An American wood powder, known as Bracket's Sporting Powder, consists of soluble and insoluble nitro-lignine, mixed with charred lignine, humus, and nitrate of soda. Mr F.H. Snyder, of New York, is the inventor of a shell powder known as the "Snyder Explosive," consisting of 94 per cent. nitro-glycerine, 6 per cent. of soluble nitro-cotton, and camphor, which is said to be safe in use. Experiments were made with it in a 6-inch rifled gun, fired at a target 220 yards away, composed of twelve 1-inch steel plates welded together, and backed with 12-inch and 14-inch oak beams, and weighing 20 tons. The shots entirely destroyed it. The charge of explosive used was 10 lbs. in each shell.
~Comparative Tests of Black and Nitro Powders, from "American Field."~— The results given in table below were obtained at the German Shooting Association's grounds at Coepenick, Berlin. Penetration was calculated by placing frames, each holding five cards of 1 millimetre in thickness (equals .03937 inch), and 3 inches apart, in a bee-line, at distances of 20 inches. Velocity, pattern, and penetration were taken at 40 yards from the muzzle of a 12-gauge choke-bore double-barrel gun. Gas pressure was taken by a special apparatus. All shells were loaded with 1-1/8 oz. of No. 3 shot, equal to 120 pellets, and the number given below represents the average number in the 30-inch pattern. The number of sheets passed through gives the average penetration. One atmosphere equals pressure equal to 1 kilogramme (2.2 lbs.) on the square centimetre, hence 1,000 atmospheres equal 2,200 lbs. on the square centimetre. The E.C., Schultze, and Walsrode powders were loaded in Elcy's special shells, 2-1/2 inches long. The averages were taken from a large number of shots, and the same series of shots fired under precisely the same conditions.
_______________________________________________________________________ | | | | | | | | Gas | | | | | | Pressure. | Velocity. | Pattern. | Penetration. | |__________________|____________|___________|____________|______________| | | | | | | | |Atmospheres.| Metres. | | Sheets. | | | | | | | |Fine-grained black| | | | | |powder, standard | | | | | |charge | 514.2 | 280 | 78.6 = 66% | 19.O | | | | | | | |Coarse-grained | | | | | |black powder, | | | | | |standard charge | 473.4 | 281.4 | 78.2 = 65% | 19.4 | | | | | | | |Schultze powder, | | | | | |42 grains | 921.0 | 290.0 | 64.2 = 54% | 20.2 | | | | | | | |Schultze powder, | | | | | |45 grains | 1052.8 | 305.8 | 52.2 = 42% | 20.6 | | | | | | | |E.G. smokeless, | | | | | |42 grains | 920.2 | 298.4 | 81.4 = 67% | 18.8 | | | | | | | |Walsrode, | | | | | |29 grains | 586.4 | 280.6 | 83.0 = 69% | 19.0 | |__________________|____________|___________|____________|______________|
Barometer, 760 mm. Thermometer, 30° C. Hydrometer = 65. Wind, S.W.
~Picric Powders.~—The chief of these is Melinite, the composition of which is not known with certainty. It is believed to be melted picric acid together with gun-cotton dissolved in acetone or ether-alcohol. Walke gives the following proportions—30 parts of tri-nitro-cellulose dissolved in 45 parts of ether-alcohol (2 to 1), and 70 parts of fused and pulverised picric acid. The ether-alcohol mixture is allowed to evaporate spontaneously, and the resulting cake granulated. The French claim, however, that the original invention has been so modified and perfected that the melinite of to-day cannot be recognised in the earlier product. Melinite has a yellow colour, is almost without crystalline appearance, and when ignited by a flame or heated wire, it burns with a reddish-yellow flame, giving off copious volumes of black smoke. Melinite as at present used is said to be a perfectly safe explosive, both as regards manufacture, handling, and storage.
Lyddite,[A] the picric acid explosive used in the British service, is supposed to be identical with the original melinite, but its composition has not been made public.
[Footnote A: Schimose, the Japanese powder, is stated to be identical with
Lyddite and Melinite (Chem. Centr., 1906, 1, 1196).]
Picrates are more often used than picric acid itself in powders. One of the best known is Brugère's Powder, which is a mixture of 54 parts of picrate of ammonia and 45 parts of saltpetre. It is stable and safe to manufacture. It has been used in the Chassepôt rifle with good results, gives little smoke, and a small residue only of carbonate of potash.
The next in importance is Designolle's Powder, made at Bouchon, consisting of picrate of potash, saltpetre, and charcoal. It was made in three varieties, viz., for rifles, big guns, and torpedoes and shells. These powders are made much in the same way as gunpowder. The advantages claimed for them over gunpowder are, greater strength, comparative absence of smoke, and freedom from injurious action on the bores of guns.
Emmensite is the invention of Dr Stephen Emmens, of the United States. The Emmens "crystals" are produced by treating picric acid with fuming nitric acid of specific gravity of 1.52. The acid dissolves with the evolution of red fumes. The liquid, when cooled, deposits crystals, stated to be different to picric acid, and lustrous flakes. These flakes, when heated in water, separate into two new bodies. One of these enters into solution and forms crystals unlike the first, while the other body remains undissolved. The acid crystals are used mixed with a nitrate.