JMtNAl OF AfMILTIM RESEARCH 
DEPARTMENT OF AGRICULTURE 
Vol. VII Washington, D. C., November 20, 1916 No. 8 
USE OF TWO INDIRECT METHODS FOR THE DETERMI¬ 
NATION OF THE HYGROSCOPIC COEFFICIENTS OF 
SOILS 1 
By Frederick J. Alway, Chief, Division of Soils , Agricultural Experiment Station, 
University of Minnesota, and Verne L. Clark, formerly Assistant in Chemistry, 
Nebraska Agricultural Experiment Station 
INTRODUCTION 
The relative advantages and disadvantages of the moisture-equivalent 
method for the indirect determination of the hygroscopic coefficients of 
soils have been discussed in a previous article G). 2 While in connection 
with soil-survey reports the moisture equivalents may conveniently be 
used to indicate the relative fineness of texture as a single-valued expres¬ 
sion, 3 even the determination of these consumes far more time than is 
desirable in connection with many soil studies. 
A very simple, rapid method seemed to be offered by a formula derived 
by Briggs and Shantz (4, p. 66) for the estimation of the hygroscopic 
coefficient from the maximum water capacity, as determined by Hil- 
gard’s method. Such an indirect method would prove extremely useful 
if it could be relied upon to give results in at least fair accord with those 
obtained by direct determination. The determination of the maximum 
water capacity by Hilgard’s method requires only very simple apparatus, 
consumes but little time, and can be carried out in the most poorly 
equipped laboratory and doubtless even in an ordinary farm kitchen 
(14). To test the reliability of this proposed method, we have made 
determinations of the water capacity of 53 soils of which the hygroscopic 
coefficients had previously been carefully determined. 
1 The work reported in this paper was carried out in 1912 at the Nebraska Agricultural Experiment 
Station, where the authors were, respectively, Chemist and Assistant in Chemistry. 
3 Reference is made by number to “ Literature dted,” p. 359. 
* The advantages of such a single-valued expression of the “different degrees of ‘heaviness* * of soils” 
(7, p. 440) appears to have first been suggested by Hilgard in connection with his introduction of the deter¬ 
mination of the hygroscopic coefficient (6, p. xi). 
Journal of Agricultural Research, 
Dept, of Agriculture, Washington, D. C. 
* c .. 
(345) 
Vol. VII, No. 8 
Nov, 20, 1916 
Nebr.—1 
64312°—16 
