418 Mr. F. A. Abel on the Stability af Gun-cotton. [April 4, 



condemnatory of gun-cotton, have been principally founded, are to be as- 

 cribed to such variations in the nature of the material operated upon. 



Very numerous and extensive experiments and observations have been 

 carried on during the last four years at Woolwich, both with small and large 

 quantities of gun-cotton, for the purpose of completely investigating the 

 conditions by which the stability of this substance, when under the influ- 

 ence of light and heat, may be modified, and with the view of ascertaining 

 whether results recently arrived at in France apply to gun-cotton as manu- 

 factured in this country. 



The principal points which have been established by the results arrived 

 at in these investigations may be summed up as follows : — 



1. Gun-cotton produced from properly purified cotton, according to the 

 directions given by von Lenk, may be exposed to diffused daylight, either 

 in the open air or in closed vessels, for very long periods without undergoing 

 any change. The preservation of the material for 3^ years under those 

 conditions has been perfect. 



2. Long-continued exposure of the substance in a condition of ordinary 

 dryness to strong daylight and sunlight produces a very gradual change in 

 gun-cotton of the description defined above ; and therefore the statements 

 which have been published regarding the very rapid decomposition of 

 gun-cotton when exposed to the sunlight do not apply to the nearly pure 

 trinitrocellulose obtained by strictly following the system of manufacture 

 now adopted. 



3. If gun-cotton in closed vessels is left for protracted periods exposed 

 to strong dayhght or sunlight in a damp or moist 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 subse- 

 quent storage for long periods. (The present experience on this head ex- 

 tends over 3| years.) 



5. Gun-cotton prepared and purified according to the prescribed system, 

 and stored in the ordinary 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 pinkish tinge. 



6. The influence exercised upon the stabiUty of gun-cotton of average 

 quality, as obtained by strict adherence to von Lenk's system of manufac- 

 ture, by prolonged exposure 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 perfectly counteracted 

 by very simple means which in no way interfere with the essential qualities 



