Mr. F. A. Abel on the Stability of Gun-cotton. 547 



trifling in comparison with the results recently published by Conti- 

 nental experimenters relating to the effects of heat upon gun-cotton ; 

 and it may be so perfectly counteracted by very simple means which in 

 no way interfere with the essential qualities of the material, that the 

 storage and trausport of gun-cotton presents no greater danger, and 

 is, under some circumstances, attended with much less risk of acci- 

 dent than is the case with gunpowder. 



7. Perfectly pure gun-cotton, or trinitrocellulose, resists to a re- 

 markable extent the destructive effects of prolonged exposure to tem- 

 peratures 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 products does, therefore, not of necessity result 

 in the production of a less perfectly permanent compound than that 

 obtained by the most perfect action of the acid mixture. 



8. But all ordinary products of manufacture contain small propor- 

 tions of organic (nitrogenized) 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 com- 

 pletely 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 ex- 

 posed 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 this small quantity of acid developed from the impurity in ques- 

 tion be neutralized as it becomes nascent, no injurious action upon 

 the gun-cotton results, and a great promoting cause of the decom- 

 position of gun-cotton by heat is removed. This result is readily ob- 

 tained by uniformly distributing through gun-cotton a small pro- 

 portion of a carbonate, — the sodic carbonate, applied in the form of 

 solution, being best adapted to this purpose*. 



9. The introduction into the finished gun-cotton of 1 per cent, of 

 sodic carbonate affords to the material the power of resisting any 

 serious change, even when exposed to such elevated temperatures 

 as would induce some decomposition in the perfectly pure cellulose- 

 products. That proportion affords, therefore, security to gun-cotton 

 against any destructive effects of the highest temperatures to which 

 it is likely to be exposed even under very exceptional climatic condi- 

 tions. The only influences which the addition of that amount of 

 carbonate to gun-cotton might exert upon its properties as an ex- 

 plosive would consist in a trifling addition to the small amount of 



* The deposition of calcic and. magnesian carbonates upon the fibre of gun- 

 cotton, either by its long-continued immersion in flowing spring water, or by its 

 subjection to the so-called "sili eating" process adopted by Von Lenk, produces 

 a similar protective effect, which, however, is necessarily very variable in its 

 extent, as the amount of carbonate thus introduced into a mass of gun-cotton is 

 uncertain ; moreover, as it is only loosely deposited between the fibres, the pro- 

 portion is liable to be diminished by any manipulation to which the gun-cotton 

 may be subjected. 



