THE HISTORY OF EXPLOSIVE AGENTS. 
349 
that length and diameter : a perfect detonation was in one instance produced when this 
charge was used in a tube only 9 inches long ; but in others, with tubes of this length 
and diameter, the detonation was also only partial. 
Through a tube only 6 inches long detonation was accomplished by means of 108 
grains (7 grms.) of fulminate; but the result was doubtful with 100 grains (6'5 grms.). 
It therefore appears that in order to accomplish the detonation of gun-cotton through 
the medium of transmission afforded by a narrow tube, at a distance of not more than 
6 inches, it is necessary to use at least fifty times the quantity of fulminate, strongly 
confined, which is required to ensure detonation when the “ detonator” is in close con- 
tact with the charge. This result presents a marked contrast to the fact demonstrated 
by the experiments described in the transmission of the detonation of gun-cotton from 
one mass to. another, through the agency of tubes, — that the detonation of 05 ounce 
(14-2 grms.) of compressed gun-cotton will induce that of another mass of gun-cotton 
if separated from it by a tube, of a particular diameter and thickness, 2 feet in length, 
the distance which thus separates the two masses being about ninety times greater than 
that through which the detonation of O' 5 ounce of gun-cotton, exposed in all directions, 
could accomplish the explosion of another mass of the compressed material. 
If, however, the quantity of confined mercuric fulminate employed as the initiative 
charge be increased not very considerably beyond that (154 grains=10 grms.) which 
is only just sufficient to detonate gun-cotton through a tube 1 inch ( - 025 m.) in 
diameter and 9 inches long, very different results are obtained. 219 grains (0'5 ounce 
or 14-2 grms.) of confined fulminate were employed, in the first instance, in 
conjunction with tubes of T25 inch ('031 m.) diameter and 2 feet long, and the 
detonation of gun-cotton inserted in the opposite extremity of the tube was accom- 
plished; on gradually increasing the length of the tubes (of the same diameter) 
employed, it was found, moreover, that the above quantity of fulminate would induce 
the detonation, with certainty, of gun-cotton through a tube jive feet long, in which 
the same quantity of compressed gun-cotton would only induce detonation of the same 
substance, under the same conditions, through a distance of two feet (‘608 m.). The 
power of the fulminate to develop detonation by transmission through considerable 
distances was still more strikingly demonstrated. Two tubes of the same diameter 
(1*25 inch) and substance, one of them 5 feet (1*52 m.) and the other 1 foot 
(*304 m.) long, were placed on the ground end to end, so as to form a channel 6 feet 
(T82 m.) long. The two ends of the tubes were brought together as closely as 
possible, and they were then covered with a piece of paper, over which was heaped a 
little sand. The confined charge of 0-5 ounce (14 grms.) of fulminate was inserted 
into the open end of the 1-foot tube, and a disk of gun-cotton into the far extremity of 
the 5-foot tube. The latter was not detonated, but shattered and partly inflamed by 
the detonation of the fulminate ; but on employing 1 ounce (28 grms.) of fulminate 
and substituting a tube 2 feet (’608 m.) long for . the 1-foot tube, so that the total 
length of the channel was 7 feet (2T m.), the detonation of the gun-cotton was 
