Vegetable StaUcks. 135 
But to return to the fubjeft of the mo- 
tion of the fap ; when the fap has firft pafl'ed 
thro* that thick and fine ftrain'er, the bark of 
the roof, we then find it in greateft quanti- 
ties, in the moft lax part, between the bark 
and wood, and that the fame thro* the whole 
tree. And if in the earl)^ spring, the Oak 
and feveral other trees were to be examined 
near the top and bottom, when the fap firft 
begins to move, fo as to make the bark ea- 
fily run, or peel off, I believe it would be 
found, that the lower bark is firft moiftened 5 
whereas the bark of the top branches ought 
firft to be moiftened, if the fap defeends by 
the bark : As to the Vine, I am pretty well 
affured that the lower bark is firft moiftened. 
We fee in many of the foregoing Expe- 
riments, what quantities of moifture trees 
do daily imbibe and perfpirc : Now the ce- 
lerity of the fap muft be very great, if that 
quantity of moifture muft, moft of it, at 
cend to the top of the tree, then defeend, 
and afeend again, before it is carried off by 
perlpiration. 
The defed of a circulation in vegetables 
feems in fome meafure to be fupplied by 
the much greater quantity of liquor, which 
IC 4 the 
