14 THE OCEAN WORLD. 
Pure water is produced by a combination of one volume of 
oxygen and of two volumes of hydrogen, or in weight, 100 oxygen, 
12°50 hydrogen. Sea water is composed of the same ; but we find 
there, besides, other elements, the presence of which chemistry 
reveals to us. In 1,000 grains of sea water the following ingredients 
are found :— 
‘Water en 4. -ay ae ee he ee . 962°0 
Chloride of sodium. . . . . - ; 271 
Chloride of magnesium . . . Sosy te 54 
Chloride of potassium. . . . . . ae ds o"4 
Bromide of magnesia . ol 
Sulphate of magnesia . ao. & eK 12 
Sulphate of lime . . . . . F il 08 
Carbonate of Lime ol 
leaving a residuum of 2°9, consisting of sulphuretted hydrogen, 
hydrochlorate of ammonia, iodine, iron, copper, and even silver in 
various quantities and proportions, according to the locality of the 
specimen. In examining the plates of copper taken from the bottom 
of a ship at Valparaiso, which had been long at sea, distinct traces 
of silver were found deposited by the sea. Finally, we find dissolved 
in the ocean a peculiar mucus, which seems of a mixed animal and 
vegetable nature, and is apparently organic matter proceeding from 
the successive decomposition of the innumerable generations of 
animals which have disappeared since the beginning of the world. 
This matter has been described by the Count Marsigli, who 
designates it sometimes under the name of g/z, and sometimes as an 
unctuosity. It is the “‘ooze” of marine surveyors, and consists chiefly 
of carbonate of lime, ninety per cent. of which is formed of minute 
animal organisms. Its mealy adhesiveness results from the pres- 
sure of the superimposed water. The numerous salts which exist 
in the sea can neither be deposited in its bed, nor exhaled with 
the vapour, to be again poured upon the soil in showers of rain. 
Particular agents retain these salts in solution, transform them, and 
prevent their accumulation. Hence sea water always maintains a 
certain degree of saltness and bitterness ; and the ocean continues to 
present the chemical characters which it has exhibited in all times, 
varying only in certain localities where more or less fresh water is 
poured into the sea basin from rivers ; thus, the saltness of the Medi- 
terranean is greater than that of the open ocean, probably because it 
loses more water by evaporation than it receives from its fresh-water 
affluents. For the opposite reason, the Black and the Caspian Seas 
are less charged with these salts. The Dead Sea is so strongly 
