312 G. W. Grab/mm.— Wells of Worth-Eastern Sudan. 



relating to the normal flow, but they show that even in its rapid 

 passage a flood can pick up a considerable quantity of salts. During 

 the flood the flow in the Valley Fill is in a direction away from the 

 stream-bed, so that it does not appear possible that the salts could be 

 derived through admixture with the normal underflow. Their 

 presence can, however, be explained by the solution of the accumulation 

 of salts formed on the surface of the ground through the evaporation 



SUDAir 



Fig. 2. Map of the vicinity of Port Sudan, showing the position of the kicalities to 

 which the water analyses (on p. 318) rekte. 



of water raised by capillary action. This would also account for the 

 resemblance that the proportions of the different constituents bear to 

 one another in flood and normal flow. If such is the case, the quantities 

 of salts should vary in a succession of floods, the later ones containing 

 much less than the first, but figures are not available to test this. 



Analysis YI shows the composition of a sample taken from a well 

 at a distance of about 400 yards from the stream-bed, a little way 



