The SAP in 7 RE ES. 13 



the cafe, the eccentricity is to be afcribed to a different and 

 more general caufe, which is pointed out in the above experi- 

 ment. 



FOR as there is a more copious flow of the fap on the fouth than 

 on the north fide of trees, owing to the one being more in the 

 fun, and the other in the made, this muft naturally affect the 

 fhape of their trunks ; the fap on the fouth fide being more 

 plentiful, there the growth of the wood muft, of courfe, be 

 more confiderable. And this again fuggefts the reafon, why 

 the wood on the north fide of a large tree is often found 

 harder and more durable than that on the fouth fide ; becaufe 

 it is of a flower growth, and confequently of a more eompaxfl- 

 ed fubflance. 



MARCH 21. 

 Thermometer, at noon, 48. ; at midnight, 43. 



Thermometer, at noon, in the fun, 60. 

 THE feventh incifion bled to-day for the firft time ; the eighth 



was a little moift, but all above it were ftill dry. 



OBS. ii. So far up as the tree bled, which was now fix feet, the 

 bark feparated eafily from the wood, and a great deal of moi- 

 flure appeared between them. Above this, the fpace between 

 the wood and bark grew gradually drier, and the bark was, 

 with more difficulty, feparable from the wood. Upon many 

 trials, it was found, that, in the birch, the bark feparates from 

 the wood upon the fap's afcent, and not before; nor any 

 higher than where the fap will ftream upon incifion; and 

 that wherever the tree will bleed, there the bark not only 

 parts eafily from the wood, but the epidermis feparates rea- 

 dily from the bark, the teguments of the bark from one ano- 

 ther, the alburnum both from bark and wood, and even the 

 ligneous circles are rendered eafy to be detached from one 

 another. 



COR. 6, 



