83 
CHEMICAL HISTORY AND APPLIANCES OF GUN-COTTON. 
generated gases upon the first ignition of a charge of gun-cotton (and consequently the 
higher the temperature at which the decomposition of the confined gun-cotton is 
effected). It is therefore readily intelligible that the notions hitherto generally enter¬ 
tained with regard to the very noxious character of the products of explosion of gun¬ 
cotton and their powerfully corrosive action upon metals—based as these notions have 
been upon the effects observed on exploding gun-cotton in open air—have been proved 
to be erroneous by the results of actual application of gun-cotton to artillery and other 
purposes. The foregoing considerations contribute, moreover, to the ready explanation 
of the fact, established by the experiments in Austria, that the destructive effect of gun¬ 
cotton is greatly increased, within certain limits, by increasing the resistance which the 
products of explosion have to overcome before they can escape into the air. 
The conditions (of temperature, pressure, etc.) which influence the nature of the 
decomposition of gun-cotton, exert, unquestionably, a similar influence upon the nature 
of the explosion of gunpowder , and upon the mechanical effects which the products are 
capable of exerting. Observations made by the lecturer, in experiments upon the igni¬ 
tion of gunpowder in rarefied atmospheres, point to the existence of products of com¬ 
paratively complicated character among those found by the gradual decomposition of 
that material under the conditions described. The earlier investigators (G-uy-Lussac, 
Chevreul, etc.), of the products of explosion of gunpowder, represent these as being of 
a very simple character, and in harmony with the theory that gunpowder is converted 
essentially by its explosion into carbonic acid (or a mixture of that gas and carbonic 
oxide), nitrogen, and sulphide of potassium. But more recent experimenters, Bunsen 
and Schischkoff, who have made a very elaborate examination of the products which 
they obtained by the explosion of gunpowder, represent the change to be one of a very 
complicated character; fix the percentage of solid substances found at a much higher 
figure than that hitherto accepted; and show that the sulphide of potassium, which has 
been considered as the principal of these products, was only produced in very small 
proportion in their experiments. The conditions under which these chemists exploded 
the gunpowder did not, however, correspond at all in their character to those under 
w'hich guupowder is exploded in actual practice, and would, therefore, be very likely 
to furnish results greatly at variance with those produced when a charge of powder is 
fired in a gun, a shell, or a mine. That sulphide of potassium is abundantly produced, 
upon the discharge of a firearm, appears beyond doubt; it may be readily detected in 
the solid matter which remains in the barrel near the breech; it may be found depo¬ 
sited in considerable quantity near the muzzle of the arm, and there appears strong 
reason for believing that the flash of flame, observed at the mouth of a firearm upon its 
discharge, is due in part to the ignition, as it comes into contact with the air, of sulphide 
of potassium, which has been vaporized by the heat of the explosion,, and is thus mixed 
with the escaping gases. 
In comparing the effects of gun-cotton, as an explosive agent, with those of gun¬ 
powder, and in basing theories, with regard to the difference in the mechanical effects 
exerted by the two, upon the analytical results of the products of their explosion which 
have been obtained up to the present time, it is necessary to proceed with great caution, 
for exceptional results cannot form any sound basis for correct theories or tenable argu¬ 
ments. It can only lead to incorrect conclusions, which may considerably retard the 
thorough investigation of a most important subject, if the facts be ignored or lost sight 
of, that, firstly , the conditions which practically influence the nature of the products of 
the explosion of gun-cotton have a similar influence upon the change which gunpowder 
mady be made to undergo ; and that, secondly , the effect of heat upon the water pro¬ 
duced by decomposition of gun-cotton, which forms so important an element in the 
the action of this explosive, has most probably its parallel, to no unimportant extent, 
in the vaporizing eflect of heat upon the solids (especially upon sulphide of potassium) 
produced in the explosion of gunpowder. These are matters which demand their full 
share of consideration and investigation, before it can be admitted that a sufficient 
explanation of the remarkable differences between the effects of gunpowder and gun¬ 
cotton exists in the assumption, that certain products of decomposition of the former 
must be regarded entirely as Avaste matter in the material, simply because they are 
solid at ordinary temperatures. The fact that gun-cotton is entirely converted into 
gases and vapour at the moment of explosion , constitutes unquestionably one of the great 
advantages which that substance possesses over gunpowder; but it is premature, at 
