Matter Soluble Fixedin Air Tannin| || Matter Solu- || ble in Alcohol || | |Moisture | | Gelatine |--+-- --+-- --+-- --+-- --+--Steer hide, hemlock tanned (heavy leather) 10.95 4.15 19.77 39.1 26.03Sheepskins, sumac " (Hungarian) 10.8 10.3 12.1 40.3 26.5Finished calf, pine bark tanned (Hungarian) 11.2 1.7 7.4 41.6 38.1Steer hide, quebracho tanned (heavy leather) 11.7 1.6 11.2 43.1 32.4" " chestnut " " " 13.5 0.29 1.99 45.46 38.76Finished calfskins,oak tanned (Chateau Renault) 12.4 0.33 3.59 46.74 36.94Steer hide, laurel tanned (heavy leather) 12.4 1.05 7.95 47.47 31.13" " oak tanned after three years inthe 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 255.7Sumac 248.1Pine 240.3Quebracho 232Chestnut 219.9Oak 213.9Laurel 210.6Oak, 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 64.2Sumac 61.4Pine 90.8Quebracho 75.3Chestnut 85.2Oak 76.9Laurel 64.8Oak, 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 10.88Sumac 60.4 39.6 11Pine bark 52.5 47.5 9.56Quebracho 57.1 42.9 10.4Chestnut 53.97 46.03 9.79Oak 55.87 44.13 10.24Laurel 60.4 39.6 10.94Oak, 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.
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.
SUGGESTIONS IN ARCHITECTURE--NEW HIGH SCHOOL, OXFORD
SUGGESTIONS IN ARCHITECTURE--NEW HIGH SCHOOL, OXFORD
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.
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 gramsPyrogallic 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 calledtopogravure, 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.
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.
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.
[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 ageneral knowledgeof 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. "Whydoesthis thingdoas itdoes?" is more frequent than "Whyisthis thing as itis?" 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 beobserved; 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 inthingsrather than inwords, 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 someone thingwhich 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 byobserved 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 whatis, 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 theknowledge of thingswhich 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.