Physical Geography of Hindostan. 347 



poured in. The Dead Sea, before attaining this condition of re- 

 pose, has sunk thirteen hundred feet below the Mediterranean, 

 the Caspian about one-fourth of this. Lakes originally salt, and 

 which to all appearance are no more than fragments severed 

 from the sea by the earthquake or volcano, and which have no 

 river or rain supplies whatever, in process of time dry up and 

 leave a mass of rock salt in their former basin. Such is the 

 formation in progress in the Lake Assal, in north-eastern 

 Africa, nearly five hundred feet below the level of the sea, 

 its waters having been this much depressed by evapora- 

 tion, having now almost altogether vanished, one mass of 

 salt remaining in their room. As it is clear in a case such 

 as that of the Mediterranean, that where salt water to a large 

 extent was poured in, and fresh water only was drawn off, a 

 constant concentration of brine must occur, the proposition 

 was laid down by the most distinguished of our geologists, 

 and long held unquestionable, that huge accumulations of 

 salt, in mass larger than all that Cheshire contains, were 

 being formed in its depths. The doctrine, eminently impro- 

 bable in itself, is now met by the discovery of an outward 

 under current, in all likelihood of brine. It is matter of 

 easy demonstration, that without some such arrangement as 

 this, the Red Sea must long ere now have been converted in- 

 to one mass of salt, its upper waters at all events being 

 known in reality to differ at present but little in saltness 

 from those of the Southern Ocean. The Red Sea forms an 

 excellent illustration of all kindred cases. Here we have 

 salt water flowing in perpetually through the Straits of 

 Babelmandeb to furnish supplies for a mass of vapour calcu- 

 lated, were the strait shut up, to lower the whole surface of 

 the sea eight feet annually, — and even with the open strait, 

 to add to its contents a proportionate quantity of salt. But 

 an under-current of brine, which, from its gravity, seeks the 

 bottom, flows out again to mingle with the waters of the 

 great Arabian Sea, where, swept along by currents, and 

 raised to the surface by tides and shoals, it is mingled by the 

 waves through the other waters which yearly receiving the 

 enormous monsoon torrents the Concan and the Ghauts supply, 

 become diluted to the proper strength of sea water, and 

 rendered uniform in their constitution, by the agitation of 



