THE DOPPLER EFFECT IN ELECTRODLESS DISCHARGE. 



BY FRANK F. ALMY. 



(Abstract.) 



It would appear that if the source of luminosity is in motion in the 

 ring electrodeless discharge, that there should be a broadening of the 

 spectral lines when viewed in the lirle of motion. 



A spherical bulb 5I/2 inches in diameter after having been thoroughly 

 washed with hydrogen, was filled with hydrogen at a pressure of 

 0.15 mm. The spectrum showed no air lines. This bulb was used as 

 the secondary of a Tesla transformer and when in action showed a 

 luminous diametral ring about 2 inches deep. 



From the data at hand, if the luminous source was moving with the 

 maximum velocity which the positive ions should acquire in the ring 

 discharge there should be a broadening of the hydrogen lines of the 

 spectrum, due to the Doppler effect when viewed in line of motion, 

 amounting to 1 Angstrom unit. 



The spectrum was examined by means of large Rowland concave 

 grating capable of showing easily one-fiftieth of this effect. The spectra 

 were photographed when the light came off tangential to the ring dis- 

 charge and again with the light coming radially from the ring dis- 

 charge. There was no observable difference in the character or posi- 

 tion of the spectral lines in the two positions. 



There can be no question that the ions acquire considerable velocities 

 in the electrodeless ring discharge; and that these velocities will alter- 

 nate in direction with the alternations of electric force in the Tesla 

 transformer. The inference would seem to follow that the luminosity 

 of the electrodeless discharge does not occur when the velocity of ions is 

 large, but rather at the ends of their paths at the time that the direction 

 of their motion is reversed. 



