GUN-COTTON. 
113 
In casemates of fortresses, gunpowder fills the casemates with foul smoke, and the 
men speedily sink under the exertion of quick firing. By using gun-cotton it was 
ascertained that the men could continue their work unharmed for double the quantity of 
firing. This is partly attributed to the greater heat, and partly to the foulness of the 
air produced by gunpowder. 
But it is under the decks of our men-of-war that greatest benefit is likely to arise from 
gun-cotton. Not only does the smoke of a broadside fill the between decks with hot 
and foul air, but the smoke of the windward gun blinds the sight, and hinders the aim 
of the leeward. When there is no smoke, as with gun-cotton, the aim of every gun may 
be precise and deliberate. The diminished heat between decks will also tell powerfully 
in favour of gun-cotton. In our armour-plated ships also there is more value in breech¬ 
loading guns than in any other use of artillery. It is one of the necessities of breech- 
loading mechanism, that it be kept clean, and nothing tends more to derange its perfect 
action than the greater heat which gunpowder imparts to the gun from which it is fired. 
That gun-cotton has the convenience of not heating the gun has been thus proved:— 
100 rounds were fired in 34 minutes with gun-cotton, and the temperature of the gun 
was raised 90°. 100 rounds were fired with gunpowder, and triple the time allowed to 
bool the gun, which nevertheless was heated so much as to evaporate water with a hiss¬ 
ing sound, which indicated that its temperature was much above 212°. Under these 
circumstances the firing with gunpowder had to be stopped, while that with gun-cotton 
was comfortably continued to 180 rounds. 
It is also a matter of practical convenience that gun-cotton, insomuch as it is lighter, 
can be carried more easily and farther than gunpowder; and it may be wetted without 
danger, so that when dried again in the open air, it is as good for use as before. 
III. We have now to ask—is it cheaper ? The answer to this question must be qua¬ 
lified—pound for pound it is dearer; we must therefore judge of its cheapness by its 
effect, not by weight merely. But where it does six times as much work, it can then be 
used at six times the price per pound and still be as cheap as gunpowder. As far as we 
yet know, the prices of gun-cotton and gunpowder are nearly equal, and it is only there¬ 
fore where the one has advantages and conveniences beyond the other, and is more 
especially suited for some specific purpose, that it will have the preference. Effective 
cheapness will therefore depend mainly on which of the two does best the particular 
kind of duty required of it. 
To illustrate how curiously these two powers, gun-cotton and gunpowder, differ in 
their nature, and how the action of gun-cotton may be changed by mechanical arrange¬ 
ments, we may take one kind of work that is required of both:—If a General want to 
blow open the gates of a city, he orders an enterprising party to steal up to the gate, 
with a bag containing 100 lbs. of gunpowder, which he nails to the gate, and by a pro¬ 
per match-line he fires the gunpowder and bursts open the gate. If he nailed a bag of 
gun-cotton of equal weight in the same place and fired it, the gun-cotton would fail, 
and the gate would be uninjured, although the 100 lbs. of gun-cotton is sixfold more 
powerful than the gunpowder. Here, then, gunpowder has the advantage—both weight 
and effect considered. 
But the fault here lies not in the gun-cotton, but the way of using it. If instead 
of 100 lbs. of gun-cotton in a bag, 25 lbs. had been taken in a proper box made for this 
purpose, and simply laid down near the gate, and not even nailed to it, this 25 lbs. 
would shiver the gate into splinters. The bag which suits the powder happens not to 
suit the gun-cotton. 
Gun-cotton is therefore a power of a totally different nature from gunpowder, and re¬ 
quires complete study to know its nature and understand its use. It appears that both 
gunpowder and gun-cotton have special qualities, and may be peculiarly suited for pecu¬ 
liar uses. It is the duty of a wise people to make use of both to the ends they each 
suit best, without prejudice arising from the accident of novelty or antiquity. 
The nature of gun-cotton requires a double study, chemical and mechanical. It is 
not like steam, the same substance, whether in the form of ice or water or steam. It is 
one substance when as gun-cotton it enters the gun, and quite a different one when it 
has exploded and leaves the gun. Not only are the solids which enter converted into 
gas, but they form totally new combinations and substances. So that the marvellous 
changes which the chemist effects by the magic of his art take place in an instant of 
time, and during that almost inconceivably minute period of time, in a laboratory in- 
