SALTNESS OF THE SEA. 15 



impregnated with salt that the body of a man floats on its surface 

 without sinking, like a piece of cork upon fresh water. The supposed 

 causes are excessive evaporation and the absence of rivers of any 

 importance. 



The saltness of the sea seems to be generally less towards the 

 poles than the equator ; but there are exceptions to this law. In 

 the Irish Channel, near the Cumberland coast, the water contains 

 salt equal to the fortieth of its weight ; on the coast of France it is 

 equal to one thirty-second ; in the Baltic it is equal to a thirtieth ; 

 at Teneriffe a twenty-eighth; and off the coast of Spain to a 

 sixteenth. Again, in many places the sea is less salt at the surface 

 than at the bottom. In the Straits of the Dardanelles at Constan- 

 tinople the proportion is as seventy-two to sixty-two ; in the Medi- 

 terranean it is as thirty-two to twenty-nine. It is also stated that as 

 the salt increases at a certain depth the water becomes less bitter. 

 At the mouths of the great rivers, it is scarcely necessary to add, 

 the water is always less saline than on shores which receive no 

 supplies of fresh water ; the same remark applies to sea water in the 

 vicinity of polar ice, the melting of which is productive of much 

 fresh water. A recent analysis of the water of the Dead Sea by 

 M. Roux gives about two pounds of salt to one gallon of water ; 

 no mineral water, if we except that of the Salt Lake of Utah, is so 

 largely impregnated with saline substances ; the quantity of bromide 

 of magnesia is 0*35 grammes to the litre. The water of the Dead 

 Sea is, according to these proportions, a rich natural depository of 

 bromide, which it might be made to furnish abundantly. The waters 

 of the great Lake of Utah and Lake Ourmiah in Persia are both 

 highly saline. In Lake Ourmiah, as in the Dead Sea, the proportion 

 of salt is six times greater than in the ocean. Many of our fresh- 

 water lakes were probably salt originally, but have by degrees lost 

 their saline properties by the mingling of their waters with those of 

 the rivers which traverse or flow into them. Among the lakes which 

 appear to have been divested of their saline properties may be 

 mentioned the great lakes of Canada and the Sea of Baikal, in all of 

 which seals and other marine animals are still found, which have 

 become acclimatised as the water gradually became fresh. 



The saltness of sea water increases its density, and at the same 

 time its buoyancy, thus adapting it for bearing ships and other 

 burdens on its bosom ; moreover, to abbreviate slightly Dr. Maury's 

 remark, " the brine of the ocean is the ley of the earth." From it 

 the sea derives dynamical power, and its currents their main strength. 

 It is the salt of the sea that imparts to its waters those curious 



