Chap. HI. Of Pasture of Plants. 25 



A Plant cannot feparate thefe Particles from the 

 Parts to which they adhere, without the AfMance of 

 Water, which helps to loofen them, 



And 'tis alio probable, that the Nitre of the Air 

 may be necefTary to relax this Superficies, to render 

 the prolific Particles capable of being thence disjoint 

 and this Action of the Nitre feems to be what is call'd, 

 Impregnating the Earth. 



Since the grofTer Vegetable Particles, when they 

 have pafs'd thro' a Plant, together with their moift 

 Vehicle, do fly up into the Air invifibly ; 'tis not 

 likely they fhould, fn the Earth, fall off from the 

 Superficies of the Pores, by their own Gravity : And 

 if they did fall off, they might fly away as eafily 

 before they enter'd Plants, as they do after they have 

 pafs'd thro' them ; and then a Soil might become 

 the poorer (a) for all the Culture and Stirring we 

 beftow upon it; tho' no Plants were in it; contrary 

 to Experience. 



It muft be own'd, that Water does ever carry, in 

 its Interfaces, Particles of Earth fine enough to 

 enter Roots ; becaufe I have feen, that a great Quan- 

 tity of Earth (in my Experiments) will pafs out of 

 Roots fet in Rain-water ; and tis found that Water 

 can never be, by any Art, wholly freed from its 

 earthy Charge-, therefore it muft have carry'd in 

 fome Particles of Earth along with it : But yet I 

 cannot hence conclude, that the Water did firft take 

 thefe fine Particles from the aforefaid Superficies : 

 I rather think, that they are exhal'd, together with 

 very fmall Pieces to which they adhere, and in the 

 Vapour divided by the Aereal Nitre ; and, when the 

 Vapour is condens'd, they defcend with it to replenish 



(a) But we fee it is always the richer by being frequently turn- 

 ed and expofed to the Atmofphere : Therefore Plants muft take all 

 their Pabulum from a Superficies of Parts of Earth; except what 

 may perhaps be contained in Water fine enough to enter Rooti 

 intire with the Water. 



the 



