496 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 54 



mim upon one analysis of the air-dried sulphate. The salt contained 

 23.741 per cent, of water. 



.598 grm. gave .272 grm. La.,03 and .586 grm. BaS04 



The La^Oj was found by precipitation as oxalate and ignition. The 

 BaSOi was thrown down from the filtrate. Reduced to the standards 

 already adopted, these data give for the percentage of La^.O., in the anhy- 

 drous sulphate the figure 58.668. 79.117 parts of the salt arc jiropor- 

 tional to 100 parts of BaSO^. Hence La = 146.43 and 132.93. 



Heriiiann ^ studied both the sulphate and the carbonate of lantliar.uin. 

 From the anhydrous sulphate, by precipitation as oxalate and ignition, 

 the following percentages of La^O,, were obtained : 



57.690 

 57.663 

 57.610 



Mean, 57.654, ± .016 



Hence La = 139.51. 



The carbonate, dried at 100°, gave the following percentages: 



68.47 La„0,, 



27.67 CO, 



3.86 H„0 



Reckoning from the ratio between C0„ and La.O.,, the molecular 

 weight of the latter becomes 326.66. 



Zschiesche's ^ experiments consist of six analyses of lanthanum sul- 

 phate, which salt was dehydrated at 230°, and afterwards calcined.. I 

 subjoin his percentages, and in a fourth column deduce from them the 

 percentage of La„03 in the anhydrous salt: 



HX). SO... La.,03. La^Os in anhydrous salt. 



Mean, 57.021, ± .051 

 Hence La = 135.34. 

 Erk' found that .474 grm. of La. ( SOj );.. l)y precipitation as oxalate and 



1 Journ. prakt. Chem., 82, 396. 18(51. 



^ .Journ. prakt. Chem. , 104, 174. 



' Jenaisches Zeitschrift, 6, 306. 1871. 



