96 



cipal cause of its durability ; and that 

 article is much more abundant, near and 

 even upon the surface, than farther within . 

 the wood, as it was the situation of the 

 principal sap-vessels, the year before the 

 tree was taken down. The quantity of the 

 article is clearly observable by the naked 

 eye, in the sun, after the wood has been 

 disbarked and somewhat dried, but much 

 better with the assistance of glasses; in 

 wdiich case, it appears so cxtremel}^ full of 

 resin, that it is very easy to conceive it 

 impenetrable by moisture, and hence the 

 particular sort »f durability now noticed. 



The result of the foregoing observations, 

 very naturally led me to a careful exami- 

 nation of the state of a Larch Post, which 

 had laid " unheeded by," since the 3'ear 

 1800, which, if my information be correct, 

 had previously been in the ground upwards 

 of twent}^ years. Hitherto it had been 

 observed, that every part of it which had 



