





i 



Vegetable Statlch. 



18 



favour of the eminent Mr. Wife. This 

 vine was prepared with a cover, as the Sun- 

 flower was. Its grcateft perfpiration in u 

 hours day, was 6 ounces + 240 grains ; its 

 middle perfpiration 5 ounces + 240 grains 

 to 91 cubick inches. 

 The furface of its leaves was i82ofquarc 

 inches, or 12 fquare feet -(- 92 fquare 

 inches, whence dividing 91 cubick inches, 

 by the area of the leaves, it is found that 

 -r? T part of an inch depth, pcrfpires off in 



12 hours day. 



The area of a tranfverfc cut of its ftem, 

 was equal to •? of a fquare inch : hence the 

 fap'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 the fap's 

 motion in the Item is == VA a —3% inches 

 in twelve hours. 



This is fuppofing the ftem 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 

 .y of the ftem 5 hence the cavity thro' which 

 the fap partes, being fo much narrowed, its 

 velocity will be 4 times as great, vm% 152 

 inches in 12 hours. 



But 





