364 
MR. E. A. ABEL’S CONTRIBUTIONS TO 
to the system now practised, contains not less than seven per cent, of lower nitro-com- 
pounds, so that even somewhat larger proportions than those specified of the above 
named salts would be required to completely burn the oxidizable elements. In order, 
therefore, to obtain the maximum amount of work from a given quantity of gun-cotton, 
that substance should be supplied with the additional oxygen capable of being furnished 
by even somewhat higher proportions than those named of the well-known oxidizing 
salts. Gun-cotton thus largely diluted with saline matter presents the form of very hard 
masses of uniform structure, with no tendency to lamination, if the salt is intimately 
incorporated with the finely divided or pulped fibre, and converted by powerful com- 
pression, with the aid of a saturated solution of the particular salt used, into masses of 
cylindrical or other forms, which are afterwards dried. 
A careful comparison of the susceptibility to detonation of these compressed mixtures 
of gun-cotton and oxidizing salts, with that of simple compressed gun-cotton, has shown 
them to be on an equality with the latter in this respect. Detonators containing only 
1 grain (-065 grm.) of mercuric fulminate, when inserted so as to fit tightly into perfora- 
tions in cylinders consisting of ordinary gun-cotton and of the mixtures above described, 
never developed detonation by their explosion ; the compressed masses were scattered ; 
in the case of the simple gun-cotton ignition sometimes occurred, and always when the 
potassium-chlorate mixtures were tried ; no instance of ignition occurred with cylinders 
of the “ nitrate ” mixtures. When detonators containing 2 grains (-13 grm.) of fulmi- 
nate were employed in the same way, not only the pure gun-cotton cylinders, but also 
those consisting of the “nitrate” and “ chlorate” mixtures were invariably detonated. 
To compare with the foregoing results, some compressed cylinders, quite similar in 
density and hardness to those of the “ nitrate ” and “ chlorate ” mixtures, were prepared 
by substituting an inert salt (potassium chloride) for the other salts in corresponding 
proportions. The detonation of these could not be accomplished by means of deto- 
nators containing 2 grains of mercuric fulminate, which sufficed in the preceding 
experiments; but they were exploded with certainty by means of 3 grains (T92 grm.) 
of the fulminate. 
The conclusions deduced from these results are as follows : — 
1. Gun-cotton may be largely diluted with a non-explosive and perfectly inert solid 
substance with but little diminution of its sensitiveness, provided the mixture is in the 
mechanical condition most favourable to its detonation. If the explosive compound is 
thoroughly incorporated with a soluble salt, the mixture being then compressed into 
compact masses with the aid of the solvent (water) and dried, the material is obtained 
in a condition of greater rigidity, and therefore in a form more readily susceptible to 
the detonating effect of a small charge of fulminate, than can be attained by submitting 
the undiluted gun-cotton to considerable greater compression, because the crystallization 
of the salt, upon evaporation of the solvent, cements the particles composing the mass 
most intimately together. Hence the reduction in sensitiveness, due to the dilution of 
the explosive compound, is nearly counterbalanced by the greater rigidity imparted to 
the mass. 
