144 THE ATOMIC WEIGHTS. 



These series combine with that of Dumas as follows : 



Dumas 44. 261 , rb .0200 



Richards and Parker, second series 44.142, ± .0043 



Richards and Parker, third series 44.138, zfc .0013 



Richards and Parker, fourth series 44. 137, ± .0003 



General mean 44. 138, zh .0003 



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

 series of Richards and Parker appear alone. 



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

 weight of magnesium : 



(l.) MgSO^ : BaSO^ : : 100 : 194.003, =b .021 



(2.) MgO : MgSO^ : : 100 : 298.210, d= .0103 



(3.) Per cent, of water in MgSO^, 7H.fi, 51.21, =b .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 : MgCIj : : 100 : 44.138, ± -0003 



(8.) 2AgCl : MgClj : : 100 : 33.226, it .0013 



To reduce these ratios we have — 



• O = 15.879,1^.0003 C := 11.920,^.0004 



Ag ^ 107.108, it .0031 Ba =136.392,^.0086 



CI = 35.179, ± .0048 AgCl = 142.287, ± .0037 

 S = 31.8-28, ± .0015 



For the molecular weight of MgSO^, two values are now calculable : 



From (i) Mg.SO^ = 119.450, =b .0137 



From (3) " = 119.239, zb. 0675 



General mean MgSO^ = 1 19.443, ± .0135 



Hence Mg = 24.099, ± .0136. 

 For MgO, three values are found : 



From (2) MgO ^40.091, zb .0023 



From (4) " = 40.404, =b .0037 



From (5) " =39 721, zb .0021 



General mean MgO = 39.974, zb .0014 



Hence Mg = 24.095, ± .0014. 

 For MgCL there are two values : 



From (7) MgCl^ = 94-551, =!= .0032 • 



From (8) " =94.553,^.0044 



General mean MgClj = 94-552, zb .0026 



Hence Mg = 24.194, ± .0099. 



