

I 



Si Vegetable Scaticks. 



of a foot diameter ; and circles being as the 

 fquares of their diameters 10 pounds -j- 2 

 ounces, will in 21 days be evaporated from 

 the hemifphcre of 30 inches diameter, which 

 the Sunflower's root occupies : Which with 

 the 29 pounds drawn off by the Plant in 

 the fame time, makes 39 pounds, that is 9 

 pounds and \ out of every cubick foot of 

 earth/ the Plant's roots occupying more than 

 4 cubick feet ; but this is a much greater de- 

 gree of drynefs than the furfacc of the earth 

 ever furTcrs for 15 inches depth, even in the 

 . fay eft feafons in this country. 



In a long dry fcalon, therefore, efpecially 

 within the Tropicks, we mult have recourfc 

 for fufficicnt moifturc (to keep Plants and 

 Trees alive) to the moift ftrata of earth, 

 which lay next below that in which the 

 -roots are. Now moid: bodies always com- 

 municate of their moifturc to more dry 

 adjoyning bodies; but this flow motion of 



1 



f he afcent of moifturc is much accelerated 

 by the Sun's heat to confiderable depths in 

 the earth, as is probable from the following 

 20th experiment. 



Now 1 80 grains of Dew falling in one 

 pight, on a circle of a foot diameter, a=s 



1 1 3 fquarc 







