CHAPTER X 

 Sea Water 



Chemistry 



Sea -water is salt to the taste ; very much Salter than 

 fresh water, in which, when we drink it, we are not con- 

 sciously aware that there is any salt. Yet it is, in reality, 

 present, but in exceedingly minute quantities, for all the 

 oceans derive their saltness from the fresh water which 

 pours down from the land in the form of rivers. 



In remote ages one can imagine that the oceans were 

 almost fresh ; the saltness of which we are now aware 

 is due to the accumulation of the minute quantities washed 

 down from the land through countless centuries. It has 

 been estimated that there is enough salt in the oceans to 

 yield fourteen and a half times the bulk of the entire 

 continent of Europe above high-water mark. 



When sea water is evaporated down until it is dry a white 

 crystalline substance, the sea salt, is left. Over three 

 quarters of this salt consists of sodium chloride, the 

 remainder being made up of small quantities of bromides, 

 carbonates and sulphates, of sodium, potassium, calcium 

 and magnesium. 



Practically everywhere in the oceans of the world the 

 composition of sea salt is to all intents and purposes the 

 same, that is the proportions to one another of the different 

 components are the same. But the actual quantity 



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