THE HISTOEY OE EXPLOSIVE AGENTS. 
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inflamed. The experiment was repeated with this difference, that the gun-cotton yarn 
was inserted into the end of the tube simply in the form of a loose and light plug ; in 
this instance, also, the loose gun-cotton was detonated. The resistance to mechanical 
motion offered by the mass, supported by the sides of the tube, was sufficient, as opposed 
to the sudden rush of gas, to ensure the detonation of the loose material. In one 
experiment a piece of yarn, which formed part of the gun-cotton plug, was allowed to 
protrude outside the tube ; this portion was projected in the air in a burning state, 
while the plug contained in the extremity of the tube was detonated. 
The successive though practically simultaneous detonation of several distinct and 
somewhat widely separated masses of gun-cotton, through the agency of tubes, affords 
further demonstration of the great rapidity with which force is transmitted by these 
means. One or two instances will suffice as illustrations. A tube 1-25 inch (-031 m.) 
in diameter, 6 feet 6 inches (2 metres) long, had a disk weighing 1 ounce (3T2 grms.) 
inserted to a distance of 2 feet (-608 m.) from each extremity; similar disks were also 
just inserted into the openings ; thus the tube contained four charges, each one sepa- 
rated from the nearest by a distance of 2 feet. On the detonation of the disk at one 
extremity only one explosion was heard ; but all the charges were detonated, the tube 
being rent into many pieces. 
A tube of the same diameter as the foregoing, but 10 feet in length, had four 
openings bored into it at intervals of 2 feet, into which were fitted short branch-pipes 
(1 inch in diameter) at right angles to the main tube. One ounce of gun-cotton was 
inserted into the latter, opposite each opening, and also into its open ends ; half an 
ounce of gun-cotton was also inserted into the extremity of each branch-pipe. The 
arrangement therefore included ten distinct charges ; those in the main pipe were sepa- 
rated from the nearest by spaces of 2 feet, and those in the branch-pipes were 1 foot 
distant from the corresponding charge in the long tube.. Just as in the preceding- 
experiment, only one sharp explosion was heard when the disk at one extremity of the 
main tube was detonated ; all the disks were exploded, the action being apparently 
instantaneous. The tubes were rent into many and curiously contorted fragments, 
which were projected to considerable distances; and small craters were formed, in the 
ground on which the tube-arrangement rested, at the seat of each charge. 
These results rendered it a matter of considerable interest to endeavour to determine 
the velocity with which detonation is transmitted from mass to mass through the 
medium of tubes, and to compare it with that at which detonation is transmitted, in 
open air, by contiguous masses of gun-cotton. The results obtained will be given 
hereafter *. 
* Numerous practical exemplifications of this mode of transmitting detonation have been obtained both with 
gun-cotton and dynamite ; and some decided advantages appear likely to accrue from the application of this 
mode of exploding charges to certain blasting and mining operations. Thus it is obviously possible, by suit- 
able arrangement of tubes, to fire a number of charges with the practical effect of simultaneous explosions. 
The Austrian engineers have already availed themselves usefully of this method of firing charges in the 
application of dynamite to purposes of demolition. Again, it has been demonstrated by the author, in actual 
MDCCCLXXIV. 2 Z 
