308 CAMBPELI/S SOIL CULTURE MANUAL 



inches of top soil. Further experiment showed him that 

 it defeated the very end it was designed to promote, in- 

 creasing the movement of moisture from below up into the 

 compacted stratum, where it speedily passed off by eva- 

 poration. While perfectly true that a plowed field that 

 has been rolled shows the presence of considerably -more 

 moisture near the surface that can be found in one that 

 is due solely to the exhaustion of the supply that has per- 

 colated down into the subsoil. That supply is needed far 

 more urgently to carry the growing crop over the pro- 

 tracted heat and probable drouth of summer than to aid 

 in the germination of seed. The use of the roller, therefore, 

 was abandoned, as promoting the early exhaustion rather 

 than the conservation of moisture. 



In 1885, he designed his first sub-soil packer, constructed 

 somewhat after the form of a grain drill, with teeth, or pack- 

 ing devices that slanted backward, penetrating the soil to 

 a depth of several inches, tending to squeeze the earth be- 

 tween them closer together. This gave encouraging re- 

 sults as a crop producer, and frequent tests of the soil, com- 

 pared with tests of adjacent lands not thus packed, proved 

 that it did conserve the moisture, although not as efficiently 

 as was desirable. The use of this implement proved im- 

 practicable, for the reason that the friction was too great 

 and it required too much power to work it to render it ad- 

 aptable for general farm use. Nevertheless, the experi- 

 ments made with it were of great value, proving that the 

 packing of the sub-soil (not of the surface) would conserve 

 ^he moisture. 



To give the record of the hundreds of experiments that 

 have been conducted since 1885 would not now be possible. 

 Even if possible, that record would be tedious, uninterest- 

 ing and unimportant. Equally unimportant would be an 



