858 
MR. E. A. ABEL’S CONTRIBUTIONS TO 
3. The results furnished by mercuric fulminate, when applied to the detonation of 
gun-cotton through tubes, showed that the effects produced by the detonation of a 
particular substance upon other explosive bodies may vary very importantly with the 
quantity of material detonated. Thus, when mercuric fulminate was employed in as 
large a quantity as 10 grms., it did not detonate gun-cotton with certainty through a 
tube *225 m. (9 inches) long and *025 m. (1 inch) in diameter, and 7 grms. were 
required to develop detonation through a tube T5 m. (6 inches) long; but double 
that quantity (14 grms. =0 '5 ounce) transmitted detonation to gun-cotton through a tube 
T52 m. (60 inches) long. The latter result (i. e . when an initiative detonation of 
sufficient magnitude was developed) demonstrated that gun-cotton is much more sus- 
ceptible of detonation at a distance, through the medium of a tube, by mercuric fulminate 
than by gun-cotton itself, as 14 grms. of the latter would only have developed the 
detonation of gun-cotton through about one fifth the distance under the same con- 
ditions ; but when the detonation of smaller quantities of fulminate was applied, the 
result was reversed, the sensitiveness of gun-cotton to detonation by the fulminate being 
diminished to a remarkable extent. Thus the amount of the latter required to transmit 
detonation through a tube - 31 m. (12 inches) long was more than two thirds the quantity 
required for transmission of detonation to gun-cotton five times that distance, and 
about eighty times the quantity required to develop detonation when applied in close 
contact with the gun-cotton. 
4. The experiments with gun-cotton and mercuric fulminate furnished, moreover, 
another instance, analogous to that of nitroglycerine and gun-cotton, of a want of reci- 
procity in the sensitiveness of two explosive agents to the concussions or vibrations 
which they develop. 10 grms. of the fulminate would not always develop detonation of 
gun-cotton through a tube - 31 m. (12 inches) long and - 025 m. (1 inch) in diameter, 
and 14 grms. were required to induce detonation through a distance of 5 feet ; while 
7 grms. of gun-cotton amply sufficed to develop the detonation of fulminate through 
a tube of the same diameter but 2T m. (7 feet) long, and having moreover a complete 
break in its continuity. Both nitroglycerine and mercuric fulminate are therefore far 
more susceptible of detonation by gun-cotton than the latter is prone to detonation by 
the vibrations which they develop. 
5. When the conditions essential to the transmission of detonation are only on the 
verge of being fulfilled, or when some slight accidental impediment has arisen, a result 
is frequently produced which is intermediate between the sudden explosion distinguished 
as detonation, and simple mechanical disintegration and dispersion of the material 
(accompanied occasionally by inflammation of the particles). 
IV.— DEVELOPMENT OE DETONATION, AS DISTINGUISHED EROM EXPLOSION. 
In the preceding experiments many instances occurred in which the mass of gun- 
cotton operated upon was exploded with comparatively little destructive effect, portions 
being at the same time dispersed and occasionally inflamed. Similarly, the mercuric 
