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, loo oxygen, 

 1 2 -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 962-0 



Chloride of sodium 27 'i 



Chloride of magnesium 5 '4 



Chloride of potassium 0'4 



Bromide of magnesia O'l 



Sulphate of magnesia I '2 



Sulphate of lime o'8 



Carbonate of Lime • O'l 



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 gin, and sometimes as an 

 iinctnosity. 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, transfomi 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 opjwsite reason, the Black and the Caspian Seas 

 are less charged with these salts. The Dead Sea is so strongly 



