36 
Journal of Agricultural Research 
VoL IX, No. a 
In the latter group, exposed a year before, equilibrium had not been 
attained when the cylinders had been opened after periods of 31, 44, and 
54 days, respectively, and the moisture content increased with the depth; 
while in the latter experiment, with a considerably longer exposure, the . 
water was quite uniformly distributed throughout the 30 inches, varying 
only between 13.5 and 14.0, except in the first 2-inch section, in which 
it averaged 14.5 per cent. 
The final average of the moisture content of the four cylinders of the later 
group (No. IV to VII) was 13.8, between 2.4 and 2.5 times the hygroscopic 
coefficient and approximately the same as the moisture equivalent, 13.5. 
Table IV. —Ratio of moisture content to hygroscopic coefficient in soil J t entirely pro¬ 
tected from evaporation and separated from the earth 1 s soil mass by a 6-inch layer of 
coarse quartz sand or gravel. To the cylinders , filled with approximately 50 pounds of 
air-dried soil , there was added 1 5 pounds of water , after which the cylinders were left 126 
days 
Depth of section. 
With sand. 
With gravel. 
Average, 
I-IV. 
Cylinder I. 
Cylinder II. 
Cylinder III. 
Cylinder IV. 
Inches. 
Per cent. 
Per cent. 
Per cent. 
Per cent. 
Per cent . 
3-7 
3*4 
3*4 
3*3 
3*4 
3-5 
3*2 
3*2 
3*o 
3*2 
3-4 
3* 1 
3*2 
3*o 
3*2 
3-4 
3* 1 
3*2 
3*o 
3*2 
5. 
3*5 
3*2 
3*o 
2.9 
3* 1 
3*5 
3*2 
3*2 
3*o 
3*2 
7 .. 
3*5 
3*2 
3*3 
3* 1 
3*3 
3*6 
3*2 
3*3 
3*2 
3*3 
9.•*• 
3*7 
3*3 
3*4 
3* 1 
3*4 
10 . 
3*7 
3*3 
3*4 
3* 1 
3*4 
11 . 
3* 7 
3*3 
3*4 
3*2 
3*4 
3*7 
3*4 
3*5 
3*2 
3*4 
13 . 
3* 8 
3*4 
3*5 
3*2 
3* 5 
14 . 
3* 8 
3*5 
3*6 
3*3 
3*5 
15 . 
3*9 
3*5 
3*6 
3*3 
3*6 
3*9 
3*6 
3*7 
3*4 
3*6 
17 . 
4 . 1 
3*6 
3*7 
3*5 
3*7 
18 . 
4.0 
3*7 
3* 8 
3*4 
3*7 
19 . 
4 . 1 
3*7 
3*9 
3*5 
3* 8 
4- 1 
3* 8 
3*9 
3*5 
3* 8 
4.2 
3* 8 
3*9 
3*6 
3*9 
4-3 
3*9 
3*9 
3*6 
3*9 
23 . 
4-5 
3*9 
4.1 
3*6 
4.0 
24 . 
4 . 6 
4*o 
4* 1 
* 3*7 
4 . 1 
25 . 
4 . 8 
4.1 
4.2 
3*7 
4.2 
4.9 
4.2 
4.2 
3*7 
4-3 
27.. 
4.9 
4*2 
4*3 
3* 8 
4-3 
5*4 
4*5 
4 . 0 
3*9 
4 . 6 
Average. 
4.0 
3*6 
3*7 
3*3 
3 * <5 
B.— With a loam interrupted by a gravel or sand layer. —To 
determine the effect of an interrupting layer of coarse material, sand or 
gravel, four similar cylinders were filled with the same soil, J, but on the 
loess at the bottom of each cylinder there was first placed a 6-inch layer of 
quartz sand in the case of Cylinders I and II; and of gravel in III and 
IV. These coarse materials were tamped in uniformly, after which the 
