282 



Grooher — Influence of a Series Spark 



The observations of Farwell were essentially con- 

 firmed. There was one phenomenon, however, very pro- 

 nounced and fairly regular, which Farwell mentions only 

 occasionally. If a short spark is placed in series with the 

 corona tube, at atmospheric pressure, a few bright radial 

 pencils or streamers of light will shoot out regularly 

 from the wire toward the tube (see fig. 2c) ; these 

 streamers increase in number and in brightness as the 



Fig. 1. 



ELECTRICAL CONNECTIONS 



40 Generators 500v 



r^ol.-- 



spark gap is opened and may at times completely fill 

 the tube with purple light. The phenomenon is very 

 beautiful indeed, especially in hydrogen or illuminating 

 gas, where the streamers fill the tube with an almost uni- 

 form white or blue-green light. Occasionally the begin- 

 ning positive streamers remind us of the negative beads, 

 so that we have as it were a reversal of the phenomena 

 through the spark. The originally uniform positive 

 glow breaks up into streamers, the negative beads go over 

 into a more or less uniform glow. A closer observation, 

 however, of the positive and negative corona with a 

 spark in series shows always differences so conspicuous 

 that one would hardly conclude that the effect is due to 

 oscillations. If there were oscillations, they could not be 



