350 
MR. E. A. ABEL’S CONTRIBUTIONS TO 
accomplished, although the break in the channel, at the part where the two tubes were 
placed end to end, must undoubtedly have presented a great outlet of force transmitted, 
or a serious interruption of the gas-wave. 
The observations made by MM. Champion and Pellet, in their experiments on the 
effects of explosions of different quantities of iodide of nitrogen and mercuric fulminate 
upon series of sensitive flames, indicated that the vibrations developed by a particular 
explosive substance varied in character with the quantities exploded ; and this appears 
to receive strong confirmation from the remarkable increase in the power of inducing 
detonation exhibited by mercuric fulminate, when the quantities detonated exceed 
certain limits. 
On comparing with the foregoing results those obtained by reversing the relative 
positions of mercuric fulminate and gun-cotton, it was found that the fulminate is 
susceptible of detonation through considerable distances by comparatively small 
quantities of gun-cotton. A disk weighing 110 grains (0*25 ounce or 7T grms.) 
inserted in the extremity of a tube 5 feet (1'52 m.) long and 1-25 inch (-031 m.) in 
diameter, and exploded by means of a small detonating fuse, induced the detonation 
of the fulminate at the other extremity. The same result was obtained through a 
tube 7 feet (2T m.) long, and even when a channel of this length was constructed by 
placing two tubes, the one 5 feet and the other 2 feet long, end to end, in the manner 
already described. It was not practicable to determine the minimum quantity of gun- 
cotton required to induce the detonation of mercuric fulminate, because the mechanical 
conditions essential to detonation of the gun-cotton itself cannot be fulfilled with any 
degree of certainty when smaller quantities than about 100 grains (6*5 grms.) of the 
material are employed. 
e. Experiments with silver fulminate. 
It was considered desirable to examine into some points connected with the trans- 
mission of detonation through the agency of tubes more accurately than was possible 
with the employment of large metal tubes and considerable quantities of explosive 
materials ; with this view the silver fulminate was selected for purposes of experiment, 
as being one of the most definite and most manageable explosive compounds of highly 
sensitive character. In all the experiments, the carefully prepared and dried fulminate 
was placed in small paper boats, which were inserted into the extremities of the tubes 
used ; the initiative charges were exploded by means of a platinum wire, which was 
imbedded in the material and was suddenly raised to a red heat by the current from a 
sufficiently powerful voltaic battery. It was established, in the first instance, that the 
explosion of 0 - 5 grain (‘033 grm.) of the fulminate in the manner described, when freely 
exposed to air, induced the detonation of a corresponding quantity of exposed fulminate 
with certainty at a distance of 3 inches (-076 m.), but that the attainment of this result 
was very uncertain when the distance was increased to 4 inches (T m.). It was next 
