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XXXIV. On the ultimate analysis of vegetable and animal 
substances. By Andrew Ure, M. D. F. R. S. 
Read June 27, 1822. 
The improvements lately introduced into the analysis of 
vegetable and animal compounds, with the investigation of 
the equivalent ratios, in which their constituent elements, 
carbon, hydrogen, oxygen, and azote are associated, have 
thrown an unexpected light into this formerly obscure pro- 
vince of chemical science. While the substitution by M. Gay 
Lussac, of black oxide of copper for the chlorate of potash, 
has given peculiar facility and elegance to animal analysis, 
it may be doubted whether, in those cases, where the main 
object of inquiry is the proportion of carbon, it has not, fre- 
quently, led to fallacious results. As the quantity of this 
element is inferred from the volume of carbonic acid evolved 
in the decomposition of the organic matters, such of their 
particles as happen not to be in immediate contact with the 
cupreous oxide, will remain unconverted into carbonic acid ; 
and thus the proportion of carbon will come to be under- 
rated ; an accident which cannot occur with chlorate of potash, 
since the carbonaceous matter is here plunged in an ignited 
atmosphere of oxygen. It is probably to this cause, that we 
must refer the discrepant results in the analysis of pure sugar, 
between M. M. Gay Lussac, Thenard, and Berzelius, on 
the one hand, and Dr. Prout, on the other ; the former 
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