336 Journal of Agricultural Research voi. xv. no. e 



and have collected samples of soils irrespective of season, rainfall, condi- 

 tion of soil, date, and uniformity of sampling, etc., and then tried to 

 compare the absolute salt content of these soils. 



By being able now to determine the absolute salt content of soils, 

 the value and usefulness of the freezing-point method are increased 

 tremendously. This method is now able to accomplish at least two very 

 important and fundamental things: First, to determine the actual or 

 real concentration of the soil solution as it actually exists in the soil 

 from a very low to any maximum moisture content, and second, to 

 determine the absolute salt content of soils at a high moisture content. 

 It seems to be the best, most unique, and most accurate method we 

 have to-day for accomplishing these purposes. 



SUMMARY 



In the present paper the freezing-point method is presented as an 

 excellent means for determining the absolute salt content of soils with 

 a very high degree of accuracy. Formerly the method could determine 

 only the actual concentration of the soil solution as it existed in the soil 

 at different moisture contents, but now the method has been developed 

 to measure also the absolute salt content of soils and thus afford an 

 accurate comparison of the absolute salt content of soils. 



LITERATURE CITED 

 (i) BouYoucos, G. J. 



1916. THE FREEZING POINT METHOD AS A NEW MEANS OF DETERMINING THE 



NATURE OF ACIDITY AND LIME REQUIREMENT OF SOILS. Mich. Agf. 

 Exp. Sta. Tech. Bui. 27, 56 p., fig. la-yd. 



(2) 



191 7. CLASSIFICATION AND MEASUREMENT OF THE DIFFERENT FORMS OF WATER 



IN THE SOIL BY MEANS OF THE DILATOMETER METHOD. Mlch. Agr. 



Exp. Sta. Tech. Bui. 36, 48 p., 5 fig. 



(3) and McCooL, M. M. 



I916. THE FREEZING-POINT METHOD AS A NEW MEANS OF MEASURING THE 

 CONCENTRATION OF THE SOIL SOLUTION DIRECTLY IN THE SOIL. Mich. 

 Agr. Exp. Sta. Bui. 24, p. 592-631, 2 fig. ^ 



(4) 



1916. FURTHER STUDIES ON THE FREEZING POINT LOWERING OF SOILS. Mich. 



Agr. Exp. Sta. Tech. Bui. 31, 51 p. 

 (5) and Laudeman, W. A. 



1917. THE FREEZING-POINT METHOD AS A NEW MEANS OF STUDYING THE VE- 



LOCITY OF REACTION BETWEEN SOILS AND CHEMICAL AGENTS AND 



BEHAVIOR OF EQUILIBRIUM. Mich. AgT. Exp. Sta. Tech. Bui. 37, 32 p. 

 6) Cameron, F. K. 



1911. THE SOIL SOLUTION. 136 p., 3 fig. Easton, Pa. 



(7) Hoagland, D. R. 



19 18. THE freezing-point METHOD AS AN INDEX OF VACATIONS IN THE SOIL 



SOLUTION DUE TO SEASON AND CROP GROWTH. In Jouf. AgT. Research, 

 V. 12, no. 6, p. 369-395, 8 fig. Literature cited, p. 394-395. 



(8) McCooL, M. M., and Wheeting, L. C. 



1917. MOVEMENT OF SOLUBLE SALTS THROUGH SOILS. In Jouf. Agr. Research, 

 V. II, no. II, p. 531-547. 5 %• 



