222 THE ATOMIC WEIGHTS. 



.042 



Beringer also gives a single analysis of the formate and 

 the results of one conversion of the sulphide into oxide. 

 The figures are, however, not valuable enough to cite. 



The foregoing data involve one variation from Beringer's 

 paper. AVhere T put CeO, as found he puts Ce^Oa. The 

 latter is plainly inadmissible, although the atomic weights 

 calculated from it agree curiously well with some other 

 determinations. For instance, in the chloride series, the 

 assumption of CcaOg as the formula of the oxide obtained, 

 gives Ce = 137.749, while CeOa makes Ce = 141.636. The 

 former agrees with the results of Wolf, Wing, and others 

 (juite fairly ; the latter is near the value obtained by Biihrig. 

 Obviously, the presence of didymium in the salts analyzed 

 should tend to raise rather than to lower the apparent atomic 

 weight of cerium. 



Shortly after Beringer, Hermann * published the results 

 of one experiment. 23.532 grm. of anhydrous cerium sul- 

 phate gave 29.160 grm. of BaSO^. Hence 100 parts of the 

 sulphate correspond to 123.926 of BaSOi. 



In 1848 similar figures were published by Marignac,t 



who found the following amounts of BaSO^ proportional to 



100 of dry cerium sulphate : 



122.68 

 122.00 

 122.51 



Mean, 122.40, d: .138 



If we give Hermann's single result the weight of one ex- 

 periment in this series, and combine, we get a mean value 

 of 123.019, ± .113. , 



* Journ. fiir Prakt. Chem., 30, 185. 1843. 



f Arch, des Sciences Phys. et Nat., (i,) 8, 273. 1848. 



