1897.] 



071 Cathode Bays. 



423 



by the magnet. Thie luminous patch on the glass is crossed by bands 

 along which the luminosity is very much greater than in the adjacent 



Fir.. G.— Air. 



Fig. 7.— Carbonic Acid Gas (Ammeter, 12; Voltmeter, 1600). 



parts. These bright and dark bands are called by Birkeland, who 

 first observed them, " the magnetic spectrum." The brightest places 



2 F 2 



