324 On the Quaniiti/ of Carton i?i Carbonic Acid, &c» 



The experiments of Giiyton, as detailed in the Annates de 

 Chimie, vol. xxxi. page 76, are liable to very strong ob- 

 jections ; but at the same time the candid manner in which 

 he has related every circumstance merits considerable praise. 

 It is impossible, however, not to observe, that the quantity 

 of gas before and after the experiment could not, from the 

 construction of his apparatus, be very rigorously ascertained. 

 Wc object also to nitrous gas as a test for oxygen ; and as 

 it is acknowledged that the wooden support included in the 

 oxygen gas took fire, the product of carbonic acid must 

 have been influenced by it j so that, if no chance of error 

 had existed in estimatins; the carbonic acid eras from the 

 residuum after baryiic water had absorbed a part, still the 

 result would not have been satisfactory. 



The experiments which we have had the honour of laying 

 before this society prove several important points : 



1st.. That the estimate given by Lavoisier, of 28 parts of 

 carbon in every 100 parts of carbonic acid, is very nearly 

 correct; the mean of our experiments makes it 28*C0. 



2dlv. That the diamond is pure carbon ; for, had it con- 

 tained any notable proportion of hydrogen, it must have 

 been discovered, either by detonating with the oxvgen, as 

 In the case of anims-l charcoal, or by diminishing the quan- 

 tity of oxvgen gas. 



odiy. That well burnt charcoal contains no sensible quan- 

 tity of hvdrofjen ; but if exposed to the air for a few hours 

 it absorbs moisture, which renders the results uncertain. 



'ithly. That charcoal can no longer be considered as an 

 oxide of carbon, because, wheii properly prepared, it re- 

 quires quite as much oxygen for its combustion as the dia- 

 nif)nd. This is also the case with stone coal and plumbago. 



olhly. It appears that diamond and all carbonaceous sub- 

 stances (as far as our present methods of analysis are capable 

 of demonstrating their nature) difier principally from each 

 other in the stale of aggregation of their particles. Berthollet 

 has well remarked, that in proportion as this is stronger, 

 decomposition is more difficult : and hence the variety of 

 temperatures required for the combustion of different in- 

 ■flanunablc substances. 



XLVIII. Me- 



