16 PHYSICAL GEOGRAPHY OF THE SEA, AND ITS METEOROLOGY. 



45. By examining in Yalparaiso the copper that had been a great 

 Quantity of silver in while on the bottom of a ship, the presence of silver, 

 the sea. which it obtained from the sea, was detected in it. 

 It was in such quantities as to form the basis of a calculation, by 

 which it would appear that there is held in solution by the sea a 

 quantity of silver sufficient to weigh no less than two hundred 

 million tons, could it all, by any process, be precij^itated and col- 

 lected into a separate mass. 



46. The salts of the sea, as its solid ingredients may be called. 

 Its inhabitants- caii neither be precipitated on the bottom, nor taken 

 their offices. -^p ]jj i\^q yapours, noT returned again by the rains 

 to the land ; and, but for the presence in the sea of certain agents 

 to which has been assigned the task of collecting these ingredients 

 again, in the sea they would have to remain. There, accumu- 

 lating in its waters, they would alter the quality of the brine, in- 

 jure the health of its inhabitants, retard evaporation, change 

 climates, and work endless mischief upon the fauna and the flora 

 of both sea, earth, and air. But in the oceanic machinery all this 

 is prevented by compensations the most beautiful and adjustments 

 the most exquisite. As in the atmosphere the plants are charged 

 with the office of purifying the air by elaborating into vegetable 

 tissue and fibre the impmities which the animals are continually 

 casting into it, so also to the mollusks, to the madrepores, and 

 insects of the sea, has been assigned the office of taking out of its 

 waters and making solid again all this lixi-vdated matter as fast as 

 the dripping streams and searching rains discharge it into the ocean. 



47. As to the extent and magnitude of this endless task some 

 Monnmcnts of their idca may bc fomicd from the coral islands, the marl 

 industry. |^g(jg^ j-i^Q ^IjqH banks, the chalk cliffs, and other 

 marine deposits which deck the sea-shore or strew the land. 



48. Fresh water is composed of oxygen and hydrogen gas in the 

 Analysis of sea- j^roportiou by wciglit of 1 to 8 ; and the principal 

 ^^■'^^^i- ingredients which chemists, by treating small samples 

 of sea-water in the laboratory, have found in a thousand grains are. 



Water 962.0 grains 



Cliloride of Sodium ^I*-'- " 



Chloride of Mairncsium 5.4 „ 



Chloride of Potassium 0.4 „ 



Bromide of Magnesia • . . . . 0.1 „ 



Sulphate of Magnesia 1-2 „ 



Sulphate of Lime 0.8 „ 



Carbonate of Lime 0.1 „ 



Leaving a residuum of 2.9 „ = 1000, 



