LANTHANUM. 233 



Czudnowicz* based his determination of the atomic 

 weight of lanthanum upon one analysis of the air-dried 

 sulphate. The salt contained 22.741 per cent, of water. 



.59S grm. gave .272 grm. La.^Og and .586 grm. BaSO^. 



The LaoOg was found by precipitation as oxalate and ig- 

 nition. The BaSO^ was thrown down from the filtrate. 

 Reduced to the standards already adopted these data give 

 for the percentage of La2 03 in the anhydrous sulphate the 

 figure 58.008. 79.117 parts of the salt are proportional to 

 100 parts of BaSO,. 



Hermann t studied both the sulphate and the carbonate 

 of lanthanum. From the anhj^drous sulphate, by precipi- 

 tation as oxalate and ignition, the following percentages of 

 Laj 3 were obtained : 



57.690 



57-663 



57.610 



Mean, 57.654, ±: .016 



The carbonate, dried at 100°, gave the following percent- 

 ages: 



68.47 La^g. 

 27.67 CO.^. 

 3.86 H^O. 



Reckoning from the ratio between CO, and La2 03 the 

 molecular weight of the latter becomes 325.896. 



Zschiesche'sl experiments consist of six analyses of lan- 

 thanum sulphate, which salt was dehydrated at 230°, and 

 afterwards calcined. I subjoin his percentages, and in a 

 fourth column deduce from them the percentage of LajOj 

 in the anhydrous salt : 



*Journ. fiir Prakt. Chem., 80, t^^. i860, 

 fjoum. fiir Prakt. Chem., 82, 396. 1861. 

 JJourn. fiir Prakt. Chem., 104, 174. 



