32 • History of physical Science from , [July, 



Muriate of soda 12-2 



Sulphate of soda 5-5 



Sulphate of lime 4*1 



Sulphate of magnesia 1*7 



23^5 

 (Royal Institution Journal, v. 60.) 



2. Saltness of the Sea. — M. Lamarche, in a voyage from Rio 

 Janeiro to France, in the year 1816, collected sea water from the 

 surface of the ocean in different latitudes, and delivered them in 

 sealed bottles to Gay-Lussac. The specific gravity and saline 

 contents of these specimens were determined by M. Despretz in 

 Gay-Lussac's laboratory with all the requisite care. The follow- 

 ing table indicates the results obtained. The first specimen 

 denominated Calais, was taken up by Gay-Lussac himself in 

 the mid-channel between Calais and Dover. 



(Ann. de Chim. et de Phys. vi. 426.) 



Dr. Murray, in his late excellent analysis of the water of the 

 Frith of Forth, found the saline constituents to amount to only 

 about three per cent. But this estimate is certainly below the 

 truth. The specific gravity of the water of the Frith of Forth is 

 1*029, which is greater than the mean of the preceding table. 

 Its saline contents, therefore, must be at least 3-65 per cent. I 



