802 



MR. ABEL'S RESEARCHES ON GUiV-COTTOX. 



14) obtained by treatment of the cotton for twenty-four hours are notably higher than 

 those furnished by the forty-eight hours' treatment. The loss of product ascribable 

 to this cause is doubtless somewhat greater in these experiments than in manufacturing 

 operations, when the proportion of acid to the cotton used is considerably lower*. 



A comparison of the weight of cotton, pbtained from samples of gun-cotton, with the 

 original weight of cotton employed in their production, affords data which are strongly 

 in support of the conclusion that the diiferences between the increase in weight which 

 cotton should sustain by conversion into trinitro-cellulose, 



€6H;N,0,i, 

 and the results furnished by as perfect a treatment of different specimens of cotton as is 

 practicable, are to be ascribed, not merely to the presence, in the products, of small 

 quantities of imperfectly converted soluble gun-cotton, but also to the existence in them 

 of substances which are foreign to the cotton, and which are only partially removeable 

 by simple washing with water. 



The following are the results of very careful experiments made with finely-carded 

 and specially purified cotton-wool, and with ordinary cotton-yarn, purified by boiling 

 with potassic carbonate. The increase sustained by the cotton upon its conversion into 

 gun-cotton having been noted, the product was reconverted into cotton by Hadow's 

 method, special care being taken to avoid mechanical loss in the several operations. 

 The weights of the cotton recovered compared with those of the original cotton, and 

 with the increase of weight sustained by the latter when converted into gun-cotton, are 

 as follows : — 



It will be seen from the above statement, that the cotton which was recovered fi-om 

 the laboratory products, furnished by comparatively very pure cotton which had sus- 

 tained an increase of weight of 82 and 82*6 per cent, (the theoretical increase being 



''' Upon reconversion into gun-cotton of some specimens of the reduced cotton, which is always in a friable 

 condition very favourable to solution, the weights of the resulting products indicated that a more considerable 

 proportion of the gun-cotton produced was dissolved than when the original cotton was operated upon. 



One sample sustained an increase of weight of only 73-91 per cent., and a second 73 per cent, by immersion 

 for the usual period. A third sample, submitted to a brief treatment, gave an increase of 77-61 per cent., and 

 upon being immersed a second time for twenty-four hours, the weight of the product indicated an increase of 

 only 75-15 per cent. 



