1881.] Identity of the Spectral Lines of Different Elements. 229 



5] 68*48 is a close double, but the iron is less refrangible than the 

 nickel line. 



5145*87 we could not resolve, but it is not down as an iron line 

 in Thalen's list. 



5142-1 is double, and the iron line the less refrangible, but it 

 was difficult to separate the two lines by reason of their diffuse 

 character. 



5136*9 is a very close double, the iron line more refrangible and 

 weaker than the nickel line. 



4854*85 we have not been able to find any iron line here in the arc. 



Of supposed coincident lines of manganese and iron : — 



5340*38 is a close double of manganese and iron, but still definitely 

 divisible, the iron line being the more refrangible of the two. 



5254*21 is rather a wide double, with the iron line the more re- 

 frangible. 



4489*49, also plainly double, has the iron line more refrangible than 

 the manganese line. 



4414*77 is a close double, but distinctly separable, the iron line the 

 less refrangible. 



4054*48. There is a faint iron line here slightly more refrangible 

 than the manganese line. 



The magnesium and iron lines in b i are separable, the iron line being 

 less refrangible. 



Of chromium lines supposed coincident with iron lines : — 



5207*78 is plainly double, the iron line being the less refrangible. 



5203*88 not clearly resolved, but the iron line seems the less 

 refrangible. 



4654*07. We failed to detect any chromium line at this place, though 

 the chromium line at 4646*6 was bright and strong, as well as a line 

 at 4650*5. 



4646*6 we could not resolve, but Thalen gives no line of iron in his 

 list at this place. 



4369*27 does not appear to be an iron line ; we could detect no 

 stfch. line in the arc, and it is not given in Thalen's list. There is an 

 iron line about one division of Angstrom's scale less refrangible. 



Of supposed coincident lines of iron and cobalt : — 



5265 94 is decidedly double, and the more refrangible of the two 

 lines due to cobalt. 



5352*57 we did not resolve with certainty, but cobalt expanded the 

 line more on the less refrangible side. 



5681*52. The iron line here is decidedly more refrangible than that 

 of sodium. 



We have examined further the supposed coincident lines of cobalt 

 and calcium, and of chromium and calcium, and find that 6121*34 is 

 plainly resolvable, and the cobalt line is the less refrangible of the two. 



