﻿340 
  Trowbridge 
  and 
  Richards 
  — 
  Temperature 
  and 
  

  

  Therefore 
  calculations 
  or 
  experimental 
  determinations 
  of 
  the 
  

   average 
  temperature 
  of 
  a 
  large 
  tube, 
  such 
  as 
  those 
  of 
  Warburg* 
  

   and 
  Wood, 
  while 
  interesting 
  as 
  relative 
  considerations, 
  give 
  no 
  

   clue 
  as 
  to 
  the 
  kinetic 
  energy 
  of 
  the 
  molecules 
  which 
  actually 
  

   carry 
  the 
  current. 
  For 
  such 
  a 
  clue 
  one 
  must 
  refer 
  to 
  experi- 
  

   ments 
  of 
  the 
  sort 
  we 
  describe. 
  

  

  All 
  the 
  results 
  recorded 
  in 
  this 
  paper 
  support 
  the 
  well 
  

   known 
  hypothesis 
  that 
  the 
  current 
  when 
  disruptive 
  is 
  carried 
  

   by 
  dissociated 
  molecules. 
  The 
  continuous 
  discharge 
  is 
  best 
  

   explained 
  by 
  conceiving 
  of 
  a 
  polarized 
  condition, 
  in 
  which 
  the 
  

   molecules 
  are 
  in 
  some 
  way 
  bound 
  together 
  by 
  the 
  electric 
  

   energy 
  which 
  is 
  striving 
  to 
  force 
  itself 
  through 
  them. 
  As 
  the 
  

   current 
  increases, 
  the 
  amount 
  of 
  the 
  heat 
  increases, 
  until 
  it 
  

   reaches 
  a 
  stage 
  when 
  some 
  of 
  the 
  gas 
  is 
  freed 
  from 
  this 
  bond- 
  

   age 
  — 
  when 
  the 
  molecules 
  not 
  only 
  separate 
  from 
  their 
  electric 
  

   embrace, 
  but 
  split 
  into 
  their 
  component 
  atoms. 
  Then, 
  if 
  a 
  

   large 
  quantity 
  of 
  electricity 
  is 
  at 
  hand 
  to 
  discharge 
  itself, 
  the 
  

   rate 
  of 
  discharge 
  increases 
  with 
  enormous 
  rapidity, 
  resulting 
  

   in 
  more 
  dissociation, 
  and 
  the 
  resistance 
  is 
  almost 
  entirely 
  

   broken 
  down. 
  A 
  good 
  resume 
  of 
  the 
  present 
  state 
  of 
  this 
  

   hypothesis 
  is 
  given 
  in 
  Nature, 
  Jan. 
  28, 
  1897, 
  p. 
  310, 
  and 
  to 
  

   this 
  statement 
  our 
  determination 
  of 
  the 
  resistance 
  makes 
  an 
  

   important 
  addition. 
  

  

  Hydrogen 
  and 
  oxygen 
  cannot 
  be 
  dissociated 
  to 
  any 
  appre- 
  

   ciable 
  extent 
  at 
  ordinary 
  temperatures 
  and 
  pressures, 
  other- 
  

   wise 
  water 
  would 
  form 
  when 
  they 
  were 
  mixed. 
  We 
  have 
  no 
  

   vapor 
  densities 
  of 
  hydrogen 
  or 
  oxygen 
  at 
  temperatures 
  which 
  

   show 
  dissociation, 
  but 
  this 
  is 
  no 
  reason 
  for 
  believing 
  that 
  at 
  

   temperatures 
  of 
  three 
  thousand 
  degrees 
  or 
  more 
  dissociation 
  

   does 
  not 
  take 
  place. 
  Indeed, 
  the 
  burning 
  of 
  hydrogen 
  and 
  

   oxygen 
  gives 
  us 
  every 
  reason 
  for 
  believing 
  that 
  the 
  tendency 
  

   of 
  both 
  hydrogen 
  and 
  oxygen 
  molecules 
  to 
  dissociate 
  increases 
  

   with 
  the 
  temperature. 
  Chlorine, 
  bromine, 
  and 
  iodine 
  are 
  all 
  

   known 
  to 
  dissociate 
  at 
  high 
  temperatures, 
  and 
  to 
  conduct 
  elec- 
  

   tricity 
  well 
  under 
  those 
  conditions. 
  

  

  Another 
  point 
  in 
  favor 
  of 
  ascribing 
  the 
  red 
  glow 
  of 
  hydro- 
  

   gen 
  to 
  dissociation 
  is 
  to 
  be 
  found 
  in 
  the 
  fact 
  that 
  rarified 
  

   aqueous 
  vapor 
  gives 
  the 
  pure 
  " 
  four-line 
  " 
  spectrum 
  much 
  more 
  

   easily 
  than 
  hydrogen 
  itself. 
  In 
  order 
  to 
  give 
  any 
  hydrogen 
  

   spectrum 
  at 
  all, 
  the 
  vapor 
  must 
  be 
  dissociated. 
  Of 
  course 
  the 
  

   dissociation 
  takes 
  place 
  only 
  at 
  the 
  moment 
  of 
  the 
  discharge, 
  

   the 
  atoms 
  combining 
  again 
  when 
  cold. 
  It 
  is 
  caused 
  by 
  the 
  

   heat 
  of 
  the 
  discharge, 
  and 
  not 
  by 
  electrolysis, 
  although 
  that 
  

   too 
  may 
  take 
  place 
  at 
  the 
  electrodes. 
  In 
  short, 
  there 
  is 
  every 
  

   reason 
  to 
  believe 
  that 
  at 
  temperatures 
  as 
  high 
  as 
  those 
  with 
  

   which 
  we 
  are 
  dealing, 
  the 
  hydrogen 
  is 
  split 
  apart 
  into 
  hydro- 
  

  

  * 
  Wied. 
  Ann., 
  liv, 
  265. 
  

  

  