1916] 



SHULL— SOILS 



moisture content of the seeds and soils at the time the bottles were 

 opened expressed the equilibrium relation of that soil moisture 

 content. 



Since means are at hand for determining the internal force of the 

 seed at practically any moisture content, it is possible to determine 



Fig. i. — Rotator used in tr 



sxperiments, with motor and speed reducer. 



from the data the forces of the soils which are in equilibrium with 

 those of the seed. 



The principal sources of error lie in the fact that moist soils 

 and seeds cannot be handled in ordinary atmospheres without 

 some loss by evaporation during the handling, and in the fact that 

 hot-air ovens for drying are not as accurate as vacuum driers. 

 Xo claim is made for greater accuracy than these methods will 

 permit. Of course, every precaution was taken to reduce errors 

 to a minimum, and the work was done with the greatest speed 

 and accuracy possible. It is confidently believed that the results 

 to be obtained by more refined methods and more expensive 



