564 



STATE BOARD OF AGRICULTURE. 



stirring- and then filtering the supcruatiint liquid through Chamberland- 

 Pasteur filters under pressure. A portion of this solution was used to 

 determine its lowering of the freezing point and another portion was em- 

 ployed to find its total solid matter by evaporating a definite volume of 

 it to dryness and weighing the residue. From the freezing-point de- 

 pression of the extract and its corresponding amount of solid material 

 present the concentration in p. p. m. of solution that is represented by 

 the values of the freezing-point lowering of each soil was calculated. 

 Thus, for instance, supposing that the lowering of the freezing point of 

 the solution was .009°C and the weight of the residue in 100 c. c. of the 

 solution was .020 grams. By calculation, .020 grams of solid material 

 in 100 c. c. of solution is equivalent to 200 p. p. m. of solution. Therefore, 

 200 parts of solid material in one million parts of solution caused a de- 

 pression of .009 °C. By means of this simple calculation therefor the con- 

 centration in p. p. m. that the various values of the freezing point loAver- 

 ing represent, was easily calculated. 



There were a great number of soils representing a large number of 

 types from which soil water extracts were made in order to ascertain tlie 

 relation between the magnitude of the depression and the total solid mat- 

 ter present. In Table I there are shown the results obtained on the 

 lowering of the freezing point and the w^eight in grams of solid matter in 

 100 c. c. of solution. 



Table 1. 



Comparison Between Lowering of the Freezing Point and Weight of Residue of Soil Water 



Extracts. 



Filtrates. 



Weight of 



residue per 



100 c. c. of 



solution. 



Gms. 



Kentucky Carrington loam 



Kentucky LaCrosse sandy loam . . 



Pennsylvania silt loam 



Pennsylvania silt loam 



Texas Crawford clay 



Texas brownish-black loam 



Texas Norfolk sandy loam 



California Chino silty clay loam . . 



California Holland loam 



California Oakley fine sandy loam 



Wisconsin Superior clay 



Wisconsin Miami silt loam 



Wisconsin Plainflsld fine sand. . . . 



Minnesota clay 



Minnesota sandy loam 



Minnesota sand 



Florida Prairie sand 



Florida Prairie sand 



Florida Prairie sand 



Michigan heavy silt loam 



Michigan heavy silt loam 



Michigan light clay loam 



Michigan heavy silt loam 



Michigan fine sandy loam 



Michigan sand 



Michigan fine sand 



Michigan light sandy loam 



Michigan muck 



Michigan peat 



.0127 

 .0132 

 .0075 

 .0056 

 .0236 



.0097 

 .0062 

 .0214 

 .0055 

 .0043 



.0076 

 .0146 

 .0044 

 .0185 

 .0255 



.0057 

 .0064 

 .0062 

 .0051 

 .0100 

 .0263 



.0161 

 .0101 

 .0150 

 .0094 



.0051 

 .0273 

 .0527 

 .0606 



