iJG ON THE HEAT EVOLVED 



product was not found to be essentially different, but, invariably, 

 rather larger from the dry than from the green wood, and the 

 specific gravity of the former was also greater ; I have no hesi- 

 tation, however, in saying that there will be less loss in charring 

 wood in the large way by using dry w r ood, as it can be ignited 

 more equally, and w r ith greater facility. 



It is my intention, so soon as my other avocations will per- 

 mit, to make some experiments in the charring process in the 

 large way, and to use the fine coal as suggested, for which 

 purpose a number of cords of wood have been cut for a con- 

 siderable period of time. 



Dead wood w r as found to produce the same quantity of 

 charcoal as the same w r ood in a living state, and the limbs of 

 trees produced coal of much greater density than the trunk. 

 Among the most dense woods, stove dry ebony, sp. gr. 1.090, 

 gave a product of charcoal from 100 parts of wood, of 33. S2, 

 which is larger than was obtained from any other wood, and 

 its specific gravity was also greater, being .888 ; its fracture so 

 much resembles that of some of the mineral coals, that it is 

 difficult to say in what respects they differ. Stove dry live 

 oak, sp. gr. .942, gave 32.43, sp. gr. .591. Tortoise-shell 

 wood, sp. gr. 1.212, gave 30.31, sp. gr. .866. Cocoa, sp. gr. 

 1.231, gave 28.53, sp. gr. .742. Turkey box, sp. gr. .933, gave 

 27.24, sp. gr. .622. 



A piece of box wood polished, lost very little of its lustre 

 by charring in powdered coal, and the beautiful variations in 

 the grain of the wood were as apparent in the coal as in the 

 wood, and this experiment may be considered as conclusive, as 

 to the complete exclusion of air by this process. 



It does not appear from the products of charcoal from the 

 different woods, that their density or durability is to be attri- 

 buted to the quantity of carbon they contain. As the woods 

 ^lifter materially in the quantity of charcoal product by mea- 

 sure, it appeared necessary to give the product from a cord of 

 each in bushels, and as the value of these can only be deter- 

 mined by their weight, this also appeared necessary, both of 

 which will be found in the table. 



