Silent Electric Discharge 



77 



THE SILENT ELECTRIC DISCHARGE AND ITS 

 EFFECTS ON GASES. 



R. H. George and K. A. Oplinger, 

 Engineering Experiment Station, Purdue University. 



In order to determine the causes for the erratic behavior of gases 

 when subjected to a silent electric discharge the Engineering Experi- 

 ment Station at Purdue University has been conducting an investigation 

 of alternating current discharge in an attempt to obtain further knowl- 

 edge of its mechanism. This investigation has continued over a period 

 of about four years in conjunction with the problem of the fixation of 

 atmospheric nitrogen by the silent electric discharge.* 



Diagram of Apparatus 



Busv 



I5»,H 



Gas 

 Inlet 



Discharge 

 Chambe-R 



^ZlNC 



Plate 



Bus 



J ENC EKP 3TA 



Fig. 1. Diagram of a corona dischai-ge apparatus and power supply circuits. 



In the beginning only the discharge in air was considered but the 

 problem here was so complex that an attempt was made to .simplify it 

 by studying the discharge in the component gases. The work set forth 

 in this paper is a resume of recent investigations in the two gases, 

 nitrogen and oxygen. 



The discharge chamber as shown in figure 1 is made up of glass 

 plates cemented together at the edges and to the bakelite end pieces. 

 The gas was admitted at each end and allowed to pass out through a 

 small opening in the top near the center of the chamber. The needles 

 used were made by drawing down a 2 mm. glass tube and sealing into 

 it a short piece of tungsten wire 0.27 mm. in diameter which extended 

 out beyond the glass a distance of 3 mm. and was carefully ground to a 

 point. The needles were then centered in the chamber with a distance 

 of 15 cm. between points. Connections were made to the tungsten points 

 by filling the glass tubes with mercury. 



^ See Bulletin No. 9, Engineering Experiment Station, Lafayette, Indiana, for a 

 detailed description of this work. 



'Proc. Ind. Acad. Sci., vol. 33, 1923 (1924)." 



