Prof. Graham on the Diffusion of Liquids, 255 



thousand grs. of the liquid yielded 35*50 grs. of dry salts, of 

 which 2*165 grs. were magnesia. The dry salts contain there- 

 fore 6*10 per cent, of that earth. 



Six thousand-grain phials, of 1*1 inch aperture, were pro- 

 perly filled with the sea-water and placed in six tumblers, each 

 of the last containing 6 ounces of water. Temperature about 

 50°. The diffusion was interrupted after eight days. The 

 salts of the sea-water were now found to be divided as follows: — 



Diffused into the tumblers . 92*9 grs., or 36*57 percent. 

 Remaining in the phials . . 161*1 grs., or 63*43 percent. 



254*0 100*00 



Rather more than one-third of the salts has therefore been 

 transferred from the solution phials to the water-jars by dif- 

 fusion. 



Of the diffused salts in the tumblers, 46*5 grs. were found 

 to contain 1*90 gr. magnesia, or 4*09 per cent. Hence we 

 have the following result : — 



Magnesia originally in salts of sea-water . 6*01 percent. 

 Magnesia in salts diffused from sea-water . 4*09 per cent. 



The magnesia, also, must in consequence be relatively con- 

 centrated in the liquid remaining behind in the diffusion cells. 



A probable explanation may be drawn from the last results 

 of the remarkable discordance in the analysis of the waters of 

 the Dead Sea, made by different chemists of eminence. I 

 refer to the relative proportion of the salts, and not their ab- 

 solute quantity, the last necessarily varying with the state of 

 dilution of the saline water when taken up. The lake in 

 question falls in level 10 or 12 feet every year, by evaporation. 

 A sheet of fresh water of that depth is thrown over the lake 

 in the wet season, which water may be supposed to flow over 

 a fluid nearly ] *2 in density, without greatly disturbing it. 

 The salts rise from below into the superior stratum by the 

 diffusive process, which will bring up salts of the alkalies with 

 more rapidity than salts of the earth, and chlorides, of either 

 class, more rapidly than sulphates. The composition of water 

 near the surface must therefore vary greatly, as this process 

 is more or less advanced. 



(4.) I may be allowed to add another experiment which is 

 curious for the protracted immobility of a column of water 

 which it exhibits, as well as for the separation occurring, which 

 last may be interesting also in a geological point of view. A 

 plain glass cylinder with a foot, 1 1 inches in height, and of 

 which the capacity was 64 cubic inches, had 8 cubic inches 

 poured into it of a saturated solution of carbonate of lime in 



