EVIDENCE OF HISTORY 265 



less than a field than has been systematically 

 "starved." 



Even in the matter of the chemical analysis 

 of the soil experts seldom agree. There are 

 many methods of determining the mineral 

 content of soil, all stamped with the approval 

 of official and duly qualified chemists. Mix 

 a sample of soil well, so as to insure its being 

 uniform, and ask five men, qualified for the 

 task, for an analysis. Their results will vary 

 in some instances hundreds of pounds of each 

 ingredient to an acre-foot. 



The opposing sides of the theory of "im- 

 mutable assets" both point to the famous Ag- 

 dell Field at Rothamsted as furnishing evi- 

 dence to confute each other. Thus statistics 

 are subject to the most diverse interpretation. 

 This field contains one plat where wheat has 

 been grown every fourth year in rotation 

 for more than fifty years. It contains 

 another plat where wheat has been grown 

 every year. In the first instance no fer- 

 tilizer was applied. In the second the land 

 was dressed with a "complete fertilizer" every 

 year. 



What has been the result? On the un- 

 fertilized plat the yield of grain has been 1,490 



