M4 Vegetable Statkks. 



induced to think there was, from feveral 

 curious 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 effectually and con- 

 vincingly to determine this difficulty, whe- 

 ther the fap circulates or not, would be by 

 ocular infpeclion, if that could be attained : 

 And I fee no reafon we have to defpair of 

 ir, fince by the great quantities imbibed and 

 perfpired, we have good ground to think, 

 that the progreffive motion of the fap is 

 confiderable in the largeft fap-veffels of ther 

 tranfparent ftems of leaves : And if our eyes, 

 affifted with microfcopes, could come at this 

 defirable fight, I make no doubt but that 

 we (hould fee the fap which was progreffive 

 in the heat of day, would on the com- 

 ing on of the cool evening, and the falling 

 dew, be retrograde in the fame veflels. 



CHAP, 



