Investigations Begarding Brack'' (Alkali) in Cape Colony Soils. 143 
In the sample of water from the pit at Thebus the white alkaU was 
well within the limits of safety, but the black alkali was on the border- 
line, and in the sample of water from the dam the limit was apparently 
exceeded, although the smallness of the sample sent prevented this being 
definitely ascertained. 
It must, of course, be kept in view that the figures with which the 
analytical results of the Thebus water are compared are derived from 
experimental data obtained in Europe and America. If the facilities for 
making such very necessary experiments existed here, figures obtained 
under local conditions might be found to differ from those obtained in 
Europe and in the United States, but this very fact makes it all the more 
necessary to exercise great caution in proceeding with extensive irrigation 
schemes. 
Division of Eobertson. 
A series of determinations, similar to those conducted in regard to the 
Thebus soils, have also been made in connection with the soil of the 
Government Experiment Station at Eobertson. Two soils were collected 
for this purpose on the station. The soil at one part of the farm was a 
red sandy loam with a clayey subsoil and tending towards brackness 
in parts. From one of these brack patches the samples marked S were 
taken. A calcareous loam, in another part of the farm, showed brack 
EOBEKTSON SOILS. 
1 
Number. 
Sodium 
Chloride. 
Sodium 
Sulphate. 
Sodium 
Carbonate. 
Total Alkaline 
Salts. 
Calcium 
Sulphate. 
Calcium 
Carbonate. 
Magnesium 
Sulphate. 
Magnesium 
Carbonate. 
Total S 
Sal 
id 
)oluble 
ts. 
'6 
o 
% 
% 
% 
% 
% 
% 
% 
% 
% 
% 
El 
•024 
•060 
E2 
•018 
•044 
E3 
•010 
•070 
E4 
•Oil 
•062 
E5 
'Oil 
•056 
E6 
•019 
•080 
SI 
1-029 
•162 
1^191 
•112 
•020 
•043 
1-366 
1^400 
S2 
•942 
•114 
1^056 
•088 
•020 
•071 
1-235 
1^272 
S3 
•662 
•037 
•699 
•037 
•067 
•003 
•806 
•858 
S4 
•516 
•071 
•587 
•029 
•041 
•018 
•675 
•700 
S5 
•487 
•082 
•569 
•024 
•014 
•027 
•634 
•674 
S6 
•409 
•082 
•491 
•018 
•014 
•030 
•553 
•572 
S7 
•342 
•062 
•404 
•016 
•014 
•005 
439 
•504 
S8 
•301 
•067 
•368 
•014 
•007 
•005 
•394 
•450 
S9 
•291 
•066 
•357 
•009 
•012 
•Oil 
•389 
•428 
SIO 
•307 
•073 
•380 
•012 
•012 
•404 
•476 
Sll 
•321 
•076 
•397 
.007 
•012 
•004 
•420 
•496 
(The blanks in the upper part of this table signify " undetermined.") 
