482 Inquiries relative to the Structure of Wood. 



As the combustion of i pound of charcoal, perfectly 

 dry, yields heat sufficient to boil 57.608 pounds of 

 water, at the thawing temperature ; and as I pound of 

 wood, thoroughly dry, furnishes 0.4333 pound of dry 

 charcoal, it follows, that the charcoal produced from i 

 pound of dry wood should furnish in its combustion 

 heat sufficient to boil 24.958 pounds of water, at the 

 thawing temperature. 



But we have already seen that the combustion of 

 i pound of wood, thoroughly dry, should furnish suffi- 

 cient heat to boil 43.143 pounds of water at the freezing 

 temperature ; or, which is the same thing, to raise it 

 1 80 of Fahrenheit's thermometer. 



These two numbers (43.143 and 24.958), which ex- 

 press the quantities of heat in question, being in the 

 proportion of 100 to 57.849, it is evident that the loss 

 of heat inevitable in the carbonization of wood is up- 

 wards of 42 per cent, or exactly 42.151 per cent of the 

 total quantity that the wood will furnish. 



In order to determine the loss of heat which occurs 

 in the forests, by the ordinary process of the charcoal- 

 burner, it is requisite to ascertain the precise product 

 of charcoal from a given quantity of wood, though it is 

 probable that this product is very variable. M. Proust 

 estimates it at 20 per cent in weight at the highest. 



Adopting, for a moment, this estimate, and suppos- 

 ing the carbonized wood in the same state of dryness as 

 what is usually sold for firewood ; as 100 pounds of such 

 wood contains only 0.76 pound of perfectly dry wood, 

 this quantity would furnish in its combustion only the 

 degree of heat necessary to raise 32.043 pounds of 

 water 180 F. 



But the 0.20 pound of charcoal produced by the car- 



