Inquiries relative to the Structure of Wood. 453 



A few examples will suffice to point out the method 

 to be pursued. 



The composition of the oak, in a growing state, at 

 the beginning of September, has been already given. In 

 order to ascertain the change which this wood under- 

 goes by the process of drying, I made the following 

 experiment. 



From a fagot of oak, 5^ inches in diameter, which, 

 covered with its bark, had been exposed- to dry in the 

 open air for eighteen months, I took a piece of rather 

 more than an inch square and 6 inches in length; it was 

 good firewood, and seemed very dry. 



This piece, after being trimmed by the joiner, weighed 

 126.2 grammes, and displaced 157.05 grammes of water ; 

 its specific gravity was consequently 80,357, and a cubic 

 inch weighed 15.939 grammes. 



Forty-three shavings of this wood, 6 inches long 

 and half an inch broad, weighed 17.9 grammes ; but 

 when thoroughly dried in the stove, they were reduced 

 to 13.7 grammes. They were therefore, prior to being 

 put into the stove, composed of 13.7 grammes of solid 

 parts that is to say, of dry or seerwood and 4.2 

 grammes of water. 



The results of this experiment indicate that too kilo- 

 grammes of this excellent firewood contained 76 kilo- 

 grammes of seerwood and 24 of water ; which is, 

 probably, the ordinary state of the best firewood sold in 

 the timber-yards of Paris, and all other places. 



Were the wood to be kept for several years in a dry 

 place, secured from the rain, it is possible that it might 

 become dry to such a degree as to contain only about 12 

 per cent of water, and 88 of seerwood. But it will 

 appear in the sequel that wood of any kind, exposed to 



