S3S 



left *2 gr. of 

 oxide of iron. 



Residual gas 

 increased -01, 



ON THE QUANTITY OF CARBON IN CARBONIC ACID. 



longing to Dr. Babington, were put into the tray. Our oxi- 

 gen left a residuum of 2 parts in 100, and we began with 

 49*84 cubic inches. The tray, with its contents, being 

 placed in the platina tube, was heated to redness for a quar- 

 ter of an hour, and the gas made to pass over it several 

 times. When all was cool, the original quantity was neither 

 increased nor diminished, and on withdrawing the tray we 

 found only *2 of a grain of oxide of iron ; so that this spe- 

 cimen of plumbago contains only 5 per cent oxide of iron. 

 The gas being now examined, 



Lime water absorbed 55 parts from 100 



The tests for oxigen 42 



Residuum 3or an increase of 1 percent. 



x'8 25 cubic 

 inches of car- 

 bonic acid gas 

 produced, 

 containing 

 '2846 of car- 

 ton. 



6o° 



44° 

 16 diff. 



100 



Correction for temperature. 

 01 03 

 16* 



49*84 

 1-64 



1-648 add for temp. 51*48 



Correction for pressure. 

 30: 29*94:: 51*48: 51*37. 

 The quantity of oxigen at the mean would be 51*37 cubic 

 inches. 



100:55 :: 51*37: 28*25, 



Therefore 28*25 cubic inches of carbonic acid gas were pro- 

 duced. 



100 : 47*26, : ; 28*25 : 13*35 grains. 

 13-35:3*8 :: 100:28*46. 



Then, according to this experiment, 100 grains of carbonic 

 acid contain 28*46 of the carbonaceous part of the plum- 

 bago. 



Calculation by oxigen. 

 100 : 33*82 : : 28*25 : 9*55 grains of oxiget* 

 consumed 3-?o plumbago. 



13*35 

 Calculation by carbonic acid 13.35 



First 



