386 
ON THE STABILITY OF GUN-COTTON. 
BY F. A. ABEL, F.K.S. 
Until quite recently the opinion has been entertained, in all countries except Austria, 
that gun-cotton did not possess the quality of uniform permanence essential to its safe 
manufacture or to its employment in warlike or industrial operations. There can be no 
question that the variety of composition of the different specimens of gun-cotton which 
have been observed to undergo decomposition exerted a very important influence upon 
their comparative susceptibility to the effects of heat and light. 
The following is a general statement of the changes which gun-cotton, preserved in 
bottles partly or perfectly closed, has been observed to undergo by exposure to light, and 
of the nature of the products of decomposition. 
In the first instance nitrous vapours make their appearance, and the gun-cotton 
acquires considerable acidity. During this period a notable proportion of nitric acid 
accumulates, and the decomposition proceeds with increased rapidity, especially on ex¬ 
posure to sunlight. The cotton, which has now contracted a good deal, is little explosive, 
and yields to water an acid extract in which may be detected nitric acid, glucose, formic 
and oxalic acids, and cyanogen. The ultimate product of the decomposition of gun¬ 
cotton has been found to contain glucose and oxalic acid, besides a gum-like substance, 
formic acid, cyanogen, and an organic acid which is very probably pectic acid. 
The exposure of gun-cotton to heat has, by most observers, been found to accelerate 
its decomposition considerably, but here again great discrepancies are presented in the 
accounts of the behaviour of the material under the influence of different temperatures. 
The most interesting and important of recent observations upon the influence of heat on 
the stability of gun-cotton are those described by Pelouze and Maury, in their recent 
report upon Baron von Lenk’s system of manufacture. The conclusions arrived at by 
these chemists decide them in the opinion that it is dangerous to preserve gun-cotton as 
now manufactured in any considerable quantities. They argue that instances of change 
have been observed to occur under ordinary atmospheric conditions, similar to those 
established in gun-cotton at higher temperatures; that, because exposure to the latter 
had occasionally brought about spontaneous explosion, it is possible for instances of 
spontaneous decomposition at ordinary temperatures to result in explosions. 
The experiments and observations carried on at Woolwich during the last four years 
may be classed as having for their objects:— 
(1.) The determination of the influence of light and of long-protracted storage, under 
ordinary conditions as to temperature, upon the stability of gun-cotton. 
(2.) The investigation of the behaviour of gun-cotton upon exposure to artificial tem¬ 
peratures, and to such elevated natural tefnperatures as are occasionally experienced in 
particular localities. 
(3.) The examination of the influence exerted upon the stability of gun-cotton by 
special modes of preparing and preserving it. 
In opposition to the statements alluded to above, the results arrived at by the author 
tend, without exception, to the conclusion that when prepared according to the directions 
laid down by Von Lenk,* and with all due precautions for the employment of properly 
purified cotton, etc., gun-cotton may be stored for long periods without undergoing any 
change. Some of the chief points arrived at may be briefly stated as follows:— 
By strictly following out the present system of manufacture a product is obtained 
which consists of nearly pure trinitro-cellulose. In the ordinary condition of dryness 
light appears to have but the very smallest decomposing action upon this substance, an 
action which is only slightly increased by the presence of moisture. It would seem, 
therefore, that the rapid decomposition which has been observed in certain instances 
could have occurred only in those specimens which had been prepared by an imperfect 
process. Gun-cotton prepared and purified according to the prescribed system and 
stored in the ordinarily dry condition does not furnish any indication of alteration be- 
y T ond the development, shortly after it is first packed, of a slight peculiar odour, and the 
power of gradually imparting to litmus when packed with it, a pink tinge. 
* See Pharm. Journ., x.s., vol. vi. p. 74. 
