498 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL, 54 



In Brauner's second ^ paper six determinations are given, one being 

 affected by a misprint, whicb is corrected by a citation in Abegg's 

 Handbuch : " 



2.3500 

 2.1052 

 1.0010 

 1.3807 

 1.5275 



.0086 



Mean, 57.472, 



Hence La = 138.30. 



Brauner's weighings are all reduced to a vacuum. 



Both Bauer and Bettendorff made their determinations of the atomic 

 weight of lanthanum by the same general method. Bauer's data ^ are 

 as follows: 



.6431 grm. I^EoOs gave 1.1171 sulphate. 

 .7825 " 1.3613 



1.0112 " 1.7571 



.7325 " 1.2725 



Hence La = 138.76. 

 Bettendorff found ■* — 



.9146 grm. La.Oa gave 1.5900 sulphate. 

 .9395 " 1.6332 



.9133 " 1.5877 



1.0651 " 1.8515 



57.569 per cent. 



57.482 



57.549 



57.564 



Mean, 57.541, ± .0136 



57.522 per cent. 



57.525 



57.523 



57.526 



Mean, 57.524, ± .0006 

 Hence La = 138.G5. 



The few determinations by Wolcott Gibbs ° were made by the oxalate 

 method, which is described in the chapter on cerium. Their purpose, 

 however, was rather to test the method than to definitely fix an atomic 

 weiglit. The data given are as follows, with the ratio 3C203:LaoOa 

 added : 



I/OoOj. C0O3. Ratio. 



45.61 30.15 151.327 



45.64 30.07 151.729 



30.08 151.679 



Mean, 45.625 30.11 151.528 



Mean, 151.566, ± .0607 



Hence La = 139.71. 



1 Monats. Chem., 3, 48G. 



" Band 3, Abth. 1, p. 240. Brauner's discussion of the atomic weight. 



^ Inaugural Dissertation, Freiburg, 18S4. 



•* Liebig's Annalcn, 256, 168. 180O. 



^ Proc. Amer. .\cad., 28, 260. 1893. 



