From the statements recently made in the House of Commons during the debate on the navy estimates, when the Parliamentary Secretary stated that the Nile and Trafalgar would probably be the last heavily armored ships of their class, it would appear that the long contest between guns and armor has resulted in a victory for the aggressive force. To what extent this is due to the weapons themselves, and how far to the powder and projectiles used, it would be hard to determine, but certainly the explosive deserves a large share of the glory of the victory. The advances made within the last two or three years in the manufacture of gunpowder for heavy ordnance have been very great, and these advances have been due in a great measure to the development of more perfect mechanical devices for the necessary processes. The hydraulic plant for makingpe prisms necessitates a considerable outlay, which private manufacturers in England were reluctant to incur, until the form of powder likely to be required was definitely settled by the Government authorities. In the mean time the' resources of the Royal Gunpowder Factory at Waltham Abbey were insufficient to meet the demands of the War Department for prismatic “ cocoa “ powder, and private manufacturers in England not having the necessary appliances for its manufacture, large contracts were entered into with German manufacturers. In the mean time, one of our leading firms engaged in gunpowder manufacture had been experimenting with a new form ()f prismatic powder, and having brought their researches to a. satisfactory conclusion, decided to erect a thoroughly efficient plant of the most approved description, in order to manufacture what,is now officially, known as “ Brown X prismatic gunpowder." The result is the hydraulic press which we illustrate, and which Messrs Taylor&Chal-len have recently completed, to the order of Messrs. Curtis&Harvey. This eminen t firm of gunpowder manufacturers have works at Hounslow, Bedfont, and Tunbridge! and also in Scotland. and in South Wales. It was at the Tun-bridge works that the new plant was erected, and it was there that we had an opportunity lately of seeing it iri operation. The accumulator is weighted with cast iron segments, which may readily be put on or removed should the pressure require to be varied. When fully weighted, the pressure is 1,050 lb. per square inch. Three men are required to work each machine, one to manipulate the valves and two to attend to the charger and remove the prisms of powder as they are produced. The operations are as follows : The various conical hoppers, A” which are contained in the carriage of the charger shown on the left of the engraving, are filled with loose grain powder. The charger is then run forward into the press and locked there. By the movement of two levers, which are shown in position in our engraving, the powder is made to fall from the hoppers into the charging tubes, B, 64 in number. These are Bet to hold the required quantity of powder, and great care has to be taken to fill them completely, as exact uniformity is one of the most necessary conditions of getting a powder that will pass the very severe tests now demanded by the government' authorities. By the movement of a lever the charging tubes are carried over 64 corresponding phosphor-bronze bushes in the bush block, C. The charges of powder then fall i n to t h e s e bushes, and the charger is with-d r awn from the press. • The operator at the valves then PRESS FOR THE MANUFACTURE ' OF PRISMATIC GUNPOWDER. © 1886 SCIENTIFIC AMERICAN, INC 94899999999 June 26, 1886. 407 allows water at pressure to flow in above the top ram, which forces down the plunger block. Attached to this are 64 phosphor-bronze hexagonal plungers; these enter the bushes, which they fit with great accuracy. At the same time that the top ram is brought down the bottom ram are caused to ascend. To the latter is attached the plunger block, E, to which are attached 64 hexagonal plungers, that also correspond to and accurately fit the bushes in the bush block. In this way the charges of powder contained” in the bushes are pressed between the plungers. Under ordinary conditions of atmosphere, the pressure is kept on for about ten to twenty seconds, the time varying with the different descriptions of powder. The top plungers are then lifted, and the lower plungers are raised to eject the prisms from the bushes. The prisms are pushed off, clear of the press, on to a woode»-4ray, to be .. removed by ' an attendant. The bottom ram is lowered again into its'"n first position, and the charger is run into the press again ready for the next operation. In this way each machine will make ' 64 pUfems every . two minutes. It • i s necessary, however, that each prism should have a hole through its center in a line with its axis. These holes are formed in the following manner : The bottom plungers have holes bored through, which are of the same diameter as the holes required in the prisms. This allows a number of phosphor-bronze rods, one to each prism, to pass through the plungers and then through the powder in each bush. .These rods stand nearly level with the top of the bush block, and are firmly held by the plate, H, so that the prisms are pressed with these rods in the middle. When the prisms are ejected from the bushes, they are stripped from the rods. It is indispensable that all the prisms produced should be of exactly one size, and should contain precisely similar quantities of powder. Their uniformity is tested by means of immersing them in a bath of mercury, the' readings being taken off on a very accurately marked scale. In working the machines, a -separate valve is used for each operation, and an ingenious automatic arrangement has been devised to prevent the attendant turning a wrong valve, so as to bring down the top ram when the charger is in the machine. There is also a safety liangement to ' prevent damage to the machine should a pipe burst. We have referred to the necessity that exists for producing a II the prisms of a definite and uniform size and specific gravity, in other words, that there should be exactly the same amount of gunpowder, compressed to the same degree, in each specimen. It is this point that has - principally engrossed the attention 0 f the makers of the apparatus, and the result is a beautifully accu rate piece of mechanism. It has only been by the greatest care in finishing to gauge adjustment of parts that the success- undoubtedly achieved by this machinery has been attained. The tests of powder, such as- this, now required by the. War Office are of the most severe description, as- may be gathered from the following details, which represent some of the principal points in the official specification of tests. Size of Pmms.—The prisms to be of the following dimensions : height, 34*8 ± 0'2 millimeter ; diameter (over sides) 34'7 millimeters ± 0*2 millimeter. The hole to be 10 millimeters in diameter. The prisms to be gauged as follows: 219 prisms should fit easily in a metal frame-705 millimeters long, 352 millimeters wide, and 25'3 millimeters high, and should offer no resistance to a straight edge drawn over the top of the frame. Density.—The absolute density of the finished powder must not be less than 1*80. Moisture.— The finished powdet: must not contain more than 2'2 per cent nor less than 1*7 per cent. Velocity.—K charge of 295 lb. of powder in the 12 in. beeech-loading gun (of a gravimetric density of shall give a mean muzzle velocity for the five rounds of not less than 1,900 ft. per second nor more than 1,940 ft. per second, to a proof cylinder having a 'total weight of 714 lb. The mean of the deviations of the muzzle velocities of the several rounds, from the mean velocity of the five rounds, shall not exceed 10 ft.Pressure.—The mean pressure indicated on firing, as above, by the compression of copper cylinders, adjusted in crusher gauges, is not to be greater in any one round than 16 £ tons on the square inch, and the mean of all the pressures shall not exceed 16 tons. These very stringent tests are perhaps the best com ment we could have on the great strides - the' art of making explosives has made within the last few years. It is not so very long since—well, within the memory- of living powder makers—that gunpowder was gunpowder, without any very striking difference for whatever purpose it might be required.' The “ velocity” tests show a wonderful departure from those simple times ; and although the restrictions laid down in this respect may seem unnecessarily severe, and even arbitrary at first glance, on further inquiry we believe there will be found to be sound reason at the bottom of them, and it is only by their strict observance that the accurate practice necessary in modern warfare can be insured. We are glad to learn, therefore, that Messrs. Curtis&Harvey, as English makers, have in the a powder that has passed the government examination, and fulfilled thetests enumerated to the fullest extent, and that British guns can in future be fired with British powder.-Engineering. REFERRING- to baseball, which seems to rage like an epidemic this season, has induced the ./luggestion that the average man in a large city ,must have an easy time, plenty of means, and limited hours of employment, when S,OOO can devote three ,afternoons each week to watching eighteen full-grown 'men toss a baU around a field.
This article was originally published with the title "Prismatic Gunpowder"