384 
MR. E. A. ABEL’S CONTRIBUTIONS TO 
These results demonstrate conclusively that when compressed gun-cotton is saturated 
with water, so that the air in the mass is replaced entirely by the comparatively incom- 
pressible liquid, detonation is transmitted at a decidedly more rapid rate than with 
equally compact dry gun-cotton. 
d. Detonation of nitrated gun-cotton. 
The considerable amount of a nitrate required to completely utilize the oxidizable 
constituents of gun-cotton should naturally tend to reduce the rapidity of explosion of 
that substance, when employed in the form of a mixture with any proportion of salt- 
petre approaching the theoretical requirement. Results obtained by the detonation of 
“ nitrated ” gun-cotton, in practical experiments, afforded decided evidence of less rapid 
action, which Avas confirmed by determinations of the rate at which detonation is trans- 
mitted along trains of the nitrated material. The disks employed were 3 inches (0*078 m.) 
in diameter, containing about two thirds the theoretical requirement of saltpetre (namely, 
38 per cent.), and weighed about 4 ounces each. The mean velocity of detonation 
was =15,981 feet (4794*38 m.) per second, the rate of transmission generally ranging 
between 15,500 (4650 m.) and 16,000 feet (4800 m.) per second ; it was therefore about 
2000 feet per second below that of ordinary air-dry compressed gun-cotton. 
e. Detonation of dynamite. 
The material used in these experiments was that known as Nobel’s dynamite (No. 1), 
and consisted of an intimate mixture of about seventy-three parts of nitroglycerine 
Avith tAventy-seven parts of Kieselguhr *, made up into cylindrical cartridges 0*5 inch 
(0*013 m.) in diameter, and 3 inches (0*078 m.) long, by being firmly pressed into 
wrappers of stout parchment-paper. Thus prepared it resembles stiff clay, not suffi- 
ciently Avet to be very plastic. The paper envelopes Avere removed from the cartridges 
for the purpose of these experiments, and the cylindrical masses (the average weight 
of Avhich Avas 2 '3 ounces = 71*76 grms.) Avere placed end to end and pressed together; 
in this way perfectly continuous trains of dynamite, 30 feet and 42 feet (9T2 and 
12*76 m.) long, Avere prepared ; detonation Avas established by means of the ordinary 
“ detonator ” used Avith gun-cotton, Avhich was inserted into a small cartridge of dyna- 
mite or a disk of gun-cotton, and placed upon one extremity of the train. The rate at 
Avhich detonation Avas propagated Avas recorded at intervals of 4 feet and 6 feet(T21 and 
1*82 m.) along the trains; the mean velocities observed Avere 19,536 feet (5938*24 m.) 
and 21,592 feet (6563*96 m.) per second. As with gun-cotton, the rate of progression 
of the detonation Avas as high at the end of the longest train as at the commencement, 
and at one part of each of the trains it attained a velocity of 24,000 feet (7296 m.). 
These numbers sIioav that the velocity with Avhich detonation is transmitted by the 
plastic nitroglycerine mixture is decidedly higher than with dry compressed gun-cotton. 
* The dynamite was obtained from the factory of the British Dynamite Company, near Glasgow, which has 
recently been established to meet the demands for Nobel’s nitroglycerine preparations in the country. 
