The internal pressure not to exceed 3.5 tons.
This Company also manufactures a new form of powder, known as Imperial Schultze. It is a powder somewhat lighter in gravity; 33 grains occupies the bulk charge, as compared with the 42 grains of the old. It follows in its composition much the lines of the older powder, but it is quite free from smoke, and leaves no residue whatever.
~The E.G. Powder.~—This is one of the oldest of the nitro powders. It was invented by Reid and Johnson in 1882. It is now manufactured by the E.G. Powder Company Limited, at their factory near Dartford, Kent, and in America by the Anglo-American E.G. Powder Company, at New Jersey. The basis of this powder is a fine form of cellulose, derived from cotton, carefully purified, and freed from all foreign substances, and carefully nitrated. Its manufacture is somewhat as follows:—Pure nitro-cotton, in the form of a fine powder, is rotated in a drum, sprinkled with water, and the drum rotated until the nitro-cotton has taken the form of grains. The grains are then dried and moistened with ether-alcohol, whereby the moisture is gelatinised, and afterwards coloured with aurine, which gives them an orange colour. They are then dried and put through a sieve, in order to separate the grains which may have stuck together during the gelatinising process.
Since its introduction soon after 1881, E.G. powder has undergone considerable modifications, and is now a distinctly different product from a practical point of view. It is now and has been since 1897 what is known as a 33-grain powder, that is to say, the old standard charge of 3 drams by measure for a 12-bore gun weighs 33 grains, as compared with 42 grains for the original E.G. and other nitro powders. This improvement was effected by a reduction of the barium nitrate and the use of nitro- cellulose of a higher degree of nitration, and also more gelatinisation in manufacture. The granules are very hard, and resist moisture to an extent hitherto unattainable by any "bulk" powder.
Irregularities of pressure in loading have also a minimum effect by reason of the hardness of the grains. The colouring matter used is aurine, and the small quantity of nitrate used is the barium salt. The powder is standardised for pressure velocity with Boulengé chronograph,[A] pattern and gravimetric density by elaborate daily tests, and is continually subjected to severe trials for stability under various conditions of storage, the result being that it may be kept for what in practice amount to indefinite periods of time, either in cartridges or in bulk without any alteration being feared. The E.C. powders are used in sporting guns. No. 1 and No. 2 E.C. are not at present manufactured, E.C. No. 3 having taken their place entirely. Since 1890 these powders have been manufactured under the Borland-Johnson patents, these improved powders being for some time known as the J.B. powders. The E.C. No. 1 was superseded by the E.C. No. 2, made under the Borland-Johnson patents, and this in its turn by the E.C. No. 3 (in 1897).
[Footnote A: Invented in 1869 by Major Le Boulengé, Belgian Artillery. It is intended to record the mean velocity between any two points, and from its simplicity and accuracy is largely employed. Other forms have been invented by Capt. Bréger, French Artillerie de la Marine, and Capt. Holden, R.A.]
~Indurite~ is the invention of Professor C.E. Munroe, of the U.S. Naval Torpedo Station. It is made from insoluble nitro-cotton, treated in a particular manner by steam, and mixed with nitro-benzene. The Dupont powder is very similar to Indurite. M.E. Leonard, of the United States, invented a powder consisting of 75 parts of nitro-glycerine, 25 parts of gun-cotton, 5 parts of lycopodium powder, and 4 parts of urea crystals dissolved in acetone. The French smokeless powder, Vielle poudre (poudre B), used in the Lebel rifle, is a mixture of nitro-cellulose and tannin, mixed with barium and potassium nitrates. It gives a very feeble report, and very little bluish smoke. The Nobel Company is said to be perfecting a smokeless powder in which the chief ingredients are nitro-amido- and tri- nitro-benzene. C.O. Lundholm has patented (U.S. Pat, 701,591, 1901) a smokeless powder containing nitro-glycerine 30, nitro-cellulose 60, diamyl phthalate 10 (or diamyl phthalate 5, and mineral jelly 5). The diamyl phthalate is added, with or without the mineral jelly to nitro-glycerine and nitro-cellulose.
~Walsrode Powder.~—The smokeless powder known as Walsrode powder consists of absolutely pure gelatinised nitro-cellulose, grained by a chemical not a mechanical process, consequently the grains do not need facing with gelatine to prevent their breaking up, as is the case with many nitro powders. For this same reason, as well as from the method of getting rid of the solvent used, the Walsrode has no tendency whatever to absorb moisture. In fact, it can lie in water for several days, and when taken out and dried again at a moderate temperature will be found as good as before. Nor is it influenced by heat, whether dry or damp, and it can be stored for years without being in the least affected. It is claimed also that it heats the barrels of guns much less than black powder, and does not injure them.
The standard charge is 30 grains, and it is claimed that with this charge Walsrode powder will prove second to none. A large cap is necessary, as the grains of this powder are very hard, and require a large flame to properly ignite them. In loading cartridges for sporting purposes, an extra felt wad is required to compensate for the small space occupied by the charge; but for military use the powder can be left quite loose. The gas pressure of this powder is low (in several military rifles only one- half that of other nitros), and the recoil consequently small; and it is claimed that with the slight increase of the charge (from 29 to 30 grs.) both penetration and initial velocity will be largely increased, whilst the gas pressure and recoil will not be greater.
This powder was used at Bisley, at the National Rifle Association's Meeting, with satisfactory results. It is made by the Walsrode Smokeless and Waterproof Gunpowder Company. The nitro-cotton is gelatinised by means of acetic ether, and the skin produced retards burning. The nitro-cotton is mixed with acetic ether, and when the gelatinisation has taken place, the plastic mass is forced through holes in a metal plate into strips, which are then cut up into pieces the size of grains. The M.H. Walsrode powder is a leaflet powder, light in colour, about 40 grains of which give a muzzle velocity of 1,350 feet and a pressure of 3 tons. It is, like the other Walsrode powders, waterproof and heat-proof.