4i6 



Journal of Agricultural Research 



Vol. X, No. 8 



RELATION OF RATE OE PENETRATION TO THE HYGROSCOPICITY 



The distance of penetration shows surprisingly little dependence upon 

 the texture as expressed by either the hygroscopic coefficient or the 

 moisture equivalent (Table XV). Thus, soils E, H, and M, with coeffi- 

 cients of lo.i, 7.6, and 3.3, respectively, in Experiments II and III show 

 a penetration almost identical both at the end of 24 hours and at the 

 end of 5 days, and in Experiment I the differences are very slight (Table 

 XVI). It was to be expected that the rate of movement would vary 

 inversely as the fineness of texture of the soils. The nearest approach 

 to such a relation is exhibited when the soils are used in the driest form, 

 and at the end of the fifth day it is more evident than during the first 

 24 hours. 



Table XV. — Distances to which l inch of "water had penetrated at the end of 24 hours 

 and 5 days, respectively, showing the relation to the hygroscopic coefficient and to the 

 moisture equivalent 



Soil. 



A 



B. 

 C. 

 D 

 E. 

 F. 

 G. 

 H 

 I. 



J- 

 K 

 L. 



M 

 N, 

 O. 

 P, 



Distance of penetration. 



At end of 24 hours. 



Experi- 

 ment 

 I. 



Inches 



3 ' 



4- 



4 



3 



4 



4 



4 



4 



4 



5 



4 



6, 



5 

 6 



" 3 

 6.7 



Experi- 

 ment 

 II. 



Inches. 

 6.2 



6.3 



6. I 



5-4 

 6.6 

 7.2 



6.5 

 6.6 

 6.2 

 6.7 

 6.8 



9-3 

 6.6 



Experi- 

 ment 

 III. 



Inches. 

 10. I 



8.6 



7-4 

 8.8 



7.8 



IO-3 



8.3 



"13.8 



8.7 



At end of s days. 



Experi- 

 ment 

 I. 



Inches. 



3-9 

 4.6 



4.8 

 4. 2 



5-0 

 5-0 

 5-6 

 5-6 



5-0 

 6.6 

 6.2 

 7.8 

 5-6 

 8.8 

 10.3 

 9.8 



Experi- 

 ment 

 II. 



Inches. 

 6.9 

 7.6 



7.0 



6.3 

 8.2 



8.7 



8.2 



8.3 



7-4 

 8.7 

 8.9 

 II. 7 

 7-5 



Experi- 

 ment 

 III. 



Inches. 

 II. 7 



IO-3 



8.9 



10. o 



10.3 



a At the bottom of the cylinders. 



Table XVI. — Lack of dependence of depth of penetration upon the texture when I inch of 

 water is applied, as illustrated by three dissimilar soils 



