THE HISTORY OF EXPLOSIVE AGENTS. 
369 
violently exploded with absolute certainty. If the compressed material be soaked in 
water until thoroughly saturated with the liquid (in which case it will absorb about 
35 per cent.), or if it be similarly saturated with oil or any other liquid, it may still be 
detonated, provided a sufficient quantity of dry gun-cotton be exploded in contact with 
it. In a series of experiments instituted with gun-cotton containing precise quantities 
of water, it was found that a compact cylinder of the air-dry material weighing 100 
grains (6*5 grms.) sufficed to develop the detonation of compressed gun-cotton containing 
as much as 17 per cent, of water, provided it was detonated in close contact with some 
portion of the moist mass. Occasional failures occurred, however ; and when the pro- 
portion of moisture was increased to 20 per cent., double the quantity of dry gun-cotton 
(200 grains=13 grms.) did not suffice to develop detonation, the result being certain 
only when about one ounce (28 grms.) of dry material was employed as the initiative 
detonator. When the gun-cotton had absorbed the maximum amount of water (30-35 
per cent.) its detonation could not be absolutely relied upon with the employment of 
less than about four ounces (112 grms.) of air-dry gun-cotton applied in close contact. 
On comparing the susceptibility of moist or wet compressed gun-cotton to detonation 
by confined mercuric fulminate and by dry compressed gun-cotton, freely exposed and 
exploded by means of the usual “ detonator,” the results were decidedly in favour of 
gun-cotton as the initiative agent. Thus with 12 per cent, of water the moist sub- 
stance was only detonated once in seven experiments by a “ detonator ” containing 
100 grains (6*5 grms.) of fulminate, whereas no failure ever occurred in detonating 
gun-cotton, containing that proportion of water, with 100 grains of the air-dry mate- 
rial ; moveover the latter sufficed to produce detonation when the proportion of water 
amounted to 17 per cent., whereas this result could not be obtained with 150 grains 
(9*75 grms.) of fulminate, and appeared to be certain only when the detonating charge 
was about 200 grains (13 grms.). 
The transmission of detonation from dry gun-cotton to a moist disk, through the 
agency of a tube, appears to take place, so far as two or three experiments showed, 
with the same facility as though the mass to be detonated were dry. One ounce of 
gun-cotton, exploded in one extremity of wrought-iron tubes 1*25 inch (-031 m.) diameter 
and 2 feet (*608 m.) long, induced the detonation of moist disks, containing 15 per cent, 
of water, inserted in the other extremity ; and with a stronger tube of the same dimen- 
sions the detonation was, in one instance, transmitted to a distance of 3 feet. These 
results are quite parallel to those obtained with dry gun-cotton. 
The propagation of the detonation of moist gun-cotton from one mass to another in 
open air, the pieces being ranged in a row, in contact with each other, takes place 
apparently with as much facility as with the dry material, provided the piece first deto- 
nated contain not less water than the others to which detonation is to be transmitted* ; 
but this is not the case if even very small spaces be allowed to intervene between the 
individual masses, as l shown by the following experiments. 
* For an interesting result bearing on this point see page 382 (footnote). 
MDCCCLXXIV. 3 C 
