DRY-FARMING 



and, further, that these lands would never 

 yield large crops again. Mr. Campbell 

 was convinced that this was a false 

 notion, and that the true explanation — 

 the key to the problem — would be found 

 in a better and a more scientific system of 

 soil culture. It was not until the year 

 1892 that any definite results were 

 obtained. This was a period of great ac- 

 tivity in the study of the soil, and Camp- 

 bell was able to make use of the 

 investigations of Hilgard of California, 

 of King and Goff in Wisconsin, and of 

 the illuminating writings of Roberts and 

 Bailey of Cornell. 



The Sub-surface Packer. 



The invention of the Campbell sub- 

 surface packer may be traced to a simple 

 observation. In very dry seasons Mr. 

 Campbell 'perceived that the growth of 

 the grain was always better and thriftier 

 148 



