500 s:mithsoisiax miscellaxeous collections vol. 54 



are vitiated by this error. The authors give three series of syntlieses 

 of the sulphate, in which corrections for the acid salt are applied. First, 

 there is a preliminary series, with weights in air. The data, with the 

 acid correction, are as follows, representing eight different fractions of 

 the oxide : 



0047 



Corrected to a vacuum this mean becomes 57. 564, ±.0047. Hence 

 La = 138.91. Its significance, however, is diminished by the fact that 

 the fractions show a progressive change in composition, which appears 

 in the percentage column. The later fractions are higher in LaoOg than 

 the earlier ones. 



The next set of syntheses, representing a different series of lanthanum 

 preparations, gave the subjoined results, corrected for acid sulphate, but 

 with weights in air: 



Mean, 57.558, ± .0048 



Corrected for weighing in air this becomes 57.550. La= 138.82. 



This series, like the preceding one, is given by Brauner and Paviicek 

 as preliminary to more exact work, which seems to have been continued 

 by Brauner alone. His final series of figures, determined with extreme 



* These weights are erroneous, either through misprinting in the original or because of copying. 

 The percentage given is that calculated by Brauntr ant] Paviicek. 



