596 



Stoney — Cause of Double Lines in Spectra. 



Series D of lines that are diffuse, that form a definite pattern when plotted down 

 on a map, and in each pair of which the less refrangible line is the stronger. 



Series D. 



Series S of lines that are sharp, that form a definite pattern, and in each pair of 

 which the less refrangible line is the stronger — 



