408 Original Articles. | July, 
employed in experiments. The advantages which it possesses may be 
classed as follows :— 
1. It is of uniform composition, and thus the force of the gases 
generated on explosion may be accurately estimated. 
2. It will not ignite till raised to a temperature of 300° F. (as a 
rule, the temperature must be raised much higher). This is consider- 
ably lower than the igniting point of gunpowder, but, being much 
above the heat of boiling water, it can only occur when artificially pro- 
duced by means which would render gunpowder itself lable to 
ignition. 
3. It is almost absolutely free from ash when exploded under 
pressure in a confined space. 
4. It has a very marked superiority in stability over other forms 
of gun-cotton, having been kept unaltered for fifteen years. 
One great advantage which gun-cotton possesses over gunpowder, 
and which ought to have considerable weight in any discussion of 
their comparative uses for national purposes, is, that gun-cotton is un- 
affected by water. Gunpowder in a damp atmosphere will soon be 
completely spoiled, and it cannot afterwards be restored to a service- 
able condition without being again submitted to the processes of manu- 
facture, starting almost from the commencement. Gun-cotton, on the 
contrary, although it gets damp in a moist atmosphere, rapidly returns 
to its ordinary state when exposed to air of average dryness. Com- 
plete immersion in water for an indefinite period has no injurious 
action on it, for when afterwards dried by exposure to the air, it is as 
good as ever. The absolute safety which this property would confer 
upon the magazines of forts and ships cannot be too highly urged ; 
the explosive material could be kept permanently in tanks full of 
water, in which case a lighted candle or even a red-hot shot would be 
a harmless visitant. When required for action, a centrifugal drying 
machine and a hot-water closet would supply the combatants with any 
quantity at a few hours’ notice. 
When gun-cotton is ignited in a close vessel, such as a shell or 
the chamber of a gun, it is at once converted into certain gases, the 
principal being carbonic oxide, carbonic acid, nitrogen, light carbu- 
retted hydrogen, hydrogen, and steam. The introduction of the 
hyponitric acid, a compound containing a large excess of oxygen, 
gives to the cotton a sufficient amount of this gas to reduce it com- 
pletely to the state of vapour; but although only gases are produced, 
there is not enough oxygen for their complete combustion. About 40 
per cent. are inflammable, and produce a bright flash when they emerge 
into the air from the mouth of the gun. 
Ii.—Tur Meouantics or GuN-corron. 
The mechanical application of gun-cotton may be considered to be 
due exclusively to Major-General Lenk, of the Austrian service. Pure 
gun-cotton becomes either a powerful explosive agent, or a docile per- 
former of mechanical duty, not according to any change in its compo- 
sition, or variation in its elements or their proportions, but according 
