450 Inquiries relative to the Structure of Wood. 



For the more easy comparison of the results of these 

 four experiments upon the wood of the lime-tree, made 

 on the same day, with different portions of the same tree, 

 I have collected them together in the following table. 



Being desirous to ascertain whether a difference con- 

 siderable enough to be valued existed between the wood 

 of the heart, or core, and the sap-wood found between 

 the rind and the body of the same tree, I took, on the 

 nth of September, an elm fagot, 5 inches in diameter, 

 lopped from a large tree, which had been felled on the 

 2oth of the preceding April, and had two cylindrical 

 pieces, each 6 inches in length, cut out of it. The 

 thickest of these taken from the core weighed 191.05 

 grammes, and displaced 194.45 grammes of water ; the 

 other, consisting of the sap-wood, weighed 93.61 

 grammes, and displaced 111.45 grammes of water. 



The specific gravity of the core was, therefore, 98,251 ; 

 that of the sap-wood, 81,764. But as the fagot had 

 lain exposed to all the summer rains, the wood was far 

 from being dry. I was, however, much surprised at dis- 

 covering that the core of the wood was more charged 

 with sap or water than that of the same kind of wood 

 when in a growing state, a fact which induces a sus- 

 picion that the sap in trees is not enclosed in vessels 

 or tubes apparently impervious to that liquid. 



