5* Vegetable Statich. 



Now fuppofing the roots of the Sun-flower 

 (the longeft of which reached 15 inches eve- 

 ry way from the ftem) to occupy and draw 

 nouriftiment from 4 cubick feet of earth, 

 and fuppofe each cubick foot of earth to 

 afford 7 pounds of moifture, before it be 

 too dry for vegetation; the plant imbibing 

 and perfpiring 22 ounces every 24 hours, 

 that will be 28 pounds of water, which will 

 be drawn off in 21 days, and 1 6 hours ; after 

 which the plant would perifh, if there were 

 not frefh fupplies to thefe 4 cubick feet of 

 earth, either from dew or moifture arifing 

 from below 15 inches (the depth of the 

 roots) up into the earth occupied by the 

 roots. ^ 



Experiment XIX. 



In order to find out the quantity of Dew 

 that fell in the night, Aug. 15. at 7. p.m. I 

 chofe two glazed earthen pans, which were 

 3 inches deep, and 12 inches diameter in 

 furface; I filled them with pretty moift earth 

 taken off the furface of the earth. I fet 

 thefe pans in other broader pans, to pre- 

 vent any moifture from the earth flicking 

 to the bottoms of them. The moifter the 

 earth, the more dew there falls on it in a 



night 7 



