﻿Resistance 
  of 
  Gases 
  during 
  an 
  Oscillatory 
  Discharge. 
  341 
  

  

  gen 
  atoms, 
  and 
  that 
  these 
  atoms, 
  or 
  perhaps 
  the 
  energy 
  

   involved 
  in 
  the 
  act 
  of 
  splitting 
  them, 
  are 
  responsible 
  for 
  the 
  

   "four 
  line" 
  red 
  spectrum. 
  The 
  fact 
  cannot 
  be 
  too 
  strongly 
  

   emphasized 
  that 
  this 
  sort 
  of 
  dissociation 
  is 
  very 
  different 
  indeed 
  

   from 
  the 
  electrolytic 
  dissociation 
  of 
  solutions. 
  

  

  In 
  order 
  to 
  find 
  if 
  the 
  structure 
  which 
  is 
  dissociated 
  by 
  the 
  

   spark 
  is 
  the 
  molecule 
  or 
  some 
  more 
  complex 
  structure, 
  mer- 
  

   cury 
  vapor 
  was 
  subjected 
  first 
  to 
  the 
  continuous 
  discharge 
  and 
  

   then 
  to 
  the 
  oscillatory. 
  Since 
  the 
  spectra 
  obtained 
  were 
  widely 
  

   different, 
  the 
  conclusion, 
  at 
  least 
  in 
  the 
  case 
  of 
  the 
  mercury, 
  is 
  

   that 
  the 
  structure 
  is 
  complex 
  ; 
  for 
  mercury 
  molecules 
  are 
  mona- 
  

   tomic. 
  This 
  conclusion 
  is 
  reinforced 
  by 
  many 
  other 
  facts 
  

   known 
  about 
  the 
  continuous 
  discharge. 
  Hence 
  the 
  existence 
  

   of 
  two 
  argon 
  spectra 
  does 
  not 
  give 
  any 
  reason 
  for 
  disbelieving 
  

   the 
  evidence 
  of 
  specific 
  heat 
  with 
  regard 
  to 
  the 
  monatomic 
  

   nature 
  of 
  argon. 
  

  

  From 
  the 
  point 
  of 
  view 
  of 
  a 
  mechanical 
  conception 
  of 
  the 
  

   causes 
  producing 
  the 
  two 
  spectra 
  of 
  a 
  gas, 
  it 
  is 
  easy 
  to 
  imagine 
  

   that 
  when 
  the 
  atoms 
  are 
  bound 
  together 
  in 
  the 
  polarized 
  con- 
  

   dition, 
  the 
  electricity 
  by 
  a 
  succession 
  of 
  readjustments 
  may 
  

   travel 
  step 
  by 
  step 
  from 
  one 
  end 
  of 
  the 
  tube 
  to 
  the 
  other, 
  at 
  a 
  

   comparatively 
  low 
  temperature, 
  and 
  so 
  cause 
  quite 
  a 
  different 
  

   set 
  of 
  electro-magnetic 
  vibrations 
  from 
  those 
  depending 
  upon 
  

   the 
  breaking 
  down 
  of 
  this 
  polarized 
  system. 
  The 
  evidence 
  

   that 
  the 
  second 
  spectrum 
  given 
  by 
  the 
  oscillatory 
  discharge 
  is 
  

   due 
  either 
  to 
  the 
  act 
  of 
  separating 
  the 
  atoms 
  from 
  one 
  another, 
  

   or 
  to 
  the 
  passage 
  of 
  the 
  electricity 
  through 
  the 
  atoms 
  already 
  

   set 
  free 
  by 
  the 
  heat, 
  has 
  been 
  given 
  above. 
  Hittorf's 
  experi- 
  

   ments, 
  in 
  which 
  he 
  was 
  able 
  to 
  send 
  a 
  very 
  strong 
  continuous 
  

   current 
  through 
  a 
  gas 
  without 
  the 
  production 
  of 
  light, 
  would 
  

   seem 
  to 
  indicate 
  that 
  the 
  light 
  is 
  due 
  to 
  energy 
  involved 
  at 
  the 
  

   moment 
  of 
  dissociation, 
  but 
  the 
  spectra 
  of 
  the 
  solar 
  promi- 
  

   nences 
  lead 
  to 
  the 
  opposite 
  inference, 
  and 
  conclusive 
  evidence 
  

   upon 
  this 
  point 
  is 
  wanting. 
  The 
  dissimilar 
  behavior 
  of 
  dif- 
  

   ferent 
  gases 
  is 
  easily 
  accounted 
  for 
  by 
  considering 
  the 
  two 
  

   causes 
  which 
  are 
  suj^posed 
  to 
  resist 
  the 
  dissociation 
  : 
  in 
  the 
  

   first 
  place, 
  the 
  " 
  polarized 
  " 
  condition 
  of 
  the 
  molecules, 
  and 
  in 
  

   the 
  next 
  place 
  the 
  chemical 
  affinity 
  of 
  the 
  atoms 
  for 
  one 
  

   another. 
  This 
  last 
  force 
  is 
  usually 
  admitted 
  to 
  be 
  greater 
  in 
  

   the 
  case 
  of 
  nitrogen 
  than 
  in 
  that 
  of 
  hydrogen, 
  hence 
  the 
  diffi- 
  

   culty, 
  the 
  irregularity 
  and 
  the 
  abruptness 
  of 
  the 
  transition 
  in 
  

   the 
  former 
  case. 
  One 
  should 
  expect 
  that 
  a 
  monatomic 
  gas, 
  

   like 
  argon, 
  where 
  the 
  polarization 
  alpne 
  prevents 
  the 
  passage 
  

   of 
  the 
  current, 
  would 
  be 
  easier 
  to 
  change 
  in 
  this 
  respect, 
  as 
  

   indeed 
  it 
  is. 
  The 
  fact 
  that 
  the 
  second 
  spectrum 
  of 
  mercury 
  is 
  

   not 
  very 
  easily 
  obtained, 
  militates 
  against 
  this 
  explanation, 
  

   however. 
  

  

  