410 Original Articles. [ July, 
arrangement alone. Why a straight cotton thread should burn with 
a slow creeping motion when laid out straight, and with a rapid one 
when wound round in a cord, and again much faster when closed in 
from the air, is far from obvious at first sight; but the facts being so, 
deserve mature consideration. 
The cartridge of a common rifle in gun-cotton is nothing more 
than a piece of match-line in the second form enclosed in a stout paper- 
tube, to prevent it being rammed down like powder. The ramming 
down, which is essential to the effective action of gunpowder, is fatal 
to that of gun-cotton. To get useful work out of a gun-cotton rifle, 
the shot must on no account be rammed down, but simply transferred 
to its place. Air left in a gunpowder barrel is often supposed to 
burst the gun; in a gun-cotton barrel, it only mitigates the effect of 
the charge. The object of enclosing the gun-cotton charge in a hard 
strong pasteboard cartridge, is to keep the cotton from compression 
and give it room to do its work. 
It is a fourth discovery of General Lenk, that to enable gun-cotton 
to perform its work in artillery practice, the one thing to be done is to 
“give it room.” Don’t press it together—don’t cram it into small 
bulk! give it at least as much room as gunpowder in the gun, even 
though there be only one-third or one-fourth of the quantity (measured 
by weight). 1b. of gun-cotton will carry a shot as far as 3 or 4 Ibs. 
of gunpowder ; but that pound should have at least a space of 160 
cubic inches in which to work. 
This law rules the practical application of gun-cotton to artillery. 
A cartridge must not be compact, it must be spread out or expanded 
to the full room it requires. For this purpose, a hollow space is pre- 
served in the centre of the cartridge by some means or other. The 
best means is to use a hollow thin wooden tube to form a core; this 
tube should be as long as to leave-a sufficient space behind the shot 
for the gun-cotton. On this long core the simple cotton yarn is wound 
round like thread on a bobbin, and sufficiently thick to fill the cham- 
ber of the gun ; indeed, a lady’s bobbin of cotton thread is the innocent 
type of the most destructive power of modern times—only the wood 
in the bobbin must be small in quantity in proportion to the gun- 
cotton in the charge. There is no other precaution requisite except 
to enclose the whole in the usual flannel bag. 
The artillerist who uses gun-cotton has therefore a tolerably 
simple task to perform if he merely wants gun-cotton to do the duty 
of gunpowder. He has only to occupy the same space as the gun- 
powder with one-fourth of the weight of gun-cotton made up in the 
bobbin as described, and he will fire the same shot at the same speed. 
This is speaking 1 in a general way, for it may: were in some guns as 
much as } of the weight of gunpowder and +; the bulk of charge to 
do the same work ; a little experience will settle the exact point, and 
greater experience may enable the gun-cotton to exceed the per- 
formance of the gunpowder in every way. 
The fifth principle in the use of gun-cotton is that involved in its 
application to bursting uses. The miner wants the stratum of coal 
torn from its bed, or the fragment of ore riven from its lair ; the civil 
