The SAP in TREES. 29 



x 



made its appearance from the circles ; and when the place 

 cicatrifed was only in part cut away, the veins would appear 

 moiftened with the fap, while the circles theinfelves remained 

 perfectly dry. Thefe appearances, I imagine, made M. DO 

 HA MEL fuppofe, that there was a diftincT: defcending fap by 

 thefe veins. Such appearances do, indeed, at fir ft fight, very 

 naturally lead to this fuppofition ; but, on farther infpecHon, 

 muft be referred to the caufe already eftablifhed, the more eafy 

 and copious flow of the fap between the circles than in the 

 circles thenifelves. 



APRIL 15% 



Thermometer, at noon, 49. ; at midnight, 48. 

 THE fourteenth incifion bled as yefterday. The fifteenth was 

 very moift, but did not bleed. 



APRIL 16. 



Thermometer, at noon, 56. ', at midnight, 50.- 

 THE fifteenth and fixteenth incifions bled this day for the 

 firft time. 



OBS. 33. In the courfe of thefe experiments, this was the firft 

 inftance in which the fap moved two feet in twenty-four 

 hours. But the thermometer, in the made, flood higher than 

 it had hitherto been, and there was bright funfhine during 

 the whole day. 



APRIL 17. 

 Thermometer, at noon, 51. ; at midnight, 47. 



APRIL 1 8. 



Thermometer, at noon, 50. ; at midnight, 47. 



DURING both thefe days the fixteenth incifion. bled ; but the 

 feventeenth, though wet, did not bleed. This feemed to be ow- 

 ing to fome vigorous young branches which led off the fap, 

 and thereby prevented its rife, for a time, in the ftem. 



APRLL 



