1 i* 
STRUCTURE OF WOOD, &C. 
Combustion of According to the analyses of Messrs. Gay Lussac and The- 
charcoal. ° nar ^> lib. of dry wood contains 0 52lb. of carbon. 
If we adopt Crawford’s estimate, we shall find, that the 
combustion of 0*52lb. of carbon ought to furnish heat sufficient 
to raise 29 * g561b. of water to 180° F. 
Deducting this quantity of water from that given by the 
experiment, viz. 43*/41 lb., we shall have 13*185lb. as the 
measure of the heat produced by the combustion of the hydro- 
gen consumed in the experiment. 
From the results of this inquiry we may conclude, that if the 
heat manifested in the combustion of wood, rather more than 
two-thirds are produced by the combustion of the carbon, and 
a little less than one-third by the hydrogen consumed. 
These data supply us with an easy method of determining 
the quota of free and combustible hydrogen contained in seer- 
wood. 
According to Crawford’s estimate, which we have followed 
all along, lib. of hydrogen yields in its combustion heat 
sufficient to raise 4lOlb. of water to 180° F. j therefore, the 
13*185lb. heated to 180° in the experiment in question, must 
have required 0 0351581b. of hydrogen, which is consequently 
the amount of free and combustible hydrogen contained in lib. 
of seer- wood. 
Assuming the medium term of the results of the two ana- 
lyses of dry wood, made by Messrs. Gay Lussac and Thenard, 
lib. of seer- wood would be composed of 
Carbon . . . . 0*52lb. 
Hydrogen and oxygen, in the neces- 
sary proportions for forming water 0*48 
V 
From the results of my experiments, lib. of seer- wood is 
composed of two distinct substances, viz. 
A skeleton of charcoal, weighing 0*43lb. 
Vegetable flesh . . . . . . 0 57 
An4 
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