ON THE APPLICATION OF GUN-COTTON TO WARLIKE PURPOSES. 5 
be remembered that in 100 Ibs. of useful gunpowder this is 68 Ibs., it will 
appear that a portion of the 32 lbs. of useful gunpowder gas must be employed 
in impelling a 68 lb, shot composed of the refuse of gunpowder itself. 
There is yet another peculiar feature of gun-cotton : it can be exploded in 
any quantity instantaneously. This was once considered its great fault ; but 
it was only a fault when we were ignorant of the means to make that velocity 
anything we pleased. General von Lenk has discovered the means of giving 
gun-cotton any velocity of explosion that is required, by merely varying the 
mechanical arrangements under which it is used. Gun-cotton in his hands 
has any speed of explosion, from 1 foot per second to 1 foot in zoos of a 
second, or to instantaneity. The instantaneous explosion of a large quantity 
of gun-cotton is made use of when it is required to produce destructive effects 
on the surrounding material. The slow combustion is made use of when it 
is required to produce manageable power, as in the case of gunnery. It is 
plain, therefore, that if we can explode a large mass instantaneously, we get 
out of the gases so exploded the greatest possible power, because all the gas 
is generated before motion commences, and this is the condition of maximum 
effect. It is found that the condition necessary to produce instantaneous 
and complete explosion is the absolute perfection of closeness of the chamber 
containing the gun-cotton. The reason of this is, that the first ignited gases 
must penetrate the whole mass of the cotton; and this they do (and create 
complete ignition throughout) only under pressure. This pressure need not 
be great. For example, a barrel-load of gun-cotton will produce little effect 
and very slow combustion when out of the barrel, but instantaneous and 
powerful explosion when shut up within it. 
On the other hand, if we desire gun-cotton to produce mechanical work and 
not destruction of materials, we must provide for its slower combustion. It 
must be distributed and opened out mechanically, so as to occupy a larger 
space, and in this state it can be made to act even more slowly than gun- 
powder ; and the exact limit for purposes of artillery General yon Lenk has 
found by critical experiments. In general it is found that the proportion of 
11 Ibs. of gun-cotton, occupying 1 cubic foot of space, produces a greater 
force than gunpowder (of which from 50 to 60 lbs. occupy the same space), 
and a force of the nature required for ordinary artillery. But each gun and 
each kind of projectile requires a certain density of cartridge. Practically 
gun-cotton is most effective in guns when used as 1 to 1 weight of powder, 
and occupying a space of 11,th of the length of the powder cartridge, and 
of such density that 11 lbs. occupy a cubic foot. 
The mechanical structure of the cartridge is of high importance, as affecting 
its ignition. The cartridge is formed of a mechanical arrangement of spun 
cords; and the distribution of these, the place and manner of ignition, the 
form and proportion of the cartridge, all affect the time of complete ignition. 
(A. 19. L. 22.) It is by the complete mastery he has gained over all these 
minute points that General Lenk is enabled to give to the action of gun- 
cotton on the projectile any law of force he pleases. 
Even at the present high price of cotton, its cost of production is said 
to be less than that of gunpowder, the price of quantities being compared 
which will produce equal effects. (L. 20.) 
Practical Applications. 
Gun-cotton is used for artillery in the form of thread or spun yarn. In 
this simple form it will conduct combustion slowly in the open air at a 
rate of not more than 1 foot per second. This thread is woven into-a 
