172 Mr. C. E. S. Phillips. Action of Magnetised Electrodes 



" The Action of Magnetised Electrodes upon Electrical Discharge 

 Phenomena in Earefied Gases. Preliminary Note." By 

 C. E. S. PHILLIPS. Communicated by Sir WILLIAM CBOOKES. 

 Eeceived November 30, Eead December 15, 1898. 



The experiments herein described were undertaken in order to ascer- 

 tain what would be the action of strongly magnetised electrodes upon 

 electrical discharge phenomena in rarefied gases, and especially upon 

 the charged residual gas, when all external stimulation had ceased. 



For this purpose an apparatus was constructed, as shown in Fig. 1, 

 consisting of a soda-glass bulb, B, open at both ends for the purpose of 

 inserting the pointed soft iron electrodes, Ej and E 2 , and with the 

 leading tube L attached for connection to a Sprengel air pump. 



FIG. 1. 



No precaution was taken to keep mercury vapour out of the bulb B 

 during the experiments. Each electrode had a screw thread of suitable 

 pitch cut upon it, in order that the brass cups C T and C 2 , when screwed 

 into position and sealed with cement to the glass, might serve to keep 

 the electrodes central, to reduce the possibility of their rushing 

 together under the influence of strong magnetic forces, and to seal 

 .air-tight the two ends of the bulb. 



The poles of a large electro-magnet, Mj M , were insulated from the 

 electrodes by means of two thin glass sheets, G x G 2 . A discharge from 

 the secondary of an induction coil or other suitable source, could then 

 be passed through the bulb, the exhaustion varied and the electrodes 

 magnetised at pleasure. 



Results. 



A pressure was obtained within the bulb, such that cathode rays 

 began to be freely emitted by the negative electrode, and from the 



