THE HISTORY OF EXPLOSIVE AGENTS. 
351 
ascertained, by repeated experiments, that the explosion of 0 - 6 grain (-038 grm.) of this 
particular batch of fulminate, inserted into one extremity of a stout (Bohemian) glass tube 
3 feet 3 inches (1 metre) long and 0*44 to 0-48 inch (0-011 to 0 - 012 m.) in diameter, 
induced, with certainty, the detonation of fulminate inserted into the other extremity 
of the tube. The result was repeatedly, but not always, obtained by the explosion of 
0‘5 grain (0-33 grm.) in metre-tubes of the smaller (0-011 m.) diameter. No detonation 
was induced by employing 0’4 grain (-026 grm.) of this fulminate. As in the case of the 
larger experiments with gun-cotton &c., an increase in the diameter of the tube was 
found to reduce the distance at tvhich detonation could be induced ; thus 0'6 grain of 
fulminate exploded in one extremity of a tube 3 feet 3 inches (1 metre) long and 
0-7 inch (-018 m.) in diameter did not detonate fulminate in the other extremity, while, 
as stated, the result was certain when the narrow tubes above described were employed 
under the same conditions and with portions of the same batch of fulminate. Only a 
slight increase of effect was obtained by confining the silver fulminate employed as the 
initiative agent. 0-4 grain (-026 grm.) enclosed in a copper capsule induced detonation 
through a metre-tube -0126 m. (0-5 inch) in diameter, though not invariably; that 
quantity was therefore about on an equality with 0-5 grain (-033 grm.) of the same 
fulminate exploded without close confinement *. 
The explosion of mercuric fulminate enclosed in a stout copper cap was found to be 
somewhat less effective in inducing detonation of this silver fulminate through tubes 
than a corresponding amount of the latter substance freely exposed. In one instance 
0-5 grain (-033 grm.) of the confined mercury compound induced detonation through a 
metre-tube of -0126 m. (0'5 inch) diameter, but in others detonation was only obtained 
when the tube was reduced to (3T5 inches) 0-8 metre ; and in one experiment, although 
the silver fulminate was exploded, the glass tube at the seat of this explosion was only 
broken once across, instead of being shattered into small fragments, as in all other 
instances. It would therefore appear that in this experiment only a partial detonation 
of the silver compound had been developed, a result frequently obtained in the expe- 
riments on a larger scale with other explosive agents already described. 
Comparative experiments were made on the power of transmitting detonation pos- 
sessed by tubes of equal diameter and of as nearly the same thickness as could be 
obtained, but consisting of different materials. The following is a tabulated statement 
of the results obtained : — 
* The silver fulminate, although always prepared with care by precisely the same process, was not always 
obtained of the same degree of sensitiveness. A particular series of experiments was therefore always made 
with one and the same batch of material. 
