26 THE TANGANYIKA PROBLEM. 



suggests that some change in the sea must have taken place. 

 In consequence of this it is incumbent on us to inquire 

 whether there are other grounds for believing that the sea 

 has become and is becoming steadily more salt. 



Turning to this matter we find that the subject has 

 already been considered, but in general from other aspects 

 than that which immediately concerns us at the present 

 time. Thus, within the last few years we find both Jolly 

 and others considering the increase of salinity of the ocean, 

 and taking its existence for granted as a means in an 

 attempt to ascertain the age of the earth. That the saline 

 matters in the sea have changed in composition and in- 

 creased in amount seems, indeed, almost indisputable from 

 a variety of considerations. Thus Jolly points out that 

 numerous analyses of the rocks of different ages show a 

 marked contrast in the amount of common salt which they 

 contain, the older the rocks the more the salt, and, further, 

 that the percentage lost in the more recent deposits is 

 matched bv the amount of salt dissolved in the water of 

 the present sea. Jolly also comes to the conclusion, and 

 apparently with good reason, that the amount of salt which 

 has been again lost by the sea, in the formation of rock- 

 salt deposits, is to be considered as infinitesimal and 

 negligible. 



Indeed, the same results would be forced upon us, if we 

 were to apply the experience we have gained in the study 

 of fresh and salt water lakes to the study of the sea itself. 

 We find that where lakes have an outflow they remain 

 fresh, because the salt which is brought into them is 

 always being carried away by this outflow, but in lakes 

 which have no outflow the modicum of salt which the 

 rivers bring down remains in the water of the lake, so 

 that it becomes more and more saturated until finally the 



