ATOMIC WEIGHTS 



501 



care, and with all corrections applicrl, includino; the reduction to a 

 vacuum, follows : 



Mean, 57.5843, ± .00075 



Hence La = 139.05. 



The oxalate series of determinations by Branner and Pavlicek is less 

 satisfactory than this sulphate series, although it leads to sensilply the 

 same value for the atomic weight of lanthanum. Rejecting one experi- 

 ment in their series, which is thrown out as abnormal by the authors, 

 their percentages are as given in the next table, together with the usual 

 ratios : 



.0543 



.OGOr. The general 



Hence La = 139.08. 



The Gibbs value for the same ratio is 151.566, 

 mean of both series is 151. 246, ±.0400. 



In a criticism of Jones' determinations by the sulphate method 

 Brauner ' reiterates his statements concerning the acid salt, and also 

 suggests other sources of error, such as contamination of the lanthanum 



1 Zeitsch. anorg-. Chem., 33, 317. 1903. 



