608 STATE BOARD OP AGRICULTURE. 



Table 4. Lowering of the Freezing Point of Various Types of Soil at Different Moisture Contents. 



The lowering of the freezing point at the different moisture contents 

 is shown in the second column of each soil. These results also follow 

 a mathematical law and indeed the geometric progression law, i. e., the 

 lowering of the freezing increases in a geometric progression, while 

 the percentage of water decreases in an arithmetic progression. The 

 agreement between the observed and calculated values of the lowering 

 of the freezing point is remarkably close, — considering the na- 

 ture of the soil medium — as shown by the last two columns 

 of each soil. The calculated values were obtained by dividing 

 one of the observed depressions by the one preceding and multiplying 

 the various lowerings of the freezing point by the ratio thus obtained. 

 Since the depressions at the higher moisture content are considered to 

 be the most accurate they were used for obtaining the ratio or constant. 

 Probably it would have been permissible to take an average of all the 

 ratios between the different values of the depression and in which case 

 the calculated values would be much closer to the observed values. If 

 the results then follow the geometric progression law they are express- 

 able by the equation D = AR^^, where D -is the depression of the freez- 

 ing point, A the first depression, R the ratio of any depression (except 

 the first) to the preceding one, and n the number of the depression. 

 According to this formula if the lowering of the freezing of a soil is 

 determined at two different moisture contents it can be calculated at 

 any other moisture content. 



The main facts brought out by the investigation thus far may be 

 summarized then, as follows: At low moisture content the lowering 

 of the freezing is extraordinarily high and very different for the various 

 types of soil, being lowest in the sandy types and highest in the clay 



