1 6 THE OCEAN WORLD. 



anomalies in the laws of freezing and of thermal dilatation, that 

 assist the rays of heat to penetrate its bosom ; the salts of the sea 

 invest it witli adaptations which fresh water could not possess. In 

 the latter case the maximum density would be 39° 5" instead of 

 25° 6", when the dynamical force of the sea would be insufficient 

 to put the Gulf vStream in motion, nor could it regulate those 

 climates we call marine. 



We have said that sea water contains nearly all the soluble sub- 

 stances which exist in the globe. Nevertheless, when evaporated it is 

 comparatively pure. " The water which evaporates from the sea," 

 says Youman, in his " Chemistry," " is nearly pure, containing 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 

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

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

 potassium, 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 (i pint 760773) : — '^ 



Grammes. 



Chloride of sodium 25704 



Chloride of magnesium 2 '905 



Sulphate of magnesia 2"4(>2 



.Sulphate of lime i"2io 



Sulphate of potassium 0*094 



Carbonate of lime . o-i''2 



Silicate of soda 0017 



Bromide of sodium 0"io^ 



Bromide of magnesium 0"0W 



Oxide of iron, carbonate and phosphate of mag- Only 



nesia, and oxide of manganese traces. 



32-657 



* Examen Comixaratif des Principales Eaux iMinerales de France et d'Alle- 

 magne, par MM. L. Figuier et Mialhe. Read at the Academic de Medecin, 

 23rd of May, 1848. 



