57^ STATE BOARD OF AGRICULTURE. 



quite appreciable are due to tlie variation in the moisture couteut. Al- 

 though the successive iucreameut of water added to the same amount of 

 soil were accurately measured, yet during the preparation of the sample 

 the loss of water tliat occurred, was undoubtedly not exactly equal in all 

 cases. At the lower magnitude of moisture content small inequalities in 

 percentage of water make tremendous differences in the depressions. 

 It is not surprising, therefore, to obtain the most marked disagreement 

 between the observed and calculated values at the lowest percentages of 

 water content. Since these results, therefore, follow the geometric 

 progression law, the similar data and conclusions in the first investiga- 

 tion also stand confirmed. 



This second investigation, like the first one, has shown thus far, there- 

 fore, that: (1) at a very low moisture content the lowering of the freezing 

 point is extraordinarily high and quite different in the various types of 

 soil, being lowest in the sandy types and highest in the clayey types; (2) 

 at very high moisture content, however, the freezing-point depression is 

 relatively very small and appreciably different for the diverse classes of 

 soil; (3) in all the different soils with the exception of quartz sand and 

 possibly of some extreme types of sand, the depression of the freezing 

 point increases in a geometric progression while the percentage of water 

 content decreases in an arithmetic progression ; in the case of quartz 

 sand, however, the depression increases directly proportionally as the 

 percentage of water decreases; (4) the magnitude of concentration in 

 p. p. m. and of osmotic pressure in atmospheres that the lowering of the 

 freezing point represents at the low moisture content are tremendously 

 high, especially in the complex types of soil, but at the high water con- 

 tent, they are comparatively low. 



It will at once be admitted, therefore, that these results appear ex- 

 tremely unusual and in some respects almost incredible, and do not har- 

 monize entirely with the present views concerning the concentration of 

 the soil solution. It is almost universally believed, for instance, that 

 the soil solution of the average ordinary soils is very dilute, and accord- 

 ing to some investigators it is not only very dilute but its magnitude of 

 concentration tends to be constant and to remain the same for practically 

 all soils. The foregoing results, however, as already seen, diametrically 

 oppose these views. 



The unusual rapid increase of the depression with the decrease in the 

 percentage of moisture content and the extraordinary high lowering of 

 the freezing point at the minimum degree of water content, created some 

 doubts as to whether these depressions were really caused by the concen- 

 tration of the soil solution and not by some physical factor or factors. 

 If they were caused by some physical factors they do not represent of 

 course concentration of solution. Two physical factors which might 

 produce such results were suggested: (1) the supposed pressure with 

 which the water films are held by the soil particles; and (2) the effect of 

 the solid particles upon the freezing-point lowering. As to the first fac- 

 tor it was thought that since pressure is known to lower the freezing 

 point of water, and if the pressure of the water films increased with the 

 decrease in the moisture content, then the depression of the soils would 

 be correspondingly increased. As to the second factor it was thought 

 that possibly the solid particles themselves might influence the depres- 

 sion of the soils. 



