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diff --git a/old/7028610.txt b/old/7028610.txt new file mode 100644 index 0000000..b1b8037 --- /dev/null +++ b/old/7028610.txt @@ -0,0 +1,3824 @@ +The Project Gutenberg EBook of Scientific American Supplement, No. 286, +by Various +#2 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 +this or any other Project Gutenberg eBook. + +This header should be the first thing seen when viewing this Project +Gutenberg file. Please do not remove it. Do not change or edit the +header without written permission. + +Please read the "legal small print," and other information about the +eBook and Project Gutenberg at the bottom of this file. Included is +important information about your specific rights and restrictions in +how the file may be used. You can also find out about how to make a +donation to Project Gutenberg, and how to get involved. + + +**Welcome To The World of Free Plain Vanilla Electronic Texts** + +**eBooks Readable By Both Humans and By Computers, Since 1971** + +*****These eBooks Were Prepared By Thousands of Volunteers!***** + + +Title: Scientific American Supplement, No. 286 + June 25, 1881 + +Author: Various + +Release Date: June, 2005 [EBook #8297] +[Yes, we are more than one year ahead of schedule] +[This file was first posted on July 4, 2003] + +Edition: 10 + +Language: English + +Character set encoding: ASCII + +*** START OF THE PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN NO. 286 *** + + + + +Produced by Olaf Voss, Don Kretz, Juliet Sutherland, +Charles Franks and the Online Distributed Proofreading Team. + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 286 + + + + +NEW YORK, JUNE 25, 1881 + +Scientific American Supplement. Vol. XI, No. 286. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + + TABLE OF CONTENTS. + +I. ENGINEERING AND MECHANICS.--One Thousand Horse Power Corliss Engine. + 5 figures, to scale, illustrating the construction of the new one + thousand horse power Corliss engine, by Hitch, Hargreaves & Co. + + Opening of the New Workshop of the Stevens Institute of Technology. + Speech of Prof. R.W. Raymond, speech of Mr. Horatio Allen. + + Light Steam Engine for Aeronautical Purposes. Constructed for Capt. + Mojoisky, of the Russian Navy. + + Complete Prevention of Incrustation in Boilers. Arrangement for + purifying boiler water with lime and carbonate of soda.--The + purification of the water.--Examination of the purified + water.--Results of water purification. + + Eddystone Lighthouse. Progress of the work. + + Rolling Mill for Making Corrugated Iron. 1 figure. The new mill of + Schultz, Knaudt & Co., of Essen, Germany. + + Railway Turntable in the Time of Louis XIV. 1 figure. Pleasure car. + Railway and turntable at Mary-le-Roy Chateau, France, in 1714. + + New Signal Wire Compensator. Communication from A. Lyle, describing + compensators in use on the Nizam State Railway, East India. + + Tangye's Hydraulic Hoist. 2 figures. + + Power Loom for Delicate Fabrics. 1 figure. + + How Veneering is Made. + +II. TECHNOLOGY AND CHEMISTRY.--The Constituent Parts of Leather. The + composition of different leathers exhibited at the Paris + Exhibition.--Amount of leather produced by different tonnages of 100 + pounds of hides.--Percentage of tannin absorbed under different + methods of tanning.--Amounts of gelatine and tannin in leather of + different tonnages, etc. + + Progress in American Pottery. + + Photographic Notes.--Mr. Waruerke's New Discovery.--Method of + converting negatives directly into positives.--Experiments of Capt. + Bing on the sensitiveness of coal oil--Bitumen plates.--Method of + topographic engraving. By Commandant DE LA NOE.--Succinate of Iron + Developer.--Method of making friable hydro-cellulose. + + Photo-Tracings in Black and Color. + + Dyeing Reds with Artificial Alizarin. By M. MAURICE PRUD'HOMME. + +III. ELECTRICITY, PHYSICAL SCIENCE, ETC.--On Faure's Secondary Battery. + + Physical Science in Our Common Schools.--An exceptionally strong + argument for the teaching of physical science by the experimental + method in elementary schools, with an outline of the method and the + results of such teaching. + + On the Law of Avogadro and Ampere. By E. VOGEL. + +IV. GEOGRAPHY, GEOLOGY, ETC.--Petroleum and Coal in Venezuela. + + Geographical Society of the Pacific. + + The Behring's Straits Currents.--Proofs of their existence. + + Experimental Geology.--Artificial production of calcareous pisolites + and oolites.--On crystals of anhydrous lime.--4 figures. + +V. NATURAL HISTORY, ETC.--Coccidae. By Dr. H. BEHR.--An important paper + read before the California Academy of Sciences.--The marvelous + fecundity of scale bugs.--Their uses.--Their ravages.--Methods of + destroying them. + + Agricultural Items. + + Timber Trees. + + Blood Rains. + +VI. MEDICINE AND HYGIENE.--Medical Uses of Figs. + + Topical Medication in Phthisis. + +VII. ARCHITECTURE, ETC.--Suggestions in Architecture.--Large + illustration.--The New High School for Girls, Oxford, England. + + * * * * * + + + + +PETROLEUM AND COAL IN VENEZUELA. + + +MR. E. H. PLUMACHER, U. S. Consul at Maracaibo, sends to the State +Department the following information touching the wealth of coal and +petroleum probable in Venezuela: + +The asphalt mines and petroleum fountains are most abundant in that part +of the country lying between the River Zulia and the River Catatumbo, +and the Cordilleras. The wonderful sand-bank is about seven kilometers +from the confluence of the Rivers Tara and Sardinarte. It is ten meters +high and thirty meters long. On its surface can be seen several round +holes, out of which rises the petroleum and water with a noise like that +made by steam vessels when blowing off steam, and above there ascends a +column of vapor. There is a dense forest around this sand-bank, and the +place has been called "El Inferno." Dr. Edward McGregor visited the +sand-bank, and reported to the Government that by experiment he had +ascertained that one of the fountains spurted petroleum and water at the +rate of 240 gallons per hour. Mr. Plumacher says that the petroleum is +of very good quality, its density being that which the British market +requires in petroleum imported from the United States. The river, up to +the junction of the Tara and Sardinarte, is navigable during the entire +year for flat-bottomed craft of forty or fifty tons. + +Mr. Plumacher has been unable to discover that there are any deposits +of asphalt or petroleum in the upper part of the Department of Colon, +beyond the Zulia, but he has been told that the valleys of Cucuta and +the territories of the State of Tachira abound in coal mines. There are +coal mines near San Antonia, in a ravine called "La Carbonera," and +these supply coal for the smiths' forges in that place. Coal and asphalt +are also found in large quantities in the Department of Sucre. Mr. +Plumacher has seen, while residing in the State of Zulia, but one true +specimen of "lignite," which was given to him by a rich land-owner, +who is a Spanish subject. In the section where it was found there are +several fountains of a peculiar substance. It is a black liquid, of +little density, strongly impregnated with carbonic acid which it +transmits to the water which invariably accompanies it. Deposits of this +substance are found at the foot of the spurs of the Cordilleras, and are +believed to indicate the presence of great deposits of anthracite. + +There are many petroleum wells of inferior quality between Escuque and +Bettijoque, in the town of Columbia. Laborers gather the petroleum in +handkerchiefs. After these become saturated, the oil is pressed out by +wringing. It is burned in the houses of the poor. The people thought, in +1824, that it was a substance unknown elsewhere, and they called it +the "oil of Columbia." At that time they hoped to establish a valuable +industry by working it, and they sent to England, France, and this +country samples which attracted much attention. But in those days no +method of refining the crude oil had been discovered, and therefore +these efforts to introduce petroleum to the world soon failed. + +The plains of Ceniza abound in asphalt and petroleum. There is a large +lake of these substances about twelve kilometers east of St. Timoteo, +and from it some asphalt is taken to Maracaibo. Many deposits of asphalt +are found between these plains and the River Mene. The largest is that +of Cienega de Mene, which is shallow. At the bottom lies a compact +bed of asphalt, which is not used at present, except for painting +the bottoms of vessels to keep off the barnacles. There are wells of +petroleum in the State of Falcon. + +Mr. Plumacher says that all the samples of coal submitted to him in +Venezuela for examination, with the exception of the "lignite" before +mentioned, were, in his opinion, asphalt in various degrees of +condensation. The sample which came from Tule he ranks with the coals +of the best quality. He believes that the innumerable fountains and +deposits of petroleum, bitumen, and asphalt that are apparent on the +surface of the region around Lake Maracaibo are proof of the existence +below of immense deposits of coal. These deposits have not been +uncovered because the territory remains for the most part as wild as it +was at the conquest. + + * * * * * + + + + +ONE THOUSAND HORSE-POWER CORLISS ENGINE. + + +[Illustration: FIG. 1. + +DIA. OF CYLINDER = 40'' +STROKE = 10 ft. +REVS = 41 +SCALE OF DIAGRAMS 40 LBS = 1 INCH + +FIG. 2.] + +We illustrate one of the largest Corliss engines ever constructed. It is +of the single cylinder, horizontal, condensing type, with one cylinder +40 inches diameter, and 10 feet stroke, and makes forty-five revolutions +per minute, corresponding to a piston speed of 900 feet per minute. At +mid stroke the velocity of the piston is 1,402 feet per minute nearly, +and its energy in foot pounds amounts to about 8.6 times its weight. +The cylinder is steam jacketed on the body and ends, and is fitted with +Corliss valves and Inglis & Spencer's automatic Corliss valve expansion +gear. Referring to the general drawing of the engine, it will be seen +that the cylinder is bolted directly to the end of the massive cast iron +frame, and the piston coupled direct to the crank by the steel piston +rod and crosshead and the connecting rod. The connecting rod is 28 +feet long center to center, and 12 inches diameter at the middle. The +crankshaft is made of forged Bolton steel, and is 21 inches diameter at +the part where the fly-wheel is carried. The fly driving wheel is 35 +feet in diameter, and grooved for twenty-seven ropes, which transmit the +power direct to the various line shafts in the mill. The rope grooves +are made on Hick, Hargreaves & Co.'s standard pattern of deep groove, +and the wheel, which is built up, is constructed on their improved plan +with separate arms and boss, and twelve segments in the rim with joints +planed to the true angle by a special machine designed and made by +themselves. The weight of the fly-wheel is about 60 tons. The condensing +apparatus is arranged below, so that there is complete drainage from the +cylinder to the condenser. The air pump, which is 36 inches diameter and +2 feet 6 inches stroke, is a vertical pump worked by wrought iron +plate levers and two side links, shown by dotted lines, from the main +crosshead. The engine is fenced off by neat railing, and a platform with +access from one side is fitted round the top of the cylinder for getting +conveniently to the valve spindles and lubricators. The above engraving, +which is a side elevation of the cylinder, shows the valve gear +complete. There are two central disk plates worked by separate +eccentrics, which give separate motion to the steam and exhaust valves. +The eccentrics are mounted on a small cross shaft, which is driven by a +line shaft and gear wheels. The piston rod passes out at the back end of +the cylinder and is carried by a shoe slide and guide bar, as shown more +fully in the detailed sectional elevation through the cylinder, showing +also the covers and jackets in section. The cylinder, made in four +pieces, is built up on Mr. W. Inglis's patent arrangement, with separate +liner and steam jacket casing and separate end valve chambers. This +arrangement simplifies the castings and secures good and sound ones. The +liner has face joints, which are carefully scraped up to bed truly to +the end valve chambers. The crosshead slides are each 3 feet 3 inches +long and I foot 3 inches wide. The engine was started last year, and +has worked beautifully from the first, without heating of bearings or +trouble of any kind, and it gives most uniform and steady turning. It is +worked now at forty-one revolutions per minute, or only 820 feet piston +speed, but will be worked regularly at the intended 900 feet piston +speed per minute when the spinning machinery is adapted for the increase +which the four extra revolutions per minute of the engine will give; the +load driven is over 1,000 horsepower, the steam pressure being 50 lb. +to 55 lb., which, however, will be increased when the existing boilers, +which are old, come to be replaced by new. Indicator diagrams from the +engines are given on page 309. The engine is very economical in steam +consumption, but no special trials or tests have been made with it. An +exactly similar engine, but of smaller size, with a cylinder 30 inches +diameter and 8 feet stroke, working at forty-five revolutions per +minute, made by Messrs. Hick, Hargreaves & Co. for Sir Titus Salt, +Sons & Co.'s mill at Saltaire, was tested about two years ago by Mr. +Fletcher, chief engineer of the Manchester Steam Users' Association, and +the results which are given below pretty fairly represent the results +obtained from this class of engine. Messrs. Hick, Hargreaves & Co. are +now constructing a single engine of the same type for 1,800 indicated +horse-power for a cotton mill at Bolton; and they have an order for a +pair of horizontal compound Corliss engines intended to indicate 3,000 +horse-power. These engines will be the largest cotton mill engines in +the world.--_The Engineer_. + +[Illustration: 1000 HORSE POWER CORLISS ENGINE.--BY HICK. HARGREAVES & +CO.] + +_Result of Trials with Saltaire Horizontal Engine on February 14th and +15th, 1878. Trials made by Mr. L.E. Fletcher, Chief Engineer Steam +Users' Association, Manchester._ + +Engine single-cylinder, with Corliss valves. Inglis and Spencer's valve +gear. Diameter of cylinder. 30in.; stroke, 8ft.; 45 revolutions per +minute. + +No. of trials +Total 1.H.P. +[MB] Mean boiler pressure. +[MP] Mean pressure on piston at beginning of stroke. +[ML] Mean loss between boiler pressure and cylinder. +[MA] Mean average pressure on piston. +[W] Water Per I.H.P. per hour. +[C] Coal per I.H.P. per hour. + +No. of trials Total MB MP ML MA W C + I.H.P. lb lb lb lb lb lb +Trial No. 1. 301.89 46.6 44.11 2.53 21.23 18.373 2.699 +Trial No. 2. 309.66 47.63 44.45 3.18 21.67 17.599 2.561 +Means. 305.775 47.115 44.28 2.855 21.45 17.986 2.630 + +[Illustration: 1000 HORSE POWER CORLISS ENGINE.--BY HICK, HARGREAVES +& CO.] [Illustration: 1000 HORSE POWER CORLISS ENGINE.--BY HICK, +HARGREAVES & CO.] + + * * * * * + + + + +OPENING OF THE NEW WORKSHOP OF THE STEVENS INSTITUTE OF TECHNOLOGY. + + +In our SUPPLEMENT No. 283 we gave reports of some of the addresses of +the distinguished speakers, and we now present the remarks of Prof. +Raymond and Horatio Allen, Esq.: + + +SPEECH OF PROF. R. W. RAYMOND. + +A few years ago, at one of the meetings of our Society of Civil +Engineers we spent a day or so in discussing the proper mode of +educating young men so as to fit them for that profession. It is a +question that is reopened for us as soon as we arrive at the age when +we begin to consider what career to lay out for our sons. When we were +young, the only question with parents in the better walks of life was, +whether their sons should be lawyers, physicians, or ministers. Anything +less than a professional career was looked upon as a loss of caste, a +lowering in the social scale. These things have changed, now that we +engineers are beginning to hold up our heads, as we have every reason to +do; for the prosperity and well-being of the great nations of the world +are attributable, perhaps, more to our efforts than to those of any +other class. When, in the past, the man of letters, the poet, the +orator, succeeded, by some fit expression, by some winged word, to +engage the attention of the world concerning some subject he had at +heart, the highest praise his fellow man could bestow was to cry out +to him, "Well said, well said!" But now, when, by our achievements, +commerce and industry are increased to gigantic proportions, when the +remotest peoples are brought in ever closer communication with us, when +the progress of the human race has become a mighty torrent, rushing +onward with ever accelerating speed, we glory in the yet higher praise, +"Well done, well done!" Under these circumstances, the question how a +young man is best fitted for our profession has become one of increasing +importance, and three methods have been proposed for its solution. +Formerly the only point in debate was whether the candidate should go +first to the schools and then to the workshop, or first to the shop and +then to the schools. It was difficult to arrive at any decision; for of +the many who had risen to eminence as engineers, some had adopted +one order and some the other. There remained a third course, that of +combining the school and the shop and of pursuing simultaneously the +study of theory and the exercise of practical manipulation. Unforeseen +difficulties arose, however, in the attempt to carry out this, the most +promising method. The maintenance of the shop proved a heavy expense, +which it was found could not be lessened by the manufacture of salable +articles, because the work of students could not compete with that of +expert mechanics. It would require more time than could be allotted, +moreover, to convert students into skilled workmen. Various +modifications of this combination of theory and practice, including more +or less of the Russian system of instruction in shop-work, have been +tried in different schools of engineering, but never under so favorable +conditions as the present. With characteristic caution and good +judgment, President Morton has studied the operation of the scheme +of instruction adopted in the Stevens Institute, and, noting its +deficiencies, has now supplied them with munificent liberality, giving +to it a completeness that leaves seemingly nothing that could be +improved upon, even in a prayer or a dream. Still, no one will be more +ready to admit than he who has done all this, that it is not enough to +fit up a machine shop, be it never so complete, and light it with an +electric lamp. The decision as to its efficiency must come from the +students that are so fortunate as to be admitted to it. If such young +men, earnest, enthusiastic, with every incentive to exertion and every +advantage for improvement, here, where they can feel the throbbing of +the great heart of enterprise, within sight of bridges upon which their +services will be needed, within hearing of the whistles of a score of +railroads, and the bells of countless manufactories which will want +them; if such as these, trained under such instructors and amid such +surroundings, prove to be not fitted for the positions waiting for them +to fill, it will have been definitely demonstrated that the perfect +scheme is yet unknown. + + +SPEECH OF MR. HORATIO ALLEN. + +Impressed with the very great step in advance which has been inaugurated +here this evening, I feel crowding upon me so many thoughts that I +cannot make sure that, in selecting from them, I may not leave unsaid +much that I should say, and say some things that I had better omit. Some +years ago, when asked by a wealthy gentleman to what machine-shop he had +best send his son, who was to become a mechanical engineer, I advised +him not to send him to any, but to fit up a shop for him where he could +go and work at what he pleased without the drudgery of apprenticeship, +to put him in the way of receiving such information as he needed, and +especially to let him go where he could see things break. Great, indeed, +are the advantages of those who have the opportunity of seeing things +break, of witnessing failures and profiting by them. When men have +enumerated the achievements of those most eminent in our profession the +thought has often struck me, "Ah! if we could only see that man's scrap +heap." + +There are many who are able to construct a machine for a given purpose +so that it will work, but to do this so that it will not cost too much +is an entirely different problem. To know what to omit is a rare talent. +I once found a young man who could tell students what to store up in +their minds for immediate use, and what to skim over or omit; but I +could not keep him long, for more lucrative positions are always waiting +for such men. + +The advice I gave my wealthy friend was given before the Stevens +Institute had developed in the direction it has now. The foundation of +this advice, namely, to combine a certain amount of judicious practice +with theory, is now in a fair way to be carried out, and although +things will probably not be permitted to break here, the students will +doubtless have opportunities for looking around them and supplementing +their systematic instruction here by observation abroad. + + * * * * * + + + + +LIGHT STEAM ENGINE FOR BALLOONS. + + +We here illustrate one of a couple of compound engines designed and +constructed by Messrs. Ahrbecker, Son & Hamkens, of Stamford Street, +S.E., for Captain Mojaisky, of the Russian Imperial Navy, who intends +to use them for aeronautical purposes. The larger of these engines has +cylinders 33/4 in. and 71/2 in. in diameter and 5 in. stroke, and when +making 300 revolutions per minute it develops 20 actual horse +power, while its weight is but 105 lbs. The smaller engine--the one +illustrated--has cylinders 21/2 in. and 5 in. in diameter, and 31/2 in. +stroke, and weighs 63 lbs., while when making 450 revolutions it +develops 10 actual horse power. + +The two engines are identical in design, and are constructed of forged +steel with the exception of the bearings, connecting-rods, crossheads, +slide valves and pumps, which are of phosphor-bronze. The cylinders, +with the steam passages, etc., are shaped out of the solid. The +standards, as will be seen, are of very light T steel, the crankshafts +and pins are hollow, as are also the crosshead bolts and piston rods. +The small engine drives a single-acting air pump of the ordinary type by +a crank, not shown in the drawing. The condenser is formed of a series +of hollow gratings. + +[Illustration: LIGHT STEAM ENGINE FOR AERONAUTICAL PURPOSES] + +Steam is supplied to the two engines by one boiler of the Herreshoff +steam generator type, with certain modifications, introduced by the +designers, to insure the utmost certainty in working. It is of steel, +the outside dimensions being 22 in. in diameter, 25 in. high, and weighs +142 lb. The fuel used is petroleum, and the working pressure 190 lb. per +square inch. + +The constructors consider the power developed by these engines very +moderate, on account of the low piston speed specified in this +particular case. In some small and light engines by the same makers +the piston speed is as high as 1000 ft. per minute. The engines now +illustrated form an interesting example of special designing, and +Messrs. Ahrbecker, Son, and Hamkens deserve much credit for the manner +in which the work has been turned out, the construction of such light +engines involving many practical difficulties,--_Engineering._ + + * * * * * + +Mount Baker, Washington Territory, has shown slight symptoms of volcanic +activity for several years. An unmistakable eruption is now in progress. + + * * * * * + + + + +COMPLETE PREVENTION OF INCRUSTATION IN BOILERS. + + +The chemical factory, Eisenbuettel, near Braunschweig, distributes the +following circular: "The principal generators of incrustation in boilers +are gypsum and the so-called bicarbonates of calcium and magnesium. If +these can be taken put of the water, before it enters the boiler, the +formation of incrustation is made impossible; all disturbances and +troubles, derived from these incrustations, are done away with, and +besides this, a considerable saving of fuel is possible, as clear iron +will conduct heat quicker than that which is covered with incrustation." + +J. Kolb, according to _Dingler's Polyt. Journal_, says: "A boiler with +clear sides yielded with 1 kil. coal 7.5 kil. steam, after two months +only 6.4 kil. steam, or a decrease of 17 per cent. At the same time the +boiler had suffered by continual working." + +Suppose a boiler free from inside crust would yield a saving of only +5 per cent. in fuel (and this figure is taken very low compared with +practical experiments) it would be at the same time a saving of 3c. per +cubic meter water. If the cleaning of one cubic meter water therefore +costs less than 3c., this alone would be an advantage. + +Already, for a long time, efforts have been made to find some means for +this purpose, and we have reached good results with lime and chloride of +barium, as well as with magnesia preparations. But these preparations +have many disadvantages. Corrosion of the boiler-iron and muriatic acid +gas have been detected. (Accounts of the Magdeburg Association for +boiler management.) + +Chloride of calcium, which is formed by using chloride of barium, +increases the boiling point considerably, and diminishes the elasticity +of steam; while the sulphate of soda, resulting from the use of +carbonate of soda, is completely ineffectual against the boiler iron. +It increases the boiling point of water less than all other salts, and +diminishes likewise the elasticity of steam (Wullner). + +In using magnesia preparation, the precipitation is only very slowly and +incompletely effected--one part of the magnesia will be covered by the +mire and the formed carbonate of magnesia in such a way, that it can no +more dissolve in water and have any effect (_Dingler's Polyt. Journal_, +1877-78). + +The use of carbonate of soda is also cheaper than all other above +mentioned substances. + +One milligramme equivalent sulphate of lime, in 1 liter, = 68 grammes +sulphate of lime in 1 cubic meter, requiring for decomposition: + +120 gr. (86-88 per cent.) chloride of barium of commerce--at $5.00 = +0.6c. + +Or, 50 gr. magnesia preparation--at $10.00 = 0.5c. + +Or, 55 gr. (96-98 per cent.) carbonate of soda--at $7.50 = 0.41c. + +The proportions of cost by using chloride of barium, magnesia +preparation, carbonate of soda, will be 6 : 5 : 4. + + +ARRANGEMENT FOR PURIFYING BOILER-WATER WITH LIME AND CARBONATE OF SODA. + +We need for carrying out these manipulations, according to the size +of the establishment, one or more reservoirs for precipitating the +impurities of the water, and one pure water reservoir, to take up the +purified water; from the latter reservoir the boilers are fed. The most +practical idea would be to arrange the precipitating reservoir in such +manner that the purified water can flow directly into the feeding +reservoir. + +The water in the precipitating reservoir is heated either by adding +boiling water or letting in steam up to 60 deg. C. at least. The +precipitating reservoirs (square iron vessels or horizontal +cylinders--old boilers) of no more than 4 or 41/2 feet, having a faucet 6 +inches above the bottom, through which the purified water is drawn off, +and another one at the bottom of the vessel, to let the precipitate off +and allow of a perfect cleaning. In a factory with six or seven boilers +of the usual size, making together 400 square meters heating surface, +two precipitating reservoirs, of ten cubic meters each, and one pure +water reservoir of ten or fifteen cubic meter capacity, are used. + +In twenty-four hours about 240 cubic meters of water are evaporated; we +have, therefore, to purify twenty-four precipitating reservoirs at ten +cubic meters each day, or ten cubic meters each hour. + +It is profitable to surround the reservoirs with inferior conductors of +heat, to avoid losses. + +The contents of the precipitating reservoirs have to be stirred up very +well, and for this purpose we can either arrange a mechanical stirrer +or do it by hand, or the best would be a "Korting steam stirring and +blowing apparatus." In using the latter we only have to open the valve, +whereby in a very short time the air driven through the water stirs this +up and mixes it thoroughly with the precipitating ingredients. In a +factory where boilers of only 15 to 100 square meters heating surface +are, one precipitating reservoir of two to ten cubic meters and one pure +water reservoir of three to ten cubic meters capacity are required. For +locomobiles, two wooden tubs or barrels are sufficient. + + +THE PURIFICATION OF THE WATER. + +After the required quantity of lime and carbonate of soda which is +necessary for a total precipitation has been figured out from the +analysis of the water, respectively verified by practical experiments +in the laboratory, the heated water in the reservoir is mixed with the +lime, in form of thin milk of lime, and stirred up; we have to add so +much lime, that slightly reddened litmus paper gives, after 1/4 minute's +contact with this mixture, an alkaline reaction, i.e., turns blue; now +the solution of carbonate of soda is added and again stirred well. + +After twenty or thirty minutes (the hotter the water, the quicker the +precipitation) the precipitate has settled in large flocks at the +bottom, and the clear water is drawn off into the pure water reservoir. +The precipitating and settling of the impurities can also take place in +cold water; it will require, however, a pretty long time. + +In order to avoid the weighing and slaking of the lime, which is +necessary for each precipitation, we use an open barrel, in which a +known quantity of slaked lime is mixed with three and a half or four +times its weight of water, and then diluted to a thin paste, so that one +kilogramme slaked lime is diluted to twenty-five liters milk of lime. + +Example.--If we use for ten cubic meters water, one kilogramme lime, +or in one day (in twenty-four hours), 240 cubic meters 24 kg. lime, a +vessel four or five feet high and about 700 liters capacity, in which +daily 24 kg. lime with about 100 liters water are slaked and then +diluted to the mark 600, constantly stirring, 25 liters of this mixture +contain exactly 1 kg. slaked lime. + +Before using, this milk of lime has to be stirred up and allowed to +settle for a few seconds; and then we draw off the required quantity of +milk of lime (in our case 25 liters) through a faucet about 8 inches +above the bottom, or we can dip it off with a pail. For the first +precipitate we always need the exact amount of milk of lime, which we +have figured out, or rather some more, but for the next precipitates we +do not want the whole quantity, but always less, as that part of the +lime, which does not settle with the precipitate, will be good for use +in further precipitations. It is therefore important to control the +addition of milk of lime by the use of litmus paper. If we do not add +enough lime, it prevents the formation of the flocky precipitate, and, +besides, more carbonate of soda is used. By adding too much lime, we +also use more carbonate of soda in order to precipitate the excess of +lime. We can therefore add so much lime, that there is only a very small +excess of hydrous lime in the water, and that after well stirring, a red +litmus paper being placed in the water for twenty seconds, appears only +slightly blue. After a short time of practice, an attentive person can +always get the exact amount of lime which ought to be added. On adding +the milk of lime, we have to dissolve the required amount of pure +carbonate of soda in an iron kettle, in about six or eight parts hot +water with the assistance of steam; add this to the other liquid in the +precipitating reservoirs and stir up well. The water will get clear +after twenty-five or thirty minutes, and is then drawn off into the pure +water reservoir. + + +EXAMINATION OF WATER WHICH HAS BEEN PURIFIED BY MEANS OF MILK OF LIME +AND CARBONATE OF SODA. + +In order to be convinced that the purification of the water has been +properly conducted, we try the water in the following manner. Take a +sample of the purified water into a small tumbler, and add a few +drops of a solution of oxalate of ammonia; this addition must neither +immediately nor after some minutes cause a milky appearance of the +water, but remain bright and clear. A white precipitate would indicate +that not enough carbonate of soda had been added. A new sample is taken +of the purified water and a solution of chloride of calcium added; a +milky appearance, especially after heating, would show that too much +carbonate of soda had been added. + + +RESULTS OF THIS WATER PURIFICATION. + +1. The boilers do not need to be cleaned during a whole season, as they +remain entirely free from incrustation; it is only required to avoid a +collection of soluble salts in the boiler, and therefore it is partly +drawn off twice a week. + +2. The iron is not touched by this purified water. The water does not +froth and does not stop up valves. The fillings in the joints of pipes, +etc., do not suffer so much, and therefore keep longer. + +3. The steam is entirely free from sour gases. + +4. The production of steam is easier and better. + +5. A considerable saving of fuel can soon be perceived. + +6. The cost of cleaning boilers from incrustation, and loss of time +caused by cleaning, is entirely done with. Old incrustations, which +could not be cleaned out before, get decomposed and break off in soft +pieces. + +7. The cost of this purification is covered sufficiently by the above +advantages, and besides this, the method is cheaper and surer than any +other. + +The chemical factory, Eisenbuettel, furnishes pure carbonate of soda in +single packages, which exactly correspond with the quantity, stated by +the analysis, of ten cubic meters of a certain water. The determination +of the quantities of lime and carbonate of soda necessary for a certain +kind of water, after sending in a sample, will be done without extra +charge.--_Neue Zeitung fur Ruebenzucker Industrie_. + + * * * * * + + + + +EDDYSTONE LIGHTHOUSE. + + +The exterior work on the new Eddystone Lighthouse is about two thirds +done. In the latter part of April fifty-three courses of granite +masonry, rising to the height of seventy feet above high water, had been +laid, and thirty-six courses remained to be set. The old lighthouse had +been already overtopped. As the work advances toward completion the +question arises: What shall be done with John Smeaton's famous tower, +which has done such admirable service for 120 years? One proposition is +to take it down to the level of the top of the solid portion, and +leave the rest as a perpetual memorial of the great work which Smeaton +accomplished in the face of obstacles vastly greater than those which +confront the modern architect. The London _News_ says: "Were Smeaton's +beautiful tower to be literally consigned to the waves, we should regard +the act as a national calamity, not to say scandal; and, if public funds +are not available for its conservation, we trust that private zeal and +munificence may be relied on to save from destruction so interesting +a relic. It certainly could not cost much to convey the building in +sections to the mainland, and there, on some suitable spot, to re-erect +it as a national tribute to the genius of its great architect." When +the present lighthouse was built one of the chief difficulties was in +getting the building materials to the spot. They were conveyed from +Millbay in small sailing vessels, which often beat about for days before +they could effect a landing at the Eddystone rocks, so that each arrival +called out the special gratitude of Smeaton. + + * * * * * + + + + +ROLLING-MILL FOR MAKING CORRUGATED IRON. + + +MESSRS. SCHULZ, KNAUDT & Co., of Essen, who are making an application +of corrugated iron in the construction of the interior flues of steam +boilers, have devised a new mill for the manufacture of this form of +iron plates, and which is represented in the accompanying cut, taken +from the _Deutsche Industrie Zeitung_. The supports of the two accessory +cylinders, F F, rest on two slides, G G, which move along the oblique +guides, H H. As a consequence of this arrangement, when the cylinders, F +F, are caused to approach the cylinder, D, both are raised at the same +instant. + +When the cylinders, F, occupy the position represented in the engraving +by unbroken lines, the flat plate, O, is simply submitted to pressure +between the cylinders, D and P, the cylinders, F F, then merely acting +as guides. But when, while the plate is being thus flattened between the +principal cylinders, the accessory cylinders are caused to rise, the +plate is curved as shown by the dotted lines, O' O'. To obtain a +uniformity in the position of the two cylinders, F F, the following +mechanism is employed: Each cylinder has an axle, to which is affixed a +crank, Q, connected by means of a rod, R, with the slide, G. These axles +are also provided with toothed sectors, L L, which gear with two screws, +L L, whose threads run in opposite directions. These screws are mounted +on a shaft, N, which may be revolved by any suitable arrangement. + +[Illustration: ROLLING MILL FOR MAKING CORRUGATED IRON] + + * * * * * + + + + +RAILWAY TURN-TABLE IN THE TIME OF LOUIS XIV. + + +The small engraving which we reproduce herewith from _La Nature_ is +deposited at the Archives at Paris. It is catalogued in the documents +relating to Old Marly, 1714, under number 11,339, Vol. 1. The design +represents a diversion called the _Jeu de la Roulette_ which was +indulged in by the royal family at the sumptuous and magnificent chateau +of Mary-le-Roi. + +[Illustration: PLEASURE CAR; RAILWAY AND TURN-TABLE OF THE TIME OF LOUIS +XIV.] + +According to Alex. Guillaumot the apparatus consisted of a sort of +railway on which the car was moved by manual labor. In the car, which +was decorated with the royal colors, are seen seated the ladies and +children of the king's household, while the king himself stands in the +rear and seems to be directing operations. The remarkable peculiarity to +which we would direct the attention of the reader is that this document +shows that the car ran on rails very nearly like those used on the +railways of the present time, and that a turn-table served for changing +the direction to a right angle in order to place the car under the +shelter of a small building. The picture which we reproduce, and the +authenticity of which is certain, proves then that in the time of +Louis XIV. our present railway turn-tables had been thought of and +constructed--which is a historic fact worthy of being noted. It is well +known that the use of railways in mines is of very ancient date, but we +do not believe that there are on record any documents as precise as that +of the _Jeu de la Roulette_ as to the existence of turn-tables in former +ages. + + * * * * * + + + + +NEW SIGNAL WIRE COMPENSATOR. + + +_To the Editor of the Scientific American_: + +I send you a plate of my new railway signal wire compensator. Here +in India signal wires give more trouble, perhaps, than in America or +elsewhere, by expansion and contraction. What makes the difficulty more +here is the ignorance and indolence of the point and signalmen, who +are all natives. There have been numerous collisions, owing to signals +falling off by contraction. Many devices and systems have been tried, +but none have given the desired result. You will observe the signal wire +marked D is entirely separated and independent of the wire, E, leading +to lever. On the Great Indian and Peninsula Railway I work one of these +compensators, 1,160 yards from signal, which stands on a summit the +grade of which is 1 in 150; and on the Nizam State Railway I have one +working on a signal 800 yards. This signal had previously given so much +trouble that it was decided to do away with it altogether. It stands on +top of a high cutting and on a 1,600 foot curve. + +[Illustration: Railway Signal Wire Comensator] + +I have noted on the compensator fixed at 1,160 yards, 131/4 inches +contraction and expansion. The compensator is very simple and not at all +likely to get out of order. On new wire, when I fix my compensator, I +usually have an adjusting screw on the lead to lever. This I remove +when the wire has been stretched to its full tension. I have everything +removed from lever, so there can be no meddling or altering. When +once the wire is stretched so that no slack remains between lever and +trigger, no further adjustment is necessary. + +A. LYLE, + +Chief Maintenance Inspector, Permanent Way, + +H.H. Nizam State Railway, E. India. + +Secunderabad, India, 1881. + + + + +TANGYE'S HYDRAULIC HOIST. + + +[Illustration: TANGYE'S HYDRAULIC HOIST.] + +The great merits of hydraulic hoists generally as regards safety and +readiness of control are too well known to need pointing out here. +We may, therefore, at once proceed to introduce to our readers the +apparatus of this class illustrated in the above engravings. This is +a hoist (Cherry's patent) manufactured by Messrs. Tangye Brothers, of +London and Birmingham, and which experience has proved to be a most +useful adjunct in warehouses, railway stations, hotels, and the like. +Fig. 1 of our engraving shows a perspective view of the hoist, Fig. 2 +being a longitudinal section. It will be seen that this apparatus is of +very simple construction, the motion of the piston being transmitted +directly to the winding-drum shaft by means of a flexible steel rack. +Referring to Fig. 2, F is a piston working in the cylinder, G; E is +the flexible steel rack connected to the piston, F, and gearing with a +toothed wheel, B, which is inclosed in a watertight casing having cover, +D, for convenient access. The wheel, B, is keyed on a steel shaft, C, +which passes through stuffing-boxes in the casing, and has the winding +barrel, A, keyed on it outside the casing. H is a rectangular tube, +which guides the free end of the flexible steel rack, E. The hoist is +fitted with a stopping and starting valve, by means of which water +under pressure from any convenient source of supply may be admitted or +exhausted from the cylinder. The action in lifting is as follows: The +water pressure forces the piston toward the end of the cylinder. The +piston, by means of the flexible steel rack, causes the toothed wheel +to revolve. The winding barrel, being keyed on the same shaft as the +toothed wheel, also revolves, and winds up the weight by means of the +lifting chain. Two special advantages are obtained by this simple method +of construction. In the first place, twice the length of stroke can be +obtained in the same space as compared with the older types of hydraulic +hoist; and, from the directness of the action, the friction is reduced +to a minimum. This simple method of construction renders the hoist very +compact and easily fixed; and, from the directness with which the power +is conveyed from the piston to the winding drum, and the frictionless +nature of the mechanism, a smaller piston suffices than in the ordinary +hydraulic hoists, and a smaller quantity of water is required to work +them.--_Iron_. + + * * * * * + + + + +POWER LOOM FOR DELICATE FABRICS. + + +The force with which the shuttle is thrown in an ordinary power +loom moving with a certain speed is always considerable, and, as a +consequence of the strain exerted on the thread, it is frequently +necessary to use a woof stronger than is desirable, in order that it may +have sufficient resistance. On another hand, when the woof must be very +fine and delicate the fabric is often advantageously woven on a hand +loom. In order to facilitate the manufacture of like tissues on the +power loom the celebrated Swiss manufacturer, Hanneger, has invented an +apparatus in which the shuttle is not thrown, but passed from one side +to the other by means of hooks, by a process analogous to weaving silk +by hand. A loom built on this principle was shown at work weaving silk +at the Paris Exhibition of 1878. This apparatus, represented in +the annexed figure, contains some arrangements which are new and +interesting. On each side of the woof in the heddle there is a carrier, +B. These carriers are provided with hooks, A A', having appendages, +_a a'_, which are fitted in the shuttle, O. The latter is of peculiar +construction. The upper ends of the hooks have fingers, _d d'_, which +holds the shuttle in position as long as the action of the springs, _e +e'_, continues. The distance that the shuttle has to travel includes the +breadth of the heddle, the length of the shuttle, and about four inches +in addition. The motion of the two carriers, which approach each other +and recede simultaneously, is effected by the levers, C, D, E, and C', +D', E'. The levers, E, E', are actuated by a piece, F, which receives +its motion from the main shaft, H, through the intervention of a +crank and a connecting rod, G, and makes a little more than a quarter +revolution. The levers, E, E', are articulated in such a way that +the motion transmitted by them is slackened toward the outer end and +quickened toward the middle of the loom. While the carriers, B B', are +receiving their alternate backward and forward motion, the shaft, I +(which revolves only half as fast as the main shaft), causes a lever, F +F', to swing, through the aid of a crank, J, and rod, K. Upon the two +carriers, B B', are firmly attached two hooks, M M', which move with +them. When the hook, M, approaches the extremity of the lever, F, the +latter raises it, pushes against the spring, E, and sets free the +shuttle, which, at the same moment, meets the opposite hook, _a'_, and, +being caught by it, is carried over to the other side. The same thing +happens when the carrier, B', is on its return travel, and the hook, M', +mounts the lever, F', which is then raised. + +[Illustration: POWER LOOM FOR DELICATE FABRICS.] + +As will be seen from this description, the woof does not undergo the +least strain, and may be drawn very gently from the shuttle. Neither +does this latter exert any friction on the chain, since it does not move +on it as in ordinary looms. In this apparatus, therefore, there may be +employed for the chain very delicate threads, which, in other looms, +would be injured by the shuttle passing over them. Looms constructed on +this plan have for some time been in very successful use in Switzerland. + + * * * * * + + + + +HOW VENEERING IS MADE. + + +The process of manufacture is very interesting. The logs are delivered +in the mill yard in any suitable lengths as for ordinary lumber. A steam +drag saw cuts them into such lengths as may be required by the order +in hand; those being cut at the time of our visit were four feet long. +After cutting, the logs are placed in a large steam box, 15 feet wide, +22 feet long, and six feet high, built separate from the main building. +This box is divided into two compartments. When one is filled entirely +full, the doors are closed, and the steam, supplied by the engine in the +main building, is turned on. The logs remain in this box from three to +four hours, when they are ready for use. This steaming not only removes +the bark, but moistens and softens the entire log. From the steam box +the log goes to the veneer lathe. It is here raised, grasped at each end +by the lathe centers, and firmly held in position, beginning to slowly +revolve. Every turn brings it in contact with the knife, which is gauged +to a required thickness. As the log revolves the inequalities of its +surface of course first come in contact with the keen-edged knife, and +disappear in the shape of waste veneer, which is passed to the engine +room to be used as fuel. Soon, however, the unevenness of the log +disappears, and the now perfect veneer comes from beneath the knife in +a continuous sheet, and is received and passed on to the cutting table. +This continues until the log is reduced to about a seven inch core, +which is useless for the purpose. The veneer as it comes rolling off the +log presents all the diversity of colors and the beautiful grain and +rich marking that have perhaps for centuries been growing to perfection +in the silent depths of our great forests. + +From the lathe, the veneer is passed to the cutting table, where it is +cut to lengths and widths as desired. It is then conveyed to the second +story, where it is placed in large dry rooms, air tight, except as the +air reaches them through the proper channels. The veneer is here placed +in crates, each piece separate and standing on edge. The hot air is then +turned on. This comes from the sheet iron furnace attached to the boiler +in the engine room below, and is conveyed through large pipes regulated +by dampers for putting on or taking off the heat. There is also a blower +attached which keeps the hot air in the dry rooms in constant motion, +the air as it cools passing off through an escape pipe in the roof, +while the freshly heated air takes its place from below. These rooms +are also provided with a net-work of hot air pipes near the floor. The +temperature is kept at about 165 deg., and so rapid is the drying process +that in the short space of four hours the green log from the steam box +is shaved, cut, dried, packed, and ready for shipment. + +After leaving the dry rooms it is assorted, counted, and put up in +packages of one hundred each, and tied with cords like lath, when it is +ready for shipment. Bird's-eye maple veneer is much more valuable and +requires more care than almost any other, and this is packed in cases +instead of tied in bundles. The drying process is usually a slow one, +and conducted in open sheds simply exposed to the air. Mr. Densmore's +invention will revolutionize this process, and already gives his mill a +most decided advantage. + +The mill will cut about 30,000 feet of veneer in a day, and this cut can +be increased to 40,000 if necessary. Mr. Densmore has already received +several large orders, and the rapidly increasing demand for this +material is likely to give the mill all the work it can do. The timber +used is principally curled and bird's-eye maple, beech, birch, cherry, +ash, and oak. These all grow in abundance in this vicinity, and the +beautifully marked and grained timber of our forests will find fitting +places in the ornamental uses these veneers will be put to. + + * * * * * + + + + +THE CONSTITUENT PARTS OF LEATHER. + + +The constituent parts of leather seem to be but little understood. The +opinions of those engaged in the manufacture of leather differ widely on +this question. + +Some think that tannin assimilates itself with the hide and becomes +fixed there by reason of a special affinity. Others regard the hide as +a chemical combination of gelatine and tannin. We know that the hide +contains some matters which are not ineradicable, but only need a slight +washing to detach them. + +We deem it advisable, in order to examine the hide properly so-called, +to dispense with those eradicable substances which may be regarded, to +some extent, as not germain to it, and confine our attention to the raw +stock, freed from these imperfections. + +It is well known that a large number of vegetable substances are +employed as tanning agents. Our researches have been directed to leather +tanned by means of the most important of these agents. + +Many questions present themselves in the course of such an examination. +Among others, that most important one, from a practical point of view, +of the weight the tanning agent gives to the hide, that is to say, the +result in leather of weight given to the raw material. The degree of +tannage is also to be considered; the length of time during which the +tanning agent is to be left with the hide; in short, the influence upon +the leather of the substances used in its production. That is why we +have made the completest possible analysis of different leathers. + +Besides ordinary oak bark there are used at present very different +substances, such as laurel, chestnut, hemlock, quebracho and pine bark, +sumac, etc. + +Water is an element that exists in all hides, and it is necessary to +take it into consideration in the analysis. It is present in perceptible +quantity even in dry hides. This water cannot be entirely eradicated +without injuring the leather, which will lose in suppleness and +appearance. Water should then be considered as one of the elements of +leather, but it must be understood that if it exceeds certain limits, +say 12 to 14 per cent., it becomes useless and even injurious. Moreover, +if there is any excess over the normal quantity, it becomes deceptive +and dishonest, as in such a case one sells for hides that which is +nothing but water. Supposing that a hide, instead of only 14 per cent., +contained 18 per cent. of water, it is evident that in buying 100 pounds +of such a hide one would pay for four pounds of water at the rate for +which he purchased the hide. + +There are, also, some matters soluble in air, which are formed to a +large extent from fat arising as much from the hide as from tanning +substances. The air dissolves at the same time a certain amount of +organic acid and resinous products which the hide has absorbed. After +treating with air, alcohol is used, which dissolves principally the +coloring matters, tannin which has not become assimilated, bodies +analogous to resin, and some extractive substances. + +That which remains after these methods have been pursued ought to be +regarded as the hide proper, that is to say, as the animal tissue +saturated with tannic acid. In this remainder one is able to estimate +with close precision that which belongs to the hide. The hide being an +elementary tissue of unchangeable form, it is easy, in determining the +elementary portion, to find the amount of real hide remaining in the +product. With these elements one can arrive at a solution of some of the +questions we are discussing. + +We give below, according to this method, a table showing the composition +of the different leathers exhibited at the Paris Exposition of 1878. +They are the results of careful research, and we have based our work +upon them: + + Matter Soluble Fixed + in Air Tannin + | | + | Matter Solu- | + | ble in Alcohol | + | | | + Moisture | | Gelatine | + --+-- --+-- --+-- --+-- --+-- +Steer hide, hemlock tanned (heavy leather) 10.95 4.15 19.77 39.1 26.03 +Sheepskins, sumac " (Hungarian) 10.8 10.3 12.1 40.3 26.5 +Finished calf, pine bark tanned (Hungarian) 11.2 1.7 7.4 41.6 38.1 +Steer hide, quebracho tanned (heavy leather) 11.7 1.6 11.2 43.1 32.4 + " " chestnut " " " 13.5 0.29 1.99 45.46 38.76 +Finished calfskins, + oak tanned (Chateau Renault) 12.4 0.33 3.59 46.74 36.94 +Steer hide, laurel tanned (heavy leather) 12.4 1.05 7.95 47.47 31.13 + " " oak tanned after three years in + the vats (heavy leather) 11.45 0.37 3.31 49.85 35.02 + +The following table shows the amount of leather produced by different +tannages of 100 pounds of hides: + + Pounds. +Hemlock 255.7 +Sumac 248.1 +Pine 240.3 +Quebracho 232 +Chestnut 219.9 +Oak 213.9 +Laurel 210.6 +Oak, lasting three years 206 + +It is important to mention here the large proportion of resinous matter +hemlock-tanned leather contains. This resin is a very beautiful red +substance, which communicates its peculiar color to the leather. + +We should mention here that in these calculations we assume that the +hide is in a perfectly dry state, water being a changeable element which +does not allow one to arrive at a precise result. + +These figures show the enormous differences resulting from diverse +methods of tanning. Hemlock, which threatens to flood the markets of +Europe, distinguishes itself above all. The high results attributable to +the large proportion of resin that the hide assimilates, explain in part +the lowness of its price, which renders it so formidable a competitor. +One is also surprised at the large return from sumac-tanned hides when +it is remembered in how short a time the tanning was accomplished, +which, in the present case, only occupied half an hour. + +The figures show us that the greatest return is obtained by means of +those tanning substances which are richest in resin. In short, hemlock, +sumac, and pine, which give the greatest return, are those containing +the largest amount of resin. Thus, hemlock bark gives 10.58 per cent. +of it, and sumac leaves 22.7 per cent., besides the tannin which they +contain. We know also that pine bark is very rich in resin. There is, +then, advantage to the tanner, so far as the question of result is +concerned, in using these materials. There is, however, another side to +the question, as the leather thus surcharged with resin is of inferior +quality, generally has a lower commercial value, and is often of a color +but little esteemed. + +The percentage of tannin absorbed by the different methods of tannages +appears in the following table: + +Hemlock 64.2 +Sumac 61.4 +Pine 90.8 +Quebracho 75.3 +Chestnut 85.2 +Oak 76.9 +Laurel 64.8 +Oak, three years in the vat 70.2 + +The subjoined is a statement of the gelatine and tannin in leather of +different tannages, and also shows the amount of azote or elementary +matter contained in each: + + Gelatine. Tannin. Azote. +Hemlock 60.4 39.6 10.88 +Sumac 60.4 39.6 11 +Pine bark 52.5 47.5 9.56 +Quebracho 57.1 42.9 10.4 +Chestnut 53.97 46.03 9.79 +Oak 55.87 44.13 10.24 +Laurel 60.4 39.6 10.94 +Oak, 3 years in vat 58.75 41.25 10.65 + +It is not pretended that these figures are absolutely correct, as they +often vary in certain limits even for similar products. They form, +however, a fair basis of calculation. + +As to whether leather is a veritable combination, it seems to us that +this question should be answered affirmatively. In fact, the resistance +of leather properly so-called to neutral dissolvents, argues in favor of +this opinion. + +Furthermore, the perceptible proportion of tannin remaining absorbed by +a like amount of hide is another powerful argument. It remains for us to +say here that the differences observable in the quantity of fixed tannin +ought to arise chiefly from the different natures of these tannins, +which have properties differing as do those of one plant from another, +and which really have but one property in common, that of assimilating +themselves with animal tissues and rendering them imputrescible. + +In conclusion, these researches determine the functions of resinous +matters which frequently accompany tannin; they show a very simple +method for estimating the results of one's work, as well as the degree +of tannage.--_Muntz & Schoen, in La Halle aux Cuirs_.--_Shoe & Leather +Reporter_. + + * * * * * + + + + +NEW HIGH SCHOOL FOR GIRLS, OXFORD. + + +The new High School for Girls at Oxford, built by Mr. T.G. Jackson, for +the Girls' Public Day School Company, Limited, was opened September 23, +1880, when the school was transferred from the temporary premises it had +occupied in St. Giles's. The new building stands in St. Giles's road, +East, to the north of Oxford, on land leased from University College, +and contains accommodation for about 270 pupils in 11 class-rooms, some +of which communicate by sliding doors, besides a residence for the +mistress, an office and waiting-room, a room for the teachers, cloak +rooms, kitchens, and other necessary offices, and a large hall, 50 ft. +by 30 ft., for the general assembling of the school together and for use +on speech-days and other public occasions. The principal front faces St. +Giles's road, and is shown in the accompanying illustration. The great +hall occupies the whole of the upper story of the front building, with +the office and cloak-rooms below it, and the principal entrance in the +center. The class-rooms are all placed in the rear of the building, to +secure quiet, and open on each floor into a corridor surrounding the +main staircase which occupies the center of the building. The walls +are built of Headington stone in rubble work, with dressings of brick, +between which the walling is plastered, and the front is enriched with +cornices and pilasters, and a hood over the entrance door, all of terra +cotta. The hinder part of the building is kept studiously simple and +plain on account of expense. Behind the school is a large playground, +which is provided with an asphalt tennis-court, and is picturesquely +shaded with apple-trees, the survivors of an old orchard. The builders +were Messrs. Symm & Co., of Oxford; and the terra cotta was made by +Messrs. Doulton, of Lambeth. Mr. E. Long was clerk of works.--_Building +News_. + +[Illustration: SUGGESTIONS IN ARCHITECTURE--NEW HIGH SCHOOL, OXFORD] + + * * * * * + + + + +PROGRESS IN AMERICAN POTTERY. + + +No advance in any industry has been more sure than in that of pottery +and chinaware, under the American tariff, or more rapid in the past +four or five years. It took Europe three centuries and the jealous +precautions of royal pottery proprietors to build up the great +protectorates that made their distinctive trade-marks of such value. +The earlier lusters of the Italian faience were guild privacies +or individual secrets, as was almost all the craft of the earlier +art-worker. Royal patronage in England was equivalent to a protective +tariff for Josiah Wedgwood; and everywhere the importance of guarding +the china nurseries has been understood. We have in this country +broadcast and in abundance every type of material needed for the +finest china ware, and for the finer glasses and enamels. The royal +manufactories in Europe were hard put to it sometimes for want of +discovering kaolin beds in their dominions, but the resources of the +United States in these particulars needed something more than to be +brought to light. The manipulation and washing of the clays to render +them immediately useful to the potteries depends entirely upon the +reliance of these establishments upon home materials. The Missouri +potteries have their supplies near home, but these supplies must be put +upon the market for other cities in condition to compete with the clays +of Europe. There are fine kaolin beds in Chester and Delaware counties +in this State; there are clay beds in New Jersey, and the recent needs +of Ohio potteries have uncovered fine clay in that State. This shows +that not only for the manufacture itself, but for the development of +material here, everything depends upon the stimulus that protection +gives. + +Ohio china and Cincinnati pottery are known all over the country. The +Chelsea Works, near Boston, however, are as distinguished for their +clays and faience, and for lustrous tiles especially (to be used in +household decoration) can rival the rich show that the Doulton ware made +at the Centennial. Other New England potteries are eminent for terra +cotta and granite wares. On Long Island and in New York city there are +porcelain and terra cotta factories of established fame, and the first +porcelain work to succeed in home markets was made at the still busy +factories of Greenpoint. New Jersey potteries take the broad ground of +the useful, first of all, in their manufacture of excellent granite +and cream-colored ware for domestic use, but every year turn out more +beautiful forms and more artistic work. The Etruria Company especially +have succeeded in giving the warm flesh tints to the "Parian" for busts +and statuettes, now to be seen in many shop windows. These goods ought +always to be labeled and known as American--it adds to their value with +any true connoisseur. Some of these establishments, more than others, +have the enterprise to experiment in native clays, for which the whole +trade owes their acknowledgments. + +The demand all through the country by skillful decorators for the +pottery forms to work upon, points to still greater extensions in this +business of making our own china, and to the employment and good pay of +more thousands than are now employed in it. A collection of American +china, terra cotta, etc., begun at this time and added to from year to +year, will soon be a most interesting cabinet. Both in the eastern +and western manufactories ingenious workers are rediscovering and +experimenting in pastes and glazes and colors, simply because there is a +large demand for all such, and they can be supplied at prices within the +reach of most buyers. It needs only to point out this flourishing state +of things, through the "let-alone" principle, which protection insures +to this industry, to exhibit the threatened damage of the attempt, under +cover of earthenware duties, to get a little free trade through at this +session.--_Philadelphia Public Ledger_. + + * * * * * + + + + +PHOTOGRAPHIC NOTES. + + +_Mr. Warnerke's New Discovery_.--Very happily for our art, we are at the +present moment entering upon a stage of improvement which shows that +photography is advancing with vast strides toward a position that has +the possibility of a marvelous future. In England, especially, great +advances are being made. The recent experiments of our accomplished +colleague, Mr. Warnerke, on gelatine rendered insoluble by light, after +it has been sensitized by silver bromide and developed by pyrogallic +acid, have revealed to us a number of new facts whose valuable results +it is impossible at present to foretell. It seems, however, certain that +we shall thus be able to accomplish very nearly the same effects as +those obtained by bichromatized gelatine, but with the additional +advantage of a much greater rapidity in all the operations. In my own +experiments with the new process of phototypie, I hit upon the plan of +plunging the carbon image, from which all soluble gelatine had been +removed, into a bath of pyrogallic acid, in order to still further +render impermeable the substance forming the printing surface. I also +conceived the idea of afterward saturating this carbon image with a +solution of nitrate of silver, and of subsequently treating it with +pyrogallic acid, in order to still further render impermeable the +substance forming the printing surface. But the process described by Mr. +Warnerke is quite different; by means of it we shall be able to fix +the image taken in the camera, in the same way as we develop carbon +pictures, and afterward to employ them in any manner that may be +desirable. Thus the positive process of carbon printing would be +modified in such a manner that the mixtures containing the permanent +pigment should be sensitized with silver bromide in place of potassium +bichromate. In this way impressions could be very rapidly taken of +positive proofs, and enlargements made, which might be developed in hot +water, just as in the ordinary carbon process, and at least we should +have permanent images. Mr. Warnerke's highly interesting experiments +will no doubt open the way to many valuable applications, and will +realize a marked progress in the art of photography. + +_Method for Converting Negatives Directly into Positives_.--Captain +Bing, who is employed in the topographic studios of the Ministry of +War, has devised a process for the direct conversion of negatives into +positives. The idea is not a new one; but several experimenters, and +notably the late Thomas Sutton, have pointed out the means of effecting +this conversion; it has never, however, so far as I know, been +introduced into actual practice, as is now the case. The process which +I am about to describe is now worked in the studios of the Topographic +Service. The negative image is developed in the ordinary way, but the +development is carried much further than if it were to be used as an +ordinary negative. After developing and thoroughly washing, the negative +is placed on a black cloth with the collodion side downward, and exposed +to diffuse light for a time, which varies from a few seconds to two or +three minutes, according to the intensity of the plate. Afterward the +conversion is effected by moistening the plate afresh, and then plunging +it into a bath which is thus composed: + +Water 700 cub. cents. +Potassium bichromate 30 grams. +Pure nitric acid 300 cub. cents. + +In a few minutes this solution will dissolve all the reduced silver +forming the negative; the negative image is therefore entirely +destroyed; but it has served to impress on the sensitive film beneath +it a positive image, which is still in a latent condition. It must, +therefore, be developed, and to do this, the film is treated with a +solution of-- + +Water 1,000 grams +Pyrogallic acid 25 " +Citric acid 20 " +Alcohol of 36 deg. 50 cub. cents. + +The process is carried on exactly as if developing an ordinary negative; +but the action of the developer is stopped at the precise moment when +the positive has acquired intensity sufficient for the purpose for which +it is to be used. Fixing, varnishing, etc., are then carried on the +usual way. The great advantage of this process consists in the fact of +its rendering positives of much greater delicacy than those that are +taken by contact; and, on the other hand, by means of it we are able to +avoid two distinct operations, when for certain kinds of work we require +positive plates where a negative would be of no service. M. V. Rau, +the assistant who has carried out this process under the direction of +Captain Bing, has described it in a work which has just been published +by M. Gauthier-Villars. + +_Experiments of Captain Bing on the Sensitiveness of Coal Oil_.--The +same Captain of Engineers has undertaken a series of very interesting +experiments on the sensitiveness to light of one or two substances to +which bitumen probably owes its sensitiveness, but which, contrary to +what takes place with bitumen, are capable of rendering very beautiful +half tones, both on polished zinc and on albumenized paper. These +sensitive substances are extracted by dissolving marine glue or coal-tar +in benzine. By exposure to light, both marine-glue and coal-tar turn of +a sepia color, and, in a printing-frame, they render a visible image, +which is not the case with bitumen; their solvents are in the order of +their energy; chloroform, ether, benzine, turpentine, petroleum spirit, +and alcohol. Of these solvents, benzine is the best adapted for reducing +the substances to a fluid state, so as to enable them to flow over the +zinc. The images obtained, which are permanent, and which are very much +like those of the Daguerreotype, are fixed by means of the turpentine +and petroleum spirit. They are washed with water, and then carefully +dried. It is possible to obtain prints with half-tones in fatty ink by +means of plates of zinc coated with marine-glue. Some attempts in this +direction were shown to me, which promised very well in this respect. We +are, therefore, in the right road, not only for economically producing +permanent prints on paper, but also for making zinc plates in which the +phototype film of bichromatized gelatine is replaced by a solution of +marine-glue and benzine. The substance known in commerce under the name +of pitch or coal-tar will produce the same results. + +_Bitumen Plates_.--A new method of making bitumen plates by contact has +also been introduced into the topographical studios. The plan, or the +original drawing, is placed against a glass plate, coated with a mixture +of bitumen and of marine-glue dissolved in benzine. The marine-glue +gives the bitumen greater pliancy, and prevents it from scaling off when +rubbed, particularly when the plate is retouched with a dry point. +These bitumen plates are so thoroughly opaque to the penetration of the +actinic rays, that the printing-frame may be left for any time in full +sunlight without any fear of fog being produced on the zinc plate from +which the prints are to be taken. + +_Method for Topographic Engraving by Commandant de la Noe_.--Before +leaving the interesting studios of which I have been speaking, I ought +to mention a very ingenious application which has been made of a process +called _topogravure_, invented by Commandant de la Noe, who is the +director of this important department. A plate of polished zinc is +coated with bitumen in the usual way, and then exposed directly to the +light under an original drawing, or even under a printed plan. So soon +as the light has sufficiently acted, which may be seen by means of +photometric bands equally transparent at the plate, all the bitumen not +acted upon is dissolved. As it is a positive which has acted as matrix, +the uncovered zinc indicates the design, and the ground remains coated +with insoluble bitumen. The plate is then etched with a weak solution +of nitric acid in water, and the lines of the design are thus slightly +engraved; the surface is then re-coated with another layer of bitumen, +which fills up all the hollows, and is then rubbed down with charcoal. +All the surface is thus cleaned off, and the only bitumen which remains +is that in the lines, which, though not deep, are sufficiently so to +protect the substance from the rubbing of the charcoal. When this +is done we have an engraved plate which can be printed from, like a +lithographic stone; it is gummed and wetted in the usual way, and it +gives prints of much greater delicacy and purity than those taken +directly from the bitumen. The ink is retained by the slight projection +of the surface beyond the line, so that it cannot spread, and a kind of +copper plate engraving is taken by lithographic printing. Besides, in +arriving at this result, there is the advantage of being able to use +directly the original plans and drawings, without being obliged to have +recourse to a plate taken in the camera; the latter is indispensable +for printing in the usual way on bitumen where the impression on the +sensitive film is obtained by means of a negative. It will be seen that +this process is exceedingly ingenious, and not only is its application +very easy, but all its details are essentially practical. + +_Succinate of Iron Developer_.--I have received a letter from M. +Borlinetto, in which he states that he has been induced by the analogy +which exists between oxalic and succinic acids to try whether succinate +of iron can be substituted for oxalate of iron as a developer. To prove +this he prepared some proto-succinate of iron from the succinate of +potassium and proto-sulphate of iron, following the method given by Dr. +Eder for the preparation of his ferrous oxalate developer. He carried +out the development in the same way as is done by the oxalate, and +he found that the succinate of iron is even more energetic than the +oxalate. The plate develops regularly with much delicacy, and gives a +peculiar tone. It is necessary to take some fresh solution at every +operation, on account of the proto-succinate of iron being rapidly +converted into per-succinate by contact with the air. + +_Method of Making Friable Hydro-Cellulose_.--At the meeting of the +Photographic Society of France, M. Girard showed his method of preparing +cellulose in a state of powder, specially adapted for the production of +pyroxyline for making collodion. Carded cotton-wool is placed in water, +acidulated with 3 per cent. of sulphuric or nitric acid, and is left +there from five to fifteen seconds; it is then taken out and laid on a +linen cloth, which is then wrung so as to extract most of the liquid. In +this condition there still remains from 30 to 40 per cent. of acidulated +water; the cotton is divided into parcels and allowed to dry in the open +air until it feels dry to the touch, though in this condition it still +contains 20 per cent. of water. It is next inclosed in a covered jar, +which is heated to a temperature of 65 deg. C.; the desiccation therefore +takes place in the closed space, and the conversion of the material +is completed in about two or three hours. In this way a very perfect +hydro-cellulose is obtained, and in the best form for producing +excellent pyroxyline.--_Corresp. Photo Mews_. + + * * * * * + + + + +PHOTO TRACINGS IN BLACK AND COLOR. + + +Two new processes for taking photo tracings in black and color have +recently been published--"Nigrography" and "Anthrakotype"--both of which +represent a real advance in photographic art. By these two processes we +are enabled for the first time to accomplish the rapid production of +positive copies in black of plans and other line drawings. Each of +these new methods has its own sphere of action; both, therefore, should +deserve equally descriptive notices. + +For large plans, drawn with lines of even breadth, and showing no +gradated lines, or such as shade into gray, the process styled +"nigrography," invented by Itterbeim, of Vienna, and patented both +in Germany and Austria, will be found best adapted. The base of this +process is a solution of gum, with which large sheets of paper can be +more readily coated than with one of gelatine; it is, therefore, very +suitable for the preparation of tracings of the largest size. The paper +used must be the best drawing paper, thoroughly sized, and on this the +solution, consisting of 25 parts of gum arabic dissolved in 100 parts of +water, to which are added 7 parts of potassium bichromate and I part of +alcohol, is spread with a broad, flat brush. It is then dried, and if +placed in a cool, dark place will keep good for a long time. When used, +it is placed under the plan to be reproduced, and exposed to diffused +light for from five to ten minutes--that is to say, to about 14 deg. of +Vogel's photometer; it is then removed and placed for twenty minutes in +cold water, in order to wash out all the chromated gum which has not +been affected by light. By pressing between two sheets of blotting-paper +the water is then got rid of, and if the exposure has been correctly +judged the drawing will appear as dull lines on a shiny ground. After +the paper has been completely dried it is ready for the black color. +This consists of 5 parts of shellac, 100 parts of alcohol, and 15 parts +of finely-powdered vine-black. A sponge is used to distribute the color +over the paper, and the latter is then laid in a 2 to 3 per cent. bath +of sulphuric acid, where it must remain until the black color can be +easily removed by means of a stiff brush. All the lines of the drawing +will then appear in black on a white ground. These nigrographic tracings +are very fine, but they only appear in complete perfection when the +original drawings are perfectly opaque. Half-tone lines, or the marks +of a red pencil on the original, are not reproduced in the nigrographic +copy. + +"Anthrakotype" is a kind of dusting-on process. It was invented by Dr. +Sobacchi, in the year 1879, and has been lately more fully described by +Captain Pizzighelli. This process--called also "Photanthrakography"--is +founded on the property of chromated gelatine which has not been acted +on by light to swell up in lukewarm water, and to become tacky, so that +in this condition it can retain powdered color which had been dusted +on it. Wherever, however, the chromated gelatine has been acted on by +light, the surface becomes horny, undergoes no change in warm water, and +loses all sign of tackiness. In this process absolute opacity in +the lines of the original drawing is by no means necessary, for it +reproduces gray, half-tone lines just as well as it does black ones. +Pencil drawings can also be copied, and in this lies one great advantage +of the process over other photo-tracing methods, for, to a certain +extent, even half-tones can be produced. + +For the paper for anthrakotype an ordinary strong, well-sized paper must +be selected. This must be coated with a gelatine solution (gelatine 1, +water 30 parts), either by floating the paper on the solution, or by +flowing the solution over the paper. In the latter case the paper is +softened by soaking in water, is then pressed on to a glass plate placed +in a horizontal position, the edges are turned up, and the gelatine +solution is poured into the trough thus formed. To sensitize the +paper, it is dipped for a couple of minutes in a solution of potassium +bichromate (1 in 25), then taken out and dried in the dark. + +The paper is now placed beneath the drawing in a copying-frame, and +exposed for several minutes to the light; it is afterward laid in cold +water in order to remove all excess of chromate. A copy of the original +drawing now exists in relief on the swollen gelatine, and, in order to +make this relief sticky, the paper is next dipped for a short time in +water, at a temperature of about 28 deg. or 30 deg. C. It is then laid on a +smooth glass plate, superficially dried by means of blotting-paper, and +lamp-black or soot evenly dusted on over the whole surface by means of +a fine sieve. Although lamp-black is so inexpensive and so easily +obtained, as material it answers the present purpose better than any +other black coloring substance. If now the color be evenly distributed +with a broad brush, the whole surface of the paper will appear to be +thoroughly black. In order to fix the color on the tacky parts of the +gelatine, the paper must next be dried by artificial heat--say, by +placing it near a stove--and this has the advantage of still further +increasing the stickiness of the gelatine in the parts which have not +been acted upon by light, so that the coloring matter adheres even more +firmly to the gelatine. When the paper is thoroughly dry, place it in +water, and let it be played on by a strong jet; this removes all the +color from the parts which have been exposed to the light, and so +develops the picture. By a little gentle friction with a wet sponge, the +development will be materially promoted. + +A highly interesting peculiarity of this anthrakotype process is the +fact that a copy, though it may have been incorrectly exposed, can +still be saved. For instance, if the image does not seem to be vigorous +enough, it can be intensified in the simplest way; it is only necessary +to soak the paper afresh, then dust on more color, etc.; in short, +repeat the developing process as above described. In difficult cases the +dusting-on may be repeated five or six times, till at last the desired +intensity is obtained. + +By this process, therefore, we get a positive copy of a positive +original in black lines on a white ground. Of course, any other coloring +material in a state of powder may be used instead of soot, and then a +colored drawing on a white ground is obtained. Very pretty variations of +the process may be made by using gold or silver paper, and dusting-on +with different colors; or a picture may be taken in gold bronze powder +on a white ground. In this way colored drawings may be taken on a gold +or a silver ground, and very bright photo tracings will be the result. +Some examples of this kind, that have been sent us from Vienna, are +exceedingly beautiful. + +Summing up the respective advantages of the two processes we have above +described, we may say that "nigrography" is best adapted for +copying drawings of a large size; the copies can with difficulty be +distinguished from good autographs, and they do not possess the bad +quality of gelatine papers--the tendency to roll up and crack. Drawings, +however, which have shadow or gradated lines cannot be well produced by +this process; in such cases it is better to adopt "anthrakotype," with +which good results will be obtained.--_Photographic News_. + + * * * * * + + + + +ON M. C. FAURE'S SECONDARY BATTERY. + + +The researches of M. Gaston Plante on the polarization of voltameters +led to his invention of the secondary cell, composed of two strips of +lead immersed in acidulated water. These cells accumulate, and, so to +speak, store up the electricity passed into them from some outside +generator. When the two electrodes are connected with any source of +electricity the surfaces of the two strips of lead undergo certain +modifications. Thus, the positive pole retains oxygen and becomes +covered with a thin coating of peroxide of lead, while the negative pole +becomes reduced to a clean metallic state. + +Now, if the secondary cell is separated from the primary one, we have a +veritable voltaic battery, for the symmetry of the poles is upset, and +one is ready to give up oxygen and the other eager to receive it. When +the poles are connected, an intense electric current is obtained, but +it is of short duration. Such a cell, having half a square meter of +surface, can store up enough electricity to keep a platinum wire 1 +millim. in diameter and 8 centims. long, red-hot for ten minutes. M. +Plante has succeeded in increasing the duration of the current by +alternately charging and discharging the cell, so as alternately to +form layers of reduced metal and peroxide of lead on the surface of the +strip. It was seen that this cell would afford an excellent means for +the conveyance of electricity from place to place, the great drawback, +however, being that the storing capacity was not sufficient as compared +with the weight and size of the cell. This difficulty has now been +overcome by M. Faure; the cell as he has improved it is made in the +following manner: + +The two strips of lead are separately covered with minium or some other +insoluble oxide of lead, then covered with an envelope of felt, firmly +attached by rivets of lead. These two electrodes are then placed near +each other in water acidulated with sulphuric acid, as in the Plante +cell. The cell is then attached to a battery so as to allow a current +of electricity to pass through it, and the minium is thereby reduced to +metallic spongy lead on the negative pole, and oxidized to peroxide of +lead on the positive pole; when the cell is discharged the reduced lead +becomes oxidized, and the peroxide of lead is reduced until the cell +becomes inert. + +The improvement consists, as will be seen, in substituting for strips +of lead masses of spongy lead; for, in the Plante cell, the action is +restricted to the surface, while in Faure's modification the action is +almost unlimited. A battery composed of Faure's cells, and weighing 150 +lb., is capable of storing up a quantity of electricity equivalent to +one horsepower during one hour, and calculations based on facts in +thermal chemistry show that this weight could be greatly decreased. A +battery of 24 cells, each weighing 14 lb., will keep a strip of platinum +five-eighths of an inch wide, one-thirty-second of an inch thick, and 9 +ft. 10 in. long, red-hot for a long time. + +The loss resulting from the charging and discharging of this battery is +not great; for example, if a certain quantity of energy is expended in +charging the cells, 80 per cent. of that energy can be reproduced by the +electricity resulting from the discharge of the cells; moreover, the +battery can be carried from one place to another without injury. A +battery was lately charged in Paris, then taken to Brussels, where it +was used the next day without recharging. The cost is also said to be +very low. A quantity of electricity equal to one horse power during an +hour can be produced, stored, and delivered at any distance within 3 +miles of the works for 11/2d. Therefore these batteries may become useful +in producing the electric light in private houses. A 1,250 horsepower +engine, working dynamo-machines giving a continuous current, will in one +hour produce 1,000 horse-power of effective electricity, that is to +say 80 per cent. of the initial force. The cost of the machines, +establishment, and construction will not be more than L40,000, and the +quantity of coal burnt will be 2 lb. per hour per effective horse-power, +which will cost (say) 1/2d. The apparatus necessary to store up the force +of 1,000 horses for twenty-four hours will cost L48,000, and will weigh +1,500 tons. This price and these weights may become much less after a +time. The expense for wages and repairs will be less than 1/4d. per hour +per horse-power, which would be L24 a day, or L8,800 a year; thus the +total cost of one horse-power for an hour stored up at the works is +3/4d. Allowing that the carriage will cost as much as the production and +storing, we have what is stated above, viz., that the total cost within +3 miles of the works is 11/2d. per horse-power per hour. This quantity of +electricity will produce a light, according to the amount of division, +equivalent to from 5 to 30 gas burners, which is much cheaper than +gas.--_Chemical News_. + + * * * * * + + + + +PHYSICAL SCIENCE IN OUR COMMON SCHOOLS. + +[Footnote: Read before the State Normal Institute at Winona, Minnesota, +April 28, 1881, by Clarence M. Boutelle, Professor of Mathematics and +Physical Science in the State Normal School.] + + +Very little, perhaps, which is new can be said regarding the teaching +of physical science by the experimental method. Special schools for +scientific education, with large and costly laboratories, are by no +means few nor poorly attended; scientific books and periodicals are +widely read; scientific lectures are popular. But, while in many schools +of advanced grade, science is taught in a scientific way, in many others +the work is confined to the mere study of books, and in only a few of +our common district schools is it taught at all. + +I shall advocate, and I believe with good reason, the use of apparatus +and experiments to supplement the knowledge gained from books in schools +where books are used, the giving of lessons to younger children who do +not use books, and the giving of these lessons to some extent in all +our schools. And the facts which I have gathered together regarding the +teaching of science will be used with all these ends in view. + +Physics--using the term in its broadest sense--has been defined as the +science which has for its object the study of the material world, the +phenomena which it presents to us, the laws which govern (or account +for) these phenomena, and the applications which can be made of either +classes of related phenomena, or of laws, to the wants of man. Thus +broadly defined, physics would be one of two great subjects covering the +whole domain of knowledge. The entire world of matter, as distinguished +from the world of mind, would be presented to us in a comprehensive +study of physics. + +I shall consider in this discussion only a limited part of this great +subject. Phenomena modified by the action of the vital force, either in +plants or in animals, will be excluded; I shall not, therefore, consider +such subjects as botany or zooelogy. Geology and related branches will +also be omitted by restricting our study to phenomena which take place +in short, definite, measurable periods of time. And lastly, those +subjects in which, as in astronomy, the phenomena take place beyond +the control of student and teacher, and in which their repetition at +pleasure is impossible, will not be considered. Natural philosophy, or +physics, as this term is generally used, and chemistry, will, therefore, +be the subjects which we will consider as sources from which to draw +matter for lessons for the children in our schools. + +The child's mind has the receptive side, the sensibility, the most +prominent. His senses are alert. He handles and examines objects about +him. He sees more, and he learns more from the seeing, than he will in +later years unless his perceptive powers are definitely trained and +observation made a habit. His judgment and his will are weak. He reasons +imperfectly. He chooses without appropriate motives. He needs the +building up and development given by educational training. _Nature +points out the method._ + +Sensibility being the characteristic of his mind, we must appeal to him +through his senses. We must use the concrete; through it we must act +upon his weak will and immature judgment. From his natural curiosity we +must develop attention. His naturally strong perceptive powers must be +made yet stronger; they must be led in proper directions and fixed upon +appropriate objects. He must be led to appreciate the relation between +cause and effects--to associate together related facts--and to state +what he knows in a definite, clear, and forcible manner. + +Object lessons, conversational lessons, lessons on animals, lessons +based on pictures and other devices, have been used to meet this demand +of the child's mental make up. Good in many respects, and vastly better +than mere book work, they have faults which I shall point out in +connection with the corresponding advantages of easy lessons in the +elements of science. I shall not quibble over definitions. Object +lessons may, perhaps, properly be said to include lessons such as it +seems to me should be given--lessons drawn from natural philosophy or +chemistry--but I use the term here in the sense in which it is often +used, as meaning lessons based upon some object. A thimble, a knife, a +watch, for instance, each of these being a favorite with a certain class +of object teachers, may be taken. + +The objections are: + +1. Little new knowledge can be given which is simple and appropriate. +Most children already know the names of such objects as are chosen, +the names of the most prominent parts, the materials of which they are +composed and their uses. Much that is often given should be omitted +altogether if we fairly regard the economy of the child's time and +mental strength. It doesn't pay to teach children that which isn't worth +remembering, and which we don't care to have them remember. + +2. Study of the qualities of materials is a prominent part of lessons on +objects. Such study is really the study of physical science, but with +objects such as are usually selected is a very difficult part to give +to young children. Ask the student who has taken a course in chemistry +whether the study of the qualities of metals and their alloys is easy +work. Ask him how much can readily be shown, and how much must be taken +on authority. Have him tell you how much or how little the thing itself +suggests, and how much must he memorized from the mere book statement +and with difficulty. Study of materials is good to a certain extent, but +it is often carried much too far. + +Consider a conversational lesson on some animal. Lessons are sometimes +given on cats. As an element in a reading lesson--to arouse interest--to +hold the attention--to secure correct emphasis and inflection--to make +sure of the reading being good: such work is appropriate. But let us see +what the effect upon the pupil is as regards the knowledge he gains +of the cat, and the effect upon his habits of thought and study. The +student gives some statement as to the appearance--the size--or some +act of his cat. It is usually an imperfect statement drawn from the +imperfect memory of an imperfect observation. And the teacher, having +only a _general knowledge_ of the habits of cats, can correct in only +a general way. Thus habits of faulty and incorrect observation and +inaccurate memory are fastened upon the child. It is no less by the +correction of the false than by the presenting of the true, that we +educate properly. + +Besides this there is the fact that traits, habits, and peculiarities +of animals are not always manifested when we wish them to be. Suppose +a teacher asks a child to notice the way in which a dog drinks, for +example; the child may have to wait until long after all the associated +facts, the reasons why this thing was to be observed--the lesson as a +whole of which this formed a part--have all grown dim in the memory, +before the chance for the observation occurs. + +Pictures are less valuable as educational aids than objects; at best +they are but partially and imperfectly concrete. The study of pictures +tends to cultivate the imagination and taste, but observation and +judgment are but little exercised. + +A comparison of the kind of knowledge gained in either of the above ways +with that gained by a study of science as such, will make some of the +advantages of the latter evident. An act of complete knowledge consists +in the identifying of an attribute with a subject. Attributes of +quality--of condition--of relation, may be gained from lessons in which +objects or pictures are used. Attributes of action which are unregulated +by the observer may be learned from the study of animals. But very +little of actions and changes which can be made to take place under +specified conditions, and with uniformity of result, can be learned +until physical science is drawn upon. + +And yet consider the importance of such study. Changes around him appeal +most strongly to the child. "Why _does_ this thing _do_ as it _does_?" +is more frequent than "Why _is_ this thing as it _is_?" He sees changes +of place, of form, of size, of composition, taking place; his curiosity +is aroused; and he is ready to study with avidity, and in a systematic +manner, the changes which his teacher may present to him. Consider +the peculiarities belonging to the study of changes of any sort. The +interest is held, for the mind is constantly gaining the new. The +attention cannot be divided--all parts of the change, all phases of the +action, must be known, and to be known must be _observed_; while in +other forms of lessons the attention may be diverted for a moment to +return to the consideration of exactly what was being observed before. +It goes without saying that in one case quick and accurate observation, +a retentive memory, and the association of causes and effects follow, +and that in the other they do not. + +I advocate, therefore, the teaching of physical science in our +schools--_in all our schools_. Physical science taught by the +experimental method. + +An experiment has been defined as a question put to Nature, a question +asked in _things_ rather than in _words_, and so conditioned that no +uncertain answer can be given. Nature says that all matter gravitates, +not in words, but in the swing of planets around the sun, and in the +leap of the avalanche. And men have devised ingenious machines through +which Nature may tell us the invariable laws of gravitation, and give +some hint as to why it is true. + +There are two kinds of experiments, and two corresponding kinds of +investigators. + +I. In original investigation there are the following elements: + +1. The careful determination of all the conditions under which the +experiment takes place. + +2. The observation of exactly what happens, with a painstaking +elimination of all previous notions as to what ought to happen. + +3. The change of conditions, one at a time, with a comparison of the +results obtained with the changes made, in order to determine that each +condition has been given just its appropriate weight in the experiment. + +4. The classification and explanation of the result. + +5. The extension of the knowledge gained by turning it to investigations +suggested by what has already been learned. + +6. The practical application of the knowledge gained. + +II. In ordinary experiments for educational purposes the experimenter +follows in a general way in the footsteps of the original investigator. +There are the following elements to be considered: + +1. The arrangement of conditions in general imitation of the original +investigator. This arrangement needs only to be general. For example, if +an original investigation were undertaken to determine the composition +of a metallic oxide, the metal and the oxygen would both be carefully +saved to be measured and weighed and fully tested. The ordinary +experiment would be considered successful if oxygen and the metal were +shown to result. + +2. The careful consideration of what should happen. + +3 The determination that the expected either does or does not happen, +with examination of reasons and elimination of disturbing causes in the +latter case. + +4. The accepting as true of the classification and explanation already +given. Theories, explanations, and laws are thus accepted every day by +minds which could never have originated either them or the experiments +from which they were derived. + +The method of original investigation, strictly considered, presents +many difficulties. A long course of preliminary training--a thorough +knowledge of what has been done in a given field already--a quick +imagination--a genius for devising forms of apparatus which will enable +him to work well under particular conditions in the most simple and +effective way--the faculty of suspending judgment, and of seeing +what happens, all that happens, and just how it +happens--patience--caution--courage--quick judgment when a completed +experiment presses for an explanation--these are some of the +characteristics which must belong to the original worker. + +Were we all capable of doing such work there would be these advantages, +among others, of studying for ourselves: + +1. What we find out for ourselves we remember longer and recall more +readily than what we acquire in any other way. This advantage holds true +whether the facts learned are entirely new or only new to us. Almost +every man whose life has been spent in study has a store of facts which +he discovered, and on which he built hopes of future greatness until +he found out later that they were old to the knowledge of the world he +lived in. And these things are among those which will remain longest in +his memory. + +2. Associated facts would be learned in studying in this way which would +remain unknown otherwise. + +But all the advantages would be associated with disadvantages too. Long +periods of time would have to be given for comparatively small results. +The history of science is full of instances in which years were spent in +the elaboration of some law, or principle, or theory which the school +boy of to-day learns in an hour and recites in a breath. Why does water +rise in a pump? Do all bodies, large and small, fall equally fast? The +principles which answer and explain such questions can be made so clear +and evident to the mind of a pupil that he would almost fancy they must +have been known from the first instead of having waited for the hard, +earnest labor of intellectual giants. And science has gone on, and +for us and for our pupils would still go on, only as accompanied with +numerous mistakes and disappointments. + +What method shall we adopt in the teaching of science? It must +differ according to the age and capacity of the pupils. An excellent +modification of the method of original investigation may be arranged as +follows: + +The children are put in possession of all facts relating to conditions, +the teacher explaining them as much as may be necessary. The experiment +is performed, the pupils being required to observe exactly what takes +place, the experiments selected being of such a nature that any previous +judgment as to what ought to occur is as nearly impossible as may be. We +predict from knowledge, real or supposed, of facts which are associated +in our minds with any new subject under consideration. Children often +know in a general, vague, and indefinite way that which, for the sake of +a full and systematic knowledge, we may desire them to study. What +they know will unconsciously modify their expectations, and their +expectations in turn may modify their observations. We are apt to +believe that happens which we expect will happen. There ought to be no +difficulty, however, in finding simple and appropriate experiments with +which the child is entirely unacquainted, and in which anything beyond +the wildest guess work is, for him, impossible. The principal use which +can be made of this method is in the mere observation of what takes +place. Nothing which the child notices correctly need be rejected, +no matter how far removed from the chief event on the object of the +experiment. Care that the pupil shall see all, and separate the +essential from the accidental, is all that is necessary. + +But the original investigator assigns reasons, and with care the +children may be allowed to attempt that. This, however, should not be +carried far; incorrect explanations should be criticised; and the class +should at length be given all the elements of the correct explanation +which they have not determined for themselves. Later, pupils should be +encouraged to name related phenomena, to mention things which they +have seen happen which are due to associated causes, and to suggest +variations for the experiment and tests for its explanation. Good +results may be made to follow this kind of work even with very young +pupils. A child grows in mental strength by using the powers he has, and +mistakes seen to be such are not only steps toward a correct view of the +subject under consideration, but are steps toward that habit of mind +which spontaneously presents correct views at once in study which comes +later in life. + +Another method is this: The pupil may know what is expected to happen, +as well as the conditions given, and held responsible for an observation +of what does happen and a comparison of what he really observes with +what he expects to observe. Explanations are usually given a class, +often in books with which they are furnished, instead of being drawn +from them, in whole or in part, by questioning, when physical science is +studied in this way. Indeed, this method is a necessity when text books +are used, unless experiments from some outside source are introduced. + +Who shall perform the experiments? With young pupils everywhere, and +in most of our common, and even in many of our graded schools, the +experiments must be performed by the teacher. With young pupils the time +is too limited, and the responsibility and necessary care too great to +permit of any other plan being practical. In many of our schools the +small supply of apparatus renders this necessary even with larger +pupils. Added to the reasons already given is the important one that in +no other way--by no other plan--can the teacher be as readily sure that +his pupils observe and reason fully for themselves. In this normal +school a course in physics, in which the experiments are all performed +in the class room by the teacher, is followed by a course in chemistry, +in which the members of the class perform the experiments for themselves +in the laboratory. And, notwithstanding the age, maturity, and previous +observation of the pupils, a great deal must be done both in the +laboratory and in the recitation room to be sure that all that happens +is seen--that the purpose is clearly held in the mind--that the reason +is fully understood. + +With older pupils and greater facilities, however, the experiments +should be performed by the pupils themselves. Constant watchfulness is +necessary, it is true, to insure to the pupil the full educational +value of the experiment. With this watchfulness it can be done, and the +advantages are numerous. Among them are: + +1. The learning of the use and care of apparatus. + +2. The learning of methods of actual construction, from materials at +hand, of some of the simpler kinds of apparatus. + +3. The learning of the importance of careful preparation. An experiment +may be performed in a few minutes before a class which has taken an hour +or more of time in its preparation. The pupil fully appreciates its +importance, and is in the best condition to remember it only when he +has had a part of the hard work attending that preparation. Again, +conditions under which an experiment is successfully performed are often +not appreciated when merely stated in words. "To prepare hydrogen gas, +pass a thistle tube and a delivery tube through a cork which fit tightly +in the neck of a bottle," etc., is simple enough. Let a pupil try with a +cork which does not fit tightly and he will never forget that condition. + +4. The learning of the importance of following directions. Chemistry, +especially, is full of those cases where this means everything. +Sometimes, not often in experiments performed in school, however, it may +mean even life or death. + +The time for experiments should be carefully considered. When performed +by the teacher they should be taken up during the recitation: + +1. If used as a foundation to build upon, at the beginning of the +lesson. + +2. If used as a summary, at the close. + +3. They should be closely connected with the points which they +illustrate. + +4. When very short, or when so difficult as to demand the whole +attention of the teacher, they may be given and afterward discussed. If +long or easy, they may be discussed while the work is going on. Changes +which take place slowly, as those which are brought about by the gradual +action of heat, for instance, are best taken up in this latter way. + +5. Exceptions may be necessary, as when experiments which demand special +preparation immediately before they are presented are given when the +recitation begins, or cases in which experiments are kept until near the +close of a recitation, when the teacher finds that attention flags and +the lesson seems to have lost its interest to the pupils as soon as the +experiments have been given. + +When performed by the pupils themselves, experiments should come before +the recitation as a part of the preparation for the work of the class +room. + +Even in those cases in which the teacher performs the work, opportunity +should be given, from time to time, for the performing of the experiment +by the pupils themselves. This can be done in several ways. During the +course in physics here I am in the habit of leaving apparatus on the +table in my room for at least one day, often for a longer time, and of +giving permission to my class to perform the experiments for themselves +when their time permits and the nature of the experiment makes it an +advantage to get a nearer view than was possible in the class work. I +leave it to them to decide when to perform the experiments, or whether +it is to their advantage to take the time to perform them at all. I make +no attempt to watch either pupils or apparatus, although I would +often assist or explain at intermissions or during the afternoon. The +apparatus was largely used, and the effect on recitations was a good +one. For advanced pupils, and those who can be fully trusted, the plan +is a good one. The only question is the safety of the apparatus; each +teacher can decide for himself regarding the advisability of the plan +for his own school. + +With smaller pupils their own safety may render it best to keep +apparatus out of their hands, except under the immediate direction of +the teacher. With all pupils that is, doubtless, the best plan where +chemicals are concerned. + +Another method is to allow pupils to assist the teacher in the +preparation of experiments, to call occasionally upon members of the +class to come forward and give the experiment in the place of the +teacher, and to encourage home work relating to experiments. This latter +is often spontaneous on the part of older pupils, and can be brought +about with the smaller ones by the use of a little tact; many of the +toys of the present day have some scientific principle at bottom; let +the teacher find out what toys his young pupils have, and encourage them +to use them in a scientific way. + +In whatever ways experiments be used, the class should be made to +consider the following elements as important in every case: + +1. The purpose of the experiment. The same experiment may be performed +at one time for one purpose, at another time for another. The purpose +intended should be made the prominent thing, all others being +subordinated to it. Many chemical reactions, for instance, can be made +to yield either one of two or more substances for study or examination, +or use, while it may be the purpose of the experiment to close only one +of them. + +2 The apparatus. All elements should be considered. The necessary should +be separated from that which may vary. In cases where the various parts +must have some definite relation to the others as regards size or +position, all that should be considered with care. In complex apparatus +the exact office of each part should be understood. + +3. A clear understanding of what happens. To this I have already +referred. + +4. Why it happens. + +5. In what other way it might be made to happen. In chemistry almost +every substance can be prepared in several different ways. The common +method is in most cases made so by some consideration of convenience, +cheapness, or safety. Often only one method is considered in one place +in a text book. In a review, however, several methods can be associated +together. Tests, uses, etc., will vary, too, and should be studied with +that fact in view. In physics phenomena illustrating a given principle +can usually be made to take place in several different ways. Often very +simple apparatus will do to illustrate some fact for which complex and +costly apparatus would be convenient. In such case the study of the +experiment with that fact in view becomes important to us who need to +simplify apparatus as much as possible. + +6. Special precautions which may be necessary. Some experiments always +work well, even in the hands of those not used to the work. Others are +successful--sometimes safe, even--only when the greatest care is taken. +Substances are used constantly in work in chemistry which are deadly +poisons, others which are gaseous and will pass through the smallest +holes. In physics the experiments usually present fewer difficulties of +this sort. But special care is necessary to complete success here. + +7. Other things shown by the experiment. While the main object should +be kept in most prominent view in all experimental work, the fullest +educational value will come only when all that can be learned by the use +of an experiment is carefully considered. + +In selecting just the work to be taken up with a given class of +children, attention must be paid to the selection of the appropriate +matter to be presented and the well adapted method of presenting it. The +following points should be carefully considered: + +1. The matter must be adapted to the capacity of the child. This must be +true both as regards the quality and the quantity. The tendency will be +to teach too much when the matter presented is entirely new, but too +little in many cases where the pupil already knows the subject in a +general way. Matter is valuable only when given slowly enough to permit +of its being fully understood and memorized, while on the other hand +method is valuable only when it secures the development of attention and +the various faculties of the child's mind by presenting a sufficient +amount of the new. + +2. The work must be based on what is already known. This, one of the +best known of the principles of teaching, is of at least as great +importance in physical science as in any other department of knowledge. +It seems to me in many cases to be more important here than elsewhere. +It is not necessary to reach each point by passing over every other +point usually considered. Lessons in electricity or sound, for instance, +can be given to children who have done nothing with other parts of +science. But a natural beginning must be made, and an orderly sequence +of lessons adopted. Children will not do what adults would find almost +impossible in covering gaps between lessons. + +Science may be compared to a great temple. Pillars, each built of many +curiously joined stones, standing at the very entrance, represent the +departments of science so far as man has studied them. We need not dig +down and study the foundations with the children; we need not study +every pillar nor choose any particular one rather than some other; but +we must learn something of every stone--of each great fact--in the +pillar we select, be it ever so little. The original investigator climbs +to stones never before reached, or boldly ventures away into the dim +recesses beyond the entrance to bring back hints of what may be known +and believed a hundred years hence, perhaps. The exact investigator +measures each stone. Patiently and toilsomely scientific men examine +them with glass and reagent. We need not do this, but we must omit none +of the stones. + +3. The work must be continuous. To continue the figure, the stones must +be considered in some regular order. One lesson in electricity, one in +sound, then one in some other department is injurious. We remember best +by associated facts, and, while with the child this is less so than with +the man, one great object of this work is to teach him to remember in +that way. + +4. Experiments should never be performed for mere show. Of two +experiments which illustrate a fact equally well it is often best to +select the most striking and brilliant one. The attention and interest +of the child will be gained in this way when they would not be to so +great an extent in any other. The point of the experiment, however, +should never be lost sight of in attention to the merely wonderful in +it. + +With older pupils, and especially with those who use books for +themselves and perform the experiments there considered, the fact that +experiments demand work, downright hard work, with care, and patience, +and perseverance, and courage, cannot be kept too prominently before +them. + +5. Every lesson should have a definite object. Not the general value of +the experiment, but some _one thing_ which it shows should be the object +considered. + +6. Each experiment should be associated with some truth expressed in +words. The experiment should be remembered in connection with a definite +statement in each case. The memory of either the experiment, or the +principle apart from the experiment, is a species of half knowledge +which should be avoided. An unillustrated principle must, when the +necessity arises, be stored in the memory; and in the systematic study +of books this necessity will often come. But we should never crowd this +abstract work on the memory unassisted by the suggestive concrete, when +the concrete aid is possible. + +7. All that is taught should be true. It is not necessary to attempt to +exhaust a subject, nor to attempt to teach minute details regarding it +to the pupils in our schools, but it is necessary that every statement +given to the pupil to be learned and remembered should contain no +element of falsehood. + +The student in mathematics experiences a feeling of growing strength and +power when he finds, in algebra, that the formula he used in arithmetic +in extracting a square root has grown in importance by leading +indirectly to a theorem of which it is only one particular case--a +theorem with a more definite proof, and a larger capability for use than +he had thought possible. When he finds a still simpler proof for the +binomial theorem in his study of the calculus, his feeling of increasing +power and the desire for still greater results deepens and intensifies. +Were he to find, on the contrary, that from a false notion of the means +to be used in making a thing simple, his teacher in arithmetic had +taught him what is false, we should approve his feeling of disgust and +disappointment. Early impressions are the most lasting, and the hardest +part of school work for the teacher is the unteaching of false ideas, +and the correcting of imperfectly formed and partially understood ideas. +I took a case from mathematics, the exact science, to illustrate this +point. But I must not neglect to notice the difference between that +subject and physical science. The latter consists of theories, +hypotheses, and so-called laws, supported by _observed facts_. The facts +remain, but time has overthrown many of the hypotheses and theories, and +it will doubtless overthrow more and give us something better and truer +in their place. While a careful distinction between what is known and +what is believed is necessary, I should always class the teaching of +accepted theories and hypotheses with the teaching of the true. + +But teachers, with more of imagination than good sense, teach +distinctions which do not exist, generalizations which do not +generalize, and do incalculable mischief by so doing. + +8. Experimental work should be thoroughly honest as to conditions and +results. If an experiment is not the success you expected it would be, +say so honestly, and if you know why, explain it. The pupil should be +taught to know just what _is_, theory or expectation to the contrary +notwithstanding. Discoveries in physical science have often originated +in a search for the reason for some unexpected thing. + +The relation of the study of science to books on science should be +considered. For the work done with pupils before they are given books to +use for themselves, any attempt to follow a text book is to be deplored. +The study of the properties of matter, for instance, would be a fearful +and wonderful thing to set a class of little ones at as a beginning in +scientific work. Just what matter, and force, and molecules, and atoms +are may be well enough for the student who is old enough to begin to use +a book, but they would be but dry husks to a younger child. Many of the +careful classifications and analyses of topics in text books had far +better be used as summaries than in any other way; and a definition is +better when the pupil knows it is true than when he is about to find out +whether it is or not. + +An ideal course in science would be one in which nothing should be +learned but that found out by the observation of the pupil himself under +the guidance of the teacher, necessary terms being given, but only when +the thing to be named had been considered, and the mind demanded the +term because of a felt need. Practically such a method is impossible in +its fullest sense, but a closer approach to it will be an advantage. + +Among the numerous good results which will follow the study of physical +science are the following: + +1. The cultivation of all the faculties of the child in a natural order, +thus making him grow into a ready, quick, and observing man. Education +in schools is too often shaped so as to repress instead of cultivate the +instinctive desire for the _knowledge of things_ which is found in every +child. + +2. The mechanical skill which comes from the preparation and use of +apparatus. + +3. The ability to follow directions. + +4. The belief in stated scientific facts, the understanding of +descriptions, diagrams, etc. + +5. The habitual scientific use of events which happen around us. + +6. The study of the old to find the new. The principle of the telephone, +for instance, is as old as spoken language. The mere[1] pulses in the +air--carrying all the characteristics of what you say--may set in +vibration either the drum of my ear, or a disk of metal. How simple--and +how simple all true science is--when we understand it. + +[Transcribers note 1: corrected from 'more'] + +8. The cultivation of the scientific judgment, and the inventive powers +of the mind. One great original investigator, made such by the direction +given his mind in one of our common schools, would be cheaply bought at +the price of all that the study of science in our schools will cost for +the next quarter of a century. + +8. Honesty. If there is a study whose every tendency is more in the +direction of honesty and truthfulness--both with ourselves and with +others--than is the study of experimental science, I do not know what it +is. + +Physical science, then, will help in making men and women out of our +boys and girls. It is worthy of a fair, earnest trial everywhere. + +A few minutes each day in which a class or a school study science in +some of the ways I have indicated will give a knowledge at the end of a +term or a year of no mean value. The time thus spent will have rested +the pupils from their books, to which they will return refreshed, and +instead of being time lost from other study the work will have been made +enough more earnest and intense to make it again. + +Apparatus for illustrating many of the ordinary facts of physics can be +devised from materials always at hand. Many more can be made by any +one skilled in the use of tools. In chemistry, the simplicity of the +apparatus, and comparative cheapness of ordinary chemicals, make the use +of a large number of beautiful and instructive experiments both easy and +cheap. + +A nation is what its trades and manufactures--its inventions and +discoveries--make it; and these depend on its trained scientific men. +Boys become men. Their growing minds are waiting for what I urge you +to offer. Science has never advanced without carrying practical +civilization with it--but it has never truly advanced save by the use of +the experimental method. _And it never will_. + +Let us then look forward to the time when our boys and young men--our +girls and young women--shall extend the boundaries of human knowledge by +its use, fitted so to do by what we may have done for them. + + * * * * * + + + + +GEOGRAPHICAL SOCIETY OF THE PACIFIC. + + +This society is a recent organization, the objects of which are to +encourage geographical exploration and discovery; to investigate and +disseminate geographical information by discussion, lectures, and +publications; to establish in this, the chief maritime city of the +Western States, for the benefit of commerce, navigation, and the +industrial and material interests of the Pacific slope, a place where +the means will be afforded of obtaining accurate information not only of +the countries bordering on the Pacific ocean, but of every part of the +habitable globe; to accumulate a library of the best books on geography, +history, and statistics; to make a collection of the most recent maps +and charts--especially those which relate to the Pacific coast, the +islands of the Pacific and the Pacific ocean--and to enter into +correspondence with scientific and learned societies whose objects +include or sympathize with geography. + +The society will publish a bulletin and an annual journal, which will +interchange with geographical and other societies. Monthly meetings are +to be held, at which original papers will be read or lectures be +given; and to which, as well as to the entertainments to distinguished +travelers, to the conversazioni, and to the informal evenings, the +fellows of the society will have the privilege of introducing their +friends. The initiation fee to the society is $10; monthly dues $1; life +fellowship $100. + +At a meeting held at the Palace Hotel on the 12th May, the following +gentlemen were elected for the ensuing year: President, Geo. Davidson; +Vice-Presidents, Hon. Ogden Hoffman, Wm. Lane Booker, H.B.M. Consul, and +John R. Jarboe; Foreign Corresponding Sec., Francis Berton; Home Cor. +Sec., James P. Cox; Treas., Gen. C. I. Hutchinson; Sec'y, C. Mitchell +Grant, F.R.G.S. The council is composed of the following: Hon. Joseph W. +Winans, Hon. J.F. Sullivan, Ralph C. Harrison, A.S. Hallidie, Thos. E. +Stevin, F.A.G.S., W.W. Crane, Jr., W.J. Shaw, C.P. Murphy, Thos. Brice, +Edward L.G. Steele, Gerrit L. Lansing, Joseph D. Redding. The Trustees +are Geo. Davidson, Wm. Lane Booker, Hon. Jno. S. Hager, Geo. Chismore, +M.D., Selim Franklin. + + * * * * * + + + + +THE BEHRING'S STRAITS CURRENTS. + + +It will be remembered that a short time since we mentioned the fact that +W.H. Dall, of the U. S. Coast Survey, who has passed a number of years +in Alaskan waters, on Coast Survey duty, denied the existence of any +branch of the Kuro Shiwo, or Japanese warm stream, in Behring's Straits. +That is, he failed to find evidence of the existence of any such +current, although he had made careful observations. At the islands in +Behring's Straits, his vessel had sailed in opposite directions with ebb +and flood tide, and he thought the only currents there were tidal in +their nature. The existence or non-existence of this current is an +important point in Arctic research on this side of the continent. + +At the last meeting of the Academy of Sciences, Prof. Davidson, of the +U. S. Coast Survey, author of the "Alaska Coast Pilot," refuted Dr. +Dall's opinion of the non-existence of a branch of the Kuro Shiwo, or +Japanese warm stream, from the north Pacific into the Arctic Ocean, +through Behring's Straits. He said that in 1857 he gave to the Academy +his own observations, and recently he had conferred with Capt. C.L. +Hooper, who commanded the U. S. steamer Thomas Corwin, employed as a +revenue steam cruiser in the Arctic and around the coast of Alaska. +Capt. Hooper confirms the opinions of all previous navigators, every one +of which, except Dr. Dall, say that a branch of this warm stream passed +northward into the Arctic through Behring's Strait. It is partly +deflected by St. Lawrence Island, and closely follows the coast on the +Alaskan side, while a cold current comes out south, past East Cape +in Siberia, skirting the Asiatic shore past Kamschatka, and thence +continues down the coast of China. He said ice often extended several +miles seaward, from East Cape on the Asiatic side of Behring Strait, +making what seamen call a false cape, and indicating cold water, while +no such formation makes off on the American side, where the water is +12 degrees warmer than on the Asiatic shore off the Diomede islands, +situated in the middle of Behring's Strait, the current varies in +intensity according to the wind. + +Frequently it is almost nothing for several days, when after a series of +southerly winds the shallow Arctic basin has been filled, under a heavy +pressure, with an unusual volume of water, and a sudden change to +northerly winds, makes even a small current setting southward for a few +days, just as at times the surface currents set out our Golden Gate +continuously for 24 and 48 hours, as shown by the United States Coast +Survey tide gauges. Whalers report that the incoming water then flows +in, under the temporary outflowing stream. + +Old trees, of a variety known to grow in tropical Japan, are floated +into the Arctic basin as far as past Point Barrow, on the American side, +but none are found on the Asiatic side, or near Wrangell Land, where a +cold stream exists, and ice remains late in the season. On the northern +side of the Aleutian islands are found cocoanut husks and other tropical +productions stranded along the beaches. The American coast of Alaska +has a much warmer climate than the Asiatic coast of Siberia, and the +American timber line extends very far north. The ice opens early in the +season on the American side, and invariably late on the Asiatic. + +Capt. C. L. Hooper says that when just north of Behring's Strait, off +the American coast, in the Arctic basin, the U.S. steamer Thomas Corwin, +when becalmed for 24 hours, drifted 40 miles to the northward. From +all these, and other facts, and the unanimous testimony of American +whalemen, who have for years spent many months annually in the Arctic, +and from his own observations, he argued that a branch of the Kuro-Shiwo +or Japanese warm stream, unquestionably runs northward through Behring's +Strait into the Arctic basin along the northwestern coast of Alaska. + +Prof. Davidson then called to mind the testimony in regard to the +existence of Plover Island, between Herald Island and Wrangell Land, +which he said was first made public through this academy. The evidence +of Capts. Williams and Thomas Long were recited and highly praised. One +of the officers of Admiral Rodgers' expedition climbed to near the top +of Herald Island, at a time of great refraction, when probably a false +horizon existed, and hence did not see Plover Island, although Wrangell +Land was in sight. + +Prof. Davidson thinks all the authorities are against Dr. Dall, who +attributes the warm current he observed on the American coast to water +from the Yukon River and to the large expanse of shallow water exposed +to the sun's rays. As Dall's observations only covered a few days of +possibly exceptional weather, and the whalers and Captain Hooper's cover +vastly longer periods, and whalers all say it is a pretty hard thing to +beat southward through Behring's Strait, owing to the northerly current +setting into the Arctic, we are forced to the conclusion that Dr. +Dall has mistaken the exception for the rule, and his conclusions are +therefore erroneous. When, in 1824, Wrangell went north, he, like +others, always found broken ice and considerable open water. In 1867, +when Capt. Thomas Long made his memorable survey of the coast of +Wrangell Land, the season was an exceptionally open one, and in +California we had heavy rains, extending into July. + + * * * * * + + + + +EXPERIMENTAL GEOLOGY. + +ARTIFICIAL PRODUCTION OF CALCAREOUS PISOLITES AND OOLITES. + + +Mr. Stanislas Meunier communicates to _Le Nature_ an account of some +interesting specimens of globular calcareous matter, resembling +pisolites or peastones both in appearance and structure, which were +accidentally formed as follows: The Northern Railway Company, France, +desiring to purify some calciferous water designed for use in steam +boilers, hit upon the ingenious expedient of treating it with lime water +whose concentration was calculated exactly from the amount of lime +held in the liquid to be purified. The liquids were mixed in a vast +reservoir, to which they were led by parallel pipes, and by which they +were given a rapid eddying motion. The transformation of the +bicarbonate into neutral carbonate of lime being thus effected with +the accompaniment of a circling motion, the insoluble salt which +precipitated, instead of being deposited in an amorphous state, hardened +into globules, the sizes of which were strictly regulated by the +velocity of the currents. Those that have been formed at one and the +same operation are uniform, but those formed at different times vary +greatly--their diameters varying by at least one millimeter to one and +a half centimeters. The surface of the smaller globules is smooth, but +that of the larger ones is rough. Even by the naked eye, it may be +seen that both the large and small globules are formed of regularly +superposed concentric layers. If an extremely thin section be made +through one of them it is found that the number of layers is very great +and that they are remarkably regular (A). By the microscope, it has been +ascertained that each layer is about 0.007 of a millimeter in thickness. + +On observing it under polarized light the calcareous substance is +discovered to be everywhere crystallized, and this suggests the question +whether the carbonate has here taken the form of aragonite or of +calcite. Examination has shown it to be the latter. The density of the +globules (2.58) is similar to that of ordinary varieties of calcite. It +is probable that if the operation were to take place under the influence +of heat, under the conditions above mentioned, aragonite would be +formed. It is hardly necessary to dwell upon the possible geological +applications of this mode of forming calcareous oolites and pisolites. + + +ON CRYSTALS OF ANHYDROUS LIME. + +Some time ago it was discovered that some limestone, which had been +submitted for eighteen months to a heat of nearly 1,000 degrees in +the smelting furnaces of Leroy-Descloges (France), had given rise to +perfectly crystallized anhydrous lime. Figure C shows three of these +crystals magnified 300 diameters. It will be noticed that they have a +striking analogy with grains of common salt. They are, in fact, cubes +(often imperfect), but do not polarize light, as a substance of the +first crystalline system should. However, it is rarely the case that the +crystals do not have _some_ action on light. Most usually, when the two +Nicol prisms are crossed so as to cause extinction, the crystals present +the appearance shown at D. That is to say, while the central portion +is totally inactive there are seen on the margins zones which greatly +brighten the light. + +[Illustration] + +A and B.--Calcareous Pisolites and Oolites produced artificially. +A.--External aspect and section of a Pisolite. B.--Details of internal +structure as seen by the microscope. + +C and D.--Crystals of anhydrous Lime obtained artificially. C.--Crystals +seen under the microscope in the natural light. D.--Crystals seen under +the microscope in polarized light. + +The phenomenon is explained by the slow carbonization of the anhydrous +lime under the influence of the air; the external layers passing to the +state of carbonate of lime or Iceland spar, which, as well known, has +great influence on polarized light. This transformation, which takes +place without disturbing the crystalline state, does not lead to any +general modification of the form of the crystals, and the final product +of carbonization is a cubic form known in mineralogical language as +_epigene_. As the molecule of spar is entirely different in form +from the molecule of lime, the form of the crystal is not absolutely +preserved, and there are observed on the edges of the epigene crystal +certain grooves which correspond with a loss of substance. These grooves +are quite visible, for example, on the crystal to the left in Fig. D. + +Up to the present time anhydrous lime has been known only in an +amorphous state. The experiment which has produced it in the form noted +above would doubtless give rise to crystallized states of other earthy +oxides likewise, and even of alkalino-earthy oxides. + + + + +COCCIDAE. + +[Footnote: A paper recently read before the California Academy of +Sciences.] + +By DR. H. BEHR. + + +With the exception of Hymenoptera there is no group of insects that +interfere in so many ways in good and evil with our own interests, as +that group of Homoptera called Coccidae. + +But while the Hymenoptera command our respect by an intellect that +approaches the human, the Coccus tribe possesses only the lowest kind of +instinct, and its females even pass the greater part of their lives in +a mere vegetation state, without the power of locomotion or perception, +like a plant, exhibiting only organs of assimilation and reproduction. + +But strange to say, these two groups, otherwise so very dissimilar, +exhibit again a resemblance in their product. Both produce honey and +wax. + +It is true, the honey of this tribe is almost exclusively used by the +ants. But I have tasted the honey-like secretion of an Australian +lecanium living; on the leaves of Eucalyptus dumosus; and the manna +mentioned in Scripture is considered the secretion of Coccus manniparus +(Ehrenberg) that feeds on a tamarix, and whose product is still used by +the native tribes round Mount Sinai. + +Several species of Coccides are used for the production of wax; many +more, among which the Cochenill, for dyes. + +All these substances can be obtained in other ways, even the Cochenill +is to a great extent superseded by aniline dyes, but in regard to one +production, indispensable to a great extent, we are entirely dependent +on some insects of this family; it is the Shellac, lately also found in +the desert regions around the Gila and Colorado on the Larrea Mexicana. +You will remember that excellent treatise on this variety of Shellac, +written by Professor J.M. Stillman at Berkeley, on its chemical +peculiarities. + +But all these different forms of utility fall very lightly in weight, +and can not even be counted as an extenuating circumstance, when we +compare them to the enormous evils brought on farmer and gardener by the +hosts of those Coccides that visit plantations, hothouses, and orchards. + +To combat successfully against these insect-pests we have first to study +their habits and then adapt to them our remedies, which you will see +are more effective when well administered than those which we possess +against insect pests of other classes. + +I give here only the outlines of their natural history, peculiarities +that are common to all, for it would be impossible to go into detail. +Where there are exceptions of practical importance I will mention them. + +In countries with a well defined winter the winged males appear as +soon as white frosts are no more usual, and copulate with the unwieldy +limbless female, that looks more like a gall or morbid excrescence, than +a living animal. Shortly after the young ones are perceptible near the +withered body of their mother, covered by waxy secretions that look +somewhat like a feathery down. + +These young ones are lively enough, they move about with agility, and +it is not till high summer that they fasten themselves permanently, and +lose feet and antennae, organs of locomotion and perception that are no +more of any use to them. (There is a slight difference in this regard +between different genera, as for instance, Coccus and Dorthesia retain +these organs in different degrees of imperfection, Lecanium and +Aspidiotus losing every trace of them.) + +In this limbless, senseless state the females remain fall and winter. +Toward the end of winter these animated galls begin to swell, and those +containing males enter the state of the chrysalis, from which the males +emerge at the beginning of the warm season and fecundate the gall-like +females, which undergo neither chrysalis state nor any other change, but +die, or we may call it dissolve into their offspring, for there scarcely +remains anything of them, except a pruinous kind of down, after having +given birth to the young ones. + +Now we come to the practical deduction from these facts. It is clear +that the only time when the scalebug can emigrate and infest a new +tree is the time when it is a larva, that is, when it has the power of +locomotion. In countries with a pronounced winter this time begins +much later than with us, but it ends about the same time, that is, the +beginning of August. I have seen the male of Aspidiotus in February, so +that the active larva may be expected in March, and the active Lecanium +Hesperidum I have seen last year, June 27, at Colonel Hooper's ranch in +Sonoma County. We may safely fix the time of the active scalebug from +March to August. + +Notwithstanding the agility of the young scalebug, the voyage from one +tree to another, considering the minute size of the traveler, is an +undertaking but seldom succeeding, but one female bug, if we take +into account its enormous fertility, is sufficient to cover with its +grandchildren next year a tree of moderate size. + +Besides there is another and much more effective way of transmigration +by the kind assistance of the ant who colonizes the scalebug as well for +its wax as it colonizes the Aphis for its honey. Birds on their feathers +and the gardener himself on his dress contribute to spread them. + +But even the ant can not transplant the scalebug when it is once firmly +fixed by its rostrum. + +It is evident, therefore, that the time for the application of +insecticides is the time when all the scalebugs are fixed, that is about +the end of July or beginning of August. All previous application will +clean the tree or plant only for a time, and does not prevent a more or +less numerous immigration from the neighboring vegetation, especially if +an ant-hill is not far off. + +As to the insecticide, there are to be applied two very effective ones, +each with its advantages and disadvantages. + +1. Petroleum and its different preparations. + +2. Lye or soap. + +The petroleum is the best disinfectant. It can safely be applied to any +cutting or stem, as long as it is not planted, but is one of the most +invidious substances when applied to vegetation in the garden, or +fields. If effectively applied, it can not be prevented from running +down the bark of the tree and entering the ground, where every drop +binds a certain amount of earth to an insoluble substance, in which +state it remains for ever. With every application the quantity of these +insoluble compounds is augmented and sterility added. + +If I am not mistaken, it was near Antwerp--at least I am certain it was +in Belgium--where the first experience of this kind is recorded. + +In France, preparations of coal tar have been recommended and have +been lately used in the form of a paint. May be that in this form the +substance is not so apt to enter into combinations with the soil. At any +rate, the method is of too recent a date to permit any conclusions about +the final result of these applications, as the invidious nature of the +substance produces, by gradual accumulation, its effects, which are not +perceived until they are irreparable. + +2. Lye or soap. The application of these insecticides requires more +care, and is therefore more troublesome. But instead of attracting +fertility from the soil, they add to it. In Southern Europe soap +and water has been for many years the remedy against the Lecanium +Hesperidum. The method applied by the farmers in Portugal, as described +to me by Dr. Bleasdale, is perhaps the most perfect one. The Portuguese +have very well observed that the colonization of scalebugs always begins +at the lowest end of the trunk and pretend, therefore, that the scalebug +comes out of the ground. This, of course, is not the case, but may their +interpretation be an error, they have been practical enough in utilizing +their observation about the invasion beginning near the roots. They +knead a ring of clay round the tree, in which ring the soap water runs +when they wash the tree, and besides, they fill frequently the little +ditch formed by this ring. + +This arrangement of course is only possible in climates of a rainy +summer. + +As it is our object to make our knowledge as available as possible for +practical purposes, I repeat for the benefit of cultivators the advice, +without repeating the reasoning: + +1. Use the petroleum for disinfecting imported trees and cuttings: + +2. Use soap for cleaning trees planted in your orchard. + +3. If you must use the petroleum in your garden, use it in August, when +a single application is sufficient. + + * * * * * + + + + +AGRICULTURAL ITEMS. + + +The exportation of dried apples from this country to France has greatly +increased of late years, and now it is said that a large part of this +useful product comes back in the shape of Normandy cider and light +claret. + +A.B. Goodsell says in the _New York Tribune_: "Put your hen feed around +the currants. I did this twice a week during May and June, and not a +currant worm was seen, while every leaf was eaten off other bushes 150 +feet distant, and not so treated." + +Buckwheat may be made profitable upon a piece of rough or newly cleared +ground: No other crop is so effective in mellowing rough, cloddy land. +The seed in northern localities should be sown before July 12; otherwise +early frosts may catch the crops. Grass and clover may sometimes be sown +successfully with buckwheat. + +The London News says: "Of all poultry breeding, the rearing of the goose +in favorable situations is said to be the least troublesome and most +profitable. It is not surprising, therefore, that the trade has of late +years been enormously developed. Geese will live, and, to a certain +extent, thrive on the coarsest of grasses." + +When a cow has a depraved appetite, and chews coarse, indigestible +things, or licks the ground, it indicates indigestion, and she should +have some physic. Give one pint and a half of linseed oil, one pound of +Epsom salts, and afterward give in some bran one ounce of salt and the +same of ground ginger twice a week. + +Asiatic breeds of fowl lay eggs from deep chocolate through every shade +of coffee color, while the Spanish, Hamburg, and Italian breeds are +known for the pure white of the eggshell. A cross, however remote, with +Asiatics, will cause even the last-named breeds to lay an egg slightly +tinted. + +In setting out currant bushes care should be exercised not to place any +buds under ground, or they will push out as so many suckers. Currants +are great feeders, and should be highly manured. To destroy the worm, +steep one table-spoonful of hellebore in a pint of water, and sprinkle +the bushes. Two or three sprinklings are sufficient for one season. + +Mr. Joseph Harris, of Rochester, makes a handy box for protecting melons +and cucumbers from insect enemies. Take two strips of board of the +required size, and fasten them together with a piece of muslin, so the +muslin will form the top and two sides of the box. Then stretch into +box form by inserting a small strip of wood as a brace between the two +boards. This makes a good, serviceable box, and, when done with for the +season, it can be packed into a very small space, by simply removing the +brace and bringing the two board sides together. As there is no patent +on the contrivance, anybody can make the boxes for himself. + +Mr. C. S. Read recently said before the London Fanners' Club: "American +agriculturists get up earlier, are better educated, breed their stock +more scientifically, use more machinery, and generally bring more +brains to bear upon their work than the English farmer. The practical +conclusion is, that if farmers in England worked hard, lived frugally, +were clad as meanly as those of the States, were content to drink filthy +tea three times a day, read more and hunted less, the majority of them +may continue to live in the old country."--_N. E. Farmer_. + + * * * * * + + + + +TIMBER TREES. + + +A paper was read by Sir R. Christison at the last meeting of the +Edinburgh Botanical Society upon the "Growth of Wood in 1880." In a +former paper, he said, he endeavored to show that, in the unfavorable +season of 1879, the growth of wood of all kinds of trees was materially +less than in the comparatively favorable season of 1878. He had now to +state results of measurements of the same trees for the recent favorable +season of 1880. The previous autumn was unfavorable for the ripening of +young wood, and the trees in an unprepared condition were exposed during +a great part of December, 1879, to an asperity of climate unprecedented +in this latitude. This might have led one to expect a falling off in the +growth of wood, and it appeared, from comparison of measurements, that, +with very few exceptions, the growth of wood last year was even more +below the average of favorable years than that of the bad year, 1879. +Thus, in fifteen leaf-shedding trees of various species, exclusive of +the oak, the average growth of trunk girth in three successive years +was: 1878, 8-10ths; 1879, 45-100ths; 1880, 3-10ths and a half. In +four specimens of the oak tribe, the growth was: 1878, 8-10ths; 1879, +77-100ths; 1880, 54-100ths. In twenty specimens of the evergreen +Pinaceae the growth was: 1878, 8-10ths; 1879, 7-10ths; 1880, 6-10ths and +a half. After giving details in regard to particular trees, Sir Robert +stated, as general deductions from his observations, that leaf-shedding +trees, exclusive of the oak, suffered most; that the evergreen Pinaceae +suffered least; and that there was some power of resistance on the part +of the oak tribe which was remarkable, the power of resistance of the +Hungary oak being particularly deserving of attention. In another +communication on the "extent of the season of growth," Sir Robert +stated, as the result of observations on five leaf-shedding and five +evergreen trees, that in the case of the former, even in a fine year, +the growth of wood was confined very nearly, if not entirely, to the +months of June, July, and August; while in the case of the latter growth +commenced a month sooner, terminating, however, about the same time. Mr. +A. Buchan said it was proposed that the inquiry should be taken up more +extensively over Scotland. + + * * * * * + +MEDICAL USES OF FIGS.--Prof. Bouchut speaks (_Comptes Rendus_) of some +experiments he has made, going to show that the milky juice of the +fig-tree possesses a digestive power. He also observed that, when some +of this preparation was mixed with animal tissue, it preserved it +it from decay for a long time. This fact, in connection with Prof. +Billroth's case of cancer of the breast, which was so excessively foul +smelling that all his deodorizers failed, but which, on applying a +poultice made of dried figs cooked in milk, the previously unbearable +odor was entirely done away with, gives an importance to this homely +remedy not to be denied.--_Medical Press and Circ._ + + * * * * * + + + + +BLOOD RAIN. + + +The sensibilities of ignorant or superstitious people have at various +times been alarmed by the different phenomena of so-called blood, ink, +or sulphur rains. Ehrenberg very patiently collected records of the most +prominent instances of these, and published them in his treatise on the +dust of trade winds. Some, it is known, are due to soot; others, to +pollen of conifers or willows; others, to the production of fungi and +algae. + +Many of the tales of the descent of showers of blood from the clouds +which are so common in old chronicles, depends, says Mr. Berkeley, the +mycologist, upon the multitudinous production of infusorial insects or +some of the lower algae. To this category belongs the phenomenon known +under the name of "red snow." One of the most peculiar and remarkable +form, which is apparently virulent only in very hot seasons, is caused +by the rapid production of little blood-red spots on cooked vegetables +or decaying fungi, so that provisions which were dressed only the +previous day are covered with a bright scarlet coat, which sometimes +penetrates deeply into their substance. This depends upon the growth of +a little plant which has been referred to the algae, under the name +of _Palmellae prodigiosa_. The rapidity with which this little plant +spreads over meat and vegetables is quite astonishing, making them +appear precisely as if spotted with arterial blood; and what increases +the illusion is, that there are little detached specks, exactly as if +they had been squirted from a small artery. The particles of which the +substance is composed have an active molecular motion, but the morphosis +of the production has not yet been properly observed. The color of the +so-called "blood rain" is so beautiful that attempts have been made +to use it as a dye, and with some success; and could the plant be +reproduced with any constancy, there seems little doubt that the color +would stand. On the same paste with the "blood-rain" there have been +observed white, blue, and yellow spots, which were not distinguishable +in structure and character. + + * * * * * + + + + +TOPICAL MEDICATION IN PHTHISIS. + + +Dr. G.H. Mackenzie reports in the _Lancet_ an acute case of phthisis +which was successfully treated by him by causing the patient to respire +as continuously as possible, through a respirator devised for the +purpose, an antiseptic atmosphere. The result obtained appears to bear +out the experiments of Schueller of Greifswald, who found that animals +rendered artificially tuberculous were cured by being made to inhale +creosote water for lengthened periods. Intermittent spraying or inhaling +does not produce the same result. In order to insure success the +application to the lungs must be made _continuously_. For this purpose +Dr. Mackenzie has used various volatile antiseptics, such as creosote, +carbolic acid, and thymol. The latter, however, he has discarded +as being too irritating and inefficient. Carbolic acid seems to be +absorbed, for it has been detected freely in the urine after it had been +inhaled; but this does not happen with creosote. As absorption of the +particular drug employed is not necessary, and therefore not to be +desired, Dr. Mackenzie now uses creosote only, either pure or dissolved +in one to three parts of rectified spirits. "Whether," says he, "the +success so far attained is due to the antidotal action of creosote and +carbolic acid on a specific tubercular neoplasm, or to their action as +preventives of septic poisoning from the local center in the lungs, +it is certain that their continuous, steady use in the manner just +described has a decidedly curative action in acute phthisis, and is +therefore, worthy of an extended trial." + + * * * * * + + + + +ON THE LAW OF AVOGADRO AND AMPERE. + + +The Scientific American Supplement of May 14,1881, contains, under this +head, Mr. Wm. H. Greene's objections to my demonstration (in No. 270 +of the same paper) of the error of Avogadro's hypothesis. The most +important part of my argument is based on the evidence afforded by the +compound cyanogen; and Mr. Greene, directing his attention to this +subject in the first place, states that because cyanogen combines +with hydrogen or with chlorine, without diminution of volumes, I have +concluded that the hypothesis falls to the ground. This statement has +impressed me with the conviction that Mr. Greene has failed to perceive +the difficulty which is at the bottom of the question, and I will, +therefore, present the subject more fully and comprehensively. + +The molecule of any elementary body is, on the ground of the hypothesis, +assumed to be a compound of two atoms, and the molecule of carbon +consequently C_2=24; that of nitrogen N_2=28. Combination of the two, +according to the same hypothesis, takes place by substitution; the +atoms are supposed to be set free and to exchange places, forming a +new compound different from the original only in this: that each new +particle contains an atom of each of the two different substances, while +each original particle consists of two identical atoms. The product is, +therefore, assumed to be, and can, under the circumstances, be no other +than particles of the composition CN and weight 26. These particles are +molecules, according to the definition laid down, just as C_2 and N_2; +but there is this essential difference, that the specific gravity of +cyanogen gas, 26, coincides with the molecular weight, while the assumed +molecular weight, N_2=28, is twice as great as the specific gravity of +the gas, N=14. + +In using the term molecular weight, it is to be remembered that it does +not express the weight of single molecules, but only their relative +weight, millions of millions molecules being contained in the unit of +volume. But on the hypothesis that there is the same number of molecules +in the same volume of any gas, the specific gravities of gases can be, +and are, identified with their molecular weights, and, on the ground of +the hypothesis again, the unit of the numbers which enter into every +chemical reaction and constitute the molecular weight, is stipulated to +be that contained in two volumes. + +The impossibility of the correctness of the hypothesis is now revealed +by the fact just demonstrated, that in the case of nitrogen the specific +gravity does not coincide with the molecular weight. If equal volumes +contain the same number of molecules, the specific gravities and the +molecular weights must be the same; and if the specific gravities and +molecular weights are not the same, equal volumes cannot contain the +same number of molecules. The assumed molecular weight of nitrogen is +twice as great as the specific gravity, but the molecular weight and +the specific gravity of cyanogen are identical; the number of molecules +contained in one volume of cyanogen must, therefore, necessarily be +twice as great as the number contained in one of nitrogen, and this is +fully and completely borne out by the chemical facts. + +In saying that when cyanogen combines with chlorine there is naturally +no condensation, Mr. Greene has no idea that this natural law is fatal +to his artificial law of Avogadro and Ampere; "for," continues he, "the +theory is fulfilled by the actual reaction." It is not. The theory +requires two vols. of cyanogen and two vols. of chlorine, that is, the +unit of numbers, to enter into reaction and to produce two vols. of +the compound. But they produce four vols., and the non-condensation is +therefore in opposition to the theory. It is true beyond doubt that the +molecular weight of cyanogen chloride is contained in two volumes, in +spite of the hypothesis, not on the ground of it; two vols. + two vols., +producing four vols.; two vols. could, theoretically, contain only half +the unit of numbers, and there seems to be no escape from the following +general conclusions: + +1. Two vols. of CNCl, representing the unit of numbers, the constituent +weights, C=12, N=14, Cl=35.5, must each, likewise, represent the same +number; the molecular weight is, therefore, contained in one vol. of N +or Cl, but in two of CNCl and equal numbers are not contained in equal +volumes. + +2. The weights N=14, Cl=35.5 occupy in the free state one volume, but +in the combination, CNCl, two volumes; their specific gravity is, +therefore, by chemical action reduced to one half. The fact thus +elicited of the variability and variation of the specific gravity is of +fundamental importance and involves the irrelevancy of the mathematical +demonstration of the hypothesis. In this demonstration the specific +gravity is assumed to be constant, and this assumption not holding good, +and the number of molecules in unit of volume being reduced to one half +when the specific gravity is reduced to the same extent by chemical +action, it is obvious that the mathematical proof must fail. Mr. Greene +states that I have proceeded to demolish C. Clerk Maxwell's conclusion +from mathematical reasoning. This is incorrect; I have found no fault +with the conclusion of the celebrated mathematician, and consider his +reasoning unimpeachable. I am also of opinion that he is entitled to +great credit and respect for the prominent part he has taken in the +development of the kinetic theory, and further think that it was for +the chemists to produce the fact of the variability of the specific +gravities, which they would probably not have failed to do but for the +prevalence of Avogadro's hypothesis, which is virtually the assertion of +the constancy of the specific gravities. + +3. The unit of numbers being represented by Cl=35.5, it is likewise +represented by H=1, and as the product of the union of the two elements +is HCl, 36.5 = two vols., combination takes place by addition and not by +substitution; consequently are + +4. The elementary molecules not compounds of atoms? And the distinction +between atoms and molecules is an artificial one, not justified by the +natural facts. + +5. Is the molecular weight not in every instance = two volumes? + +These conclusions overthrow all the fundamental assumptions on which the +hypothesis rests, and leave it, in the full meaning of the term, without +support. Though Mr. Greene states that my arguments are based upon +entirely erroneous premises, he has not even attempted to invalidate a +single one of my premises. + +As he considers the non-condensation to be natural in the case of +cyanogen and chlorine, the condensation of two vols. of HCl + two vols. +of H_3N to two vols. of NH_4Cl ought to appear to him unnatural. He, +however, contends for it, and tries, on this solitary occasion, to +strengthen his opinion by authority, though the proof, if it could be +given, that ammonium chloride at the temperature of volatilization is +decomposed into its two constituents, would be insufficient to uphold +the theory. + +The ground on which Mr. Greene assumes a partial decomposition at 350 deg. +C. is the slight excess of the observed density (14.43) over that +corresponding to four vols. (13.375). There is, however, a similar +slight excess in the case of the vapor of ammonium cyanide, the same +values being respectively 11.4 and 11; and as this compound is volatile +at 100 deg. C and, at the same time, is capable to exist at a very high +temperature, being formed by the union of carbon with ammonia, nobody +has ever, as far as I am aware, maintained that it is completely or +partially decomposed at volatilization. The excess of weight not being +due, therefore, to such cause in this case, it cannot be due to it in +the other. + +The question being whether the molecular weight of ammonium chloride +is two vols. or four vols., an idea of the magnitude of the assumed +decomposition is conveyed by the proportion of the volume of the +decomposed salt to the volume of the non-decomposed, and Mr. Greene's +quotation of the percentage of weight is irrelevant and misleading, and +his number not even correct. A mixture containing + + 1.055 vols. of spec. gr. 26.75 = 28.22 and + 12.32 " " " " 13.375 = 164.78 + ------ ------ + 13.375 " 193 + +has the spec. gr. 193 / 13.375 = 14.43. The proportion in one vol. of +the undecomposed to the decomposed salt is, therefore, as 1 to 11.68 and +the percentage of volume of the former 0.0789, and that of weight 28.22 +/ 193 = 0.146, and not 0.16. + +It is not easy to imagine why a small fraction of the heavy molecules +should be volatilized undecomposed, the temperature being sufficient +to decompose the great bulk. Marignac assumes, indeed, partial +decomposition, but the difficulties which he encountered in making the +experiments, on the results of which his opinion rests, were so great +that he himself accords to the numbers obtained by him only the value of +a rough approximation. + +The heat absorbed in volatilization will comprise the heat of +combination as well as of aggregation, if decomposition takes place, and +will therefore be the same as that set free at combination. Favre and +Silbermann found this to be 743.5 at ordinary temperature, from which +Marignac concludes that it would be 715 for the temperature 350 deg.; he +found as the heat of volatilization 706, but considers the probable +exact value to be between 617 and 818.[1] + +[Footnote 1: See _Comptes Rendus_, t. lxvii., p. 877.] + +An uncertainty within so wide a range does not justify the confidence +of Mr. Greene which he expresses in these words: "It is, therefore, +extremely probable that ammonium chloride is almost entirely +dissociated, even at the temperature of volatilization." By Boettinger's +apparatus a decomposition may possibly have been demonstrated, but it +remains to be seen whether it is not due to some special cause. + +When Mr. Greene says that the relations between the physical properties +of solids and liquids and their molecular composition can in no +manner affect the laws of gases, nobody is likely to dissent; but the +conclusion that their discussion is foreign to the question of the +number of molecules in unit of volume does by no means follow. If the +specific gravity of a solid or the weight of unit of volume represents +a certain number of molecules, and is found to occupy two volumes in a +compound of the solid with another solid, the number of molecules in one +volume is reduced to one half. This I have shown to be the case in a +number of compounds, and the decrease of the specific gravity with +increase of the complexity of composition appears to be a general law, +as may be concluded from the very low specific gravity of the most +highly organized compounds, for instance the fatty bodies, the molecules +of which, being composed of very many constituents, are of heavy weight; +and likewise the compounds which occur in combination with water and +without it, the simpler compound having invariably a greater specific +gravity than the one combined with water; for instance: + + BaH_2O_2 sp. gr. 4.495 + " " + 8H_2O " 1.656 + S_2H_2O_2 " 3.625 + " " + 8H_2O " 1.396 + FeSO_4 " 3.138 + " + 7H_2O " 1.857 + +and so in every other case. This is now a recurrence of what takes +place in gases, and proves the fallacy of the hypothesis; for if these +compounds could be volatilized the vapor densities would necessarily +vary in the inverse proportion of the degree of composition. + +The reproach that Berthelot has been endeavoring for nearly a quarter of +a century to hold back the progress of scientific chemistry, is a great +and unjustifiable misrepresentation of the distinguished chemist +and member of the Institute of France, who has done so much for +thermo-chemistry, and the more unfortunate as it seems to serve only the +purpose of a prelude to the following sentences: "But Mr. Vogel cannot +claim, as can Mr. Berthelot, any real work or experiment, however +roughly performed, suggested by the desire to prove the truth of his +own views. Let him not, then, bring forth old and long since explained +discrepancies, ... but when he will have discovered new or overlooked +facts ... chemists will gladly listen." ... Mr. Greene is here no longer +occupied to investigate whether what I have said concerning Avogadro's +hypothesis is true or false, but with myself he has become personal, and +in noticing his remarks my sole object is to contend against an error +which is much prevalent. If, according to Mr. Greene, the real work of +science consists in experimenting, and conclusions unsupported by our +own experiments have no value, it does not appear for what purpose he +has published his answer to my paper; an experiment of his, settling +Marignac's uncertain results, would have justified the reliance he +places on them. The ground he takes is utterly untenable. Experiments +are necessary to establish facts; without them there could be no +science, and the highest credit is due to those who perform successfully +difficult or costly experiments. Experimenting is, however, not the +aim and object of science, but the means to arrive at the truth; and +discoveries derived from accumulated and generally accepted facts are +not the less valuable on account of not having been derived from new and +special experiment. + +It is, further, far from true that the real work of science consists +in experimenting; mental work is not less required, and the greatest +results have not been obtained by experimenters, but by the mental labor +of those who have, from the study of established facts, arrived at +conclusions which the experimenters had failed to draw. This is +naturally so, because a great generalization must explain all the facts +involved, and can be derived only from their study; but the attention +of the experimenter is necessarily absorbed by the special work he +undertakes. I refer to the three greatest events in science: the +discovery of the Copernican system, the three laws of Kepler, and +Newton's law of gravitation, none of which is due to direct and special +experimentation. Copernicus was an astronomer, but the discovery of his +system is due chiefly to his study of the complications of the Ptolemaic +system. Kepler is a memorable witness of what can be accomplished by +skillful and persistent mental labor. "His discoveries were secrets +extorted from nature by the most profound and laborious research." The +discovery of his third law is said to have occupied him seventeen years. +Newton's great discovery is likewise the result of mental labor; he was +enabled to accomplish it by means of the laws of Kepler, the laws of +falling bodies established by Galileo, and Picard's exact measurement of +a degree of a meridian. + +If, then, mental work is as indispensable as experimental, it is not +less true that there are men more specially fitted for the one, others +for the other, and the best interests of science will be served when +experiments are made by those specially adapted, skillful, and favorably +situated, and the possibly greatest number of men, able and willing to +do mental work, engage in extracting from the accumulated treasures of +experimental science all the results which they are capable to yield. +Any truth discovered by this means is clear gain, and saves the waste +of time, labor, and money spent in unnecessary experiment. Mr. Greene's +zeal for experiment and depreciation of mental work would be in order, +if ways and means were to be found to render the advancement of science +as difficult and slow as possible; they are decidedly not in the +interest of science, and can not have been inspired by a desire for its +promotion. + +As the evidence of the specific heats of the fallacy of Avogadro's +hypothesis involves lengthy explanations, the subject is reserved for +another paper. + +San Francisco, Cal., May, 1881. + +E. VOGEL. + + * * * * * + + + + +DYEING REDS WITH ARTIFICIAL ALIZARIN. + +By M. MAURICE PRUD'HOMME. + + +Since several years, the methods of madder dyeing have undergone a +complete revolution, the origin of which we will seek to point out. When +artificial alizarin, thanks to the beautiful researches of Graebe and +Liebermann, made its industrial appearance in 1869, it was soon found +that the commercial product, though yielding beautiful purples, was +incapable of producing brilliant reds (C. Koechlin). While admitting +that the new product was identical with the alizarin extracted from +madder, we were led to conclude that in order to produce fine Turkey +reds, the coloring matters which accompany alizarin must play an +important part. This was the idea propounded by Kuhlmann as far back as +1828 (_Soc. Ind. de Mulhouse_, 49, p. 86). According to the researches +of MM. Schuetzenberger and Schiffert, the coloring matters of madder +are alizarin, purpurin, pseudopurpurin, purpuroxanthin, and an orange +matter, which M. Rosenstiehl considers identical with hydrated purpurin. +Subsequently, there have been added to the list an orange body, +purpuroxantho-carbonic acid of Schunck and Roemer, identical with the +munjistin found by Stenhouse in the madder of India. It was known +that purpuroxanthin does not dye; that pseudopurpurin is very easily +transformed into purpurin, and the uncertainty which was felt concerning +hydrated purpurin left room merely for the hypothesis that Turkey-red +is obtained by the concurrent action of alizarin and purpurin. In the +meantime, the manufacture of artificial alizarin became extended, and a +compound was sold as "alizarin for reds." It is now known, thanks to the +researches of Perkin, Schunck, Roemer, Graebe, and Liebermann, that in +the manufacture of artificial alizarin there are produced three distinct +coloring matters--alizarin, iso or anthrapurpurin, and flavopurpurin, +the two latter being isomers of purpurin. We may remark that purpurin +has not been obtained by direct synthesis. M. de Lalande has produced +it by the oxidation of alizarin. Alizarin is derived from +monosulphanthraquinonic acid, on melting with the hydrate of potassa or +soda. It is a dioxyanthraquinone. + +Anthrapurpurin and flavopurpurin are obtained from two isomeric +disulphanthraquinonic acids, improperly named isoanthraflavic and +anthraflavic acids, which are converted into anthrapurpurin and +flavopurpurin by a more profound action of potassa. These two bodies are +trioxyanthraquinones. + +We call to mind that alizarin dyes reds of a violet tone, free from +yellow; roses with a blue cast and beautiful purples. Anthrapurpurin and +flavopurpurin differ little from each other, though the shades dyed +with the latter are more yellow. The reds produced with these coloring +matters have a very bright yellowish reflection, but the roses are too +yellow and the purples incline to a dull gray. + +Experience with the madder colors shows that a mixture of alizarin and +purpurin yields the most beautiful roses in the steam style, but it is +not the same in dyeing, where the roses got with fleur de garance have +never been equaled. + +"Alizarins for reds" all contain more or less of alizarin properly +so-called, from 1 to 10 per cent., along with anthrapurpurin and +flavopurpurin. This proportion does not affect the tone of the reds +obtained further than by preventing them by having too yellow a tone. + +The first use of the alizarins for reds was for application of styles, +that is colors containing at once the mordant and the coloring matter +and fixed upon the cloth by the action of steam. Good steam-reds were +easily obtained by using receipts originally designed for extracts of +madder (mixtures of alizarin and purpurin). On the other hand, the first +attempts at dyeing red grounds and red pieces were not successful. The +custom of dyeing up to a brown with fleur and then lightening the shade +by a succession of soapings and cleanings had much to do with this +failure. Goods, mordanted with alumina and dyed with alizarin for reds +up to saturation, never reach the brown tone given by fleur or garancin. +This tone is due in great part to the presence of fawn colored matters, +which the cleanings and soapings served to destroy or remove. The same +operations have also another end--to transform the purpurin into its +hydrate, which is brighter and more solid. The shade, in a word, loses +in depth and gains in brightness. With alizarins for reds, the case is +quite different; they contain no impurities to remove and no bodies +which may gain brightness in consequence of chemical changes under the +influence of the clearings and soapings. These have only one result, in +addition to the formation of a lake of fatty acid, that is to make the +shades lose in intensity. The method of subjecting reds got up with +alizarin to the same treatment as madder-reds was faulty. + +There appeared next a method of dyeing bases upon different +principles. The work of M. Schuetzenberger (1864) speaks of the use of +sulpho-conjugated fatty acids for the fixation of aniline colors. In +England, for a number of years, dyed-reds had been padded in soap-baths +and afterwards steamed to brighten the red. In 1867, Braun and Cordier, +of Rouen, exhibited Turkey reds dyed in five days. The pieces were +passed through aluminate of soda at 18 deg. B., then through ammonium +chloride, washed, dyed with garancin, taken through an oil-bath, dried +and steamed for an hour, and were finally cleared in the ordinary manner +for Turkey-reds. The oil-bath was prepared by treating olive-oil with +nitric acid. This preparation, invented by Hirn, was applied since 1846 +by Braun (Braun and Cordier). Since 1849, Gros, Roman, and Marozeau, +of Wesserling, printed fine furniture styles by block upon pieces +previously taken through sulpholeic acid. When the pieces were steamed +and washed the reds and roses were superior to the old dyed reds and +roses produced at the cost of many sourings and soapings. Certain makers +of aniline colors sold mixtures ready prepared for printing which were +known to contain sulpholeic acids. There was thus an idea in the air +that sulpholeic acid, under the influence of steam, formed brilliant and +solid lakes with coloring matters. These facts detract in nothing from +the merit of M. Horace Koechlin, who combined these scattered data +into a true discovery. The original process may be summed up under the +following heads: Printing or padding with an aluminous mordant, which is +fixed and cleaned in the usual manner; dyeing in alizarin for reds with +addition of calcium acetate; padding in sulpholeic acid and drying; +steaming and soaping. The process was next introduced into England, +whence it returned with the following modifications; in place of +olive-oil or oleic acid, castor oil was used, as cheaper, and the number +of operations was reduced. Castor oil, modified by sulphuric acid, can +be introduced at once into the dye-beck, so that the fixation of the +coloring matter as the lake of a fatty acid is effected in a single +operation. The dyeing was then followed by steaming and soaping. + +For red on white grounds and for red grounds, a mordant of red liquor at +5 deg. to 6 deg. B. is printed on, with a little salt of tin or nitro-muriate of +tin. It is fixed by oxidation at 30 deg. to 35 deg. C., and dunged with cow-dung +and chalk. The pieces are then dyed with 1 part alizarin for reds at 10 +per cent., 1/4 to 1/2 oil for reds (containing 50 per cent.), 1-6th part +acetate of lime at 15 deg. B., giving an hour at 70 deg. and half an hour at the +same heat. Wash, pad in oil (50 to 100 grms. per liter of water), dry on +the drum, or better, in the hot flue, and steam for three-quarters to an +hour and a half. The padding in oil is needless, if sufficient oil has +been used in dyeing, and the pieces may be at once dried and steamed. +Wash and soap for three-quarters of an hour at 60 deg.. Give a second +soaping if necessary. If there is no fear of soiling the whites, dye at +a boil for the last half-hour, which is in part equal to steaming. + +Red pieces and yarns may be dyed by the process just given for red +grounds; or, prepare in neutral red oil, in the proportion of 150 grms. +per liter of water for pieces and 15 kilos for 100 kilos of yarns. For +pieces, pad with an ordinary machine with rollers covered with +calico. Dry the pieces in the drum, and the yarn in the stove. Steam +three-quarters of an hour at 11/2 atmosphere. Mordant in pyrolignite of +alumina at 10 deg. B., and wash thoroughly. Dye for an hour at 70 deg., and half +an hour longer at the same heat, using for 100 kilos of cloth or yarn 20 +kilos alizarin at 10 per cent., 10 kilos acetate of lime at 18 deg. B., and +5 kilos sulpholeic acid. Steam for an hour. Soap for a longer or shorter +time, with or without the addition of soda crystals. There may be added +to the aluminous mordant a little salt of tin to raise the tone. Lastly, +aluminate of soda may be used as a mordant in place of red liquor or +sulphate of alumina. + +Certain firms employ a so-called continuous process. The pieces are +passed into a cistern 6 meters long and fitted with rollers. This +dye-bath contains, from 3 to 5 grms. of alizarin per liter of water, and +is heated to 98 deg.. The pieces take 5 minutes to traverse this cistern, +and, owing to the high temperature and the concentration of the dye +liquor, they come out perfectly dyed. Two pieces may even be passed +through at once, one above the other. As the dye-bath becomes exhausted, +it must be recruited from time to time with fresh quantities of +alizarin. The great advantage of this method is that it economizes not +merely time but coloring matter. + +The quantity of acetate of lime to be employed in dyeing varies with the +composition of the mordant and with that of the water. Schlumberger has +shown that Turkey-red contains 4 molecules of alumina to 3 of lime. +Rosenstiehl has shown that alumina mordants are properly saturated if +two equivalents of lime are used for each equivalent of alizarin, if the +dyeing is done without oil. These figures require to be modified when +the oil is put into the dye beck, as it precipitates the lime. Acetate +of lime at 15 deg. B., obtained by saturating acetic acid with chalk and +adding a slight excess of acetic acid, contains about 1/4 mol. acetate of +lime.--_Bulletin de la Societe Chimique de Paris._ + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +Sent by mail, postage prepaid, to subscribers in any part of the United +States or Canada. Six dollars a year, sent, prepaid, to any foreign +country. + +All the back numbers of THE SUPPLEMENT, from the commencement, January +1, 1876, can be had. 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You can also find out about how to make a +donation to Project Gutenberg, and how to get involved. + + +**Welcome To The World of Free Plain Vanilla Electronic Texts** + +**eBooks Readable By Both Humans and By Computers, Since 1971** + +*****These eBooks Were Prepared By Thousands of Volunteers!***** + + +Title: Scientific American Supplement, No. 286 + June 25, 1881 + +Author: Various + +Release Date: June, 2005 [EBook #8297] +[Yes, we are more than one year ahead of schedule] +[This file was first posted on July 4, 2003] + +Edition: 10 + +Language: English + +Character set encoding: ISO-Latin-1 + +*** START OF THE PROJECT GUTENBERG EBOOK SCIENTIFIC AMERICAN NO. 286 *** + + + + +Produced by Olaf Voss, Don Kretz, Juliet Sutherland, +Charles Franks and the Online Distributed Proofreading Team. + + + + +[Illustration] + + + + +SCIENTIFIC AMERICAN SUPPLEMENT NO. 286 + + + + +NEW YORK, JUNE 25, 1881 + +Scientific American Supplement. Vol. XI, No. 286. + +Scientific American established 1845 + +Scientific American Supplement, $5 a year. + +Scientific American and Supplement, $7 a year. + + + * * * * * + + TABLE OF CONTENTS. + +I. ENGINEERING AND MECHANICS.--One Thousand Horse Power Corliss Engine. + 5 figures, to scale, illustrating the construction of the new one + thousand horse power Corliss engine, by Hitch, Hargreaves & Co. + + Opening of the New Workshop of the Stevens Institute of Technology. + Speech of Prof. R.W. Raymond, speech of Mr. Horatio Allen. + + Light Steam Engine for Aeronautical Purposes. Constructed for Capt. + Mojoisky, of the Russian Navy. + + Complete Prevention of Incrustation in Boilers. Arrangement for + purifying boiler water with lime and carbonate of soda.--The + purification of the water.--Examination of the purified + water.--Results of water purification. + + Eddystone Lighthouse. Progress of the work. + + Rolling Mill for Making Corrugated Iron. 1 figure. The new mill of + Schultz, Knaudt & Co., of Essen, Germany. + + Railway Turntable in the Time of Louis XIV. 1 figure. Pleasure car. + Railway and turntable at Mary-le-Roy Chateau, France, in 1714. + + New Signal Wire Compensator. Communication from A. Lyle, describing + compensators in use on the Nizam State Railway, East India. + + Tangye's Hydraulic Hoist. 2 figures. + + Power Loom for Delicate Fabrics. 1 figure. + + How Veneering is Made. + +II. TECHNOLOGY AND CHEMISTRY.--The Constituent Parts of Leather. The + composition of different leathers exhibited at the Paris + Exhibition.--Amount of leather produced by different tonnages of 100 + pounds of hides.--Percentage of tannin absorbed under different + methods of tanning.--Amounts of gelatine and tannin in leather of + different tonnages, etc. + + Progress in American Pottery. + + Photographic Notes.--Mr. Waruerke's New Discovery.--Method of + converting negatives directly into positives.--Experiments of Capt. + Bing on the sensitiveness of coal oil--Bitumen plates.--Method of + topographic engraving. By Commandant DE LA NOE.--Succinate of Iron + Developer.--Method of making friable hydro-cellulose. + + Photo-Tracings in Black and Color. + + Dyeing Reds with Artificial Alizarin. By M. MAURICE PRUD'HOMME. + +III. ELECTRICITY, PHYSICAL SCIENCE, ETC.--On Faure's Secondary Battery. + + Physical Science in Our Common Schools.--An exceptionally strong + argument for the teaching of physical science by the experimental + method in elementary schools, with an outline of the method and the + results of such teaching. + + On the Law of Avogadro and Ampere. By E. VOGEL. + +IV. GEOGRAPHY, GEOLOGY, ETC.--Petroleum and Coal in Venezuela. + + Geographical Society of the Pacific. + + The Behring's Straits Currents.--Proofs of their existence. + + Experimental Geology.--Artificial production of calcareous pisolites + and oolites.--On crystals of anhydrous lime.--4 figures. + +V. NATURAL HISTORY, ETC.--Coccidæ. By Dr. H. BEHR.--An important paper + read before the California Academy of Sciences.--The marvelous + fecundity of scale bugs.--Their uses.--Their ravages.--Methods of + destroying them. + + Agricultural Items. + + Timber Trees. + + Blood Rains. + +VI. MEDICINE AND HYGIENE.--Medical Uses of Figs. + + Topical Medication in Phthisis. + +VII. ARCHITECTURE, ETC.--Suggestions in Architecture.--Large + illustration.--The New High School for Girls, Oxford, England. + + * * * * * + + + + +PETROLEUM AND COAL IN VENEZUELA. + + +MR. E. H. PLUMACHER, U. S. Consul at Maracaibo, sends to the State +Department the following information touching the wealth of coal and +petroleum probable in Venezuela: + +The asphalt mines and petroleum fountains are most abundant in that part +of the country lying between the River Zulia and the River Catatumbo, +and the Cordilleras. The wonderful sand-bank is about seven kilometers +from the confluence of the Rivers Tara and Sardinarte. It is ten meters +high and thirty meters long. On its surface can be seen several round +holes, out of which rises the petroleum and water with a noise like that +made by steam vessels when blowing off steam, and above there ascends a +column of vapor. There is a dense forest around this sand-bank, and the +place has been called "El Inferno." Dr. Edward McGregor visited the +sand-bank, and reported to the Government that by experiment he had +ascertained that one of the fountains spurted petroleum and water at the +rate of 240 gallons per hour. Mr. Plumacher says that the petroleum is +of very good quality, its density being that which the British market +requires in petroleum imported from the United States. The river, up to +the junction of the Tara and Sardinarte, is navigable during the entire +year for flat-bottomed craft of forty or fifty tons. + +Mr. Plumacher has been unable to discover that there are any deposits +of asphalt or petroleum in the upper part of the Department of Colon, +beyond the Zulia, but he has been told that the valleys of Cucuta and +the territories of the State of Tachira abound in coal mines. There are +coal mines near San Antonia, in a ravine called "La Carbonera," and +these supply coal for the smiths' forges in that place. Coal and asphalt +are also found in large quantities in the Department of Sucre. Mr. +Plumacher has seen, while residing in the State of Zulia, but one true +specimen of "lignite," which was given to him by a rich land-owner, +who is a Spanish subject. In the section where it was found there are +several fountains of a peculiar substance. It is a black liquid, of +little density, strongly impregnated with carbonic acid which it +transmits to the water which invariably accompanies it. Deposits of this +substance are found at the foot of the spurs of the Cordilleras, and are +believed to indicate the presence of great deposits of anthracite. + +There are many petroleum wells of inferior quality between Escuque and +Bettijoque, in the town of Columbia. Laborers gather the petroleum in +handkerchiefs. After these become saturated, the oil is pressed out by +wringing. It is burned in the houses of the poor. The people thought, in +1824, that it was a substance unknown elsewhere, and they called it +the "oil of Columbia." At that time they hoped to establish a valuable +industry by working it, and they sent to England, France, and this +country samples which attracted much attention. But in those days no +method of refining the crude oil had been discovered, and therefore +these efforts to introduce petroleum to the world soon failed. + +The plains of Ceniza abound in asphalt and petroleum. There is a large +lake of these substances about twelve kilometers east of St. Timoteo, +and from it some asphalt is taken to Maracaibo. Many deposits of asphalt +are found between these plains and the River Mene. The largest is that +of Cienega de Mene, which is shallow. At the bottom lies a compact +bed of asphalt, which is not used at present, except for painting +the bottoms of vessels to keep off the barnacles. There are wells of +petroleum in the State of Falcon. + +Mr. Plumacher says that all the samples of coal submitted to him in +Venezuela for examination, with the exception of the "lignite" before +mentioned, were, in his opinion, asphalt in various degrees of +condensation. The sample which came from Tule he ranks with the coals +of the best quality. He believes that the innumerable fountains and +deposits of petroleum, bitumen, and asphalt that are apparent on the +surface of the region around Lake Maracaibo are proof of the existence +below of immense deposits of coal. These deposits have not been +uncovered because the territory remains for the most part as wild as it +was at the conquest. + + * * * * * + + + + +ONE THOUSAND HORSE-POWER CORLISS ENGINE. + + +[Illustration: FIG. 1. + +DIA. OF CYLINDER = 40'' +STROKE = 10 ft. +REVS = 41 +SCALE OF DIAGRAMS 40 LBS = 1 INCH + +FIG. 2.] + +We illustrate one of the largest Corliss engines ever constructed. It is +of the single cylinder, horizontal, condensing type, with one cylinder +40 inches diameter, and 10 feet stroke, and makes forty-five revolutions +per minute, corresponding to a piston speed of 900 feet per minute. At +mid stroke the velocity of the piston is 1,402 feet per minute nearly, +and its energy in foot pounds amounts to about 8.6 times its weight. +The cylinder is steam jacketed on the body and ends, and is fitted with +Corliss valves and Inglis & Spencer's automatic Corliss valve expansion +gear. Referring to the general drawing of the engine, it will be seen +that the cylinder is bolted directly to the end of the massive cast iron +frame, and the piston coupled direct to the crank by the steel piston +rod and crosshead and the connecting rod. The connecting rod is 28 +feet long center to center, and 12 inches diameter at the middle. The +crankshaft is made of forged Bolton steel, and is 21 inches diameter at +the part where the fly-wheel is carried. The fly driving wheel is 35 +feet in diameter, and grooved for twenty-seven ropes, which transmit the +power direct to the various line shafts in the mill. The rope grooves +are made on Hick, Hargreaves & Co.'s standard pattern of deep groove, +and the wheel, which is built up, is constructed on their improved plan +with separate arms and boss, and twelve segments in the rim with joints +planed to the true angle by a special machine designed and made by +themselves. The weight of the fly-wheel is about 60 tons. The condensing +apparatus is arranged below, so that there is complete drainage from the +cylinder to the condenser. The air pump, which is 36 inches diameter and +2 feet 6 inches stroke, is a vertical pump worked by wrought iron +plate levers and two side links, shown by dotted lines, from the main +crosshead. The engine is fenced off by neat railing, and a platform with +access from one side is fitted round the top of the cylinder for getting +conveniently to the valve spindles and lubricators. The above engraving, +which is a side elevation of the cylinder, shows the valve gear +complete. There are two central disk plates worked by separate +eccentrics, which give separate motion to the steam and exhaust valves. +The eccentrics are mounted on a small cross shaft, which is driven by a +line shaft and gear wheels. The piston rod passes out at the back end of +the cylinder and is carried by a shoe slide and guide bar, as shown more +fully in the detailed sectional elevation through the cylinder, showing +also the covers and jackets in section. The cylinder, made in four +pieces, is built up on Mr. W. Inglis's patent arrangement, with separate +liner and steam jacket casing and separate end valve chambers. This +arrangement simplifies the castings and secures good and sound ones. The +liner has face joints, which are carefully scraped up to bed truly to +the end valve chambers. The crosshead slides are each 3 feet 3 inches +long and I foot 3 inches wide. The engine was started last year, and +has worked beautifully from the first, without heating of bearings or +trouble of any kind, and it gives most uniform and steady turning. It is +worked now at forty-one revolutions per minute, or only 820 feet piston +speed, but will be worked regularly at the intended 900 feet piston +speed per minute when the spinning machinery is adapted for the increase +which the four extra revolutions per minute of the engine will give; the +load driven is over 1,000 horsepower, the steam pressure being 50 lb. +to 55 lb., which, however, will be increased when the existing boilers, +which are old, come to be replaced by new. Indicator diagrams from the +engines are given on page 309. The engine is very economical in steam +consumption, but no special trials or tests have been made with it. An +exactly similar engine, but of smaller size, with a cylinder 30 inches +diameter and 8 feet stroke, working at forty-five revolutions per +minute, made by Messrs. Hick, Hargreaves & Co. for Sir Titus Salt, +Sons & Co.'s mill at Saltaire, was tested about two years ago by Mr. +Fletcher, chief engineer of the Manchester Steam Users' Association, and +the results which are given below pretty fairly represent the results +obtained from this class of engine. Messrs. Hick, Hargreaves & Co. are +now constructing a single engine of the same type for 1,800 indicated +horse-power for a cotton mill at Bolton; and they have an order for a +pair of horizontal compound Corliss engines intended to indicate 3,000 +horse-power. These engines will be the largest cotton mill engines in +the world.--_The Engineer_. + +[Illustration: 1000 HORSE POWER CORLISS ENGINE.--BY HICK. HARGREAVES & +CO.] + +_Result of Trials with Saltaire Horizontal Engine on February 14th and +15th, 1878. Trials made by Mr. L.E. Fletcher, Chief Engineer Steam +Users' Association, Manchester._ + +Engine single-cylinder, with Corliss valves. Inglis and Spencer's valve +gear. Diameter of cylinder. 30in.; stroke, 8ft.; 45 revolutions per +minute. + +No. of trials +Total 1.H.P. +[MB] Mean boiler pressure. +[MP] Mean pressure on piston at beginning of stroke. +[ML] Mean loss between boiler pressure and cylinder. +[MA] Mean average pressure on piston. +[W] Water Per I.H.P. per hour. +[C] Coal per I.H.P. per hour. + +No. of trials Total MB MP ML MA W C + I.H.P. lb lb lb lb lb lb +Trial No. 1. 301.89 46.6 44.11 2.53 21.23 18.373 2.699 +Trial No. 2. 309.66 47.63 44.45 3.18 21.67 17.599 2.561 +Means. 305.775 47.115 44.28 2.855 21.45 17.986 2.630 + +[Illustration: 1000 HORSE POWER CORLISS ENGINE.--BY HICK, HARGREAVES +& CO.] [Illustration: 1000 HORSE POWER CORLISS ENGINE.--BY HICK, +HARGREAVES & CO.] + + * * * * * + + + + +OPENING OF THE NEW WORKSHOP OF THE STEVENS INSTITUTE OF TECHNOLOGY. + + +In our SUPPLEMENT No. 283 we gave reports of some of the addresses of +the distinguished speakers, and we now present the remarks of Prof. +Raymond and Horatio Allen, Esq.: + + +SPEECH OF PROF. R. W. RAYMOND. + +A few years ago, at one of the meetings of our Society of Civil +Engineers we spent a day or so in discussing the proper mode of +educating young men so as to fit them for that profession. It is a +question that is reopened for us as soon as we arrive at the age when +we begin to consider what career to lay out for our sons. When we were +young, the only question with parents in the better walks of life was, +whether their sons should be lawyers, physicians, or ministers. Anything +less than a professional career was looked upon as a loss of caste, a +lowering in the social scale. These things have changed, now that we +engineers are beginning to hold up our heads, as we have every reason to +do; for the prosperity and well-being of the great nations of the world +are attributable, perhaps, more to our efforts than to those of any +other class. When, in the past, the man of letters, the poet, the +orator, succeeded, by some fit expression, by some winged word, to +engage the attention of the world concerning some subject he had at +heart, the highest praise his fellow man could bestow was to cry out +to him, "Well said, well said!" But now, when, by our achievements, +commerce and industry are increased to gigantic proportions, when the +remotest peoples are brought in ever closer communication with us, when +the progress of the human race has become a mighty torrent, rushing +onward with ever accelerating speed, we glory in the yet higher praise, +"Well done, well done!" Under these circumstances, the question how a +young man is best fitted for our profession has become one of increasing +importance, and three methods have been proposed for its solution. +Formerly the only point in debate was whether the candidate should go +first to the schools and then to the workshop, or first to the shop and +then to the schools. It was difficult to arrive at any decision; for of +the many who had risen to eminence as engineers, some had adopted +one order and some the other. There remained a third course, that of +combining the school and the shop and of pursuing simultaneously the +study of theory and the exercise of practical manipulation. Unforeseen +difficulties arose, however, in the attempt to carry out this, the most +promising method. The maintenance of the shop proved a heavy expense, +which it was found could not be lessened by the manufacture of salable +articles, because the work of students could not compete with that of +expert mechanics. It would require more time than could be allotted, +moreover, to convert students into skilled workmen. Various +modifications of this combination of theory and practice, including more +or less of the Russian system of instruction in shop-work, have been +tried in different schools of engineering, but never under so favorable +conditions as the present. With characteristic caution and good +judgment, President Morton has studied the operation of the scheme +of instruction adopted in the Stevens Institute, and, noting its +deficiencies, has now supplied them with munificent liberality, giving +to it a completeness that leaves seemingly nothing that could be +improved upon, even in a prayer or a dream. Still, no one will be more +ready to admit than he who has done all this, that it is not enough to +fit up a machine shop, be it never so complete, and light it with an +electric lamp. The decision as to its efficiency must come from the +students that are so fortunate as to be admitted to it. If such young +men, earnest, enthusiastic, with every incentive to exertion and every +advantage for improvement, here, where they can feel the throbbing of +the great heart of enterprise, within sight of bridges upon which their +services will be needed, within hearing of the whistles of a score of +railroads, and the bells of countless manufactories which will want +them; if such as these, trained under such instructors and amid such +surroundings, prove to be not fitted for the positions waiting for them +to fill, it will have been definitely demonstrated that the perfect +scheme is yet unknown. + + +SPEECH OF MR. HORATIO ALLEN. + +Impressed with the very great step in advance which has been inaugurated +here this evening, I feel crowding upon me so many thoughts that I +cannot make sure that, in selecting from them, I may not leave unsaid +much that I should say, and say some things that I had better omit. Some +years ago, when asked by a wealthy gentleman to what machine-shop he had +best send his son, who was to become a mechanical engineer, I advised +him not to send him to any, but to fit up a shop for him where he could +go and work at what he pleased without the drudgery of apprenticeship, +to put him in the way of receiving such information as he needed, and +especially to let him go where he could see things break. Great, indeed, +are the advantages of those who have the opportunity of seeing things +break, of witnessing failures and profiting by them. When men have +enumerated the achievements of those most eminent in our profession the +thought has often struck me, "Ah! if we could only see that man's scrap +heap." + +There are many who are able to construct a machine for a given purpose +so that it will work, but to do this so that it will not cost too much +is an entirely different problem. To know what to omit is a rare talent. +I once found a young man who could tell students what to store up in +their minds for immediate use, and what to skim over or omit; but I +could not keep him long, for more lucrative positions are always waiting +for such men. + +The advice I gave my wealthy friend was given before the Stevens +Institute had developed in the direction it has now. The foundation of +this advice, namely, to combine a certain amount of judicious practice +with theory, is now in a fair way to be carried out, and although +things will probably not be permitted to break here, the students will +doubtless have opportunities for looking around them and supplementing +their systematic instruction here by observation abroad. + + * * * * * + + + + +LIGHT STEAM ENGINE FOR BALLOONS. + + +We here illustrate one of a couple of compound engines designed and +constructed by Messrs. Ahrbecker, Son & Hamkens, of Stamford Street, +S.E., for Captain Mojaisky, of the Russian Imperial Navy, who intends +to use them for aeronautical purposes. The larger of these engines has +cylinders 3¾ in. and 7½ in. in diameter and 5 in. stroke, and when +making 300 revolutions per minute it develops 20 actual horse +power, while its weight is but 105 lbs. The smaller engine--the one +illustrated--has cylinders 2½ in. and 5 in. in diameter, and 3½ in. +stroke, and weighs 63 lbs., while when making 450 revolutions it +develops 10 actual horse power. + +The two engines are identical in design, and are constructed of forged +steel with the exception of the bearings, connecting-rods, crossheads, +slide valves and pumps, which are of phosphor-bronze. The cylinders, +with the steam passages, etc., are shaped out of the solid. The +standards, as will be seen, are of very light T steel, the crankshafts +and pins are hollow, as are also the crosshead bolts and piston rods. +The small engine drives a single-acting air pump of the ordinary type by +a crank, not shown in the drawing. The condenser is formed of a series +of hollow gratings. + +[Illustration: LIGHT STEAM ENGINE FOR AERONAUTICAL PURPOSES] + +Steam is supplied to the two engines by one boiler of the Herreshoff +steam generator type, with certain modifications, introduced by the +designers, to insure the utmost certainty in working. It is of steel, +the outside dimensions being 22 in. in diameter, 25 in. high, and weighs +142 lb. The fuel used is petroleum, and the working pressure 190 lb. per +square inch. + +The constructors consider the power developed by these engines very +moderate, on account of the low piston speed specified in this +particular case. In some small and light engines by the same makers +the piston speed is as high as 1000 ft. per minute. The engines now +illustrated form an interesting example of special designing, and +Messrs. Ahrbecker, Son, and Hamkens deserve much credit for the manner +in which the work has been turned out, the construction of such light +engines involving many practical difficulties,--_Engineering._ + + * * * * * + +Mount Baker, Washington Territory, has shown slight symptoms of volcanic +activity for several years. An unmistakable eruption is now in progress. + + * * * * * + + + + +COMPLETE PREVENTION OF INCRUSTATION IN BOILERS. + + +The chemical factory, Eisenbuettel, near Braunschweig, distributes the +following circular: "The principal generators of incrustation in boilers +are gypsum and the so-called bicarbonates of calcium and magnesium. If +these can be taken put of the water, before it enters the boiler, the +formation of incrustation is made impossible; all disturbances and +troubles, derived from these incrustations, are done away with, and +besides this, a considerable saving of fuel is possible, as clear iron +will conduct heat quicker than that which is covered with incrustation." + +J. Kolb, according to _Dingler's Polyt. Journal_, says: "A boiler with +clear sides yielded with 1 kil. coal 7.5 kil. steam, after two months +only 6.4 kil. steam, or a decrease of 17 per cent. At the same time the +boiler had suffered by continual working." + +Suppose a boiler free from inside crust would yield a saving of only +5 per cent. in fuel (and this figure is taken very low compared with +practical experiments) it would be at the same time a saving of 3c. per +cubic meter water. If the cleaning of one cubic meter water therefore +costs less than 3c., this alone would be an advantage. + +Already, for a long time, efforts have been made to find some means for +this purpose, and we have reached good results with lime and chloride of +barium, as well as with magnesia preparations. But these preparations +have many disadvantages. Corrosion of the boiler-iron and muriatic acid +gas have been detected. (Accounts of the Magdeburg Association for +boiler management.) + +Chloride of calcium, which is formed by using chloride of barium, +increases the boiling point considerably, and diminishes the elasticity +of steam; while the sulphate of soda, resulting from the use of +carbonate of soda, is completely ineffectual against the boiler iron. +It increases the boiling point of water less than all other salts, and +diminishes likewise the elasticity of steam (Wullner). + +In using magnesia preparation, the precipitation is only very slowly and +incompletely effected--one part of the magnesia will be covered by the +mire and the formed carbonate of magnesia in such a way, that it can no +more dissolve in water and have any effect (_Dingler's Polyt. Journal_, +1877-78). + +The use of carbonate of soda is also cheaper than all other above +mentioned substances. + +One milligramme equivalent sulphate of lime, in 1 liter, = 68 grammes +sulphate of lime in 1 cubic meter, requiring for decomposition: + +120 gr. (86-88 per cent.) chloride of barium of commerce--at $5.00 = +0.6c. + +Or, 50 gr. magnesia preparation--at $10.00 = 0.5c. + +Or, 55 gr. (96-98 per cent.) carbonate of soda--at $7.50 = 0.41c. + +The proportions of cost by using chloride of barium, magnesia +preparation, carbonate of soda, will be 6 : 5 : 4. + + +ARRANGEMENT FOR PURIFYING BOILER-WATER WITH LIME AND CARBONATE OF SODA. + +We need for carrying out these manipulations, according to the size +of the establishment, one or more reservoirs for precipitating the +impurities of the water, and one pure water reservoir, to take up the +purified water; from the latter reservoir the boilers are fed. The most +practical idea would be to arrange the precipitating reservoir in such +manner that the purified water can flow directly into the feeding +reservoir. + +The water in the precipitating reservoir is heated either by adding +boiling water or letting in steam up to 60° C. at least. The +precipitating reservoirs (square iron vessels or horizontal +cylinders--old boilers) of no more than 4 or 4½ feet, having a faucet 6 +inches above the bottom, through which the purified water is drawn off, +and another one at the bottom of the vessel, to let the precipitate off +and allow of a perfect cleaning. In a factory with six or seven boilers +of the usual size, making together 400 square meters heating surface, +two precipitating reservoirs, of ten cubic meters each, and one pure +water reservoir of ten or fifteen cubic meter capacity, are used. + +In twenty-four hours about 240 cubic meters of water are evaporated; we +have, therefore, to purify twenty-four precipitating reservoirs at ten +cubic meters each day, or ten cubic meters each hour. + +It is profitable to surround the reservoirs with inferior conductors of +heat, to avoid losses. + +The contents of the precipitating reservoirs have to be stirred up very +well, and for this purpose we can either arrange a mechanical stirrer +or do it by hand, or the best would be a "Korting steam stirring and +blowing apparatus." In using the latter we only have to open the valve, +whereby in a very short time the air driven through the water stirs this +up and mixes it thoroughly with the precipitating ingredients. In a +factory where boilers of only 15 to 100 square meters heating surface +are, one precipitating reservoir of two to ten cubic meters and one pure +water reservoir of three to ten cubic meters capacity are required. For +locomobiles, two wooden tubs or barrels are sufficient. + + +THE PURIFICATION OF THE WATER. + +After the required quantity of lime and carbonate of soda which is +necessary for a total precipitation has been figured out from the +analysis of the water, respectively verified by practical experiments +in the laboratory, the heated water in the reservoir is mixed with the +lime, in form of thin milk of lime, and stirred up; we have to add so +much lime, that slightly reddened litmus paper gives, after ¼ minute's +contact with this mixture, an alkaline reaction, i.e., turns blue; now +the solution of carbonate of soda is added and again stirred well. + +After twenty or thirty minutes (the hotter the water, the quicker the +precipitation) the precipitate has settled in large flocks at the +bottom, and the clear water is drawn off into the pure water reservoir. +The precipitating and settling of the impurities can also take place in +cold water; it will require, however, a pretty long time. + +In order to avoid the weighing and slaking of the lime, which is +necessary for each precipitation, we use an open barrel, in which a +known quantity of slaked lime is mixed with three and a half or four +times its weight of water, and then diluted to a thin paste, so that one +kilogramme slaked lime is diluted to twenty-five liters milk of lime. + +Example.--If we use for ten cubic meters water, one kilogramme lime, +or in one day (in twenty-four hours), 240 cubic meters 24 kg. lime, a +vessel four or five feet high and about 700 liters capacity, in which +daily 24 kg. lime with about 100 liters water are slaked and then +diluted to the mark 600, constantly stirring, 25 liters of this mixture +contain exactly 1 kg. slaked lime. + +Before using, this milk of lime has to be stirred up and allowed to +settle for a few seconds; and then we draw off the required quantity of +milk of lime (in our case 25 liters) through a faucet about 8 inches +above the bottom, or we can dip it off with a pail. For the first +precipitate we always need the exact amount of milk of lime, which we +have figured out, or rather some more, but for the next precipitates we +do not want the whole quantity, but always less, as that part of the +lime, which does not settle with the precipitate, will be good for use +in further precipitations. It is therefore important to control the +addition of milk of lime by the use of litmus paper. If we do not add +enough lime, it prevents the formation of the flocky precipitate, and, +besides, more carbonate of soda is used. By adding too much lime, we +also use more carbonate of soda in order to precipitate the excess of +lime. We can therefore add so much lime, that there is only a very small +excess of hydrous lime in the water, and that after well stirring, a red +litmus paper being placed in the water for twenty seconds, appears only +slightly blue. After a short time of practice, an attentive person can +always get the exact amount of lime which ought to be added. On adding +the milk of lime, we have to dissolve the required amount of pure +carbonate of soda in an iron kettle, in about six or eight parts hot +water with the assistance of steam; add this to the other liquid in the +precipitating reservoirs and stir up well. The water will get clear +after twenty-five or thirty minutes, and is then drawn off into the pure +water reservoir. + + +EXAMINATION OF WATER WHICH HAS BEEN PURIFIED BY MEANS OF MILK OF LIME +AND CARBONATE OF SODA. + +In order to be convinced that the purification of the water has been +properly conducted, we try the water in the following manner. Take a +sample of the purified water into a small tumbler, and add a few +drops of a solution of oxalate of ammonia; this addition must neither +immediately nor after some minutes cause a milky appearance of the +water, but remain bright and clear. A white precipitate would indicate +that not enough carbonate of soda had been added. A new sample is taken +of the purified water and a solution of chloride of calcium added; a +milky appearance, especially after heating, would show that too much +carbonate of soda had been added. + + +RESULTS OF THIS WATER PURIFICATION. + +1. The boilers do not need to be cleaned during a whole season, as they +remain entirely free from incrustation; it is only required to avoid a +collection of soluble salts in the boiler, and therefore it is partly +drawn off twice a week. + +2. The iron is not touched by this purified water. The water does not +froth and does not stop up valves. The fillings in the joints of pipes, +etc., do not suffer so much, and therefore keep longer. + +3. The steam is entirely free from sour gases. + +4. The production of steam is easier and better. + +5. A considerable saving of fuel can soon be perceived. + +6. The cost of cleaning boilers from incrustation, and loss of time +caused by cleaning, is entirely done with. Old incrustations, which +could not be cleaned out before, get decomposed and break off in soft +pieces. + +7. The cost of this purification is covered sufficiently by the above +advantages, and besides this, the method is cheaper and surer than any +other. + +The chemical factory, Eisenbuettel, furnishes pure carbonate of soda in +single packages, which exactly correspond with the quantity, stated by +the analysis, of ten cubic meters of a certain water. The determination +of the quantities of lime and carbonate of soda necessary for a certain +kind of water, after sending in a sample, will be done without extra +charge.--_Neue Zeitung fur Ruebenzucker Industrie_. + + * * * * * + + + + +EDDYSTONE LIGHTHOUSE. + + +The exterior work on the new Eddystone Lighthouse is about two thirds +done. In the latter part of April fifty-three courses of granite +masonry, rising to the height of seventy feet above high water, had been +laid, and thirty-six courses remained to be set. The old lighthouse had +been already overtopped. As the work advances toward completion the +question arises: What shall be done with John Smeaton's famous tower, +which has done such admirable service for 120 years? One proposition is +to take it down to the level of the top of the solid portion, and +leave the rest as a perpetual memorial of the great work which Smeaton +accomplished in the face of obstacles vastly greater than those which +confront the modern architect. The London _News_ says: "Were Smeaton's +beautiful tower to be literally consigned to the waves, we should regard +the act as a national calamity, not to say scandal; and, if public funds +are not available for its conservation, we trust that private zeal and +munificence may be relied on to save from destruction so interesting +a relic. It certainly could not cost much to convey the building in +sections to the mainland, and there, on some suitable spot, to re-erect +it as a national tribute to the genius of its great architect." When +the present lighthouse was built one of the chief difficulties was in +getting the building materials to the spot. They were conveyed from +Millbay in small sailing vessels, which often beat about for days before +they could effect a landing at the Eddystone rocks, so that each arrival +called out the special gratitude of Smeaton. + + * * * * * + + + + +ROLLING-MILL FOR MAKING CORRUGATED IRON. + + +MESSRS. SCHULZ, KNAUDT & Co., of Essen, who are making an application +of corrugated iron in the construction of the interior flues of steam +boilers, have devised a new mill for the manufacture of this form of +iron plates, and which is represented in the accompanying cut, taken +from the _Deutsche Industrie Zeitung_. The supports of the two accessory +cylinders, F F, rest on two slides, G G, which move along the oblique +guides, H H. As a consequence of this arrangement, when the cylinders, F +F, are caused to approach the cylinder, D, both are raised at the same +instant. + +When the cylinders, F, occupy the position represented in the engraving +by unbroken lines, the flat plate, O, is simply submitted to pressure +between the cylinders, D and P, the cylinders, F F, then merely acting +as guides. But when, while the plate is being thus flattened between the +principal cylinders, the accessory cylinders are caused to rise, the +plate is curved as shown by the dotted lines, O' O'. To obtain a +uniformity in the position of the two cylinders, F F, the following +mechanism is employed: Each cylinder has an axle, to which is affixed a +crank, Q, connected by means of a rod, R, with the slide, G. These axles +are also provided with toothed sectors, L L, which gear with two screws, +L L, whose threads run in opposite directions. These screws are mounted +on a shaft, N, which may be revolved by any suitable arrangement. + +[Illustration: ROLLING MILL FOR MAKING CORRUGATED IRON] + + * * * * * + + + + +RAILWAY TURN-TABLE IN THE TIME OF LOUIS XIV. + + +The small engraving which we reproduce herewith from _La Nature_ is +deposited at the Archives at Paris. It is catalogued in the documents +relating to Old Marly, 1714, under number 11,339, Vol. 1. The design +represents a diversion called the _Jeu de la Roulette_ which was +indulged in by the royal family at the sumptuous and magnificent chateau +of Mary-le-Roi. + +[Illustration: PLEASURE CAR; RAILWAY AND TURN-TABLE OF THE TIME OF LOUIS +XIV.] + +According to Alex. Guillaumot the apparatus consisted of a sort of +railway on which the car was moved by manual labor. In the car, which +was decorated with the royal colors, are seen seated the ladies and +children of the king's household, while the king himself stands in the +rear and seems to be directing operations. The remarkable peculiarity to +which we would direct the attention of the reader is that this document +shows that the car ran on rails very nearly like those used on the +railways of the present time, and that a turn-table served for changing +the direction to a right angle in order to place the car under the +shelter of a small building. The picture which we reproduce, and the +authenticity of which is certain, proves then that in the time of +Louis XIV. our present railway turn-tables had been thought of and +constructed--which is a historic fact worthy of being noted. It is well +known that the use of railways in mines is of very ancient date, but we +do not believe that there are on record any documents as precise as that +of the _Jeu de la Roulette_ as to the existence of turn-tables in former +ages. + + * * * * * + + + + +NEW SIGNAL WIRE COMPENSATOR. + + +_To the Editor of the Scientific American_: + +I send you a plate of my new railway signal wire compensator. Here +in India signal wires give more trouble, perhaps, than in America or +elsewhere, by expansion and contraction. What makes the difficulty more +here is the ignorance and indolence of the point and signalmen, who +are all natives. There have been numerous collisions, owing to signals +falling off by contraction. Many devices and systems have been tried, +but none have given the desired result. You will observe the signal wire +marked D is entirely separated and independent of the wire, E, leading +to lever. On the Great Indian and Peninsula Railway I work one of these +compensators, 1,160 yards from signal, which stands on a summit the +grade of which is 1 in 150; and on the Nizam State Railway I have one +working on a signal 800 yards. This signal had previously given so much +trouble that it was decided to do away with it altogether. It stands on +top of a high cutting and on a 1,600 foot curve. + +[Illustration: Railway Signal Wire Comensator] + +I have noted on the compensator fixed at 1,160 yards, 13¼ inches +contraction and expansion. The compensator is very simple and not at all +likely to get out of order. On new wire, when I fix my compensator, I +usually have an adjusting screw on the lead to lever. This I remove +when the wire has been stretched to its full tension. I have everything +removed from lever, so there can be no meddling or altering. When +once the wire is stretched so that no slack remains between lever and +trigger, no further adjustment is necessary. + +A. LYLE, + +Chief Maintenance Inspector, Permanent Way, + +H.H. Nizam State Railway, E. India. + +Secunderabad, India, 1881. + + + + +TANGYE'S HYDRAULIC HOIST. + + +[Illustration: TANGYE'S HYDRAULIC HOIST.] + +The great merits of hydraulic hoists generally as regards safety and +readiness of control are too well known to need pointing out here. +We may, therefore, at once proceed to introduce to our readers the +apparatus of this class illustrated in the above engravings. This is +a hoist (Cherry's patent) manufactured by Messrs. Tangye Brothers, of +London and Birmingham, and which experience has proved to be a most +useful adjunct in warehouses, railway stations, hotels, and the like. +Fig. 1 of our engraving shows a perspective view of the hoist, Fig. 2 +being a longitudinal section. It will be seen that this apparatus is of +very simple construction, the motion of the piston being transmitted +directly to the winding-drum shaft by means of a flexible steel rack. +Referring to Fig. 2, F is a piston working in the cylinder, G; E is +the flexible steel rack connected to the piston, F, and gearing with a +toothed wheel, B, which is inclosed in a watertight casing having cover, +D, for convenient access. The wheel, B, is keyed on a steel shaft, C, +which passes through stuffing-boxes in the casing, and has the winding +barrel, A, keyed on it outside the casing. H is a rectangular tube, +which guides the free end of the flexible steel rack, E. The hoist is +fitted with a stopping and starting valve, by means of which water +under pressure from any convenient source of supply may be admitted or +exhausted from the cylinder. The action in lifting is as follows: The +water pressure forces the piston toward the end of the cylinder. The +piston, by means of the flexible steel rack, causes the toothed wheel +to revolve. The winding barrel, being keyed on the same shaft as the +toothed wheel, also revolves, and winds up the weight by means of the +lifting chain. Two special advantages are obtained by this simple method +of construction. In the first place, twice the length of stroke can be +obtained in the same space as compared with the older types of hydraulic +hoist; and, from the directness of the action, the friction is reduced +to a minimum. This simple method of construction renders the hoist very +compact and easily fixed; and, from the directness with which the power +is conveyed from the piston to the winding drum, and the frictionless +nature of the mechanism, a smaller piston suffices than in the ordinary +hydraulic hoists, and a smaller quantity of water is required to work +them.--_Iron_. + + * * * * * + + + + +POWER LOOM FOR DELICATE FABRICS. + + +The force with which the shuttle is thrown in an ordinary power +loom moving with a certain speed is always considerable, and, as a +consequence of the strain exerted on the thread, it is frequently +necessary to use a woof stronger than is desirable, in order that it may +have sufficient resistance. On another hand, when the woof must be very +fine and delicate the fabric is often advantageously woven on a hand +loom. In order to facilitate the manufacture of like tissues on the +power loom the celebrated Swiss manufacturer, Hanneger, has invented an +apparatus in which the shuttle is not thrown, but passed from one side +to the other by means of hooks, by a process analogous to weaving silk +by hand. A loom built on this principle was shown at work weaving silk +at the Paris Exhibition of 1878. This apparatus, represented in +the annexed figure, contains some arrangements which are new and +interesting. On each side of the woof in the heddle there is a carrier, +B. These carriers are provided with hooks, A A', having appendages, +_a a'_, which are fitted in the shuttle, O. The latter is of peculiar +construction. The upper ends of the hooks have fingers, _d d'_, which +holds the shuttle in position as long as the action of the springs, _e +e'_, continues. The distance that the shuttle has to travel includes the +breadth of the heddle, the length of the shuttle, and about four inches +in addition. The motion of the two carriers, which approach each other +and recede simultaneously, is effected by the levers, C, D, E, and C', +D', E'. The levers, E, E', are actuated by a piece, F, which receives +its motion from the main shaft, H, through the intervention of a +crank and a connecting rod, G, and makes a little more than a quarter +revolution. The levers, E, E', are articulated in such a way that +the motion transmitted by them is slackened toward the outer end and +quickened toward the middle of the loom. While the carriers, B B', are +receiving their alternate backward and forward motion, the shaft, I +(which revolves only half as fast as the main shaft), causes a lever, F +F', to swing, through the aid of a crank, J, and rod, K. Upon the two +carriers, B B', are firmly attached two hooks, M M', which move with +them. When the hook, M, approaches the extremity of the lever, F, the +latter raises it, pushes against the spring, E, and sets free the +shuttle, which, at the same moment, meets the opposite hook, _a'_, and, +being caught by it, is carried over to the other side. The same thing +happens when the carrier, B', is on its return travel, and the hook, M', +mounts the lever, F', which is then raised. + +[Illustration: POWER LOOM FOR DELICATE FABRICS.] + +As will be seen from this description, the woof does not undergo the +least strain, and may be drawn very gently from the shuttle. Neither +does this latter exert any friction on the chain, since it does not move +on it as in ordinary looms. In this apparatus, therefore, there may be +employed for the chain very delicate threads, which, in other looms, +would be injured by the shuttle passing over them. Looms constructed on +this plan have for some time been in very successful use in Switzerland. + + * * * * * + + + + +HOW VENEERING IS MADE. + + +The process of manufacture is very interesting. The logs are delivered +in the mill yard in any suitable lengths as for ordinary lumber. A steam +drag saw cuts them into such lengths as may be required by the order +in hand; those being cut at the time of our visit were four feet long. +After cutting, the logs are placed in a large steam box, 15 feet wide, +22 feet long, and six feet high, built separate from the main building. +This box is divided into two compartments. When one is filled entirely +full, the doors are closed, and the steam, supplied by the engine in the +main building, is turned on. The logs remain in this box from three to +four hours, when they are ready for use. This steaming not only removes +the bark, but moistens and softens the entire log. From the steam box +the log goes to the veneer lathe. It is here raised, grasped at each end +by the lathe centers, and firmly held in position, beginning to slowly +revolve. Every turn brings it in contact with the knife, which is gauged +to a required thickness. As the log revolves the inequalities of its +surface of course first come in contact with the keen-edged knife, and +disappear in the shape of waste veneer, which is passed to the engine +room to be used as fuel. Soon, however, the unevenness of the log +disappears, and the now perfect veneer comes from beneath the knife in +a continuous sheet, and is received and passed on to the cutting table. +This continues until the log is reduced to about a seven inch core, +which is useless for the purpose. The veneer as it comes rolling off the +log presents all the diversity of colors and the beautiful grain and +rich marking that have perhaps for centuries been growing to perfection +in the silent depths of our great forests. + +From the lathe, the veneer is passed to the cutting table, where it is +cut to lengths and widths as desired. It is then conveyed to the second +story, where it is placed in large dry rooms, air tight, except as the +air reaches them through the proper channels. The veneer is here placed +in crates, each piece separate and standing on edge. The hot air is then +turned on. This comes from the sheet iron furnace attached to the boiler +in the engine room below, and is conveyed through large pipes regulated +by dampers for putting on or taking off the heat. There is also a blower +attached which keeps the hot air in the dry rooms in constant motion, +the air as it cools passing off through an escape pipe in the roof, +while the freshly heated air takes its place from below. These rooms +are also provided with a net-work of hot air pipes near the floor. The +temperature is kept at about 165°, and so rapid is the drying process +that in the short space of four hours the green log from the steam box +is shaved, cut, dried, packed, and ready for shipment. + +After leaving the dry rooms it is assorted, counted, and put up in +packages of one hundred each, and tied with cords like lath, when it is +ready for shipment. Bird's-eye maple veneer is much more valuable and +requires more care than almost any other, and this is packed in cases +instead of tied in bundles. The drying process is usually a slow one, +and conducted in open sheds simply exposed to the air. Mr. Densmore's +invention will revolutionize this process, and already gives his mill a +most decided advantage. + +The mill will cut about 30,000 feet of veneer in a day, and this cut can +be increased to 40,000 if necessary. Mr. Densmore has already received +several large orders, and the rapidly increasing demand for this +material is likely to give the mill all the work it can do. The timber +used is principally curled and bird's-eye maple, beech, birch, cherry, +ash, and oak. These all grow in abundance in this vicinity, and the +beautifully marked and grained timber of our forests will find fitting +places in the ornamental uses these veneers will be put to. + + * * * * * + + + + +THE CONSTITUENT PARTS OF LEATHER. + + +The constituent parts of leather seem to be but little understood. The +opinions of those engaged in the manufacture of leather differ widely on +this question. + +Some think that tannin assimilates itself with the hide and becomes +fixed there by reason of a special affinity. Others regard the hide as +a chemical combination of gelatine and tannin. We know that the hide +contains some matters which are not ineradicable, but only need a slight +washing to detach them. + +We deem it advisable, in order to examine the hide properly so-called, +to dispense with those eradicable substances which may be regarded, to +some extent, as not germain to it, and confine our attention to the raw +stock, freed from these imperfections. + +It is well known that a large number of vegetable substances are +employed as tanning agents. Our researches have been directed to leather +tanned by means of the most important of these agents. + +Many questions present themselves in the course of such an examination. +Among others, that most important one, from a practical point of view, +of the weight the tanning agent gives to the hide, that is to say, the +result in leather of weight given to the raw material. The degree of +tannage is also to be considered; the length of time during which the +tanning agent is to be left with the hide; in short, the influence upon +the leather of the substances used in its production. That is why we +have made the completest possible analysis of different leathers. + +Besides ordinary oak bark there are used at present very different +substances, such as laurel, chestnut, hemlock, quebracho and pine bark, +sumac, etc. + +Water is an element that exists in all hides, and it is necessary to +take it into consideration in the analysis. It is present in perceptible +quantity even in dry hides. This water cannot be entirely eradicated +without injuring the leather, which will lose in suppleness and +appearance. Water should then be considered as one of the elements of +leather, but it must be understood that if it exceeds certain limits, +say 12 to 14 per cent., it becomes useless and even injurious. Moreover, +if there is any excess over the normal quantity, it becomes deceptive +and dishonest, as in such a case one sells for hides that which is +nothing but water. Supposing that a hide, instead of only 14 per cent., +contained 18 per cent. of water, it is evident that in buying 100 pounds +of such a hide one would pay for four pounds of water at the rate for +which he purchased the hide. + +There are, also, some matters soluble in air, which are formed to a +large extent from fat arising as much from the hide as from tanning +substances. The air dissolves at the same time a certain amount of +organic acid and resinous products which the hide has absorbed. After +treating with air, alcohol is used, which dissolves principally the +coloring matters, tannin which has not become assimilated, bodies +analogous to resin, and some extractive substances. + +That which remains after these methods have been pursued ought to be +regarded as the hide proper, that is to say, as the animal tissue +saturated with tannic acid. In this remainder one is able to estimate +with close precision that which belongs to the hide. The hide being an +elementary tissue of unchangeable form, it is easy, in determining the +elementary portion, to find the amount of real hide remaining in the +product. With these elements one can arrive at a solution of some of the +questions we are discussing. + +We give below, according to this method, a table showing the composition +of the different leathers exhibited at the Paris Exposition of 1878. +They are the results of careful research, and we have based our work +upon them: + + Matter Soluble Fixed + in Air Tannin + | | + | Matter Solu- | + | ble in Alcohol | + | | | + Moisture | | Gelatine | + --+-- --+-- --+-- --+-- --+-- +Steer hide, hemlock tanned (heavy leather) 10.95 4.15 19.77 39.1 26.03 +Sheepskins, sumac " (Hungarian) 10.8 10.3 12.1 40.3 26.5 +Finished calf, pine bark tanned (Hungarian) 11.2 1.7 7.4 41.6 38.1 +Steer hide, quebracho tanned (heavy leather) 11.7 1.6 11.2 43.1 32.4 + " " chestnut " " " 13.5 0.29 1.99 45.46 38.76 +Finished calfskins, + oak tanned (Chateau Renault) 12.4 0.33 3.59 46.74 36.94 +Steer hide, laurel tanned (heavy leather) 12.4 1.05 7.95 47.47 31.13 + " " oak tanned after three years in + the vats (heavy leather) 11.45 0.37 3.31 49.85 35.02 + +The following table shows the amount of leather produced by different +tannages of 100 pounds of hides: + + Pounds. +Hemlock 255.7 +Sumac 248.1 +Pine 240.3 +Quebracho 232 +Chestnut 219.9 +Oak 213.9 +Laurel 210.6 +Oak, lasting three years 206 + +It is important to mention here the large proportion of resinous matter +hemlock-tanned leather contains. This resin is a very beautiful red +substance, which communicates its peculiar color to the leather. + +We should mention here that in these calculations we assume that the +hide is in a perfectly dry state, water being a changeable element which +does not allow one to arrive at a precise result. + +These figures show the enormous differences resulting from diverse +methods of tanning. Hemlock, which threatens to flood the markets of +Europe, distinguishes itself above all. The high results attributable to +the large proportion of resin that the hide assimilates, explain in part +the lowness of its price, which renders it so formidable a competitor. +One is also surprised at the large return from sumac-tanned hides when +it is remembered in how short a time the tanning was accomplished, +which, in the present case, only occupied half an hour. + +The figures show us that the greatest return is obtained by means of +those tanning substances which are richest in resin. In short, hemlock, +sumac, and pine, which give the greatest return, are those containing +the largest amount of resin. Thus, hemlock bark gives 10.58 per cent. +of it, and sumac leaves 22.7 per cent., besides the tannin which they +contain. We know also that pine bark is very rich in resin. There is, +then, advantage to the tanner, so far as the question of result is +concerned, in using these materials. There is, however, another side to +the question, as the leather thus surcharged with resin is of inferior +quality, generally has a lower commercial value, and is often of a color +but little esteemed. + +The percentage of tannin absorbed by the different methods of tannages +appears in the following table: + +Hemlock 64.2 +Sumac 61.4 +Pine 90.8 +Quebracho 75.3 +Chestnut 85.2 +Oak 76.9 +Laurel 64.8 +Oak, three years in the vat 70.2 + +The subjoined is a statement of the gelatine and tannin in leather of +different tannages, and also shows the amount of azote or elementary +matter contained in each: + + Gelatine. Tannin. Azote. +Hemlock 60.4 39.6 10.88 +Sumac 60.4 39.6 11 +Pine bark 52.5 47.5 9.56 +Quebracho 57.1 42.9 10.4 +Chestnut 53.97 46.03 9.79 +Oak 55.87 44.13 10.24 +Laurel 60.4 39.6 10.94 +Oak, 3 years in vat 58.75 41.25 10.65 + +It is not pretended that these figures are absolutely correct, as they +often vary in certain limits even for similar products. They form, +however, a fair basis of calculation. + +As to whether leather is a veritable combination, it seems to us that +this question should be answered affirmatively. In fact, the resistance +of leather properly so-called to neutral dissolvents, argues in favor of +this opinion. + +Furthermore, the perceptible proportion of tannin remaining absorbed by +a like amount of hide is another powerful argument. It remains for us to +say here that the differences observable in the quantity of fixed tannin +ought to arise chiefly from the different natures of these tannins, +which have properties differing as do those of one plant from another, +and which really have but one property in common, that of assimilating +themselves with animal tissues and rendering them imputrescible. + +In conclusion, these researches determine the functions of resinous +matters which frequently accompany tannin; they show a very simple +method for estimating the results of one's work, as well as the degree +of tannage.--_Muntz & Schoen, in La Halle aux Cuirs_.--_Shoe & Leather +Reporter_. + + * * * * * + + + + +NEW HIGH SCHOOL FOR GIRLS, OXFORD. + + +The new High School for Girls at Oxford, built by Mr. T.G. Jackson, for +the Girls' Public Day School Company, Limited, was opened September 23, +1880, when the school was transferred from the temporary premises it had +occupied in St. Giles's. The new building stands in St. Giles's road, +East, to the north of Oxford, on land leased from University College, +and contains accommodation for about 270 pupils in 11 class-rooms, some +of which communicate by sliding doors, besides a residence for the +mistress, an office and waiting-room, a room for the teachers, cloak +rooms, kitchens, and other necessary offices, and a large hall, 50 ft. +by 30 ft., for the general assembling of the school together and for use +on speech-days and other public occasions. The principal front faces St. +Giles's road, and is shown in the accompanying illustration. The great +hall occupies the whole of the upper story of the front building, with +the office and cloak-rooms below it, and the principal entrance in the +center. The class-rooms are all placed in the rear of the building, to +secure quiet, and open on each floor into a corridor surrounding the +main staircase which occupies the center of the building. The walls +are built of Headington stone in rubble work, with dressings of brick, +between which the walling is plastered, and the front is enriched with +cornices and pilasters, and a hood over the entrance door, all of terra +cotta. The hinder part of the building is kept studiously simple and +plain on account of expense. Behind the school is a large playground, +which is provided with an asphalt tennis-court, and is picturesquely +shaded with apple-trees, the survivors of an old orchard. The builders +were Messrs. Symm & Co., of Oxford; and the terra cotta was made by +Messrs. Doulton, of Lambeth. Mr. E. Long was clerk of works.--_Building +News_. + +[Illustration: SUGGESTIONS IN ARCHITECTURE--NEW HIGH SCHOOL, OXFORD] + + * * * * * + + + + +PROGRESS IN AMERICAN POTTERY. + + +No advance in any industry has been more sure than in that of pottery +and chinaware, under the American tariff, or more rapid in the past +four or five years. It took Europe three centuries and the jealous +precautions of royal pottery proprietors to build up the great +protectorates that made their distinctive trade-marks of such value. +The earlier lusters of the Italian faience were guild privacies +or individual secrets, as was almost all the craft of the earlier +art-worker. Royal patronage in England was equivalent to a protective +tariff for Josiah Wedgwood; and everywhere the importance of guarding +the china nurseries has been understood. We have in this country +broadcast and in abundance every type of material needed for the +finest china ware, and for the finer glasses and enamels. The royal +manufactories in Europe were hard put to it sometimes for want of +discovering kaolin beds in their dominions, but the resources of the +United States in these particulars needed something more than to be +brought to light. The manipulation and washing of the clays to render +them immediately useful to the potteries depends entirely upon the +reliance of these establishments upon home materials. The Missouri +potteries have their supplies near home, but these supplies must be put +upon the market for other cities in condition to compete with the clays +of Europe. There are fine kaolin beds in Chester and Delaware counties +in this State; there are clay beds in New Jersey, and the recent needs +of Ohio potteries have uncovered fine clay in that State. This shows +that not only for the manufacture itself, but for the development of +material here, everything depends upon the stimulus that protection +gives. + +Ohio china and Cincinnati pottery are known all over the country. The +Chelsea Works, near Boston, however, are as distinguished for their +clays and faience, and for lustrous tiles especially (to be used in +household decoration) can rival the rich show that the Doulton ware made +at the Centennial. Other New England potteries are eminent for terra +cotta and granite wares. On Long Island and in New York city there are +porcelain and terra cotta factories of established fame, and the first +porcelain work to succeed in home markets was made at the still busy +factories of Greenpoint. New Jersey potteries take the broad ground of +the useful, first of all, in their manufacture of excellent granite +and cream-colored ware for domestic use, but every year turn out more +beautiful forms and more artistic work. The Etruria Company especially +have succeeded in giving the warm flesh tints to the "Parian" for busts +and statuettes, now to be seen in many shop windows. These goods ought +always to be labeled and known as American--it adds to their value with +any true connoisseur. Some of these establishments, more than others, +have the enterprise to experiment in native clays, for which the whole +trade owes their acknowledgments. + +The demand all through the country by skillful decorators for the +pottery forms to work upon, points to still greater extensions in this +business of making our own china, and to the employment and good pay of +more thousands than are now employed in it. A collection of American +china, terra cotta, etc., begun at this time and added to from year to +year, will soon be a most interesting cabinet. Both in the eastern +and western manufactories ingenious workers are rediscovering and +experimenting in pastes and glazes and colors, simply because there is a +large demand for all such, and they can be supplied at prices within the +reach of most buyers. It needs only to point out this flourishing state +of things, through the "let-alone" principle, which protection insures +to this industry, to exhibit the threatened damage of the attempt, under +cover of earthenware duties, to get a little free trade through at this +session.--_Philadelphia Public Ledger_. + + * * * * * + + + + +PHOTOGRAPHIC NOTES. + + +_Mr. Warnerke's New Discovery_.--Very happily for our art, we are at the +present moment entering upon a stage of improvement which shows that +photography is advancing with vast strides toward a position that has +the possibility of a marvelous future. In England, especially, great +advances are being made. The recent experiments of our accomplished +colleague, Mr. Warnerke, on gelatine rendered insoluble by light, after +it has been sensitized by silver bromide and developed by pyrogallic +acid, have revealed to us a number of new facts whose valuable results +it is impossible at present to foretell. It seems, however, certain that +we shall thus be able to accomplish very nearly the same effects as +those obtained by bichromatized gelatine, but with the additional +advantage of a much greater rapidity in all the operations. In my own +experiments with the new process of phototypie, I hit upon the plan of +plunging the carbon image, from which all soluble gelatine had been +removed, into a bath of pyrogallic acid, in order to still further +render impermeable the substance forming the printing surface. I also +conceived the idea of afterward saturating this carbon image with a +solution of nitrate of silver, and of subsequently treating it with +pyrogallic acid, in order to still further render impermeable the +substance forming the printing surface. But the process described by Mr. +Warnerke is quite different; by means of it we shall be able to fix +the image taken in the camera, in the same way as we develop carbon +pictures, and afterward to employ them in any manner that may be +desirable. Thus the positive process of carbon printing would be +modified in such a manner that the mixtures containing the permanent +pigment should be sensitized with silver bromide in place of potassium +bichromate. In this way impressions could be very rapidly taken of +positive proofs, and enlargements made, which might be developed in hot +water, just as in the ordinary carbon process, and at least we should +have permanent images. Mr. Warnerke's highly interesting experiments +will no doubt open the way to many valuable applications, and will +realize a marked progress in the art of photography. + +_Method for Converting Negatives Directly into Positives_.--Captain +Bing, who is employed in the topographic studios of the Ministry of +War, has devised a process for the direct conversion of negatives into +positives. The idea is not a new one; but several experimenters, and +notably the late Thomas Sutton, have pointed out the means of effecting +this conversion; it has never, however, so far as I know, been +introduced into actual practice, as is now the case. The process which +I am about to describe is now worked in the studios of the Topographic +Service. The negative image is developed in the ordinary way, but the +development is carried much further than if it were to be used as an +ordinary negative. After developing and thoroughly washing, the negative +is placed on a black cloth with the collodion side downward, and exposed +to diffuse light for a time, which varies from a few seconds to two or +three minutes, according to the intensity of the plate. Afterward the +conversion is effected by moistening the plate afresh, and then plunging +it into a bath which is thus composed: + +Water 700 cub. cents. +Potassium bichromate 30 grams. +Pure nitric acid 300 cub. cents. + +In a few minutes this solution will dissolve all the reduced silver +forming the negative; the negative image is therefore entirely +destroyed; but it has served to impress on the sensitive film beneath +it a positive image, which is still in a latent condition. It must, +therefore, be developed, and to do this, the film is treated with a +solution of-- + +Water 1,000 grams +Pyrogallic acid 25 " +Citric acid 20 " +Alcohol of 36° 50 cub. cents. + +The process is carried on exactly as if developing an ordinary negative; +but the action of the developer is stopped at the precise moment when +the positive has acquired intensity sufficient for the purpose for which +it is to be used. Fixing, varnishing, etc., are then carried on the +usual way. The great advantage of this process consists in the fact of +its rendering positives of much greater delicacy than those that are +taken by contact; and, on the other hand, by means of it we are able to +avoid two distinct operations, when for certain kinds of work we require +positive plates where a negative would be of no service. M. V. Rau, +the assistant who has carried out this process under the direction of +Captain Bing, has described it in a work which has just been published +by M. Gauthier-Villars. + +_Experiments of Captain Bing on the Sensitiveness of Coal Oil_.--The +same Captain of Engineers has undertaken a series of very interesting +experiments on the sensitiveness to light of one or two substances to +which bitumen probably owes its sensitiveness, but which, contrary to +what takes place with bitumen, are capable of rendering very beautiful +half tones, both on polished zinc and on albumenized paper. These +sensitive substances are extracted by dissolving marine glue or coal-tar +in benzine. By exposure to light, both marine-glue and coal-tar turn of +a sepia color, and, in a printing-frame, they render a visible image, +which is not the case with bitumen; their solvents are in the order of +their energy; chloroform, ether, benzine, turpentine, petroleum spirit, +and alcohol. Of these solvents, benzine is the best adapted for reducing +the substances to a fluid state, so as to enable them to flow over the +zinc. The images obtained, which are permanent, and which are very much +like those of the Daguerreotype, are fixed by means of the turpentine +and petroleum spirit. They are washed with water, and then carefully +dried. It is possible to obtain prints with half-tones in fatty ink by +means of plates of zinc coated with marine-glue. Some attempts in this +direction were shown to me, which promised very well in this respect. We +are, therefore, in the right road, not only for economically producing +permanent prints on paper, but also for making zinc plates in which the +phototype film of bichromatized gelatine is replaced by a solution of +marine-glue and benzine. The substance known in commerce under the name +of pitch or coal-tar will produce the same results. + +_Bitumen Plates_.--A new method of making bitumen plates by contact has +also been introduced into the topographical studios. The plan, or the +original drawing, is placed against a glass plate, coated with a mixture +of bitumen and of marine-glue dissolved in benzine. The marine-glue +gives the bitumen greater pliancy, and prevents it from scaling off when +rubbed, particularly when the plate is retouched with a dry point. +These bitumen plates are so thoroughly opaque to the penetration of the +actinic rays, that the printing-frame may be left for any time in full +sunlight without any fear of fog being produced on the zinc plate from +which the prints are to be taken. + +_Method for Topographic Engraving by Commandant de la Noë_.--Before +leaving the interesting studios of which I have been speaking, I ought +to mention a very ingenious application which has been made of a process +called _topogravure_, invented by Commandant de la Noë, who is the +director of this important department. A plate of polished zinc is +coated with bitumen in the usual way, and then exposed directly to the +light under an original drawing, or even under a printed plan. So soon +as the light has sufficiently acted, which may be seen by means of +photometric bands equally transparent at the plate, all the bitumen not +acted upon is dissolved. As it is a positive which has acted as matrix, +the uncovered zinc indicates the design, and the ground remains coated +with insoluble bitumen. The plate is then etched with a weak solution +of nitric acid in water, and the lines of the design are thus slightly +engraved; the surface is then re-coated with another layer of bitumen, +which fills up all the hollows, and is then rubbed down with charcoal. +All the surface is thus cleaned off, and the only bitumen which remains +is that in the lines, which, though not deep, are sufficiently so to +protect the substance from the rubbing of the charcoal. When this +is done we have an engraved plate which can be printed from, like a +lithographic stone; it is gummed and wetted in the usual way, and it +gives prints of much greater delicacy and purity than those taken +directly from the bitumen. The ink is retained by the slight projection +of the surface beyond the line, so that it cannot spread, and a kind of +copper plate engraving is taken by lithographic printing. Besides, in +arriving at this result, there is the advantage of being able to use +directly the original plans and drawings, without being obliged to have +recourse to a plate taken in the camera; the latter is indispensable +for printing in the usual way on bitumen where the impression on the +sensitive film is obtained by means of a negative. It will be seen that +this process is exceedingly ingenious, and not only is its application +very easy, but all its details are essentially practical. + +_Succinate of Iron Developer_.--I have received a letter from M. +Borlinetto, in which he states that he has been induced by the analogy +which exists between oxalic and succinic acids to try whether succinate +of iron can be substituted for oxalate of iron as a developer. To prove +this he prepared some proto-succinate of iron from the succinate of +potassium and proto-sulphate of iron, following the method given by Dr. +Eder for the preparation of his ferrous oxalate developer. He carried +out the development in the same way as is done by the oxalate, and +he found that the succinate of iron is even more energetic than the +oxalate. The plate develops regularly with much delicacy, and gives a +peculiar tone. It is necessary to take some fresh solution at every +operation, on account of the proto-succinate of iron being rapidly +converted into per-succinate by contact with the air. + +_Method of Making Friable Hydro-Cellulose_.--At the meeting of the +Photographic Society of France, M. Girard showed his method of preparing +cellulose in a state of powder, specially adapted for the production of +pyroxyline for making collodion. Carded cotton-wool is placed in water, +acidulated with 3 per cent. of sulphuric or nitric acid, and is left +there from five to fifteen seconds; it is then taken out and laid on a +linen cloth, which is then wrung so as to extract most of the liquid. In +this condition there still remains from 30 to 40 per cent. of acidulated +water; the cotton is divided into parcels and allowed to dry in the open +air until it feels dry to the touch, though in this condition it still +contains 20 per cent. of water. It is next inclosed in a covered jar, +which is heated to a temperature of 65° C.; the desiccation therefore +takes place in the closed space, and the conversion of the material +is completed in about two or three hours. In this way a very perfect +hydro-cellulose is obtained, and in the best form for producing +excellent pyroxyline.--_Corresp. Photo Mews_. + + * * * * * + + + + +PHOTO TRACINGS IN BLACK AND COLOR. + + +Two new processes for taking photo tracings in black and color have +recently been published--"Nigrography" and "Anthrakotype"--both of which +represent a real advance in photographic art. By these two processes we +are enabled for the first time to accomplish the rapid production of +positive copies in black of plans and other line drawings. Each of +these new methods has its own sphere of action; both, therefore, should +deserve equally descriptive notices. + +For large plans, drawn with lines of even breadth, and showing no +gradated lines, or such as shade into gray, the process styled +"nigrography," invented by Itterbeim, of Vienna, and patented both +in Germany and Austria, will be found best adapted. The base of this +process is a solution of gum, with which large sheets of paper can be +more readily coated than with one of gelatine; it is, therefore, very +suitable for the preparation of tracings of the largest size. The paper +used must be the best drawing paper, thoroughly sized, and on this the +solution, consisting of 25 parts of gum arabic dissolved in 100 parts of +water, to which are added 7 parts of potassium bichromate and I part of +alcohol, is spread with a broad, flat brush. It is then dried, and if +placed in a cool, dark place will keep good for a long time. When used, +it is placed under the plan to be reproduced, and exposed to diffused +light for from five to ten minutes--that is to say, to about 14° of +Vogel's photometer; it is then removed and placed for twenty minutes in +cold water, in order to wash out all the chromated gum which has not +been affected by light. By pressing between two sheets of blotting-paper +the water is then got rid of, and if the exposure has been correctly +judged the drawing will appear as dull lines on a shiny ground. After +the paper has been completely dried it is ready for the black color. +This consists of 5 parts of shellac, 100 parts of alcohol, and 15 parts +of finely-powdered vine-black. A sponge is used to distribute the color +over the paper, and the latter is then laid in a 2 to 3 per cent. bath +of sulphuric acid, where it must remain until the black color can be +easily removed by means of a stiff brush. All the lines of the drawing +will then appear in black on a white ground. These nigrographic tracings +are very fine, but they only appear in complete perfection when the +original drawings are perfectly opaque. Half-tone lines, or the marks +of a red pencil on the original, are not reproduced in the nigrographic +copy. + +"Anthrakotype" is a kind of dusting-on process. It was invented by Dr. +Sobacchi, in the year 1879, and has been lately more fully described by +Captain Pizzighelli. This process--called also "Photanthrakography"--is +founded on the property of chromated gelatine which has not been acted +on by light to swell up in lukewarm water, and to become tacky, so that +in this condition it can retain powdered color which had been dusted +on it. Wherever, however, the chromated gelatine has been acted on by +light, the surface becomes horny, undergoes no change in warm water, and +loses all sign of tackiness. In this process absolute opacity in +the lines of the original drawing is by no means necessary, for it +reproduces gray, half-tone lines just as well as it does black ones. +Pencil drawings can also be copied, and in this lies one great advantage +of the process over other photo-tracing methods, for, to a certain +extent, even half-tones can be produced. + +For the paper for anthrakotype an ordinary strong, well-sized paper must +be selected. This must be coated with a gelatine solution (gelatine 1, +water 30 parts), either by floating the paper on the solution, or by +flowing the solution over the paper. In the latter case the paper is +softened by soaking in water, is then pressed on to a glass plate placed +in a horizontal position, the edges are turned up, and the gelatine +solution is poured into the trough thus formed. To sensitize the +paper, it is dipped for a couple of minutes in a solution of potassium +bichromate (1 in 25), then taken out and dried in the dark. + +The paper is now placed beneath the drawing in a copying-frame, and +exposed for several minutes to the light; it is afterward laid in cold +water in order to remove all excess of chromate. A copy of the original +drawing now exists in relief on the swollen gelatine, and, in order to +make this relief sticky, the paper is next dipped for a short time in +water, at a temperature of about 28° or 30° C. It is then laid on a +smooth glass plate, superficially dried by means of blotting-paper, and +lamp-black or soot evenly dusted on over the whole surface by means of +a fine sieve. Although lamp-black is so inexpensive and so easily +obtained, as material it answers the present purpose better than any +other black coloring substance. If now the color be evenly distributed +with a broad brush, the whole surface of the paper will appear to be +thoroughly black. In order to fix the color on the tacky parts of the +gelatine, the paper must next be dried by artificial heat--say, by +placing it near a stove--and this has the advantage of still further +increasing the stickiness of the gelatine in the parts which have not +been acted upon by light, so that the coloring matter adheres even more +firmly to the gelatine. When the paper is thoroughly dry, place it in +water, and let it be played on by a strong jet; this removes all the +color from the parts which have been exposed to the light, and so +develops the picture. By a little gentle friction with a wet sponge, the +development will be materially promoted. + +A highly interesting peculiarity of this anthrakotype process is the +fact that a copy, though it may have been incorrectly exposed, can +still be saved. For instance, if the image does not seem to be vigorous +enough, it can be intensified in the simplest way; it is only necessary +to soak the paper afresh, then dust on more color, etc.; in short, +repeat the developing process as above described. In difficult cases the +dusting-on may be repeated five or six times, till at last the desired +intensity is obtained. + +By this process, therefore, we get a positive copy of a positive +original in black lines on a white ground. Of course, any other coloring +material in a state of powder may be used instead of soot, and then a +colored drawing on a white ground is obtained. Very pretty variations of +the process may be made by using gold or silver paper, and dusting-on +with different colors; or a picture may be taken in gold bronze powder +on a white ground. In this way colored drawings may be taken on a gold +or a silver ground, and very bright photo tracings will be the result. +Some examples of this kind, that have been sent us from Vienna, are +exceedingly beautiful. + +Summing up the respective advantages of the two processes we have above +described, we may say that "nigrography" is best adapted for +copying drawings of a large size; the copies can with difficulty be +distinguished from good autographs, and they do not possess the bad +quality of gelatine papers--the tendency to roll up and crack. Drawings, +however, which have shadow or gradated lines cannot be well produced by +this process; in such cases it is better to adopt "anthrakotype," with +which good results will be obtained.--_Photographic News_. + + * * * * * + + + + +ON M. C. FAURE'S SECONDARY BATTERY. + + +The researches of M. Gaston Planté on the polarization of voltameters +led to his invention of the secondary cell, composed of two strips of +lead immersed in acidulated water. These cells accumulate, and, so to +speak, store up the electricity passed into them from some outside +generator. When the two electrodes are connected with any source of +electricity the surfaces of the two strips of lead undergo certain +modifications. Thus, the positive pole retains oxygen and becomes +covered with a thin coating of peroxide of lead, while the negative pole +becomes reduced to a clean metallic state. + +Now, if the secondary cell is separated from the primary one, we have a +veritable voltaic battery, for the symmetry of the poles is upset, and +one is ready to give up oxygen and the other eager to receive it. When +the poles are connected, an intense electric current is obtained, but +it is of short duration. Such a cell, having half a square meter of +surface, can store up enough electricity to keep a platinum wire 1 +millim. in diameter and 8 centims. long, red-hot for ten minutes. M. +Planté has succeeded in increasing the duration of the current by +alternately charging and discharging the cell, so as alternately to +form layers of reduced metal and peroxide of lead on the surface of the +strip. It was seen that this cell would afford an excellent means for +the conveyance of electricity from place to place, the great drawback, +however, being that the storing capacity was not sufficient as compared +with the weight and size of the cell. This difficulty has now been +overcome by M. Faure; the cell as he has improved it is made in the +following manner: + +The two strips of lead are separately covered with minium or some other +insoluble oxide of lead, then covered with an envelope of felt, firmly +attached by rivets of lead. These two electrodes are then placed near +each other in water acidulated with sulphuric acid, as in the Planté +cell. The cell is then attached to a battery so as to allow a current +of electricity to pass through it, and the minium is thereby reduced to +metallic spongy lead on the negative pole, and oxidized to peroxide of +lead on the positive pole; when the cell is discharged the reduced lead +becomes oxidized, and the peroxide of lead is reduced until the cell +becomes inert. + +The improvement consists, as will be seen, in substituting for strips +of lead masses of spongy lead; for, in the Planté cell, the action is +restricted to the surface, while in Faure's modification the action is +almost unlimited. A battery composed of Faure's cells, and weighing 150 +lb., is capable of storing up a quantity of electricity equivalent to +one horsepower during one hour, and calculations based on facts in +thermal chemistry show that this weight could be greatly decreased. A +battery of 24 cells, each weighing 14 lb., will keep a strip of platinum +five-eighths of an inch wide, one-thirty-second of an inch thick, and 9 +ft. 10 in. long, red-hot for a long time. + +The loss resulting from the charging and discharging of this battery is +not great; for example, if a certain quantity of energy is expended in +charging the cells, 80 per cent. of that energy can be reproduced by the +electricity resulting from the discharge of the cells; moreover, the +battery can be carried from one place to another without injury. A +battery was lately charged in Paris, then taken to Brussels, where it +was used the next day without recharging. The cost is also said to be +very low. A quantity of electricity equal to one horse power during an +hour can be produced, stored, and delivered at any distance within 3 +miles of the works for 1½d. Therefore these batteries may become useful +in producing the electric light in private houses. A 1,250 horsepower +engine, working dynamo-machines giving a continuous current, will in one +hour produce 1,000 horse-power of effective electricity, that is to +say 80 per cent. of the initial force. The cost of the machines, +establishment, and construction will not be more than £40,000, and the +quantity of coal burnt will be 2 lb. per hour per effective horse-power, +which will cost (say) ½d. The apparatus necessary to store up the force +of 1,000 horses for twenty-four hours will cost £48,000, and will weigh +1,500 tons. This price and these weights may become much less after a +time. The expense for wages and repairs will be less than ¼d. per hour +per horse-power, which would be £24 a day, or £8,800 a year; thus the +total cost of one horse-power for an hour stored up at the works is +¾d. Allowing that the carriage will cost as much as the production and +storing, we have what is stated above, viz., that the total cost within +3 miles of the works is 1½d. per horse-power per hour. This quantity of +electricity will produce a light, according to the amount of division, +equivalent to from 5 to 30 gas burners, which is much cheaper than +gas.--_Chemical News_. + + * * * * * + + + + +PHYSICAL SCIENCE IN OUR COMMON SCHOOLS. + +[Footnote: Read before the State Normal Institute at Winona, Minnesota, +April 28, 1881, by Clarence M. Boutelle, Professor of Mathematics and +Physical Science in the State Normal School.] + + +Very little, perhaps, which is new can be said regarding the teaching +of physical science by the experimental method. Special schools for +scientific education, with large and costly laboratories, are by no +means few nor poorly attended; scientific books and periodicals are +widely read; scientific lectures are popular. But, while in many schools +of advanced grade, science is taught in a scientific way, in many others +the work is confined to the mere study of books, and in only a few of +our common district schools is it taught at all. + +I shall advocate, and I believe with good reason, the use of apparatus +and experiments to supplement the knowledge gained from books in schools +where books are used, the giving of lessons to younger children who do +not use books, and the giving of these lessons to some extent in all +our schools. And the facts which I have gathered together regarding the +teaching of science will be used with all these ends in view. + +Physics--using the term in its broadest sense--has been defined as the +science which has for its object the study of the material world, the +phenomena which it presents to us, the laws which govern (or account +for) these phenomena, and the applications which can be made of either +classes of related phenomena, or of laws, to the wants of man. Thus +broadly defined, physics would be one of two great subjects covering the +whole domain of knowledge. The entire world of matter, as distinguished +from the world of mind, would be presented to us in a comprehensive +study of physics. + +I shall consider in this discussion only a limited part of this great +subject. Phenomena modified by the action of the vital force, either in +plants or in animals, will be excluded; I shall not, therefore, consider +such subjects as botany or zoölogy. Geology and related branches will +also be omitted by restricting our study to phenomena which take place +in short, definite, measurable periods of time. And lastly, those +subjects in which, as in astronomy, the phenomena take place beyond +the control of student and teacher, and in which their repetition at +pleasure is impossible, will not be considered. Natural philosophy, or +physics, as this term is generally used, and chemistry, will, therefore, +be the subjects which we will consider as sources from which to draw +matter for lessons for the children in our schools. + +The child's mind has the receptive side, the sensibility, the most +prominent. His senses are alert. He handles and examines objects about +him. He sees more, and he learns more from the seeing, than he will in +later years unless his perceptive powers are definitely trained and +observation made a habit. His judgment and his will are weak. He reasons +imperfectly. He chooses without appropriate motives. He needs the +building up and development given by educational training. _Nature +points out the method._ + +Sensibility being the characteristic of his mind, we must appeal to him +through his senses. We must use the concrete; through it we must act +upon his weak will and immature judgment. From his natural curiosity we +must develop attention. His naturally strong perceptive powers must be +made yet stronger; they must be led in proper directions and fixed upon +appropriate objects. He must be led to appreciate the relation between +cause and effects--to associate together related facts--and to state +what he knows in a definite, clear, and forcible manner. + +Object lessons, conversational lessons, lessons on animals, lessons +based on pictures and other devices, have been used to meet this demand +of the child's mental make up. Good in many respects, and vastly better +than mere book work, they have faults which I shall point out in +connection with the corresponding advantages of easy lessons in the +elements of science. I shall not quibble over definitions. Object +lessons may, perhaps, properly be said to include lessons such as it +seems to me should be given--lessons drawn from natural philosophy or +chemistry--but I use the term here in the sense in which it is often +used, as meaning lessons based upon some object. A thimble, a knife, a +watch, for instance, each of these being a favorite with a certain class +of object teachers, may be taken. + +The objections are: + +1. Little new knowledge can be given which is simple and appropriate. +Most children already know the names of such objects as are chosen, +the names of the most prominent parts, the materials of which they are +composed and their uses. Much that is often given should be omitted +altogether if we fairly regard the economy of the child's time and +mental strength. It doesn't pay to teach children that which isn't worth +remembering, and which we don't care to have them remember. + +2. Study of the qualities of materials is a prominent part of lessons on +objects. Such study is really the study of physical science, but with +objects such as are usually selected is a very difficult part to give +to young children. Ask the student who has taken a course in chemistry +whether the study of the qualities of metals and their alloys is easy +work. Ask him how much can readily be shown, and how much must be taken +on authority. Have him tell you how much or how little the thing itself +suggests, and how much must he memorized from the mere book statement +and with difficulty. Study of materials is good to a certain extent, but +it is often carried much too far. + +Consider a conversational lesson on some animal. Lessons are sometimes +given on cats. As an element in a reading lesson--to arouse interest--to +hold the attention--to secure correct emphasis and inflection--to make +sure of the reading being good: such work is appropriate. But let us see +what the effect upon the pupil is as regards the knowledge he gains +of the cat, and the effect upon his habits of thought and study. The +student gives some statement as to the appearance--the size--or some +act of his cat. It is usually an imperfect statement drawn from the +imperfect memory of an imperfect observation. And the teacher, having +only a _general knowledge_ of the habits of cats, can correct in only +a general way. Thus habits of faulty and incorrect observation and +inaccurate memory are fastened upon the child. It is no less by the +correction of the false than by the presenting of the true, that we +educate properly. + +Besides this there is the fact that traits, habits, and peculiarities +of animals are not always manifested when we wish them to be. Suppose +a teacher asks a child to notice the way in which a dog drinks, for +example; the child may have to wait until long after all the associated +facts, the reasons why this thing was to be observed--the lesson as a +whole of which this formed a part--have all grown dim in the memory, +before the chance for the observation occurs. + +Pictures are less valuable as educational aids than objects; at best +they are but partially and imperfectly concrete. The study of pictures +tends to cultivate the imagination and taste, but observation and +judgment are but little exercised. + +A comparison of the kind of knowledge gained in either of the above ways +with that gained by a study of science as such, will make some of the +advantages of the latter evident. An act of complete knowledge consists +in the identifying of an attribute with a subject. Attributes of +quality--of condition--of relation, may be gained from lessons in which +objects or pictures are used. Attributes of action which are unregulated +by the observer may be learned from the study of animals. But very +little of actions and changes which can be made to take place under +specified conditions, and with uniformity of result, can be learned +until physical science is drawn upon. + +And yet consider the importance of such study. Changes around him appeal +most strongly to the child. "Why _does_ this thing _do_ as it _does_?" +is more frequent than "Why _is_ this thing as it _is_?" He sees changes +of place, of form, of size, of composition, taking place; his curiosity +is aroused; and he is ready to study with avidity, and in a systematic +manner, the changes which his teacher may present to him. Consider +the peculiarities belonging to the study of changes of any sort. The +interest is held, for the mind is constantly gaining the new. The +attention cannot be divided--all parts of the change, all phases of the +action, must be known, and to be known must be _observed_; while in +other forms of lessons the attention may be diverted for a moment to +return to the consideration of exactly what was being observed before. +It goes without saying that in one case quick and accurate observation, +a retentive memory, and the association of causes and effects follow, +and that in the other they do not. + +I advocate, therefore, the teaching of physical science in our +schools--_in all our schools_. Physical science taught by the +experimental method. + +An experiment has been defined as a question put to Nature, a question +asked in _things_ rather than in _words_, and so conditioned that no +uncertain answer can be given. Nature says that all matter gravitates, +not in words, but in the swing of planets around the sun, and in the +leap of the avalanche. And men have devised ingenious machines through +which Nature may tell us the invariable laws of gravitation, and give +some hint as to why it is true. + +There are two kinds of experiments, and two corresponding kinds of +investigators. + +I. In original investigation there are the following elements: + +1. The careful determination of all the conditions under which the +experiment takes place. + +2. The observation of exactly what happens, with a painstaking +elimination of all previous notions as to what ought to happen. + +3. The change of conditions, one at a time, with a comparison of the +results obtained with the changes made, in order to determine that each +condition has been given just its appropriate weight in the experiment. + +4. The classification and explanation of the result. + +5. The extension of the knowledge gained by turning it to investigations +suggested by what has already been learned. + +6. The practical application of the knowledge gained. + +II. In ordinary experiments for educational purposes the experimenter +follows in a general way in the footsteps of the original investigator. +There are the following elements to be considered: + +1. The arrangement of conditions in general imitation of the original +investigator. This arrangement needs only to be general. For example, if +an original investigation were undertaken to determine the composition +of a metallic oxide, the metal and the oxygen would both be carefully +saved to be measured and weighed and fully tested. The ordinary +experiment would be considered successful if oxygen and the metal were +shown to result. + +2. The careful consideration of what should happen. + +3 The determination that the expected either does or does not happen, +with examination of reasons and elimination of disturbing causes in the +latter case. + +4. The accepting as true of the classification and explanation already +given. Theories, explanations, and laws are thus accepted every day by +minds which could never have originated either them or the experiments +from which they were derived. + +The method of original investigation, strictly considered, presents +many difficulties. A long course of preliminary training--a thorough +knowledge of what has been done in a given field already--a quick +imagination--a genius for devising forms of apparatus which will enable +him to work well under particular conditions in the most simple and +effective way--the faculty of suspending judgment, and of seeing +what happens, all that happens, and just how it +happens--patience--caution--courage--quick judgment when a completed +experiment presses for an explanation--these are some of the +characteristics which must belong to the original worker. + +Were we all capable of doing such work there would be these advantages, +among others, of studying for ourselves: + +1. What we find out for ourselves we remember longer and recall more +readily than what we acquire in any other way. This advantage holds true +whether the facts learned are entirely new or only new to us. Almost +every man whose life has been spent in study has a store of facts which +he discovered, and on which he built hopes of future greatness until +he found out later that they were old to the knowledge of the world he +lived in. And these things are among those which will remain longest in +his memory. + +2. Associated facts would be learned in studying in this way which would +remain unknown otherwise. + +But all the advantages would be associated with disadvantages too. Long +periods of time would have to be given for comparatively small results. +The history of science is full of instances in which years were spent in +the elaboration of some law, or principle, or theory which the school +boy of to-day learns in an hour and recites in a breath. Why does water +rise in a pump? Do all bodies, large and small, fall equally fast? The +principles which answer and explain such questions can be made so clear +and evident to the mind of a pupil that he would almost fancy they must +have been known from the first instead of having waited for the hard, +earnest labor of intellectual giants. And science has gone on, and +for us and for our pupils would still go on, only as accompanied with +numerous mistakes and disappointments. + +What method shall we adopt in the teaching of science? It must +differ according to the age and capacity of the pupils. An excellent +modification of the method of original investigation may be arranged as +follows: + +The children are put in possession of all facts relating to conditions, +the teacher explaining them as much as may be necessary. The experiment +is performed, the pupils being required to observe exactly what takes +place, the experiments selected being of such a nature that any previous +judgment as to what ought to occur is as nearly impossible as may be. We +predict from knowledge, real or supposed, of facts which are associated +in our minds with any new subject under consideration. Children often +know in a general, vague, and indefinite way that which, for the sake of +a full and systematic knowledge, we may desire them to study. What +they know will unconsciously modify their expectations, and their +expectations in turn may modify their observations. We are apt to +believe that happens which we expect will happen. There ought to be no +difficulty, however, in finding simple and appropriate experiments with +which the child is entirely unacquainted, and in which anything beyond +the wildest guess work is, for him, impossible. The principal use which +can be made of this method is in the mere observation of what takes +place. Nothing which the child notices correctly need be rejected, +no matter how far removed from the chief event on the object of the +experiment. Care that the pupil shall see all, and separate the +essential from the accidental, is all that is necessary. + +But the original investigator assigns reasons, and with care the +children may be allowed to attempt that. This, however, should not be +carried far; incorrect explanations should be criticised; and the class +should at length be given all the elements of the correct explanation +which they have not determined for themselves. Later, pupils should be +encouraged to name related phenomena, to mention things which they +have seen happen which are due to associated causes, and to suggest +variations for the experiment and tests for its explanation. Good +results may be made to follow this kind of work even with very young +pupils. A child grows in mental strength by using the powers he has, and +mistakes seen to be such are not only steps toward a correct view of the +subject under consideration, but are steps toward that habit of mind +which spontaneously presents correct views at once in study which comes +later in life. + +Another method is this: The pupil may know what is expected to happen, +as well as the conditions given, and held responsible for an observation +of what does happen and a comparison of what he really observes with +what he expects to observe. Explanations are usually given a class, +often in books with which they are furnished, instead of being drawn +from them, in whole or in part, by questioning, when physical science is +studied in this way. Indeed, this method is a necessity when text books +are used, unless experiments from some outside source are introduced. + +Who shall perform the experiments? With young pupils everywhere, and +in most of our common, and even in many of our graded schools, the +experiments must be performed by the teacher. With young pupils the time +is too limited, and the responsibility and necessary care too great to +permit of any other plan being practical. In many of our schools the +small supply of apparatus renders this necessary even with larger +pupils. Added to the reasons already given is the important one that in +no other way--by no other plan--can the teacher be as readily sure that +his pupils observe and reason fully for themselves. In this normal +school a course in physics, in which the experiments are all performed +in the class room by the teacher, is followed by a course in chemistry, +in which the members of the class perform the experiments for themselves +in the laboratory. And, notwithstanding the age, maturity, and previous +observation of the pupils, a great deal must be done both in the +laboratory and in the recitation room to be sure that all that happens +is seen--that the purpose is clearly held in the mind--that the reason +is fully understood. + +With older pupils and greater facilities, however, the experiments +should be performed by the pupils themselves. Constant watchfulness is +necessary, it is true, to insure to the pupil the full educational +value of the experiment. With this watchfulness it can be done, and the +advantages are numerous. Among them are: + +1. The learning of the use and care of apparatus. + +2. The learning of methods of actual construction, from materials at +hand, of some of the simpler kinds of apparatus. + +3. The learning of the importance of careful preparation. An experiment +may be performed in a few minutes before a class which has taken an hour +or more of time in its preparation. The pupil fully appreciates its +importance, and is in the best condition to remember it only when he +has had a part of the hard work attending that preparation. Again, +conditions under which an experiment is successfully performed are often +not appreciated when merely stated in words. "To prepare hydrogen gas, +pass a thistle tube and a delivery tube through a cork which fit tightly +in the neck of a bottle," etc., is simple enough. Let a pupil try with a +cork which does not fit tightly and he will never forget that condition. + +4. The learning of the importance of following directions. Chemistry, +especially, is full of those cases where this means everything. +Sometimes, not often in experiments performed in school, however, it may +mean even life or death. + +The time for experiments should be carefully considered. When performed +by the teacher they should be taken up during the recitation: + +1. If used as a foundation to build upon, at the beginning of the +lesson. + +2. If used as a summary, at the close. + +3. They should be closely connected with the points which they +illustrate. + +4. When very short, or when so difficult as to demand the whole +attention of the teacher, they may be given and afterward discussed. If +long or easy, they may be discussed while the work is going on. Changes +which take place slowly, as those which are brought about by the gradual +action of heat, for instance, are best taken up in this latter way. + +5. Exceptions may be necessary, as when experiments which demand special +preparation immediately before they are presented are given when the +recitation begins, or cases in which experiments are kept until near the +close of a recitation, when the teacher finds that attention flags and +the lesson seems to have lost its interest to the pupils as soon as the +experiments have been given. + +When performed by the pupils themselves, experiments should come before +the recitation as a part of the preparation for the work of the class +room. + +Even in those cases in which the teacher performs the work, opportunity +should be given, from time to time, for the performing of the experiment +by the pupils themselves. This can be done in several ways. During the +course in physics here I am in the habit of leaving apparatus on the +table in my room for at least one day, often for a longer time, and of +giving permission to my class to perform the experiments for themselves +when their time permits and the nature of the experiment makes it an +advantage to get a nearer view than was possible in the class work. I +leave it to them to decide when to perform the experiments, or whether +it is to their advantage to take the time to perform them at all. I make +no attempt to watch either pupils or apparatus, although I would +often assist or explain at intermissions or during the afternoon. The +apparatus was largely used, and the effect on recitations was a good +one. For advanced pupils, and those who can be fully trusted, the plan +is a good one. The only question is the safety of the apparatus; each +teacher can decide for himself regarding the advisability of the plan +for his own school. + +With smaller pupils their own safety may render it best to keep +apparatus out of their hands, except under the immediate direction of +the teacher. With all pupils that is, doubtless, the best plan where +chemicals are concerned. + +Another method is to allow pupils to assist the teacher in the +preparation of experiments, to call occasionally upon members of the +class to come forward and give the experiment in the place of the +teacher, and to encourage home work relating to experiments. This latter +is often spontaneous on the part of older pupils, and can be brought +about with the smaller ones by the use of a little tact; many of the +toys of the present day have some scientific principle at bottom; let +the teacher find out what toys his young pupils have, and encourage them +to use them in a scientific way. + +In whatever ways experiments be used, the class should be made to +consider the following elements as important in every case: + +1. The purpose of the experiment. The same experiment may be performed +at one time for one purpose, at another time for another. The purpose +intended should be made the prominent thing, all others being +subordinated to it. Many chemical reactions, for instance, can be made +to yield either one of two or more substances for study or examination, +or use, while it may be the purpose of the experiment to close only one +of them. + +2 The apparatus. All elements should be considered. The necessary should +be separated from that which may vary. In cases where the various parts +must have some definite relation to the others as regards size or +position, all that should be considered with care. In complex apparatus +the exact office of each part should be understood. + +3. A clear understanding of what happens. To this I have already +referred. + +4. Why it happens. + +5. In what other way it might be made to happen. In chemistry almost +every substance can be prepared in several different ways. The common +method is in most cases made so by some consideration of convenience, +cheapness, or safety. Often only one method is considered in one place +in a text book. In a review, however, several methods can be associated +together. Tests, uses, etc., will vary, too, and should be studied with +that fact in view. In physics phenomena illustrating a given principle +can usually be made to take place in several different ways. Often very +simple apparatus will do to illustrate some fact for which complex and +costly apparatus would be convenient. In such case the study of the +experiment with that fact in view becomes important to us who need to +simplify apparatus as much as possible. + +6. Special precautions which may be necessary. Some experiments always +work well, even in the hands of those not used to the work. Others are +successful--sometimes safe, even--only when the greatest care is taken. +Substances are used constantly in work in chemistry which are deadly +poisons, others which are gaseous and will pass through the smallest +holes. In physics the experiments usually present fewer difficulties of +this sort. But special care is necessary to complete success here. + +7. Other things shown by the experiment. While the main object should +be kept in most prominent view in all experimental work, the fullest +educational value will come only when all that can be learned by the use +of an experiment is carefully considered. + +In selecting just the work to be taken up with a given class of +children, attention must be paid to the selection of the appropriate +matter to be presented and the well adapted method of presenting it. The +following points should be carefully considered: + +1. The matter must be adapted to the capacity of the child. This must be +true both as regards the quality and the quantity. The tendency will be +to teach too much when the matter presented is entirely new, but too +little in many cases where the pupil already knows the subject in a +general way. Matter is valuable only when given slowly enough to permit +of its being fully understood and memorized, while on the other hand +method is valuable only when it secures the development of attention and +the various faculties of the child's mind by presenting a sufficient +amount of the new. + +2. The work must be based on what is already known. This, one of the +best known of the principles of teaching, is of at least as great +importance in physical science as in any other department of knowledge. +It seems to me in many cases to be more important here than elsewhere. +It is not necessary to reach each point by passing over every other +point usually considered. Lessons in electricity or sound, for instance, +can be given to children who have done nothing with other parts of +science. But a natural beginning must be made, and an orderly sequence +of lessons adopted. Children will not do what adults would find almost +impossible in covering gaps between lessons. + +Science may be compared to a great temple. Pillars, each built of many +curiously joined stones, standing at the very entrance, represent the +departments of science so far as man has studied them. We need not dig +down and study the foundations with the children; we need not study +every pillar nor choose any particular one rather than some other; but +we must learn something of every stone--of each great fact--in the +pillar we select, be it ever so little. The original investigator climbs +to stones never before reached, or boldly ventures away into the dim +recesses beyond the entrance to bring back hints of what may be known +and believed a hundred years hence, perhaps. The exact investigator +measures each stone. Patiently and toilsomely scientific men examine +them with glass and reagent. We need not do this, but we must omit none +of the stones. + +3. The work must be continuous. To continue the figure, the stones must +be considered in some regular order. One lesson in electricity, one in +sound, then one in some other department is injurious. We remember best +by associated facts, and, while with the child this is less so than with +the man, one great object of this work is to teach him to remember in +that way. + +4. Experiments should never be performed for mere show. Of two +experiments which illustrate a fact equally well it is often best to +select the most striking and brilliant one. The attention and interest +of the child will be gained in this way when they would not be to so +great an extent in any other. The point of the experiment, however, +should never be lost sight of in attention to the merely wonderful in +it. + +With older pupils, and especially with those who use books for +themselves and perform the experiments there considered, the fact that +experiments demand work, downright hard work, with care, and patience, +and perseverance, and courage, cannot be kept too prominently before +them. + +5. Every lesson should have a definite object. Not the general value of +the experiment, but some _one thing_ which it shows should be the object +considered. + +6. Each experiment should be associated with some truth expressed in +words. The experiment should be remembered in connection with a definite +statement in each case. The memory of either the experiment, or the +principle apart from the experiment, is a species of half knowledge +which should be avoided. An unillustrated principle must, when the +necessity arises, be stored in the memory; and in the systematic study +of books this necessity will often come. But we should never crowd this +abstract work on the memory unassisted by the suggestive concrete, when +the concrete aid is possible. + +7. All that is taught should be true. It is not necessary to attempt to +exhaust a subject, nor to attempt to teach minute details regarding it +to the pupils in our schools, but it is necessary that every statement +given to the pupil to be learned and remembered should contain no +element of falsehood. + +The student in mathematics experiences a feeling of growing strength and +power when he finds, in algebra, that the formula he used in arithmetic +in extracting a square root has grown in importance by leading +indirectly to a theorem of which it is only one particular case--a +theorem with a more definite proof, and a larger capability for use than +he had thought possible. When he finds a still simpler proof for the +binomial theorem in his study of the calculus, his feeling of increasing +power and the desire for still greater results deepens and intensifies. +Were he to find, on the contrary, that from a false notion of the means +to be used in making a thing simple, his teacher in arithmetic had +taught him what is false, we should approve his feeling of disgust and +disappointment. Early impressions are the most lasting, and the hardest +part of school work for the teacher is the unteaching of false ideas, +and the correcting of imperfectly formed and partially understood ideas. +I took a case from mathematics, the exact science, to illustrate this +point. But I must not neglect to notice the difference between that +subject and physical science. The latter consists of theories, +hypotheses, and so-called laws, supported by _observed facts_. The facts +remain, but time has overthrown many of the hypotheses and theories, and +it will doubtless overthrow more and give us something better and truer +in their place. While a careful distinction between what is known and +what is believed is necessary, I should always class the teaching of +accepted theories and hypotheses with the teaching of the true. + +But teachers, with more of imagination than good sense, teach +distinctions which do not exist, generalizations which do not +generalize, and do incalculable mischief by so doing. + +8. Experimental work should be thoroughly honest as to conditions and +results. If an experiment is not the success you expected it would be, +say so honestly, and if you know why, explain it. The pupil should be +taught to know just what _is_, theory or expectation to the contrary +notwithstanding. Discoveries in physical science have often originated +in a search for the reason for some unexpected thing. + +The relation of the study of science to books on science should be +considered. For the work done with pupils before they are given books to +use for themselves, any attempt to follow a text book is to be deplored. +The study of the properties of matter, for instance, would be a fearful +and wonderful thing to set a class of little ones at as a beginning in +scientific work. Just what matter, and force, and molecules, and atoms +are may be well enough for the student who is old enough to begin to use +a book, but they would be but dry husks to a younger child. Many of the +careful classifications and analyses of topics in text books had far +better be used as summaries than in any other way; and a definition is +better when the pupil knows it is true than when he is about to find out +whether it is or not. + +An ideal course in science would be one in which nothing should be +learned but that found out by the observation of the pupil himself under +the guidance of the teacher, necessary terms being given, but only when +the thing to be named had been considered, and the mind demanded the +term because of a felt need. Practically such a method is impossible in +its fullest sense, but a closer approach to it will be an advantage. + +Among the numerous good results which will follow the study of physical +science are the following: + +1. The cultivation of all the faculties of the child in a natural order, +thus making him grow into a ready, quick, and observing man. Education +in schools is too often shaped so as to repress instead of cultivate the +instinctive desire for the _knowledge of things_ which is found in every +child. + +2. The mechanical skill which comes from the preparation and use of +apparatus. + +3. The ability to follow directions. + +4. The belief in stated scientific facts, the understanding of +descriptions, diagrams, etc. + +5. The habitual scientific use of events which happen around us. + +6. The study of the old to find the new. The principle of the telephone, +for instance, is as old as spoken language. The mere[1] pulses in the +air--carrying all the characteristics of what you say--may set in +vibration either the drum of my ear, or a disk of metal. How simple--and +how simple all true science is--when we understand it. + +[Transcribers note 1: corrected from 'more'] + +8. The cultivation of the scientific judgment, and the inventive powers +of the mind. One great original investigator, made such by the direction +given his mind in one of our common schools, would be cheaply bought at +the price of all that the study of science in our schools will cost for +the next quarter of a century. + +8. Honesty. If there is a study whose every tendency is more in the +direction of honesty and truthfulness--both with ourselves and with +others--than is the study of experimental science, I do not know what it +is. + +Physical science, then, will help in making men and women out of our +boys and girls. It is worthy of a fair, earnest trial everywhere. + +A few minutes each day in which a class or a school study science in +some of the ways I have indicated will give a knowledge at the end of a +term or a year of no mean value. The time thus spent will have rested +the pupils from their books, to which they will return refreshed, and +instead of being time lost from other study the work will have been made +enough more earnest and intense to make it again. + +Apparatus for illustrating many of the ordinary facts of physics can be +devised from materials always at hand. Many more can be made by any +one skilled in the use of tools. In chemistry, the simplicity of the +apparatus, and comparative cheapness of ordinary chemicals, make the use +of a large number of beautiful and instructive experiments both easy and +cheap. + +A nation is what its trades and manufactures--its inventions and +discoveries--make it; and these depend on its trained scientific men. +Boys become men. Their growing minds are waiting for what I urge you +to offer. Science has never advanced without carrying practical +civilization with it--but it has never truly advanced save by the use of +the experimental method. _And it never will_. + +Let us then look forward to the time when our boys and young men--our +girls and young women--shall extend the boundaries of human knowledge by +its use, fitted so to do by what we may have done for them. + + * * * * * + + + + +GEOGRAPHICAL SOCIETY OF THE PACIFIC. + + +This society is a recent organization, the objects of which are to +encourage geographical exploration and discovery; to investigate and +disseminate geographical information by discussion, lectures, and +publications; to establish in this, the chief maritime city of the +Western States, for the benefit of commerce, navigation, and the +industrial and material interests of the Pacific slope, a place where +the means will be afforded of obtaining accurate information not only of +the countries bordering on the Pacific ocean, but of every part of the +habitable globe; to accumulate a library of the best books on geography, +history, and statistics; to make a collection of the most recent maps +and charts--especially those which relate to the Pacific coast, the +islands of the Pacific and the Pacific ocean--and to enter into +correspondence with scientific and learned societies whose objects +include or sympathize with geography. + +The society will publish a bulletin and an annual journal, which will +interchange with geographical and other societies. Monthly meetings are +to be held, at which original papers will be read or lectures be +given; and to which, as well as to the entertainments to distinguished +travelers, to the conversazioni, and to the informal evenings, the +fellows of the society will have the privilege of introducing their +friends. The initiation fee to the society is $10; monthly dues $1; life +fellowship $100. + +At a meeting held at the Palace Hotel on the 12th May, the following +gentlemen were elected for the ensuing year: President, Geo. Davidson; +Vice-Presidents, Hon. Ogden Hoffman, Wm. Lane Booker, H.B.M. Consul, and +John R. Jarboe; Foreign Corresponding Sec., Francis Berton; Home Cor. +Sec., James P. Cox; Treas., Gen. C. I. Hutchinson; Sec'y, C. Mitchell +Grant, F.R.G.S. The council is composed of the following: Hon. Joseph W. +Winans, Hon. J.F. Sullivan, Ralph C. Harrison, A.S. Hallidie, Thos. E. +Stevin, F.A.G.S., W.W. Crane, Jr., W.J. Shaw, C.P. Murphy, Thos. Brice, +Edward L.G. Steele, Gerrit L. Lansing, Joseph D. Redding. The Trustees +are Geo. Davidson, Wm. Lane Booker, Hon. Jno. S. Hager, Geo. Chismore, +M.D., Selim Franklin. + + * * * * * + + + + +THE BEHRING'S STRAITS CURRENTS. + + +It will be remembered that a short time since we mentioned the fact that +W.H. Dall, of the U. S. Coast Survey, who has passed a number of years +in Alaskan waters, on Coast Survey duty, denied the existence of any +branch of the Kuro Shiwo, or Japanese warm stream, in Behring's Straits. +That is, he failed to find evidence of the existence of any such +current, although he had made careful observations. At the islands in +Behring's Straits, his vessel had sailed in opposite directions with ebb +and flood tide, and he thought the only currents there were tidal in +their nature. The existence or non-existence of this current is an +important point in Arctic research on this side of the continent. + +At the last meeting of the Academy of Sciences, Prof. Davidson, of the +U. S. Coast Survey, author of the "Alaska Coast Pilot," refuted Dr. +Dall's opinion of the non-existence of a branch of the Kuro Shiwo, or +Japanese warm stream, from the north Pacific into the Arctic Ocean, +through Behring's Straits. He said that in 1857 he gave to the Academy +his own observations, and recently he had conferred with Capt. C.L. +Hooper, who commanded the U. S. steamer Thomas Corwin, employed as a +revenue steam cruiser in the Arctic and around the coast of Alaska. +Capt. Hooper confirms the opinions of all previous navigators, every one +of which, except Dr. Dall, say that a branch of this warm stream passed +northward into the Arctic through Behring's Strait. It is partly +deflected by St. Lawrence Island, and closely follows the coast on the +Alaskan side, while a cold current comes out south, past East Cape +in Siberia, skirting the Asiatic shore past Kamschatka, and thence +continues down the coast of China. He said ice often extended several +miles seaward, from East Cape on the Asiatic side of Behring Strait, +making what seamen call a false cape, and indicating cold water, while +no such formation makes off on the American side, where the water is +12 degrees warmer than on the Asiatic shore off the Diomede islands, +situated in the middle of Behring's Strait, the current varies in +intensity according to the wind. + +Frequently it is almost nothing for several days, when after a series of +southerly winds the shallow Arctic basin has been filled, under a heavy +pressure, with an unusual volume of water, and a sudden change to +northerly winds, makes even a small current setting southward for a few +days, just as at times the surface currents set out our Golden Gate +continuously for 24 and 48 hours, as shown by the United States Coast +Survey tide gauges. Whalers report that the incoming water then flows +in, under the temporary outflowing stream. + +Old trees, of a variety known to grow in tropical Japan, are floated +into the Arctic basin as far as past Point Barrow, on the American side, +but none are found on the Asiatic side, or near Wrangell Land, where a +cold stream exists, and ice remains late in the season. On the northern +side of the Aleutian islands are found cocoanut husks and other tropical +productions stranded along the beaches. The American coast of Alaska +has a much warmer climate than the Asiatic coast of Siberia, and the +American timber line extends very far north. The ice opens early in the +season on the American side, and invariably late on the Asiatic. + +Capt. C. L. Hooper says that when just north of Behring's Strait, off +the American coast, in the Arctic basin, the U.S. steamer Thomas Corwin, +when becalmed for 24 hours, drifted 40 miles to the northward. From +all these, and other facts, and the unanimous testimony of American +whalemen, who have for years spent many months annually in the Arctic, +and from his own observations, he argued that a branch of the Kuro-Shiwo +or Japanese warm stream, unquestionably runs northward through Behring's +Strait into the Arctic basin along the northwestern coast of Alaska. + +Prof. Davidson then called to mind the testimony in regard to the +existence of Plover Island, between Herald Island and Wrangell Land, +which he said was first made public through this academy. The evidence +of Capts. Williams and Thomas Long were recited and highly praised. One +of the officers of Admiral Rodgers' expedition climbed to near the top +of Herald Island, at a time of great refraction, when probably a false +horizon existed, and hence did not see Plover Island, although Wrangell +Land was in sight. + +Prof. Davidson thinks all the authorities are against Dr. Dall, who +attributes the warm current he observed on the American coast to water +from the Yukon River and to the large expanse of shallow water exposed +to the sun's rays. As Dall's observations only covered a few days of +possibly exceptional weather, and the whalers and Captain Hooper's cover +vastly longer periods, and whalers all say it is a pretty hard thing to +beat southward through Behring's Strait, owing to the northerly current +setting into the Arctic, we are forced to the conclusion that Dr. +Dall has mistaken the exception for the rule, and his conclusions are +therefore erroneous. When, in 1824, Wrangell went north, he, like +others, always found broken ice and considerable open water. In 1867, +when Capt. Thomas Long made his memorable survey of the coast of +Wrangell Land, the season was an exceptionally open one, and in +California we had heavy rains, extending into July. + + * * * * * + + + + +EXPERIMENTAL GEOLOGY. + +ARTIFICIAL PRODUCTION OF CALCAREOUS PISOLITES AND OOLITES. + + +Mr. Stanislas Meunier communicates to _Le Nature_ an account of some +interesting specimens of globular calcareous matter, resembling +pisolites or peastones both in appearance and structure, which were +accidentally formed as follows: The Northern Railway Company, France, +desiring to purify some calciferous water designed for use in steam +boilers, hit upon the ingenious expedient of treating it with lime water +whose concentration was calculated exactly from the amount of lime +held in the liquid to be purified. The liquids were mixed in a vast +reservoir, to which they were led by parallel pipes, and by which they +were given a rapid eddying motion. The transformation of the +bicarbonate into neutral carbonate of lime being thus effected with +the accompaniment of a circling motion, the insoluble salt which +precipitated, instead of being deposited in an amorphous state, hardened +into globules, the sizes of which were strictly regulated by the +velocity of the currents. Those that have been formed at one and the +same operation are uniform, but those formed at different times vary +greatly--their diameters varying by at least one millimeter to one and +a half centimeters. The surface of the smaller globules is smooth, but +that of the larger ones is rough. Even by the naked eye, it may be +seen that both the large and small globules are formed of regularly +superposed concentric layers. If an extremely thin section be made +through one of them it is found that the number of layers is very great +and that they are remarkably regular (A). By the microscope, it has been +ascertained that each layer is about 0.007 of a millimeter in thickness. + +On observing it under polarized light the calcareous substance is +discovered to be everywhere crystallized, and this suggests the question +whether the carbonate has here taken the form of aragonite or of +calcite. Examination has shown it to be the latter. The density of the +globules (2.58) is similar to that of ordinary varieties of calcite. It +is probable that if the operation were to take place under the influence +of heat, under the conditions above mentioned, aragonite would be +formed. It is hardly necessary to dwell upon the possible geological +applications of this mode of forming calcareous oolites and pisolites. + + +ON CRYSTALS OF ANHYDROUS LIME. + +Some time ago it was discovered that some limestone, which had been +submitted for eighteen months to a heat of nearly 1,000 degrees in +the smelting furnaces of Leroy-Descloges (France), had given rise to +perfectly crystallized anhydrous lime. Figure C shows three of these +crystals magnified 300 diameters. It will be noticed that they have a +striking analogy with grains of common salt. They are, in fact, cubes +(often imperfect), but do not polarize light, as a substance of the +first crystalline system should. However, it is rarely the case that the +crystals do not have _some_ action on light. Most usually, when the two +Nicol prisms are crossed so as to cause extinction, the crystals present +the appearance shown at D. That is to say, while the central portion +is totally inactive there are seen on the margins zones which greatly +brighten the light. + +[Illustration] + +A and B.--Calcareous Pisolites and Oolites produced artificially. +A.--External aspect and section of a Pisolite. B.--Details of internal +structure as seen by the microscope. + +C and D.--Crystals of anhydrous Lime obtained artificially. C.--Crystals +seen under the microscope in the natural light. D.--Crystals seen under +the microscope in polarized light. + +The phenomenon is explained by the slow carbonization of the anhydrous +lime under the influence of the air; the external layers passing to the +state of carbonate of lime or Iceland spar, which, as well known, has +great influence on polarized light. This transformation, which takes +place without disturbing the crystalline state, does not lead to any +general modification of the form of the crystals, and the final product +of carbonization is a cubic form known in mineralogical language as +_epigene_. As the molecule of spar is entirely different in form +from the molecule of lime, the form of the crystal is not absolutely +preserved, and there are observed on the edges of the epigene crystal +certain grooves which correspond with a loss of substance. These grooves +are quite visible, for example, on the crystal to the left in Fig. D. + +Up to the present time anhydrous lime has been known only in an +amorphous state. The experiment which has produced it in the form noted +above would doubtless give rise to crystallized states of other earthy +oxides likewise, and even of alkalino-earthy oxides. + + + + +COCCIDÆ. + +[Footnote: A paper recently read before the California Academy of +Sciences.] + +By DR. H. BEHR. + + +With the exception of Hymenoptera there is no group of insects that +interfere in so many ways in good and evil with our own interests, as +that group of Homoptera called Coccidæ. + +But while the Hymenoptera command our respect by an intellect that +approaches the human, the Coccus tribe possesses only the lowest kind of +instinct, and its females even pass the greater part of their lives in +a mere vegetation state, without the power of locomotion or perception, +like a plant, exhibiting only organs of assimilation and reproduction. + +But strange to say, these two groups, otherwise so very dissimilar, +exhibit again a resemblance in their product. Both produce honey and +wax. + +It is true, the honey of this tribe is almost exclusively used by the +ants. But I have tasted the honey-like secretion of an Australian +lecanium living; on the leaves of Eucalyptus dumosus; and the manna +mentioned in Scripture is considered the secretion of Coccus manniparus +(Ehrenberg) that feeds on a tamarix, and whose product is still used by +the native tribes round Mount Sinai. + +Several species of Coccides are used for the production of wax; many +more, among which the Cochenill, for dyes. + +All these substances can be obtained in other ways, even the Cochenill +is to a great extent superseded by aniline dyes, but in regard to one +production, indispensable to a great extent, we are entirely dependent +on some insects of this family; it is the Shellac, lately also found in +the desert regions around the Gila and Colorado on the Larrea Mexicana. +You will remember that excellent treatise on this variety of Shellac, +written by Professor J.M. Stillman at Berkeley, on its chemical +peculiarities. + +But all these different forms of utility fall very lightly in weight, +and can not even be counted as an extenuating circumstance, when we +compare them to the enormous evils brought on farmer and gardener by the +hosts of those Coccides that visit plantations, hothouses, and orchards. + +To combat successfully against these insect-pests we have first to study +their habits and then adapt to them our remedies, which you will see +are more effective when well administered than those which we possess +against insect pests of other classes. + +I give here only the outlines of their natural history, peculiarities +that are common to all, for it would be impossible to go into detail. +Where there are exceptions of practical importance I will mention them. + +In countries with a well defined winter the winged males appear as +soon as white frosts are no more usual, and copulate with the unwieldy +limbless female, that looks more like a gall or morbid excrescence, than +a living animal. Shortly after the young ones are perceptible near the +withered body of their mother, covered by waxy secretions that look +somewhat like a feathery down. + +These young ones are lively enough, they move about with agility, and +it is not till high summer that they fasten themselves permanently, and +lose feet and antennae, organs of locomotion and perception that are no +more of any use to them. (There is a slight difference in this regard +between different genera, as for instance, Coccus and Dorthesia retain +these organs in different degrees of imperfection, Lecanium and +Aspidiotus losing every trace of them.) + +In this limbless, senseless state the females remain fall and winter. +Toward the end of winter these animated galls begin to swell, and those +containing males enter the state of the chrysalis, from which the males +emerge at the beginning of the warm season and fecundate the gall-like +females, which undergo neither chrysalis state nor any other change, but +die, or we may call it dissolve into their offspring, for there scarcely +remains anything of them, except a pruinous kind of down, after having +given birth to the young ones. + +Now we come to the practical deduction from these facts. It is clear +that the only time when the scalebug can emigrate and infest a new +tree is the time when it is a larva, that is, when it has the power of +locomotion. In countries with a pronounced winter this time begins +much later than with us, but it ends about the same time, that is, the +beginning of August. I have seen the male of Aspidiotus in February, so +that the active larva may be expected in March, and the active Lecanium +Hesperidum I have seen last year, June 27, at Colonel Hooper's ranch in +Sonoma County. We may safely fix the time of the active scalebug from +March to August. + +Notwithstanding the agility of the young scalebug, the voyage from one +tree to another, considering the minute size of the traveler, is an +undertaking but seldom succeeding, but one female bug, if we take +into account its enormous fertility, is sufficient to cover with its +grandchildren next year a tree of moderate size. + +Besides there is another and much more effective way of transmigration +by the kind assistance of the ant who colonizes the scalebug as well for +its wax as it colonizes the Aphis for its honey. Birds on their feathers +and the gardener himself on his dress contribute to spread them. + +But even the ant can not transplant the scalebug when it is once firmly +fixed by its rostrum. + +It is evident, therefore, that the time for the application of +insecticides is the time when all the scalebugs are fixed, that is about +the end of July or beginning of August. All previous application will +clean the tree or plant only for a time, and does not prevent a more or +less numerous immigration from the neighboring vegetation, especially if +an ant-hill is not far off. + +As to the insecticide, there are to be applied two very effective ones, +each with its advantages and disadvantages. + +1. Petroleum and its different preparations. + +2. Lye or soap. + +The petroleum is the best disinfectant. It can safely be applied to any +cutting or stem, as long as it is not planted, but is one of the most +invidious substances when applied to vegetation in the garden, or +fields. If effectively applied, it can not be prevented from running +down the bark of the tree and entering the ground, where every drop +binds a certain amount of earth to an insoluble substance, in which +state it remains for ever. With every application the quantity of these +insoluble compounds is augmented and sterility added. + +If I am not mistaken, it was near Antwerp--at least I am certain it was +in Belgium--where the first experience of this kind is recorded. + +In France, preparations of coal tar have been recommended and have +been lately used in the form of a paint. May be that in this form the +substance is not so apt to enter into combinations with the soil. At any +rate, the method is of too recent a date to permit any conclusions about +the final result of these applications, as the invidious nature of the +substance produces, by gradual accumulation, its effects, which are not +perceived until they are irreparable. + +2. Lye or soap. The application of these insecticides requires more +care, and is therefore more troublesome. But instead of attracting +fertility from the soil, they add to it. In Southern Europe soap +and water has been for many years the remedy against the Lecanium +Hesperidum. The method applied by the farmers in Portugal, as described +to me by Dr. Bleasdale, is perhaps the most perfect one. The Portuguese +have very well observed that the colonization of scalebugs always begins +at the lowest end of the trunk and pretend, therefore, that the scalebug +comes out of the ground. This, of course, is not the case, but may their +interpretation be an error, they have been practical enough in utilizing +their observation about the invasion beginning near the roots. They +knead a ring of clay round the tree, in which ring the soap water runs +when they wash the tree, and besides, they fill frequently the little +ditch formed by this ring. + +This arrangement of course is only possible in climates of a rainy +summer. + +As it is our object to make our knowledge as available as possible for +practical purposes, I repeat for the benefit of cultivators the advice, +without repeating the reasoning: + +1. Use the petroleum for disinfecting imported trees and cuttings: + +2. Use soap for cleaning trees planted in your orchard. + +3. If you must use the petroleum in your garden, use it in August, when +a single application is sufficient. + + * * * * * + + + + +AGRICULTURAL ITEMS. + + +The exportation of dried apples from this country to France has greatly +increased of late years, and now it is said that a large part of this +useful product comes back in the shape of Normandy cider and light +claret. + +A.B. Goodsell says in the _New York Tribune_: "Put your hen feed around +the currants. I did this twice a week during May and June, and not a +currant worm was seen, while every leaf was eaten off other bushes 150 +feet distant, and not so treated." + +Buckwheat may be made profitable upon a piece of rough or newly cleared +ground: No other crop is so effective in mellowing rough, cloddy land. +The seed in northern localities should be sown before July 12; otherwise +early frosts may catch the crops. Grass and clover may sometimes be sown +successfully with buckwheat. + +The London News says: "Of all poultry breeding, the rearing of the goose +in favorable situations is said to be the least troublesome and most +profitable. It is not surprising, therefore, that the trade has of late +years been enormously developed. Geese will live, and, to a certain +extent, thrive on the coarsest of grasses." + +When a cow has a depraved appetite, and chews coarse, indigestible +things, or licks the ground, it indicates indigestion, and she should +have some physic. Give one pint and a half of linseed oil, one pound of +Epsom salts, and afterward give in some bran one ounce of salt and the +same of ground ginger twice a week. + +Asiatic breeds of fowl lay eggs from deep chocolate through every shade +of coffee color, while the Spanish, Hamburg, and Italian breeds are +known for the pure white of the eggshell. A cross, however remote, with +Asiatics, will cause even the last-named breeds to lay an egg slightly +tinted. + +In setting out currant bushes care should be exercised not to place any +buds under ground, or they will push out as so many suckers. Currants +are great feeders, and should be highly manured. To destroy the worm, +steep one table-spoonful of hellebore in a pint of water, and sprinkle +the bushes. Two or three sprinklings are sufficient for one season. + +Mr. Joseph Harris, of Rochester, makes a handy box for protecting melons +and cucumbers from insect enemies. Take two strips of board of the +required size, and fasten them together with a piece of muslin, so the +muslin will form the top and two sides of the box. Then stretch into +box form by inserting a small strip of wood as a brace between the two +boards. This makes a good, serviceable box, and, when done with for the +season, it can be packed into a very small space, by simply removing the +brace and bringing the two board sides together. As there is no patent +on the contrivance, anybody can make the boxes for himself. + +Mr. C. S. Read recently said before the London Fanners' Club: "American +agriculturists get up earlier, are better educated, breed their stock +more scientifically, use more machinery, and generally bring more +brains to bear upon their work than the English farmer. The practical +conclusion is, that if farmers in England worked hard, lived frugally, +were clad as meanly as those of the States, were content to drink filthy +tea three times a day, read more and hunted less, the majority of them +may continue to live in the old country."--_N. E. Farmer_. + + * * * * * + + + + +TIMBER TREES. + + +A paper was read by Sir R. Christison at the last meeting of the +Edinburgh Botanical Society upon the "Growth of Wood in 1880." In a +former paper, he said, he endeavored to show that, in the unfavorable +season of 1879, the growth of wood of all kinds of trees was materially +less than in the comparatively favorable season of 1878. He had now to +state results of measurements of the same trees for the recent favorable +season of 1880. The previous autumn was unfavorable for the ripening of +young wood, and the trees in an unprepared condition were exposed during +a great part of December, 1879, to an asperity of climate unprecedented +in this latitude. This might have led one to expect a falling off in the +growth of wood, and it appeared, from comparison of measurements, that, +with very few exceptions, the growth of wood last year was even more +below the average of favorable years than that of the bad year, 1879. +Thus, in fifteen leaf-shedding trees of various species, exclusive of +the oak, the average growth of trunk girth in three successive years +was: 1878, 8-10ths; 1879, 45-100ths; 1880, 3-10ths and a half. In +four specimens of the oak tribe, the growth was: 1878, 8-10ths; 1879, +77-100ths; 1880, 54-100ths. In twenty specimens of the evergreen +Pinaceae the growth was: 1878, 8-10ths; 1879, 7-10ths; 1880, 6-10ths and +a half. After giving details in regard to particular trees, Sir Robert +stated, as general deductions from his observations, that leaf-shedding +trees, exclusive of the oak, suffered most; that the evergreen Pinaceae +suffered least; and that there was some power of resistance on the part +of the oak tribe which was remarkable, the power of resistance of the +Hungary oak being particularly deserving of attention. In another +communication on the "extent of the season of growth," Sir Robert +stated, as the result of observations on five leaf-shedding and five +evergreen trees, that in the case of the former, even in a fine year, +the growth of wood was confined very nearly, if not entirely, to the +months of June, July, and August; while in the case of the latter growth +commenced a month sooner, terminating, however, about the same time. Mr. +A. Buchan said it was proposed that the inquiry should be taken up more +extensively over Scotland. + + * * * * * + +MEDICAL USES OF FIGS.--Prof. Bouchut speaks (_Comptes Rendus_) of some +experiments he has made, going to show that the milky juice of the +fig-tree possesses a digestive power. He also observed that, when some +of this preparation was mixed with animal tissue, it preserved it +it from decay for a long time. This fact, in connection with Prof. +Billroth's case of cancer of the breast, which was so excessively foul +smelling that all his deodorizers failed, but which, on applying a +poultice made of dried figs cooked in milk, the previously unbearable +odor was entirely done away with, gives an importance to this homely +remedy not to be denied.--_Medical Press and Circ._ + + * * * * * + + + + +BLOOD RAIN. + + +The sensibilities of ignorant or superstitious people have at various +times been alarmed by the different phenomena of so-called blood, ink, +or sulphur rains. Ehrenberg very patiently collected records of the most +prominent instances of these, and published them in his treatise on the +dust of trade winds. Some, it is known, are due to soot; others, to +pollen of conifers or willows; others, to the production of fungi and +algae. + +Many of the tales of the descent of showers of blood from the clouds +which are so common in old chronicles, depends, says Mr. Berkeley, the +mycologist, upon the multitudinous production of infusorial insects or +some of the lower algae. To this category belongs the phenomenon known +under the name of "red snow." One of the most peculiar and remarkable +form, which is apparently virulent only in very hot seasons, is caused +by the rapid production of little blood-red spots on cooked vegetables +or decaying fungi, so that provisions which were dressed only the +previous day are covered with a bright scarlet coat, which sometimes +penetrates deeply into their substance. This depends upon the growth of +a little plant which has been referred to the algae, under the name +of _Palmellae prodigiosa_. The rapidity with which this little plant +spreads over meat and vegetables is quite astonishing, making them +appear precisely as if spotted with arterial blood; and what increases +the illusion is, that there are little detached specks, exactly as if +they had been squirted from a small artery. The particles of which the +substance is composed have an active molecular motion, but the morphosis +of the production has not yet been properly observed. The color of the +so-called "blood rain" is so beautiful that attempts have been made +to use it as a dye, and with some success; and could the plant be +reproduced with any constancy, there seems little doubt that the color +would stand. On the same paste with the "blood-rain" there have been +observed white, blue, and yellow spots, which were not distinguishable +in structure and character. + + * * * * * + + + + +TOPICAL MEDICATION IN PHTHISIS. + + +Dr. G.H. Mackenzie reports in the _Lancet_ an acute case of phthisis +which was successfully treated by him by causing the patient to respire +as continuously as possible, through a respirator devised for the +purpose, an antiseptic atmosphere. The result obtained appears to bear +out the experiments of Schüller of Greifswald, who found that animals +rendered artificially tuberculous were cured by being made to inhale +creosote water for lengthened periods. Intermittent spraying or inhaling +does not produce the same result. In order to insure success the +application to the lungs must be made _continuously_. For this purpose +Dr. Mackenzie has used various volatile antiseptics, such as creosote, +carbolic acid, and thymol. The latter, however, he has discarded +as being too irritating and inefficient. Carbolic acid seems to be +absorbed, for it has been detected freely in the urine after it had been +inhaled; but this does not happen with creosote. As absorption of the +particular drug employed is not necessary, and therefore not to be +desired, Dr. Mackenzie now uses creosote only, either pure or dissolved +in one to three parts of rectified spirits. "Whether," says he, "the +success so far attained is due to the antidotal action of creosote and +carbolic acid on a specific tubercular neoplasm, or to their action as +preventives of septic poisoning from the local center in the lungs, +it is certain that their continuous, steady use in the manner just +described has a decidedly curative action in acute phthisis, and is +therefore, worthy of an extended trial." + + * * * * * + + + + +ON THE LAW OF AVOGADRO AND AMPERE. + + +The Scientific American Supplement of May 14,1881, contains, under this +head, Mr. Wm. H. Greene's objections to my demonstration (in No. 270 +of the same paper) of the error of Avogadro's hypothesis. The most +important part of my argument is based on the evidence afforded by the +compound cyanogen; and Mr. Greene, directing his attention to this +subject in the first place, states that because cyanogen combines +with hydrogen or with chlorine, without diminution of volumes, I have +concluded that the hypothesis falls to the ground. This statement has +impressed me with the conviction that Mr. Greene has failed to perceive +the difficulty which is at the bottom of the question, and I will, +therefore, present the subject more fully and comprehensively. + +The molecule of any elementary body is, on the ground of the hypothesis, +assumed to be a compound of two atoms, and the molecule of carbon +consequently C_2=24; that of nitrogen N_2=28. Combination of the two, +according to the same hypothesis, takes place by substitution; the +atoms are supposed to be set free and to exchange places, forming a +new compound different from the original only in this: that each new +particle contains an atom of each of the two different substances, while +each original particle consists of two identical atoms. The product is, +therefore, assumed to be, and can, under the circumstances, be no other +than particles of the composition CN and weight 26. These particles are +molecules, according to the definition laid down, just as C_2 and N_2; +but there is this essential difference, that the specific gravity of +cyanogen gas, 26, coincides with the molecular weight, while the assumed +molecular weight, N_2=28, is twice as great as the specific gravity of +the gas, N=14. + +In using the term molecular weight, it is to be remembered that it does +not express the weight of single molecules, but only their relative +weight, millions of millions molecules being contained in the unit of +volume. But on the hypothesis that there is the same number of molecules +in the same volume of any gas, the specific gravities of gases can be, +and are, identified with their molecular weights, and, on the ground of +the hypothesis again, the unit of the numbers which enter into every +chemical reaction and constitute the molecular weight, is stipulated to +be that contained in two volumes. + +The impossibility of the correctness of the hypothesis is now revealed +by the fact just demonstrated, that in the case of nitrogen the specific +gravity does not coincide with the molecular weight. If equal volumes +contain the same number of molecules, the specific gravities and the +molecular weights must be the same; and if the specific gravities and +molecular weights are not the same, equal volumes cannot contain the +same number of molecules. The assumed molecular weight of nitrogen is +twice as great as the specific gravity, but the molecular weight and +the specific gravity of cyanogen are identical; the number of molecules +contained in one volume of cyanogen must, therefore, necessarily be +twice as great as the number contained in one of nitrogen, and this is +fully and completely borne out by the chemical facts. + +In saying that when cyanogen combines with chlorine there is naturally +no condensation, Mr. Greene has no idea that this natural law is fatal +to his artificial law of Avogadro and Ampere; "for," continues he, "the +theory is fulfilled by the actual reaction." It is not. The theory +requires two vols. of cyanogen and two vols. of chlorine, that is, the +unit of numbers, to enter into reaction and to produce two vols. of +the compound. But they produce four vols., and the non-condensation is +therefore in opposition to the theory. It is true beyond doubt that the +molecular weight of cyanogen chloride is contained in two volumes, in +spite of the hypothesis, not on the ground of it; two vols. + two vols., +producing four vols.; two vols. could, theoretically, contain only half +the unit of numbers, and there seems to be no escape from the following +general conclusions: + +1. Two vols. of CNCl, representing the unit of numbers, the constituent +weights, C=12, N=14, Cl=35.5, must each, likewise, represent the same +number; the molecular weight is, therefore, contained in one vol. of N +or Cl, but in two of CNCl and equal numbers are not contained in equal +volumes. + +2. The weights N=14, Cl=35.5 occupy in the free state one volume, but +in the combination, CNCl, two volumes; their specific gravity is, +therefore, by chemical action reduced to one half. The fact thus +elicited of the variability and variation of the specific gravity is of +fundamental importance and involves the irrelevancy of the mathematical +demonstration of the hypothesis. In this demonstration the specific +gravity is assumed to be constant, and this assumption not holding good, +and the number of molecules in unit of volume being reduced to one half +when the specific gravity is reduced to the same extent by chemical +action, it is obvious that the mathematical proof must fail. Mr. Greene +states that I have proceeded to demolish C. Clerk Maxwell's conclusion +from mathematical reasoning. This is incorrect; I have found no fault +with the conclusion of the celebrated mathematician, and consider his +reasoning unimpeachable. I am also of opinion that he is entitled to +great credit and respect for the prominent part he has taken in the +development of the kinetic theory, and further think that it was for +the chemists to produce the fact of the variability of the specific +gravities, which they would probably not have failed to do but for the +prevalence of Avogadro's hypothesis, which is virtually the assertion of +the constancy of the specific gravities. + +3. The unit of numbers being represented by Cl=35.5, it is likewise +represented by H=1, and as the product of the union of the two elements +is HCl, 36.5 = two vols., combination takes place by addition and not by +substitution; consequently are + +4. The elementary molecules not compounds of atoms? And the distinction +between atoms and molecules is an artificial one, not justified by the +natural facts. + +5. Is the molecular weight not in every instance = two volumes? + +These conclusions overthrow all the fundamental assumptions on which the +hypothesis rests, and leave it, in the full meaning of the term, without +support. Though Mr. Greene states that my arguments are based upon +entirely erroneous premises, he has not even attempted to invalidate a +single one of my premises. + +As he considers the non-condensation to be natural in the case of +cyanogen and chlorine, the condensation of two vols. of HCl + two vols. +of H_3N to two vols. of NH_4Cl ought to appear to him unnatural. He, +however, contends for it, and tries, on this solitary occasion, to +strengthen his opinion by authority, though the proof, if it could be +given, that ammonium chloride at the temperature of volatilization is +decomposed into its two constituents, would be insufficient to uphold +the theory. + +The ground on which Mr. Greene assumes a partial decomposition at 350° +C. is the slight excess of the observed density (14.43) over that +corresponding to four vols. (13.375). There is, however, a similar +slight excess in the case of the vapor of ammonium cyanide, the same +values being respectively 11.4 and 11; and as this compound is volatile +at 100° C and, at the same time, is capable to exist at a very high +temperature, being formed by the union of carbon with ammonia, nobody +has ever, as far as I am aware, maintained that it is completely or +partially decomposed at volatilization. The excess of weight not being +due, therefore, to such cause in this case, it cannot be due to it in +the other. + +The question being whether the molecular weight of ammonium chloride +is two vols. or four vols., an idea of the magnitude of the assumed +decomposition is conveyed by the proportion of the volume of the +decomposed salt to the volume of the non-decomposed, and Mr. Greene's +quotation of the percentage of weight is irrelevant and misleading, and +his number not even correct. A mixture containing + + 1.055 vols. of spec. gr. 26.75 = 28.22 and + 12.32 " " " " 13.375 = 164.78 + ------ ------ + 13.375 " 193 + +has the spec. gr. 193 / 13.375 = 14.43. The proportion in one vol. of +the undecomposed to the decomposed salt is, therefore, as 1 to 11.68 and +the percentage of volume of the former 0.0789, and that of weight 28.22 +/ 193 = 0.146, and not 0.16. + +It is not easy to imagine why a small fraction of the heavy molecules +should be volatilized undecomposed, the temperature being sufficient +to decompose the great bulk. Marignac assumes, indeed, partial +decomposition, but the difficulties which he encountered in making the +experiments, on the results of which his opinion rests, were so great +that he himself accords to the numbers obtained by him only the value of +a rough approximation. + +The heat absorbed in volatilization will comprise the heat of +combination as well as of aggregation, if decomposition takes place, and +will therefore be the same as that set free at combination. Favre and +Silbermann found this to be 743.5 at ordinary temperature, from which +Marignac concludes that it would be 715 for the temperature 350°; he +found as the heat of volatilization 706, but considers the probable +exact value to be between 617 and 818.[1] + +[Footnote 1: See _Comptes Rendus_, t. lxvii., p. 877.] + +An uncertainty within so wide a range does not justify the confidence +of Mr. Greene which he expresses in these words: "It is, therefore, +extremely probable that ammonium chloride is almost entirely +dissociated, even at the temperature of volatilization." By Boettinger's +apparatus a decomposition may possibly have been demonstrated, but it +remains to be seen whether it is not due to some special cause. + +When Mr. Greene says that the relations between the physical properties +of solids and liquids and their molecular composition can in no +manner affect the laws of gases, nobody is likely to dissent; but the +conclusion that their discussion is foreign to the question of the +number of molecules in unit of volume does by no means follow. If the +specific gravity of a solid or the weight of unit of volume represents +a certain number of molecules, and is found to occupy two volumes in a +compound of the solid with another solid, the number of molecules in one +volume is reduced to one half. This I have shown to be the case in a +number of compounds, and the decrease of the specific gravity with +increase of the complexity of composition appears to be a general law, +as may be concluded from the very low specific gravity of the most +highly organized compounds, for instance the fatty bodies, the molecules +of which, being composed of very many constituents, are of heavy weight; +and likewise the compounds which occur in combination with water and +without it, the simpler compound having invariably a greater specific +gravity than the one combined with water; for instance: + + BaH_2O_2 sp. gr. 4.495 + " " + 8H_2O " 1.656 + S_2H_2O_2 " 3.625 + " " + 8H_2O " 1.396 + FeSO_4 " 3.138 + " + 7H_2O " 1.857 + +and so in every other case. This is now a recurrence of what takes +place in gases, and proves the fallacy of the hypothesis; for if these +compounds could be volatilized the vapor densities would necessarily +vary in the inverse proportion of the degree of composition. + +The reproach that Berthelot has been endeavoring for nearly a quarter of +a century to hold back the progress of scientific chemistry, is a great +and unjustifiable misrepresentation of the distinguished chemist +and member of the Institute of France, who has done so much for +thermo-chemistry, and the more unfortunate as it seems to serve only the +purpose of a prelude to the following sentences: "But Mr. Vogel cannot +claim, as can Mr. Berthelot, any real work or experiment, however +roughly performed, suggested by the desire to prove the truth of his +own views. Let him not, then, bring forth old and long since explained +discrepancies, ... but when he will have discovered new or overlooked +facts ... chemists will gladly listen." ... Mr. Greene is here no longer +occupied to investigate whether what I have said concerning Avogadro's +hypothesis is true or false, but with myself he has become personal, and +in noticing his remarks my sole object is to contend against an error +which is much prevalent. If, according to Mr. Greene, the real work of +science consists in experimenting, and conclusions unsupported by our +own experiments have no value, it does not appear for what purpose he +has published his answer to my paper; an experiment of his, settling +Marignac's uncertain results, would have justified the reliance he +places on them. The ground he takes is utterly untenable. Experiments +are necessary to establish facts; without them there could be no +science, and the highest credit is due to those who perform successfully +difficult or costly experiments. Experimenting is, however, not the +aim and object of science, but the means to arrive at the truth; and +discoveries derived from accumulated and generally accepted facts are +not the less valuable on account of not having been derived from new and +special experiment. + +It is, further, far from true that the real work of science consists +in experimenting; mental work is not less required, and the greatest +results have not been obtained by experimenters, but by the mental labor +of those who have, from the study of established facts, arrived at +conclusions which the experimenters had failed to draw. This is +naturally so, because a great generalization must explain all the facts +involved, and can be derived only from their study; but the attention +of the experimenter is necessarily absorbed by the special work he +undertakes. I refer to the three greatest events in science: the +discovery of the Copernican system, the three laws of Kepler, and +Newton's law of gravitation, none of which is due to direct and special +experimentation. Copernicus was an astronomer, but the discovery of his +system is due chiefly to his study of the complications of the Ptolemaic +system. Kepler is a memorable witness of what can be accomplished by +skillful and persistent mental labor. "His discoveries were secrets +extorted from nature by the most profound and laborious research." The +discovery of his third law is said to have occupied him seventeen years. +Newton's great discovery is likewise the result of mental labor; he was +enabled to accomplish it by means of the laws of Kepler, the laws of +falling bodies established by Galileo, and Picard's exact measurement of +a degree of a meridian. + +If, then, mental work is as indispensable as experimental, it is not +less true that there are men more specially fitted for the one, others +for the other, and the best interests of science will be served when +experiments are made by those specially adapted, skillful, and favorably +situated, and the possibly greatest number of men, able and willing to +do mental work, engage in extracting from the accumulated treasures of +experimental science all the results which they are capable to yield. +Any truth discovered by this means is clear gain, and saves the waste +of time, labor, and money spent in unnecessary experiment. Mr. Greene's +zeal for experiment and depreciation of mental work would be in order, +if ways and means were to be found to render the advancement of science +as difficult and slow as possible; they are decidedly not in the +interest of science, and can not have been inspired by a desire for its +promotion. + +As the evidence of the specific heats of the fallacy of Avogadro's +hypothesis involves lengthy explanations, the subject is reserved for +another paper. + +San Francisco, Cal., May, 1881. + +E. VOGEL. + + * * * * * + + + + +DYEING REDS WITH ARTIFICIAL ALIZARIN. + +By M. MAURICE PRUD'HOMME. + + +Since several years, the methods of madder dyeing have undergone a +complete revolution, the origin of which we will seek to point out. When +artificial alizarin, thanks to the beautiful researches of Graebe and +Liebermann, made its industrial appearance in 1869, it was soon found +that the commercial product, though yielding beautiful purples, was +incapable of producing brilliant reds (C. Koechlin). While admitting +that the new product was identical with the alizarin extracted from +madder, we were led to conclude that in order to produce fine Turkey +reds, the coloring matters which accompany alizarin must play an +important part. This was the idea propounded by Kuhlmann as far back as +1828 (_Soc. Ind. de Mulhouse_, 49, p. 86). According to the researches +of MM. Schützenberger and Schiffert, the coloring matters of madder +are alizarin, purpurin, pseudopurpurin, purpuroxanthin, and an orange +matter, which M. Rosenstiehl considers identical with hydrated purpurin. +Subsequently, there have been added to the list an orange body, +purpuroxantho-carbonic acid of Schunck and Roemer, identical with the +munjistin found by Stenhouse in the madder of India. It was known +that purpuroxanthin does not dye; that pseudopurpurin is very easily +transformed into purpurin, and the uncertainty which was felt concerning +hydrated purpurin left room merely for the hypothesis that Turkey-red +is obtained by the concurrent action of alizarin and purpurin. In the +meantime, the manufacture of artificial alizarin became extended, and a +compound was sold as "alizarin for reds." It is now known, thanks to the +researches of Perkin, Schunck, Roemer, Graebe, and Liebermann, that in +the manufacture of artificial alizarin there are produced three distinct +coloring matters--alizarin, iso or anthrapurpurin, and flavopurpurin, +the two latter being isomers of purpurin. We may remark that purpurin +has not been obtained by direct synthesis. M. de Lalande has produced +it by the oxidation of alizarin. Alizarin is derived from +monosulphanthraquinonic acid, on melting with the hydrate of potassa or +soda. It is a dioxyanthraquinone. + +Anthrapurpurin and flavopurpurin are obtained from two isomeric +disulphanthraquinonic acids, improperly named isoanthraflavic and +anthraflavic acids, which are converted into anthrapurpurin and +flavopurpurin by a more profound action of potassa. These two bodies are +trioxyanthraquinones. + +We call to mind that alizarin dyes reds of a violet tone, free from +yellow; roses with a blue cast and beautiful purples. Anthrapurpurin and +flavopurpurin differ little from each other, though the shades dyed +with the latter are more yellow. The reds produced with these coloring +matters have a very bright yellowish reflection, but the roses are too +yellow and the purples incline to a dull gray. + +Experience with the madder colors shows that a mixture of alizarin and +purpurin yields the most beautiful roses in the steam style, but it is +not the same in dyeing, where the roses got with fleur de garance have +never been equaled. + +"Alizarins for reds" all contain more or less of alizarin properly +so-called, from 1 to 10 per cent., along with anthrapurpurin and +flavopurpurin. This proportion does not affect the tone of the reds +obtained further than by preventing them by having too yellow a tone. + +The first use of the alizarins for reds was for application of styles, +that is colors containing at once the mordant and the coloring matter +and fixed upon the cloth by the action of steam. Good steam-reds were +easily obtained by using receipts originally designed for extracts of +madder (mixtures of alizarin and purpurin). On the other hand, the first +attempts at dyeing red grounds and red pieces were not successful. The +custom of dyeing up to a brown with fleur and then lightening the shade +by a succession of soapings and cleanings had much to do with this +failure. Goods, mordanted with alumina and dyed with alizarin for reds +up to saturation, never reach the brown tone given by fleur or garancin. +This tone is due in great part to the presence of fawn colored matters, +which the cleanings and soapings served to destroy or remove. The same +operations have also another end--to transform the purpurin into its +hydrate, which is brighter and more solid. The shade, in a word, loses +in depth and gains in brightness. With alizarins for reds, the case is +quite different; they contain no impurities to remove and no bodies +which may gain brightness in consequence of chemical changes under the +influence of the clearings and soapings. These have only one result, in +addition to the formation of a lake of fatty acid, that is to make the +shades lose in intensity. The method of subjecting reds got up with +alizarin to the same treatment as madder-reds was faulty. + +There appeared next a method of dyeing bases upon different +principles. The work of M. Schützenberger (1864) speaks of the use of +sulpho-conjugated fatty acids for the fixation of aniline colors. In +England, for a number of years, dyed-reds had been padded in soap-baths +and afterwards steamed to brighten the red. In 1867, Braun and Cordier, +of Rouen, exhibited Turkey reds dyed in five days. The pieces were +passed through aluminate of soda at 18° B., then through ammonium +chloride, washed, dyed with garancin, taken through an oil-bath, dried +and steamed for an hour, and were finally cleared in the ordinary manner +for Turkey-reds. The oil-bath was prepared by treating olive-oil with +nitric acid. This preparation, invented by Hirn, was applied since 1846 +by Braun (Braun and Cordier). Since 1849, Gros, Roman, and Marozeau, +of Wesserling, printed fine furniture styles by block upon pieces +previously taken through sulpholeic acid. When the pieces were steamed +and washed the reds and roses were superior to the old dyed reds and +roses produced at the cost of many sourings and soapings. Certain makers +of aniline colors sold mixtures ready prepared for printing which were +known to contain sulpholeic acids. There was thus an idea in the air +that sulpholeic acid, under the influence of steam, formed brilliant and +solid lakes with coloring matters. These facts detract in nothing from +the merit of M. Horace Koechlin, who combined these scattered data +into a true discovery. The original process may be summed up under the +following heads: Printing or padding with an aluminous mordant, which is +fixed and cleaned in the usual manner; dyeing in alizarin for reds with +addition of calcium acetate; padding in sulpholeic acid and drying; +steaming and soaping. The process was next introduced into England, +whence it returned with the following modifications; in place of +olive-oil or oleic acid, castor oil was used, as cheaper, and the number +of operations was reduced. Castor oil, modified by sulphuric acid, can +be introduced at once into the dye-beck, so that the fixation of the +coloring matter as the lake of a fatty acid is effected in a single +operation. The dyeing was then followed by steaming and soaping. + +For red on white grounds and for red grounds, a mordant of red liquor at +5° to 6° B. is printed on, with a little salt of tin or nitro-muriate of +tin. It is fixed by oxidation at 30° to 35° C., and dunged with cow-dung +and chalk. The pieces are then dyed with 1 part alizarin for reds at 10 +per cent., ¼ to ½ oil for reds (containing 50 per cent.), 1-6th part +acetate of lime at 15° B., giving an hour at 70° and half an hour at the +same heat. Wash, pad in oil (50 to 100 grms. per liter of water), dry on +the drum, or better, in the hot flue, and steam for three-quarters to an +hour and a half. The padding in oil is needless, if sufficient oil has +been used in dyeing, and the pieces may be at once dried and steamed. +Wash and soap for three-quarters of an hour at 60°. Give a second +soaping if necessary. If there is no fear of soiling the whites, dye at +a boil for the last half-hour, which is in part equal to steaming. + +Red pieces and yarns may be dyed by the process just given for red +grounds; or, prepare in neutral red oil, in the proportion of 150 grms. +per liter of water for pieces and 15 kilos for 100 kilos of yarns. For +pieces, pad with an ordinary machine with rollers covered with +calico. Dry the pieces in the drum, and the yarn in the stove. Steam +three-quarters of an hour at 1½ atmosphere. Mordant in pyrolignite of +alumina at 10° B., and wash thoroughly. Dye for an hour at 70°, and half +an hour longer at the same heat, using for 100 kilos of cloth or yarn 20 +kilos alizarin at 10 per cent., 10 kilos acetate of lime at 18° B., and +5 kilos sulpholeic acid. Steam for an hour. Soap for a longer or shorter +time, with or without the addition of soda crystals. There may be added +to the aluminous mordant a little salt of tin to raise the tone. Lastly, +aluminate of soda may be used as a mordant in place of red liquor or +sulphate of alumina. + +Certain firms employ a so-called continuous process. The pieces are +passed into a cistern 6 meters long and fitted with rollers. This +dye-bath contains, from 3 to 5 grms. of alizarin per liter of water, and +is heated to 98°. The pieces take 5 minutes to traverse this cistern, +and, owing to the high temperature and the concentration of the dye +liquor, they come out perfectly dyed. Two pieces may even be passed +through at once, one above the other. As the dye-bath becomes exhausted, +it must be recruited from time to time with fresh quantities of +alizarin. The great advantage of this method is that it economizes not +merely time but coloring matter. + +The quantity of acetate of lime to be employed in dyeing varies with the +composition of the mordant and with that of the water. Schlumberger has +shown that Turkey-red contains 4 molecules of alumina to 3 of lime. +Rosenstiehl has shown that alumina mordants are properly saturated if +two equivalents of lime are used for each equivalent of alizarin, if the +dyeing is done without oil. These figures require to be modified when +the oil is put into the dye beck, as it precipitates the lime. Acetate +of lime at 15° B., obtained by saturating acetic acid with chalk and +adding a slight excess of acetic acid, contains about ¼ mol. acetate of +lime.--_Bulletin de la Société Chimique de Paris._ + + * * * * * + + + + +THE SCIENTIFIC AMERICAN SUPPLEMENT. + +PUBLISHED WEEKLY. + +TERMS OF SUBSCRIPTION, $5 A YEAR. + + +Sent by mail, postage prepaid, to subscribers in any part of the United +States or Canada. Six dollars a year, sent, prepaid, to any foreign +country. + +All the back numbers of THE SUPPLEMENT, from the commencement, January +1, 1876, can be had. 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