404 The Philippine Journal of Science 1921 
subsoil contains a larger percentage of clay than does the top- 
soil. Little sand or coarser material was present in any of the 
samples. The soil in the Bang Bakok orchard is slightly coarser 
than that of the Nakorn Chaisri orchard. 
Since the irrigation water used at Ban Mai is extremely 
salty, it would be expected that the orchard soil would also 
contain a large percentage of salt. In order to prove this point 
the soils of the various types from the Ban Mai region and, for 
comparison, those from the Bang Bakok district, where the 
water used for irrigation according to the analysis is not salty 
at that time of the year, were analyzed for their salt content. 
The following samples were analyzed from an orchard at Ban 
Mai : No. 1, topsoil; No. 2, subsoil; and No. 3, canal mud, obtained 
from the bottom of a canal leading from Tachin River to the * 
orchard. The samples of soil analyzed from Bang Bakok, near 
Bangkok were from the following locations: No. 4, topsoil in 
an orchard ; No. 5, canal mud from a canal in the orchard, lead- 
ing from the Menam Chao Phaya. The soils were heated in an 
oven until weight was constant. Five-gram samples were taken, 
in triplicate. These samples were treated with water at 60° C. 
for three days, and the extract was then tested for chlorine 
by the silver nitrate titration method. Table 12 gives the results 
of the determinations. The parts per million of chlorine were 
determined from the water-soluble extract of the soils. From 
this was computed the percentage of sodium chloride present 
in the soils. 
Table 12. — Analysis of the water-soluble extract of soils in pummelo 
orchards at Ban Mai and at Bang Bakok, Siam.’ 1 
Sam- 
ple. 
Date. 
Total 
chlorine. 
Sodium 
chloride. 
Location. 
1 
June 7, 1920 
Parte per 
million. 
6,160 
Per cent. 
1.006 
Topsoil, Ban Mai. 
2 
Do 
6, 100 
0.8 
Subsoil, Ban Mai. 
3 
Do 
16, 100 
2.6 
Canal mud. Ban Mai. 
4 
June 14, 1920 
1,100 
0. 18 
Topsoil, Bang Bakok. 
6 
Do 
2,200 
0.83 
Canal mud, Bang Bakok. 
a Determinations by Miss H. Kenward, of the department of chemistry. College of 
Agriculture, Los Banos. 
The results given in Table 12 show that the topsoil, subsoil, 
and canal mud from Ban Mai were, all, extremely high in salt 
content. This is what would be expected, as the water used 
for irrigation was at that time very salty, as indicated in Table 
