504 
ME. E. A. ABEL’S CONTRIBUTIONS TO 
described is simply due to the suddenness of the development and application of physical 
force. The following are some of the more important facts of this kind : — 
1. The circumstance that the explosion of mercuric fulminate accomplished the deto- 
nation of gun-cotton, whereas explosive agents less sudden in their action failed to 
furnish this result, appeared to render it probable that silver-fulminate, which explodes 
more suddenly and with much more powerful local force when applied under the same 
conditions, would accomplish the detonation of gun-cotton more readily than the mer- 
cury-compound, i. e. it was anticipated that a larger amount of the latter would be 
needed, than of silver-fulminate, to produce the desired effect. This proved, however, 
not to be the case ; though apparently not inferior, the silver compound is in no way 
superior to that of the mercuric fulminate. The minimum quantity of the latter which 
can be relied upon to detonate compressed gun-cotton is 0324 grm. (5 grains), and it is 
necessary to enclose that quantity in a case of stout sheet metal, and to place it in close 
contact with the gun-cotton in order to obtain the desired result (see page 499). 0324 
grm. (5 grains) of silver-fulminate enclosed in tin-foil, though it appeared to produce 
quite as sharp a detonation as the corresponding quantity of mercury-salt confined in 
the stout case, did not explode gun-cotton with which it was closely surrounded, but 
merely shattered and dispersed the mass. But when enclosed in the stout sheet-metal 
cap, the 03 grm. of silver-fulminate accomplished the detonation of gun-cotton. 
2. Iodide of nitrogen, as one of the most sensitive and, apparently, violently explosive 
compounds with which we are acquainted, was next experimented with. The suscepti- 
bility to sudden explosion even of silver-fulminate will not bear comparison with that 
of the iodide of nitrogen or of the corresponding chlorine compound, though, as regards 
the mechanical effect of the explosion ( i . e. its local destructive action) both of those 
compounds accomplished decidedly less work than the silver-fulminate under the same 
conditions (see page 508). 
Many unsuccessful attempts have been made to explode gun-cotton through the 
agency of iodide of nitrogen. Pellets of this substance (weighing about 0-2 grm. and 
0-35 grm.'*), resting upon paper or thin cardboard, were carefully placed, when perfectly 
dry, upon compressed gun-cotton, and were then exploded by being touched with the end 
of a long rod ; the compact masses of gun-cotton Avere more or less disintegrated by the 
explosions, but no detonation resulted. Indications having been obtained that the vio- 
lence 'of explosion of the iodide was decidedly increased by its confinement (see p. 492), 
two descriptions of small shells charged with the substance were prepared. About 1 grm. 
of the iodide was placed, while moist, in a small cup of plaster of Paris, a spherical mass 
of the plaster was then formed round this, so that after a time the explosive agent was 
enclosed in a hard shell, the walls of which were about 0-3 inch in thickness. The 
shells thus produced were confined for several days in proximity to a desiccating agent, 
until it was found by trial of the shells that the perfect desiccation of the iodide of 
* The weights of the masses of iodide of nitrogen used, were estimated hy first ascertaining the average loss 
sustained, hy desiccation of the substance after gentle pressure between bibulous paper, and making allowance 
for this loss in the quantities of iodide set aside to dry for experiment. 
