Oct. 22 , 1917 
Direct Determination, of the Hygroscopic Coefficient 
157 
In the case of one of the control soils, I, the values shown in Table V 
were obtained by 24 hours’ exposure at different temperatures. Another 
control soil, A, was used in both summer and winter. Higher values 
(Table VI) were found during the wanner weather. When any distinct 
change was caused by an elevation of the temperature, it appeared in all 
cases to be an increase rather than a decrease in the amount of moisture 
absorbed. This is in accordance with the conclusions of Hilgard and of 
I.iptnan and Sharp. 
Table V .—Influence of the temperature upon the amount of moisture absorbed by Soil I 
Date. 
Temperature. 
Hygroscopic coefficient. 
Maxi¬ 
mum. 
Mini¬ 
mum. 
Deter¬ 
mina¬ 
tion 1. 
Deter¬ 
mina¬ 
tion 2. 
Deter¬ 
mina¬ 
tion 3. ; 
Deter¬ 
mina¬ 
tion 4. 
Aver¬ 
age. 
Jan. 17-18. 
Feb. 27-28. 
Feb. 29-Mar. 1. 
•c. 
2I * 5 
16. 0 
14 - 5 
0 C. 
21 
*5 
12 
24. 0 
20. 7 
19. 7 
22. 3 
20. 4 
19. 6 
24. 7 
20. 2 
2 5 - 3 
■ 
24. 1 
20. 4 
19. 6 
Table VI .—Concordance of values found on successive days for the hygroscopic coefficients 
of control soils 
Date. 
Temperature 
of room. 
^Soil A. 
Soil B. 
Maxi¬ 
mum. 
[ 
Mini¬ 
mum. 
* Determination. 
Determination. 
1 
2 
Aver¬ 
age. 
1 
2 
Aver¬ 
age. 
0 C. 
e C. 
Jan. 22.. 
16 
15 
5-6 
6, 0 
5.8 
IO. 2 
10.0 
IO. I 
23 . 
16 
15 
5 * 9 
5-9 
5-9 
5 
10. 0 
IO. 2 
24. 
17 
17 
5 * 7 
5 * 7 
5 - 7 
10. 2 
10. 0 
10. 1 
25. 
18 
18 
5 - 5 
5 - 5 
5 * 5 
10. 4 
10. 0 
10. 2 
26.. 
J 9 
18 
5 - 5 
1 5-6 
5 - 5 
10. 0 
10. 0 
10. 0 
27. 
21 
16 
5- 6 
5-6 
5-6 
9. 9 
9.9 
9. 9 
28. 
21 
16 
e, 6 
r 8 
r *7 
TA O 
29. 
20 
16 
5-5 
j - 0 
5 - 5 
5 * 7 
5 - 5 
IU. Z 
10. 0 
10. 0 
IO. 2 
IO. 0 
Feb. 2 . 
20 
16 
5 * 5 
5- 6 
5 - 5 
IO. I 
10. 0 
10. 0 
4 . 
17 
5 - 9 
6. 1 
6. 0 
IO. 2 
10.4 
10. 3 
Average. 
r 7 
o- / 
1 1 
IO. I 
Soil A. 
Soil I. 
June 12. 
22 
22 
5-9 
5-4 
5* 6 
20. O 
20.1 
20. O 
13 .! 
22 
21 
5 - 7 
5-9 
5-8 
20. O 
20.0 
20 . O 
14.1 
23 
23 
6-3 
6. 1 
6. 2 
21. 6 
21. 6 
21. 6 
. 
23 
22 
6. 0 
6.4 
6. 2 
22. 9 
22. 3 
22. 6 
16. 
23 
22 
6. 2 
6- 3 
6. 2 
22 . O 
22. 5 
22. 2 
i 7 . 
23 
22 
6. 0 
6-3 
6. 1 
23. O 
23. 0 
23. O 
*9 . 
22 
22 
6. 0 
5-8 
5*9 
22. O 
22. 1 
22. O 
20. 
23 
22 
6. 2 . 
6. 1 
6. 1 
20. 4 
20. 9 
20. 5 
21. 
23 
22 
6. 4 
6. 4 
22. 6 
22 . Q 
22. 2 
23. 
23 
23 
6. 4 
6.4 
21. 4 
20. O 
20. 7 
Average . 
6. 1 
At P* 
i 
3 
.1. 
21. 5 
