1 46 SCIENCE PROGRESS 



than the fattening sheep. It is not difficult to understand 

 therefore, bearing in mind that nitrogen is constantly assimi- 

 lated from the atmosphere by the clover, that the mere excessive 

 usage of the fatting pastures has led to their improvement and 

 that the difference in the contribution made by the two classes 

 of stock to the land may well have brought about the change 

 in the character of the pastures — apparently stock and land 

 have been in reciprocal relationship over a long period of 

 time. The investigation carried out by Hall and Russell appears 

 to be of special value from this point of view : by showing that 

 there is no reason to suppose that the actual soils of the two 

 kinds of pasture differ intrinsically to an extent sufficient to 

 account for the observed peculiarities and that the differences 

 are induced, in all probability, by rational usage, they have in 

 a measure foreshadowed means of improving pastures generally. 



H. E. A.] 



