Ij4 Vegetable Statich. 
induced to think there was, from fevcrai 
earious obfervations and experiments, which 
evidently prove, that the fap does in fome 
meafure recede from the top towards the 
lower parts of plants, whence they were 
with good probability of reafon induced to 
think that the fap circulated. 
The likelieft method effcdually and con- 
vincingly to determine this difficulty, whe- 
ther the fap circulates or not, would be by 
ocular infpe&ion, if that could be attained : 
And I fee no reafon we have to defpair of 
it, fince by the great quantities imbibed and 
pcrfpired, we have good ground to think, 
that the progreffive motion of the fap is 
eonfidcrable in the largeft fap vdfels of the 
tranfparent ftems of leaves : And if our eyes, 
alfifted with microfcopcs, could come at this 
defirable fight, I make no doubt but that 
we fhould fee the fap which was progreffive 
in the heat of the day, would on the com- 
ing on of the cool evening, and the falling 
dew, be retrograde in the fame veffcls. 
CHAP. 
