COMPOSITION OF GUNPOWDER, ETC. 201 



is called granulating; and powder is sold of several degrees 

 of coarseness, commencing with No. 1, which is the finest in 

 use, and increasing in the size of the grain up to No. 5. 

 After the granulation is effected the grains are generally 

 more or less glazed by friction, in barrels which are made to 

 revolve rapidly; and, finally, the resulting dust being sifted 

 out, the powder is packed. 



As fine-grained powder explodes more rapidly than coarse 

 when not crushed, or in large quantities, it follows that it is 

 more suited for short barrels and small charges, such as, for 

 instance, in pistols or carbines. The aim, in all cases, should 

 be to use powder in such quantity and quality that the 

 whole of it is burnt just as the projectile leaves the muzzle 

 of the gun ; for if it is all converted into gas before that 

 period of time, the projectile has to overcome the friction of 

 the sides of the tube without any increasing force as it goes 

 on, and consequently loses some of its propellant power. If, 

 on,the other hand, all the powder is not burnt before the 

 projectile escapes, there is a waste of powder, and this is the 

 most frequent and the least injurious result. On firing a 

 full charge over the snow, a few grains of powder entire may 

 almost always be picked up beneath the line of flight of the 

 charge. Those, therefore, who are careful in such matters, 

 will adopt the necessary precaution to ensure the proper 

 charge of the right kind of powder for the particular gun 

 they are using. 



The desiderata, in gunpowder will therefore vary con- 

 siderably according to the charge, to the length of barrel, 

 and to the mode of firing it. In every case, however, it 

 should be clean, that is to say, it should leave no perceptible 

 residuum on firing it loosely on a piece of white paper. The 

 first test to apply is the following, which also shows that the 

 powder is dry and easily exploded : Take five or six 

 drachms of powder and divide it into two heaps, placed on a 

 piece of white paper ; then fire one of them with a red-hot 

 wire, and if the two explosions do not sound as one, the 

 powder is bad or damp ; while if any steam is left, or the 

 paper is burnt in holes, there is an imperfection somewhere. 

 The smoke, also, should be of a whitish grey. In relation to 

 the charge, the powder should be coarser according to the 



