1 8 p r egetable Stanch. 



favour of the eminent Mr. IFife. This 

 vine was prepared with a cover, as the Sun- 

 flower was. Its greatcft perfpiration in u 

 hours day, was 6 ounces 4- 240 grains 5 its 

 middle perfpiration 5 ounces -\- 240 grains 

 :zz: to 91 cubick inches. 



The fur face of its leaves was i8 2ofquarc 

 inches, or 12 fquare feet 4- 92 fquare 

 inches ; whence dividing 97 cubick inches, 

 by the area of the leaves, it is found that 

 i4t part of an inch depth, perfpires off ia 

 12 hours day. 



The area of a tranfverfe cut of its ftem, 

 \vas equal to f of a fquare inch : hence the 

 lap's velocity here to its velocity on the fur- 

 face of the leaves, will be as 1820 x 4 =. 

 7280 : 1 . Then the real velocity of thefap's 

 motion in the llem is = 2 i%\~ = 3$ inches 

 in twelve hours. 



This is fuppofing the (tern to be a hollow 

 tube : but by drying a large vine branch (in 

 the chimney corner) which I cut off, in the 

 .bleeding feafon, I found the folid parts were 

 £ of the Rem 5 hence the cavity thro' which 

 the fap paffes, being fo much narrowed, its 

 velocity will be 4 times as great, vi&. 152 

 inches in 12 hours. 



But 



