Inquiries relative to the Structure of Wood. 447 



From the piece of wood taken from the tree on the 

 8th of September, I had 14.19 grammes of thin shav- 

 ings planed off, which, after they had been thoroughly 

 dried in the stove, weighed only 7.35 grammes. Hence 

 we have, as the constituent parts of a cubic inch of this 

 wood : 



Ligneous parts 0.26489 cubic inch. 



Sap 0.36546 



Air 0.36965 



1. 00000 



From the results of these two experiments, we may 

 conclude that the body of the tree contains more sap in 

 the winter than in summer, and more air in summer 

 than in winter. But the following experiments demon- 

 strate the sap to be very disproportionately distributed 

 in the several parts of the same tree, at the same season. 



On the 8th of September, I had a branch, about 3 

 inches in diameter, cut from the lime just spoken of, 

 and which issued from the trunk at the height of 10 feet 

 above the surface of the earth. From the lower end of 

 this branch I took a piece of wood, and subjected it 

 to the investigation requisite to ascertain its constituent 

 parts. 



Its specific gravity was 70,201. The same day I found 

 the specific gravity of a piece of the trunk of the same 

 tree to be 75,820. 



Surprising as this difference appeared, my astonish- 

 ment was still more excited, on finding that a piece of 

 wood of three years' growth, cut from the upper end of 

 the same branch, where it was but one inch in diameter, 

 had a specific gravity of 85,240. 



There was, therefore, much more sap and less air in 



