ME. ABEL'S RESEAECHES ON GUN-COTTON. 



285 



Several of the specimens of gun-cotton obtained from Hirtenberg were also found to 

 contain comparatively large quantities of soluble matter, and the proportions in two or 

 three samples were very high. The following are the results obtained with those which 

 differed from the Waltham Abbey products : — 



Another Austrian specimen* contained so high a proportion soluble in alcohol and 

 ether that the yam was entirely broken up by a brief digestion with the solvent ; a 

 large quantity of nearly transparent solution was separated from it, but the proportion 

 of gun-cotton remaining insoluble could not be determined with any accuracy. A few 

 other specimens of Hirtenberg gun-cotton corresponded closely to the Waltham Abbey 

 products, as regards the proportion of soluble matter they contained. 



The character of the soluble matter extracted from the Waltham Abbey products by 

 ether and alcohol was very uniform. 



The dry extracted matter, when digested with hot alcohol alone, dissolved to a very 

 considerable extent, and a light yellow solution was obtained, which, on evaporation, 

 furnished a yellow amorphous residue, almost entirely soluble in ammonia or sodic 

 carbonate ; the neutral liquids furnishing precipitates with lead- and silver-solutions. 

 When the substance was heated with potassic hydrate, ammonia was evolved. When 

 gradually exposed to heat on platinum or bibulous paper, it first fused and then 

 deflagrated. The portion insoluble in alcohol dissolved in the ethereal mixture, the 

 solution furnishing on evaporation a semiopake film, which contracted and split up into 

 small homy particles when quite dry. The extracts from Stowmarket and Hirtenberg 

 gun-cotton contained the same product soluble in alcohol alone, and generally in about 

 the same proportion ; but in most of those instances in which the specimen had furnished 

 a considerable proportion of soluble matter, the part insoluble in alcohol yielded by solu- 

 tion in ether and alcohol, a liquid which approached in its character to photographic 

 collodion ; the film left by its evaporation being more or less tough, and nearly trans- 

 parent. In two instances very good photographs were obtained with the collodion 

 extracted from specimens of Austrian gun-cotton. 



* This specimen, when I received it, was in distilled water, in which it had been preserved for twelve 

 months. It need hardly be stated that the great solubility of the gun-cotton could not be ascribed to its 

 having been thus preserved. The water containing it was perfectly neutral, and the gun-cotton exhibited no 

 signs of having undergone change since its manufacture. A sample of Waltham Abbey gun-cotton, in which 

 the soluble matter had been determined, was placed by me in distilled water at the time that the specimen 

 above referred to was received. It has since been examined, haying been in the water fifteen months, and waa 

 found perfectly unchanged. 



MDCCCLXVI. 2 V, 



