42 SALINE WATERS. 



It will thus be seen that the existence of brackish 

 waters in a district may at any time become a matter 

 of serious moment, in case of any prolonged drought 

 setting in. 



Why the waters should turn salt in this way is a 

 question more easily asked than answered ; but we may 

 be sure that it depends, like everything in Nature, 

 upon some plain and constant rule, could we only discover 

 it; and if we might venture to hazard an opinion upon 

 a matter concerning which there are so few data to 

 go upon, we should say that the collection of salt is 

 caused by imperfect drainage. 



In these very flat countries the rivers and streams 

 have no proper watershed to convey the waters to the 

 sea. The consequence is, heavy rains are certain to 

 cause disastrous floods; as the inundations subside, the 

 floods of course retire to the lowest levels : this accounts 

 for the formation of the extensive shallow lagoons, and 

 marshes, which are generally characteristic of these 

 countries; but as the water always holds in solution 

 a certain proportion of earthy salts, these are in con- 

 sequence carried down to, and collected at these spots ; 

 and are of course precipitated there, when the water 

 dries up ; and by the constant repetition of this process, 

 year by year, for vast periods of geological time, these 

 lagoons and lowlands are at length turned into salt 

 marshes, and sometimes even into deposits of pure salt. 



This theory seems to be the more probable, inas- 

 much as we know that large bodies of water, which 

 have no outlet to the sea, are always salt of these 

 we may cite the Caspian Sea, and especially the Dead 

 Sea, as prominent examples. It is probable that the 

 saltness of the ocean itself is due to similar causes, 



