Wages................................. 34 7 6 + ---------- + £69 2 0 +</pre> + +<p>being at the rate of 3s. 10d. per hour of light.</p> + +<p>Now, the consumption of gas in the court would have been 4,800 +cubic feet per hour, which, at 3s. 4d. per 1,000 cubic feet, would +amount to 16s. per hour, thus showing a saving of working expenses +of 12s. 2d. per hour, or, since the museum is lit up for 700 hours +every year, a total saving at the rate of £426 per annum.</p> + +<p>In estimating the cost as applied to this court, only half the +cost of the engine should be taken, for a second dynamo machine has +lately been added to light up some of the picture galleries, and +the "Life" room of the Art School. The capital outlay should, +therefore, be £994. In making a fair estimate of the annual +cost, we should also allow something for percentage on capital, and +something for wear and tear. Take--</p> + +<pre> + £ s. +5 per cent, on the capital............................. 49 10 +5 per cent, for wear and tear of electrical apparatus.. 39 0 +5 per cent, for depreciation of engines, etc........... 21 0 + ------- + Total.......... £109 10 +</pre> + +<p>leaving a handsome balance to the good of £316 10s. as +against gas. The results of the working, both practically and +financially, have proved to be, at South Kensington, a decided +success.</p> + +<p>I am indebted to Colonel Festing, R.E., who has charge of the +lighting, for these details.</p> + +<p>The same comparison cannot be made at the British Museum, for no +gas was used in the reading-room before the introduction of the +electric light, but the cost of lighting has proved to be 5s. 6d. +per hour--at least one-third of that which would be required for +gas. The system in use at the Museum is Siemens', the engine being +by Wallis and Steevens, of Basingstoke.</p> + +<p>"An excellent example of economic electric lighting, is that of +Messrs. Henry Tate & Sons, sugar refinery, Silvertown. A small +Tangye engine, placed under the supervision of the driver of a +large engine of the works, drives an 'A' size 'Gramme' machine, +which feeds a 'Crompton' 'E' lamp. This is hung at a height of +about 12 feet from the ground in a single story shed, about 80 feet +long, and 50 feet wide, and having an open trussed roof. The light, +placed about midway, lengthways, has a flat canvas frame, forming a +sort of ceiling directly over it, to help to diffuse the +illumination. The whole of the shed is well lit; and a large +quantity of light also penetrates into an adjoining one of similar +dimensions, and separated by a row of columns. The light is used +regularly all through the night, and has been so all through the +winter. Messrs. Tate speak highly of its efficiency. To ascertain +the exact cost of the light, as well as of the gas illumination +which it replaced, a gas-meter was placed to measure the +consumption of the gas through the jets affected; and also the +carbons consumed by the electric illumination were noted. A series +of careful experiments showed that during a winter's night of 14 +hours' duration the illumination by electricity cost 1s. 9d., while +that by gas was 3s. 6d., or 1½d. per hour against 3d. per +hour. To this must be added the greatly increased illumination, +four to five times, given by the electric light, to the benefit of +the work; while this last illuminant also allowed, during the +process of manufacture of the sugar, the delicate gradations of +tint to be detected; and so to avoid those mistakes, sometimes +costly ones, liable to arise through the yellow tinge of gas +illumination. This alone would add much to the above-named economy, +arising from the use of electric illumination in sugar works."</p> + +<p>I am indebted for these facts to Mr. J. N. Shoolbred, under +whose supervision the arrangements were made.</p> + +<p>Some excellent experience has been gained at the shipbuilding +docks in Barrow-in-Furness, where the Brush system has been applied +to illuminate several large sheds covering the punching and +shearing machinery, bending blocks, furnaces, and other branches of +this gigantic business. In one shed, which was formerly lighted by +large blast-lamps, in which torch oil was burnt, costing about 5d. +per gallon, and involving an expenditure of £8 9s. per week, +the electric light has been adopted at an expenditure of £4 +14s. per week.</p> + +<p>The erecting shop, 450 feet by 150 feet, formerly dimly lit by +gas at a cost of £22 per week, is now efficiently lit by +electricity at half the cost.</p> + +<p>I am indebted for these facts to Mr. Humphreys, the manager of +the works.</p> + +<p>The Post office authorities have contracted with Mr. M. E. +Crompton, to light up the Post-office at Glasgow for the same price +as they have hitherto paid for gas, and there is no doubt that in +many instances this arrangement will leave a handsome profit to the +Electric Light Company. They are about to try the Brockie system in +the telegraph galleries, and the Brush system in the newspaper +sorting rooms of the General Post-office in St. +Martin's-le-Grand.</p> + +<hr> +<p><a name="26"></a></p> + +<h2>ON THE SPACE PROTECTED BY A LIGHTNING-CONDUCTOR.</h2> + +<h3>By WILLIAM HENRY PREECE.</h3> + +<p>[Footnote: From the <i>Philosophical Magazine</i> for December, +1880.]</p> + +<p>Any portion of non-conducting space disturbed by electricity is +called an electric field. At every point of this field, if a small +electrified body were placed there, there would be a certain +resultant force experienced by it dependent upon the distribution +of electricity producing the field. When we know the strength and +direction of this resultant force, we know all the properties of +the field, and we can express them numerically or delineate them +graphically, Faraday (Exp. Res., § 3122 <i>et seq.</i>) showed +how the distribution of the forces in any electric field can be +graphically depicted by drawing lines (which he called <i>lines of +force</i>) whose direction at every point coincides with the +direction of the resultant force at that point; and Clerk-Maxwell +(Camb. Phil. Trans., 1857) showed how the magnitude of the forces +can be indicated by the way in which the lines of force are drawn. +The magnitude of the resultant force at any point of the field is a +function of the potential at that point; and this potential is +measured by the work done in producing the field. The potential at +any point is, in fact, measured by the work done in moving a unit +of electricity from the point to an infinite distance. Indeed the +resultant force at any point is directly proportional to the rate +of fall of potential per unit length along the line of force +passing through that point. If there be no fall of potential there +can be no resultant force; hence if we take any surface in the +field such that the potential is the same at every point of the +surface, we have what is called an <i>equipotential surface.</i> +The difference of potential between any two points is called an +electromotive force. The lines of force are necessarily +perpendicular to the surface. When the lines of force and the +equipotential surfaces are straight, parallel, and equidistant, we +have a <i>uniform field.</i> The intensity of the field is shown by +the number of lines passing through unit area, and the rate of +variation of potential by the number of equipotential surfaces +cutting unit length of each line of force. Hence the distances +separating the equipotential surfaces are a measure of the +electromotive force present. Thus an electric field can be mapped +or plotted out so that its properties can be indicated +graphically.</p> + +<p class="ctr"><img src="images/14a.png" alt="Fig. 1"></p> + +<p class="ctr">Fig. 1</p> + +<p>The air in an electric field is in a state of tension or strain; +and this strain increases along the lines of force with the +electromotive force producing it until a limit is reached, when a +rent or split occurs in the air along the line of least +resistance--which is disruptive discharge, or lightning.</p> + +<p class="ctr"><img src="images/14b.png" alt="Fig. 2"></p> + +<p class="ctr">Fig. 2</p> + +<p>Since the resistance which the air or any other dielectric +opposes to this breaking strain is thus limited, there must be a +certain rate of fall of potential per unit length which corresponds +to this resistance. It follows, therefore, that the number of +equipotential surfaces per unit length can represent this limit, or +rather the stress which leads to disruptive discharge. Hence we can +represent this limit by a length. We can produce disruptive +discharge either by approaching the electrified surfaces producing +the electric field near to each other, or by increasing the +quantity of electricity present upon them; for in each case we +should increase the electromotive force and close up, as it were, +the equipotential surfaces beyond the limit of resistance. Of +course this limit of resistance varies with every dielectric; but +we are now dealing only with air at ordinary pressures. It appears +from the experiments of Drs. Warren De La Rue and Hugo Muller that +the electromotive force determining disruptive discharge in air is +about 40,000 volts per centimeter, except for very thin layers of +air.</p> + +<p class="ctr"><img src="images/14c.png" alt="Fig. 3"></p> + +<p class="ctr">Fig. 3</p> + +<p>If we take into consideration a flat portion of the earth's +surface, A B (fig. 1), and assume a highly charged thunder-cloud, C +D, floating at some finite distance above it, they would, together +with the air, form an electrified system. There would be an +electric field; and if we take a small portion of this system, it +would be uniform. The lines, a b, a' b'...would be lines of force; +and cd, c' d', c" d' ...would be equipotential planes. If the cloud +gradually approached the earth's surface (Fig. 2), the field would +become more intense, the equipotential surfaces would gradually +close up, the tension of the air would increase until at last the +limit of resistance of the air, <i>e f</i>, would be reached; +disruptive discharge would take place, with its attendant thunder +and lightning. We can let the line, <i>e f</i>, represent the limit +of resistance of the air if the field be drawn to scale; and we can +thus trace the conditions that determine disruptive discharge.</p> + +<p class="ctr"><img src="images/14d.png" alt="Fig. 4"></p> + +<p class="ctr">Fig. 4</p> + +<p>If the earth-surface be not flat, but have a hill or a building, +as H or L, upon it, then the lines of force and the equipotential +planes will be distorted, as shown in Fig. 3. If the hill or +building be so high as to make the distance H h or L l equal to e f +(Fig. 2), then we shall again have disruptive discharge.</p> + +<p>If instead of a hill or building we erect a solid rod of metal, +G H, then the field will be distorted as shown in Fig. 4. Now, it +is quite evident that whatever be the relative distance of the +cloud and earth, or whatever be the motion of the cloud, there must +be a space, g g', along which the lines of force must be longer +than a' a or H H'; and hence there must be a circle described +around G as a center which is less subject to disruptive discharge +than the space outside the circle; and hence this area may be said +to be protected by the rod, G H. The same reasoning applies to each +equipotential plane; and as each circle diminishes in radius as we +ascend, it follows that the rod virtually protects a cone of space +whose height is the rod, and whose base is the circle described by +the radius, G a. It is important to find out what this radius +is.</p> + +<p class="ctr"><img src="images/14e.png" alt="Fig. 5"></p> + +<p class="ctr">Fig. 5</p> + +<p>Let us assume that a thunder-cloud is approaching the rod, A B +(Fig. 5), from above, and that it has reached a point, D', where +the distance. D' B, is equal to the perpendicular height, D' C'. It +is evident that, if the potential at D be increased until the +striking-distance be attained, the line of discharge will be along +D' C or D' B, and that the length, A C', is under protection. Now +the nearer the point D' is to D the shorter will be the length A C' +under protection; but the minimum length will be A C, since the +cloud would never descend lower than the perpendicular distance D +C.</p> + +<p>Supposing, however, that the cloud had actually descended to D +when the discharge took place. Then the latter would strike to the +nearest point; and any point within the circumference of the +portion of the circle, B C (whose radius is D B), would be at a +less distance from D than either the point B or the point C.</p> + +<p><i>Hence a lightning-rod protects a conic space whose height is +the length of the rod, whose base is a circle having its radius +equal to the height of the rod, and whose side is the quadrant of a +circle whose radius is equal to the height of the rod.</i></p> + +<p>I have carefully examined every record of accident that was +available, and I have not yet found one case where damage was +inflicted inside this cone when the building was properly +protected. There are many cases where the pinnacles of the same +turret of a church have been struck where one has had a rod +attached to it; but it is clear that the other pinnacles were +outside the cone; and therefore, for protection, each pinnacle +should have had its own rod. It is evident also that every +prominent point of a building should have its rod, and that the +higher the rod the greater is the space protected.</p> + +<hr> +<p><a name="27"></a></p> + +<h2>PHOTO-ELECTRICITY OF FLUOR-SPAR CRYSTALS.</h2> + +<p>Hantzel has communicated to the Saxon Royal Society of Science +some interesting observations on the production of electricity by +light in colored fluor-spar. The centers of the fluor-spar cubes +become negatively electric by the action of light. The electric +tension diminishes toward the edges and angles, and frequently +positive polarity is produced there. With very sensitive crystals a +short exposure to daylight is sufficient; by a long exposure to +light the electric current increases. The direct rays of the sun +act much more powerfully than diffused daylight, and the electric +carbon light is more powerful even than sunlight. The +photo-electric action of light belongs principally to the +"chemically active" rays; this is shown by the fact that the +production of electricity is extremely small behind a glass colored +with cuprous oxide, and behind a film of a solution of quinine +sulphate; while it is not appreciably diminished by a film of a +solution of alum. The photo-electric excitability of fluor-spar +crystals is increased by a moderate heat (80° to 100° +C.).</p> + +<hr> +<p><a name="28"></a></p> + +<h2>THE AURORA BOREALIS AND TELEGRAPH CABLES.</h2> + +<p>The January and February numbers of the <i>Elektrotechnische +Zeitschrift</i> contain a number of articles on this interesting +subject by several eminent electricians. Professor Foerster, +director of the observatory in Berlin, points out the great +importance of the careful study of earth currents, first observed +at Greenwich, and now being investigated by a committee appointed +by the German Government. He further points out, according to +Professor Wykander, of Lund, in Sweden, that a close connection +exists between earth currents, the protuberances of the sun, and +the aurora borealis, and that the nearly regular periodical +reappearance of protuberances in intervals of eleven years +coincides with similar periods of excessive magnetic earth currents +and the appearance of the aurora borealis. The remarkable +disturbing influences on telegraph wires and cables of the aurora +borealis observed from the 11th to 14th of August, 1880, have been +carefully recorded by Herr Geh. Postnath Ludwig in Berlin, and a +map of Europe compiled, showing the places affected, with the +extent to which telegraph wires and cables were influenced and +disturbed. Although the aurora was but faintly visible in England +and Germany, and in Russia only as far as 35° north, disturbing +influences were reported from all parts of Europe, the +Mediterranean, and Africa, and even Japan and the east coast of +Asia. As far south as Zanzibar, Mozambique, and Natal disturbances +were also noticed. They were in Europe most intense on the morning +of August 12, when they lasted the whole day, and increased again +in intensity toward eight o'clock in the evening, while they +suddenly ceased everywhere almost simultaneously. Scientific and +careful observations were only taken at a few places, but the +existence of earth currents in frequently changing direction and +varying intensity, was noticed everywhere. Long lines of wires were +more affected than short ones, and although some lines--for +instance the Berlin-Hamburg in an east-west direction--were not at +all influenced, no general law was noticed according to which +certain directions were freed from the disturbing influence. While, +for instance, the Red Sea cable was not noticeably affected, the +land line to Bombay, forming a continuation of this cable, was +materially disturbed. The Marseilles-Algiers cable, so seriously +influenced in 1871, showed no signs at all, but as may be expected, +the north of Europe suffered more than the south, and in Nystad, +Finland, the galvanometer indicated an intensity of current equal +to that of 200 Leclanché cells.</p> + +<p>Since thunderstorms are generally local, it is only natural that +their effect upon telegraph cables should also be confined to one +locality. Numerous careful observations, carried out over +considerable periods of time, show that the disturbing influences +of thunderstorms on telegraph lines are of less duration and more +varying in direction and intensity than those of the aurora +borealis. Long lines suffer less than short lines; telegraph wires +above ground are more easily and more intensely affected than +underground cables. It is, however, possible, that this is mainly +due to the fact that in the districts where strict records were +kept, in the German Empire, most of the long lines are underground +cables, while most of the short local lines are overground wires. +The results of the disturbances varied; in Hughes's apparatus the +armatures were thrown off, lines in operation indicated wrong +signs, dots became dashes, and the spaces were either multiplied in +size or number, according to the direction of the earth currents +induced by the thunderstorms. Since these observations extended +over nearly 2,000 cases, some conclusions might fairly be drawn +from them. For the purpose of a more complete knowledge on this +subject, Dr. Wykander recommends a series of regular observations +on earth currents to be carried out at different stations, well +distributed over the whole surface of the globe, these observations +to be made between six and eight A.M., and at the same time in the +evening. Special arrangements to be made at various stations to +record exceptionally intense disturbances during the phenomena of +the aurora borealis, notice to be taken of time, direction, +intensity, and all further particulars. Since this question appears +to bear a considerable amount of influence on underground cables, +it is one that deserves serious attention before earth cables are +more generally introduced; there can, however, be little doubt that +they are not nearly so much exposed as overhead wires to disturbing +influences of other kinds, such as snow, rain, wind, etc., while +they certainly do suffer, though perhaps in a less degree, by +electrical disturbances.--<i>Engineering</i>.</p> + +<hr> +<p><a name="29"></a></p> + +<h2>THE PHOTOGRAPHIC IMAGE: WHAT IT IS.</h2> + +<p>[Footnote: A communication to the Sheffield Photographic Society +in the <i>British Journal of Photography</i>.]</p> + +<p>It is quite possible that in the remarks I propose making this +evening in connection with the photographic art I may mention +topics and some details which are familiar to many present; but as +chemistry and optical and physical phenomena enter largely into the +theory and practice of photography, the field is so extensive there +is always something interesting and suggestive even in the +rudiments, especially to those who are commencing their studies. +Although this paper may be considered an introductory one, I do not +wish to load it with any historical account, or describe the early +methods of producing a light picture, but shall at once take for my +subject, "The Photographic Image: What It Is," and under this +heading I must restrict myself to the collodion and silver or wet +process, leaving gelatine dry plates, collodio-chloride, platinum, +carbontype, and the numerous other types which are springing up in +all directions for future consideration.</p> + +<p>Now, in an ordinary pencil, pen and ink, or sepia sketch we have +a deposit of a dark, non-reflecting substance, which gives the +outline of a figure on a lighter background. The different +gradations of shade are acquired by a more or less deposit of lead, +ink, or sepia. In photography--at least in the ordinary silver +process--the image is formed by a deposition of metallic silver or +organic oxide in a minute state of division, either on glass, +paper, or other suitable material. This is brought about by the +action of light and certain reagents. Light has long been +recognized as a motive power comparable with heat or electricity. +Its action upon the skin, fading of colors, and effect on the +growth of vegetable and animal organisms are well known; and, +although the exact molecular change in many instances is not +clearly understood, yet certain salts of silver, iron, the alkaline +bichromates, and some organic materials--as bitumen and +gelatine--have been pretty well worked out.</p> + +<p>It is a remarkable and well-known fact that the chloride, +iodide, and bromide of silver--called "sensitive salts" in +photography--are not susceptible (at least only slowly) to change +when exposed to the yellow, orange, and red rays. The longer wave +lengths of the spectrum, as you know, form, with violet, indigo, +blue, and green, white light. The diagram on the wall shows this +dispersion and separation of the primitive colors. These--the +yellow, orange, and red-- are called technically "non actinic" +rays, and the others in their order become more actinic until the +ultra violet is reached. The action of white light, or rays, +excluding yellow, orange, and red, has the effect of converting +silver chloride into a sub-chloride; it drives off one equivalent +of chlorine. Thus, silver chloride, +Ag<sub>2</sub>Cl<sub>2</sub>=Ag<sub>2</sub>Cl+Cl. When water is +present the water is decomposed. Hydrochloric acid, HCl, +hypochlorous acid, HClO is formed.</p> + +<p>The iodide of silver in like manner is changed into a +sub-iodide; but with water hydriodic acid is formed unless an +iodine absorbent be present--then into hypoiodic acid. The silver +bromide undergoes a similar change. When with light alone, a +sub-bromide, Ag<sub>2</sub>Br<sub>2</sub>=Ag<sub>2</sub>Br+Br, and +with water hypobromous acid. It is important to bear this in mind, +as one or other, and frequently both iodide and bromide of silver, +is the sensitive salt requisite or used in producing the invisible +image.</p> + +<p>The theory regarding these sensitive salts of silver is that, +being very unstable, <i>i. e.</i>, ready to undergo a molecular +change, the undulations produced in the ether, which pervades all +space, and the potential action or moving power of light is +sufficient to disturb their normal chemical composition; it +liberates some of the chlorine, iodine, or bromine, as the case may +be. This action, of course, applies to light from any source--the +sun, electricity, or the brighter hydrocarbons, also flame from gas +or candle, whether it comes direct as rays of white light or is +reflected from an object and conducted through a lens as a distinct +image upon the screen of a camera.</p> + +<p>I have no time to speak on the subject of lenses, only just to +mention that they are, or ought to be, achromatic, so as to +transmit white light and of perfect definition, and the amount of +light passed through should be as much as possible consistent with +a sharp image--at least when rapid exposure is attempted.</p> + +<p>I shall touch very lightly on the manipulative part of +photography, as that would be unnecessary; but a brief account of +the chemicals in use is essential to a right appreciation of the +theory of developing the image. In the first place, our object is +to get a film of some suitable material coated with a thin layer of +a sensitive salt of silver--say a bromo-iodide. By mixing certain +proportions of ammonium iodide and cadmium bromide, or an iodide +and bromide of cadmium with collodion--which is pyroxyline, a kind +of gun-cotton dissolved in ether and alcohol--a plate of glass is +coated, and before being perfectly dry is immersed in the nitrate +of silver bath. The silver nitrate solution, adhering and entering +to a slight extent the surface of the collodion, becomes converted +by an ordinary chemical action of affinity into silver iodide and +bromide.</p> + +<p>The ammonium and cadmium play a secondary part in the process, +and are not absolutely necessary in forming the image. The plate is +now extremely sensitive to light. When we have entered it into the +dark slide and camera, and then exposed to light, the change I +mentioned has taken place. The film is transformed into different +quantities of sub-iodide and sub-bromide of silver, according to +brilliancy of light. In addition, there is on the plate an amount +of unchanged silver nitrate which becomes useful in the second +stage, or development. The image is not seen as yet, being latent, +and requiring the well-known developing solution of sulphate of +iron, acetic acid, alcohol, and water. Practically we all recognize +the effect of a nicely-balanced wave of developer worked round a +plate. The high lights are first to appear as a darker color, till +the details of shadow come out; when this is reached the developer +is washed off. The chemical action is briefly thus, and it can be +shown by solutions without a photographic plate, as in a test tube: +Pour into this glass a solution of silver nitrate, AgNO, and add a +solution of ferrous sulphate, FeSO<sub>4</sub>. The ferrous +sulphate combines with the nitric acid, forming two new +salts--ferric nitrate and ferric sulphate. The silver is deposited. +Any other substance which will remove oxygen from silver nitrate +without combining with the silver would do the same, and metallic +silver would be thrown down. The formula, as shown on the diagram, +explains the interchange.</p> + +<p>When the developer is poured over the plate it attacks first the +free silver nitrate, and causes it to deposit extremely fine +particles of metallic silver. The question arises: How is it these +particles arrange themselves to form an image? This is explained by +the physical movement known as molecular attraction or affinity. +These particles are attracted first to the portions of the plate +where there is most sub-iodide and sub-bromide. In the shady parts +less silver is deposited. When the image is once started it follows +that particles of silver produced by the iron developer will cause +more to fall down on the face of those already present, and the +image is, of course, built up if the silver nitrate be all consumed +on the plate. The developer then becomes useless or injurious. The +presence of acetic acid checks the reduction of the silver, and the +alcohol facilitates the flow when the bath becomes charged with +ether and spirit.</p> + +<p>The molecular attraction just mentioned is made plainer by +reference to the simple lead tree experiment. We have here in this +bottle a piece of zinc rod introduced into a solution of acetate of +lead. A chemical change has taken place. The zinc has abstracted +the acetic acid and the lead is deposited on the zinc, and will +continue to be so until the solution is exhausted. The +irregularities of surface and arborescent appearance are well +shown. If the change were rapidly conducted the lead particles +would from their weight sink directly to the bottom instead of +aggregating together like ordinary crystals. I have constructed a +diagram of colored card, which will perhaps more clearly +demonstrate the relation of the different constituents. The lower +portion (Fig. a) represents a section of the glass plate or +support, the collodion film (Fig. b) having upon its surface a thin +layer of bromo-iodine silver (Fig. c), which, when exposed to a +well-lighted image, as in a camera, changes into different +gradations of sub-bromide and sub-iodide, as indicated by +irregular, dark masses in the film. The dotted marks immediately +above these are intended for the silver deposit (Fig. d)--clusters +of granules, more abundant in the well lighted and less in the +shaded parts of the picture, corresponding to the amount of +sub-bromide and iodide beneath.</p> + +<p class="ctr"><img src="images/15a.png" alt=""></p> + +<p class="ctr">SECTION OF SENSITIVE PLATE AFTER EXPOSURE AND DURING +DEVELOPMENT.<br> +<br> +d Silver deposit--Image, c Sub-bromide and sub-chloride<br> +(gradations of), b Collodion film--Substratum, a Section<br> +of glass plate--Support.</p> + +<p>The next point to consider is that of intensification--a process +seldom required in positive pictures, and would not be needed so +often in negatives if there was enough free silver nitrate on the +plate during development. The object, as we all know, in a +wet-plate negative is to get good printing density without +destruction of half-tone. It is a rule, I believe, in an +over-exposed picture to intensify after fixing the image, and in an +under-exposed picture to intensify before fixing. Whichever is done +the intention is similar, namely, to intercept in a greater degree +the light passing through a negative, so as to make a whiter and +cleaner print. The usual intensifier--and, I suppose, there is no +better--is pyrogallic acid, citric acid, water, and a few drops of +silver nitrate solution. Pyrogallic is the most active agent, and +might be used alone with water; but for special reasons it is not +desirable. As a chemical it has a great affinity for oxygen, and +will precipitate silver from a solution containing, for instance, +nitrate of silver. It also combines with the metal, forming a +pyrogallate--a dark brown, very non-actinic material. The use of a +few drops of AgNO<sub>3</sub> solution is very evident. A deposit +is added to the image already formed. Citric acid is the retarder +in this case. Alcohol is unnecessary, as the film is well washed +with water before the intensifier is used, consequently it flows +readily over the plate.</p> + +<p>As regards fixing, or, more properly, clearing the image: it is +the simple act of dissolving out or from the film all free nitrate, +chloride, iodide, or bromide. Cyanide of potassium does not attack +the metallic deposit unless very strong. It has then a tendency to +reduce the detail in the shadows.</p> + +<p>THOMAS H. MORTON, M.D.</p> + +<hr> +<p><a name="30"></a></p> + +<h2>GELATINE TRANSPARENCIES FOR THE LANTERN.</h2> + +<p>[Footnote: A communication to the Photographic Society of +Ireland.]</p> + +<p>Few of those who work with gelatine dry plates seem to be aware +of the great beauty of the transparencies for lantern or other uses +which can be made from them by ferrous oxalate development with the +greatest ease and certainty.</p> + +<p>I think this a very great pity, for I hold the opinion that the +lantern furnishes the most enjoyable and, in some cases, the most +perfect of all means of showing good photographic pictures. Many +prints from excellent negatives which may be passed over in an +album without provoking a remark will, if printed as transparencies +and thrown on the screen, call forth expressions of the warmest +admiration; and justly so, for no paper print can do that full +justice to a really good negative which a transparency does. This +difference is more conspicuous in these days of dry gelatine plates +and handy photographic apparatus, when many of our most interesting +negatives are taken on quarter or 5 x 4 plates the small size of +which frequently involves a crowding of detail, much of which will +be invisible in a paper print, but which, when unraveled or opened +out, as it were, by means of the lantern, enhances the beauty of +the pictures immensely.</p> + +<p>When I last had the pleasure of bringing this subject before the +members of our society, it may be remembered that I demonstrated +the ease and simplicity with which those beautiful results maybe +obtained, by printing in an ordinary printing frame by the light of +my petroleum developing lamp, raising one of its panes of ruby +glass for the purpose for five seconds, and then developing by +ferrous oxalate until I got the amount of intensity requisite. On +that evening, in the course of a very just criticism by one of our +members, Mr. J. V. Robinson, he pointed out what was undoubtedly a +defect, viz., a slightly opalescent veiling of the high lights, +which should range from absolutely bare glass in the highest +points. He showed that, in consequence of this veiling, the light +was sensibly diminished all over the picture. This veiling of the +high lights was a serious disadvantage in another important +particular, inasmuch as it lessened the contrast between the lights +and shadows of the picture, thereby robbing it of some of its charm +and deteriorating its quality.</p> + +<p>Since that evening I have endeavored, by a series of +experiments, to find out some means by which this opalescence might +be got rid of in the most convenient manner. Cementing the +transparency to a piece of plain, clear glass with Canada balsam, +as suggested by Mr. Woodworth, I found in practice to be open to +two formidable objections. One of these was that Canada balsam used +in this manner is a sticky, unpleasant substance to meddle with, +and takes a long time--nearly a month--to harden when confined +between plates in this manner. The other objection was of extreme +importance, namely, that, in consequence of commercial gelatine +plates not being prepared on perfectly flat glasses in all cases, I +found that, after squeezing out the superfluous balsam and the air +bubbles that might have formed from between the two plates, they +are liable to separate at the places where the transparency is not +flat, causing air bubbles to creep in from the edges, as you may +see from these examples. I, therefore, have discarded this method, +although it had the effect desired when successfully done.</p> + +<p>I have hit, however, upon another way of utilizing Canada +balsam, which, while retaining all the good qualities of the former +method, is not subject to any of its disadvantages. This consists +in diluting the balsam with an equal bulk of turpentine, and using +it as a varnish, pouring it on like collodion, flowing it toward +each corner, and pouring it off into the bottle from the last +corner, avoiding crapy lines by slowly tilting the plate, as in +varnishing. If the plate be warmed previously, the varnish flows +more freely and leaves a thinner coating of balsam behind on the +transparency. When the plate has ceased to drip, place it in a +plate drainer, with the corner you poured from lowest, and leave it +where dust cannot get at it for four or five days, when it will be +found sufficiently hard to be put into a plate box. The +transparency may be finished at any time afterward by putting a +clean glass of the same size along with it, placing one of the +blank paper masks sold for the purpose--either circular or +cushion-shaped to suit the subject--between the plates, and pasting +narrow strips of thin black paper over the edges to bind them +together. This method is very successful, as you may see from the +examples. It renders the high lights perfectly clear, and leaves a +film like glass over all the parts of the transparency where the +varnish has flowed.</p> + +<p>In order to avoid the risk of dust involved in this process, I +tried other means of arriving at similar results and with success, +for the plates I now submit to you have been simply rubbed or +polished, as I may say, with a mixture of one part of Canada balsam +to three parts of turpentine, using either a small tuft of French +wadding or a small piece of soft rag for the purpose, continuing +the rubbing until the plate is polished nearly dry. This method is +particularly successful, rendering the clear parts of the sky like +bare glass. I have here a plate which is heavily veiled--almost +fogged, in fact--one half of which I have treated in this way, +showing that the half so treated is beautifully clear, while the +other half is so veiled as to be apparently useless.</p> + +<p>I have tried to still further simplify this necessary clearing +of those plates, and find that soaking tor twelve hours in a +saturated solution of alum, after washing the hypo out of the +plate, is successful in a large number of cases; and where it is +successful there is no further trouble with the transparency, +except to mount it after it becomes dry. Where it is not entirely +successful I put the plate into a solution of citric acid, four +ounces to a pint of water, for about one minute, and have in nearly +all cases succeeded in getting a beautifully-clear plate. The +picture must not be left long in the citric acid solution, or it +will float off; neither do I like using citric acid until after +trying the alum, for a similar reason.</p> + +<p>I may mention that I recommend a short exposure in the +printing-frame and slow development, in order to get sufficient +intensity. Of course the exposure is always made to a gas or +petroleum light. I also still prefer the old method of making the +ferrous oxalate solution, pouring it back into the bottle each time +after using, and using it for two or three months, keeping the +bottle full from a stock bottle, and occasionally putting a little +dry ferrous oxalate into the bottle and shaking it up, allowing it +to settle before using next time. By treating it in this way it +retains its power fairly well for a long time; and as it becomes +less active I give a little longer exposure, balancing one against +the other. Making the ferrous oxalate solution from two saturated +solutions of iron sulphate and potassium oxalate has not succeeded +so well with me for transparencies. The tone of the picture is not +so black as when developed by the old method; and I do not like +gray transparencies for the lantern. I also recommend very slow +gelatine plates, about twice as sensitive as wet collodion--not +more, if I can help it.</p> + +<p>I have demonstrated, I hope to your satisfaction, the +possibility of producing lantern slides from commercial gelatine +plates of a most beautiful quality--ranging from clear glass to +deep black, and giving charming gradation of tones, showing on the +screen a film as structureless as albumen slides, without the great +trouble involved in making them. You must not accept the slides put +before you this evening as the best that can be done with gelatine. +Far from it; they are only the work of an amateur with very little +leisure now to devote to their manufacture, and are merely the +result of a series of experiments which, so far as they have gone, +I now place before you.--<i>Thomas Mayne, T. C., in British Journal +of Photography.</i></p> + +<hr> +<p><a name="31"></a></p> + +<h2>AN INTEGRATING MACHINE.</h2> + +<p>[Footnote: Read at a meeting of the Physical Society, Feb. +26.]</p> + +<p>By C.V. BOYS.</p> + +<p>All the integrating machines hitherto made, of which I can find +any record, may be classed under two heads, one of which, Ainslee's +machine, is the sole representative, depending on the revolution of +a disk which partly rolls and partly slides on the paper, and the +other comprising all the remaining machines depending on the +varying diameters of the parts of a rolling system. Now, none of +these machines do their work by the method of the mathematician, +but in their own way. My machine, however, is an exact mechanical +translation of the mathematical method of integrating y dx, and +thus forms a third type of instrument.</p> + +<p>The mathematical rule may be described in words as follows: +Required the area between a curve, the axis of x and two ordinates; +it is necessary to draw a new curve, such that its steepness, as +measured by the tangent of the inclination, may be proportional to +the ordinate of the given curve for the same value of x, then the +<i>ascent</i> made by the new curve in passing from one ordinate to +the other is a measure of the area required.</p> + +<p>The figure shows a plan and side elevation of a model of the +instrument, made merely to test the idea, and the arrangement of +the details is not altogether convenient. The frame-work is a kind +of T square, carrying a fixed center, B, which moves along the axis +of x of the given curve, a rod passing always through B carries a +pointer, A, which is constrained to move in the vertical line, ee, +of the T square, A then may be made to follow any given curve. The +distance of B from the edge, ee, is constant; call it K, therefore, +the inclination of the rod, AB, is such that its tangent is equal +to the ordinate of the given curve divided by K; that is, the +tangent of the inclination is proportional to the ordinate; +therefore, as the instrument is moved over the paper, AB has always +the inclination of the desired curve.</p> + +<p>The part of the instrument that draws the curve is a +three-wheeled cart of lead, whose front wheel, F, is mounted, not +as a caster, but like the steering wheel of a bicycle. When such a +cart is moved, the front wheel, F, can only move in the direction +of its own plane, whatever be the position of the cart; if, +therefore, the cart is so moved that F is in the line, ee, and at +the same time has its plane parallel to the rod, AB, then F must +necessarily describe the required curve, and if it is made to pass +over a sheet of black tracing paper, the required curve will be +<i>drawn</i>. The upper end of the T square is raised above the +paper, and forms a bridge, under which the cart travels. There is a +longitudinal slot in this bridge in which lies a horizontal wheel, +carried by that part of the cart corresponding to the head of a +bicycle. By this means the horizontal motion communicated to the +front wheel of the cart by the bridge, is equal to that of the +pointer, A; at the same time the cart is free to move +vertically.</p> + +<p>The mechanism employed to keep the plane of the front wheel of +the cart parallel to AB is made clear by the figure. Three equal +wheels at the ends of two jointed arms are connected by an open +band, as shown. Now, in an arrangement of this kind, however the +arms or the wheels are turned, lines on the wheels, if ever +parallel, will always be so. If, therefore, the wheel at one end is +so supported that its rotation is equal to that of AB, while the +wheel at the other end is carried by the fork which supports F, +then the plane of F, if ever parallel to AB, will always be so. +Therefore, when A is made to trace any given curve, F will draw a +curve whose ascent is (1/K) f y dx, and this, multiplied by K, is +the area required.</p> + +<p class="ctr"><a href="images/16a.png"><img src= +"images/16a_th.png" alt="AN INTEGRATING MACHINE."></a></p> + +<p class="ctr">AN INTEGRATING MACHINE.</p> + +<p>Not only does the machine integrate y dx, but if the plane of +the front wheel of the cart is set at right angles instead of +parallel to AB, then the cart finds the integral of dx / y, and +thus solves problems, such, for instance, as the time occupied by a +body in moving along a path when the law of the velocity is +known.</p> + +<p>Some modifications of the machine already described will enable +it to integrate squares, cubes, or products of functions, or the +reciprocals of any of these.</p> + +<p>Of the various curves exhibited which have been drawn by the +machine, the following are of special physical interest.</p> + +<p>Given the inclined straight line y = cx, the machine draws the +parabola y = cx² / 2. This is the path of a projectile, as the +space fallen is as the area of the triangle between the inclined +line, the axis of x, and the traveling ordinate.</p> + +<p>Given the curve representing attraction y = 1 / x² the +machine draws the hyperbola y = 1 / x the curve representing +potential, as the work done in bringing a unit from an infinite +distance to a point is measured by the area between the curve of +attraction, the axis of x, and the ordinate at that point.</p> + +<p>Given the logarithmic curve y = e<sup>x</sup>, the machine draws +an identical curve. The vertical distance between these two curves, +therefore, is constant; if, then, the head of the cart and the +pointer, A, are connected by a link, this is the only curve they +can draw. This motion is very interesting, for the cart pulls the +pointer and the pointer directs the cart, and between they +calculate a table of Naperian logarithms.</p> + +<p>Given a wave-line, the machine draws another wave-line a quarter +of a wave-length behind the first in point of time. If the first +line represents the varying strengths of an induced electrical +current, the second shows the nature of the primary that would +produce such a current.</p> + +<p>Given any closed curve, the machine will find its area. It thus +answers the same purpose as Ainslee's polar planimeter, and though +not so handy, is free from the defect due to the sliding of the +integrating wheel on the paper.</p> + +<p>The rules connected with maxima and minima and points of +inflexion are illustrated by the machine, for the cart cannot be +made to describe a maximum or a minimum unless the pointer, A, +<i>crosses</i> the axis of x, or a point of inflexion unless A +passes a maximum or minimum.</p> + +<hr> +<p><a name="32"></a></p> + +<h2>UPON A MODIFICATION OF WHEATSTONE'S MICROPHONE AND ITS +APPLICABILITY TO RADIOPHONIC RESEARCHES.</h2> + +<p>[Footnote: A paper read before the Philosophical Society of +Washington. D. C., June 11, 1881.]</p> + +<h3>By ALEXANDER GRAHAM BELL.</h3> + +<p>In August, 1880, I directed attention to the fact that thin +disks or diaphragms of various materials become sonorous when +exposed to the action of an intermittent beam of sunlight, and I +stated my belief that the sounds were due to molecular disturbances +produced in the substance composing the diaphragm.[1] Shortly +afterwards Lord Raleigh undertook a mathematical investigation of +the subject and came to the conclusion that the audible effects +were caused by the bending of the plates under unequal heating.[2] +This explanation has recently been called in question by Mr. +Preece,[3] who has expressed the opinion that although vibrations +may be produced in the disks by the action of the intermittent +beam, such vibrations are not the cause of the sonorous effects +observed. According to him the aerial disturbances that produce the +sound arise spontaneously in the air itself by sudden expansion due +to heat communicated from the diaphragm--every increase of heat +giving rise to a fresh pulse of air. Mr. Preece was led to discard +the theoretical explanation of Lord Raleigh on account of the +failure of experiments undertaken to test the theory.</p> + +<p>[Footnote 1: Amer. Asso. for Advancement of Science, August 27, +1880.]</p> + +<p>[Footnote 2: <i>Nature</i>, vol. xxiii., p. 274.]</p> + +<p>[Footnote 3: Roy. Soc., Mar. 10, 1881.]</p> + +<p class="ctr"><img src="images/16b.png" alt= +"Fig. 1. A B, Carbon Supports. C, Diaphragm."></p> + +<p class="ctr">Fig. 1. A B, Carbon Supports. C, Diaphragm.</p> + +<p>He was thus forced, by the supposed insufficiency of the +explanation, to seek in some other direction the cause of the +phenomenon observed, and as a consequence he adopted the ingenious +hypothesis alluded to above. But the experiments which had proved +unsuccessful in the hands of Mr. Preece were perfectly successful +when repeated in America under better conditions of experiment, and +the supposed necessity for another hypothesis at once vanished. I +have shown in a recent paper read before the National Academy of +Science,[1] that audible sounds result from the expansion and +contraction of the material exposed to the beam, and that a real +to-and-fro vibration of the diaphragm occurs capable of producing +sonorous effects. It has occurred to me that Mr. Preece's failure +to detect, with a delicate microphone, the sonorous vibrations that +were so easily observed in our experiments, might be explained upon +the supposition that he had employed the ordinary form of Hughes's +microphone shown in Fig. 1, and that the vibrating area was +confined to the central portion of the disk. Under such +circumstances it might easily happen that both the supports (a b) +of the microphone might touch portions of the diaphragm which were +practically at rest. It would of course be interesting to ascertain +whether any such localization of the vibration as that supposed +really occurred, and I have great pleasure in showing to you +tonight the apparatus by means of which this point has been +investigated (see Fig. 2).</p> + +<p>[Footnote 1: April 21, 1881.]</p> + +<p class="ctr"><img src="images/16c.png" alt=""></p> + +<p class="ctr">Fig. 2. A, Stiff wire. B, Diaphragm. C, Hearing +tube.<br> +D, Perforated handle.</p> + +<p>The instrument is a modification of the form of microphone +devised in 1872 by the late Sir Charles Wheatstone, and it consists +essentially of a stiff wire, A, one end of which is rigidly +attached to the center of a metallic diaphragm, B. In Wheatstone's +original arrangement the diaphragm was placed directly against the +ear, and the free extremity of the wire was rested against some +sounding body--like a watch. In the present arrangement the +diaphragm is clamped at the circumference like a telephone +diaphragm, and the sounds are conveyed to the ear through a rubber +hearing tube, c. The wire passes through the perforated handle, D, +and is exposed only at the extremity. When the point, A, was rested +against the center of a diaphragm upon which was focused an +intermittent beam of sunlight, a clear musical tone was perceived +by applying the ear to the hearing tube, c. The surface of the +diaphragm was then explored with the point of the microphone, and +sounds were obtained in all parts of the illuminated area and in +the corresponding area on the other side of the diaphragm. Outside +of this area on both sides of the diaphragm the sounds became +weaker and weaker, until, at a certain distance from the center, +they could no longer be perceived.</p> + +<p>At the point where we would naturally place the supports of a +Hughes microphone (see Fig. 1) no sound was observed. We were also +unable to detect any audible effects when thepoint of the +microphone was rested against the support to which the diaphragm +was attached. The negative results obtained in Europe by Mr. Preece +may, therefore, be reconciled with the positive results obtained in +America by Mr. Tainter and myself. A still more curious +demonstration of localization of vibration occurred in the case of +a large metallic mass. An intermittent beam of sunlight was focused +upon a brass weight (1 kilogramme), and the surface of the weight +was then explored with the microphone shown in Fig. 2. A feeble but +distinct sound was heard upon touching the surface within the +illuminated area and for a short distance outside, but not in other +parts.</p> + +<p>In this experiment, as in the case of the thin diaphragm, +absolute contact between the point of the microphone and the +surface explored was necessary in order to obtain audible effects. +Now I do not mean to deny that sound waves may be originated in the +manner suggested by Mr. Preece, but I think that our experiments +have demonstrated that the kind of action described by Lord Raleigh +actually occurs, and that it is sufficient to account for the +audible effects observed.</p> + +<hr> +<p>A catalogue, containing brief notices of many important +scientific papers heretofore published in the SUPPLEMENT, may be +had gratis at this office.</p> + +<hr> +<h2>THE SCIENTIFIC AMERICAN SUPPLEMENT.</h2> + +<h3>PUBLISHED WEEKLY.</h3> + +<p><b>Terms of Subscription, $5 a Year.</b></p> + +<p>Sent by mail, postage prepaid, to subscribers in any part of the +United States or Canada. 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Patents are obtained on the best terms.</p> + +<p>A special notice is made in the <b>Scientific American</b> of +all Inventions patented through this Agency, with the name and +residence of the Patentee. By the immense circulation thus given, +public attention is directed to the merits of the new patent, and +sales or introduction often easily effected.</p> + +<p>Any person who has made a new discovery or invention can +ascertain, free of charge, whether a patent can probably be +obtained, by writing to MUNN & Co.</p> + +<p>We also send free our Hand Book about the Patent Laws, Patents, +Caveats. Trade Marks, their costs, and how procured, with hints for +procuring advances on inventions. Address</p> + +<p><b>MUNN & CO., 37 Park Row, New York.</b></p> + +<p>Branch Office, cor. F and 7th Sts., Washington, D. 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