514 



STATE BOARD OF AGRICULTURE. 



There appear to exist no direct experimental data as to whether or not 

 there really is a translocation of moisture in soil at night, due to upward 

 movement of the moist warm air, and the condensation of its moisture at 

 the cold soil above. Practically all our present knowledge upon the sub- 

 ject consists of theoretical deductions and from practical observations. 



With the object of obtaining experimental evidence upon the subject 

 the following investigation was performed : Into brass tubes 8 inches 

 long and li/o inches in diameter was placed moist soil at one end and dry 

 soil at the other, and the two columns separated by an air space. This 

 air space was I/4 i^^ch in height and l^/o inches in diameter and was pro- 

 duced by placing between the two columns of soil a ring of cork the two 

 sides of which were closed with wire gauze which acted as supports of 

 the two soils and prevented their particles from coming in contact. The 

 tubes were then placed horizontally in the boxes shown in figure 1. That 

 part of the tubes which contained the moist soil was kept at 20° and 40° 

 C, and the part which contained the dry soil was maintained at 0° C. 

 The experiment was allowed to run about 8 hours. If during this period 

 the dry and cold soil gained any moisture it obtained it by the condensa- 

 tion of vapor which was produced at the warm and moist soil. Since the 

 dry soil possesses a high absorbtive power for water it was assumed that 

 it abstracted the vapor from the air space and that this air space was 

 thus prevented from attaining an equilibrium. There were five different 

 classes of soils used, quartz sand, Miami light sandy loam, Miami silt 

 loam, Clyde silt loam, and Miami clay. The moisture contents employed 

 for each soil were three low, medium, and high. The results obtained 

 are presented in table 3. The percentage of moisture moved from the warm 

 and moist column of soil to the cold and dry column of soil represents 

 the difference between the percentages of moisture found in the dry soil 

 at the beginning and end of the experiment. 



TABLE 3.— PERCENTAGE OF MOISTURE MOVED FROM WARM AND MOIST COLUMN 

 OF SOIL TO COLD AND DRY COLUMN OF SOIL WITH AN AIR SPACE BETWEEN THE 

 TWO COLUMNS. 



