Aug. 28, 1916 Indirect Determination of Hygroscopic Coefficient 



835 



relationship of the moisture equivalent to the hygroscopic coefficient can 

 be computed. 



COMPUTATIONS FROM DATA OF BRIGGS AND SHANTZ 



Briggs and Shantz have reported (7, p. 57-65) both the hygroscopic 

 coefficients and the moisture equivalents in the case of 17 soils ranging 

 in texture from a coarse sand with a hygroscopic coefficient of 0.5 to a 

 clay loam with a value of 13.2. Their data, however, were not presented 

 in such form as to show the concordance of the hygroscopic coefficients 

 calculated from the moisture equivalents with those directly deter- 

 mined, and for this reason we consider it desirable to so present them 

 (Table I). 



Table I. — Relation of the moisture equivalent to the hygroscopic coefficient shown by data 



of Briggs and Shantz l 



1 Derived from Briggs and Shantz (7, p. 57, 60, 65, Tables XVII, XIX, and XX). 



2 Omitting 7 and 2. 



Excepting the two sands, i and 2, the ratio varies from 3. 11 to 2.22, a 

 range of 40 per cent, reaching a maximum in the case of a sandy loam 

 with a hygroscopic coefficient of 6.3 and a minimum in a clay loam with 

 the coefficient 13.2. In the case of the latter the value calculated from 

 the mean ratio, 2.71, differs by 2.4 from that obtained by direct determi- 

 nation. Two of the four clay-loam samples give concordant and two 

 rather discordant results, the divergence in the case of the latter being 

 similar to that obtained from the mechanical analysis of many of the 

 loess soils (3, p. 411). 



