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diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..6833f05 --- /dev/null +++ b/.gitattributes @@ -0,0 +1,3 @@ +* text=auto +*.txt text +*.md text diff --git a/8391-8.txt b/8391-8.txt new file mode 100644 index 0000000..6abc8ba --- /dev/null +++ b/8391-8.txt @@ -0,0 +1,5182 @@ +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. + + + + + + + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 288 + + + + +NEW YORK, JULY 9, 1881 + +Scientific American Supplement. Vol. XI, No. 288. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + + TABLE OF CONTENTS. + +I. ENGINEERING AND MECHANICS--Dry Air Refrigerating Machine. + 5 figures. Plan, elevation, and diagrams of a new English + dry air refrigerator + + Thomas' Improved Steam Wheel. 1 figure + + 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 + +II. 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. + + Detection of Alcohol in Transparent Soaps. By H. JAY + + On the Calorific Power of Fuel, and on Thompson's Calorimeter. + By J.W. THOMAS + + Explosion as an Unknown Fire Hazard. A suggestive review of + the conditions of explosions, with curious examples + + Carbon. Symbol C. Combining weight. 12. By T. A. POOLEY + Second article on elementary chemistry written for brewers + + Manufacture of Soaps and their Production. By W. J. MENZIES + + The Preparation of Perfume Pomades. 1 figure. "Ensoufflage" + apparatus for perfumes + + Organic Matter in Sea Water + + Bacteria Life. Influence of heat and various gases and chemical + compounds on bacteria life + + On the Composition of Elephant's Milk. By Dr. CHAS. A. DOREMUS. + Comparison of elephant's milk with that of ten other mammals + + The Chemical Composition of Rice. Maize, and Barley. By J. STEINER + + Petroleum Oils. Character and properties of the various distillates + of crude petroleum. Fire risks attending the use of the + lighter petroleum oils + + Composition of the Petroleum of the Caucasus. By P. SCHULZENBERGER + and N. TONINE + + Notes on Cananga Oil. or Ilang-Ilang Oil. By F. A. FLÜCKIGER. + 1 figure. Flower and leaf of Cananga odorata + + Chian Turpentine, and the Tree which Produces It. By Dr. + STIEPOWICH. of Chios, Turkey + + On the Change of Volume which Accompanies the Galvanic Deposition + of a Metal. By M. E. BOUTY + + Analysis of the Rice Soils of Burmah. By R. ROMANIC, Chemical + Examiner, British Burmah + +III. 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 + + 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 + + The Future Development of Electrical Appliances. Lecture by + Prof. J. W. PERRY before the London Society of Arts.--Methods + and units of electrical measurements + + Researches on the Radiant Matter of Crookes and the Mechanical + Theory of Electricity. By Dr. W. F. GINTL + + Economy of the Electric Light. W. H. PREECE'S Experiments + Investigations + + On the Space Protected by a Lightning Conductor. By WM. H. + PREECE.--5 figures + + Photo-Electricity of Fluor Spar Crystals + + The Aurora Borealis and Telegraph Cables + + The Photographic Image: What It Is. By T. H. MORTON. + 1 figure.--Section of sensitive plate after exposure and during + development + + Gelatine Transparencies for the Lantern + + An Integrating Machine. By C. V. BOYS.--1 figure + + Upon a Modification of Wheatstone's Microphone and its + Applicability to Radiophonic Researches. + By ALEX. GRAHAM BELL,--2 figures + +IV. ARCHITECTURE.--Suggestions in Architecture, 1 figure.--A + pair of English cottages. By A. CAWSTON + + * * * * * + + + + +ALCOHOL IN NATURE--ITS PRESENCE IN THE EARTH, WATER, AND ATMOSPHERE. + + +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. + +[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.] + +[Illustration: FIG. 1.--FIRST DISTILLATORY APPARATUS.] + +[Illustration: FIG. 2.--SECOND DISTILLATORY APPARATUS.] + +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. + +[Illustration: Fig. 3.--IODOFORM CRYSTALS OBTAINED DIRECTLY (greatly +magnified).] + +[Illustration: FIG. 4,--IODOFORM CRYSTALS OBTAINED WITH RAIN WATER.] + +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. + +[Illustration: FIG. 5.--IODOFORM CRYSTALS OBTAINED WITH SNOW WATER.] + +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.--_La Nature_. + +[Illustration: FIG. 6.--IODOFORM CRYSTALS OBTAINED WITH VEGETABLE +MOULD.] + + * * * * * + + + + +DETECTION OF ALCOHOL IN TRANSPARENT SOAPS. + +By H. JAY. + + +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. + + * * * * * + + + + +ON THE CALORIFIC POWER OF FUEL, AND ON THOMPSON'S CALORIMETER. + +By J.W. THOMAS, F.C.S., F.I.C. + + +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. + +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: + +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. + +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. + +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): + + Composition per cent. + +Carbon...............................88.33 +Hydrogen............................. 5.08 +Oxygen............................... 3.28 +Nitrogen............................. 0.55 +Sulphur.............................. 0.70 +Ash.................................. 1.26 +Water (moisture)..................... 0.80 + ----- + 100.00 + +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. + +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 _total heat units_ 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 _heat unit_ 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 _all_ 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. + +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 _not_ 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: + + Room at The water should be + + 80° F. 70° F. + 72 64 + 67 60 + 60 54 + 55 50 + 50 46 + 42 40 + +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. + +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. + +By paying attention to such details, and following the method +recommended, the apparatus yields very satisfactory results with +bituminous and semi-bituminous coals.--_Chemical News_. + + * * * * * + + + + +EXPLOSION AS AN UNKNOWN FIRE HAZARD. + + +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 _noise_; it grew to comprehend the idea of _force_ +accompanied with violent outburst; it is advancing to a stage in which +it implies _combustion_ 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. + +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 _fire_ 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 _vs_. 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 _proximate_ cause; and if fire cause +explosion, and explosion cause loss, it is a loss by fire as _efficient_ +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." + +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. + +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. + +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. + +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 _rapid_ 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. + +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, _freely open to the air_. If ignited by a flame, however, in +an unconfined place, gun-cotton only burns with a strong blaze, but +if _confined_ where the temperature reaches 340° F., it explodes with +terrific violence. Somewhat similar is the action of nitro-glycerine and +dynamite, which simply _burn_ if ignited in the open air, while the same +substance will _explode_ 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 _so long as the nail will continue +to enter the wood_. + +[Footnote 1: The purest gun-cotton may be regarded as a _cellulose_, +in which three atoms of hydrogen are replaced by three molecules of +peroxide of nitrogen.] + +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. + +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. + +"The germ of the first knowledge of an explosive was probably the +accidental discovery, ages ago, of the deflagrating property of the +natural saltpeter _when in contact with incandescent charcoal_."[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] + +[Footnote 1: Encyclopædia Britannica, new edition, viii, p. 806.] + +[Footnote 2: _Vide_ Abel's Experiments in Gunpowder, as detailed in +Phil. Trans. Eoy. Soc, 1874.--_Vide_ also _Bull. Soc. d'Encouragement_, +Nov., 1880, p. 633, _Sur les Explosives_.] + +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_3) for the carbon of the charcoal, and the +production of carbonic acid gas (CO_2) 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_2 is reached. Considering +that water (H_2O) 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. + +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 _at_ 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 _warm or hot water_, 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 +_sea water_ was poured on them. + +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. + +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. + +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. + +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 +_employee_ 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. + +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. + +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 _hoisted_ up +and then squashed down." _Query:_ 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.--_American Exchange and +Review._ + + * * * * * + + + + +CARBON.--SYMBOL C.--COMBINING WEIGHT 12. + +By T.A. POOLEY, B.Sc., F.C.S. + + +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 _allotropism_, +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. + +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. + +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. + +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. + +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. + +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. + +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. + +_Carbon Dioxide, or Carbonic Acid, Symbol CO_2_.--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. + +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: + + CaCO_3 + 2HCl = CO_2 + H_2O + CaCl_2 + Calcium Hydrochloric Carbonic Water. Calcium +Carbonate. Acid. Acid. Chloride. + +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. + +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. + +_Carbon Monoxide, or Carbonic Oxide. Symbol CO._--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.--_Brewers' +Guardian._ + + * * * * * + + + + +SEYFFERTH'S PYROMETER. + + +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. + +[Illustration: Fig. 1.--Pyrometer with Electric Indicator.] + +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. + +[Illustration: Fig. 2.--Method of Mounting by means of a cone on vacuum +apparatus.] + +[Illustration: Fig. 3.--Mounting by means of a sleeve on vacuum +apparatus.] + +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. + +_Pyrometers filled with Ether._-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. + +_Pyrometers filled with distilled water_ are used for ascertaining +temperatures ranging from 100° to 265° C., 80° to 210° R., or 212° to +510° F. + +_Pyrometers filled with mercury_ are constructed for ascertaining +temperatures from 360° to 750° C. + +[Illustration: Fig. 4.--Mounting on horizontal pipes by thread on the +tube.] + +[Illustration: Fig. 5.--Mounting by means of a clasp in reservoirs.] + + +APPLICATION OF THE PYROMETER IN BONE BLACK FURNACES. + +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. + +The position that the pyrometer should occupy is subordinate to the +construction of the furnace. Fig. 6 shows the type which is most +employed. + +[Illustration: Fig. 6.--The Pyrometer mounted on a bone-black furnace.] + +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. + +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. + + +APPLICATION OF THE APPARATUS TO BRICK FURNACES AND IN THE MANUFACTURE OF +CHEMICAL PRODUCTS. + +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. + +[Illustration: Fig. 7.--The Pyrometer mounted on a brick furnace.] + + * * * * * + + + + +MANUFACTURERS' SOAPS AND THEIR PRODUCTION. + +By W. J. MENZIES. + + +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. + +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. + +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. + +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 +_alkaline_ 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. + +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. + +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. + +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. + +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.--_Textile Manufacturer._ + + * * * * * + + + + +THE PREPARATION OF PERFUME POMADES. + + +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] + +[Footnote 1: Our illustration has been taken from C. Hofmann, +"Chemisch-technisches Universal-Receptbuch," 8vo, Berlin, 1879, p. 207.] + +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.--_New Remedies._ + +[Illustration: "ENSOUFFLAGE" APPARATUS FOR PERFUMES.] + + * * * * * + + + + +ORGANIC MATTER IN SEA-WATER. + + +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 (_Chem. Soc. Journ_., 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. + + * * * * * + + + + +BACTERIA LIFE. + + +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. + +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. + + * * * * * + + + + +ON THE COMPOSITION OF ELEPHANTS' MILK. + +[Footnote: Read before the American Chemical Society, June 3,1881.] + +By CHAS. A. DOREMUS, M.D., Ph.D. + + +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. + +Through the courtesy of Jas. A. Bailey I was enabled to procure samples +of the milk on several occasions. + +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. + +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. + +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. + +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. + +The following represents approximately the daily diet of the mother: + +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. + +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. + +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. + +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. + +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. + +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: + + + No. I. II. III. + April 5, April 9, April 10, + Morning. Noon. Morning. + + Quantity, 19 cc. 36 cc. 72 cc. + Cream, 52-4, vol.% 58 62 + Reaction, Neutral. Slightly alkaline. Slightly acid. + Sp.gr., ---- ---- 1023.7 + + 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 + + +Ten grammes were taken for analysis, and in No. III. duplicates were +made. + +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. + +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. + +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. + +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. + +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. + +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. + +[Footnote 1: "Lehrhuch der Physiologischen Chemie," pp. 423 and 424.] + +Constituents. Woman. Cow. Goat. Ewe. Ass. Mare. + +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 + +Constituents. Buffalo. Camel. Sow. Hippo- Elephant. + potamus. + +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 + +[Footnote 1: Milk Sugar included.] + +It may be remarked that though approaching the composition of cream it +still differs enough to require it to be considered milk. + +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. + +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. + +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. + +In size the "Baby" compared equally with other elephants in the same +menagerie, who were known to be four and five years old. + +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. + + * * * * * + + + + +THE CHEMICAL COMPOSITION OF RICE, MAIZE, AND BARLEY. + +By J. STEINER, F.C.S. + + +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. + +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: + + Barley. Maize. Rice. + -------------- ------------- ------------------ + Air Dried at Air Dried at Air Dried at With + Dry. 100° C. Dry. 100° C. Dry. 100° C. Husk. + +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 + +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. + +But on the other hand, barley and maize are richer in albuminous matter +and in ash. The extractive matter, _i. e._, 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). + +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. + + 100 parts of + Potash Lime Magnesia Phosphoric Silica grain contain + acid ash. + +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 " + +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. + +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.--_London +Brewers' Journal._ + + * * * * * + + + + +PETROLEUM OILS. + + +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. + +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. + +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. + +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 _per se_, 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. + +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.--_Fireman's Journal_ + + * * * * * + + + + +COMPOSITION OF THE PETROLEUM OF THE CAUCASUS. + +By MM. P SCHUTZENBERGER and N. TONINE. + + +All portions of this petroleum contain saturated carbides of the formula +C_nH_{2n}, which the authors name paraffenes. At a bright red heat they +yield benzinic carbides, C_nH_{2n-6}, 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. + + * * * * * + + + + +NOTES ON CANANGA OIL OR ILANG-ILANG OIL. + +[Footnote: From the _Archiv der Pharmacie_.] + +By F. A. FLÜCKIGER. + + +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. + +The tree, of which the flowers yield the oil known under the name +"Ilang-ilang" or "Alanguilan," is the _Cananga odorata_, 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, _Uvaria odorata_." According to Roxburgh,[6] +the plant was in 1797 brought from Sumatra to the Botanical Gardens in +Calcutta. Dunal devoted to the _Ucaria odorata_, or, properly, _Unona +odorata_, 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. + +[Footnote 1: "Flora Indica," i (1855), 130.] + +[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, _New Remedies_, April, 1881, page 98.] + +[Footnote 3: Ray. "Historia Plantarum, Supplementum," tomi i et ii +"Hist. Stirpium Insulæ Luzonensis et Philippinarum" a Georgio Josepho +Canello; London, 1704, 83] + +[Footnote 4: "Herbarium Amboinense, Amboinsch Kruidboek," ii. +(Amsterdam, 1750), cap. xix, fol. 195 and tab. 65.] + +[Footnote 5: "Encyclopédie méthodique. Botanique," i (1783), 595.] + +[Footnote 6: "Flora Indica," ii. (Serampore, 1832), 661.] + +[Footnote 7: Paris, 1817, p. 108, 105.] + +Lastly, we owe a very handsome figure of the _Cananga odorata_ 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 _Unona odoratissima_, 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 _Uvaria_, from which he would not +separate the Ilang-ilang tree. + +[Footnote 1: Vol. i. (Brussels, 1829), fol. 29, tab ix et xiv. B.] + +[Footnote 2: "Flora de Filipinas," Manila, 1845, 325. _Unona +odoratissima_, 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.] + +[Footnote 3: "Dictionnaire de Botanique."] + +[Illustration: CANAGA ODORATA] + +The notice of Maximowicz,[1] "Ueber den Ursprung des Parfums +Ylang-Ylang," contains only a confirmation of the derivation of the +perfume from Cananga. + +[Footnote 1: Just's "Botanischer Jahresbericht," 1875, 973.] + +_Cananga odorata_ 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 _Cananga odorata_ 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. + +_Cananga odorata_, 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 _Unona_ or _Uvaria_, among +which some equally possess odorous flowers, are now distributed between +those two genera, which are tolerably rich in species. From _Uvaria_ +the _Cananga_ differs in its valvate petals, and from _Unona_ in the +arrangement of the seeds in two rows. + +[Footnote 1: "Genera Plantarum," i, (1864), 24.] + +_Cananga odorata_ 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 _Michelia champaca_, 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" (_Michelia champaca_) and the "Kenangga wangi" +(_Cananga odorata_)[2] stand in the first rank. + +[Footnote 1: A beautiful figure of this also is given in Blume's "Flora +Javæ," iii., Magnoliaceæ, tab. I.] + +[Footnote 2: Junghuhn, Java, Leipsic, 1852, 166.] + +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] + +[Footnote 1: _Jahresbericht d. Pharmacie_, by Wiggers and Husemann, +1867, 422.] + +[Footnote 2: _Jahresbericht_, 1868, 166.] + +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 _Michelia champaca_, 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. + +[Footnote 1: _Archiv der Pharmacie_, ccxiv. (1879), 18.] + +[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).] + +[Footnote 3: 25 grammes of oil from 5 kilogrammes of flowers, according +to Reymann.] + +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 _Cananga odorata_ and _Michelia champaca_, and colored +yellow by means of turmeric. In India unguents of this kind have always +been in use. + +[Footnote 1: _Histoire Naturelle des Drogues Simples_, iii. (1850), +675.] + +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 _Cananga odorata_, +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 _Andropogon +laniger_. + +[Footnote 1: Compare Flückiger, "Pharmakognosic," 2d edit, 1881, p. +152.] + +[Footnote 2: Flückiger, "Documente zur Geschichte der Pharmacie," Halle +(1876), p 93.] + +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. + +[Footnote 1: _Comptes Rendus_, lxxvi. (1873), 1428, and abstracted in +the _Pharmaceutical Journal_ [3], iv., p. 28; also in _Jahresbericht_, +1873, p. 431.] + +[Footnote 2: Overlooking Peru balsam and Tolu balsam.] + +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. + + * * * * * + + + + +CHIAN TURPENTINE. + + +The following letter has been received by the editors of the _Repertoire +de Pharmacie:_ 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. + +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. + +The turpentine tree (_Pistacia terebinthus_ 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. + +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. + +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. + +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 +(_Pistacia lentiscus_ 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. + +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. + +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., + +DR. STIEPOWICH. + +Chio, Turkey. + + * * * * * + + + + +ON THE CHANGE OF VOLUME WHICH ACCOMPANIES THE GALVANIC DEPOSITION OF A +METAL. + +By M. E. BOUTY. + + +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 _neutral point of temperatures_. + +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 _neutral point +of compression_ 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. + +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: + + A t + (1) y = ------- + B + t + +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: + + (2) A = - a'i + b'i², + +of the same form as the expression E: + + E = - ai + bi², + +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. + +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.--_Comptes Rendus._ + + * * * * * + + + + +ANALYSES OF RICE SOILS FROM BURMAH. + +By R. ROMANIS, D.Sc., Chemical Examiner, British Burmah. + + +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. + +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. + +Results of two analyses of soils from Syriam, near Rangoon, are +appended: + + _Soluble in Hydrochloric Acid_. + + 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 + + _Soluble in Sulphuric Acid_. + +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 + + _Residue_. + +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 + +These are alluvial soils from the Delta of the Irrawaddy. + + * * * * * + + + + +DRY AIR REFRIGERATING MACHINE. + + +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! + +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. + +[Illustration: COMPRESSION CYLINDER. SCALE 1/60] + +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. + +[Illustration: Expansion Cylinder. Scale 1/60.92° F. temperature of +entering air. Cooling water entering in at 86° F.] + +[Illustration: Expansion Cylinder. Scale 1/60. 68° F. temperature of +entering air. Cooling water entering in at 65° F. 125 revs. per minute, +or 312 ft. per minute per piston speed.] + +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.-_The Engineer_. + +[Illustration: DRY AIR REFRIGERATING MACHINE] + + * * * * * + + + + +THOMAS'S IMPROVED STEAM WHEEL. + + +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. + +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. + +[Illustration: IMPROVED STEAM-WHEEL.] + +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. + + * * * * * + + + + +THE AMERICAN SOCIETY OF CIVIL ENGINEERS. + +ADDRESS OF THE PRESIDENT, JAMES BICHENO FRANCIS, AT THE THIRTEENTH +ANNUAL CONVENTION OF THE SOCIETY AT MONTREAL, JUNE 15, 1881. + + +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. + +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. + +The membership of the society is now as follows: + + Honorary members........ 11 + Corresponding members... 3 + Members................. 491 + Associates.............. 21 + Juniors................. 57 + Fellows................. 53 + ---- + Total................... 636 + +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. + +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. + +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. + + +WATER POWER. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +[Footnote 1: _Journal of the Franklin Institute_ for September, 1877.] + +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. + +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. + +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. + + +ANCHOR ICE. + +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. + +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. + +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 _regelation_, 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. + +[Footnote 1: Paper clx., in the Transactions of the Society, 1878, vol. +vii., pages 109-168.] + +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. + +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. + + * * * * * + + + + +A PAIR OF COTTAGES. + + +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.--_Building News_. + +[Illustration: SUGGESTIONS IN ARCHITECTURE.--A PAIR OF ENGLISH +COTTAGES.--BY A. CAWSTON.] + + * * * * * + + + + +DELICATE SCIENTIFIC INSTRUMENTS. + +By EDGAR L. LARKIN, New Windsor Observatory, New Windsor, Illinois. + + +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.) + +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 _its_ 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. + +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. + +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. + +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. + +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.) + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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." (_Science_, issue of Jan. 8,1881, p. 12.) It is expected to +reveal great facts concerning the heat of the stars. + +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. + +We cannot note the researches of Edison, Lockyer, or Tyndall, nor of +Crookes, who has seemingly reached the molecules whence the universe is +composed. + +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. + +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.--_Kansas Review_. + + * * * * * + + + + +THE FUTURE DEVELOPMENT OF ELECTRICAL APPLIANCES. + + +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. + +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. + +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: + +We Want to Use Water. We Want to Use Electricity. + +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. + +2. Energy available is 2. Energy available is +amount of water lifted x amount of electricity x difference +difference of level. of potential. + +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. + +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. + +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. + +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: + +ELECTRICAL MAGNITUDES (SOME RATHER APPROXIMATE). + +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 " + +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. + +Current measured by us in some experiments: + + 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 + +In any circuit, _current_ in webers = _electro-motive force_ in volts / +_resistance_ in ohms. + + +RATE OF PRODUCTION OF HEAT, CALCULATED IN THE SHAPE OF HORSE-POWER. + +In the whole of a circuit=_current_ in webers x _electro-motive force_ +in volts / 746. In any part of circuit=_current_ in webers x _difference +of potential_ 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. + +If there are a number of generators of electricity in a circuit, whose +electromotive forces in volts are E_1, E_2, etc., and if there are also +opposing electro-motive forces. F_1, F_2, 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: + + (E_1+E_2+etc.)-(F_1+F_2+etc.) +C = ----------------------------- + R + +[TEX: C = \frac{(E_1+E_2+\text{etc.})-(F_1+F_2+\text{etc.})}{R}] + + C C +P = ---((E_1+E_2+etc.); Q = ---(F_1+F_2+etc.) + 746 746 + +[TEX: \frac{C}{746}(E_1+E_2+\text{etc.});\ Q = +\frac{C}{746}(F_1+F_2+\text{etc.})] + + C² R +H = ----- . + 746 + +[TEX: H = \frac{C^2 R}{746}.] + +The lifting power of an electro-magnet of given volume is proportional +to the heat generated against resistance in the wire of the magnet. + +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. + +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." + +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: + +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: + + C=(E-F) / R + + P=E(E-F) / (746 R) + + Q=F(E-F) / (746 R) + + H=(E-F)_2 / (746 R) + + Q:H::F:E-F + +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. + +"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. + +"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." + +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. + + * * * * * + + + + +RESEARCHES ON THE RADIANT MATTER OF CROOKES AND THE MECHANICAL THEORY OF +ELECTRICITY. + +By DR. W. F. GINTL, abstracted by DR. VON GERICHTEN. + + +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 _sui generis,_ 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. + + * * * * * + + + + +ECONOMY OF THE ELECTRIC LIGHT. + + +Mr. W. H. Preece writes to the _Journal of Arts_ as follows: + +At the South Kensington Museum, very careful observations have been made +on the relative cost of the two systems, _i. e._, 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. + +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. + +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. + +The first outlay has been as follows: + +Engine and fixing, including shafting and +belting................................ £420 +Dynamo machine......................... 400 +Lamps, apparatus, and conducting wire . 384 + ------ + £1,204 + +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: + + £ s. d. +Carbons............................... 18 9 0 +Oil, etc.............................. 4 11 6 +Coal.................................. 11 14 0 +Wages................................. 34 7 6 + ---------- + £69 2 0 + +being at the rate of 3s. 10d. per hour of light. + +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. + +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-- + + £ 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 + +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. + +I am indebted to Colonel Festing, R.E., who has charge of the lighting, +for these details. + +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. + +"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." + +I am indebted for these facts to Mr. J. N. Shoolbred, under whose +supervision the arrangements were made. + +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. + +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. + +I am indebted for these facts to Mr. Humphreys, the manager of the +works. + +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. + + * * * * * + + + + +ON THE SPACE PROTECTED BY A LIGHTNING-CONDUCTOR. + +By WILLIAM HENRY PREECE. + +[Footnote: From the _Philosophical Magazine_ for December, 1880.] + + +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 _et seq._) showed how the distribution of the forces in any +electric field can be graphically depicted by drawing lines (which he +called _lines of force_) 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 _equipotential surface._ +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 _uniform field._ 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. + +[Illustration: Fig. 1] + +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. + +[Illustration: Fig. 2] + +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. + +[Illustration: Fig. 3] + +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, _e f_, would be +reached; disruptive discharge would take place, with its attendant +thunder and lightning. We can let the line, _e f_, 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. + +[Illustration: Fig. 4] + +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. + +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. + +[Illustration: Fig. 5] + +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. + +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. + +_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 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. + + * * * * * + + + + +PHOTO-ELECTRICITY OF FLUOR-SPAR CRYSTALS. + + +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.). + + * * * * * + + + + +THE AURORA BOREALIS AND TELEGRAPH CABLES. + + +The January and February numbers of the _Elektrotechnische Zeitschrift_ +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. + +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.--_Engineering_. + + * * * * * + + + + +THE PHOTOGRAPHIC IMAGE: WHAT IT IS. + +[Footnote: A communication to the Sheffield Photographic Society in the +_British Journal of Photography_.] + + +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. + +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. + +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_2Cl_2=Ag_2Cl+Cl. +When water is present the water is decomposed. Hydrochloric acid, HCl, +hypochlorous acid, HClO is formed. + +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_2Br_2=Ag_2Br+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. + +The theory regarding these sensitive salts of silver is that, being very +unstable, _i. e._, 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. + +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. + +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. + +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_4. 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. + +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. + +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. + +[Illustration: SECTION OF SENSITIVE PLATE AFTER EXPOSURE AND DURING +DEVELOPMENT. + +d Silver deposit--Image, c Sub-bromide and sub-chloride (gradations of), +b Collodion film--Substratum, a Section of glass plate--Support.] + +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_3 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. + +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. + +THOMAS H. MORTON, M.D. + + * * * * * + + + + +GELATINE TRANSPARENCIES FOR THE LANTERN. + +[Footnote: A communication to the Photographic Society of Ireland.] + + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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.--_Thomas Mayne, T. C., +in British Journal of Photography._ + + * * * * * + + + + +AN INTEGRATING MACHINE. + +[Footnote: Read at a meeting of the Physical Society, Feb. 26.] + + +By C.V. BOYS. + +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. + +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 _ascent_ made by the new curve +in passing from one ordinate to the other is a measure of the area +required. + +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. + +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 _drawn_. 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. + +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. + +[Illustration: AN INTEGRATING MACHINE.] + +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. + +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. + +Of the various curves exhibited which have been drawn by the machine, +the following are of special physical interest. + +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. + +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. + +Given the logarithmic curve y = e^x, 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. + +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. + +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. + +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, _crosses_ the axis of x, or +a point of inflexion unless A passes a maximum or minimum. + + * * * * * + + + + +UPON A MODIFICATION OF WHEATSTONE'S MICROPHONE AND ITS APPLICABILITY TO +RADIOPHONIC RESEARCHES. + +[Footnote: A paper read before the Philosophical Society of Washington. +D. C., June 11, 1881.] + +By ALEXANDER GRAHAM BELL. + + +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. + +[Footnote 1: Amer. Asso. for Advancement of Science, August 27, 1880.] + +[Footnote 2: _Nature_, vol. xxiii., p. 274.] + +[Footnote 3: Roy. Soc., Mar. 10, 1881.] + +[Illustration: Fig. 1. A B, Carbon Supports. C, Diaphragm.] + +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). + +[Footnote 1: April 21, 1881.] + +[Illustration: Fig. 2. A, Stiff wire. B, Diaphragm. C, Hearing tube. D, +Perforated handle.] + +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. + +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. + +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. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +Sent by mail, postage prepaid, to subscribers in any part of the United +States or Canada. Six dollars a year, sent, prepaid, to any foreign +country. + +All the back numbers of THE SUPPLEMENT, from the commencement, January +1, 1876, can be had. Price, 10 cents each. + +All the back volumes of THE SUPPLEMENT can likewise be supplied. Two +volumes are issued yearly. 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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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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: ASCII + +*** 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. + + + + + + + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 288 + + + + +NEW YORK, JULY 9, 1881 + +Scientific American Supplement. Vol. XI, No. 288. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + + TABLE OF CONTENTS. + +I. ENGINEERING AND MECHANICS--Dry Air Refrigerating Machine. + 5 figures. Plan, elevation, and diagrams of a new English + dry air refrigerator + + Thomas' Improved Steam Wheel. 1 figure + + 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 + +II. 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. + + Detection of Alcohol in Transparent Soaps. By H. JAY + + On the Calorific Power of Fuel, and on Thompson's Calorimeter. + By J.W. THOMAS + + Explosion as an Unknown Fire Hazard. A suggestive review of + the conditions of explosions, with curious examples + + Carbon. Symbol C. Combining weight. 12. By T. A. POOLEY + Second article on elementary chemistry written for brewers + + Manufacture of Soaps and their Production. By W. J. MENZIES + + The Preparation of Perfume Pomades. 1 figure. "Ensoufflage" + apparatus for perfumes + + Organic Matter in Sea Water + + Bacteria Life. Influence of heat and various gases and chemical + compounds on bacteria life + + On the Composition of Elephant's Milk. By Dr. CHAS. A. DOREMUS. + Comparison of elephant's milk with that of ten other mammals + + The Chemical Composition of Rice. Maize, and Barley. By J. STEINER + + Petroleum Oils. Character and properties of the various distillates + of crude petroleum. Fire risks attending the use of the + lighter petroleum oils + + Composition of the Petroleum of the Caucasus. By P. SCHULZENBERGER + and N. TONINE + + Notes on Cananga Oil. or Ilang-Ilang Oil. By F. A. FLUeCKIGER. + 1 figure. Flower and leaf of Cananga odorata + + Chian Turpentine, and the Tree which Produces It. By Dr. + STIEPOWICH. of Chios, Turkey + + On the Change of Volume which Accompanies the Galvanic Deposition + of a Metal. By M. E. BOUTY + + Analysis of the Rice Soils of Burmah. By R. ROMANIC, Chemical + Examiner, British Burmah + +III. 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 + + 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 + + The Future Development of Electrical Appliances. Lecture by + Prof. J. W. PERRY before the London Society of Arts.--Methods + and units of electrical measurements + + Researches on the Radiant Matter of Crookes and the Mechanical + Theory of Electricity. By Dr. W. F. GINTL + + Economy of the Electric Light. W. H. PREECE'S Experiments + Investigations + + On the Space Protected by a Lightning Conductor. By WM. H. + PREECE.--5 figures + + Photo-Electricity of Fluor Spar Crystals + + The Aurora Borealis and Telegraph Cables + + The Photographic Image: What It Is. By T. H. MORTON. + 1 figure.--Section of sensitive plate after exposure and during + development + + Gelatine Transparencies for the Lantern + + An Integrating Machine. By C. V. BOYS.--1 figure + + Upon a Modification of Wheatstone's Microphone and its + Applicability to Radiophonic Researches. + By ALEX. GRAHAM BELL,--2 figures + +IV. ARCHITECTURE.--Suggestions in Architecture, 1 figure.--A + pair of English cottages. By A. CAWSTON + + * * * * * + + + + +ALCOHOL IN NATURE--ITS PRESENCE IN THE EARTH, WATER, AND ATMOSPHERE. + + +A Chemist of merit, Mr. A. Muentz, 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. Muentz 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. + +[Footnote 1: The accompanying engravings have been made from drawings of +the apparatus in the laboratory of which Mr. Muentz is director, at the +Agronomic Institute.] + +[Illustration: FIG. 1.--FIRST DISTILLATORY APPARATUS.] + +[Illustration: FIG. 2.--SECOND DISTILLATORY APPARATUS.] + +Mr. Muentz'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. Muentz 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. + +[Illustration: Fig. 3.--IODOFORM CRYSTALS OBTAINED DIRECTLY (greatly +magnified).] + +[Illustration: FIG. 4,--IODOFORM CRYSTALS OBTAINED WITH RAIN WATER.] + +In the case of arable soil, Mr. Muentz 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. + +[Illustration: FIG. 5.--IODOFORM CRYSTALS OBTAINED WITH SNOW WATER.] + +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. Muentz 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. Muentz'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.--_La Nature_. + +[Illustration: FIG. 6.--IODOFORM CRYSTALS OBTAINED WITH VEGETABLE +MOULD.] + + * * * * * + + + + +DETECTION OF ALCOHOL IN TRANSPARENT SOAPS. + +By H. JAY. + + +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 1/2 c.c. sulphuric acid at 18 deg. 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 deg. 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. + + * * * * * + + + + +ON THE CALORIFIC POWER OF FUEL, AND ON THOMPSON'S CALORIMETER. + +By J.W. THOMAS, F.C.S., F.I.C. + + +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. + +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: + +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 deg. of rise in temperature only 10 deg. were recorded. + +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 deg., and the water at 60 deg., then the same coal would give a +like result with the water at 40 deg. and the room at 50 deg. 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 deg., when the water at starting +was 60 deg. and the room at 70 deg., gives 13.7 deg. rise of temperature with the +water at 40 deg. and the room at 50 deg. Conversely, when the water is at 70 deg. +and the room at 80 deg., 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. + +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): + + Composition per cent. + +Carbon...............................88.33 +Hydrogen............................. 5.08 +Oxygen............................... 3.28 +Nitrogen............................. 0.55 +Sulphur.............................. 0.70 +Ash.................................. 1.26 +Water (moisture)..................... 0.80 + ----- + 100.00 + +In the following experiments the standard temperature of the water was +taken as 60 deg. F., and as the coal gave 13.4 deg. of rise of temperature, 67 deg. +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 deg. F. rise of temperature, equal to +14.74 lb. of water per lb. of coal. When the water was at 50 deg. and +the room at 57 deg., the mean of several experiments gave 13.5 deg. rise of +temperature. When the water was 40 deg. at starting and the room at 47 deg., +13.65 deg. 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 deg., 40 deg., or at +intermediate temperatures. Without going much into detail, it was found +that when the temperature of the room was at 40 deg. and that of the water +40 deg., and the experiment was rapidly and carefully performed, 13.4 deg. rise +of temperature was given; but this result could be obtained without +special effort when the room was 42 deg. and the water 40 deg. 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 deg. above that +of the room. When the water was at 50 deg. and the room at 55 deg., the coal +gave 13.4 deg. 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 deg. and the room at 80 deg., 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. + +Taking the latent heat of steam as 537 deg. 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 _total heat units_ 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 deg. F. (the +temperature at which the _heat unit_ was determined). The temperature +of the room was about 60 deg., but this varied, as the weather was somewhat +severe and changeable. Under these conditions, with the water at 39 deg. and +room 60 deg., 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 deg. F. If, with the water at 60 deg., a +room were at 50 deg., 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 deg. and the water at 60 deg., 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 _all_ 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. + +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 _not_ 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 (31/2 inches long by 3/4 +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: + + Room at The water should be + + 80 deg. F. 70 deg. F. + 72 64 + 67 60 + 60 54 + 55 50 + 50 46 + 42 40 + +Say, for example, the room was at 57 deg. and the water placed in the +cylinder was at 46 deg.: add a little hot water and stir with the +thermometer until it assumes 52 deg. 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 deg. 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. + +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 3/4 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. + +By paying attention to such details, and following the method +recommended, the apparatus yields very satisfactory results with +bituminous and semi-bituminous coals.--_Chemical News_. + + * * * * * + + + + +EXPLOSION AS AN UNKNOWN FIRE HAZARD. + + +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 _noise_; it grew to comprehend the idea of _force_ +accompanied with violent outburst; it is advancing to a stage in which +it implies _combustion_ 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. + +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 _fire_ 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 _vs_. 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 _proximate_ cause; and if fire cause +explosion, and explosion cause loss, it is a loss by fire as _efficient_ +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." + +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 deg. 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. + +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. + +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. + +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 _rapid_ 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. + +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, _freely open to the air_. If ignited by a flame, however, in +an unconfined place, gun-cotton only burns with a strong blaze, but +if _confined_ where the temperature reaches 340 deg. F., it explodes with +terrific violence. Somewhat similar is the action of nitro-glycerine and +dynamite, which simply _burn_ if ignited in the open air, while the same +substance will _explode_ 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 deg. 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 _so long as the nail will continue +to enter the wood_. + +[Footnote 1: The purest gun-cotton may be regarded as a _cellulose_, +in which three atoms of hydrogen are replaced by three molecules of +peroxide of nitrogen.] + +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. + +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. + +"The germ of the first knowledge of an explosive was probably the +accidental discovery, ages ago, of the deflagrating property of the +natural saltpeter _when in contact with incandescent charcoal_."[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] + +[Footnote 1: Encyclopaedia Britannica, new edition, viii, p. 806.] + +[Footnote 2: _Vide_ Abel's Experiments in Gunpowder, as detailed in +Phil. Trans. Eoy. Soc, 1874.--_Vide_ also _Bull. Soc. d'Encouragement_, +Nov., 1880, p. 633, _Sur les Explosives_.] + +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_3) for the carbon of the charcoal, and the +production of carbonic acid gas (CO_2) 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_2 is reached. Considering +that water (H_2O) 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. + +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 _at_ 150 deg. 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 _warm or hot water_, 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 +_sea water_ was poured on them. + +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. + +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. + +Picric acid, the nature of which we have several times previously +mentioned, and which explodes at 600 deg. F. (only 28 deg. 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. + +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 +_employee_ 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. + +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. + +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 _hoisted_ up +and then squashed down." _Query:_ 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.--_American Exchange and +Review._ + + * * * * * + + + + +CARBON.--SYMBOL C.--COMBINING WEIGHT 12. + +By T.A. POOLEY, B.Sc., F.C.S. + + +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 _allotropism_, +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. + +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. + +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. + +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. + +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. + +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. + +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. + +_Carbon Dioxide, or Carbonic Acid, Symbol CO_2_.--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. + +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: + + CaCO_3 + 2HCl = CO_2 + H_2O + CaCl_2 + Calcium Hydrochloric Carbonic Water. Calcium +Carbonate. Acid. Acid. Chloride. + +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 deg. 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. + +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. + +_Carbon Monoxide, or Carbonic Oxide. Symbol CO._--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.--_Brewers' +Guardian._ + + * * * * * + + + + +SEYFFERTH'S PYROMETER. + + +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. + +[Illustration: Fig. 1.--Pyrometer with Electric Indicator.] + +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. + +[Illustration: Fig. 2.--Method of Mounting by means of a cone on vacuum +apparatus.] + +[Illustration: Fig. 3.--Mounting by means of a sleeve on vacuum +apparatus.] + +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. + +_Pyrometers filled with Ether._-These are tubular, and constructed of +yellow metal, and are graduated from 35 deg. C. to 120 deg. 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. + +_Pyrometers filled with distilled water_ are used for ascertaining +temperatures ranging from 100 deg. to 265 deg. C., 80 deg. to 210 deg. R., or 212 deg. to +510 deg. F. + +_Pyrometers filled with mercury_ are constructed for ascertaining +temperatures from 360 deg. to 750 deg. C. + +[Illustration: Fig. 4.--Mounting on horizontal pipes by thread on the +tube.] + +[Illustration: Fig. 5.--Mounting by means of a clasp in reservoirs.] + + +APPLICATION OF THE PYROMETER IN BONE BLACK FURNACES. + +The temperature necessary for the complete carbonization of the organic +substances of animal charcoal is from 430 deg. to 500 deg. 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 deg. +to 550 deg. If the heating of the animal black exceeds 500 deg. 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. + +The position that the pyrometer should occupy is subordinate to the +construction of the furnace. Fig. 6 shows the type which is most +employed. + +[Illustration: Fig. 6.--The Pyrometer mounted on a bone-black furnace.] + +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. + +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 deg. C. or +rises above 550 deg. C. + + +APPLICATION OF THE APPARATUS TO BRICK FURNACES AND IN THE MANUFACTURE OF +CHEMICAL PRODUCTS. + +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 deg., which is more than sufficient, since the temperature of the upper +part of a compartment fully exposed to the heat rarely exceeds 670 deg. to +680 deg. C. + +[Illustration: Fig. 7.--The Pyrometer mounted on a brick furnace.] + + * * * * * + + + + +MANUFACTURERS' SOAPS AND THEIR PRODUCTION. + +By W. J. MENZIES. + + +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. + +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. + +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. + +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 +_alkaline_ 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. + +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. + +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 deg. +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. + +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. + +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.--_Textile Manufacturer._ + + * * * * * + + + + +THE PREPARATION OF PERFUME POMADES. + + +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] + +[Footnote 1: Our illustration has been taken from C. Hofmann, +"Chemisch-technisches Universal-Receptbuch," 8vo, Berlin, 1879, p. 207.] + +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.--_New Remedies._ + +[Illustration: "ENSOUFFLAGE" APPARATUS FOR PERFUMES.] + + * * * * * + + + + +ORGANIC MATTER IN SEA-WATER. + + +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 (_Chem. Soc. Journ_., 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. + + * * * * * + + + + +BACTERIA LIFE. + + +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 1/4 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 Muentz, that bacteria cannot exist in the presence of +21/2 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 +1/4 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. + +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 deg. 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. + + * * * * * + + + + +ON THE COMPOSITION OF ELEPHANTS' MILK. + +[Footnote: Read before the American Chemical Society, June 3,1881.] + +By CHAS. A. DOREMUS, M.D., Ph.D. + + +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. + +Through the courtesy of Jas. A. Bailey I was enabled to procure samples +of the milk on several occasions. + +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. + +When born the calf weighed 2131/2 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. + +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. + +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. + +The following represents approximately the daily diet of the mother: + +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. + +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. + +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. + +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. + +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. + +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: + + + No. I. II. III. + April 5, April 9, April 10, + Morning. Noon. Morning. + + Quantity, 19 cc. 36 cc. 72 cc. + Cream, 52-4, vol.% 58 62 + Reaction, Neutral. Slightly alkaline. Slightly acid. + Sp.gr., ---- ---- 1023.7 + + 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 + + +Ten grammes were taken for analysis, and in No. III. duplicates were +made. + +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. + +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. + +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. + +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. + +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. + +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. + +[Footnote 1: "Lehrhuch der Physiologischen Chemie," pp. 423 and 424.] + +Constituents. Woman. Cow. Goat. Ewe. Ass. Mare. + +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 + +Constituents. Buffalo. Camel. Sow. Hippo- Elephant. + potamus. + +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 + +[Footnote 1: Milk Sugar included.] + +It may be remarked that though approaching the composition of cream it +still differs enough to require it to be considered milk. + +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. + +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 deg. C. or 64 deg. F. + +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. + +In size the "Baby" compared equally with other elephants in the same +menagerie, who were known to be four and five years old. + +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. + + * * * * * + + + + +THE CHEMICAL COMPOSITION OF RICE, MAIZE, AND BARLEY. + +By J. STEINER, F.C.S. + + +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. + +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: + + Barley. Maize. Rice. + -------------- ------------- ------------------ + Air Dried at Air Dried at Air Dried at With + Dry. 100 deg. C. Dry. 100 deg. C. Dry. 100 deg. C. Husk. + +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 + +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. + +But on the other hand, barley and maize are richer in albuminous matter +and in ash. The extractive matter, _i. e._, 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). + +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. + + 100 parts of + Potash Lime Magnesia Phosphoric Silica grain contain + acid ash. + +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 " + +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. + +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.--_London +Brewers' Journal._ + + * * * * * + + + + +PETROLEUM OILS. + + +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. + +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. + +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. + +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 _per se_, 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. + +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.--_Fireman's Journal_ + + * * * * * + + + + +COMPOSITION OF THE PETROLEUM OF THE CAUCASUS. + +By MM. P SCHUTZENBERGER and N. TONINE. + + +All portions of this petroleum contain saturated carbides of the formula +C_nH_{2n}, which the authors name paraffenes. At a bright red heat they +yield benzinic carbides, C_nH_{2n-6}, 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. + + * * * * * + + + + +NOTES ON CANANGA OIL OR ILANG-ILANG OIL. + +[Footnote: From the _Archiv der Pharmacie_.] + +By F. A. FLUeCKIGER. + + +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. + +The tree, of which the flowers yield the oil known under the name +"Ilang-ilang" or "Alanguilan," is the _Cananga odorata_, Hook. fil. et +Thomp.,[1] of the order Unonaceae, for which reason it is called also in +many price lists "Oleum Anonae," or "Oleum Unonae" 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 Lucon[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, _Uvaria odorata_." According to Roxburgh,[6] +the plant was in 1797 brought from Sumatra to the Botanical Gardens in +Calcutta. Dunal devoted to the _Ucaria odorata_, or, properly, _Unona +odorata_, 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. + +[Footnote 1: "Flora Indica," i (1855), 130.] + +[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, _New Remedies_, April, 1881, page 98.] + +[Footnote 3: Ray. "Historia Plantarum, Supplementum," tomi i et ii +"Hist. Stirpium Insulae Luzonensis et Philippinarum" a Georgio Josepho +Canello; London, 1704, 83] + +[Footnote 4: "Herbarium Amboinense, Amboinsch Kruidboek," ii. +(Amsterdam, 1750), cap. xix, fol. 195 and tab. 65.] + +[Footnote 5: "Encyclopedie methodique. Botanique," i (1783), 595.] + +[Footnote 6: "Flora Indica," ii. (Serampore, 1832), 661.] + +[Footnote 7: Paris, 1817, p. 108, 105.] + +Lastly, we owe a very handsome figure of the _Cananga odorata_ to the +magnificent "Flora Javae," 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 _Unona odoratissima_, 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 _Uvaria_, from which he would not +separate the Ilang-ilang tree. + +[Footnote 1: Vol. i. (Brussels, 1829), fol. 29, tab ix et xiv. B.] + +[Footnote 2: "Flora de Filipinas," Manila, 1845, 325. _Unona +odoratissima_, 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.] + +[Footnote 3: "Dictionnaire de Botanique."] + +[Illustration: CANAGA ODORATA] + +The notice of Maximowicz,[1] "Ueber den Ursprung des Parfums +Ylang-Ylang," contains only a confirmation of the derivation of the +perfume from Cananga. + +[Footnote 1: Just's "Botanischer Jahresbericht," 1875, 973.] + +_Cananga odorata_ 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 _Cananga odorata_ 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. + +_Cananga odorata_, 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 _Unona_ or _Uvaria_, among +which some equally possess odorous flowers, are now distributed between +those two genera, which are tolerably rich in species. From _Uvaria_ +the _Cananga_ differs in its valvate petals, and from _Unona_ in the +arrangement of the seeds in two rows. + +[Footnote 1: "Genera Plantarum," i, (1864), 24.] + +_Cananga odorata_ 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 _Michelia champaca_, L.,[1] of the +family Magnoliaceae, 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" (_Michelia champaca_) and the "Kenangga wangi" +(_Cananga odorata_)[2] stand in the first rank. + +[Footnote 1: A beautiful figure of this also is given in Blume's "Flora +Javae," iii., Magnoliaceae, tab. I.] + +[Footnote 2: Junghuhn, Java, Leipsic, 1852, 166.] + +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] + +[Footnote 1: _Jahresbericht d. Pharmacie_, by Wiggers and Husemann, +1867, 422.] + +[Footnote 2: _Jahresbericht_, 1868, 166.] + +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 _Michelia champaca_, 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 (L30) 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. + +[Footnote 1: _Archiv der Pharmacie_, ccxiv. (1879), 18.] + +[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).] + +[Footnote 3: 25 grammes of oil from 5 kilogrammes of flowers, according +to Reymann.] + +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 _Cananga odorata_ and _Michelia champaca_, and colored +yellow by means of turmeric. In India unguents of this kind have always +been in use. + +[Footnote 1: _Histoire Naturelle des Drogues Simples_, iii. (1850), +675.] + +The name "Cananga" is met with in Germany as occurring in former times. +An "Oleum destillatum Canangae" 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 Laendern 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 _Cananga odorata_, +the fruit-pulp of which is expressly described by Humph and by Blume as +sweetish. Further an "Oleum Canangae, 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 _Andropogon +laniger_. + +[Footnote 1: Compare Flueckiger, "Pharmakognosic," 2d edit, 1881, p. +152.] + +[Footnote 2: Flueckiger, "Documente zur Geschichte der Pharmacie," Halle +(1876), p 93.] + +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 deg. C.; but the thermometer rose gradually to 290 deg., and at a still +higher temperature decomposition commenced. That the portions passing +over below 290 deg. 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 deg. 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. + +[Footnote 1: _Comptes Rendus_, lxxvi. (1873), 1428, and abstracted in +the _Pharmaceutical Journal_ [3], iv., p. 28; also in _Jahresbericht_, +1873, p. 431.] + +[Footnote 2: Overlooking Peru balsam and Tolu balsam.] + +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. + + * * * * * + + + + +CHIAN TURPENTINE. + + +The following letter has been received by the editors of the _Repertoire +de Pharmacie:_ 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. + +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. + +The turpentine tree (_Pistacia terebinthus_ 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. + +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. + +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. + +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 +(_Pistacia lentiscus_ 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. + +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. + +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., + +DR. STIEPOWICH. + +Chio, Turkey. + + * * * * * + + + + +ON THE CHANGE OF VOLUME WHICH ACCOMPANIES THE GALVANIC DEPOSITION OF A +METAL. + +By M. E. BOUTY. + + +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 _neutral point of temperatures_. + +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 _neutral point +of compression_ 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. + +I have determined, by the help of observations made with ten different +current strengths, the constants of the formulae 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: + + A t + (1) y = ------- + B + t + +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: + + (2) A = - a'i + b'i squared, + +of the same form as the expression E: + + E = - ai + bi squared, + +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. + +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.--_Comptes Rendus._ + + * * * * * + + + + +ANALYSES OF RICE SOILS FROM BURMAH. + +By R. ROMANIS, D.Sc., Chemical Examiner, British Burmah. + + +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. + +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. + +Results of two analyses of soils from Syriam, near Rangoon, are +appended: + + _Soluble in Hydrochloric Acid_. + + 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 + + _Soluble in Sulphuric Acid_. + +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 + + _Residue_. + +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 + +These are alluvial soils from the Delta of the Irrawaddy. + + * * * * * + + + + +DRY AIR REFRIGERATING MACHINE. + + +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! + +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. + +[Illustration: COMPRESSION CYLINDER. SCALE 1/60] + +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. + +[Illustration: Expansion Cylinder. Scale 1/60.92 deg. F. temperature of +entering air. Cooling water entering in at 86 deg. F.] + +[Illustration: Expansion Cylinder. Scale 1/60. 68 deg. F. temperature of +entering air. Cooling water entering in at 65 deg. F. 125 revs. per minute, +or 312 ft. per minute per piston speed.] + +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.-_The Engineer_. + +[Illustration: DRY AIR REFRIGERATING MACHINE] + + * * * * * + + + + +THOMAS'S IMPROVED STEAM WHEEL. + + +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. + +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. + +[Illustration: IMPROVED STEAM-WHEEL.] + +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. + + * * * * * + + + + +THE AMERICAN SOCIETY OF CIVIL ENGINEERS. + +ADDRESS OF THE PRESIDENT, JAMES BICHENO FRANCIS, AT THE THIRTEENTH +ANNUAL CONVENTION OF THE SOCIETY AT MONTREAL, JUNE 15, 1881. + + +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. + +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. + +The membership of the society is now as follows: + + Honorary members........ 11 + Corresponding members... 3 + Members................. 491 + Associates.............. 21 + Juniors................. 57 + Fellows................. 53 + ---- + Total................... 636 + +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. + +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. + +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. + + +WATER POWER. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +[Footnote 1: _Journal of the Franklin Institute_ for September, 1877.] + +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. + +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. + +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. + + +ANCHOR ICE. + +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. + +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. + +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 _regelation_, 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. + +[Footnote 1: Paper clx., in the Transactions of the Society, 1878, vol. +vii., pages 109-168.] + +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. + +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. + + * * * * * + + + + +A PAIR OF COTTAGES. + + +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.--_Building News_. + +[Illustration: SUGGESTIONS IN ARCHITECTURE.--A PAIR OF ENGLISH +COTTAGES.--BY A. CAWSTON.] + + * * * * * + + + + +DELICATE SCIENTIFIC INSTRUMENTS. + +By EDGAR L. LARKIN, New Windsor Observatory, New Windsor, Illinois. + + +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 nebulae, 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.) + +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 _its_ 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, faculae, +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 deg. 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. + +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. + +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. + +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. + +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.) + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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." (_Science_, issue of Jan. 8,1881, p. 12.) It is expected to +reveal great facts concerning the heat of the stars. + +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 deg., 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. + +We cannot note the researches of Edison, Lockyer, or Tyndall, nor of +Crookes, who has seemingly reached the molecules whence the universe is +composed. + +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. + +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.--_Kansas Review_. + + * * * * * + + + + +THE FUTURE DEVELOPMENT OF ELECTRICAL APPLIANCES. + + +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. + +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. + +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: + +We Want to Use Water. We Want to Use Electricity. + +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. + +2. Energy available is 2. Energy available is +amount of water lifted x amount of electricity x difference +difference of level. of potential. + +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. + +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. + +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. + +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: + +ELECTRICAL MAGNITUDES (SOME RATHER APPROXIMATE). + +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 " + +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. + +Current measured by us in some experiments: + + 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 + +In any circuit, _current_ in webers = _electro-motive force_ in volts / +_resistance_ in ohms. + + +RATE OF PRODUCTION OF HEAT, CALCULATED IN THE SHAPE OF HORSE-POWER. + +In the whole of a circuit=_current_ in webers x _electro-motive force_ +in volts / 746. In any part of circuit=_current_ in webers x _difference +of potential_ 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. + +If there are a number of generators of electricity in a circuit, whose +electromotive forces in volts are E_1, E_2, etc., and if there are also +opposing electro-motive forces. F_1, F_2, 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: + + (E_1+E_2+etc.)-(F_1+F_2+etc.) +C = ----------------------------- + R + +[TEX: C = \frac{(E_1+E_2+\text{etc.})-(F_1+F_2+\text{etc.})}{R}] + + C C +P = ---((E_1+E_2+etc.); Q = ---(F_1+F_2+etc.) + 746 746 + +[TEX: \frac{C}{746}(E_1+E_2+\text{etc.});\ Q = +\frac{C}{746}(F_1+F_2+\text{etc.})] + + C squared R +H = ----- . + 746 + +[TEX: H = \frac{C^2 R}{746}.] + +The lifting power of an electro-magnet of given volume is proportional +to the heat generated against resistance in the wire of the magnet. + +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. + +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." + +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: + +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: + + C=(E-F) / R + + P=E(E-F) / (746 R) + + Q=F(E-F) / (746 R) + + H=(E-F)_2 / (746 R) + + Q:H::F:E-F + +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. + +"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. + +"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." + +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. + + * * * * * + + + + +RESEARCHES ON THE RADIANT MATTER OF CROOKES AND THE MECHANICAL THEORY OF +ELECTRICITY. + +By DR. W. F. GINTL, abstracted by DR. VON GERICHTEN. + + +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 _sui generis,_ 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. + + * * * * * + + + + +ECONOMY OF THE ELECTRIC LIGHT. + + +Mr. W. H. Preece writes to the _Journal of Arts_ as follows: + +At the South Kensington Museum, very careful observations have been made +on the relative cost of the two systems, _i. e._, 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. + +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. + +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. + +The first outlay has been as follows: + +Engine and fixing, including shafting and +belting................................ L420 +Dynamo machine......................... 400 +Lamps, apparatus, and conducting wire . 384 + ------ + L1,204 + +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: + + L s. d. +Carbons............................... 18 9 0 +Oil, etc.............................. 4 11 6 +Coal.................................. 11 14 0 +Wages................................. 34 7 6 + ---------- + L69 2 0 + +being at the rate of 3s. 10d. per hour of light. + +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 L426 per annum. + +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 L994. 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-- + + L 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.......... L109 10 + +leaving a handsome balance to the good of L316 10s. as against gas. The +results of the working, both practically and financially, have proved to +be, at South Kensington, a decided success. + +I am indebted to Colonel Festing, R.E., who has charge of the lighting, +for these details. + +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. + +"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 11/2d. 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." + +I am indebted for these facts to Mr. J. N. Shoolbred, under whose +supervision the arrangements were made. + +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 L8 9s. per week, the electric light has been adopted at +an expenditure of L4 14s. per week. + +The erecting shop, 450 feet by 150 feet, formerly dimly lit by gas at a +cost of L22 per week, is now efficiently lit by electricity at half the +cost. + +I am indebted for these facts to Mr. Humphreys, the manager of the +works. + +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. + + * * * * * + + + + +ON THE SPACE PROTECTED BY A LIGHTNING-CONDUCTOR. + +By WILLIAM HENRY PREECE. + +[Footnote: From the _Philosophical Magazine_ for December, 1880.] + + +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., Sec. 3122 _et seq._) showed how the distribution of the forces in any +electric field can be graphically depicted by drawing lines (which he +called _lines of force_) 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 _equipotential surface._ +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 _uniform field._ 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. + +[Illustration: Fig. 1] + +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. + +[Illustration: Fig. 2] + +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. + +[Illustration: Fig. 3] + +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, _e f_, would be +reached; disruptive discharge would take place, with its attendant +thunder and lightning. We can let the line, _e f_, 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. + +[Illustration: Fig. 4] + +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. + +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. + +[Illustration: Fig. 5] + +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. + +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. + +_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 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. + + * * * * * + + + + +PHOTO-ELECTRICITY OF FLUOR-SPAR CRYSTALS. + + +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 deg. to 100 deg. C.). + + * * * * * + + + + +THE AURORA BOREALIS AND TELEGRAPH CABLES. + + +The January and February numbers of the _Elektrotechnische Zeitschrift_ +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 deg. 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 +Leclanche cells. + +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.--_Engineering_. + + * * * * * + + + + +THE PHOTOGRAPHIC IMAGE: WHAT IT IS. + +[Footnote: A communication to the Sheffield Photographic Society in the +_British Journal of Photography_.] + + +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. + +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. + +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_2Cl_2=Ag_2Cl+Cl. +When water is present the water is decomposed. Hydrochloric acid, HCl, +hypochlorous acid, HClO is formed. + +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_2Br_2=Ag_2Br+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. + +The theory regarding these sensitive salts of silver is that, being very +unstable, _i. e._, 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. + +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. + +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. + +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_4. 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. + +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. + +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. + +[Illustration: SECTION OF SENSITIVE PLATE AFTER EXPOSURE AND DURING +DEVELOPMENT. + +d Silver deposit--Image, c Sub-bromide and sub-chloride (gradations of), +b Collodion film--Substratum, a Section of glass plate--Support.] + +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_3 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. + +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. + +THOMAS H. MORTON, M.D. + + * * * * * + + + + +GELATINE TRANSPARENCIES FOR THE LANTERN. + +[Footnote: A communication to the Photographic Society of Ireland.] + + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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.--_Thomas Mayne, T. C., +in British Journal of Photography._ + + * * * * * + + + + +AN INTEGRATING MACHINE. + +[Footnote: Read at a meeting of the Physical Society, Feb. 26.] + + +By C.V. BOYS. + +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. + +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 _ascent_ made by the new curve +in passing from one ordinate to the other is a measure of the area +required. + +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. + +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 _drawn_. 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. + +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. + +[Illustration: AN INTEGRATING MACHINE.] + +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. + +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. + +Of the various curves exhibited which have been drawn by the machine, +the following are of special physical interest. + +Given the inclined straight line y = cx, the machine draws the parabola +y = cx squared / 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. + +Given the curve representing attraction y = 1 / x squared 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. + +Given the logarithmic curve y = e^x, 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. + +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. + +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. + +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, _crosses_ the axis of x, or +a point of inflexion unless A passes a maximum or minimum. + + * * * * * + + + + +UPON A MODIFICATION OF WHEATSTONE'S MICROPHONE AND ITS APPLICABILITY TO +RADIOPHONIC RESEARCHES. + +[Footnote: A paper read before the Philosophical Society of Washington. +D. C., June 11, 1881.] + +By ALEXANDER GRAHAM BELL. + + +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. + +[Footnote 1: Amer. Asso. for Advancement of Science, August 27, 1880.] + +[Footnote 2: _Nature_, vol. xxiii., p. 274.] + +[Footnote 3: Roy. Soc., Mar. 10, 1881.] + +[Illustration: Fig. 1. A B, Carbon Supports. C, Diaphragm.] + +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). + +[Footnote 1: April 21, 1881.] + +[Illustration: Fig. 2. A, Stiff wire. B, Diaphragm. C, Hearing tube. D, +Perforated handle.] + +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. + +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. + +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. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +Sent by mail, postage prepaid, to subscribers in any part of the United +States or Canada. Six dollars a year, sent, prepaid, to any foreign +country. + +All the back numbers of THE SUPPLEMENT, from the commencement, January +1, 1876, can be had. Price, 10 cents each. + +All the back volumes of THE SUPPLEMENT can likewise be supplied. Two +volumes are issued yearly. 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You can also find out about how to make a +donation to Project Gutenberg, and how to get involved. + + +**Welcome To The World of Free Plain Vanilla Electronic Texts** + +**eBooks Readable By Both Humans and By Computers, Since 1971** + +*****These eBooks Were Prepared By Thousands of Volunteers!***** + + +Title: Scientific American Supplement, No. 288 + July 9, 1881 + +Author: Various + +Release Date: June, 2005 [EBook #8391] +[Yes, we are more than one year ahead of schedule] +[This file was first posted on July 6, 2003] + +Edition: 10 + +Language: English + +Character set encoding: ASCII + +*** START OF THE PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN NO. 288 *** + + + + +Olaf Voss, Don Kretz, Juliet Sutherland, +Charles Franks and the Online Distributed Proofreading Team. + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 288 + + + + +NEW YORK, JULY 9, 1881 + +Scientific American Supplement. Vol. XI, No. 288. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + + TABLE OF CONTENTS. + +I. ENGINEERING AND MECHANICS--Dry Air Refrigerating Machine. + 5 figures. Plan, elevation, and diagrams of a new English + dry air refrigerator + + Thomas' Improved Steam Wheel. 1 figure + + 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 + +II. 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. + + Detection of Alcohol in Transparent Soaps. By H. JAY + + On the Calorific Power of Fuel, and on Thompson's Calorimeter. + By J.W. THOMAS + + Explosion as an Unknown Fire Hazard. A suggestive review of + the conditions of explosions, with curious examples + + Carbon. Symbol C. Combining weight. 12. By T. A. POOLEY + Second article on elementary chemistry written for brewers + + Manufacture of Soaps and their Production. By W. J. MENZIES + + The Preparation of Perfume Pomades. 1 figure. "Ensoufflage" + apparatus for perfumes + + Organic Matter in Sea Water + + Bacteria Life. Influence of heat and various gases and chemical + compounds on bacteria life + + On the Composition of Elephant's Milk. By Dr. CHAS. A. DOREMUS. + Comparison of elephant's milk with that of ten other mammals + + The Chemical Composition of Rice. Maize, and Barley. By J. STEINER + + Petroleum Oils. Character and properties of the various distillates + of crude petroleum. Fire risks attending the use of the + lighter petroleum oils + + Composition of the Petroleum of the Caucasus. By P. SCHULZENBERGER + and N. TONINE + + Notes on Cananga Oil. or Ilang-Ilang Oil. By F. A. FLUeCKIGER. + 1 figure. Flower and leaf of Cananga odorata + + Chian Turpentine, and the Tree which Produces It. By Dr. + STIEPOWICH. of Chios, Turkey + + On the Change of Volume which Accompanies the Galvanic Deposition + of a Metal. By M. E. BOUTY + + Analysis of the Rice Soils of Burmah. By R. ROMANIC, Chemical + Examiner, British Burmah + +III. 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 + + 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 + + The Future Development of Electrical Appliances. Lecture by + Prof. J. W. PERRY before the London Society of Arts.--Methods + and units of electrical measurements + + Researches on the Radiant Matter of Crookes and the Mechanical + Theory of Electricity. By Dr. W. F. GINTL + + Economy of the Electric Light. W. H. PREECE'S Experiments + Investigations + + On the Space Protected by a Lightning Conductor. By WM. H. + PREECE.--5 figures + + Photo-Electricity of Fluor Spar Crystals + + The Aurora Borealis and Telegraph Cables + + The Photographic Image: What It Is. By T. H. MORTON. + 1 figure.--Section of sensitive plate after exposure and during + development + + Gelatine Transparencies for the Lantern + + An Integrating Machine. By C. V. BOYS.--1 figure + + Upon a Modification of Wheatstone's Microphone and its + Applicability to Radiophonic Researches. + By ALEX. GRAHAM BELL,--2 figures + +IV. ARCHITECTURE.--Suggestions in Architecture, 1 figure.--A + pair of English cottages. By A. CAWSTON + + * * * * * + + + + +ALCOHOL IN NATURE--ITS PRESENCE IN THE EARTH, WATER, AND ATMOSPHERE. + + +A Chemist of merit, Mr. A. Muentz, 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. Muentz 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. + +[Footnote 1: The accompanying engravings have been made from drawings of +the apparatus in the laboratory of which Mr. Muentz is director, at the +Agronomic Institute.] + +[Illustration: FIG. 1.--FIRST DISTILLATORY APPARATUS.] + +[Illustration: FIG. 2.--SECOND DISTILLATORY APPARATUS.] + +Mr. Muentz'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. Muentz 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. + +[Illustration: Fig. 3.--IODOFORM CRYSTALS OBTAINED DIRECTLY (greatly +magnified).] + +[Illustration: FIG. 4,--IODOFORM CRYSTALS OBTAINED WITH RAIN WATER.] + +In the case of arable soil, Mr. Muentz 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. + +[Illustration: FIG. 5.--IODOFORM CRYSTALS OBTAINED WITH SNOW WATER.] + +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. Muentz 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. Muentz'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.--_La Nature_. + +[Illustration: FIG. 6.--IODOFORM CRYSTALS OBTAINED WITH VEGETABLE +MOULD.] + + * * * * * + + + + +DETECTION OF ALCOHOL IN TRANSPARENT SOAPS. + +By H. JAY. + + +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 1/2 c.c. sulphuric acid at 18 deg. 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 deg. 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. + + * * * * * + + + + +ON THE CALORIFIC POWER OF FUEL, AND ON THOMPSON'S CALORIMETER. + +By J.W. THOMAS, F.C.S., F.I.C. + + +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. + +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: + +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 deg. of rise in temperature only 10 deg. were recorded. + +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 deg., and the water at 60 deg., then the same coal would give a +like result with the water at 40 deg. and the room at 50 deg.. 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 deg., when the water at starting +was 60 deg. and the room at 70 deg., gives 13.7 deg. rise of temperature with the +water at 40 deg. and the room at 50 deg.. Conversely, when the water is at 70 deg. +and the room at 80 deg., 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. + +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): + + Composition per cent. + +Carbon...............................88.33 +Hydrogen............................. 5.08 +Oxygen............................... 3.28 +Nitrogen............................. 0.55 +Sulphur.............................. 0.70 +Ash.................................. 1.26 +Water (moisture)..................... 0.80 + ----- + 100.00 + +In the following experiments the standard temperature of the water was +taken as 60 deg. F., and as the coal gave 13.4 deg. of rise of temperature, 67 deg. +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 deg. F. rise of temperature, equal to +14.74 lb. of water per lb. of coal. When the water was at 50 deg. and +the room at 57 deg., the mean of several experiments gave 13.5 deg. rise of +temperature. When the water was 40 deg. at starting and the room at 47 deg., +13.65 deg. 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 deg., 40 deg., or at +intermediate temperatures. Without going much into detail, it was found +that when the temperature of the room was at 40 deg. and that of the water +40 deg., and the experiment was rapidly and carefully performed, 13.4 deg. rise +of temperature was given; but this result could be obtained without +special effort when the room was 42 deg. and the water 40 deg. 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 deg. above that +of the room. When the water was at 50 deg. and the room at 55 deg., the coal +gave 13.4 deg. 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 deg. and the room at 80 deg., 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. + +Taking the latent heat of steam as 537 deg. 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 _total heat units_ 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 deg. F. (the +temperature at which the _heat unit_ was determined). The temperature +of the room was about 60 deg., but this varied, as the weather was somewhat +severe and changeable. Under these conditions, with the water at 39 deg. and +room 60 deg., 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 deg. F. If, with the water at 60 deg., a +room were at 50 deg., 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 deg. and the water at 60 deg., 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 _all_ 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. + +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 _not_ 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 (31/2 inches long by 3/4 +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: + + Room at The water should be + + 80 deg. F. 70 deg. F. + 72 64 + 67 60 + 60 54 + 55 50 + 50 46 + 42 40 + +Say, for example, the room was at 57 deg. and the water placed in the +cylinder was at 46 deg.: add a little hot water and stir with the +thermometer until it assumes 52 deg.. 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 deg.. 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. + +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 3/4 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. + +By paying attention to such details, and following the method +recommended, the apparatus yields very satisfactory results with +bituminous and semi-bituminous coals.--_Chemical News_. + + * * * * * + + + + +EXPLOSION AS AN UNKNOWN FIRE HAZARD. + + +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 _noise_; it grew to comprehend the idea of _force_ +accompanied with violent outburst; it is advancing to a stage in which +it implies _combustion_ 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. + +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 _fire_ 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 _vs_. 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 _proximate_ cause; and if fire cause +explosion, and explosion cause loss, it is a loss by fire as _efficient_ +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." + +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 deg. 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. + +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. + +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. + +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 _rapid_ 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. + +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, _freely open to the air_. If ignited by a flame, however, in +an unconfined place, gun-cotton only burns with a strong blaze, but +if _confined_ where the temperature reaches 340 deg. F., it explodes with +terrific violence. Somewhat similar is the action of nitro-glycerine and +dynamite, which simply _burn_ if ignited in the open air, while the same +substance will _explode_ 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 deg. 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 _so long as the nail will continue +to enter the wood_. + +[Footnote 1: The purest gun-cotton may be regarded as a _cellulose_, +in which three atoms of hydrogen are replaced by three molecules of +peroxide of nitrogen.] + +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. + +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. + +"The germ of the first knowledge of an explosive was probably the +accidental discovery, ages ago, of the deflagrating property of the +natural saltpeter _when in contact with incandescent charcoal_."[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] + +[Footnote 1: Encyclopaedia Britannica, new edition, viii, p. 806.] + +[Footnote 2: _Vide_ Abel's Experiments in Gunpowder, as detailed in +Phil. Trans. Eoy. Soc, 1874.--_Vide_ also _Bull. Soc. d'Encouragement_, +Nov., 1880, p. 633, _Sur les Explosives_.] + +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_3) for the carbon of the charcoal, and the +production of carbonic acid gas (CO_2) 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_2 is reached. Considering +that water (H_2O) 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. + +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 _at_ 150 deg. 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 _warm or hot water_, 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 +_sea water_ was poured on them. + +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. + +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. + +Picric acid, the nature of which we have several times previously +mentioned, and which explodes at 600 deg. F. (only 28 deg. 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. + +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 +_employee_ 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. + +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. + +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 _hoisted_ up +and then squashed down." _Query:_ 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.--_American Exchange and +Review._ + + * * * * * + + + + +CARBON.--SYMBOL C.--COMBINING WEIGHT 12. + +By T.A. POOLEY, B.Sc., F.C.S. + + +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 _allotropism_, +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. + +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. + +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. + +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. + +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. + +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. + +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. + +_Carbon Dioxide, or Carbonic Acid, Symbol CO_2_.--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. + +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: + + CaCO_3 + 2HCl = CO_2 + H_2O + CaCl_2 + Calcium Hydrochloric Carbonic Water. Calcium +Carbonate. Acid. Acid. Chloride. + +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 deg. 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. + +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. + +_Carbon Monoxide, or Carbonic Oxide. Symbol CO._--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.--_Brewers' +Guardian._ + + * * * * * + + + + +SEYFFERTH'S PYROMETER. + + +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. + +[Illustration: Fig. 1.--Pyrometer with Electric Indicator.] + +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. + +[Illustration: Fig. 2.--Method of Mounting by means of a cone on vacuum +apparatus.] + +[Illustration: Fig. 3.--Mounting by means of a sleeve on vacuum +apparatus.] + +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. + +_Pyrometers filled with Ether._-These are tubular, and constructed of +yellow metal, and are graduated from 35 deg. C. to 120 deg.. 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. + +_Pyrometers filled with distilled water_ are used for ascertaining +temperatures ranging from 100 deg. to 265 deg. C., 80 deg. to 210 deg. R., or 212 deg. to +510 deg. F. + +_Pyrometers filled with mercury_ are constructed for ascertaining +temperatures from 360 deg. to 750 deg. C. + +[Illustration: Fig. 4.--Mounting on horizontal pipes by thread on the +tube.] + +[Illustration: Fig. 5.--Mounting by means of a clasp in reservoirs.] + + +APPLICATION OF THE PYROMETER IN BONE BLACK FURNACES. + +The temperature necessary for the complete carbonization of the organic +substances of animal charcoal is from 430 deg. to 500 deg. 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 deg. +to 550 deg.. If the heating of the animal black exceeds 500 deg. 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. + +The position that the pyrometer should occupy is subordinate to the +construction of the furnace. Fig. 6 shows the type which is most +employed. + +[Illustration: Fig. 6.--The Pyrometer mounted on a bone-black furnace.] + +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. + +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 deg. C. or +rises above 550 deg. C. + + +APPLICATION OF THE APPARATUS TO BRICK FURNACES AND IN THE MANUFACTURE OF +CHEMICAL PRODUCTS. + +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 deg., which is more than sufficient, since the temperature of the upper +part of a compartment fully exposed to the heat rarely exceeds 670 deg. to +680 deg. C. + +[Illustration: Fig. 7.--The Pyrometer mounted on a brick furnace.] + + * * * * * + + + + +MANUFACTURERS' SOAPS AND THEIR PRODUCTION. + +By W. J. MENZIES. + + +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. + +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. + +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. + +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 +_alkaline_ 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. + +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. + +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 deg. +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. + +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. + +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.--_Textile Manufacturer._ + + * * * * * + + + + +THE PREPARATION OF PERFUME POMADES. + + +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] + +[Footnote 1: Our illustration has been taken from C. Hofmann, +"Chemisch-technisches Universal-Receptbuch," 8vo, Berlin, 1879, p. 207.] + +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.--_New Remedies._ + +[Illustration: "ENSOUFFLAGE" APPARATUS FOR PERFUMES.] + + * * * * * + + + + +ORGANIC MATTER IN SEA-WATER. + + +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 (_Chem. Soc. Journ_., 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. + + * * * * * + + + + +BACTERIA LIFE. + + +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 1/4 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 Muentz, that bacteria cannot exist in the presence of +21/2 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 +1/4 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. + +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 deg. 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. + + * * * * * + + + + +ON THE COMPOSITION OF ELEPHANTS' MILK. + +[Footnote: Read before the American Chemical Society, June 3,1881.] + +By CHAS. A. DOREMUS, M.D., Ph.D. + + +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. + +Through the courtesy of Jas. A. Bailey I was enabled to procure samples +of the milk on several occasions. + +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. + +When born the calf weighed 2131/2 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. + +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. + +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. + +The following represents approximately the daily diet of the mother: + +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. + +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. + +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. + +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. + +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. + +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: + + + No. I. II. III. + April 5, April 9, April 10, + Morning. Noon. Morning. + + Quantity, 19 cc. 36 cc. 72 cc. + Cream, 52-4, vol.% 58 62 + Reaction, Neutral. Slightly alkaline. Slightly acid. + Sp.gr., ---- ---- 1023.7 + + 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 + + +Ten grammes were taken for analysis, and in No. III. duplicates were +made. + +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. + +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. + +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. + +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. + +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. + +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. + +[Footnote 1: "Lehrhuch der Physiologischen Chemie," pp. 423 and 424.] + +Constituents. Woman. Cow. Goat. Ewe. Ass. Mare. + +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 + +Constituents. Buffalo. Camel. Sow. Hippo- Elephant. + potamus. + +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 + +[Footnote 1: Milk Sugar included.] + +It may be remarked that though approaching the composition of cream it +still differs enough to require it to be considered milk. + +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. + +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 deg. C. or 64 deg. F. + +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. + +In size the "Baby" compared equally with other elephants in the same +menagerie, who were known to be four and five years old. + +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. + + * * * * * + + + + +THE CHEMICAL COMPOSITION OF RICE, MAIZE, AND BARLEY. + +By J. STEINER, F.C.S. + + +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. + +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: + + Barley. Maize. Rice. + -------------- ------------- ------------------ + Air Dried at Air Dried at Air Dried at With + Dry. 100 deg. C. Dry. 100 deg. C. Dry. 100 deg. C. Husk. + +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 + +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. + +But on the other hand, barley and maize are richer in albuminous matter +and in ash. The extractive matter, _i. e._, 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). + +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. + + 100 parts of + Potash Lime Magnesia Phosphoric Silica grain contain + acid ash. + +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 " + +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. + +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.--_London +Brewers' Journal._ + + * * * * * + + + + +PETROLEUM OILS. + + +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. + +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. + +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. + +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 _per se_, 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. + +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.--_Fireman's Journal_ + + * * * * * + + + + +COMPOSITION OF THE PETROLEUM OF THE CAUCASUS. + +By MM. P SCHUTZENBERGER and N. TONINE. + + +All portions of this petroleum contain saturated carbides of the formula +C_nH_{2n}, which the authors name paraffenes. At a bright red heat they +yield benzinic carbides, C_nH_{2n-6}, 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. + + * * * * * + + + + +NOTES ON CANANGA OIL OR ILANG-ILANG OIL. + +[Footnote: From the _Archiv der Pharmacie_.] + +By F. A. FLUeCKIGER. + + +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. + +The tree, of which the flowers yield the oil known under the name +"Ilang-ilang" or "Alanguilan," is the _Cananga odorata_, Hook. fil. et +Thomp.,[1] of the order Unonaceae, for which reason it is called also in +many price lists "Oleum Anonae," or "Oleum Unonae" 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 Lucon[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, _Uvaria odorata_." According to Roxburgh,[6] +the plant was in 1797 brought from Sumatra to the Botanical Gardens in +Calcutta. Dunal devoted to the _Ucaria odorata_, or, properly, _Unona +odorata_, 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. + +[Footnote 1: "Flora Indica," i (1855), 130.] + +[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, _New Remedies_, April, 1881, page 98.] + +[Footnote 3: Ray. "Historia Plantarum, Supplementum," tomi i et ii +"Hist. Stirpium Insulae Luzonensis et Philippinarum" a Georgio Josepho +Canello; London, 1704, 83] + +[Footnote 4: "Herbarium Amboinense, Amboinsch Kruidboek," ii. +(Amsterdam, 1750), cap. xix, fol. 195 and tab. 65.] + +[Footnote 5: "Encyclopedie methodique. Botanique," i (1783), 595.] + +[Footnote 6: "Flora Indica," ii. (Serampore, 1832), 661.] + +[Footnote 7: Paris, 1817, p. 108, 105.] + +Lastly, we owe a very handsome figure of the _Cananga odorata_ to the +magnificent "Flora Javae," 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 _Unona odoratissima_, 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 _Uvaria_, from which he would not +separate the Ilang-ilang tree. + +[Footnote 1: Vol. i. (Brussels, 1829), fol. 29, tab ix et xiv. B.] + +[Footnote 2: "Flora de Filipinas," Manila, 1845, 325. _Unona +odoratissima_, 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.] + +[Footnote 3: "Dictionnaire de Botanique."] + +[Illustration: CANAGA ODORATA] + +The notice of Maximowicz,[1] "Ueber den Ursprung des Parfums +Ylang-Ylang," contains only a confirmation of the derivation of the +perfume from Cananga. + +[Footnote 1: Just's "Botanischer Jahresbericht," 1875, 973.] + +_Cananga odorata_ 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 _Cananga odorata_ 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. + +_Cananga odorata_, 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 _Unona_ or _Uvaria_, among +which some equally possess odorous flowers, are now distributed between +those two genera, which are tolerably rich in species. From _Uvaria_ +the _Cananga_ differs in its valvate petals, and from _Unona_ in the +arrangement of the seeds in two rows. + +[Footnote 1: "Genera Plantarum," i, (1864), 24.] + +_Cananga odorata_ 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 _Michelia champaca_, L.,[1] of the +family Magnoliaceae, 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" (_Michelia champaca_) and the "Kenangga wangi" +(_Cananga odorata_)[2] stand in the first rank. + +[Footnote 1: A beautiful figure of this also is given in Blume's "Flora +Javae," iii., Magnoliaceae, tab. I.] + +[Footnote 2: Junghuhn, Java, Leipsic, 1852, 166.] + +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] + +[Footnote 1: _Jahresbericht d. Pharmacie_, by Wiggers and Husemann, +1867, 422.] + +[Footnote 2: _Jahresbericht_, 1868, 166.] + +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 _Michelia champaca_, 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 (L30) 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. + +[Footnote 1: _Archiv der Pharmacie_, ccxiv. (1879), 18.] + +[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).] + +[Footnote 3: 25 grammes of oil from 5 kilogrammes of flowers, according +to Reymann.] + +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 _Cananga odorata_ and _Michelia champaca_, and colored +yellow by means of turmeric. In India unguents of this kind have always +been in use. + +[Footnote 1: _Histoire Naturelle des Drogues Simples_, iii. (1850), +675.] + +The name "Cananga" is met with in Germany as occurring in former times. +An "Oleum destillatum Canangae" 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 Laendern 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 _Cananga odorata_, +the fruit-pulp of which is expressly described by Humph and by Blume as +sweetish. Further an "Oleum Canangae, 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 _Andropogon +laniger_. + +[Footnote 1: Compare Flueckiger, "Pharmakognosic," 2d edit, 1881, p. +152.] + +[Footnote 2: Flueckiger, "Documente zur Geschichte der Pharmacie," Halle +(1876), p 93.] + +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 deg. C.; but the thermometer rose gradually to 290 deg., and at a still +higher temperature decomposition commenced. That the portions passing +over below 290 deg. 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 deg. 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. + +[Footnote 1: _Comptes Rendus_, lxxvi. (1873), 1428, and abstracted in +the _Pharmaceutical Journal_ [3], iv., p. 28; also in _Jahresbericht_, +1873, p. 431.] + +[Footnote 2: Overlooking Peru balsam and Tolu balsam.] + +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. + + * * * * * + + + + +CHIAN TURPENTINE. + + +The following letter has been received by the editors of the _Repertoire +de Pharmacie:_ 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. + +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. + +The turpentine tree (_Pistacia terebinthus_ 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. + +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. + +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. + +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 +(_Pistacia lentiscus_ 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. + +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. + +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., + +DR. STIEPOWICH. + +Chio, Turkey. + + * * * * * + + + + +ON THE CHANGE OF VOLUME WHICH ACCOMPANIES THE GALVANIC DEPOSITION OF A +METAL. + +By M. E. BOUTY. + + +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 _neutral point of temperatures_. + +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 _neutral point +of compression_ 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. + +I have determined, by the help of observations made with ten different +current strengths, the constants of the formulae 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: + + A t + (1) y = ------- + B + t + +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: + + (2) A = - a'i + b'i squared, + +of the same form as the expression E: + + E = - ai + bi squared, + +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. + +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.--_Comptes Rendus._ + + * * * * * + + + + +ANALYSES OF RICE SOILS FROM BURMAH. + +By R. ROMANIS, D.Sc., Chemical Examiner, British Burmah. + + +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. + +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. + +Results of two analyses of soils from Syriam, near Rangoon, are +appended: + + _Soluble in Hydrochloric Acid_. + + 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 + + _Soluble in Sulphuric Acid_. + +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 + + _Residue_. + +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 + +These are alluvial soils from the Delta of the Irrawaddy. + + * * * * * + + + + +DRY AIR REFRIGERATING MACHINE. + + +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! + +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. + +[Illustration: COMPRESSION CYLINDER. SCALE 1/60] + +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. + +[Illustration: Expansion Cylinder. Scale 1/60.92 deg. F. temperature of +entering air. Cooling water entering in at 86 deg. F.] + +[Illustration: Expansion Cylinder. Scale 1/60. 68 deg. F. temperature of +entering air. Cooling water entering in at 65 deg. F. 125 revs. per minute, +or 312 ft. per minute per piston speed.] + +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.-_The Engineer_. + +[Illustration: DRY AIR REFRIGERATING MACHINE] + + * * * * * + + + + +THOMAS'S IMPROVED STEAM WHEEL. + + +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. + +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. + +[Illustration: IMPROVED STEAM-WHEEL.] + +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. + + * * * * * + + + + +THE AMERICAN SOCIETY OF CIVIL ENGINEERS. + +ADDRESS OF THE PRESIDENT, JAMES BICHENO FRANCIS, AT THE THIRTEENTH +ANNUAL CONVENTION OF THE SOCIETY AT MONTREAL, JUNE 15, 1881. + + +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. + +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. + +The membership of the society is now as follows: + + Honorary members........ 11 + Corresponding members... 3 + Members................. 491 + Associates.............. 21 + Juniors................. 57 + Fellows................. 53 + ---- + Total................... 636 + +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. + +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. + +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. + + +WATER POWER. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +[Footnote 1: _Journal of the Franklin Institute_ for September, 1877.] + +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. + +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. + +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. + + +ANCHOR ICE. + +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. + +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. + +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 _regelation_, 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. + +[Footnote 1: Paper clx., in the Transactions of the Society, 1878, vol. +vii., pages 109-168.] + +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. + +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. + + * * * * * + + + + +A PAIR OF COTTAGES. + + +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.--_Building News_. + +[Illustration: SUGGESTIONS IN ARCHITECTURE.--A PAIR OF ENGLISH +COTTAGES.--BY A. CAWSTON.] + + * * * * * + + + + +DELICATE SCIENTIFIC INSTRUMENTS. + +By EDGAR L. LARKIN, New Windsor Observatory, New Windsor, Illinois. + + +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 nebulae, 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.) + +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 _its_ 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, faculae, +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 deg. 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. + +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. + +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. + +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. + +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.) + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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." (_Science_, issue of Jan. 8,1881, p. 12.) It is expected to +reveal great facts concerning the heat of the stars. + +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 deg., 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. + +We cannot note the researches of Edison, Lockyer, or Tyndall, nor of +Crookes, who has seemingly reached the molecules whence the universe is +composed. + +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. + +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.--_Kansas Review_. + + * * * * * + + + + +THE FUTURE DEVELOPMENT OF ELECTRICAL APPLIANCES. + + +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. + +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. + +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: + +We Want to Use Water. We Want to Use Electricity. + +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. + +2. Energy available is 2. Energy available is +amount of water lifted x amount of electricity x difference +difference of level. of potential. + +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. + +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. + +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. + +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: + +ELECTRICAL MAGNITUDES (SOME RATHER APPROXIMATE). + +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 " + +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. + +Current measured by us in some experiments: + + 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 + +In any circuit, _current_ in webers = _electro-motive force_ in volts / +_resistance_ in ohms. + + +RATE OF PRODUCTION OF HEAT, CALCULATED IN THE SHAPE OF HORSE-POWER. + +In the whole of a circuit=_current_ in webers x _electro-motive force_ +in volts / 746. In any part of circuit=_current_ in webers x _difference +of potential_ 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. + +If there are a number of generators of electricity in a circuit, whose +electromotive forces in volts are E_1, E_2, etc., and if there are also +opposing electro-motive forces. F_1, F_2, 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: + + (E_1+E_2+etc.)-(F_1+F_2+etc.) +C = ----------------------------- + R + +[TEX: C = \frac{(E_1+E_2+\text{etc.})-(F_1+F_2+\text{etc.})}{R}] + + C C +P = ---((E_1+E_2+etc.); Q = ---(F_1+F_2+etc.) + 746 746 + +[TEX: \frac{C}{746}(E_1+E_2+\text{etc.});\ Q = +\frac{C}{746}(F_1+F_2+\text{etc.})] + + C squared R +H = ----- . + 746 + +[TEX: H = \frac{C^2 R}{746}.] + +The lifting power of an electro-magnet of given volume is proportional +to the heat generated against resistance in the wire of the magnet. + +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. + +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." + +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: + +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: + + C=(E-F) / R + + P=E(E-F) / (746 R) + + Q=F(E-F) / (746 R) + + H=(E-F)_2 / (746 R) + + Q:H::F:E-F + +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. + +"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. + +"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." + +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. + + * * * * * + + + + +RESEARCHES ON THE RADIANT MATTER OF CROOKES AND THE MECHANICAL THEORY OF +ELECTRICITY. + +By DR. W. F. GINTL, abstracted by DR. VON GERICHTEN. + + +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 _sui generis,_ 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. + + * * * * * + + + + +ECONOMY OF THE ELECTRIC LIGHT. + + +Mr. W. H. Preece writes to the _Journal of Arts_ as follows: + +At the South Kensington Museum, very careful observations have been made +on the relative cost of the two systems, _i. e._, 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. + +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. + +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. + +The first outlay has been as follows: + +Engine and fixing, including shafting and +belting................................ L420 +Dynamo machine......................... 400 +Lamps, apparatus, and conducting wire . 384 + ------ + L1,204 + +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: + + L s. d. +Carbons............................... 18 9 0 +Oil, etc.............................. 4 11 6 +Coal.................................. 11 14 0 +Wages................................. 34 7 6 + ---------- + L69 2 0 + +being at the rate of 3s. 10d. per hour of light. + +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 L426 per annum. + +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 L994. 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-- + + L 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.......... L109 10 + +leaving a handsome balance to the good of L316 10s. as against gas. The +results of the working, both practically and financially, have proved to +be, at South Kensington, a decided success. + +I am indebted to Colonel Festing, R.E., who has charge of the lighting, +for these details. + +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. + +"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 11/2d. 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." + +I am indebted for these facts to Mr. J. N. Shoolbred, under whose +supervision the arrangements were made. + +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 L8 9s. per week, the electric light has been adopted at +an expenditure of L4 14s. per week. + +The erecting shop, 450 feet by 150 feet, formerly dimly lit by gas at a +cost of L22 per week, is now efficiently lit by electricity at half the +cost. + +I am indebted for these facts to Mr. Humphreys, the manager of the +works. + +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. + + * * * * * + + + + +ON THE SPACE PROTECTED BY A LIGHTNING-CONDUCTOR. + +By WILLIAM HENRY PREECE. + +[Footnote: From the _Philosophical Magazine_ for December, 1880.] + + +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., Sec. 3122 _et seq._) showed how the distribution of the forces in any +electric field can be graphically depicted by drawing lines (which he +called _lines of force_) 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 _equipotential surface._ +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 _uniform field._ 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. + +[Illustration: Fig. 1] + +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. + +[Illustration: Fig. 2] + +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. + +[Illustration: Fig. 3] + +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, _e f_, would be +reached; disruptive discharge would take place, with its attendant +thunder and lightning. We can let the line, _e f_, 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. + +[Illustration: Fig. 4] + +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. + +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. + +[Illustration: Fig. 5] + +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. + +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. + +_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 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. + + * * * * * + + + + +PHOTO-ELECTRICITY OF FLUOR-SPAR CRYSTALS. + + +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 deg. to 100 deg. C.). + + * * * * * + + + + +THE AURORA BOREALIS AND TELEGRAPH CABLES. + + +The January and February numbers of the _Elektrotechnische Zeitschrift_ +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 deg. 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 +Leclanche cells. + +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.--_Engineering_. + + * * * * * + + + + +THE PHOTOGRAPHIC IMAGE: WHAT IT IS. + +[Footnote: A communication to the Sheffield Photographic Society in the +_British Journal of Photography_.] + + +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. + +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. + +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_2Cl_2=Ag_2Cl+Cl. +When water is present the water is decomposed. Hydrochloric acid, HCl, +hypochlorous acid, HClO is formed. + +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_2Br_2=Ag_2Br+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. + +The theory regarding these sensitive salts of silver is that, being very +unstable, _i. e._, 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. + +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. + +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. + +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_4. 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. + +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. + +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. + +[Illustration: SECTION OF SENSITIVE PLATE AFTER EXPOSURE AND DURING +DEVELOPMENT. + +d Silver deposit--Image, c Sub-bromide and sub-chloride (gradations of), +b Collodion film--Substratum, a Section of glass plate--Support.] + +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_3 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. + +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. + +THOMAS H. MORTON, M.D. + + * * * * * + + + + +GELATINE TRANSPARENCIES FOR THE LANTERN. + +[Footnote: A communication to the Photographic Society of Ireland.] + + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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.--_Thomas Mayne, T. C., +in British Journal of Photography._ + + * * * * * + + + + +AN INTEGRATING MACHINE. + +[Footnote: Read at a meeting of the Physical Society, Feb. 26.] + + +By C.V. BOYS. + +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. + +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 _ascent_ made by the new curve +in passing from one ordinate to the other is a measure of the area +required. + +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. + +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 _drawn_. 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. + +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. + +[Illustration: AN INTEGRATING MACHINE.] + +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. + +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. + +Of the various curves exhibited which have been drawn by the machine, +the following are of special physical interest. + +Given the inclined straight line y = cx, the machine draws the parabola +y = cx squared / 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. + +Given the curve representing attraction y = 1 / x squared 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. + +Given the logarithmic curve y = e^x, 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. + +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. + +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. + +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, _crosses_ the axis of x, or +a point of inflexion unless A passes a maximum or minimum. + + * * * * * + + + + +UPON A MODIFICATION OF WHEATSTONE'S MICROPHONE AND ITS APPLICABILITY TO +RADIOPHONIC RESEARCHES. + +[Footnote: A paper read before the Philosophical Society of Washington. +D. C., June 11, 1881.] + +By ALEXANDER GRAHAM BELL. + + +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. + +[Footnote 1: Amer. Asso. for Advancement of Science, August 27, 1880.] + +[Footnote 2: _Nature_, vol. xxiii., p. 274.] + +[Footnote 3: Roy. Soc., Mar. 10, 1881.] + +[Illustration: Fig. 1. A B, Carbon Supports. C, Diaphragm.] + +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). + +[Footnote 1: April 21, 1881.] + +[Illustration: Fig. 2. A, Stiff wire. B, Diaphragm. C, Hearing tube. D, +Perforated handle.] + +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. + +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. + +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. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +Sent by mail, postage prepaid, to subscribers in any part of the United +States or Canada. Six dollars a year, sent, prepaid, to any foreign +country. + +All the back numbers of THE SUPPLEMENT, from the commencement, January +1, 1876, can be had. Price, 10 cents each. + +All the back volumes of THE SUPPLEMENT can likewise be supplied. Two +volumes are issued yearly. 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Do not change or edit the +header without written permission. + +Please read the "legal small print," and other information about the +eBook and Project Gutenberg at the bottom of this file. Included is +important information about your specific rights and restrictions in +how the file may be used. You can also find out about how to make a +donation to Project Gutenberg, and how to get involved. + + +**Welcome To The World of Free Plain Vanilla Electronic Texts** + +**eBooks Readable By Both Humans and By Computers, Since 1971** + +*****These eBooks Were Prepared By Thousands of Volunteers!***** + + +Title: Scientific American Supplement, No. 288 + July 9, 1881 + +Author: Various + +Release Date: June, 2005 [EBook #8391] +[Yes, we are more than one year ahead of schedule] +[This file was first posted on July 6, 2003] + +Edition: 10 + +Language: English + +Character set encoding: ISO-Latin-1 + +*** START OF THE PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN NO. 288 *** + + + + +Olaf Voss, Don Kretz, Juliet Sutherland, Charles Franks +and the Online Distributed Proofreading Team. + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 288 + + + + +NEW YORK, JULY 9, 1881 + +Scientific American Supplement. Vol. XI, No. 288. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + + TABLE OF CONTENTS. + +I. ENGINEERING AND MECHANICS--Dry Air Refrigerating Machine. + 5 figures. Plan, elevation, and diagrams of a new English + dry air refrigerator + + Thomas' Improved Steam Wheel. 1 figure + + 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 + +II. 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. + + Detection of Alcohol in Transparent Soaps. By H. JAY + + On the Calorific Power of Fuel, and on Thompson's Calorimeter. + By J.W. THOMAS + + Explosion as an Unknown Fire Hazard. A suggestive review of + the conditions of explosions, with curious examples + + Carbon. Symbol C. Combining weight. 12. By T. A. POOLEY + Second article on elementary chemistry written for brewers + + Manufacture of Soaps and their Production. By W. J. MENZIES + + The Preparation of Perfume Pomades. 1 figure. "Ensoufflage" + apparatus for perfumes + + Organic Matter in Sea Water + + Bacteria Life. Influence of heat and various gases and chemical + compounds on bacteria life + + On the Composition of Elephant's Milk. By Dr. CHAS. A. DOREMUS. + Comparison of elephant's milk with that of ten other mammals + + The Chemical Composition of Rice. Maize, and Barley. By J. STEINER + + Petroleum Oils. Character and properties of the various distillates + of crude petroleum. Fire risks attending the use of the + lighter petroleum oils + + Composition of the Petroleum of the Caucasus. By P. SCHULZENBERGER + and N. TONINE + + Notes on Cananga Oil. or Ilang-Ilang Oil. By F. A. FLÜCKIGER. + 1 figure. Flower and leaf of Cananga odorata + + Chian Turpentine, and the Tree which Produces It. By Dr. + STIEPOWICH. of Chios, Turkey + + On the Change of Volume which Accompanies the Galvanic Deposition + of a Metal. By M. E. BOUTY + + Analysis of the Rice Soils of Burmah. By R. ROMANIC, Chemical + Examiner, British Burmah + +III. 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 + + 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 + + The Future Development of Electrical Appliances. Lecture by + Prof. J. W. PERRY before the London Society of Arts.--Methods + and units of electrical measurements + + Researches on the Radiant Matter of Crookes and the Mechanical + Theory of Electricity. By Dr. W. F. GINTL + + Economy of the Electric Light. W. H. PREECE'S Experiments + Investigations + + On the Space Protected by a Lightning Conductor. By WM. H. + PREECE.--5 figures + + Photo-Electricity of Fluor Spar Crystals + + The Aurora Borealis and Telegraph Cables + + The Photographic Image: What It Is. By T. H. MORTON. + 1 figure.--Section of sensitive plate after exposure and during + development + + Gelatine Transparencies for the Lantern + + An Integrating Machine. By C. V. BOYS.--1 figure + + Upon a Modification of Wheatstone's Microphone and its + Applicability to Radiophonic Researches. + By ALEX. GRAHAM BELL,--2 figures + +IV. ARCHITECTURE.--Suggestions in Architecture, 1 figure.--A + pair of English cottages. By A. CAWSTON + + * * * * * + + + + +ALCOHOL IN NATURE--ITS PRESENCE IN THE EARTH, WATER, AND ATMOSPHERE. + + +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. + +[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.] + +[Illustration: FIG. 1.--FIRST DISTILLATORY APPARATUS.] + +[Illustration: FIG. 2.--SECOND DISTILLATORY APPARATUS.] + +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. + +[Illustration: Fig. 3.--IODOFORM CRYSTALS OBTAINED DIRECTLY (greatly +magnified).] + +[Illustration: FIG. 4,--IODOFORM CRYSTALS OBTAINED WITH RAIN WATER.] + +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. + +[Illustration: FIG. 5.--IODOFORM CRYSTALS OBTAINED WITH SNOW WATER.] + +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.--_La Nature_. + +[Illustration: FIG. 6.--IODOFORM CRYSTALS OBTAINED WITH VEGETABLE +MOULD.] + + * * * * * + + + + +DETECTION OF ALCOHOL IN TRANSPARENT SOAPS. + +By H. JAY. + + +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. + + * * * * * + + + + +ON THE CALORIFIC POWER OF FUEL, AND ON THOMPSON'S CALORIMETER. + +By J.W. THOMAS, F.C.S., F.I.C. + + +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. + +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: + +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. + +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. + +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): + + Composition per cent. + +Carbon...............................88.33 +Hydrogen............................. 5.08 +Oxygen............................... 3.28 +Nitrogen............................. 0.55 +Sulphur.............................. 0.70 +Ash.................................. 1.26 +Water (moisture)..................... 0.80 + ----- + 100.00 + +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. + +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 _total heat units_ 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 _heat unit_ 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 _all_ 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. + +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 _not_ 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: + + Room at The water should be + + 80° F. 70° F. + 72 64 + 67 60 + 60 54 + 55 50 + 50 46 + 42 40 + +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. + +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. + +By paying attention to such details, and following the method +recommended, the apparatus yields very satisfactory results with +bituminous and semi-bituminous coals.--_Chemical News_. + + * * * * * + + + + +EXPLOSION AS AN UNKNOWN FIRE HAZARD. + + +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 _noise_; it grew to comprehend the idea of _force_ +accompanied with violent outburst; it is advancing to a stage in which +it implies _combustion_ 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. + +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 _fire_ 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 _vs_. 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 _proximate_ cause; and if fire cause +explosion, and explosion cause loss, it is a loss by fire as _efficient_ +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." + +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. + +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. + +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. + +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 _rapid_ 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. + +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, _freely open to the air_. If ignited by a flame, however, in +an unconfined place, gun-cotton only burns with a strong blaze, but +if _confined_ where the temperature reaches 340° F., it explodes with +terrific violence. Somewhat similar is the action of nitro-glycerine and +dynamite, which simply _burn_ if ignited in the open air, while the same +substance will _explode_ 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 _so long as the nail will continue +to enter the wood_. + +[Footnote 1: The purest gun-cotton may be regarded as a _cellulose_, +in which three atoms of hydrogen are replaced by three molecules of +peroxide of nitrogen.] + +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. + +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. + +"The germ of the first knowledge of an explosive was probably the +accidental discovery, ages ago, of the deflagrating property of the +natural saltpeter _when in contact with incandescent charcoal_."[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] + +[Footnote 1: Encyclopædia Britannica, new edition, viii, p. 806.] + +[Footnote 2: _Vide_ Abel's Experiments in Gunpowder, as detailed in +Phil. Trans. Eoy. Soc, 1874.--_Vide_ also _Bull. Soc. d'Encouragement_, +Nov., 1880, p. 633, _Sur les Explosives_.] + +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_3) for the carbon of the charcoal, and the +production of carbonic acid gas (CO_2) 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_2 is reached. Considering +that water (H_2O) 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. + +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 _at_ 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 _warm or hot water_, 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 +_sea water_ was poured on them. + +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. + +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. + +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. + +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 +_employee_ 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. + +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. + +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 _hoisted_ up +and then squashed down." _Query:_ 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.--_American Exchange and +Review._ + + * * * * * + + + + +CARBON.--SYMBOL C.--COMBINING WEIGHT 12. + +By T.A. POOLEY, B.Sc., F.C.S. + + +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 _allotropism_, +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. + +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. + +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. + +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. + +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. + +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. + +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. + +_Carbon Dioxide, or Carbonic Acid, Symbol CO_2_.--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. + +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: + + CaCO_3 + 2HCl = CO_2 + H_2O + CaCl_2 + Calcium Hydrochloric Carbonic Water. Calcium +Carbonate. Acid. Acid. Chloride. + +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. + +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. + +_Carbon Monoxide, or Carbonic Oxide. Symbol CO._--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.--_Brewers' +Guardian._ + + * * * * * + + + + +SEYFFERTH'S PYROMETER. + + +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. + +[Illustration: Fig. 1.--Pyrometer with Electric Indicator.] + +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. + +[Illustration: Fig. 2.--Method of Mounting by means of a cone on vacuum +apparatus.] + +[Illustration: Fig. 3.--Mounting by means of a sleeve on vacuum +apparatus.] + +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. + +_Pyrometers filled with Ether._-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. + +_Pyrometers filled with distilled water_ are used for ascertaining +temperatures ranging from 100° to 265° C., 80° to 210° R., or 212° to +510° F. + +_Pyrometers filled with mercury_ are constructed for ascertaining +temperatures from 360° to 750° C. + +[Illustration: Fig. 4.--Mounting on horizontal pipes by thread on the +tube.] + +[Illustration: Fig. 5.--Mounting by means of a clasp in reservoirs.] + + +APPLICATION OF THE PYROMETER IN BONE BLACK FURNACES. + +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. + +The position that the pyrometer should occupy is subordinate to the +construction of the furnace. Fig. 6 shows the type which is most +employed. + +[Illustration: Fig. 6.--The Pyrometer mounted on a bone-black furnace.] + +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. + +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. + + +APPLICATION OF THE APPARATUS TO BRICK FURNACES AND IN THE MANUFACTURE OF +CHEMICAL PRODUCTS. + +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. + +[Illustration: Fig. 7.--The Pyrometer mounted on a brick furnace.] + + * * * * * + + + + +MANUFACTURERS' SOAPS AND THEIR PRODUCTION. + +By W. J. MENZIES. + + +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. + +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. + +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. + +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 +_alkaline_ 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. + +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. + +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. + +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. + +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.--_Textile Manufacturer._ + + * * * * * + + + + +THE PREPARATION OF PERFUME POMADES. + + +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] + +[Footnote 1: Our illustration has been taken from C. Hofmann, +"Chemisch-technisches Universal-Receptbuch," 8vo, Berlin, 1879, p. 207.] + +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.--_New Remedies._ + +[Illustration: "ENSOUFFLAGE" APPARATUS FOR PERFUMES.] + + * * * * * + + + + +ORGANIC MATTER IN SEA-WATER. + + +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 (_Chem. Soc. Journ_., 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. + + * * * * * + + + + +BACTERIA LIFE. + + +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. + +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. + + * * * * * + + + + +ON THE COMPOSITION OF ELEPHANTS' MILK. + +[Footnote: Read before the American Chemical Society, June 3,1881.] + +By CHAS. A. DOREMUS, M.D., Ph.D. + + +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. + +Through the courtesy of Jas. A. Bailey I was enabled to procure samples +of the milk on several occasions. + +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. + +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. + +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. + +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. + +The following represents approximately the daily diet of the mother: + +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. + +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. + +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. + +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. + +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. + +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: + + + No. I. II. III. + April 5, April 9, April 10, + Morning. Noon. Morning. + + Quantity, 19 cc. 36 cc. 72 cc. + Cream, 52-4, vol.% 58 62 + Reaction, Neutral. Slightly alkaline. Slightly acid. + Sp.gr., ---- ---- 1023.7 + + 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 + + +Ten grammes were taken for analysis, and in No. III. duplicates were +made. + +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. + +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. + +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. + +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. + +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. + +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. + +[Footnote 1: "Lehrhuch der Physiologischen Chemie," pp. 423 and 424.] + +Constituents. Woman. Cow. Goat. Ewe. Ass. Mare. + +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 + +Constituents. Buffalo. Camel. Sow. Hippo- Elephant. + potamus. + +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 + +[Footnote 1: Milk Sugar included.] + +It may be remarked that though approaching the composition of cream it +still differs enough to require it to be considered milk. + +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. + +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. + +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. + +In size the "Baby" compared equally with other elephants in the same +menagerie, who were known to be four and five years old. + +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. + + * * * * * + + + + +THE CHEMICAL COMPOSITION OF RICE, MAIZE, AND BARLEY. + +By J. STEINER, F.C.S. + + +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. + +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: + + Barley. Maize. Rice. + -------------- ------------- ------------------ + Air Dried at Air Dried at Air Dried at With + Dry. 100° C. Dry. 100° C. Dry. 100° C. Husk. + +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 + +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. + +But on the other hand, barley and maize are richer in albuminous matter +and in ash. The extractive matter, _i. e._, 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). + +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. + + 100 parts of + Potash Lime Magnesia Phosphoric Silica grain contain + acid ash. + +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 " + +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. + +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.--_London +Brewers' Journal._ + + * * * * * + + + + +PETROLEUM OILS. + + +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. + +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. + +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. + +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 _per se_, 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. + +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.--_Fireman's Journal_ + + * * * * * + + + + +COMPOSITION OF THE PETROLEUM OF THE CAUCASUS. + +By MM. P SCHUTZENBERGER and N. TONINE. + + +All portions of this petroleum contain saturated carbides of the formula +C_nH_{2n}, which the authors name paraffenes. At a bright red heat they +yield benzinic carbides, C_nH_{2n-6}, 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. + + * * * * * + + + + +NOTES ON CANANGA OIL OR ILANG-ILANG OIL. + +[Footnote: From the _Archiv der Pharmacie_.] + +By F. A. FLÜCKIGER. + + +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. + +The tree, of which the flowers yield the oil known under the name +"Ilang-ilang" or "Alanguilan," is the _Cananga odorata_, 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, _Uvaria odorata_." According to Roxburgh,[6] +the plant was in 1797 brought from Sumatra to the Botanical Gardens in +Calcutta. Dunal devoted to the _Ucaria odorata_, or, properly, _Unona +odorata_, 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. + +[Footnote 1: "Flora Indica," i (1855), 130.] + +[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, _New Remedies_, April, 1881, page 98.] + +[Footnote 3: Ray. "Historia Plantarum, Supplementum," tomi i et ii +"Hist. Stirpium Insulæ Luzonensis et Philippinarum" a Georgio Josepho +Canello; London, 1704, 83] + +[Footnote 4: "Herbarium Amboinense, Amboinsch Kruidboek," ii. +(Amsterdam, 1750), cap. xix, fol. 195 and tab. 65.] + +[Footnote 5: "Encyclopédie méthodique. Botanique," i (1783), 595.] + +[Footnote 6: "Flora Indica," ii. (Serampore, 1832), 661.] + +[Footnote 7: Paris, 1817, p. 108, 105.] + +Lastly, we owe a very handsome figure of the _Cananga odorata_ 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 _Unona odoratissima_, 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 _Uvaria_, from which he would not +separate the Ilang-ilang tree. + +[Footnote 1: Vol. i. (Brussels, 1829), fol. 29, tab ix et xiv. B.] + +[Footnote 2: "Flora de Filipinas," Manila, 1845, 325. _Unona +odoratissima_, 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.] + +[Footnote 3: "Dictionnaire de Botanique."] + +[Illustration: CANAGA ODORATA] + +The notice of Maximowicz,[1] "Ueber den Ursprung des Parfums +Ylang-Ylang," contains only a confirmation of the derivation of the +perfume from Cananga. + +[Footnote 1: Just's "Botanischer Jahresbericht," 1875, 973.] + +_Cananga odorata_ 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 _Cananga odorata_ 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. + +_Cananga odorata_, 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 _Unona_ or _Uvaria_, among +which some equally possess odorous flowers, are now distributed between +those two genera, which are tolerably rich in species. From _Uvaria_ +the _Cananga_ differs in its valvate petals, and from _Unona_ in the +arrangement of the seeds in two rows. + +[Footnote 1: "Genera Plantarum," i, (1864), 24.] + +_Cananga odorata_ 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 _Michelia champaca_, 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" (_Michelia champaca_) and the "Kenangga wangi" +(_Cananga odorata_)[2] stand in the first rank. + +[Footnote 1: A beautiful figure of this also is given in Blume's "Flora +Javæ," iii., Magnoliaceæ, tab. I.] + +[Footnote 2: Junghuhn, Java, Leipsic, 1852, 166.] + +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] + +[Footnote 1: _Jahresbericht d. Pharmacie_, by Wiggers and Husemann, +1867, 422.] + +[Footnote 2: _Jahresbericht_, 1868, 166.] + +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 _Michelia champaca_, 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. + +[Footnote 1: _Archiv der Pharmacie_, ccxiv. (1879), 18.] + +[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).] + +[Footnote 3: 25 grammes of oil from 5 kilogrammes of flowers, according +to Reymann.] + +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 _Cananga odorata_ and _Michelia champaca_, and colored +yellow by means of turmeric. In India unguents of this kind have always +been in use. + +[Footnote 1: _Histoire Naturelle des Drogues Simples_, iii. (1850), +675.] + +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 _Cananga odorata_, +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 _Andropogon +laniger_. + +[Footnote 1: Compare Flückiger, "Pharmakognosic," 2d edit, 1881, p. +152.] + +[Footnote 2: Flückiger, "Documente zur Geschichte der Pharmacie," Halle +(1876), p 93.] + +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. + +[Footnote 1: _Comptes Rendus_, lxxvi. (1873), 1428, and abstracted in +the _Pharmaceutical Journal_ [3], iv., p. 28; also in _Jahresbericht_, +1873, p. 431.] + +[Footnote 2: Overlooking Peru balsam and Tolu balsam.] + +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. + + * * * * * + + + + +CHIAN TURPENTINE. + + +The following letter has been received by the editors of the _Repertoire +de Pharmacie:_ 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. + +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. + +The turpentine tree (_Pistacia terebinthus_ 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. + +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. + +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. + +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 +(_Pistacia lentiscus_ 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. + +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. + +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., + +DR. STIEPOWICH. + +Chio, Turkey. + + * * * * * + + + + +ON THE CHANGE OF VOLUME WHICH ACCOMPANIES THE GALVANIC DEPOSITION OF A +METAL. + +By M. E. BOUTY. + + +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 _neutral point of temperatures_. + +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 _neutral point +of compression_ 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. + +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: + + A t + (1) y = ------- + B + t + +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: + + (2) A = - a'i + b'i², + +of the same form as the expression E: + + E = - ai + bi², + +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. + +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.--_Comptes Rendus._ + + * * * * * + + + + +ANALYSES OF RICE SOILS FROM BURMAH. + +By R. ROMANIS, D.Sc., Chemical Examiner, British Burmah. + + +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. + +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. + +Results of two analyses of soils from Syriam, near Rangoon, are +appended: + + _Soluble in Hydrochloric Acid_. + + 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 + + _Soluble in Sulphuric Acid_. + +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 + + _Residue_. + +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 + +These are alluvial soils from the Delta of the Irrawaddy. + + * * * * * + + + + +DRY AIR REFRIGERATING MACHINE. + + +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! + +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. + +[Illustration: COMPRESSION CYLINDER. SCALE 1/60] + +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. + +[Illustration: Expansion Cylinder. Scale 1/60.92° F. temperature of +entering air. Cooling water entering in at 86° F.] + +[Illustration: Expansion Cylinder. Scale 1/60. 68° F. temperature of +entering air. Cooling water entering in at 65° F. 125 revs. per minute, +or 312 ft. per minute per piston speed.] + +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.-_The Engineer_. + +[Illustration: DRY AIR REFRIGERATING MACHINE] + + * * * * * + + + + +THOMAS'S IMPROVED STEAM WHEEL. + + +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. + +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. + +[Illustration: IMPROVED STEAM-WHEEL.] + +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. + + * * * * * + + + + +THE AMERICAN SOCIETY OF CIVIL ENGINEERS. + +ADDRESS OF THE PRESIDENT, JAMES BICHENO FRANCIS, AT THE THIRTEENTH +ANNUAL CONVENTION OF THE SOCIETY AT MONTREAL, JUNE 15, 1881. + + +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. + +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. + +The membership of the society is now as follows: + + Honorary members........ 11 + Corresponding members... 3 + Members................. 491 + Associates.............. 21 + Juniors................. 57 + Fellows................. 53 + ---- + Total................... 636 + +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. + +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. + +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. + + +WATER POWER. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +[Footnote 1: _Journal of the Franklin Institute_ for September, 1877.] + +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. + +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. + +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. + + +ANCHOR ICE. + +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. + +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. + +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 _regelation_, 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. + +[Footnote 1: Paper clx., in the Transactions of the Society, 1878, vol. +vii., pages 109-168.] + +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. + +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. + + * * * * * + + + + +A PAIR OF COTTAGES. + + +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.--_Building News_. + +[Illustration: SUGGESTIONS IN ARCHITECTURE.--A PAIR OF ENGLISH +COTTAGES.--BY A. CAWSTON.] + + * * * * * + + + + +DELICATE SCIENTIFIC INSTRUMENTS. + +By EDGAR L. LARKIN, New Windsor Observatory, New Windsor, Illinois. + + +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.) + +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 _its_ 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. + +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. + +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. + +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. + +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.) + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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." (_Science_, issue of Jan. 8,1881, p. 12.) It is expected to +reveal great facts concerning the heat of the stars. + +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. + +We cannot note the researches of Edison, Lockyer, or Tyndall, nor of +Crookes, who has seemingly reached the molecules whence the universe is +composed. + +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. + +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.--_Kansas Review_. + + * * * * * + + + + +THE FUTURE DEVELOPMENT OF ELECTRICAL APPLIANCES. + + +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. + +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. + +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: + +We Want to Use Water. We Want to Use Electricity. + +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. + +2. Energy available is 2. Energy available is +amount of water lifted x amount of electricity x difference +difference of level. of potential. + +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. + +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. + +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. + +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: + +ELECTRICAL MAGNITUDES (SOME RATHER APPROXIMATE). + +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 " + +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. + +Current measured by us in some experiments: + + 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 + +In any circuit, _current_ in webers = _electro-motive force_ in volts / +_resistance_ in ohms. + + +RATE OF PRODUCTION OF HEAT, CALCULATED IN THE SHAPE OF HORSE-POWER. + +In the whole of a circuit=_current_ in webers x _electro-motive force_ +in volts / 746. In any part of circuit=_current_ in webers x _difference +of potential_ 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. + +If there are a number of generators of electricity in a circuit, whose +electromotive forces in volts are E_1, E_2, etc., and if there are also +opposing electro-motive forces. F_1, F_2, 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: + + (E_1+E_2+etc.)-(F_1+F_2+etc.) +C = ----------------------------- + R + +[TEX: C = \frac{(E_1+E_2+\text{etc.})-(F_1+F_2+\text{etc.})}{R}] + + C C +P = ---((E_1+E_2+etc.); Q = ---(F_1+F_2+etc.) + 746 746 + +[TEX: \frac{C}{746}(E_1+E_2+\text{etc.});\ Q = +\frac{C}{746}(F_1+F_2+\text{etc.})] + + C² R +H = ----- . + 746 + +[TEX: H = \frac{C^2 R}{746}.] + +The lifting power of an electro-magnet of given volume is proportional +to the heat generated against resistance in the wire of the magnet. + +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. + +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." + +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: + +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: + + C=(E-F) / R + + P=E(E-F) / (746 R) + + Q=F(E-F) / (746 R) + + H=(E-F)_2 / (746 R) + + Q:H::F:E-F + +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. + +"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. + +"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." + +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. + + * * * * * + + + + +RESEARCHES ON THE RADIANT MATTER OF CROOKES AND THE MECHANICAL THEORY OF +ELECTRICITY. + +By DR. W. F. GINTL, abstracted by DR. VON GERICHTEN. + + +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 _sui generis,_ 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. + + * * * * * + + + + +ECONOMY OF THE ELECTRIC LIGHT. + + +Mr. W. H. Preece writes to the _Journal of Arts_ as follows: + +At the South Kensington Museum, very careful observations have been made +on the relative cost of the two systems, _i. e._, 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. + +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. + +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. + +The first outlay has been as follows: + +Engine and fixing, including shafting and +belting................................ £420 +Dynamo machine......................... 400 +Lamps, apparatus, and conducting wire . 384 + ------ + £1,204 + +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: + + £ s. d. +Carbons............................... 18 9 0 +Oil, etc.............................. 4 11 6 +Coal.................................. 11 14 0 +Wages................................. 34 7 6 + ---------- + £69 2 0 + +being at the rate of 3s. 10d. per hour of light. + +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. + +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-- + + £ 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 + +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. + +I am indebted to Colonel Festing, R.E., who has charge of the lighting, +for these details. + +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. + +"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." + +I am indebted for these facts to Mr. J. N. Shoolbred, under whose +supervision the arrangements were made. + +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. + +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. + +I am indebted for these facts to Mr. Humphreys, the manager of the +works. + +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. + + * * * * * + + + + +ON THE SPACE PROTECTED BY A LIGHTNING-CONDUCTOR. + +By WILLIAM HENRY PREECE. + +[Footnote: From the _Philosophical Magazine_ for December, 1880.] + + +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 _et seq._) showed how the distribution of the forces in any +electric field can be graphically depicted by drawing lines (which he +called _lines of force_) 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 _equipotential surface._ +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 _uniform field._ 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. + +[Illustration: Fig. 1] + +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. + +[Illustration: Fig. 2] + +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. + +[Illustration: Fig. 3] + +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, _e f_, would be +reached; disruptive discharge would take place, with its attendant +thunder and lightning. We can let the line, _e f_, 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. + +[Illustration: Fig. 4] + +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. + +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. + +[Illustration: Fig. 5] + +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. + +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. + +_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 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. + + * * * * * + + + + +PHOTO-ELECTRICITY OF FLUOR-SPAR CRYSTALS. + + +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.). + + * * * * * + + + + +THE AURORA BOREALIS AND TELEGRAPH CABLES. + + +The January and February numbers of the _Elektrotechnische Zeitschrift_ +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. + +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.--_Engineering_. + + * * * * * + + + + +THE PHOTOGRAPHIC IMAGE: WHAT IT IS. + +[Footnote: A communication to the Sheffield Photographic Society in the +_British Journal of Photography_.] + + +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. + +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. + +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_2Cl_2=Ag_2Cl+Cl. +When water is present the water is decomposed. Hydrochloric acid, HCl, +hypochlorous acid, HClO is formed. + +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_2Br_2=Ag_2Br+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. + +The theory regarding these sensitive salts of silver is that, being very +unstable, _i. e._, 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. + +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. + +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. + +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_4. 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. + +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. + +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. + +[Illustration: SECTION OF SENSITIVE PLATE AFTER EXPOSURE AND DURING +DEVELOPMENT. + +d Silver deposit--Image, c Sub-bromide and sub-chloride (gradations of), +b Collodion film--Substratum, a Section of glass plate--Support.] + +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_3 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. + +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. + +THOMAS H. MORTON, M.D. + + * * * * * + + + + +GELATINE TRANSPARENCIES FOR THE LANTERN. + +[Footnote: A communication to the Photographic Society of Ireland.] + + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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. + +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.--_Thomas Mayne, T. C., +in British Journal of Photography._ + + * * * * * + + + + +AN INTEGRATING MACHINE. + +[Footnote: Read at a meeting of the Physical Society, Feb. 26.] + + +By C.V. BOYS. + +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. + +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 _ascent_ made by the new curve +in passing from one ordinate to the other is a measure of the area +required. + +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. + +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 _drawn_. 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. + +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. + +[Illustration: AN INTEGRATING MACHINE.] + +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. + +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. + +Of the various curves exhibited which have been drawn by the machine, +the following are of special physical interest. + +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. + +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. + +Given the logarithmic curve y = e^x, 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. + +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. + +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. + +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, _crosses_ the axis of x, or +a point of inflexion unless A passes a maximum or minimum. + + * * * * * + + + + +UPON A MODIFICATION OF WHEATSTONE'S MICROPHONE AND ITS APPLICABILITY TO +RADIOPHONIC RESEARCHES. + +[Footnote: A paper read before the Philosophical Society of Washington. +D. C., June 11, 1881.] + +By ALEXANDER GRAHAM BELL. + + +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. + +[Footnote 1: Amer. Asso. for Advancement of Science, August 27, 1880.] + +[Footnote 2: _Nature_, vol. xxiii., p. 274.] + +[Footnote 3: Roy. Soc., Mar. 10, 1881.] + +[Illustration: Fig. 1. A B, Carbon Supports. C, Diaphragm.] + +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). + +[Footnote 1: April 21, 1881.] + +[Illustration: Fig. 2. A, Stiff wire. B, Diaphragm. C, Hearing tube. D, +Perforated handle.] + +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. + +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. + +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. + + * * * * * + +A catalogue, containing brief notices of many important scientific +papers heretofore published in the SUPPLEMENT, may be had gratis at this +office. + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +Sent by mail, postage prepaid, to subscribers in any part of the United +States or Canada. Six dollars a year, sent, prepaid, to any foreign +country. + +All the back numbers of THE SUPPLEMENT, from the commencement, January +1, 1876, can be had. Price, 10 cents each. + +All the back volumes of THE SUPPLEMENT can likewise be supplied. Two +volumes are issued yearly. 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