Manchester Memoirs, Vol. xtviii. (1904), No. 10. 5 



circuit of a condenser.* On increasing the self-induction 

 considerably, it was found that the negative bands 

 gradually disappeared, and were replaced by the positive 

 bands. The gradual change from the negative to the 

 positive band spectrum is shown in Fig. 5. Here the 

 self-induction varied from 0*04 henry (top), to 07 henry 

 (bottom). In the top spectrum the negative bands at 

 3914 and 4278 are well developed, and there are hardly 

 any traces of positive bands. In the bottom spectrum 

 the positive bands are fully developed, and the negative 

 bands have disappeared. 



3. — Glow Discharge in Hydrogen. 



The electrodes were enclosed in a glass bulb through 

 which a steady current of dry hydrogen was passing 

 continuously. One of the electrodes was formed by a 

 bent copper or platinum wire through which a current 

 from a battery could be sent to heat it. (See Figure^ 



The other electrode consisted of a brass sphere or copper 

 rod ; the distance between the electrodes was about i cm. 

 When the oscillatory spark discharge was started no glow 

 was at first visible. But as soon as a current was sent 



^ Hemsalech, Thhes cU la Faculti des Sciences, p. iii, Paris, 1901. 



