508 
ME. F. A. ABEL’S CONTRIBUTIONS TO 
nate, a very sharp explosion was produced instead of a dull muffled report, and the me- 
chanical effect upon the copper approached in extent that produced by corresponding 
quantities of chloride of nitrogen confined by a thin layer of water, though it was still 
much inferior to that produced by freely exposed silver-fulminate, exploded by its 
surface being touched with sulphuric acid. The destructive effect of the mercuric 
fulminate was still further increased by placing the charge in a short wide paper 
cylinder, freely open at the upper end, and with the source of heat (platinum- wire) 
buried deeply in the charge (see p. 498). But the mechanical effects produced by mer- 
curic fulminate, exposed to air and inflamed from beneath as described, were not to be 
compared to those obtained by enclosing it incases of sheet metal. 0T5 grm. (1 grain), 
thus confined, produced an effect upon the copper sheet somewhat greater than that of a 
corresponding quantity of the silver-fulminate, freely exposed ; and a charge of 0 - 32 grm. 
(5 grains), similarly confined, was about equal in violence of action to 1 grm. (15 grains) 
of the unconfined material inflamed at the base of the heap. A comparison of the 
effects of larger quantities of the several explosive agents confirmed the foregoing re- 
sults. Thus 0 - 28 grm. (4 grains) of unconfined chloride of nitrogen exerted much less 
destruction than an equal quantity of unconfined iodide of nitrogen ; but if the former 
was confined by a thin layer of water, it was considerably more violent in its action than 
a corresponding quantity of the unconfined silver-fulminate. The 0*28 grm. (4 grains) 
of mercury-salt produced no effect upon the copper support ; but a similar quantity con- 
fined in a metal tube, exerted a destructive action about equal to that of the unconfined 
silver-fulminate. 
1 grm. of iodide of nitrogen and a similar quantity of chloride of nitrogen, covered 
with a film of water, did no more work than 0’5 grm. of unconfined silver- fulminate ; and 
the effect of the latter was exceeded by that of a similar quantity of the mercury-salt 
confined in a stout sheet-metal cylinder, while 1 grm. of the latter, freely exposed but 
inflamed at the base of the heap, exerted a destructive action somewhat inferior to that 
of the enclosed chloride of nitrogen. 
It would appear, therefore, from these experiments, that, when unconfined, the vio- 
lence of explosion of chloride of nitrogen is less than that of the iodide, and that, if con- 
fined under water, it very considerably exceeds that of the exposed iodide, but falls 
very short of that exerted by unconfined silver-fulminate. It also appears that the mer- 
curic fulminate, which is much less rapidly explosive than either of the other substances, 
exerts less mechanical force than any of them, if freely open to air, and if inflamed at 
some portion of the exposed surfaces ; if ignited at the lower inner portion of the mass, 
where the part first inflamed is enclosed by the mass of the material itself, it exerts a 
destructive force little inferior to that of the chloride of nitrogen enclosed by water ; 
but if confined in a strong envelope (e. g. of sheet tin), the mercuric fulminate is greater 
in violence of action than the unconfined silver-fulminate. 
These results to a great extent confirm the correctness of the view that the readiness 
with which the detonation of gun-cotton is accomplished is in proportion to the mecha- 
