﻿Resistance 
  of 
  Gases 
  during 
  an 
  Oscillatory 
  Discharge. 
  339 
  

  

  consisted 
  of 
  a 
  step-up 
  transformer 
  consisting 
  of 
  two 
  secondaries 
  

   of 
  many 
  turns 
  of 
  tine 
  wire 
  which 
  were 
  slipped 
  upon 
  a 
  long 
  

   primary. 
  When 
  the 
  secondaries 
  were 
  coupled 
  in 
  series 
  the 
  

   electromotive 
  force 
  of 
  the 
  discharge 
  was 
  doubled, 
  without 
  any 
  

   considerable 
  change 
  in 
  the 
  capacity. 
  As 
  a 
  matter 
  of 
  fact, 
  the 
  

   glow 
  was 
  seen 
  to 
  be 
  perceptibly 
  redder 
  with 
  two 
  coils 
  than 
  

   with 
  one, 
  showing 
  that 
  the 
  change 
  in 
  the 
  quantity 
  is 
  the 
  essen- 
  

   tial 
  feature 
  in 
  the 
  change 
  of 
  the 
  spectrum. 
  

  

  While 
  this 
  conclusion 
  interferes 
  with 
  the 
  strict 
  application 
  

   of 
  the 
  word 
  talantoscope 
  to 
  an 
  argon-tube, 
  the 
  use 
  of 
  the 
  tube 
  

   as 
  a 
  talantoscope, 
  nevertheless, 
  remains; 
  for 
  while 
  the 
  oscilla- 
  

   tions 
  and 
  the 
  blue 
  spectrum 
  are 
  not 
  strictly 
  dependent 
  upon 
  

   one 
  another, 
  they 
  are 
  both 
  dependent 
  upon 
  the 
  same 
  final 
  

   cause. 
  

  

  The 
  conclusion 
  that 
  the 
  large 
  quantity 
  of 
  electricity, 
  and 
  

  

  therefore, 
  the 
  high 
  temperature 
  caused 
  by 
  the 
  discharge, 
  is 
  the 
  

  

  cause 
  of 
  the 
  very 
  much 
  diminished 
  resistance 
  of 
  the 
  tube 
  and 
  

  

  the 
  corresponding 
  spectrum, 
  leads 
  us 
  at 
  once 
  to 
  consider 
  the 
  

  

  energetics 
  of 
  the 
  problem. 
  On 
  the 
  assumption 
  that 
  the 
  depart- 
  

  

  T^ 
  

   ure 
  from 
  Ohms 
  law 
  is 
  not 
  large,* 
  since 
  C 
  = 
  — 
  and 
  the 
  

  

  R 
  

  

  amount 
  of 
  the 
  impedance 
  in 
  the 
  circuit 
  is 
  so 
  small 
  as 
  to 
  be 
  

   neglected, 
  we 
  shall 
  have 
  an 
  amount 
  of 
  energy 
  developed 
  in 
  the 
  

   tube 
  for 
  perhaps 
  the 
  millionth 
  part 
  of 
  a 
  second 
  equal 
  to 
  CE. 
  

   With 
  an 
  electromotive 
  force 
  of 
  10,000 
  volts 
  and 
  a 
  resistance 
  of 
  

   ten 
  ohms, 
  a 
  current 
  of 
  1,000 
  amperes 
  must 
  be 
  obtained, 
  and 
  

   this 
  multiplied 
  by 
  10,000 
  and 
  divided 
  by 
  746 
  gives 
  the 
  elec- 
  

   trical 
  horse 
  power 
  if 
  the 
  current 
  were 
  maintained 
  for 
  a 
  second. 
  

   The 
  corresponding 
  value 
  is 
  over 
  ten 
  thousand, 
  and 
  this 
  corre- 
  

   sponds 
  to 
  an 
  excessively 
  high 
  temperature 
  for 
  a 
  very 
  brief 
  

   space 
  of 
  time. 
  

  

  Of 
  course 
  a 
  bolometer 
  or 
  any 
  other 
  thermometer 
  in 
  the 
  tube 
  

   could 
  not 
  indicate 
  this 
  energy, 
  for 
  it 
  is 
  of 
  very 
  short 
  duration 
  

   and 
  even 
  in 
  its 
  brief 
  existence 
  undoubtedly 
  does 
  not 
  affect 
  the 
  

   whole 
  mass 
  of 
  the 
  gas 
  through 
  which 
  the 
  discharge 
  passes. 
  

   J. 
  J. 
  Thomson 
  has 
  called 
  attention 
  to 
  this 
  fact.f 
  In 
  the 
  case 
  

   of 
  the 
  continuous 
  discharge 
  the 
  temperature 
  is 
  undoubtedly 
  

   vastly 
  lower, 
  but 
  even 
  here 
  it 
  is 
  probable 
  that 
  the 
  pale 
  

   brush 
  does 
  not 
  concern 
  all 
  the 
  particles 
  of 
  the 
  rarified 
  gas. 
  

  

  * 
  Moreover 
  we 
  find 
  that 
  the 
  electrostatic 
  capacity 
  of 
  the 
  Geissler 
  tube 
  is 
  not 
  

   sufficient 
  to 
  affect 
  the 
  period 
  of 
  the 
  oscillatory 
  movement. 
  To 
  decide 
  this 
  we 
  

   arranged 
  a 
  rocking 
  key 
  which 
  interposed 
  first 
  the 
  Geissler 
  tube 
  and 
  then 
  imme- 
  

   diately 
  afterward 
  a 
  wire 
  of 
  self-induction 
  equal 
  to 
  that 
  of 
  the 
  tube, 
  and 
  photo- 
  

   graphed 
  the 
  oscillatory 
  discharge 
  through 
  the 
  two 
  circuits. 
  No 
  change 
  could 
  be 
  

   perceived 
  in 
  the 
  period 
  of 
  the 
  two 
  discharges. 
  If 
  the 
  electrostatic 
  capacity 
  of 
  a 
  

   Geissler 
  tube 
  were 
  large 
  an 
  argon 
  tube 
  would 
  not 
  be 
  as 
  sensitive 
  as 
  it 
  is 
  to 
  slight 
  

   changes 
  in 
  electrostatic 
  capacity 
  in 
  the 
  circuit. 
  

  

  f 
  Recent 
  researches, 
  p. 
  167. 
  

  

  