1881.] Identity of Spectral Lines of Different Elements. 231 



6449"27. This is rather a wide double, the calcium line being more 

 refrangible than that of barium. 



6461*98. This is a close double, but the iron is less refrangible than 

 the calcium line. 



6438*35. A wide double, the cadmium more refrangible than the 

 calcium line. 



6407'38. The iron line is decidedly more refrangible than the 

 strontium line. 



4690*69. Not resolved before only from the faintness of the iron 

 line, which is less refrangible than the titanium line. 



Figure representing the arrangement of crucible by which most of the observa- 

 tions in the foregoing paper were made, a, block of dense magnesia ; b, horizontal 

 hole for observation ; c, upper perforated carbon through which substances were 

 dropped into the arc • d, lower carbon, sometimes drilled and filled with metal ; 

 e, connexion for positive electrode ; /, connexion for negative electrode ; g and h, 

 brass pillars fixed on wooden block. 



VOL. XXXII. 



I? 



