On the Chemical History of Gun-Cotton and Xyloidine. 519 



in virtue of (76.), one common symbolical ralue, namely one 

 or other of the two which are included in the ambiguous form 



v.»y 



S.»'x' + T..'x'' ^^^'' 



respecting which form it may not be useless to remark that 

 the product of its two values is unity. 

 [To be continued.] 



LXXVI. Contributions to the Chemical History ofGun-Cotton 

 and Xyloidine. By Mr. John Hall Gladstone, of Uni- 

 versity College, London^. 



A T the commencement of the present year, having perceived 

 -^^ that considerable doubt rested on the ultimate composi- 

 tion of gun-cotton, I undertook a series of experiments with 

 a view to ascertain it, if possible ; and during my investiga- 

 tion my attention was drawn to various papers that appeared 

 on the subject, where I found contradictory accounts, not 

 only of the results of analysis, but also of the action of va- 

 rious reputed solvents. The experiments detailed below, 

 although they are far from exhausting the subject, may serve 

 to explain some of these anomalies, and to point out a few 

 facts, which, as far as I have been able to learn, have not 

 been hitherto noticed. 



The cotton employed was that used by jewellers, well- 

 carded, perfectly white, and free from imperfections. An 

 analysis of the substance by combustion with oxide of copper 

 in a stream of oxygen yielded the following results : — 



Cotton employed 3*16 grs. 



Carbonic acid produced . , . 5*14 ... 



Water produced 2*06 ... 



These proportions are, — 



Carbon . . . 44-37 

 Hydrogen . . 7*24 

 Oxygen . . . 48-39 

 100-00 

 Lignine calculated from the formula C24 H20 Ogo •' — 

 Carbon . . . 44-44 

 Hydrogen . . 6-17 

 Oxygen . . . 49-39 

 100-00 

 The excess of hydrogen doubtless arises from moisture 

 absorbed by the oxide of copper during the unavoidable delay 

 in mixing it with the cotton. 



* Communicated by the Chemical Society; having been read June 7> 

 1847. 



