Discharge in a Magnetic Field. 



259 



1 



When the coil is arranged to give an intermittent direct dis- 

 charge in the secondary only, one semicircle of light appears, 

 as shown in fig. 25 ; and when the current is reversed, it is 



as in fig. 2b*. 



Fie:. 25. 



Fi«r. 26. 



c 



These experiments led me to try another, which may have 

 some bearing on the reason for the zigzag form of the dis- 

 charge in air. Taking once more the vacuum-tube and 

 placing it in the magnetic field, I permitted a very consider- 

 able alternate current to traverse the tube. First, the two 

 columns of bands appear ; then the lines of force ; and 

 finally these phenomena remain, with an additional one, 

 namely, a series of zigzag discharges throughout the tube, 

 permanent in character, but varying their form continually. 

 It is quite possible that these zigzag discharges consist of de- 

 formed bands which meet and form zigzag or sinuous lines. 

 That they should vary in form may possibly be in consequence 

 of the ever-changing temperature of the gases within the tube, 

 due to so large a current passing. Hence it is not impossible 

 that the zigzag discharge in air is due to the magnetic pro- 

 perties of the current itself. Of course further experiment is 

 needed to demonstrate the truth of what I have suggested as 

 a probability. 



U 2 



