ON WAVE-LENGTH TABLES OF THE SPECTBA OF THE ELEMENTS. 417 

 Lanthanum— continued. 



* Arc Spectrum. 



Lead. 



* Observed also by Leeoq ile Boisbaudian in the Spark Spectrum between metallic poles, 

 t o served also by Lockyer : the 'indices' denote the 'lengths' of these lines. 

 5 See Tellurium. || See Silver. *» 4387-3 Kirchhoff. 



