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Prof. J. A. Fleming. Conversion of Electric [Jan. 24, 



Table I. Variation of Current through, and Conductivity of, a 

 Vacuum Valve with varying Electromotive Force, the Electrodes 

 being an Incandescent Carbon Cathode and Cool Aluminium 

 Anode. 



conduction in rarified gases.* It may be noted that there is in these 

 current-voltage and voltage-conduction curves a general resemblance to 

 the magnetisation and permeability curves of iron. 



To examine further the nature of this conduction, the following 

 experiments were made. If a vacuum bulb, as described, is joined up 

 in series with a galvanometer and an electrodynamometer and an 

 alternating electromotive force applied to the circuit, the two instruments 

 will both be affected. The galvanometer is, however, affected only by . 



* See J. J. Thomson, ' Conduction of Electricity through Gases/ Chap. VIII. 



