PROPERTIES OF THE COLLOIDAL SOIL MATERIAL 
33 
The data which were obtained in this investigation of properties 
are brought together in Table 18 for convenience in reference. This 
table also includes some of the data given in previous publications 
(«,«5). 
Table 18. — Summary of properties of soil colloids 
Kind of colloid 
Specific 
gravity 
in water 
Average 
diam- 
eter of 
parti- 
cles 
Surface 
per gram 
of col- 
loid cal- 
culated 
Number of 
particles 
per gram 
of colloid 
calculated 
Heat of 
wetting 
per 
gram of 
colloid 
NH 2 ad- 
sorbed 
per 
gram of 
colloid 
H 2 
vapor 
adsorbed 
over 30 
per cent 
sulphuric 
acid per 
gram of 
colloid 
Im- 
bibed 
water 
Fallon loam soil 
2.766 
2.718 
2.627 
2.748 
Milli- 
crons 
102 
91 
106 
128 
111 
129 
141 
Square 
meters 
21.7 
24.7 
21.7 
17.0 
19.9 
17.1 
15.7 
680 by 1012 
9F0 by 1012 
613 by 1012 
335 by 1012 
505 by 1012 
322 by 10i2 
263 by 1012 
Calories 
17.5 
16.3 
14.6 
9.8 
8.3 
7.6 
5.3 
8.0 
4.5 
7.2 
7.9 
11.8 
16.3 
17.6 
Gram 
0. 0532 
.0529 
.0415 
.0264 
.0214 
.0266 
.0177 
~~.~0192~ 
.0293 
.0299 
.0358 
.0617 
.0614 
Gram 
0. 1776 
.1605 
.1305 
.1143 
.0633 
.0845 
.0518 
.0886 
Per 
cent 
139 
123 
Marshall loam soil 
101 
Sassafras silt loam subsoil .. 
Huntington loam soil 
76 
60 
Noifolk tne sandy loam 
subsoil. ... 
2.708 
63 
Susquehanna clay subsoil.. 
88 
Cecil clay loam subsoil 
48 
Hagerstown loam subsoil .. 

Miami silty clay loam 
84 
Wabash silt loam soil 
Kind of colloid 
Mois- 
ture 
equiv- 
alent 
Volume 
in- 
crease 
in 
water 
Volume 
of floe 
per 
gram 
of col- 
loid 
Viscos- 
ity of 2 
per cent 
sols 
Concen- 
tration 
required 
to give a 
viscosity 
of 1.9 
Methy- 
lene blue 
required 
to render 
1 gram of 
colloid 
isoelectric 
Ex- 
change- 
able 
Ca+Mg 
+K+Na 
per gram 
of colloid 
pH 
Malachite 
green ad- 
sorbed 
per gram 
of colloid 
Fallon loam soil 
Per 
cent 
120 
94 
72 
62 
64 
62 
67 
Per 
cent 
150 
90 
64 
64 
46 
38 
82 
46 
Cubic 
centi- 
meters 
128 
110 
58.5 
38.0 
31.5 
31.0 
31.0 
1.33 
1.14 
1.23 
1.33 
1.16 
1.12 
1.27 
Per cent 
by weight 
11.2 
13.8 
13.8 
13.1 
19.0 
16.4 
11.9 
Gram 
0.287 
.253 
.200 
.082 
.100 
.057 
Milli- 
equiva- 
lents 
1.080 
.687 
.528 
.227 
8.2 
6.9 
7.1 
5.7 
7.0 
5.3 
5.6 
Gram 
Sharkey clay soil 
Marshall loam soil 
Sassafras silt loam sub- 
soil.. 
Huntington loam soil.. 
Norfolk fine sandy 
loam subsoil 
.091 
Susquehanna clay sub- 
soil 
.055 .087 
i 
Cecil clay loam sub- 
soil 
0. 1582 
Chester loam soil 
.1348 
Hagerstown loam sub- 
soil .. 
.1704 
Miami silty clay loam 
subsoil... 
64 
.2096 
Stockton clay adobe 
soil 
.4128 
Wabash silt loam soil.. 
.3698 
Although the data in Table 18 are not sufficient to bring out all 
differences in the properties of the various colloids, they are suffi- 
cient to show that significant relationships exist between the proper- 
ties. Some degree of relationship between the properties discussed 
in the preceding pages is to be expected, since these properties doubt- 
