302 COMBUSTION OF CHARCOAL. 



State of the gas Carbonic acid gas, • • 1 1 1 0*1 cent. cub. • • 676 cub. inelio 



armr the pro- ^ • ~ 



cess. Oxigen gas 557.06 339*22 



Nitrogen gas 83*24 50*68 



1750*4 1065-9 



Composition If we calculate the composition of the carbonic acid gas 

 acid gas. from the quantity of oxigen employed to form it, we find, 



that the oxigen gas which disappeared in this process was 

 lGGj-8 — 557*1 = 1112-7 cent. cub. And deducting 7*3 

 cent, for the weight of 0*0099 of a gr. of oxigen, that ox- 

 ided the iron in the plumbago, there will remain 1105*4 

 cent. cub. [673*13 cub. in.] of oxigen gas, that entered into 

 the composition of 1710*1 cent. cub. [676 cub. in.] of car- 

 bonic acid gas. It instead of the measures of these gassCs 

 we substitute their respective weights, we find by the rule 

 100 part? con- cf proportion, that 100 parts of carbonic acid gas by Weight 

 tmu37-tit> . con tain 72*64 of oxigen, and 27*36 of carbon. 



If we calculate the composition of the acid gas frOrn the 

 weight of the plumbago burned, we find, that 0*5649 of a 

 gr. [8*722 grs.] of plumbago (deducting the iron contained 

 in- it) were employed to form 1110*1 cent. cub. [676 cub. 

 in.], or 2*0621 gr. [31*839 grs.] of carbonic acid gas. Coll- 

 ar 27 59 of sequent iy 100 parts of this acid by weight contain 27*39 

 parts of carbon, and 72*6l of oxigen. 



carbon. 



2d Experiment on the Combustion of Plumbago from 

 Cornwall. 



£d Exp. on As plumbago was the only carbonaceous substance, of all 



plumbago. j tried, that yielded neither water nor hidrogen in burning, 



I thought it necessary, to repeat the process. 

 Hesu'ts. The results were nearly the same as before. The com- 



£758 or 27-04 position of the carbonic acid gas came out 27*381 carbon, 

 per cent of car- an( j ^2*6 19 oxigen, calculating from the weight of plumbago 



burned; and 2704 of carbon, 72*96 of oxigen, calculating 



from the oxigen gas consumed. 

 Diminution of Two other trials were made, and in all there was a little 

 the gas. diminution of the oxigen by burning, owing chiefly to the 



oxidation of the iron miked with the plumbago. 



Combustion 



