478 Inquiries relative to the Structure of Wood. 



fidence in those wherein the quantities of heat manifested 

 have been the greatest. 



In the experiments Nos. 13 and 14, the wood of the 

 lime-tree, dried over a chafing-dish, was productive of 

 more heat than any other wood that I examined. 



The result, it will be seen, was for i pound of this 

 wood burned in experiment, 



No. 13 . . 39.605 pounds of water heated 180 F., and in 



No. 14 . . 40.658 " " " 



Medium . .40.1315 



In order accurately to ascertain how much water this 

 wood contained, I dried thoroughly in the stove a parcel 

 of shavings which had been previously dried over the 

 chafing-dish, and found that it still retained 6.977 per 

 cent of water. 



Therefore we may conclude that i pound of this 

 wood contains only 0.93023 pound of seerwood. 



Now, if 0.93023 pound of seerwood will heat 40.- 

 1315 pounds of water 180 F., i pound of the same 

 wood ought to heat 43.141 pounds; and I therefore 

 take this quantity of water heated 180 F. as the stand- 

 ard of the heat developed in the combustion of i pound 

 of wood perfectly dried. 



Many persons have endeavoured to account for the 

 heat manifested in the combustion of wood, by attrib- 

 uting it altogether to the charcoal contained in the wood 

 burned. 



This hypothesis we have now to examine. 



It has been seen, that 100 parts of the wood of the 

 lime-tree, perfectly dried, yielded 43.59 P arts f char- 

 coal ; consequently i pound of this wood, thoroughly 

 dried, can contain only 0.4359 pound of charcoal. 



