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The under-flratum feems rather to a.£i by pl-event- 

 jng the roots of fome grafTes from penetrating too 

 deep, and by enabling them to colleifl: near the fur- 

 face, and retain whatever the elements afford for their 

 fupport; and probably alfo, by abforbing the water 

 which has done its office. 



There are fome remarkable truths to be attended 

 to:— ly?. The meadow is mofl produftive when co- 

 vered with water great part of the winter. This 

 would greatly injure common water-meadows; the 

 fertility of which depends, in great meafure, on the 

 water lying on them but. a (hort time together, and 

 then being laid dry. 2dl)'. It is mofl productive 

 where there is but little depth of foil, and the flints 

 arc nearefl the furface. Thefe circumflances, which 

 differ from common cafes, feem to point to fome 

 powerful agent in vegetation, collcfted by the water, 

 the progrefs of which is flopped by the flints, and 

 not fuffered to penetrate deep into the ground. 



It is well known, that rain water, efpecially that 

 of thunder fliowers, or water expofed to the influ- 

 ence of the atmofphere, where the elementary fire 

 or eleftrical matter abounds, is much more fertili- 

 zing than that which is drawn from a well. It is alfo 

 known, that water attracts, and is a great conductor 

 of electrical matter; and I conceive that flints, like 

 glafs, are non-conduftors, or bodies which will in 

 great meafure flop its progrefs. 



It 



