GUN-COTTON. 
117 
This cotton-yarn converted into gun-cotton may be called, therefore, the raw material 
of commerce. In this form it is not at all explosive in the common sense of the word. 
You may set fire to a hank of it, and it will burn rapidly with a large flame ; but if you 
yourself keep out of the reach of the flame, and keep other combustibles beyond reach, 
no harm will happen, and no explosion or concussion will result. If you lay a long 
thread of it round your garden-walk at night, disposing it in a waving line with large 
balls of gun-cotton thread at intervals, and light one end of the thread, it will form a 
beautiful firework, the slow lambent flame creeping along with a will-o’-th’-wisp-looking 
light, only with a measured speed of 6 inches per second, or 30 feet a minute; the 
wind hastening it or retarding it as it blows with or against the line of the thread. This 
is the best way to commence an acquaintance with this interesting agent. 
Care must be taken not to become too familiar with gun-cotton even in this harmless 
and playful guise ; cotton dresses will readily catch fire from it, and it should not be 
treated with less care to keep fire from it than gunpowder. In one respect it is less 
liable to cause danger than gunpowder. Grains of powder are easily dropped through a 
crevice, and may be sprinkled about in a scarcely noticeable form; but a hank of gun¬ 
cotton is a unit, which hangs together and cannot strew itself about by accident. 
The second form of gun-cotton is an arrangement compounded out of the elementary 
yarn. It resembles the plaited cover of a riding-whip ; it is plaited round a core or 
centre which is hollow. In this form it is match-line, and, although formed merely of 
the yarn plaited into a round hollow cord, this mechanical arrangement has at once con¬ 
ferred on it the quality of speed. Instead of travelling as before only 6 inches a second, 
it now travels 6 feet a second. 
The third step in mechanical arrangement is to enclose this cord in a close outer skin 
or coating, made generally of India-rubber cloth, and in this shape it forms a kind of 
match-line, that will carry fire at a speed of from 20 to 30 feet per second. 
It is not easy to gather from these changes what is the cause which so completely 
changes the nature of the raw cotton by mechanical 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 conside¬ 
ration. 
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 gunpow¬ 
der, 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 perforin 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). 1 lb. of gun-cotton will carry a shot as far as 3 or 4 lbs. 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 preserved 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 chamber 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 
