THEORY AND PRACTICE. 79 



I had taken some pains to ascertain the previous 

 character of the field. Fifteen or sixteen bushels to 

 the acre, (undraiiied, and in high ridge and furrow,) 

 was the utmost crop the memory of man could furnish 

 an account of. 



The crop of Wheat came up well, looked even and 

 healthy, but not thick, throughout the succeeding 

 summer, and ripened late. The produce, when threshed 

 out, was six-and-thirty bushels, including rather more 

 than half a bushel of ' Tail/ to the acre. 



How completely the Lime had done its work, in both 

 capacities, may be judged of from the fact that on a 

 couple of acres which I retained expressly for the after 

 experiment, and sowed with Beans and then with 

 Oats, unmanured, the two succeeding years, the return 

 exhibited an utter exhaustion of the productive powers 

 of the soil, to an extent that I could hardly have be- 

 lieved, without experimental proof. 



Though it cannot be desirable to sec the practice of 

 bare fallows extended ; for it exists too much already 

 upon many soils where it might be with every advan- 

 tage substituted by green-crops ; it must yet be borne 

 in mind that it is not in the mechanical structure 

 alone that heavy soils differ from light soils; their 

 chemical difference, which is quite as great, lies in 



