Vegetable Staticks. i \ 



viz. 2160 fquare inches, the quotient is near- 

 ly ' part of a cubick inch perfpired off a 

 fquare inch in twenty-four hours. Therefore 

 in equal furfaces, and equal times, the man 

 perfpires-f 6 , the plant T £ T , or as 50 : 15. 



Which excefs in the man is occafioned 

 by the very different degrees of heat in each : 

 For the heat of the plant cannot be greater 

 than the heat of the circumambient air, 

 which heat in Summer is from 25 to 35 de- 

 grees above the freezing point, (vide Exp. 

 20.) but the heat of the warmeft external 

 parts of a man's body is 54 fuch degrees, 

 and the heat of the blood 64 degrees -, 

 which is nearly equal to water heated to 

 fuch a degree as a man can well b,ear to hold 

 his hand in, ftirring it about ; which heat is 

 fufficient to make a plentiful evaporation. 



$u. Since then the perfpirations of equal 

 areas in a man and a Sun-flower, are to each 

 other as 1 65 : 50, or as 3 ^ : 1 ; and fmce the 

 degrees of heat areas 2:1, muftnot the turn 

 or quantity of the areas of the pores lying 

 jn equal furfaces, in the man and Sun-flower, 

 be as 1 4. : 1 ? for it feems that the quantities 

 of the evaporated fluid will be as the degrees 

 of heat, and the fum of the areas of the pore?, 

 taken together. Dr. 



