STRUCTURE OF WOOD, &C. 
And these Q*57lb. of vegetable flesh are composed of 
Carbon, free and combustible . . . . 0 OQO 
Hydrogen, free and combustible . . . . 0035 
Hydrogen and oxygen, in the necessary 
proportions for the formation of water 0 445 
0-570 
In making these estimates, I have availed myself of the 
valuation of the total quantity of carbon contained in seer- 
wood, given in the analysis of Messrs. Gay Lussac and The- 
nard ; and I have supposed the 43 per cent, of charcoal, which 
I found contained in seer- wood, to be pure carbon. 
Should it ultimately appear, that charcoal is not pure carbon, 
which is extremely probable, numerous alterations in all these 
estimates must follow, though the experiments made upon the 
woods will always retain their value. And I cannot but hope, 
that they will be frequently repeated, with such variations as 
may conduce to important discoveries. 
It will be a satisfaction to me to know that I have put into 
the hands of more skilful workmen than myself, some instru- 
ments of which they may advantageously avail themselves ; 
and to have pointed out, as well as a little smoothed, a new 
path, wherein they may walk without danger of being lost. 
Section VIIL 
Of the Quantity of Heat lost in the Carbonisation of Wood , 
In making charcoal, a considerable quantity of heat is dissi- 
pated and lost in the air ; whence it is evident, that the same 
amount of heat cannot be obtained from burning a given 
quantity of charcoal as would be furnished by the combustion 
of the wood of which it is formed; 
We can now determine, with great precision, the loss of 
heat which is inevitable in making charcoal, even when all 
possible precautions have been taken j as well as that which 
happens every day in the process employed by the charcoal- 
maker . 
■# 
I 2 
115 
Combustion 
of wood and 
of charcoal. 
