LANTHANUM. 0)4/ 



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

 From the anh3'drous sulphate, ])y precipitation as oxalate and ignition, 

 the followino; percentages of La.,03 were obtained : 



57.690 

 57-663 

 57.610 



Mean, 57.654, ± .016 



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



68.47 La^Og. 



27.67 CO2. 



3.86 Hfi. 



Reckoning from the ratio between CO^ and La.^Og, the molecular weight 

 of the latter becomes 324.254. 



Zschiesche's t experiments consist of six anal3^ses 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^^Og in the anhydrous salt : 



//.^O. SO.^. LaM^. La.jP^ in Anhydrous Salt. 



22.629 33-47° 43-909 56.745 

 22.562 33-306 44-132 56.964 

 22.730 33- 200 44.070 57-034 

 22.570 ll-l>2>7> 44.090 56-947 

 22.610 33- 160 44.240 57- 150 



22.630 33-051 44-310 57-277 



Mean, 57.021, =b -051 



Erk X found that .474 grm. of La2(SOj3, by precipitation as oxalate and 

 ignition, gave .2705 grm. of La.^Og, or 57.068 per cent. .7045 grm. of the 

 sulphate also gave .8815 grm. of BaSO^. Hence 100 parts of BaSO^ are 

 equivalent to 79.921 of La^CSOJ^. 



From Cleve we have two separate investigations relative to the atomic 

 weight of lanthanum. In his first series § strongly calcined La^Og, spec- 

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

 w'ith sulphuric acid, converted into sulphate : 



1. 9215 grm. La^Oj gave 3.3365 grm. sulphate. 57-590 per cent. 



2.0570 " 3-5705 " 57.611 



1.6980 " 2.9445 " 57-667 



2.0840 " 3.6170 " 57-617 " 



1.9565 * " 3-3960 " 57-612 " 



Menn, 57.619, ± .0085 



* Journ. fiir Prakt. Chetn., 82, 396. 1861. 



t Journ. fi'ir Prakt. Cheni., 104, 174. 



IJenaisches Zeitschrift, 6, 306. 1S71. 



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



