60li STATE BOARD OF AGRICULTURE. 



freezing point and of tlie water content are not inversely proportional, 

 (approximately), to each other as might be expected, except only in 

 quartz sand. Thus, clay at 3(5. 57o of moisture gave a depression of 

 .034°C, and at 18.80%., .955°C, the ratio of the percentage of water at 

 the two moisture contents is only 1.94, while that of the depression of 

 the freezing point is 27.11. A sandy loam, which at 21.53% of water 

 gave a depression of .020°C, and at 8.30%o, .450°C, shows a ratio of 

 2,35 in percentage of water to 22.5 in the lowering of the freezing point. 

 In the case of quartz sand, however, the ratio of the depression is di- 

 rectly inversely proportional to the water content. Thus, at 1.5% of 

 water content the depression is .070°C and at 15% it is .007°C, the 

 inverse ratio, therefore, being 10 to 10, respectively. 



Apparently, the quartz sand yields different results from all the 

 other types of soil and its data can be mathematically expressed by the 

 simple equation M.D. = K. where K is a resultant constant, M is the per- 

 centage of moisture content and D, the observed depression of the freez- 

 ing point. The following table serves to show how close the data of 

 the quartz sand follow the above formula: 



Table 3. Lowering of the Freezing Point of Quartz Sand 

 at Various Moisture Contents. 



The last column to the right contains the value or constant ob- 

 tained by multiplying the percentage of moisture by the observed lower- 

 ing of the freezing point. It will be noted that the constant K is prac- 

 tically the same at all moisture contents, which goes to prove that 

 the data of the quartz sand follow the foregoing mathematical formula 

 remarkably close. 



The same constant is obtained even when the quartz sand is treated 

 with a salt solution and allowed to dry and then determining its de- 

 pression at different moisture contents. 



The question now rises, do the results of the other types of soil also 

 follow some mathematical law, i. e., are they expressable mathematical- 

 ly? In order to obtain definite data upon this point the lowering of 

 the freezing point of a large number of soils was determined at various 

 moisture contents. The procedure consisted of allowing the soils to 

 become air dry and then adding different quantities of water to the same 

 amount of soil, allowing the mixture to stand in a moist atmosphere at 

 room temperature for about 24 hours and then determining its lower- 

 ing of the freezing point. The moisture content varied from very low 

 to very high. Great precaution was taken to moisten the whole mass 

 of each sample very uniformly. Several types of soil were used for 



