THE CHEMICAL COMPOSITION OF SOIL. COLLOIDS 
23 
Table 6. — Relation 
ratio, 
CaO + Na 2 
R2O3 
temperature, and coloi 
ratio, average annual precipitation, 
OOIX 

i 
o|9 
q 
1 
a 
3s 
l£ 
j Source and locality of colloidal matter 
CGltf 
11 
= 3 
si 
Color 
» 
olo 

6 
53 *3 
to 
a 
m 
O 
« 
1 
1 
8 
c 
> 
< 
< 
Inch ex 
°F. 
5 
Cecil clay loam, subsoil, Georgia 
1.20 
0.25 
49 
62 
Red. 
4 
Cecil clay loam, soil, Georgia 
1.34 
.30 
49 
62 
Do. 
42 
Vega Baja soil, Porto Rico 
1.34 
.39 
69 
77 
Yellowish red 
40 
Susquehanna clay, Mississippi 
1.35 
.18 
58 
65 
Brilliant red. 
6 
Chester loam, surface, Virginia 
1.54 
.13 
144 
155 
Brown. 
3 
Cecil clay loam, surface, Maryland 
1.55 
.23 
40 
53 
Red. 
27 
Norfolk fine sandy loam, surface, North 
Carolina. 
1.67 
.29 
1 50 
152 
Yellowish brown. 
32 
Orangeburg fine sandy loam, subsoil, 
Mississippi. 
1.71 
.32 
153 
163 
Red. 
21 
Manor loam, surface, Maryland 
1.74 
.58 
40 
54 
Yellowish brown. 
7 
Chester loam, surface, Maryland 
1.77 
.59 
143 
153 
Do. 
8 
Chester loam, subsoil, Maryland 
1.79 
.26 
143 
153 
Light reddish brown. 
22 
Manor loam, subsoil, Maryland 
1.81 
1.83 
.38 
.35 
40 
153 
54 
163 
Yellowish brown. 
31 
Orangeburg fine sandy loam, soil, Mis- 
Dark brownish red. 
28 
sissippi. 
Norfolk fine sandy loam, subsoil, North 
Carolina. 
1.84 
.25 
150 
152 
Yellow. 
33 
Sassafras silt loam, soil, Maryland 
1.85 
.57 
'41 
55 
Brown. 
17 
Huntington loam, soil, Maryland 
1.86 
.62 
135 
153 
Dark brown. 
18 
Huntington loam, subsoil, Maryland 
1.89 
.47 
135 
153 
Light reddish brown. 
34 
Sassafras silt loam, subsoil, Maryland 
1.89 
.45 
41 
55 
Reddish brown. 
15 
Hagerstown loam, subsoil, Maryland 
1.89 
.41 
40 
54 
Brownish red. 
14 
Hagerstown loam, surface, Maryland 
1.91 
.89 
40 
54 
Dark reddish brown. 
19 
Iredell clav, subsoil, North Carolina 
1.93 
.48 
52 
64 
Light yellowish brown. 
12 ! Dunkirk clay loam, surface, New York.. 
1.99 
.69 
140 
145 
Yellowish olive. 
30 Ontario loam, subsoil, New York 
2.08 
.86 
!34 
147 
Dark reddish brown. 
41 Susquehanna clay, deep subsoil, .Mary- 
land. 
10 '. C 1 arks ville silt loam, subsoil, Kentucky.. 
2.10 
.49 
141 
153 
Yellowish red. 
2.10 
.41 
149 
158 
Reddish brown. 
29 Ontario loam, surface, New York 
2.13 
.89 
34 
47 
Dark grayish brown. 
9 Clarksville silt loam, surface, Kentucky.. 
2.18 
.43 
149 
158 
Dark brown. 
11 Crowley silt loam, surface, Louisiana 
2.40 
.62 
155 
168 
Grayish brown. 
25 Miami silty clay loam, surface, Indiana.. 
2.50 
.75 
137 
150 
Do. 
2 ' Carrington loam, subsoil, Iowa. 
2.64 
.96 
32 
47 
Dark grayish brown. 
26 Miami silty clay loam, subsoil, Indiana.. 
2.66 
1.29 
137 
150 
Brown. 
37 Stockton clay adobe, surface, California .. 
2.72 
.91 
14 
60 
Dark gray. 
1 | Carrington loam, surface, Iowa. 
2.75 
1.11 
32 
47 
Black. 
23 Marshall silt loam, surface, Nebraska 
2.82 
.93 
130 
151 
Very dark grayish 
brown. 
Light yellowish brown. 
39 Stockton clay adobe, subsoil, California.. 
2.85 
1.36 
128 
162 
38 Stockton clay adobe, surface, California.. 
2.87 
1.56 
128 
162 
Grayish brown. 
24 Marshall silt loam, subsoil, Nebraska 
2.87 
.99 
130 
151 
Dark grayish brown. 
36 Sharkey clay, surface, Mississippi 
3.07 
.91 
154 
166 
Do. 
43 Wabash silt loam, surface, Nebraska 
3.16 
1.63 
34 
52 
Black. 
35 Sharkey clay, Mississippi 
3.23 
1.53 
154 
166 
Grayish brown. 
20 Lufkin clay, subsoil, Mississippi 
3.30 
1.22 
52 
64 
Cream. 
44 Wabash silt loam, subsoil, Nebraska 
3.33 
1.15 
34 
52 
Black. 
45 Yolo clay, surface, California 
3.43 
2.11 
120 
158 
Light yellowish brown . 
16 : Houston black clay, surface, Texas 
3.56 
3.60 
38 
65 
Gray. 
13 
Fallon loam, surface, Nevada 
3.82 
2.44 
5 
51 
Light gray. 
1 Rainfall and temperature data are not from exact locality where soil sample was taken but from nearest 
place with available records. 
It can be seen from columns 3 and -A of Table 6 that the A , ^ Tt-.' 2 ^ 
Al 2 3 +Fe 2 3 
ratios generally increase as the at r> ' lr — rr ratios increase, that is r 
the sum of the lime and soda in the colloidal matter follows the 
silica in a general way. A quantitative expression of the relation 
of the above ratios to one another is to be found in the coefficient 
of correlation (£?). The coefficient of correlation between these two 
