1867.1 Mr. F. A. Abel on the Stability of Gun-cotton. 417 



April 4^, 1^7. 

 Lieutenant-General SABINE, President, in the Chair. 

 The following commumcations were read : — 



I. " Researches on Gun-cotton. — Second Memoir. On the Stability 

 of Gun-cotton/^ By F. A. Abel, F.B.S., V.P.C.S. Received 

 March 9, 1867. 



(Abstract.) 



The results of the many observations which had been instituted prior 

 to 1860 upon the behaviour of gun-cotton when exposed to diffused or 

 strong daylight, or to heat, although they agree generally with those of 

 the most recent investigations on the subject, as far as relates to the nature 

 of the products obtained at different stages of its decomposition, cannot be 

 regarded as having a direct bearing upon the question of the stability of 

 gun-cotton produced by strictly pursuing the system of manufacture 

 prescribed by von Lenk, inasmuch as it has been shown that the products 

 formerly experimented upon by different chemists varied very considerably 

 in composition. 



The investigations recently published by Pelouze and Maury*, into the 

 composition of gun-cotton, and the influence exerted by light and heat upon 

 its stability, are described as having been conducted with gun-cotton pre- 

 pared according to von Lenk's system. The general conclusion arrived at by 

 those chemists with reference to the latter branch of the subject was to the 

 effect that the material is susceptible of spontaneous decomposition, under 

 conditions which may possibly be fulfilled in its storage and application to 

 technical and warlike purposes ; and the inference is drawn, partly from the 

 results of earlier investigators, and partly from the exceptional behaviour of 

 one or two specimens, that gun-cotton is liable to explode spontaneously at 

 very low temperatures when stored in considerable quantities. 



It has been shown, in the memoir on the Manufacture and Composition 

 of Gun-cotton, published last yearf, that modifications in the processes of 

 conversion and purification, which appear at first sight of very trifling 

 nature, exert most important influences upon the composition and purity of 

 the product. Gun-cotton of quite exceptional character has been discovered, 

 in several instances, among samples received from Hirtenberg and among 

 the first supplies obtained from Stowmarket ; other exceptional products 

 have also been produced by purposely modifying, in several ways, the sys- 

 tem of manufacture as pursued at Waltham Abbey. The very consider- 

 able difference exhibited between some of these and the ordinary products 

 in their behaviour under equal conditions of exposure to heat and light, 

 affords good grounds for the belief that the attainment of certain excep- 

 tional results, upon which the conclusions of Pelouze and Maury's report, 



* Comptes Eendus. t Trans. Eoyal Society. 



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