﻿Trowbridge 
  and 
  Richards 
  — 
  Temperature, 
  etc. 
  327 
  

  

  Art. 
  XXXI. 
  — 
  The 
  Temperature 
  and 
  Ohmic 
  Resistance 
  of 
  

   Gases 
  during 
  the 
  Oscillatory 
  Electric 
  Discharge 
  ; 
  by 
  John 
  

   Trowbridge 
  and 
  Theodore 
  Wm. 
  Kichaeds. 
  With 
  Plate 
  

   VI. 
  

  

  Ix 
  our 
  papers 
  upon 
  the 
  spectra 
  of 
  argon 
  and 
  the 
  multiple 
  

   spectra 
  of 
  gases,* 
  we 
  have 
  emphasized 
  the 
  importance 
  of 
  con- 
  

   sidering 
  the 
  electrical 
  condition 
  of 
  the 
  circuit 
  in 
  which 
  is 
  

   placed 
  the 
  Pliicker 
  tube 
  containing 
  the 
  gas 
  under 
  examination. 
  

   We 
  have 
  pointed 
  anew 
  to 
  the 
  fact 
  that 
  in 
  general 
  the 
  continu- 
  

   ous 
  discharge 
  of 
  an 
  accumulator 
  produces 
  one 
  spectrum 
  while 
  

   the 
  oscillatory 
  discharge 
  of 
  a 
  condenser 
  produces 
  another. 
  In 
  

   considering 
  this 
  question 
  one 
  is 
  immediately 
  struck 
  by 
  the 
  fact 
  

   that, 
  although 
  the 
  gas 
  acts 
  as 
  if 
  it 
  presented 
  a 
  resistance 
  of 
  

   several 
  hundred 
  thousand 
  or 
  even 
  several 
  million 
  ohms 
  to 
  the 
  

   current 
  while 
  under 
  the 
  influence 
  of 
  the 
  continuous 
  discharge, 
  

   nevertheless 
  this 
  same 
  tube 
  allows 
  oscillations 
  which 
  are 
  wholly 
  

   damped 
  by 
  a 
  few 
  hundred 
  ohms 
  to 
  pass 
  through 
  it 
  under 
  the 
  

   influence 
  of 
  a 
  condenser. 
  These 
  considerations 
  led 
  us 
  to 
  

   measure 
  the 
  resistance 
  of 
  such 
  a 
  tube 
  to 
  the 
  oscillatory 
  dis- 
  

   charge, 
  and 
  we 
  found 
  by 
  means 
  of 
  a 
  novel 
  method 
  that 
  in 
  fact 
  

   a 
  mass 
  of 
  gas 
  at 
  low 
  tension 
  contained 
  in 
  a 
  capillary 
  tube 
  may 
  

   act 
  as 
  though 
  it 
  opposed 
  a 
  resistance 
  of 
  only 
  five 
  or 
  six 
  ohms 
  

   to 
  the 
  spark 
  of 
  a 
  large 
  condenser. 
  

  

  In 
  order 
  the 
  more 
  clearly 
  to 
  grasp 
  the 
  situation, 
  the 
  poten- 
  

   tial 
  differences 
  between 
  the 
  ends 
  of 
  the 
  tube 
  during 
  a 
  con- 
  

   tinuous 
  discharge 
  may 
  well 
  be 
  considered 
  first. 
  A 
  number 
  

   of 
  measurements 
  of 
  such 
  potential 
  differences 
  have 
  been 
  made 
  

   by 
  Hittorf-f 
  and 
  others, 
  but 
  it 
  may 
  be 
  well 
  to 
  give 
  two 
  of 
  the 
  

   many 
  series 
  of 
  measurements 
  which 
  we 
  have 
  made, 
  in 
  order 
  

   to 
  facilitate 
  comparison 
  with 
  the 
  discharge 
  of 
  the 
  condenser 
  

   through 
  the 
  same 
  tubes. 
  The 
  tubes 
  employed 
  throughout 
  this 
  

   research 
  were 
  of 
  the 
  ordinary 
  type 
  devised 
  by 
  Pliicker, 
  con- 
  

   sisting 
  of 
  two 
  cylindrical 
  bulbs 
  separated 
  by 
  a 
  capillary 
  l 
  - 
  3 
  mm 
  

   in 
  diameter 
  and 
  T 
  cm 
  long. 
  The 
  electrodes 
  were 
  of 
  aluminum. 
  

   Unless 
  otherwise 
  stated, 
  all 
  the 
  experiments 
  here 
  recorded 
  

   were 
  made 
  with 
  tubes 
  of 
  exactly 
  this 
  shape 
  and 
  size 
  ; 
  and 
  

   most 
  of 
  the 
  experiments 
  were 
  made 
  with 
  a 
  single 
  tube. 
  The 
  

   voltmeter 
  used 
  for 
  measuring 
  the 
  potential 
  differences 
  was 
  a 
  

   Thomson 
  electrostatic 
  electrometer, 
  and 
  the 
  current 
  used 
  was 
  

   not 
  much 
  over 
  a 
  milliampere. 
  

  

  As 
  the 
  voltmeter 
  was 
  only 
  graduated 
  to 
  1S00 
  volts, 
  the 
  

   readings 
  above 
  that 
  amount 
  are 
  merely 
  approximations. 
  

  

  *This 
  Journal, 
  vol. 
  iii, 
  pp. 
  15 
  and 
  117, 
  1897. 
  

   f 
  Wied. 
  Ann., 
  xx, 
  705. 
  

  

  