EXPERIMENT STATION BULLETINS. 603 



Table 1. Osmotic Pressure in Atmospheres for Depression of the Freezing Point to 2.999^ C. 



The osmotic pressures corresponding to depressions of hundredths of 

 degrees may be read directly from the table. Furthermore, for all 

 practical purposes, the first differences x 0.1 may be taken as 0.012, 

 hence, pressures when a is read to thousandths of a degree may be at 

 once determined. Thus, suppose a to be 1.224°. For a = 1.24° pres- 

 sure = 14.92°. 14.92 (4 x 0.012) = 14.968. 



The lowering of the freezing point of various types of soils, then, at 

 two different moisture contents, together with the calculated concen- 

 tration in p. p. m. of solution and osmotic pressure in atmospheres 

 that these values of the freezing point depression might represent, are 

 shown in Table 2. 



