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SCIENTIFIC AMERICAN SUPPLEMENT NO. 303
NEW YORK, OCTOBER 22, 1881
Scientific American Supplement. Vol. XII, No. 303.
Scientific American established 1845
Scientific American Supplement, $5 a year.
Scientific American and Supplement, $7 a year.
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TABLE OF CONTENTS
I. ENGINEERING AND MECHANICS.—New Eighty-ton Steam Hammer at the Saint Chamond Works, France.—7 figures.—Elevation of hammer.—Profile— Transverse section.—Profile view of foundation, etc.—Plan of plant.—General plan of the forging mill.—Details of truss and support for the cranes.
Great Steamers.—Comparative details of the Servia, the City of Rome, the Alaska, and the Great Eastern.
Improved Road Locomotive.—2 figures.—Side and end views
American Milling Methods. By ALBERT HOPPIN.—Ten years' progress.—Low milling.—Half high milling.—High milling.—Important paper read before the Pennsylvania State Millers' Association.
Machine for Dotting Tulles and other Light Fabrics.—3 figures.
II. TECHNOLOGY AND CHEMISTRY.—The Reproduction and Multiplication of Negatives. By ERNEST EDWARDS.
A New Method of Making Gelatine Emulsion. By W. K. BURTON.
The Pottery and Porcelain Industries of Japan.
Crystallization Table.
The Principles of Hop Analysis. By Dr. G. O. CECH.
Water Gas.—A description of apparatus for producing cheap gas, and some notes on the economical effects of using such gas with gas motors, etc.—By J. EMERSON DOWSON.
On the Fluid Density of Certain Metals. By Professors CHANDLER ROBERTS and T. WRIGLESON.
III. PHYSICS, ELECTRICITY, ETC.—Electric Power.—The nature and uses of electricity.—Electricity vs. steam.
On the Method of Obtaining and Measuring Very High Vacua with a Modified Form of Sprengel Pump. By Prof OGDEN N. ROOD.—4 figures.— Apparatus for obtaining vacua of one four hundred-millionth of an atmosphere—Construction.—Manipulation.—Calculations.—Results
IV. ART, ARCHITECTURE, ETC.—Old Wrought Iron Gates, Guildhall. Worcester, England. 1 figure.
The French Crystal Palace, Park of St. Cloud, Paris. 1 full page illustration.
Suggestions in Architecture. A Castellated Chateau. Perspective and plan. Chateau in the gean Sea.
V. HYGIENE AND MEDICINE.—Hydrophobia Prevented by Vaccination.
On Diptera as Spreaders of Disease. By J. W. SLATER.
On the Relations of Minute Organisms to Certain Specific Diseases.
VI. ASTRONOMY—The Centenary of the Discovery of Uranus. By F. W. DENNING. 2 figures. Approximate place of Uranus among the stars at its discovery, March l3, 1871.—Orbits of the Uranian Satellites.
VII. BIOLOGY, ETC.—The Varying Susceptibility of Plants and Animals to Poisons and Disease.
Kind Treatment of Horses.
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NEW EIGHTY TON STEAM HAMMER AT THE SAINT CHAMOND WORKS
Ever since the improvements that have been introduced into the manufacture of steel, and especially into the erection of works for its production, have made it possible to obtain this metal in very large masses, it has necessarily been preferred to iron for all pieces of large dimensions, inasmuch as it possesses in the highest degree that homogeneousness and resistance which are so difficult to obtain in the latter metal. It has consequently been found necessary to construct engines sufficiently powerful to effect the forging of enormous ingots, as well as special furnaces for heating them and apparatus for manipulating and transporting them.
The greatest efforts in this direction have been made with a view to supplying the wants of heavy artillery and of naval constructions; and to these efforts is metallurgy indebted for the creation of establishments on a scale that no one would have dared a few years ago to think of. The forging mill which we are about to describe is one of those creations which is destined to remain for a long time yet very rare; and one which is fully able to respond, not only to all present exigencies, but also, as far as can be foreseen, to all those that may arise for a long period to come. The mill is constructed as a portion of the vast works that the Compagnie des Forges et Aciries de la Marine own at Saint Chamond, and which embrace likewise a powerful steel works that furnishes, especially, large ingots exceeding 100 tons in weight.
The mill consists, altogether, of three hammers, located in the same room, and being of unequal powers in order to respond to different requirements. The largest of these hammers is of 80 tons weight, and the other two weigh respectively 35 and 28 tons. Each of them has a corresponding furnace for heating by gas, as well as cranes for maneuvering the ingots and the different engines. The general plan view in Fig. 4 shows the arrangement of the hammers, cranes, and furnaces in the millhouse.
The gas generators which supply the gas-furnaces are located out of doors, as are the steam-generators. The ingots are brought from the steel factory, and the forged pieces are taken away, by special trucks running on a system of rails. We shall now give the most important details in regard to the different parts of the works.
The Mill-House—This consists of a central room, 262 feet long, 98 feet wide, and 68 feet in height, with two lean-to annexes of 16 feet each, making the total width 100 feet. The structure is wholly of metal, and is so arranged as to permit of advantage being taken of every foot of space under cover. For this purpose the system of construction without tie-beams, known as the "De Dion type," has been adopted. Fig. 1 gives a general view of one of the trusses, and Fig. 5 shows some further details. The binding-rafters consist of four angle-irons connected by cross-bars of flat iron. The covering of corrugated galvanized iron rests directly upon the binding-rafters, the upper parts of which are covered with wood for the attachment of the corrugated metal. The spacing of these rafters is calculated according to the length of the sheets of corrugated iron, thus dispensing with the use of ordinary rafters, and making a roof which is at once very light and very durable, and consequently very economical. Rain falling on the roof flows into leaden gutters, from whence it is carried by leaders into a subterranean drain. The vertical walls of the structure are likewise of corrugated iron, and the general aspect of the building is very original and very satisfactory.
The 80 Ton Hammer—The three hammers, notwithstanding their difference in power, present similar arrangements, and scarcely vary except in dimensions. We shall confine ourselves here to a description of the 80 ton apparatus. This consists, in addition to the hammer, properly so called, of three cranes of 120 tons each, serving to maneuver the pieces to be forged, and of a fourth of 75 tons for maneuvering the working implements. These four cranes are arranged symmetrically around the hammer, and are supported at their upper extremity by metallic stays. Besides the foregoing there are three gas furnaces for heating the ingots. Figs. 1, 2, and 3 show the general arrangement of the apparatus.
Foundations of the Hammer and Composition of the Anvil-Bed—To obtain a foundation for the hammer an excavation was made to a depth of 26 feet until a bed of solid rock was reached, and upon this there was then spread a thick layer of beton, and upon this again there was placed a bed of dressed stones in the part that was to receive the anvil-stock and hammer.
On this base of dressed stones there was placed a bed formed of logs of heartwood of oak squaring 16 inches by 3 feet in height, standing upright, joined together very perfectly, and kept in close juxtaposition by a double band of iron straps joined by bolts. The object of this wooden bed was to deaden, in a great measure, the effect of the shock transmitted by the anvil-stock.
NEW EIGHTY-TON STEAM HAMMER AT THE ST CHAMOND WORKS.
The Anvil-Stock.—The anvil-stock, which is pyramidal in shape, and the total weight of which amounts to 500 tons, is composed of superposed courses, each formed of one or two blocks of cast iron. Each course and every contact was very carefully planed in order to make sure of a perfect fitting of the parts; and all the different blocks were connected by means of mortises, by hot bandaging, and by joints with key-pieces, in such a way as to effect a perfect solidity of the parts and to make the whole compact and impossible to get out of shape.
The anvil-stock was afterwards surrounded by a filling-in of masonry composed of rag-stones and a mortar made of cement and hydraulic lime. This masonry also forms the foundation for the standards of the hammer, and is capped with dressed stone to receive the bed-plates.
The Power-Hammer (Figs. A and B).—The power-hammer, properly so-called, consists, in addition to the hammer-head, of two standards to whose inner sides are bolted guides upon which slides the moving mass. The bed-plates of cast iron are 28 inches thick, and are independent of the anvil-stock. They are set into the bed of dressed stone capping the foundation, and are connected together by bars of iron and affixed to the masonry by foundation bolts. To these bedplates are affixed the standards by means of bolts and keys. The two standards are connected together by iron plates four inches in thickness, which are set into the metal and bolted to it so as to secure the utmost strength and solidity. The platform which connects the upper extremities of the standards supports the steam cylinder and the apparatus for distributing the steam. The latter consists of a throttle valve, twelve inches in diameter, and an eduction valve eighteen inches in diameter, the maneuvering of which is done by means of rods extending down to a platform upon which the engineman stands. This platform is so situated that all orders can be distinctly heard by the engineman, and so that he shall be protected from the heat radiated by the steel that is being forged. All the maneuvers of the hammers are effected with most wonderful facility and with the greatest precision.
The piston is of cast-steel, and the rod is of iron, 12 inches in diameter. The waste steam is carried out of the mill by a pipe, and, before being allowed to escape into the atmosphere, is directed into an expansion pipe which it penetrates from bottom to top. Here a portion of the water condenses and flows off, and the steam then escapes into the open air with a greatly diminished pressure. The object of this arrangement is to diminish to a considerable extent the shocks and disagreeable noise that would be produced by the direct escape of the steam at quite a high pressure and also to avoid the fall of condensed water.
The following are a few details regarding the construction of the hammer:
Total height of foundations........... 26 ft. From the ground to the platform ...... 28 "
Platform .............................. 3.25 " Height of cylinder.................... 21 "
Total height...................... 78.25 ft.
Weight of anvil-stock................ 500 tons. Weight of bed-plates................. 122 " Weight of standards.................. 270 " Weight of platform and cylinder...... 148 " Piston, valves, engineman's platform, hammer, etc........................ 160 "
Total weight................... 1,200 tons.
Weight of the hammer.................. 80 tons. Maximum fall.......................... 25.75 ft. Distance apart of the standards....... 21.6 " Width of hammer....................... 6 " Pressure of steam..................... 16 lb. Effective pressure to lift 80 tons.... 7 " Description of Figures.—A, the 80-ton hammer; B, B1, B2, cranes; C, C1, C2, supports of cranes; D, D1, D2, gas furnaces; A1, the 35-ton hammer; A2, the 28-ton hammer; EE, railways; F, engineman's platform; G, lever for maneuvering the throttle valve; H, an ingot being forged.
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GREAT STEAMERS.
The Brooklyn Eagle gives a very interesting description of the three new steamships now almost completed and shortly to be placed in the New York and Liverpool trade by the Cunard, Inman, and Williams and Guion lines. The writer has prepared a table comparing the three vessels with each other and with the Great Eastern, the only ship of greater dimensions ever built. We give as much of the article as our space will allow, and regret that we have not the room to give it entire:
Line. Cunard. Inman. Guion. Admiralty. Vessel. Servia City of Rome. Alaska. Great[1]
Length 530 feet. 546 feet. 520 feet. 679 feet. Breadth 52 feet. 52 ft. 3 in. 50 ft. 6 in. 82 feet. Depth 44 ft. 9 in. 37 feet. 38 feet. 60 feet. Gross ton'ge 8,500 8,300 8,000 13,344[2] Horse pow'r 10,500 10,000 11,000 2,600 Speed 17 knots. 18 knots. 18 knots. 14 knots. Sal'n pas- 320 and 52 sengers. 450 300 2d class Steerage 600 1,500 1,000 Where Clydeb'nk Barrow in Clyde, built. Thomson Furness Elder Date of sailing. October 22 October 13 November 5
[Footnote 1: To be sold at auction soon.]
[Footnote 2: Net register.]
In 1870 the total tonnage of British steam shipping was 1,111,375; the returns for the year 1876 showed an increase to 2,150,302 tons, and from that time to the present it has been increasing still more rapidly. But, as can be seen from the above table, not only has the total tonnage increased to this enormous extent, but an immense advance has been made in increasing the size of vessels. The reason for this is, that it has been found that where speed is required, along with large cargo and passenger accommodation, a vessel of large dimensions is necessary, and will give what is required with the least proportionate first cost as well as working cost. Up to the present time the Inman line possessed, in the City of Berlin, of 5,491 tons, the vessel of largest tonnage in existence. Now, however, the Berlin is surpassed by the City of Rome by nearly 3,000 tons, and the latter is less, by 200 tons, than the Servia, of the Cunard line. It will be observed, too, that while there is not much difference between the three vessels in point of length, the depth of the Alaska and the City of Rome, respectively, is only 38 feet and 37 feet, that of the Servia is nearly 45 feet as compared with that of the Great Eastern of 60 feet. This makes the Servia, proportionately, the deepest ship of all. All three vessels are built of steel. This metal was chosen not only because of its greater strength as against iron, but also because it is more ductile and the advantage of less weight is gained, as will be seen when it is mentioned that the Servia, if built of iron, would have weighed 620 tons more than she does of steel, and would have entailed the drawback of a corresponding increase in draught of water. As regards rig, the three vessels have each a different style. The Cunard Company have adhered to their special rig—three masts, bark rigged—believing it to be more ship shape than the practice of fitting up masts according to the length of the ship. On these masts there is a good spread of canvas to assist in propelling the ship. The City of Rome is rigged with four masts; and here the handsome full-ship rig of the Inman line has been adhered to, with the addition of the fore and aft rigged jigger mast, rendered necessary by the enormous length of the vessel. It will be seen that the distinctive type of the Inman line has not been departed from in respect to the old fashioned but still handsome profile, with clipper bow, figurehead, and bowsprit—which latter makes the Rome's length over all 600 feet. For the figurehead has been chosen a full length figure of one of the Roman Csars, in the imperial purple. Altogether, the City of Rome is the most imposing and beautiful sight that can be seen on the water. The Alaska has also four masts, but only two crossed.
The length of the City of Rome, as compared with breadth, insures long and easy lines for the high speed required; and the depth of hold being only 37 feet, as compared with the beam of 52 feet, insures great stability and the consequent comfort of the passengers. A point calling for special notice is the large number of separate compartments formed by water tight bulkheads, each extending to the main deck. The largest of these compartments is only about 60 feet long; and, supposing that from collision or some other cause, one of these was filled with water, the trim of the vessel would not be materially affected. With a view to giving still further safety in the event of collision or stranding, the boilers are arranged in two boiler rooms, entirely separated from each other by means of a water tight iron bulkhead. This reduces what, in nearly all full-powered steamships, is a vast single compartment, into two of moderate size, 60 feet in length; and in the event of either boiler room being flooded, it still leaves the vessel with half her boiler power available, giving a speed of from thirteen to fourteen knots per hour. The vessel's decks are of iron, covered with teak planking; while the whole of the deck houses, with turtle decks and other erections on the upper deck, are of iron, to stand the strains of an Atlantic winter. Steam is supplied by eight cylindrical tubular boilers, fired from both ends, each of the boilers being 19 feet long and having 14 feet mean diameter. There are in all forty eight furnaces. The internal arrangements are of the finest description. There are two smoking rooms, and in the after deckhouse is a deck saloon for ladies, which is fitted up in the most elegant manner, and will prevent the necessity of going below in showery weather. At the sides of the hurricane deck are carried twelve life boats, one of which is fitted as a steam launch. The upper saloon or drawing-room is 100 feet long, the height between decks being 9 feet. The grand dining-saloon is 52 feet long, 52 feet wide, and 9 feet high, or 17 feet in the way of the large opening to the drawing-room above. This opening is surmounted by a skylight, and forms a very effective and elegant relief to the otherwise flat and heavy ceiling. There are three large and fourteen small dining tables, the large tables being arranged longitudinally in the central part of the saloon, and the small tables at right angles on the sides. Each diner has his own revolving arm chair, and accommodation is provided for 250 persons at once. A large American organ is fixed at the fore end of the room, and opening off through double spring doors at the foot of the grand staircase is a handsome American luncheon bar, with the usual fittings. On each side of the vessel, from the saloon to the after end of the engine room, are placed staterooms providing for 300 passengers. The arrangements for steerage passengers are of a superior description. The berths are arranged in single tiers or half rooms, not double, as is usually the custom, each being separated by a passage, and having a large side light, thus adding greatly to the light, ventilation, and comfort of the steerage passengers, and necessitating the advantage of a smaller number of persons in each room. The City of Rome is the first of the two due here; she sails from Liverpool on October 13.
In the Servia the machinery consists of three cylinder compound surface condensing engines, one cylinder being 72 inches, and two 100 inches in diameter, with a stroke of piston of 6 feet 6 inches. There are seven boilers and thirty-nine furnaces. Practically the Servia is a five decker, as she is built with four decks—of steel, covered with yellow pine—and a promenade reserved for passengers. There is a music room on the upper deck, which is 50 feet by 22 feet, and which is handsomely fitted up with polished wood panelings. For the convenience of the passengers there are no less than four different entrances from the upper deck to the cabins. The saloon is 74 feet by 49 feet, with sitting accommodations for 350 persons, while the clear height under the beams is 8 feet 6 inches. The sides are all in fancy woods, with beautifully polished inlaid panels, and all the upholstery of the saloon is of morocco leather. For two-thirds of its entire length the lower deck is fitted up with first class staterooms. The ship is divided into nine water-tight bulkheads, and she is built according to the Admiralty requirements for war purposes. There are in all twelve boats equipped as life-boats. The Servia possesses a peculiarity which will add to her safety, namely, a double bottom, or inner skin. Thus, were she to ground on rocks, she would be perfectly safe, so long as the inner skin remained intact. Steam is used for heating the cabins and saloons, and by this means the temperature can be properly adjusted in all weathers. In every part of the vessel the most advanced scientific improvements have been adopted. The Servia leaves Liverpool on October 22.
The Alaska, whose owners, it is understood, are determined to make her beat all afloat in speed, does not sail until November 5, and therefore it is premature to say anything about her interior equipments. She is the sister of the celebrated Arizona, and was built by the well-known firm of Elder & Co., on the Clyde.
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IMPROVED ROAD LOCOMOTIVE.
Several attempts have been made to connect the leading wheels of a traction engine with the driving wheels, so as to make drivers of all of them, and thus increase the tractive power of the engine, and to afford greater facilities for getting along soft ground or out of holes. The wheels with continuous railway and India-rubber tires have been employed to gain the required adhesion, but these wheels have been too costly, and the attempts to couple driving and leading wheels have failed. The arrangement for making the leading wheels into drivers, illustrated on page 4825, has been recently brought out by the Durham and North Yorkshire Steam Cultivation Company, Ripon, the design being by Messrs. Johnson and Phillips. The invention consists in mounting the leading axle in a ball and long socket, the socket being rotated in fixed bearings. The ball having but limited range of motion in the socket, is driven round with it, but is free to move in azimuth for steering.
This engine has now been in use more than twelve months in traction and thrashing work, and, we are informed, with complete success. The illustrations represent a 7-horse power, with a cylinder 8 in. diameter by 12 in. stroke, and steam jacketed. The shafts and axles are of Bowling iron. The boiler contains 140 ft. of heating surface, and is made entirely of Bowling iron, with the longitudinal seams welded. The gearing is fitted with two speeds arranged to travel at 1 and 3 miles per hour, and the front or hind road wheels can be put out of gear when not required. The hind driving wheels are 5 ft. 6 in. diameter, and the front wheels 5 ft.; weight of engine 8 tons.—The Engineer.
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AMERICAN MILLING METHODS.
[Footnote 1: A paper read before the meeting of the Pennsylvania State Millers Association at Pittsburgh, Pa., by Albert Hoppin, Editor of the Northwestern Miller.]
By ALBERT HOPPIN.
To speak of the wonderful strides which the art of milling has taken during the past decade has become exceedingly trite. This progress, patent to the most casual observer, is a marked example of the power inherent in man to overcome natural obstacles. Had the climatic conditions of the Northwest allowed the raising of as good winter wheat as that raised in winter wheat sections generally, I doubt if we should hear so much to-day of new processes and gradual reduction systems. So long as the great bulk of our supply of breadstuffs came from the winter wheat fields, progress was very slow; the mills of 1860, and I may even say of 1870, being but little in advance, so far as processes were concerned, of those built half a century earlier. The reason for this lack of progress may be found in the ease with which winter wheat could be made into good, white, merchantable flour. That this flour was inferior to the flour turned out by winter wheat mills now is proven by the old recipe for telling good flour from that which was bad, viz.: To throw a handful against the side of the barrel, if it stuck there it was good, the color being of a yellowish cast. What good winter wheat patent to-day will do this? Still the old time winter wheat flour was the best there was, and it had no competitor. The settling up of the Northwest which could not produce winter wheat at all, but which did produce a most superior article of hard spring wheat, was a new factor in the milling problem. The first mills built in the spring wheat States tried to make flour on the old system and made a most lamentable failure of it. I can remember when the farmer in Wisconsin, who liked a good loaf of bread, thought it necessary to raise a little patch of winter wheat for his own use. He oftener failed than succeeded, and most frequently gave it up as a bad job. Spring wheat was hard, with a very tender, brittle bran. If ground fine enough to make a good yield a good share of the bran went into the flour, making it dark and specky. If not so finely ground the flour was whiter, but the large percentage of middlings made the yield per bushel ruinously small. These middlings contained the choicest part of the flour producing part of the berry, but owing to the dirt, germ, and other impurities mixed with them, it was impossible to regrind them except for a low grade flour. Merchant milling of spring wheat was impossible wherever the flour came in competition with winter wheat flours. At Minneapolis, where the millers had an almost unlimited water power, and wheat at the lowest price, merchant milling was almost given up as impracticable. It was certainly unprofitable. To the apparently insurmountable obstacles in the way of milling spring wheat successfully, we may ascribe the progress of modern milling. Had it been as easy to raise good winter wheat in Wisconsin and Minnesota as in Pennsylvania and Ohio, or as easy to make white flour from spring as from winter wheat, we should not have heard of purifiers and roller mills for years to come.
The first step in advance was the introduction of a machine to purify middlings. It was found that the flour made from these purified middlings was whiter than the flour from the first grinding and brought a better price than even winter wheat flours. Then the aim was to make as many middlings as possible. To do this and still clean the bran so as to make a reasonable yield the dress of the burrs was more carefully attended to, the old fashioned cracks were left out, the faces and furrows made smooth, true, and uniform, self-adjusting drivers introduced, and the driving gear better fitted. Spring wheat patents rapidly rose to the first place in the market, and winter wheat millers waked up to find their vantage ground occupied by their hitherto contemned rivals. To their credit it may be said that they have not been slow in taking up the gauntlet, and through the competition of the millers of the two climatically divided sections of this country with each other and among themselves the onward march of milling progress has been constantly accelerated. Where it will end no man can tell, and the chief anxiety of every progressive miller, whether he lives in Pennsylvania or Minnesota, is not to be left behind in the race.
The millers of the more Eastern winter wheat States have a two-fold question to solve. First, how to make a flour as good as can be found in the market, and second, how to meet Western competition, which, through cheap raw material and discriminating freight rates, is making serious inroads upon the local markets. Whether the latter trouble can be remedied by legislature, either State or national, or not, remains to be proven by actual trial. That you can solve the first part of the problem satisfactorily to yourselves depends upon your readiness to adopt new ideas and the means you have at hand to carry them out. It is manifestly impossible to make as good a flour out of soft starchy wheat as out of that which is harder and more glutinous. It is equally impossible for the small mill poorly provided with machinery to cope successfully with the large merchant mill fully equipped with every appliance that American ingenuity can suggest and money can buy. I believe, however, that a mill of moderate size can make flour equally as good as the large mill, though, perhaps, not as economically in regard to yield and cost of manufacture.
The different methods of milling at present in use may be generally divided into three distinct processes, which, for want of any better names, I will distinguish as old style, new process, and gradual reduction. Perhaps the German division of low milling, half high milling, and high milling is better. Old style milling was that in general use in this country up to 1870, and which is still followed in the great majority of small custom or grist mills. It is very simple, consisting of grinding the wheat as fine as possible at the first grinding, and separating the meal into flour, superfine or extra, middlings, shorts, and bran. Given a pair of millstones and reel long enough, and the wheat could be made into flour by passing through the two. Because spring wheat was so poorly adapted to this crude process, it had to be improved and elaborated, resulting in the new process.
At first this merely consisted of purifying and regrinding the middlings made in the old way. In its perfected state it may be said to be halfway between the old style and gradual reduction, and is in use now in many mills. In it mill stones are used to make the reductions which are only two in number, in the first of which the aim of the miller is to make as many middlings as he can while cleaning the bran reasonably well, and in the second to make the purified middlings into flour. In the most advanced mills which use the new process, the bran is reground and the tailings from the coarse middlings, containing germ and large middlings with pieces of bran attached, are crushed between two rolls. These can hardly be counted as reductions, as they are simply the finishing touches, put on to aid in working the stuff up clean and to permit of a little higher grinding at first. Regarding both old style and new process milling, you are already posted. Gradual reduction is newer, much more extensive, and merits a much more thorough explanation. Before entering upon this I will call your attention to one or two points which every miller should understand.
The two essential qualities of a good marketable flour are color and strength. It should be sharply granular and not feel flat and soft to the touch. A wheat which has an abundance of starch, but is poor in gluten, cannot make a strong flour. This is the trouble with all soft wheats, both winter and spring. A wheat which is rich in gluten is hard, and in the case of our hard Minnesota wheat has a very tender bran. It is comparatively easy to make a strong flour, but it requires very careful milling to make a flour of good color from it. Probably the wheat which combines the most desirable qualities for flour-making purposes is the red Mediterranean, which has plenty of gluten and a tough bran, though claimed by some to have a little too much coloring matter, while the body of the berry is white. By poor milling a good wheat can be made into flour deficient both in strength and color, and by careful milling a wheat naturally deficient in strength may be made into flour having all the strength there was in the wheat originally and of good color. Good milling is indispensable, no matter what the quality of the wheat may be.
The idea of gradual reduction milling was borrowed by our millers from the Hungarian mills. There is, however, this difference between the Hungarian system and gradual reduction, as applied in this country, that in the former, when fully carried out, the products of the different breaks are kept separate to the end, and a large number of different grades of flour made, while in the system, as applied in this country, the separations are combined at different stages and usually only three different grades of flour made, viz.: patent, baker's, or as it is termed in Minnesota, clear flour, and low grade or red dog. In the largest mills the patent is often subdivided into first and second, and they may make different grades of baker's flour, these mills approaching much nearer to the Hungarian system, though modifying it to American methods and machinery. In mills of from three to five hundred barrels daily capacity, it is hardly possible or profitable to go to this subdivision of grades, owing to the excessive amount of machinery necessary to handling the stuff in its different stages of completion. The Hungarian system has, therefore, been greatly modified by American millers and milling engineers to adapt it to the requirements of mills of average capacity. This modified Hungarian system we call gradual reduction. It can be profitably employed in any mill large enough to run at all on merchant work. So far it has not been found practicable to use it in mills of less than one hundred and twenty-five to one hundred and fifty barrels capacity in twenty-four hours, and it is better to have the mill of at least double this capacity.
Gradual reduction, as its name implies, consists in reducing the wheat to flour, shorts, and bran, by several successive operations or reductions technically called breaks, the process going on gradually, each break leaving the material a little finer than the preceding one. Usually five reductions or breaks are made, though six or seven may be used. The larger the number of breaks the more complicated the system becomes, and it is preferable to keep it as simple as possible, for even at its simplest it requires a good, wide-awake thinking miller to handle it successfully. When it is thoroughly and systematically carried out in the mill it is without question as much in advance of the new process as that is ahead of the old style of milling.
In order that I may convey to you as clear an idea of gradual milling reduction as possible, I will give as fully as possible the programme of a mill of one hundred and fifty barrels maximum daily capacity designed to work on mixed hard and soft spring wheat, and which probably will come much nearer to meeting the conditions under which you have to mill than any other I have found readily obtainable. I have chosen a mill of this size, first, because following out the programme of a larger one would require too much time and too great a repetition of details and not give you any clearer idea of the main principles involved, and secondly, because I thought it would come nearer meeting the average requirements of the members of your association. Your worthy secretary cautioned me that I must remember that I was going to talk to winter wheat millers. The main principles and methods of gradual reduction are the same, whether applied to spring or winter wheat; the details may have to be varied to suit the varying conditions under which different mills are operated. For this programme I am indebted to Mr. James Pye, of Minneapolis, who is rapidly gaining an enviable and well deserved reputation as a milling engineer, and one who has given much study to the practical planning and working of gradual reduction mills.
And right here let me say that no miller should undertake to build a gradual reduction mill, or to change over his mill to the gradual reduction system, until he has consulted with some good milling engineer (the term millwright means very little nowadays), and obtained from him a programme which shall fit the size of the mill, the stock upon which it has to work, and the grade of flour which it is to make. This programme is to the miller what a chart is to the sailor. It shows him the course he must pursue, how the stuff must be handled, and where it must go. Without it he will be "going it blind," or at best only feeling his way in the dark. A gradual reduction mill, to be successful, must have a well-defined system, and to have this system, the miller must have a definite plan to work by. But to go on with my programme.
The wheat is first cleaned as thoroughly as possible to remove all extraneous impurities. In the cleaning operations care should be taken to scratch or abrade the bran as little as possible, for this reason: The outer coating of the bran is hard and more or less friable. Wherever it is scratched a portion is liable to become finely comminuted in the subsequent reductions, so finely that it is impossible to separate it from the flour by bolting, and consequently the grade of the latter is lowered. The ultimate purpose of the miller being to separate the flour portion of the berry from dirt, germ, and bran it is important that he does not at any stage of the process get any dirt or fine bran speck or dust mixed in with his flour, for if he does he cannot get rid of it again. So it must be borne in mind that at all stages of flouring, any abrasion or comminution of the bran is to be avoided as far as possible.
After the wheat is cleaned, it is by the first break or reduction split or cut open, in order to liberate the germ and crease impurities. As whatever of dirt is liberated by this break becomes mixed in with the flour, it is desirable to keep the amount of the latter as small as possible. Indeed, in all the reductions the object is to make as little flour and as many middlings as possible, for the reason that the latter can be purified, while the former cannot, at least by any means at present in use. After the first break the cracked wheat goes to a scalping reel covered with No. 22 wire cloth. The flour, middlings, etc., go through the cloth, and the cracked wheat goes over the tail of the reel to the second machine, which breaks it still finer. After this break the flour and middlings are scalped out on a reel covered with No. 22 wire cloth. The tailings go to the third machine, and are still further reduced, then through a reel covered with No. 24 wire cloth. The tailings go to the fourth machine, which makes them still finer, then through a fourth scalping reel the same as the third. The tailings from this reel are mostly bran with some middlings adhering, and go to the fifth machine, which cleans the bran. From this break the material passes to a reel covered with bolting cloth varying in fineness from No. 10 at the head to No. 00 at the tail. What goes over the tail of this reel is sent to the bran bin, and that which goes through next to the tail of the reel, goes to the shorts bin. The middlings from this reel go to a middlings purifier, which I will call No. 1, or bran middlings purifier. The flour which comes from this reel is sent to the chop reel covered at the head with say No. 9, with about No. 5 in the middle and No 0 at the tail. You will remember that after each reduction the flour and middlings were taken out by the scalping reels. This chop, as it is now called, also goes to the same reel I have just mentioned. The coarse middlings which go over the tail of this reel go to a middlings purifier, which I will designate as No. 2. These go through the No. 0 cloth at the tail of the reel purifier No. 3; those which go through No. 5 cloth got to purifier No. 4; while all that goes through the No. 9 cloth at the head of the reel is dropped to a second reel clothed with Nos. 13 to 15 cloth with two feet of No. 10 at the tail. The flour from this reel goes to the baker's flour packer; that which drops through the No. 10 is sent to the middlings stone, while that which goes over the tail of the reel goes to purifier No. 4. We have now disposed of all the immediate products of the first five breaks, tracing them successively to the bran and shorts bins, to the baker's flour packer and to the middlings purifiers, a very small portion going to the middlings stone without going through the purifiers.
The middlings are handled as follows in the purifiers. From the No. 1 machine, which takes the middlings from the fifth break, the tailings go to the shorts bin, the middlings which are sufficiently well purified go to the middlings stone, while those from near the tail of the machine which contain a little germ and bran specks go to the second germ rolls, these being a pair of smooth rolls which flatten out the germ and crush the middlings, loosening adhering particles from the bran specks. From the second germ rolls the material goes to a reel, where it is separated into flour which goes into the baker's grade, fine middlings which are returned to the second germ rolls at once, some still coarser which go to a pair of finely corrugated iron rolls for red dog, and what goes over the tail of the reel goes to the shorts bin. The No. 2 purifier takes the coarse middlings from the tail of the first or chop reel as already stated. The tailings from this machine go to the shorts bin, some few middlings from next the tail of the machine are returned to the head of the same machine, while the remainder are sent to the first germ rolls. The reason for returning is more to enable the miller to keep a regular feed on the purifiers than otherwise. The No. 3 purifier takes the middlings from the 0 cloth on the chop reel. From purifier No. 3 they drop to purifier No. 5. A small portion that are not sufficiently well purified are returned to the head of No. 3, while those from the head of the machine, which are well purified, are sent to the middlings stones. The remainder, which contain a great deal of the germ, are taken to the first germ rolls, in passing which they are crushed lightly to flatten the germ without making any more flour than necessary. The No. 4 purifier takes the middlings from No. 2 and also from No. 5 cloth on the chop reel and from the No. 10 on the tail of the baker's reel. The middlings from the head of this machine go to the middlings stones, and the remainder to purifier No. 6. The tailings from Nos. 3, 4, 5, and 6 go to the red dog rolls. A small portion not sufficiently well purified are returned from No. 6 to the head of No. 4, while the cleaned middlings go to the middlings stones.
The portions of the material which have not been traced either to the baker's flour or the bran and shorts bins are the middlings which have gone to the middlings stones, the germy middlings which have gone to the first germ rolls, and the tailings from purifiers Nos. 3, 4, 5, and 6, and some little stuff not quite poor enough for shorts from the reel following the second germ rolls. Taking these seriatim: the middlings after passing through the middlings stones, go to the first patent reel covered with eleven feet of No. 13 and four feet of No. 8. The flour from the head of the reel goes to the patent packer, that from the remainder of the reel is dropped to another reel, while the tailings go to the No. 4 purifier. The lower patent reel is clothed with No. 14 and two feet of No. 10 cloth; from the head of the reel the flour goes to the patent packer, the remainder that passes through the No. 10 cloth which will not do to go into the patent, being returned to the middlings stones, while the tailings are sent to the No. 4 purifier.
The germ middlings, after being slightly crushed as before stated, are sent to a reel covered with five feet of No. 13 cloth, five feet of No. 14, and the balance with cloth varying in coarseness from No. 7 to No. 00. The flour from this reel goes into the patent, the tailings to the red dog rolls, the middlings from next the tail of the reel which still contain some germ to the second germ rolls, while the middlings which are free from germ go to the middlings stones.
The tailings from purifiers 3, 4, 5, and 6, the material from the reel following the second germ rolls, which is too good for shorts, but not good enough to be returned into middlings again, and the tailings from the reel following the first germ rolls are sent to the red dog rolls, which, as I have stated, are finely corrugated. Following these rolls is the red dog reel. The flour goes to the red dog bin, the tailings to the shorts bin, while some stuff intermediate between the two, not fine enough for the flour but too good for shorts, is returned to the red dog rolls.
This finishes the programme. I have not given it as one which is exactly suited to winter wheat milling. However, as I said before, the general principles are the same in either winter or wheat gradual reduction mills, and the various systems of gradual reduction, although they differ in many points, and although there are probably no two engineers who would agree as to all the details of a programme, the main ideas are essentially the same. The system has been well described as one of gradual and continued purification. In the programme above given the idea was to fit up a mill which should do a maximum amount of work of good quality with a minimum amount of expenditure and machinery. In a larger mill or even in a mill of the same capacity where money was not an object, the various separations would probably be handled a little differently, the flour and middlings from the first and fifth breaks being handled together, and those from the second, third, and fourth breaks being also handled together. The reason for this separation being that the flour from the first and fifth breaks contain, the first a great deal of crease dirt, and the fifth more bran dust than that from the other breaks, the result being a lower grade of flour. The object all along being to keep the amount of flour with which dirt can get mixed as small as possible, and not to lower the grade of any part of the product by mixing it with that which is inferior, always bearing in mind that the aim is to make as many middlings as possible, for they can be purified while the flour can not, and that whenever any dirt is once eliminated it should be kept out afterwards. This leads me to say that if a miller thinks the adoption of rolls or reduction machines is all there is of the system, he is very much mistaken. If anything, more of the success of the mill depends upon the careful handling of the stuff after the breaks are made, and here the miller who is in earnest to master the gradual reduction system will find his greatest opportunities for study and improvement. A few years back it was an axiom of the trade that the condition of the millstone was the key to successful milling. This was true because the subsequent process of bolting was comparatively simple. Now the mere making of the breaks is a small matter compared with the complex separations which come after. In the foregoing programme we had five breaks or successive reductions. Although this is better than a smaller number, I will here say that it is not absolutely essential, for very good work is done with four breaks. The mill for which this programme was made, including the building, cost about $15,000, and is designed to make about sixty per cent. of patent, thirty-five per cent. of baker's, and five per cent. of low grade, results which are in advance of many larger and more pretentious mills.
One difficulty in the way of adapting the gradual reduction system to mills of very small capacity is that the various machines require to be loaded to a certain degree in order to work at their best. It is only a matter of short time when our milling inventors will design machinery especially for small mills; in fact they are now doing it, and every day brings it more within the power of the small miller to improve his manner of milling. To show what can be done in this direction I will briefly describe a mill of about ninety barrels maximum capacity per twenty-four hours, which is as small as can be profitably worked. I will premise this description by saying it is designed with a view to the greatest economy of cost, the best trade of work, and to reduce the amount of machinery and the handling of the stuff as much as possible. This latter point is of much importance in any mill, either large or small, no matter upon what system it is operated, for it takes power to run elevators and conveyors, and especially in elevating and conveying middlings, especially those made from winter wheat, their quality is inured and a loss incurred, by the unavoidable amount of flour made by the friction of the particles against each other. So much is this the case that in one of our largest mills it is deemed preferable to move the middlings from one end of the mill to the other by means of a hopper bin on a car which runs on a track spiked to the floor, rather than to employ a conveyor. A mill built as I am going to describe would require from fifty to sixty horse-power to run it, and including steam power and building would cost from $10,000 to $12,000, according to location. I give it as of interest to those among your number who own small mills and may contemplate improving them.
The building is four stories high, including basement, and thirty-two feet square. It would be some better to have it larger, but it is made this small to show how small a space a mill of this size can be made to occupy. No story is less than twelve feet high. The machinery Is very conveniently arranged, and there is plenty of room all around. The system is a modification of the gradual reduction system, the middlings being worked upon millstones. The first break is on one pair of 9 x 18 inch corrugated iron rolls, eight corrugations to the inch, the corrugations running parallel with the axis of the rolls. The second break on rolls having twelve corrugations to the inch, the third sixteen, and the fourth twenty to the inch, while the fifth break, where the bran is finally cleaned, has twenty-four corrugations to the inch. The basement contains the line shaft and pulleys for driving rolls, stones, cockle machine, and separator. The only other machinery in the basement is the cockle machine. The line shaft runs directly through the center of the basement, the power being from engine or water wheel outside the building. The first floor has the roller mills in a line nearly over the line shaft below, the middlings stones, two in number, at one side opposite the entrance to the mill, the receiving bin at one side of the entrance in the corner of the mill, and the two flour packers for the baker's and patent flour in the other corner. This arrangement leaves over half of the floor area for receiving and packing purposes. The bolting chests, one with six reel and the other with three reel begin on the second floor and reach up into the attic. An upright shaft from the line shaft in the basement geared to a horizontal shaft running through the attic parallel with the line shaft below, comprise about all the shafting there is in the mill. There is a short shaft on the second floor from which the two purifiers on this floor and the two in the attic are driven, and another short shaft on the first floor to drive the packers. There are four purifiers, two on the second floor, and two more directly over them in the attic. The elevator heads are all directly upon the attic line shaft, and the bolting chests are driven by uprights dropped from this shaft. The combined smutter and brush machine is on the third floor at one end of the bolting chests and directly over the stock hoppers. This comprises all the machinery in the mill. The programme is about as follows:
The break reels are clothed as follows: First break No. 20, wire cloth, second break No. 22, third break No. 24, and fourth break No. 24. The material passing through these scalping reels, now called chop, goes to a series of reels, the first clothed with Nos. 6, 4, and 0. The material passing over the tail is sent to the germ purifier, that passing through Nos. 4 and 0, to the coarse middlings purifier, and that through the No. 6 goes to the reel below clothed with Nos. 12 and 13. Some nice granular flour is taken off from this reel; the remainder, which passes over the tail and through the cutoffs, goes to the next reel below clothed with Nos. 14, 15, and 9. Some good flour comes from the 14 and 15; that which passes through the 9 goes at once to the stones without purifying, while that which passes over the tail is sent to the fine middlings purifiers.
After the purification, the middlings are ground on stones and bolted on Nos. 13 and 14 cloth, after having been scalped on No 8. The germ middlings are crushed on smooth rolls and bolted on Nos. 12 and 13. What is not crushed fine enough goes with poor tailings to the second germ rolls, and from these to a reel by themselves or to the fifth reduction or bran reel. A mill of this kind could be made much more perfect by an expenditure of two or three thousands dollars more. I have instanced it to show what can be done with gradual reduction in a very small way.
In mills of from three hundred to five hundred barrels capacity and still larger, the programme differs considerably from that I have sketched, the middlings being graded and handled with little, if any, returning, and are sized down on the smooth rolls, a much larger percentage of the work of flouring being done on millstones. For a three hundred barrel roller mill, the following plant is requisite: five double corrugated roller mills, five double smooth roller mills, three pairs of four foot burrs sixteen purifiers, four wire scalping reels, six feet long, one reel for the fifth break, one reel for low grade flour, eight chop reels, seven reels for flour from smooth rolls, three reels for the stone flour, two grading reels, three flour packers, and necessary cleaning machinery. The reels are eighteen feet thirty-two inches. The programme is necessarily more complicated.
When it comes to the machinery to be employed in making the reductions or breaks, the miller has several styles from which to choose. Which is best comes under the head of what I don't know, and moreover, of that which I have found no one else who does know. Each machine has its good points, and the mill owner must make his own decision as to which is best suited to his purpose. The main principles involved are to abrade the bran as little as possible while cleaning it thoroughly, and to make as little break flour, and as many middlings as possible, the latter to be made in such shape as to be the most easily purified. Regarding the difference between spring and winter wheat for gradual reduction milling, it may be stated something after this manner: Spring wheat has a thinner and more tender bran, makes more middlings because it is harder, and for the same reason the flour is more inclined to be coarse and granular. In milling with winter wheat, especially the better varieties, there will be more break flour made, the middlings will be finer with fewer bran specks, and the bran more easily cleaned, because it will stand harsher treatment. Winter wheat, moreover, requires more careful handling in making the breaks, not because of the bran, but to avoid breaking down the middlings, and making too much and too fine and soft break flour. In order to keep the flour sharp and granular, coarser cloths are used in bolting, and because the middlings are finer the bolting is not so free and a larger bolting surface is required. In milling either spring or winter wheat there should be ample purifying capacity, it being very unwise to limit the number of machines, so that any of them will be overtaxed. The day has gone by when one purifier will take care of all the middlings in the mill.
There is one point which is of much interest to mill owners who wish to change their mills over to the gradual reduction process, that is, how far they can utilize their present plan of milling machinery in making the change. Of course the cleaning machinery is the same In both cases, so are the elevators, conveyors, bolting chests, etc. But to use the millstone is a debatable question. After carefully considering the matter I have come to the conclusion that it has its place, and an important one at that, under the new regime, viz., that of reducing the finer purified middlings to flour. The reason for this lies in the peculiar construction of the wheat berry. If the interior of the berry were one solid mass of flour, needing only to be broken up to the requisite fineness, it could be done as well on the rolls. But instead of this, as is well known, the flour part of the berry is made up of a large number of granules or cells, the walls of which are cellular tissue, different from the bran in that it is soft and white instead of hard and dark colored. It is also fibrous to a certain extent, and when the fine middlings are passed between the rolls instead of breaking down and becoming finer, it has a tendency to cake up and flatten out, rendering the flour soft and flaky. It does not hurt the color, but it does hurt the strength. When the millstone is used in place of the roll the flour is of equally good color, and more round and granular. I know that in this the advocates of smooth rolls will differ from my conclusions, but I believe that the final outcome will be the use of millstones on the finer middlings, and in fact on all the middlings that are thoroughly freed from the germ.
It has been said that that which a man gives the most freely and receives with the worst grace is advice. I will, however, close with a little of the article which may not be wholly put of place. If you have a mill do not imagine that the addition of a few pairs of rolls, a purifier or two, and a little overhauling of bolting-chests, is going to make it a full-fledged Hungarian roller mill. If you are going to change an old mill or build a new one, do not take the counsel or follow the plans of every itinerant miller or millwright who claims to know all about gradual reduction. No matter what kind of a mill you want to build, go to some milling engineer who has a reputation for good work, tell him how large a mill you want, show him samples of the wheat it must use and the grades of flour it must make, and have him make a programme for the mill and plan the machinery to fit it. Then have the mill built to fit the machinery. When it starts follow the programme, whether it agrees with your preconceived notions or not, and the mill will, in ninety-nine cases out of one hundred, do good work.
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MACHINE FOR DOTTING TULLES AND OTHER LIGHT FABRICS.
Dotted or chenilled tulles are fabrics extensively used in the toilet of ladies, and the ornamentation of which has hitherto been done by the application to the tissue, by hand, either of chenille or of small circles previously cut out of velvet. This work, which naturally takes considerable time, greatly increases the cost price of the article.
A few trials at doing the work mechanically have been made, but without any practical outcome. The workwomen who do the dotting are paid at Lyons at the rate of 80 centimes per 100 dots; so that if we take tulle with dots counter-simpled 0.04 of an inch, which is the smallest quincunx used, and suppose that the tissue is 31 inches wide and that the daily maximum production is one yard, we find that 400 dots at 80 centimes per 100 = 3 francs and 20 centimes (about 63 cents), the cost of dotting per yard. It is true that the workwoman furnishes the velvet herself.
Mr. C. Ricanet, of Lyons, has recently invented a machine with which he effects mechanically the different operations of dotting, not only on tulles but also upon gauzes or any other light tissues whatever, such as those of cotton, silk, wool, etc. Aided by a talented mechanic, Mr. Ricanet has succeeded in constructing one of those masterpieces of wonderfully accurate mechanism of which the textile industry appears to have the monopoly—at least it is permissible to judge so from the remarkable inventions of Vaucanson, Jacquard, Philippe de Girard, Heilmann, and others.
The object of this new machine, then, which has been doing its wonderful work for a few days only, is to reproduce artificially chenille embroidered on light tissues, by mechanically cutting out and gluing small circles of velvet upon these fabrics.
For this purpose all kinds of velvet may be employed, and, in order to facilitate the cutting, they are previously coated on the reverse side with any glue or gum whatever, which gives the velvet a stiffness favorable to the action of the punch. To effect the object desired the apparatus has three successive operations to perform: first, cutting the circles; second, moistening; and third, fastening down the dots upon the tissue according to a definite order and spacing. The machine may be constructed upon any scale whatever, although at present it is only made for operating on pieces 31 inches wide, that being the normal width of dotted tulles. The quincuncial arrangement of the dots is effected by the punching, moistening, and fastening down of odd and even dots, combined with the forward movement of the tissue to be chenilled.
The principal part of the machine is the cam-shaft, A (Figs. 1, 2, and 3), which revolves in the direction of the arrows and passes in the center of 80 cam-wheels, 40 of which are odd and 40 even, alternately opposed to each other. This shaft actuates, through its two extremities, the different combined motions in view of the final object to be attained, and also carries the motive pulleys, PP'. Figs. 1 and 2 show the profile of two of these opposed cam-wheels—the arrangement by means of which two rows of dots (odd and even) are laid down upon the tissue during one revolution of the shaft or drum, A. Each of the wheels carries three cams (Figs. 1 and 3), the first, (a), corresponding to the punching; the second, (a'), to the moistening, and the third, (a''), to the gluing down of the dots.
The annexed figure, one-quarter actual size, shows in section the details of the cutting mechanism. To each cam-wheel there corresponds one punch, and the eighty punches are arranged side by side and parallel upon a shaft, B, a spring, b, holding them constantly against the circumference of the cam-wheels. In Fig. 2 only one of these details is shown. The punching arrangement consists of an ordinary punch, c, of variable diameter, screwed to the extremity of a tube, d, which is itself suspended from the end of the lever, p, but which can receive from it at the desired moment the pressure necessary to effect the cutting. The vertical position of these multiple tubes is insured by a guide, e, which is thoroughly indispensable. Through each of the tubes, d, there passes a plunger designed for expelling from the punch the piece that has been cut out of the velvet, and for gluing it down to the fabric. The two small springs, b' and b'', tend continually to lift the tubes as well as the plunger. The whole mechanism is affixed to solid cast-iron frames, and the machine itself may be mounted on wooden supports or a metal frame.
The punching is effected on a bronze straight-edge, C, which slides in a cast-iron channel, D. This presents alternately, in its movement, entire and punctured spaces, the former for receiving the blow of the punch and the latter for allowing passage at the desired moment to the plunger as it goes to fasten the dots upon the tulle which is passing along underneath the channel, D. The punching is done primarily and principally by pressure, but, in order to facilitate the complete detachment of filaments which might retain the punched-out piece, the punch is likewise given at the same time a slight rotary motion, thus imitating mechanically what is performed by hand in the maneuver of all punches. This rotary motion is communicated to the punches by means of levers actuated by an eccentric, E, and which move the frame, h, whose bars engage with the horizontal lever, g, soldered to the tube, d, thus causing the latter at the very moment the punch descends to revolve from right to left. The forty punches in operation cause the frame to return to its initial position through the action of the springs, b'. We say forty, since the inventor, in principle, has admitted 80 punches, operating 40 as odd and 40 as even; obtaining in this way a dotting in a regular quincunx of one yard, that is to say, 80 dots arranged in two rows on a fabric 31 inches wide. But it is evident that a much larger quincunx may be had by putting in play only a half, a third, or a fourth of the punches, and causing the tulle and velvet to advance proportionally. For this purpose it is only necessary to unscrew the punches which are not to act, and to substitute for the ratchet wheel which controls the unrolling of the I tulle, another having a number of teeth proportioned to the desired spacing of the dots.
The punching having been executed, and the drum, A, continuing to revolve, the punches rise a little owing to the conformation of the cam-wheel, and through the action of the springs, b, and allow the moistener to move forward to dampen the little circles which remain at the orifice of the punches. The moistener or dampener is a sort of pad equal in length to the field of action of the punches, and is affixed to a cross-bar, F, which is connected at its two extremities with the levers, G, that are actuated by the cam-wheels, H. These cam-wheels, or eccentrics, H, which are mounted on the shaft of the drum, A, cause the moistener to move forward as soon as the punches rise after operating, and, when it arrives beneath the punches, the larger cams, a, of the cam-wheels, A, press the latter upon the pad and thus effect the dampening of the circles of velvet.
Immediately afterwards, the same eccentrics, H, acting on a lever, I, uncover the holes in the straight-edge, C, and the channel, D. The large cams, a", of the wheel, A, then acting very powerfully upon the respective punches, cause these latter to pass through the orifices so that the extremity of each punch comes within about one twenty-fifth of an inch of the fabric to be dotted. In this passage of the tube, d, a small rod, i, connected by a lever with the plunger, f, is made to abut against the guide, e, thus causing the descent of the plunger to a sufficient degree to push the velvet "dot" out of the tube and to glue it upon the fabric. The manner in which these operations are performed being now well enough understood, let us for a moment examine the motions of the fabrics to be cut and dotted—the first being velvet or any other material, even metal (goldleaf, for example), and the second, the tulle.
The latter has but one motion, and that is in the direction of its length, while the velvet has, in addition to this same motion, another slight one from right to left in the direction of its width in order to diminish waste as much as possible.
The tulle to be dotted is first wound around a roller, R, from whence it passes over the glass guide-roller, R', and between the channel, D, and the table, T, to the roller, R", which is heated by steam.
The hot air which is radiated dries the dots, and from thence the fabric is taken up by other rollers or by any other method. The steam roller, R", carries at one of its extremities a ratchet wheel whose teeth vary in number according to the greater or less rapidity with which the tulle is unrolled. It is actuated by a lever which receives its motion from the eccentric, K.
In the table, T, there is a rectangular receptacle, t, containing rasped or powdered velvet for the purpose of forming a reverse of the dot. This powder attaches itself to the gum and imitates on the wrong side of the fabric a dot similar to that on the upper or right side. The velvet is wound upon the roller, r, and from thence passes under the guiding roller, r', the punches, and the second roller, r". These two latter rollers are solidly connected by a straight-edge fixed at the extremity of the lever, L, whose other end is in continuous correlation with the eccentric, M, which controls the lateral displacements; while the eccentric, O, actuates, by means of the screw, Q, and the ratchet-wheel, S, the longitudinal advance of the velvet. The eccentric, M, is fixed upon an axle, A', which carries a wheel, U, having teeth inclined with respect to its axis, and which derives its motion from the Archimedean screw, N, fixed at one of the extremities of the cam-shaft, A.
We have stated above that the maximum daily hand production of tulle dotted in quincunxes of 0.04 of an inch is about one yard. At the rate of 30 revolutions per minute, and for the same article as that just mentioned, this dotting machine is capable of producing, theoretically, 360 yards per 10 hours; but practically this production is reduced to about 250 yards, which, however, is sufficiently satisfactory.
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THE REPRODUCTION AND MULTIPLICATION OF NEGATIVES.
By ERNEST EDWARDS, B.A.
A question, relative to the subject of reproducing negatives, which was put at a meeting of one of your New York societies, prompts me to make a few remarks on the subject.
Among the numerous and widely diversified ramifications of our business (the Heliotype Printing Company) we have very often to reproduce and multiply negatives in both a direct and reversed form. Various methods for doing this have been tried, and I may here say that I am quite well aware of all the methods that have hitherto been suggested for the purpose, but that which I am to describe is the one to which preference has been given, and which is that known as the carbon process.
A sheet of carbonized paper or "tissue," having been sensitized by immersion in a bath of bichromate of potash, is dried in the dark and placed away for future use, although it is undesirable that it be kept for more than four or five days. This is placed in a printing frame in contact with the negative and exposed for a few minutes, after which it is immersed in water, squeegeed down upon a glass plate, and developed with warm water in the way so well known to carbon printers. The result is a transparency which, owing to having received a sufficient exposure, should show every detail of the negative. The nature of the tissue employed for such a purpose must be such as to give no strong contrasts, but everything reproduced with soft and fine gradation of tone.
The transparency thus obtained forms the clich by which the negatives are subsequently made; and a negative of any size may be obtained by the camera on wet or dry plates. The transparency must, of course, be pointed to the sky and the light transmitted through it, no other light being allowed to reach the lens except that which passes through the carbon transparency. Care must also be taken that the transparency is uniformly lighted. If it is not possible to obtain a northern light, which is best, a reflector of white paper or card may be used which must be sufficiently large and placed at an angle of about forty-five degrees to the transparency.
If the repeated negative is to be of the same size as the original it may be readily produced by repeating the operation of printing on carbon tissue, using the transparency in place of the negative, or using a dry plate in place of the tissue. But on the whole I have satisfied myself that the best results are to be obtained by the first method. There is a greater softness in the latter method, but a greater character and similarity to the original in the former method. There is no doubt that the use of the carbon transparency removes the hardness and riffidness of the outlines peculiar to the older method of a collodion transparency, while with carbon as the medium it is difficult for any but the most experienced eye to distinguish the copy from the original.—Photo Times.
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A NEW METHOD OF MAKING GELATINE EMULSION.
Since gelatine emulsion first came into use one of the greatest troubles in connection with the manufacture of it has been that of washing. According to the first methods the time taken for this part of the process was, I believe, about twenty-four hours. It was very much reduced and the ease of manufacture greatly facilitated by the methods now most generally used, and which were, I believe, first communicated by Messrs. Wratten and Wainright. I refer to those of precipitating with alcohol and of straining the emulsion, when set, through canvas, so as to divide it very finely. When the latter method is resorted to a comparatively short time is sufficient to wash it. This method, although a great improvement upon the older ones, yet leaves much to be desired, especially for those who are not in the habit of making emulsion regularly, but only an occasional batch. When the weather is at all warm it takes a long time for the emulsion to set, unless ice be used, and when once it is set the washing process is an exceedingly "messy" one unless the water be cooled with ice; and the amount of water taken up during washing is often so great that there is considerable difficulty in getting the emulsion to set on the plates. In fact, even in cold weather, it is not an easy process to conduct in the necessary near approach to total darkness.
Considerable suspicion has of late been thrown upon the thoroughness of the alcohol method, unless the emulsion has, previous to precipitation, been freed of the greater part of the soluble salts by washing; that is to say, it is doubtful whether the whole of the soluble salts can be eliminated by the process, and, therefore, unless in exceptionally hot weather, it would seem best not to trust to it, except as a further security against soluble bromide and nitrate after washing. Besides this, the consumption of alcohol is very large. Almost three times the amount of the emulsion precipitated is required, and this, even when methylated spirit is used, adds considerably to the expense. With a view of doing away with the washing altogether, or, rather, of washing of the silver bromide when not incorporated with the gelatine, several processes have been invented. By these silver bromide is obtained in a very fine state of division, ready to mix with gelatine and water in any proportion.
The best known of them is Captain Abney's very ingenious glycerine method, which seems to have been thoroughly successful in his hands, although it has not been in every one's. The silver bromide obtained by his process is not highly sensitive, and requires boiling with gelatine before it is in a fit state to make a rapid plate.
We have lately had described in these columns a method of obtaining bromide in a highly-sensitive state by means of the use of an acid, whereby, after emulsifying and boiling, the viscosity of the gelatine was destroyed, and the bromide in time deposited itself. During the late hot weather, when washing became almost impossible, I was led to cast about for some method of eliminating the soluble salts less tedious and "sloppy" than that of washing, more certain and less expensive than that of precipitating the whole of gelatine with alcohol, and which would take less time than the method of obtaining the bromide in a pure form.
My first idea was to make up the solutions used in emulsifying in a very concentrated form, and, after emulsifying, boiling, and allowing to cool, to add to the thin emulsion thus obtained gelatine to the amount of twenty grains to the ounce, and to precipitate this with alcohol, the rest of the gelatine required to make up the bulk being afterwards added, and the whole thoroughly incorporated by warming and shaking. I was thus successful in reducing the amount of alcohol required to one-third of what would be necessary if the whole of the emulsion were precipitated; but still I found that, if a reliable emulsion were required, the pellicle as formed had to be washed to free it from the last trace of soluble salts.
It now struck me that it might be possible to precipitate the bromide of silver direct from a very weak solution of gelatine, and obtain it in such a form that it might be filtered, washed, and in every way treated as an ordinary precipitate. I tried the following experiment. I took—
1. Silver nitrate....................... 200 grains Water............................... 1 ounce. 2. Ammonia bromide...................... 120 grains. Water................................ 1 ounce. Gelatine............................. 12 grains.
I emulsified the two together in the usual way, allowed the whole to cool, and then poured the thin emulsion into about ten ounces of alcohol, stirring the while. As I had anticipated, a flocculent precipitate was formed, which settled to the bottom of the vessel in a few minutes. This was, in fact, sensitive bromide of silver mixed with a very small quantity of gelatine (about five per cent.), and could, I found, be treated in the same manner as a bromide precipitate from an aqueous solution; it might be washed, either by decantation or by filtration, easily dried, and doubtless could, when dry, be kept for an indefinite time, and be at any time used by mixing with gelatine and water in any proportion thought fit.
I found that a less amount of gelatine than four grains to the ounce was sufficient to carry the bromide down, while five grains to the ounce carried it down in something which I considered too near an approach to a plastic mass.
It will be noticed that in the experiments which I have described the emulsion had not been boiled, so that the sensitiveness of the bromide was probably not great. As the experiment was done in daylight it was of no practical use for making emulsion; but I have since made several batches in this manner and have found them most satisfactory.
When sensitiveness is sought by boiling I rind it necessary to add a small quantity of gelatine after boiling and before precipitating, as that which has been kept for some time at a high temperature seems to have lost the viscosity necessary to carry down the silver bromide in such a form that it can he easily separated from the alcohol and water.
The practical manner of making an emulsion by this method may be as follows. Make up the following mixtures:
I. Silver nitrate...........................................400 grains. Water..................................................... 3 ounces.
II.
Ammonia bromide..........................................240 grains. Gelatine..................................................24 grains Water..................................................... 3 ounces. Hydrochloric acid enough to slightly acidify the solution.
III. Gelatine................................................. 20 grains. Water.................................................... ounce. IV.
Hard gelatine (say Nelson's X opaque, or Mr. A. L. Henderson's)................................240 grains. Soft gelatine (Nelson's No.1)........................... 240 grains. Water.....................................................24 ounces.
Nos. II., III., and IV. are allowed to stand until the gelatine is softened. No. I is then warmed in a hock bottle until the gelatine is just melted, when No. II. is poured into it, a little at a time, with vigorous shaking, until the whole is emulsified. It is then transferred to an ordinary jelly can, which is placed in a saucepan half full of water over a ring Bunsen burner in the dark room, and boiled for half an hour. It is then allowed to cool to about 100 Fahr., when No. III. is added. The whole is then allowed to get quite cool, when it is poured, with stirring, into about one pint of methylated spirit. If it be wished the precipitate may now be filtered out and washed at once like an ordinary filtrate, but I prefer to allow it to settle, which it will do in about five minutes. The supernatant fluid is then gently poured off.
This fluid will have the appearance of still containing a considerable amount of the silver bromide; but if it be kept and filtered it will be seen that the quantity is really so small that it may be disregarded. We all know what an alarming quantity of silver seems to be going down the sink when we wash vessels to which a very small quantity of emulsion is adhering. If filtering be resorted to the liquid which comes through will be quite clear. This was somewhat unexpected by me, as, if an emulsion containing the whole of the gelatine be precipitated into alcohol in the usual way, the alcohol becomes milky with a substance which could not, I imagine, be filtered from it.
Two or three ounces of methylated spirit are now added to the vessel containing the silver bromide, and the latter well mixed with it. This makes the precipitate "firmer"—if such an expression be allowable—and this time it will sink to the bottom almost immediately after the stirring has ceased, and the alcohol may be poured off.
I consider that the bromide in this state is practically free from soluble salts, but it may be washed with one or two changes of water if desired.
No. IV. is now gently heated till the gelatine is melted and the precipitate mixed with it. It must be kept warm for some time, and shaken vigorously until all granularity has disappeared, This is, of course, ascertained by placing a drop of the emulsion on a piece of glass, and examining it. If it be wished to keep the bromide of silver for future use it may be placed on a piece of muslin stretched in the drying-box, when it will dry in a very short time; and, although I cannot speak from experience on this point, it will, I have no doubt, keep for an indefinite time so long as light is kept from it.
If it be desired the ammonio-nitrate method may be used instead of the boiling one, although in my hands it does not give such sensitiveness. If it be desired to use this method, solution Nos. I, II., and IV. are made up exactly as for the boiling method, except that No. II. is not acidified. Liquid ammonia is then poured with stirring into the silver solution, until it blackens and again clears. Emulsification is performed exactly as described above, but instead of boiling, the emulsion is kept at a temperature of about 100 Fahr. for half an hour, when it is poured into the alcohol, no addition of gelatine being previously made.
I think I may claim for the method which I have just described that it is less troublesome and more certain than either the ordinary washing method or the usual one of precipitating with alcohol, while it affords an easy method of making sensitive silver bromide in such a form that it can be more easily stored and afterwards manipulated than if it were in the form of pellicle. The whole of the soluble salts are eliminated, and also any gelatine which may have been destroyed in the cooking. The amount of alcohol used is comparatively small; in fact, to prepare silver bromide for a pint of emulsion very little more than a pint of methylated spirit is required. Besides this I do not think that I would be wrong in saying that the chance of green fog is reduced to a minimum.
Let me take this opportunity of thanking Captain Abney for his prompt reply to my question about the connection between the proportion of bromide to gelatine in emulsions, and the density of resulting images.—W. K. Burton, in British Journal of Photography.
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THE POTTERY AND PORCELAIN INDUSTRIES OF JAPAN.
Japanese chronicles claim that the first pottery was made in the year 660 B.C.; it was not, however, until the Christian era that the art made any considerable advances. In the year 1223 A.D., great improvements were made in manufacture and decoration of the ware. From that date to the sixteenth century the great potteries of Owari, Hizen, Mino, Kioto, Kaga, and Satsuma were established. The Rahn-Yaki, or crackled ware, was first made at Kioto, at the commencement of the sixteenth century. The best old Hizen ware, that which is still the most admired, was made at Arita Hizen, in 1580 to 1585; the old Satsuma dates from 1592. Consul-General Van Buren states that porcelain clays are found in nearly all parts of the country, and the different kinds are usually found in close proximity, and close to canals and rivers, which is of considerable advantage, as affording a means of transport. In all cases every variety of clay used in the manufacture of pottery is found in a natural state; there is no necessity to manufacture the quartzose or fusible clays as is done in other parts of the world, and which adds considerably to the cost of the ware. One of the peculiarities in the clay found in Japan is that it contains both the fusible and infusible materials in such proportions as to make a light, beautiful, translucent, and durable porcelain. At Arita, in Hizen, there is a clay found which contains 783/4 per cent, of silica, and l73/4 per cent, of alumina; from this clay is made the delicate, translucent eggshell ware, without the addition of any other matter. From an adjoining bluff a clay is taken which has 50 per cent, of silica, and 38 per cent, of alumina; from this the common porcelain is made.
Potter's clay is found in very large quantities in the provinces of Yamashiro, Hoki, Turoo Iyo, Hizen, Higo, Owari, Mikaera, Idyn, Musashi, and Mino. In the whole of Japan there are 283 localities where the clay is deposited; many of these only furnish inferior clays, but they are all fitted for use in some of the various kinds of pottery. These clays are thoroughly powdered by means of what is called "balance pounders," worked in some localities by water-power, but the work is often done by hand. The powder is then dried, and stored on boards or in flat boxes. This dough does not go through the process of fermentation. The shaping is almost exclusively done on the potter's wheel, which is set on a pivot working in a porcelain eye. As a rule, the wheel is turned by the potter himself, but in Hizen it is kept in motion by means of a band connected with its pivot and another wheel turned by a boy. In making dishes of other shape than round, a crude mould is sometimes used. After the clay has been shaped on the wheel, it is set away for drying, and usually in two or three days it is considered sufficiently dry for smoothing, which is done on the wheel with a sharp curved knife. The material is now made into "bisque," or biscuit, by a preliminary baking in small ovens, when it is ready for painting, if it is to be painted on the biscuit; if not, it is ready for the glazing. In either event it will then go to the large furnace for the final baking. The kilns for this purpose are always built on hill sides, and are joined together, increasing in size from the lower to the higher ones, and in number from four to twenty five; these kilns are so constructed that the draught is from the lowest one, in addition to which each kiln has its own firing place. The result of this construction is that the upper ones are by far the most heated, and the ware is arranged accordingly; that which requires the least baking, in the lower kiln, and that which requires the greatest heat, in the upper. These connecting kilns have the merit of being heat saving, but they are usually small and badly constructed, and the heat in none of them is uniform.
The glaze is made from the silicious clay and potash extracted from wood ashes. This potash is not a pure white, and this accounts for the dirty color usually to be observed in unpainted Japanese ware. In different districts the painting varies. For instance, in Owari, the greater part of the ware is painted a cobalt blue—the cobalt ore being found in the bluffs near the clay deposits, and is used for painting the cheaper wares, and for this purpose German cobalt is also employed. The painting with cobalt is generally done on the biscuit before glazing. In several districts a very handsome ware is made, and painted on the glaze. For this kind of painting the colors are mixed with a silicate of lead and potash, and baked the third time in a small furnace at a low temperature. The coloring oxides in use are those of copper, cobalt, iron, antimony, manganese, and gold. Japanese porcelain painting may be divided into two categories, decorative and graphic; the first is used to improve the vessel upon which it is placed, and this class includes all the ware except that of the province of Kaga, which would come under the head of graphic, as it delineates all the trades, occupations, sports, customs, and costumes of the people, as well as the scenery, flora, and fauna of the country. "Owari ware" is made in the province of that name; it is not as translucent, but stronger and more tenacious than some of the Hizen manufacture.
The principal potteries are at a village called Sto, twelve miles from the sea; in this village there are more than 200 kilns. The ware is mostly painted a cobalt blue, and is merely of a decorative kind, consisting of branches of trees, grass, flowers, birds, and insects, all these being copied by the artist from nature. All the Owari ware is true hard porcelain, and is strong and durable. In Hizen, a number of wares are manufactured, the best known kind being the "Eurari," which is made at Arita, but painted at Eurari. The colors in use are red, blue, green, and gold; these are combined in various proportions, but, as a rule, the red predominates. Generally the surface of the vessel is divided into medallions of figures, which alternately have red, blue, or white back-ground, with figures in green or blue and gold.
The egg-shell porcelain sold at Nagasaki is made in this province from Arita clay, and this is made from clay with no admixture of fusible matter except that contained by the clay naturally. The province of Satsuma is noted for crackled ware. It is only within a very few years that large vases have been manufactured, and in earlier days the old ware was confined to small vessels. The glaze is a silicate of alumina and potash, and the best ware has a complete network of the finest crackles; the painting is of birds and flowers, and noted for its delicate lines of green, red, and gold.
In Kioto, the ware manufactured is very similar to that produced in Satsuma, but it is lighter and more porous; the decorations are also nearly the same, being of birds and flowers. There is a description of ware made in Kioto, called "Eraku," the whole body of which is covered with a red oxide of iron, and over this mythical figures of gold are traced. That produced in Kagja is faence, and in the style of painting is unlike any other in Japan, the predominating color being a light red, used with green and gold. The designs with which it is profusely decorated are trees, grasses, flowers, birds, and figures of all classes of people, with their costumes, occupations, and pastimes. The "Banko" ware is made at the head of the Owari Bay; it is an unglazed stone-ware, very light and durable, made on moulds in irregular shapes, and decorated with figures in relief. On the island of Awadji, a delicate, creamy, crackled, soft paste porcelain is made. The figures used in decoration are birds and flowers, but outlined by heavy, dark lines.
Consul Van Buren is of opinion that, at no distant day, Japan will be one of the foremost competitors in the pottery markets of the world, on account of the great variety and excellence of the clays, their proximity to the sea, the cheapness of labor, and the beauty and originality of the decorations. Already this important industry has been greatly stimulated by the foreign demand, and by the success of Japanese exhibitors at the Exhibitions of Vienna, Philadelphia, and Paris.—Journal of the Society of Arts.
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Professor Julius E. Hilgard, for twenty years assistant in charge of the office, has been placed in temporary charge of the Coast and Geodetic Survey. It is understood that he will be appointed superintendent to succeed the late Captain Carlile P. Patterson.
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THE FRENCH CRYSTAL PALACE.
The first idea of the French Crystal Palace was suggested by the English structure of the same name at Sydenham, about eight miles from London. Such a structure, as may be readily conceived, requires a site of vast extent, and one that shall be easy of access and possess the most agreeable surroundings. To the promoter of the project, those portions of the park of St. Cloud in the vicinage of the old chateau appeared to combine within themselves all the conditions that were desirable, and he, therefore, on the 15th of December, 1879, addressed the Ministers of Public Works and of Finances asking for the necessary concessions. The extensive specifications have been finally completed and will probably be shortly submitted for the approval of the parliament. The moment has arrived then for the public press to take cognizance of a project which concerns so great interests.
At present we shall say a few words propos of the engraving we present herewith. The French Crystal Palace will consist of one great nave, two lateral naves, two surrounding galleries, and a vast rotunda behind. The principal entrance, located at the head of the avenue leading from the present ruins (which will, ere long, be transformed into a most interesting museum), will exhibit a very striking aspect with its monumental fountain and the dome which it is proposed to erect over the very entrance itself. The whole structure will cover about nineteen acres of ground, thus being two and a half times the extent of the Palace of Industry in the Champs Elysees. The great nave of honor will be nearly 1,650 ft. in length, 78 ft. in width, and 98 ft. in height. The dome will measure exactly 328 ft. in height, or 105 ft. more than the towers of Notre Dame. The structure, with the exception of basement and foundation, will be of glass and iron.
The project which we publish to-day has been studied and gotten up, according to the general plans and dimensions suggested by the promoter, by Mr. Dumoulin, the architect. We are informed that the builder is to be Mr. Alfred Hunnebelle, a contractor well known from the extensive works that he has executed, and who is president of the Syndical Chamber of Contractors of Paris.
Among the annexes of this palace we may note a "Palace of the Republic," to be built on the ruins and designed for illustrious or distinguished visitors, such as the President of the Republic, the Ministers, the Municipal Council of Paris, foreign delegates, etc.; a farm house for special exhibitions and a field for experiments; galleries, cottages, etc.
As for the programme, which embraces six divisions and numerous subdivisions, we are unable to give it at present for want of space; we need only say that it satisfies perfectly all the conditions of so vast an undertaking.
In the hands of the projector, Mr. Nicole, who is well known from his long experience in such matters, the exhibition will undoubtedly prove a success and be instrumental in adding prosperity to all French industries.
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THE GREAT HEAT OF THE SUN.—Prof. S. P. Langley has made the following calculation: A sunbeam one centimeter in section is found in the clear sky of the Alleghany Mountains to bring to the earth in one minute enough heat to warm one gramme of water by 1 C. It would, therefore, if concentrated upon a film of water 1/500th of a millimeter thick, 1 millimeter wide, and 10 millimeters long, raise it 83 1/3 in one second, provided all the heat could be maintained. And since the specific heat of platinum is only 0.0032 a strip of platinum of the same dimensions would, on a similar supposition, be warmed in one second to 2,603 C.—a temperature sufficient to melt it!
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CHATEAU IN THE AEGEAN SEA.
From the site of this building, magnificent views are obtained over the island-dotted sea and the mainland of Asia Minor: but, "though every prospect pleases," it is a land of earthquakes, and unfortunately, the works at the chateau have been suspended, owing to the dreadful calamity which has recently fallen upon the district. The building is intended for the residence of an English lady of exalted rank. It is to be built of local white stone, the hall, staircase, etc., being lined and paved with marbles. The hall is a large apartment about 25 ft. high, with paneled ceiling, having galleries on two sides, giving access to the rooms surrounding it on first floor, and to the turret staircase leading to roofs, etc. With the exception of sanitary apparatus, painted windows, etc. (which will be supplied by English firms), the whole of the work will be executed by native labor. The architect is Mr. Edwin T. Hall, London.—Building News.
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ELECTRIC POWER.
Just now nothing save electricity is talked about in scientific circles. During the meeting of the British Association the greatest possible prominence was given to electrical questions and propositions The success of the electric light, the introduction of the Faure battery with a great flourish of trumpets, and the magnificent display of electrical instruments and machinery at Paris, have all operated to the same end. The daily press has taken the subject up, and journals which were nothing hitherto if not political, now indulge in magnificent rhapsodies concerning the future of electricity. Even eminent engineers, carried away by the intoxication of the moment, have not hesitated to say that the steam engine is doomed, and that its place will be taken by the electricity engine. In the midst of all this noise and clamor and blowing of personal trumpets, it is not easy to keep one's head clear, and mistakes may be made which will cause disappointment to many and retard the progress of electrical science. We confidently expect that electricity will prove a potent agent by and by in the hands of the speculator for extracting gold from the pockets of the public, and we write now to warn our readers in time, and to endeavor to clear the air of some of the mists with which it is obscured. There is, no doubt, a great future before electricity; but it is equally certain that electricity can never do many things which the half informed may be readily made to believe it will do. We propose here to say enough on this point to enlighten our readers, without troubling them with perplexing problems and speculations.
No one at this moment knows what electricity is; but for our present purpose we may regard it as a fluid, non-elastic, and without weight, and universally diffused through the universe. To judge by recently published statements, a large section of the reading public are taught that this fluid is a source of power, and that it may be made to do the work of coal. This is a delusion. So long as electricity remains in what we may call a normal state of repose, it is inert. Before we can get any work out of electricity a somewhat greater amount of work must be done upon it. If this fundamental and most important truth be kept in view it will not be easy to make a grave mistake in estimating the value of any of the numerous schemes for making electricity do work which will ere long be brought before the public. To render our meaning clearer, we may explain that in producing the electric light, for instance, a certain quantity of electricity passes in through one wire to the lamp, and precisely the same quantity passes out through the other wire, and on to the earth or return wire completing the circuit. Not only is the quantity the same, the velocity is also unchanged. But in going through the lamp the current has done something. It has overcome the resistance of the carbons, heated them to a dazzling white heat, and so performed work. In doing this the current of electricity has lost something. Led from the first lamp to a second, it is found powerless—if the first lamp be of sufficient size. What is it that the electricity has lost? It has parted with what electricians would term "potential," or the capacity for performing work. What this is precisely, or in what way the presence or absence of potential modifies the nature of the electric current, no one knows; but it is known that this potential can only be conferred on electricity by doing work on the electricity in the first instance. The analogy between electricity and a liquid like water will now be recognized. So long as the water is at rest, it is inert. If we pump it up to a height, we confer on it the equivalent of potential. We can let the water fall into the buckets of an overshot wheel. Its velocity leaving the tail race may be identical with that at which it left the supply trough to descend on the wheel. Its quantity will be the same. It will be in all respects unchanged, just as the current of electricity passing through a lamp is unchanged; but it has, nevertheless, lost something. It has parted with its potential—capacity for doing work—and it becomes once more inert. But the duty which it discharged in turning the mill wheel was somewhat less than the precise equivalent of the work done in pumping it up to a level with the top of the wheel. In the same way the electric current never can do work equal in amount to the work done on it in endowing it with potential. |
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