MR. ABEL’S RESEARCHES ON GUN-COTTON. 
251 
3. If gun-cotton in closed vessels is left for protracted periods exposed to strong day- 
light and sunlight in a moist or damp condition, it is affected to a somewhat greater 
extent ; but even under these circumstances the change produced in the gun-cotton by 
several months’ exposure, is of a very trifling nature. 
4. Gun-cotton which is exposed to sunlight until a faint acid reaction has become 
developed, and is then immediately afterwards packed into boxes which are tightly 
closed, does not undergo any change during subsequent preservation in ordinary store- 
houses (as far as the experience of 3^ years has shown). 
5. Gun-cotton prepared and purified according to the prescribed system, and stored 
in the ordinarily dry condition, does not furnish any indication of alteration, beyond 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. 
6. The influence exercised upon the stability of gun-cotton of average quality, as 
obtained by strict adherence to Yon Lena’s system of manufacture, by prolonged expo- 
sure to temperatures considerably exceeding those which are experienced in tropical 
climates, is very trifling in comparison with the results recently published by continental 
experimenters relating to the effects of heat upon gun-cotton ; and it may be so per- 
fectly counteracted by very simple means, which in no way interfere with the essential 
qualities of the material, that the storage and transport of gun-cotton presents no greater 
danger, and is, under some circumstances, attended with much less risk of accident, than 
is the case with gunpowder. 
7. Perfectly pure gun-cotton, or trinitrocellulose, resists to a remarkable extent the 
destructive effects of temperatures even approaching 100° C. ; and the lower nitro- 
products of cellulose (soluble gun-cotton) are at any rate not more prone to alteration, 
when pure. The incomplete conversion of cotton into the most explosive product does, 
therefore, not of necessity result in the production of a less perfectly permanent com- 
pound than that obtained by the most perfect action of the acid-mixture. 
8. But all ordinary products of manufacture contain small proportions of organic nitro- 
genized impurities, of comparatively unstable properties, which have been formed by the 
action of nitric acid upon foreign matters retained by the cotton fibre, and which are not 
completely separated by the ordinary or even a more searching process of purification. 
It is the presence of this class of impurity in gun-cotton which first gives rise to the 
development of free acid, when the substance is exposed to the action of heat ; and it is 
the acid thus generated which eventually exerts a destructive action upon the cellulose- 
products, and thus establishes decomposition which heat materially accelerates. If the 
small quantity of acid developed from the impurity in question be neutralized as it 
becomes nascent, no injurious action upon the gun-cotton results, and the great pro- 
moting cause of the decomposition of gun-cotton by heat is removed. This result is 
readily attained by uniformly distributing through gun-cotton a small proportion of a 
carbonate, the sodic carbonate, applied in the form of solution, being best adapted to 
this purpose. 
