684 APPENDIX. 



ratus, the whole carbonic acid formed during the combustion of 

 the diamonds was absorbed, and could be determined by weigh- 

 ing the several parts of the apparatus. 



1471 parts of graphite being burned in this apparatus, the 

 carbonic acid formed was found to weigh 5395. Hence it is 

 composed of 2 oxygen -f O7497 carbon. 



The diamond is much more combustible than graphite. The 

 quantity of hydrogen which it contained was not appreciable, 

 and certainly did not amount to T2 Jooth ^ tne weight of the 

 diamond. The mean of five experiments on the combustion of 

 the diamond, in which the greatest quantity of diamond burnt 

 was 21*22 grains, and the least 10*926, gave for the composition 

 of the carbonic acid formed, 



Oxygen, & : 800* or 2 



Carbon, &;* . 300*02 or 0*75005 

 It follows from these analyses of Dumas and Stas that the atomic 

 weight of carbon adopted by Liebig and his pupils in the labo- 

 ratory at Giessen is too high. Consequently, in all their ana- 

 lyses the quantity of carbon found by them in organic bodies is 

 too high, and consequently the quantity of oxygen too low. 

 Dumas has shown that in all these analyses a portion of the car- 

 bonic acid formed was allowed to escape. This partly compen- 

 sated for the excess of carbon calculated, and brought their re- 

 sults very near the truth. This loss of carbon took place in 

 four different ways. 



1. The carbon is not completely consumed from the want of 

 oxygen. 



2. The copper reduced is partly converted into carburet of 

 copper. 



3. The liquid potash in Liebig's tube allows some of the car- 

 bonic acid formed to escape. 



4. The air sucked through the apparatus carries off water 

 from the potash, and diminishes its weight. 



These observations of Dumas leave no doubt that organic 

 analysis, in its present state, is incapable of giving results, the 

 accuracy of which can be fully depended on. To bring it to the 

 requisite state of precision he proposes the following amendments : 



1. The quantity of organic matter analyzed should never be 

 less than 15 or 20 grains. 



2. After the analysis is terminated, but while the decompos- 



