no 



Vegetable Statkks. 



Experiment XXXIX. 





\ 





In order to try if I could perceive the 

 ftcm of the Vine dilate and contract with 

 heat or cold, wet or dry, a bleeding or not 

 bleeding fcafon, fome time in February, \ 

 fixt to the ftem of a Vine an inftrumentin 

 fuch a manner , that if the Stem had dilat- 

 ed or contracted but the one hundredth 

 part of an inch , it would have made the 

 end of the inftrument, (which was a piece of 

 ftrong brafs-wire, eighteen inches long) rife 

 or fall very fcnfibly about one tenth of an 

 inch ;, but I could not perceive the inftru- 

 ment to move, either by heat or cold, a 

 bleeding or not bleeding feafon. Yet 

 whenever it rained the ftcm dilated foasto 

 raife the end of the inftrument or lever -h 

 of an inch, and when the ftem was dry 

 it fubftded as much. 



This Experiment mews, that the fap (even 

 in the bleeding feafon) is confined in its pro- 

 per vclTels, and that it does not confufedly 

 pervade every intcrftice of the ftem, as the 

 rain does, which entering at the perfpiring 

 pores, foaks into the intcrfticcs, and there- 

 by dilates the ftem. 



CHAP. 









