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+The Project Gutenberg EBook of Scientific American Supplement, No. 288,
+by Various
+#4 in our series
+
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+
+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.
+
+       *       *       *       *       *
+
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+The Project Gutenberg EBook of Scientific American Supplement, No. 288,
+by Various
+#4 in our series
+
+Copyright laws are changing all over the world. Be sure to check the
+copyright laws for your country before downloading or redistributing
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+*****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.
+
+       *       *       *       *       *
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