EXPERIMENT STATION BULLETINS. 601 



at the different days. Tims if the room temperature was 20° on one 

 day and 25° on another day the freezing point of the same distilled 

 water would be different and indeed the reading on the thermometer 

 would be greater at the highest temperature. When the room tempera- 

 ture, however, remained unchanged, exactly the same freezing point 

 of the distilled water would be obtained every day for a long time. 

 Evidently the room temperature influences the exposed mercury column. 

 This effect, however, is not the same as that due to the emergent col- 

 umn. The magnitude of the change depends upon the difference in the 

 temperature. Preliminary experiments showed that a temperature dif- 

 ference of ± 10°C caused a change of ± .020 °C on the freezing point 

 of water. If it is desired to save time by not calibrating the ther- 

 mometer too often a correction such as the above could be worked out 

 and applied to the readings obtained. In the present investigation, 

 however, the room temperature remained quite constant and it was 

 not necessary to apply a correction. 



EXPERIMENTAL DATA. 



The Lowering of the Freezing Point of Soils at Different Moisture 

 Contents; and under Other Conditions. 



In accordance with the foregoing method and the necessary precau- 

 tions mentioned, the lowering of the freezing point of a large number 

 of soils was determined. In the present paper, however, only the re- 

 sults of typical representatives of diverse classes of soil are presented 

 with the view of showing mainly the character of results that this 

 method yields. All the soils employed, with the exception of quartz 

 sand and kalolin, were taken from the field and were consequently in 

 the natural state. Since preliminary trials showed that the lowering 

 of the freezing point varied with the moisture content, it was decided 

 to measure the former in each soil at two different moisture contents, 

 low and high. These two different degrees of water content were arbi- 

 trarily chosen for purposes of comparison, and are not exactly equiv- 

 alent for the various types of soil. The low moisture content does not 

 indicate the lowest limit at which solidification would occur, for in 

 many of the soils the water content could well have been reduced con-* 

 siderably more, but at this low degree of water content the solidifi- 

 cation could be induced very readily and the readings could be abso- 

 lutely depended upon. The high moisture content may be taken to 

 represent the point of saturation. In order to secure these two extreme 

 and opposite degrees of water content, water was either added to the 

 soil, if it was not already saturated when taken from the field, or with- 

 drawn from it by spreading it in a thin layer and allowing it to lose 

 water until the desired moisture content was reached. In many cases 

 the soil as taken from the field was sufficiently dry to be used imme- 

 diately for the freezing point determination. The majority of the soils 

 presented in Table 1 were collected in the vicinity of this College, a few 

 were sent in from other counties of the State, and they all constitute 

 the upper 6-inch layer of the field. 



In order to obtain an idea as to the magnitude of concentration and 



