Vegetable Staticks. 143 
to give its fap the rapid motion which was 
neceffary for the blood of animals. 
In animals, it is the heart which fets the 
blood in motion, and makes it continually 
circulate 5 but in vegetables we can difco- 
ver no other caufe of the Tap’s motion, but 
the ftrong attraction of the capillary fap 
veffels, affifted by the brisk undulations and 
vibrations, caufed by the Sun’s warmth, 
whereby the fap is carried up to the top of 
the tailed trees, and is there perfpired off 
thro’ the leaves : But when the furface of 
the tree is greatly diminifhed by the lofs of 
its leaves, then alfo the perfpiration and 
motion of the fap is proportionably dimi- 
nifhed, as is plain from many of the fore- 
going Experiments : So that the afcending 
velocity of the fap is principally accelerated 
by the plentiful perfpiration of the leaves, 
thereby making room for the fine capillary 
veffels to exert their vaftly attracting power, 
which perfpiration is effected by the brisk 
rarifying vibrations of warmth : A power 
that does not feem to be any ways well 
adapted, to make the fap defcend from 
the tops of vegetables by different veffels 
to the root. 
If 
