ATOMIC WEIGPITS 



231 



This series gives slight!}' higher results than the others, and the 

 authors, for reasons which they assign, discard it: 



Third Series. 



MgCk- Ag. Ratio. 



1.99276 4.51554 44.131 



1.78870 4.05256 44.138 



2.12832 4.82174 44.140 



2.51483 5.69714 44.141 



2.40672 5.45294 44.136 



1.95005 4.41747 44.144 



Mean, 44.138, ± .0013 • 

 Hence Mg = 24.315. 



The fourth series, because of the experience gained in the conduct of 

 the preceding determinations, is best of all, and the authors adopt its 

 results in preference to the others : 



Fourth Series. 



MgCJr.. Ag. Ratio. 



2.03402 4.60855 44.136 



1.91048 4.32841 44.138 



2.09932 4.75635 44.137 



1.82041 4.12447 44.137 



1.92065 4.35151 44.138 



1.11172 2.51876 • 44.138 



Mean, 44.137, ± ,0003 

 Hence Mg = 24.313. 

 These series combine with that of Dumas as follows: 



Dumas 44.261, ± .0200 



Richards and Parker, second series. . . . 44.142, rh .0043 



Richards and Parlver, third series 44.138, ± .0013 



Richards and Parker, fourth series 44.137, ± .0003 



General mean 44.138, ± .0003 



Here the first two values practically vanish, and the third and fourth 

 series of Eichards and Parker appear alone. Combining this figure with 

 their value for the AgCl ratio, the subjoined cross ratio appears : 

 Ag: CI:: 100: 32.842. 



To sum up, we now have the following ratios, bearing upon the atomic 

 weight of magnesium : 



(1). MgSO^iBaSO,: :100:194.003, ± .021 

 (2). MgOrMgSO,:: 100: 298.210, ± .0103 

 (3). Per cent, of water in MgSO^, 7H,0, 51.21, ± .020 

 (4). Per cent, of MgO in oxalate, 27.3665, ± .0023 

 (5). Per cent, of MgO in carbonate, 47.627, ± .0018 

 (6). Per cent, of Mg in MgO, 60.2845, ± .0027 

 (7). 2Ag:MgCI.,: :100:44.138, ± .0003 

 (8). 2AgCI:MgCU: :100:33.226, ± .0013 

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