330 STRUCTURE OF WOOD, 6CC. 



Sap and vola I found the specific gravity of the oak of the current year to 



llood a,t ' ^ be u6530 > that of the e]m > H0540. Young shoots of these 

 trees, deprived of their bark and pith, descend rapidly on being 

 thrown into water j whilst pieces of the same tree, moie 

 advanced in age, swim on the surface, even when the wood is 

 green, and more full of sap. 



This fact is worthy the attention of persons occupied in the 

 study of vegetable physiology. 



I was next curious to examine the root of the lime from 

 which I had already had one piece of wood from the trunk, and 

 two pieces from one of its branches. With this view, on the 

 8th of September, 1812, I caused one of its roots, of about 

 two inches diameter, to be tnken up, and cut from it a piece 

 weighing 9325 grammes, which displaced 1 15'8 grammes of 

 water. Its specific gravity was 80527, and, consequently, 

 greater than that of the wood extracted from the trunk of the 

 same tree, but less than that cut from the upper end of one of 

 its branches. 20 48 grammes of thin shavings, from this piece 

 of the root of the lime, weighed only 10*85 grammes after 

 being thoroughly dried in the stove. 



From these data, I determined the constituent parts of a 

 -cubic inch of the root, thus : 



Ligneous parts 0*28775 cubic inch. 



Sap 037358 



Air O 3386*7 



1*00000 



The constituent parts of a cubic inch of the body of the same 

 tree, were, as we have shewn : 



Ligneous parts 0*26480 cubic inch. 



Sap ". 0.36*546 



Air „ 0*36965 



1 00000 



The constituent parts of a cubic inch of the wood of the 

 same tree, taken the same day from the lower extremity of a 

 branch, were : 



Ligneons 



