The SAP in TREES. 31 



APRIL 30. 



Thermometer, at noon, 60. j at midnight, 52. 

 THE vernation, or budding of the tree, now took place, that 

 is, the young leaves were mot forth fo far, as to be of an equal 

 length with the hybernaculum. 



THIS day all the incifions, in the upper part of the tree, were 

 dry. A little fap ftill iffued from the four ihcifions upon the 

 trunk, that were next the ground. But frefti incifions being 

 made in different parts of the branches, they all refufed to bleed. 



MAY i. 



Thermometer, at noon, 58. j at midnight, 50. 

 ALL the incifions, both on the trunk and branches, were dry, 

 excepting one, a foot from the ground, which ftill continued 

 moift, though it did not bleed. 



COR. 20. It appears then, that the fap does firfl ceafe to flow in 

 the branches ; and that it continues, for fome little time, to 

 flow in the lower parts of the trunk, after the upper parts are 

 become dry. 



MAY 2. 



Thermometer, at noon, 60. ; at midnight, 53. 

 INCISIONS being now made over the whole tree, from the 

 root to the extremities of the branches, they were all found per- 

 fectly dry. The young leaves were now fhot forth in length, 

 confiderably beyond that of the hybernaculum. 

 OBS. 35. It feemed now natural to conclude, that the tree ceafed 

 to bleed, and that the wood was every where become dry, by 

 the evaporation occasioned by the leaves which were now 

 fhot forth. The two following experiments, however, {hew, 

 that this appearance is owing to a different caufe. 

 EXP. 13. A young birch, i| inch in diameter, was cut over at 

 the beginning of the bleeding feafon, a foot from the ground,, 

 and, on the trunk that remained, there was no bud. This 



trunk 



