LANTHANUM. 347 



Hermann * studied both the sulphate and the carbonate of lanthanum. 

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

 the following percentages of La 2 O 3 were obtained : 



Mean, 57.654, .016 



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



68.47 La 2 3 . 



27.67 C0 2 . 



3.86 H 2 0. 



Reckoning from the ratio between C0 2 and La 2 O 3 , the molecular weight 

 of the latter becomes 324.254. 



Zschiesche's f 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 2 3 in the anhydrous salt : 



H^O. SO 3 . La-iO^ La z O 3 in Anhydrous Salt. 



22.629 33-470 43.909 56.745 

 22.562 33.306 44.132 5 6 .9 6 4 

 22.730 33.200 44.070 57-34 

 22.570 33-333 44.090 56.947 

 22.610 33.160 44.24 57- I 5 



22.630 33-05 1 44-3 10 57.277 



Mean, 57.021, .051 



Erk J found that .474 grm. of La 2 (S0 4 ) 3 ,by precipitation as oxalate and 

 ignition, gave .2705 grm. of La 2 3 , or 57.068 per cent. .7045 grm. of the 

 sulphate also gave .8815 grm. of BaS0 4 . Hence 100 parts of BaS0 4 are 

 equivalent to 79.921 of La 2 (S0 4 ) 3 . 



From Cleve we have two separate investigations relative to the atomic 

 weight of lanthanum. In his first series strongly calcined La 2 3 , spec- 

 troscopically pure, was dissolved in nitric acid, and then, by evaporation 

 with sulphuric acid, converted into sulphate : 



1.9215 grm. La 2 O 3 gave 3.3365 grm. sulphate. 57-59 P er cent. 



* Journ. fur Prakt. Chem., 82, 396. 1861. 



t Journ. fur Prakt. Chem., 104, 174. 



I Jenaisches Zeitschrift, 6, 306. 1871. 



g K. Svensk. Vet. Akad. Handlingar, Bd. 2, No. 7. 1874. 



