202 Davis — Electrical Conductivity and Absorption of 



Art. XIX. — The Electrical Conductivity and Absorption 

 of Enerqy in the Electrodeless Discharqe : by Bergen 

 Davis, Ph.D. * ' J 



The current produced in gases by the electrodeless discharge 

 is very intense but of short duration. This current produces, 

 or is accompanied by, great ionization of the gas subject to 

 the discharge. The object of these experiments was to measure 

 the conductivity produced in gases by the discharge at various 

 pressures. Great care was taken to keep the force producing 

 the discharge uniform throughout the series of experiments. 

 The method of doing this will be readily understood from the 

 arrangement of apparatus, which was as follows : 



L L ( fig. 1 ) are four large Leyden jars connected two in series 

 and two in parallel. The inner coatings were connected to the 

 spark gap S, and also by the leads dd to the terminals of the sec- 

 ondary of a large induction coil, which was driven by an alter- 

 nating current of 40 periods per second. The outer coatings were 

 connected to the terminals of the coil C surrounding the vessel 

 Y. A hot wire galvanometer, G, was placed in the discharg- 

 ing circuit for the purpose of regulating and comparing the 

 amount of current passing through the coil C under various 

 conditions. As the potential at which the spark passes and 

 the period are constant, equal currents will represent equal 

 potential gradients around the vessel. Upon the passage of the 

 sparks at S, a strong discharge was produced in the vessel Y. 

 The conductivity produced in the gases by this discharge was 

 measured by the galvanometer M, reading to 10~ 6 amperes, 

 connected as shown in the figure. 



The vessel Y is shown in detailed section in Hg. 2. The 

 part of the vessel through which the discharge passed was the 

 annular space AA, between two cylindrical vessels of different 

 diameters placed one within the other, the edges being united at 



