136 



Journal of Agricultural Research 



Vol. X, No. 3 



third week to the twenty-second the gain in the dry soils decreased as the 

 initial percentage increased, although for the first three weeks the soil 

 with 6.52 per cent of moisture gained most and that with an initial per- 

 centage of 8.24 gained the least water. In the soil having 8.24 per cent 

 there was hardly any appreciable gain after the sixth week. It is prob- 

 able that on account of the greater ease with which the moisture moves 

 through the moist soil such soil has its capillary demands satisfied before 

 the drier one, and consequently movement takes place for a longer time 

 in the drier soil. 



ReLafiVs disftibufi'an 'cf mcisfure af i^ar/aus fimes 

 /n t^ef secfion /n drt/ section 



^ J 



f 



>i: 



I 



7 



Line of ■sefiaraflon befn^een wet and dri^ soils 



Fig. 18. — Diagram showing the effect of varying initial percentages of water on the horizonal distribution 

 of moisture in drier soils in contact with a wet soil having 24.36 per cent of water. The top line of each 

 series represents the original distribution. 



DETERMINED BY THE DEFLECTION OP ONE END OF A LARGE SOIL COLUMN 



In this study the moist soil was placed in 6-inch glass tubes having 

 diameters of K inch. The wet soil in the one tube was held in contact 

 with the drier soil in the other by connecting the tubes with celluloid. 

 The soil used and the moisture contents for the standard wet soil and the 

 drier soil were exactly the same as in the last experiment. 



The columns formed by the tubes of wet and dry soils in contact were 

 suspended from their centers by pieces of string and were then brought 

 into an exactly horizontal position by adding weights to the lighter ends, 

 A pin was then attached to the end of the tube containing the moist soil, 

 so that as the moisture moved into the drier soil the moist end swung up 

 and scratched the paraffined surface of a glass plate. Records of these 

 scratc"hes were made weekl}' throughout the experiment, which lasted 

 from March 2i to May 8, 1916. 



