﻿High- 
  Frequency 
  Discharges 
  in 
  Geissler 
  Tubes. 
  969 
  

  

  oscillatory 
  discharge, 
  the 
  frequencies 
  of 
  discharge 
  employed 
  

   were 
  also 
  obtained, 
  and 
  for 
  this 
  purpose 
  a 
  portable 
  wavemeter 
  

   was 
  used. 
  This 
  consisted 
  of 
  a 
  variable 
  Cossor 
  air 
  condenser, 
  

   across 
  the 
  terminals 
  of 
  which 
  different 
  inductances 
  could 
  

   be 
  attached, 
  enabling 
  the 
  experimenter 
  to 
  tune 
  up 
  to 
  different 
  

   frequencies. 
  Standardization 
  of 
  this 
  portable 
  wavemeter 
  

   with 
  the 
  Fleming 
  cymometer 
  enabled 
  curves 
  to 
  be 
  drawn 
  

   connecting 
  the 
  frequency 
  and 
  condenser 
  scale 
  reading, 
  a 
  

   graph 
  for 
  each 
  tuning 
  coil 
  being 
  obtained. 
  A 
  neon 
  tube 
  

   was 
  usually 
  connected 
  across 
  the 
  condenser 
  terminals 
  of 
  the 
  

   wavemeter, 
  and 
  when 
  exact 
  tuning 
  was 
  attained, 
  the 
  neon 
  

   tube 
  glowed 
  brightly 
  with 
  its 
  characteristic 
  orange-red 
  

   glow. 
  

  

  Method 
  of 
  Producing 
  the 
  Discharge. 
  

  

  Various 
  methods 
  of 
  direct 
  and 
  inductive 
  coupling 
  were 
  

   employed 
  between 
  the 
  generating 
  and 
  discharge 
  circuits. 
  

   Two 
  of 
  these, 
  however, 
  were 
  found 
  to 
  be 
  particularly 
  suitable, 
  

   and 
  these 
  were 
  generally 
  used. 
  In 
  the 
  later 
  stages 
  of 
  the 
  

   work 
  it 
  was 
  found 
  that 
  by 
  an 
  adaptation 
  of 
  these 
  methods, 
  

   the 
  discharge 
  could 
  be 
  safely 
  maintained 
  in 
  glass 
  tubes 
  with 
  

   internal 
  electrodes, 
  without 
  breakage, 
  which 
  seemed 
  inevitable 
  

   in 
  the 
  earlier 
  work. 
  This 
  was 
  of 
  great 
  service, 
  particularly 
  

   owing 
  to 
  the 
  fact 
  that 
  the 
  ordinary 
  condensed 
  discharge 
  

   spectrum 
  of 
  a 
  gas 
  cannot 
  be 
  obtained 
  when 
  external 
  electrodes 
  

   are 
  used, 
  so 
  that 
  one 
  could 
  not 
  legitimately 
  hope 
  to 
  obtain 
  

   the 
  condenser 
  spectrum 
  using 
  the 
  Poulsen 
  discharge 
  with 
  

   external 
  electrodes. 
  

  

  Fisr. 
  2. 
  

  

  

  

  5 
  c 
  

  

  + 
  

  

  

  

  X 
  

  

  i 
  A 
  

  

  1 
  

  

  Cu 
  

  

  / 
  

  

  c 
  

  

  480 
  Voltj 
  ) 
  

   1 
  

   1 
  A 
  

  

  < 
  

  

  Carton 
  

  

  o 
  

  

  

  

  

  

  

  5 
  

  

  

  To 
  APPARATv: 
  

  

  (a) 
  This 
  method 
  will 
  be 
  most 
  clearly 
  understood 
  by 
  

   reference 
  to 
  fig. 
  2, 
  which 
  shows 
  the 
  general 
  arrangement 
  of 
  

   Phil. 
  Mag. 
  S. 
  6. 
  Vol. 
  25. 
  No. 
  156. 
  Dec. 
  191?. 
  3 
  U 
  

  

  