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vi Transactions of the Boyal Society of South Africa. 
and sulphate of sodium, the first doing the most and the last the least 
injury. Natural drainage usually carried these noxious salts seawards, 
but this was prevented by (1) an impermeable layer below the surface 
forming a basin ; (2) compactness of the soil itself ; and (3) a high water- 
line in the subsoil. Even these obstacles, where frequent rain resulted in 
an even distribution of salts throughout the soil, were not always sufficient 
to prevent successful cultivation. The difficulty arose with a scanty rain- 
fall and a warm climate, or long drought after heavy rain ; then it became 
important to ascertain how much salt the soil could contain and still be 
successfully cultivated. 
Investigations had been made in the divisions of Herbert, Colesberg, 
Britstown, Steynsburg, Kobertson, and Carnarvon. In the first two cases 
only the soils at the surface were examined. The Britstown soils increased 
steadily in brak from the surface down to 6 feet ; the low rainfall did not 
permit of moisture penetrating to any depth and bringing up salts from 
below, but irrigation might alter this. Sodium carbonate was, however, 
practically absent. At Steynsburg a series of excavations, made over an 
area extending across 2 miles, showed large quantities of brak in the 
subsoil. The conditions grew worse as one proceeded down the valley, 
and only one of the soils fell within safe limits. The most abundant salt 
was sodium chloride, then came sodium sulphate, and in some cases 
sodium carbonate (black brak) was present, the soluble salts being distri- 
buted very irregularly through the soil. The effect of irrigation and culti- 
vation w^as shown in connection with a soil from a brak patch on the 
Government Experiment Station at Eobertson. Here analysis showed 
the greatest amount of salt at the surface, and a considerable diminution 
downwards. Near Van Wijk's Vlei both types of curve were illustrated. 
One soil, continuously cultivated for seventeen years, showed over 2-|- per 
cent, of soluble salts at the surface, diminishing to less than one-fourth 
that amount at a depth of 6 feet. A virgin soil from the same place 
showed only 0*2 per cent, at the surface, but on penetrating the soil this 
amount increased fivefold at the first foot. The former of the two soils 
had ceased to be capable of bearing crops — a fact explained by the existence 
of large quantities of sodium and calcium chlorides in the surface soil. 
Oedinaey Monthly Meeting. 
July 15, 1908. 
Mr. S. S. Hough, President, in the Chair. 
Messrs. E. P. Phillips, A. H. Kirkman, E. L. Calveeley, J. G. 
EosE, and H. Lotz were elected members of the Society. 
