MORSE. 



THE KATHODO-LUMINESCENCE OF FLUORITE. 



lengths of the spectra produced by fluorescence 10 and by thermo-luni- 

 inescence 1] - shows immediately that while the spectra are similar in 

 general appearance, and while the strong lines in the kathodo-spectra are 

 in about the same part of the spectrum as those in the fluorescence- 

 spectra, there are no coincidences of importance. The three lumines- 

 cences are totally different as far as the wave-lengths of the principal 

 lines are concerned. And a moment's consideration of the facts about 



10 The Fluorescence Spectrum of Fluorite, Astrophysical Journal, 21, 83, 

 (Mar. 1905) ; Studies on Fluorite, I. These Proceedings, 41, 587 (Mar. 1906). 



11 Studies on Fluorite, II. These Proceedings, 41, 593 (Mar. 1906). 



