372 
ME. F. A. ABEL’S CONTRIBUTIONS TO 
It was afterwards found that a “ detonator” containing 3 grains (‘195 grm.) of dry ful- 
minate would not explode the wet fulminate or “cap-composition” when fired at a 
distance of 2 inches ( - 05 m.) from them, but did so with certainty at a distance of 
T5 inch (‘031 m.). When, instead of exploding the dry fulminate confined in a cap- 
sule or tube of sheet-tin, it was detonated by a sharp blow from a hammer (a naval 
“ gun-hammer ” being used for the purpose), the wet substance was detonated when 
just in contact with 5 grains (*32 grm.) of dry fulminate thus exploded; but it failed to 
detonate when removed to a distance of T25 inch (‘0063 m.). The detonation produced 
by means of the hammer was therefore much less violent than when the same or a 
smaller quantity of closely confined fulminate was exploded *, no doubt because particles 
of the latter escape detonation by the falling hammer, being dispelled by the rush of 
gas from the portions first exploded. 
Finely divided gun-cotton, made up into a paste or pulp with water, is not susceptible 
of explosion under conditions far more favourable than those just pointed out, which 
determine the detonation of wet mercuric fulminate. Wet gun-cotton pulp was placed 
in a cylinder of sheet-zinc open at the upper end ; a disk of compressed gun-cotton, 
coated with waterproofing material, and fitted with an ordinary “detonator” (10 grains 
of mercuric fulminate enclosed in a tube of stout sheet-tin), was inserted into the pulp, 
so as to be completely surrounded by it. The explosion of this disk only dispersed the 
pulp, scattering the fragments of the zinc cylinder. This experiment was repeated 
with the same result ; and no other effect was obtained when disks weighing 2 ounces 
(62’4 grms.) were detonated in the centre of the pulp, which was employed with various 
proportions of water. Very different effects were, however, produced by a simple modi- 
fication of the manner of carrying out these experiments, as will be presently seen. 
VI.— EMPLOYMENT OE 'WATER AS A MEANS OE TRANSMITTING DETONATION, AND OF 
APPLYING THE FORCE DEVELOPED BY EXPLOSION. 
In experiments made upon the employment of wet compressed gun-cotton in sub- 
marine mines, the charges being enclosed in stout cases of wrought iron, it was demon- 
strated not only that gun-cotton containing 30 per cent, of water might be thus as 
efficiently applied as the dry substance, but also that it is possible to detonate masses of 
wet compressed gun-cotton, surrounding the dry initiative charge, when the interstices 
between the individual masses are filled up with water. The slight compressibility of 
the liquid does obviously not present an impediment to the sufficiently sudden trans- 
mission of the force, developed by detonation, to closely contiguous masses of gun- 
cotton and to others surrounding these, if the individual masses are separated from 
each other only partly and by small quantities of water. Provided the escape of force 
by transmission through the water be retarded, at the instant of the first detonation, 
* The wet fulminate in close proximity to the dry material, which was detonated by a hammer or in a 
capsule, was always dispersed by the detonation ; hut it was collected by a receptacle surrounding the charge, 
and was thus proved not to have been exploded. 
