CERIUM. 343 



To reduce these ratios we have 



O = I5.879,:t.OOO3 C = II.92O, .OOO4 



Cl = 35.179, d= .0048 S = 31.828, zb .0015 



Ag = 107.108, dz .0031 Ba = 136.392, .0086 



i42.287, .0037 



From the ratios, with these intermediate data, we can get two values 

 for the molecular weight of Ce 2 (S0 4 ) 3 , and five for that of Ce0 2 . For 

 cerium sulphate we have 



From (i) ................... Ce 2 (SO 4 ) 3 = 565.404, . 1670 



From (3) ................... " = 568.304, db . 1054 



General mean ......... Ce z (SO 4 ) 3 = 567.478, .0891 



Hence Ce == 140.723, .0451. 

 For eerie oxide the values are 



From (2) ...... ' ................. CeO 2 171.577, .1218 



From (4) ........... . ........... " = 172.746,^.1772 



From (5) ....................... " =r 170.879, .0115 



From (6) ....................... " =172.125,^.0177, 



From (9) ...................... " = 170.557, .0076 



General mean ............. CeO 2 = 170.827, .0060 



And Ce = 139.069, .0061. 



For cerium itself, four independent values are now calculable, as 

 follows : 



From molecular weight of sulphate. . . Ce = 140.723, .0451 



From molecular weight of dioxide ... " = 139.069, rb .0061 



From ratio (8) .................... " = 139.206, .0263 



From ratio (7) ............... ..... " = 140.516, .0047 



General mean ............... Ce = 140. 1 13, =b .0036 



If = 16, Ce = 141.181. 



It must be admitted that this combination is of very questionable 

 utility. Its component means vary too widely from each other, and in- 

 volve too many uncertainties. Furthermore, Schutzenberger and Brau- 

 ner both impugn the homogeneity of the supposed element, as it has 

 hitherto been recognized. Even if no " meta-elements " are involved in 

 the discussion, it seems clear, on chemical grounds, that the two lower 

 values are really preferable to the two higher, and that ratio (7) receives 

 excessive weight. The general mean obtained is probably a full unit too 

 high. The value 139.1 is perhaps nearly correct. 



