282 Professor Brande's Observations on 



From an experiment made with Dr. Prout's apparatus the re- 

 lative proportions of carbon, nitrogen, and hydrogen, in cinchonia 

 were estimated as follows : 



Carbon 80.20 



Nitrogen 12.85 



Hydrogen 6.85 



99^90 

 In this analysis the permanently gaseous products were collected 

 at one operation, and the hydrogen was estimated by a second 

 experiment in which every product was allowed to escape from 

 the tube, and the weight of carbonic acid and nitrogen then de- 

 ducted from the entire loss. 



In a second experiment, in which Mr. Cooper's apparatus was 

 employed and in which, as in the others, he was good enough to 

 assist me, similar proportions of cinchonia and of oxide of copper, 

 were employed, but the water produced was retained in a portion 

 of the tube, cooled for the purpose, and its quantity ascertained 

 afterwards, by carefully weighing the tube, first in its original 

 state, and a second time after the entire expulsion of the water 

 by heat. The following is the result of this experiment : 



Carbon . , 78.4 



Nitrogen , 14.6 



Hydrogen 7.5 



100.5 

 Several other experiments were made chiefly with a view of 

 detecting the presence of oxygen, but that element was in no 

 instance discovered, either by any loss of Aveight, as indicated by 

 the results of destructive distillation, or indirectly, by the ap- 

 pearance of aqueous vapour in other processes of decomposition. 

 Among the latter, the effect of chlorine upon cinchonia may 

 perhaps be regarded as most satisfactory. Five grains of carefully 

 dried cinchonia, were introduced into a small exhausted retort 

 which was afterwards filled with chlorine. There was no absorp- 

 tion of the gas, nor the smallest apparent action until very consider- 



