<Tbe SAP in 'TREES. 33 



CONCLUSION. 



IN the courfe of this paper, many particular obfervations and 

 corollaries have occurred, refpecting the motions of the fap and 

 the vegetatiori of trees ; but there ftill remain fome general con- 

 clufions to be drawn from the whole train of the experiments. 

 As to the truth of the experiments, I can have little doubt, as 

 they were all twice performed in two different years, and fome 

 of them repeated on other occafions j but the juflnefs of the 

 conclufions drawn from them muft be entirely fubmitted to the 

 determination of the Society. 



r. 



WHETHER or not all the parts of a tree bleed at once, or by 

 fucceflion, is a queftion that feems to be folved, in a fatisfactory 

 manner, by thefe trials. 



WE find the bleeding fap begins firft to flow at the root, to 

 afcend flowly xipwards, and to bleed fucceflively as it afcends, to 

 the very extremities of the tree. 



IN the year in which thefe experiments were made, the fap 

 required forty- three days, from the nth of March to the 22d 

 of April, to mount twenty feet high in the trunk of the birch ; 

 that is, upon an average, it afcended nearly fix inches each day. 

 During another year, however, the fap was found to rife twenty 

 feet, in the trunk of the fame birch, in thirty-three days ; that 

 is, from the 7th of March to the 8th of April, which was about 

 nine inches each twenty-four hours. In another year, the fame 

 birch did not begin to bleed at the ground till the ayth of March. 

 Such a variation is to be expected, as the feafons vary j and to 

 this difference in the bleeding of the fap, is to be afcribed that 

 remarkable diverfity, in the time of vernation, obferved by the 

 fame tree in different years. 



