304 



The means of these two series of results gives the follow- 

 ing as the true composition of the salt — 



C t 11 ed It / Water, 51.21 



* ' \ Sulphate of magnesia, 48.79 



100 



• i-i i, f Sulphuric acid, . . . 66.67 



Anhydrous salt, j^^ .' . _ . 33.33 



100 

 If the atomic weight of magnesium was 12.7, the composition 

 of the salt would be — 



Crystallized salt, < a , , ', V. .' ' Ann ~ 



J ' ( sulphate 01 magnesia, 49.07 



100 



» i -. u f Sulphuric acid, . . . 65.89 



Anhydrous salt, < A/f l . ' „. ., 



J ' (Magnesia, . . . . 34.11 



100 



If the atomic weight of magnesium was 1 2, the composition 

 of the salt would be — 



n *. ir 1 u ("Water, 51.22 



Crystallized salt, j g^^ rf Magnesia> > 4878 



100 

 Anhydrous 6 a.t, {gg^f-. ] | g^g 



100 

 It will be seen at once how very nearly the atomic weight 

 of 1 2 corresponds with the composition given by experiment. 

 In order to further test the correctness of the conclusion thus 

 arrived at, I added 108.60 grains of anhydrous chloride of ba- 

 rium to 60.05 grains of anhydrous sulphate of magnesia. This 

 gave 116.65 grains of sulphate of barites; to the washings of 

 this I added sulphuric acid, which gave 4.97 grains of sulphate 



