Oct. 16, 1916 
Acidity and Adsorption in Soils 
125 
EXPERIMENTAL WORK 
MATERIALS USED 
Before taking up the detailed discussion of the data it appears desirable 
to describe briefly the materials used. Table I contains a list and 
description of all the soils referred to in this paper. 
Table) I .—Description of soils used in experimentation 
Laboratory No. 
Source of soil. 
General type. 
California. 
Silty clay loam. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
Fine-sandy loam. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
.do. 
Sandy loam. 
.do. 
Gravelly loam. 
.do. 
Clay adobe. 
.....do. 
Fine sandy loam. 
Wisconsin. 
Silty clay loam. 
.....do. 
Sandy loam. 
Pennsylvania. 
Silty loam. 
California. 
Fine sandy loam. 
Louisiana... 
Silty loam. 
California. 
Peat. 
Wisconsin. 
.do. 
California. 
Sandy loam. 
.do. 
Fine sandy loam. 
1 
1 
2 
3 
4 - 
5 
6 
7 
8 , 
9 
10. 
11 
12 
13 
14. 
15 
16 
17 
18 
19 
20, 
21 
22 
23 
24 - 
Remarks. 
Alkali soil. 
Very infertile. 
Alkali soil. 
Do. 
HYDROGEN-ION CONCENTRATION OF SOIL SUSPENSIONS 
Table II gives the amounts of soil and water used for making the 
suspensions. The soils were air-dried and passed through a i-mm. sieve. 
The H-ion concentration is expressed in the customary units of gram 
molecules of H ion per liter. 
In accordance with our preliminary statements, Table II gives evi¬ 
dence that soils may give rise to acid solutions—that is, solutions con¬ 
taining a preponderance of H ions over OH ions. This conception is in 
agreement with the conclusions which Truog (33) drew from his zinc- 
sulphid method. The work of Gillespie (13), paralleled by that pre¬ 
sented in Table II, conclusively proves that there may be an excess of H 
ions in the solution bathing the soil particles. 
Out of 22 soils examined by Gillespie (13), 17 were found to yield 
acid solutions. The writers experimented with 9 add soils. The soils 
were of widely different types and origin. These facts do not support 
