(/'JL&/J& 



S-S/3 



THE 



LONDON, EDINBURGH, and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE. 





[SIXTH SERIES.] £7 



NOVEMBER 1912. 



LXXI. The Current-Potential Curves of the Oscillatina Spark 

 and the Mechanism of Spark Conduction, By S. R. MttNER', 

 B.Sc, Lecturer in Physics, the University of Sheffield *. 



[Plate XX.] 



THE observations on the current-potential curves of: the 

 spark described below were carried out in order to test 

 a view of the mechanism o£ spark conduction which I had 

 formed as a result of a study of the streamers in the spark 

 made a few years ago f . It was not until after they were 

 finished that I found that similar work has been done by 

 Roschansky J , who has made a detailed study of the voltages 

 in the oscillating spark with different metals, spark-lengths, &c. 

 It nevertheless seems advisable to publish a short account of 

 my results, as they are an extension of Roschansky's in some 

 respects, and also a knowledge of the phenomena is necessary 

 for the theoretical considerations which follow. 



The method of obtaining the curves is the well-known 

 one of employing the simultaneous electric and magnetic 

 deflexions at right angles of a beam of cathode rays — 

 the electric deflexion is produced by the p.d. of the spark, 

 and the magnetic by the spark current. The arrangement 



* Communicated by the Author, 

 f Milner, Phil. Trans. A. ccix. p. 71 (1908). 



+ D. Roschansky, Ann. d. Phys. xxxvi. p. 281 (1911). See also Phys. 

 Zeitsch. ix. p. 627 (1908). 



Phil Mag. S. 6. Vol. 24. No. 143. Nov. 1912. 3 A 



