

1895.] Spectrum of Argon as it appears in that of Air. 295 



It will appear that these lines, which approximate so closely to a 

 large number of lines in the argon spectrum, are scarcely likely to 

 do so by mere chance. There is one group marked by a bracket which 

 may be identified in the spectrum of aluminium in the ' J. Chem. 

 Soc.,' vol. 41, p. 90 (photographs). It will be seen that, compared 

 with others, the spectrum of aluminium No. 4 is rich in well-defined 

 air lines, and the group of lines referred to is that lying immediately 

 below the space between the most prominent lines in the first or 

 least-refrangible triplet in the spectrum of cadmium No. 3. They 



