18 THE OCEAN WOKLD. 



stances which exist in the globe. Nevertheless its exhalation is com- 

 paratively pure. " The water which evaporates from the sea," says 

 Youman, in his " Chemistry," " is nearly pure, containing but very 

 minute traces of salts. Falling as rain upon the land, it washes the 

 soil, percolates through the rocky layers, and becomes charged with 

 saline substances, which are borne seaward by the returning currents. 

 The ocean, therefore, is the great depository of all substances that 

 water can dissolve and carry down from the surface of the continents ; 

 and, as there is no channel for their escape, they would constantly 

 accumulate, were it not for the creatures which inhabit the seas, and 

 utilize the material thus brought within their reach." These sub- 

 stances are chloride of sodium or marine salt, sulphates of magnesia, 

 potassa, lime, and other substances which the water of various seas is 

 found to contain. 



In the year 1847, I made an analysis of water taken a few leagues 

 from the coast at Havre, which gave the following result, from one 

 litre (1 pint -760773) : * 



Grammes. 



Chloride of sodium 25-704 



Chloride of magnesium 2*905 



Sulphate of magnesia 2462 



Sulphate of lime ... 1-210- 



Sulphate of potassa 0'094 



Carbonate of lime 0132 



Silicate of soda 0*017 



Bromide of sodium 0*103 



Bromide of magnesium 0'030 



Oxide of iron, carbonate and phosphate of mag-) Only 

 nesia, and oxide of manganese ... . ( traces. 



32-657 



The water of the Mediterranean contains more salts than that of 

 the ocean. 



The following are, according to M. Usiglio, who was one of a com- 

 mission sent to examine the different kinds of salt water in the south 

 of France, the component parts of one hundred gallons of Mediter- 

 ranean water : 



* Examen Comparatif des Principales eaux Mine'rales Salines de France ct d'AHe- 

 magne, par MM. L. Figuier et Mialhe. Head at the Academic de Medecin, 23rd of 

 May, 1848. 



