18 
BULLETIN 1193. U. S. DEPARTMENT OF AGRICULTURE. 
capacity of each fraction of colloidal material for dye, water, and 
ammonia is given in columns 3 to 5, and in columns 7 to 9 the rela- 
tive adsorptive capacities of the different fractions are given, the 
adsorptive capacity of the first fraction extracted being expressed 
as 100 in each case. 
Table 3. — Adsorptive capacities of colloidal materials successive!)/ extracted from the 
same soil. 
Colloidal material. 
Quan- 
tity of 
colloidal 
mate- 
rial ex- 
tracted, 
in per- 
cent,— 
of 
whole 
soil. 
Adsorption per gram of 
colloidal material. 
Quan- 
tity of 
colloidal 
mate- 
rial in 
per- 
centage 
of all 
colloidal 
mate- 
rial iso- 
lated. 
Relative adsorp- 
tive capacities of 
different fractions 
of colloidal 
material for— 
Dye. 
H 2 0. 
NH 3 . 
Dye. 
H 2 0. 
100 
89 
68 
40 
NH 3 . 
Huntington loam, subsoil: 
First fraction of colloid 
Per ct. 
2.10 
6.06 
2.12 
.33 
Gram. 
0. 1437 
.1174 
. 0998 
.0477 
Gram. 
0. 2998 
.2679 
.2049 
.1194 
Gram. 
0. 0324 
.0301 
. 0235 
.0144 
rcr ct. 
19.8 
57.1 
20.0 
3.1 
100 
82 
69 
33 
100 
93 
Third fraction of colloid 
73 
44 
Total quantity colloid extracted 
10.61 
.1169 
. 2570 
.0287 
100 
81 
86 
89 
Marshall silt loam, soil: 
First fraction of colloid 
.64 
4.50 
.97 
.90 
.3159 
. 3035 
.2906 
.1916 
.3090 
. 2951 
.2902 
.2328 
©coo 
9.1 
64.2 
13.8 
12.8 
100 
96 
92 
61 
100 
96 
94 
100 
Second fraction of colloid 
95 
Third fraction of colloid 
98 
Fourth fraction of colloid 
75 1 91 
Total quantity colloid extracted 
7.01 
. 2885 
.2877 
. 0581 
100 
91 
93 i 95 
Sassafras silt loam, subsoil: 
.88 
3.05 
1.76 
.50 
. 2058 
. 1778 
.2079 
.2121 
. 3388 
.3053 
.3006 
.2719 
.0387 
.0406 
.0412 
.0388 
14.2 
49.3 
28.4 
8.1 
100 
86 
101 
103 
100 100 
90 
105 
89 
80 
106 
Fourth fraction of colloid 
100 
Total quantity colloid extracted 
6.19 
.1931 
.3060 
.0404 
100 
94 
90 
104 
Sharkey clay, soil: 
12.1 
11.9 
12.3 
2.2 
.4044 
. 3995 
. 5043 
.3576 
. 3237 
.3271 
.2646 
.3211 
.0609 
. 0572 
.0460 
. 0553 
31.4 
30.9 
32.0 
5.7 
100 
99 
125 
88 
1 
100 ' 100 
101 94 
82 , 76 
99 i 91 
Total quantity colloid extracted 
38.5 
.4321 
.3057 
.0547 
100 
107 
94 J 90 
Vega Baja clay loam, sou: 
First fraction of colloid 
16.6 
12.7 
1.1 
.0584 
.0463 
.0494 
.3125 
.2749 
.3298 
.0206 
. 0165 
.0182 
54.6 
41.7 
3.6 
100 
79 
85 
100 
88 
106 
100 
80 
Third fraction of colloid 
88 
Total quantity colloid extracted 
30.4 
.0530 
.2974 
.0188 
100 
91 
95 | 91 
On the whole, the different colloidal fractions isolated from the 
same soil were very similar in adsorptive capacity to the first sample 
extracted. In only two or three cases did any of the fractions differ 
from the first fraction by more than 25 per cent. In the case of the 
Marshall soil and the Huntington subsoil there was a gradual decrease 
in the adsorptive capacities of the lots of colloid successively extracted; 
but this does not hold for the other three soils. Chemical analyses 
made of the different colloidal fractions also showed that there was 
no marked variation between the first two or three fractions in 
ultimate chemical composition. The content of iron, aluminum, and 
silica was very constant in all fractions except the last; this in some 
cases was higher in silica and lower in iron and alumina than the 
