ATOMIC WEIGHTS 525 



SAMARIUM. 



According to iVIarignac/ the atomic weight of samarium is 149.4. He 

 gives, however, one analysis of the octoh^^drated sulphate, as follows : 

 1.8515 grammes gave 0.365 of water, and on calcination lost 0.G07 SO3. 

 Hence the percentage of SajOg in the hydrous salt is 47.502, and in the 

 anhydrous sulphate 59.166. From these data Sa = 149.87 and 150.02. 

 Brauner/ with purer material, made Sa = 150.7, but gave no details. 

 The first regular series of atomic weight determinations was by Cleve,'' 

 who effected the synthesis of the sulphate from the oxide. Data as 

 follows : 



Mean, 59.1865. ± .0025 

 Hence Sa= 150.17. 



Another set of determinations l^y Bettendorff,^ after the same general 

 method, gave as follows : 



Mean, 59.227, ± .0038 



Hence Sa= 150.46. 



In a single analysis of the hydrous sulphate, Brauner ' obtained the 

 following figures: 1.36567 grammes Sa,(SOj3.8H,0 gave 1.09770 

 Sa2(S0j3 and 0.65046 SaoO.. Per cent. Sa^Os in hydrate, 47.629; in 

 anhydrous salt, 59.257. Hence Sa = 150.76 and 150.67. 



Kappel/ cited by Muthmann and Weiss, from 4.12673 grammes 

 Sa2(S0j3 obtained 2.45028 Sa-oOg, or 59.376 per cent Hence Sa = 

 151.59. 



1 Arch. Sci. Ph.vs. Nat. (3), 3, 435. 1880. Oeuvres (^mipUHes, 2, 709. 



^Joiirn. Cheni. Soc, 43, 2S7. 1SS3. 



■Joiirn. Chem. Soc, 43, 362. 1883 



* Am. Chem. Pharm., 263, 164. 1891. 



= Abegg-'s Hanclbuch, Bd. 3. Abtli. 1, p. 2S4. 



« Liebip's Annalen, 331, KJ. I^m. 



34 



