*>4 Vegetable Statkks. 



vigour of warm and confined vapour (luch 

 as is that which is i, 2, or 5 f eec deep in 

 the earth) muft be very considerable, fo as 

 to penetrate the roots with fome vigour; 

 as we may reafonably iuppofe, from the 

 vaft force of confined vapour in /Eolipiles, 

 in the digefter of bones, and the engine to 

 raife water by fire. See. Vol. II. p. 259. 



If plants were not in this manner fup- 

 plied with moifture, it were impoffible for 

 them to fubfifr under the fcorching heats 

 within the Tropicks, where they have no 

 rain for many months together: For tho' 

 the dews are much greater there, than in 

 thefe more Northern climates - 9 yet doubdefs, 

 where the heat fo much exceeds ours, the 

 whole quantity evaporated in a day there, 

 does as far exceed the quantity that falls 

 by night in dew, as the quantity evaporat- 

 ed here in a fummer's day, is found to ex- 

 ceed the quantity of dew which falls in the 

 night. But the dew, which falls in a hot 

 fummer feafon, cannot poffibly be of any 

 benefit to the roots of trees; becauie it is 

 remanded back from the earch by the fol- 

 lowing day's heat, before fo fmall a quantity 

 of moifture can have foaked to any con- 

 fiderable depth. The great benefit there- 

 fore 



