CARBON. 



ways a little below the truth. The reason I 

 found to be, that a portion of the carbonic acid 

 remained in the liquid muriatic acid, and did not 

 assume the gaseous form at all. 



When acetic acid was used, the extrication of 

 gas went on very slowly, unless the carbonate of 

 lime was in powder ; and the gas extricated was 

 always below the true quantity, because it did 

 not all assume the elastic state. 



Sulphuric acid did not answer well, because 

 the sulphate of lime formed was apt to screen 

 some of the calcareous spar from the action of 

 the acid, and thus to prevent the whole gas from 

 being obtained. 



Oxalic, tartaric, and citric acids, could not be 

 used, for a similar reason. Nitric acid was ex- 

 cluded, because it acted on the mercury. 



Foiled in my attempts to determine the vo- 

 lume of carbonic acid gas extricated from a given 

 weight of calcareous spar by the above method, 

 I had recourse to another, which succeeded per- 

 fectly. 



To the beak of a small 



retort, A, I cemented 

 a long glass tube, bent 

 at right angles, at a, b, 

 and B, and the upright 

 leg, B, C, of such a 

 length, that it reached 

 very nearly to the top of the graduated glass 



