144 
Tra7isactions of the Boyal Society of South Africa. 
water a short distance from the surface. Under these circumstances 
fuller investigations into the alkaline character of the soil were made. 
At two spots, E and S, the samples mentioned below were collected 
representing successive sections of the soil to a total depth of 4 feet ; at 
E, six samples, each extending vertically through 8 inches, were taken ; 
at S, an alkaline patch with a superficial area of about 2,000 square yards, 
eleven samples were taken, of which the first eight represented 3-inch, 
and the remaining three 8-inch vertical sections. 
The analyses made resulted as shown in Table on previous page. 
In the case of the soil E there was no necessity to push the investiga- 
tion further, the total soluble salts being considerably below the danger 
limit. At S a very different condition of things exists, and a diagram is 
attached, showing the curves of the various soluble salts in the soil as we 
descend from the surface to a depth of 4 feet. 
Division of Carnaevon. 
An investigation of the alkaline tracts near the large dam called Van 
Wyks Vlei, 45 miles north-west of Carnarvon village, was conducted, on 
lines somewhat similar to those already indicated. By means of this dam, 
which holds many thousand million gallons of water, fairly extensive 
irrigation has been practised for several years. Under this treatment the 
barren area has gradually spread, and at present the nearest land that is 
being cultivated below the dam is no less than 7 miles distant therefrom. 
It is, nevertheless, estimated that about 20,000 acres of irrigable land of 
good quality are still free from any signs of alkalinity, and available for 
cultivation. 
Two samples of water from artesian borings in the vicinity of the dam 
were analysed, with the following results, stated in grains per gallon : — 
No. 1. No. 2. 
Sodium chloride 48-94 358-98 
Magnesium sulphate 49-20 177'57 
Calcium sulphate 53-26 76'86 
Calcium carbonate 10-16 147*95 
A specimen of water from the dam itself was found to contain chlorine 
— in combination as chlorides — to the amount of 1154-6 grains per gallon, 
and, on another occasion, a sample similarly taken yielded the following 
figures : — 
Sodium chloride 862-9 grains per gallon 
Sodium sulphate 226*3 ,, ,, ,, 
At some places in the neighbourhood beds of limestone, containing 
gypsum occur : specimens of these were analysed, but did not prove of 
good quality. 
