350 THE ATOMIC WEIGHTS. 



Iii all, there are six ratios from which to calculate : 



(i.) Percentage of La. 2 O 3 in La 2 (SO 4 ) 3 , 57.522, .00059 



(2.) 3BaCl. 2 : La 2 (SO 4 ) 3 : : ioo : 91.322, .048 Marignac 



(3.) 3BaSO 4 : La 2 (SO 4 ) 3 : : ioo : 80.054, .270 



(4.) 3BaSO 4 : La 2 O 3 : : ioo : 46.671, .075 Holzmann 



(5.) Percentage of La 2 O 3 in iodate, 23.447, dr .0216 Holzmann 



(6.) Percentage of La 2 O 3 in magnesian nitrate, 21.3056, .058 Holzmann 



Hermann's single experiment on the carbonate is omitted from this 

 scheme as being unimportant. 



For the reduction of these data we have 



O= 15.879, zh. 0003 N :: 13.935, .0021 



Cl 35.179, .0048 C = 11.920, .0004 

 I = 125.888, .0069 Mg = 24. ioo, =b .001 1 



S = 31.828, -0015 Ba == 136.392, .0086 



For lanthanum sulphate two values are obtainable : 



From (2) La 2 (SO 4 ) 3 = 566.425, .2999 



From (3) " = 556.542,^1.8729 



General mean Ln 2 (SO 4 ) 3 = 566. 182, rh .2961 



Hence La = 140.075, .1481. 



For the oxide there are four independent values, as follows : 



From (i) La 2 O 3 = 322.825, .0090 



From (4) " = 322.460,^.5215 



From (5) " =320.726,^.3159 



From (6) " = 322.904, .9107 



A glance at these figures shows that the first alone deserves considera- 

 tion, and that a combination of all would vary inappreciably from it. 

 Taking, then, La 2 3 = 322.825, =fc .0090, we get- 

 La = 137.594, =b .0046; 



or, with = 16, La = 138.642. 



If we take the concordant results of Cleve's and Brauner's later series, 

 which give the percentage of La 2 3 in La 2 (S0 4 ) 3 as 57.480, then La = 

 137.316. Possibly this value may be better than the other, but the evi- 

 dence is not conclusive. 



