4 P. T. Cleve, 



quantities of samarjia with sulplauric acid, I obtained as a mean of six 

 experiments the number 150.02 (maximum 150.12, minimum 149. 94)^ 

 assuming for the oxide the formula SmaO;.. This number agrees as well 

 as could be desired with Marignac's determination of the atomic weight 

 of Y^, viz. 149.4. 



SPECTRUM OF SAMARIUM. 



The chloride of samarium gives a spark-spectrum, composed of a 

 great number of lines, for the most part of little intensity. They have 

 been very carefully mapped by Professer Thalén') who has registered 198 

 lines of samarium. A great number of them were formerl)^ attributed to 

 didymium. Many of the samarium-lines were also observed by Roscoe 

 and Schuster^) and by them attributed to terbium. 



The absorption-spectrum of samarium has been described by Lecoq 

 BE Boisbaudran, by Soret'), and by Thalén. Their descriptions agree 

 perfectly and according to them the wave-lengths of the bands are: 



559—556 yellow 



497—500 ' » 



486—472 (strong) blue 



466 — 460 (strong) » 



445—437 (weak) » 



419—415 violet 



409 — 401 (very intense) » 



There are also, according to Soret, several absorption-bands in 

 the ultra-violet part of the spectriun, the wave-lengths of which are 



375—373 



364—360 



344 



Becquerel^) also discovered in the infra-red some absorption-bands 

 with wave-leiigths 1145 and 1040. 



') Ofversigt af K. Sv. Vet. Akad. Förh. 1883 N:o 7, 3. 

 ■i) Journ. of the chem. Soc. XLI, 1882. 283. 

 •^) Arch, de sc. ph. et nat [3] IV, 261. 

 '') Ann. de chim. et de phys. [5] XXX, 5. 



