1855.] on Gunpowder^ anfl its substitutes. 103 



substituted for nitrate of potash in the manufacture of gunpowder, 

 partly because the resulting mixture is hygroscopic. — The complete 

 combustion of an explosive is another desideratum. In firing 

 cannon, a considerable portion of the charge of gunpowder is 

 always lost, by being blown out unburnt ; but this is the case to 

 a much greater extent with gun-cotton, as was experimentally 

 demonstrated. It is important also in respect to fire-arms that the 

 products of combustion should not foul or corrode the piece. 

 Gunpowder leaves a considerable residuum, which has to be sponged 

 out afterwards, but it is an alkaline salt, and has little effect upon 

 metal. Gun-cotton, on the contrary, leaves no residuum; but the 

 piece remains filled with the highly corrosive red nitrous fumes 

 which have an acid reaction. Cheapness is, of course, an im- 

 portant element in comparing the practical value of different 

 explosives ; but the calculation must be made not according to 

 the weight, but according to the propulsive force of the various 

 substances. 



This review of the qualities requisite in an explosive shows that 

 gunpowder is admirably suited to such a purpose, on account of 

 its great propulsive power with little local strain, its great safety, 

 both in manufacture and in use, and its cheapness. It has two dis- 

 advantages ; its being spoilt if wetted, and its leaving after ex- 

 plosion a quantity of solid matter. It is evident, that most of the 

 fearfully explosive substances, with which chemistry has made us 

 acquainted, are perfectly inapplicable to the projection of balls. 

 Mixtures containing chlorate of potash, though good in some respects, 

 are dangerous. Gun-cotton is the only substance that puts forth just 

 now any great pretensions, as a substitute for gunpowder ; its pro- 

 pulsive force is somewhere about three times that of an equal 

 weight of powder, and it has some other advantages, coupled however 

 with serious disadvantages. The Austrian government has lately 

 put it very fully to the test of experiment ; and that they have been 

 to some extent satisfied of its value, is attested by the fact, that a 

 considerable number of cannon, of great thickness of metal about the 

 breach, have been formed expressly with the object of employing it. 



It is said to be a modification of gun-cotton which is used ; 

 and the speaker thought it most probably Wiis either a lower 

 substitution product of cotton, or a mixture of ordinary gun-cotton 

 with some other substance. In England, experiments have some- 

 times been made with this material, and it is said to have been 

 employed with advantage for filling shells at the siege of Moultan ; 

 but on account of the many accidents that have occurred with it, it 

 finds little favour at present with our military authorities. 



Dr. Gladstone concluded, by stating, that though he considered 

 war under any circumstances to be a fearful evil, yet he wished he 

 could point out a still more efficient explosive than gunpowder ; 

 for he believed that to render war a more certain game tended to 

 indispose men to engage in it. lie was glad to be able to state. 



