206 
Journal of Agricultural Research 
Vol. VIII, No. 6 
become inactive or unfree, to lose its solvent action, and to be removed 
from the field of action so far as the freezing-point lowering is concerned, 
and that the process of freezing changed the physical condition of the 
soil whereby some of this inactive or unfree water was liberated and 
went to dilute the original soil solution and thus decreased the lowering 
of the freezing point. 
In order to ascertain whether this hypothesis was correct, the effect 
of successive freezings upon the amount of water that would freeze in 
soils was studied in the dilatometer. The procedure consisted of re¬ 
freezing the same sample of soil in the dilatometer as was employed in 
the previous study. After the data of the first freezing were obtained, 
the dilatometer was taken out of the bath, its contents thawed, and the 
process of freezing was repeated a second time. Numerous trials showed 
that in the majority of cases equilibrium was attained in the second 
freezing—that is, very little, if any, more water froze after the second 
freezing. Many trials also showed that not very much more water 
would freeze if the soil was maintained at a temperature of —12° C. 
for one hour after the -first freezing, than by supercooling it to 3 0 at a 
temperature of — 4°, as followed in the regular procedure. In all the 
determinations made in this study, therefore, the soil was refrozen a 
second time in the same manner as in the first—that is, supercooled to 
3 0 in a cooling mixture of — 4 0 . The data obtained are detailed in 
Table V. The amount of water that fails to freeze in the first and 
second freezings is expressed both in cubic centimeters and in percentage 
of the 5 c. c. of water added to 25 gm. of soil. The difference in the 
percentage of water that fails to freeze in the first and second freezings 
indicates the effect of successive freezings upon the amount of water 
that becomes free. 
Table V .—Effect of successive freezings upon the amount of water that fails to freeze when 
5 c.c. are added to various soils 
Freezing period. 
Water 
in 
quartz 
sand 
failing 
to freeze. 
Water 
in sand 
failing 
to freeze. 
Water in sandy 
loam failing to 
freeze. 
Water 
in silt 
loam 
failing 
to freeze. 
Water 
in Car¬ 
rington 
loam 
failing 
tofreeze. 
Water in heavy 
silt loam failing 
to freeze. 
Water 
in su¬ 
perior 
clay 
failing 
to freeze. 
First 
test. 
Second 
test. 
First 
test. 
Second 
test. 
C.c. 
% 
C.c. 
% 
C.c. 
% 
C.c. 
% 
C.c. 
% 
C.c. 
% 
C.c. 
% 
C.c. 
% 
C.c. 
% 
First. 
0.1 
2.0 
0.3 
6.0 
0.8 
16.0 
i-is 
23.0 
2.00 
40.0 
2.80 
56.0 
3 * 7 ° 
74 -o 
3-501 
70.0 
3-50 
70.0 
Second. 
. 1 
2.0 
*3 
6.0 
.8 
16.0 
i-15 
23.0 
1.65 
33-0 
2.20 
44.0 
2. 75 
55-0 
3 - °5 
61.0 
3-oo 
60.0 
Difference. 
.0 
.0 
.0 
.0 
*° 
.0 
.0 
.0 
•35 
7.0 
.60 
I2> O 
•95 
19.0 
•45 
9.0 
• 5 ° : 
10.0 
