51 



** best account that the most enhghtened 

 '* in the art can give of its good effects." 



Warmth communicated by running 

 water to the grass of floated meadows, 

 cannot, I am confident, be the true cause 

 of their fertihty, for the following, amongst 

 other reasons: — In the months of May 

 and June, the grass upon floated meadows 

 grows more rapidly than at any other 

 time, and yet the water is not then upon 

 the meadows. What is absent, therefore, 

 cannot operate as a present agent; or, 

 the warmth of the water can have no effect 

 upon the grass after the removal of the 

 water ; for Mr. Marshall will not say 

 that the warmth, which he has introduced, 

 will remain with the land for the space 

 of two months. W^e must, therefore, 

 look to the agency of something which 



is 



