Stoney — Cause of Double Lines in Spectra. 



597 



Series S. 



In these Tables — 



\ (the wave-length in air, measured in tenthet-metres) is given by observa- 

 tion. 



K (the "inverse wave-length," the number of waves in the tenth of a milli- 

 metre in air) = \Q^/\. 



T (the periodic time of the oscillation measured in micro-jots) = /x X. 



ju, being the index of refraction of air for that wave-length. 



N (the " oscillation-frequency," i.e. the number of oscillations in each jot of 

 time) = k/ fjL. 



AN (the interval between the constituents of a double line on a map of 

 oscillation frequencies) = Ak//x. 



4P2 



