ANNUAL OF SCIENTIFIC DISCOVERY. 



sea water alone, and mixed in different proportions, but the gross quantity of 

 the salts in the water being always 3 per cent, of its weight, the results were, 

 that the chlorides acted more rapidly upon the copper, than the sulphates. Of 

 the chlorides that of magnesium acted most ; calcium next, and sodium least. 

 isTow, according to Professor Graham's experiments, chlorides diffuse more 

 rapidly than any other salts. This may give a preponderance of these salts 

 at the mouths of those rivers, and may have a tendency to an increased wear 

 occasionally in such places. 



These important observations and remarks are of the greatest value in the 

 study of the history of the causes that affect the wear of sheathing, and when 

 all the circumstances of this wear are developed, some of the conditions may 

 be found to agree with the observations just cited. 



The quantity of salts held in solution in sea water, except in such as the 

 Dead Sea, which is very dense, may be given at an average of from 3 per cent. 

 to 3 - 8 per cent., of the weight of the water; but the different kinds of salts 

 vary considerably in different localities. In order to set this variation before 

 the reader in the most appreciable form, we have taken the anatysis of 

 different sea waters, and calculated the quantity of salts in the 100 parts. 

 The following table exhibits the results, giving at the same time the quantity 

 of the whole in relation to the water: 



PER CENTAGE OF SALTS. 



It will be seen from this table, that some of the salts held in solution vary 

 considerably in their relation to each other ; the chloride of magnesia ranges 

 very wide, much more so than the chloride of sodium, or common salt, from 

 the variety in the quantity of salts in the water, which will necessarily cause a 

 great variet} r in the specific gravity of these waters, especially at the mouths 



