﻿Spectra 
  of 
  Iodine 
  under 
  High 
  Dispersion. 
  841 
  

  

  two 
  components 
  of 
  the 
  doublet 
  about 
  the 
  same, 
  which 
  is 
  what 
  

   we 
  should 
  expect. 
  

  

  Line 
  No. 
  3 
  first 
  appears 
  when 
  the 
  voltage 
  of 
  the 
  lamp 
  is 
  

   110, 
  when 
  it 
  is 
  much 
  fainter 
  than 
  line 
  "2. 
  At 
  125 
  volts 
  

   lines 
  2 
  and 
  3 
  have 
  the 
  same 
  intensity, 
  while 
  at 
  140 
  volts 
  3 
  is 
  

   much 
  stronger 
  than 
  2. 
  Line 
  3 
  is 
  removed 
  by 
  bromine 
  

   filtration 
  of 
  the 
  exciting 
  light, 
  and 
  I 
  believe 
  that 
  it 
  is 
  a 
  

   companion 
  line 
  due 
  to 
  the 
  stimulation 
  of 
  absorption 
  line 
  7, 
  

   the 
  core 
  line 
  associated 
  with 
  it 
  lying 
  a 
  little 
  to 
  the 
  right 
  of 
  

   the 
  core 
  line 
  excited 
  by 
  absorption 
  lines 
  3 
  and 
  4. 
  

  

  The 
  difficulty 
  in 
  interpreting 
  the 
  results 
  obtained 
  is 
  due 
  to 
  

   the 
  fact 
  that 
  the 
  mercury 
  line 
  widens 
  both 
  to 
  the 
  right 
  and 
  

   left 
  as 
  the 
  voltage 
  increases, 
  so 
  that 
  two 
  absorption 
  lines 
  may 
  

   be 
  attacked 
  simultaneously. 
  If 
  this 
  happens, 
  we 
  can 
  differ- 
  

   entiate 
  between 
  them 
  only 
  if 
  one 
  of 
  them 
  is 
  in 
  coincidence 
  

   with 
  a 
  bromine 
  line 
  and 
  the 
  other 
  not. 
  What 
  is 
  most 
  needed 
  

   just 
  now 
  is 
  one 
  or 
  more 
  other 
  filters 
  similar 
  to 
  bromine 
  

   vapour, 
  but 
  I 
  have 
  not 
  been 
  able 
  to 
  find 
  anything 
  with 
  

   sufficiently 
  narrow 
  lines, 
  though 
  I 
  have 
  tried 
  a 
  number 
  of 
  

   vapours 
  which 
  looked 
  promising. 
  What 
  would 
  be 
  still 
  

   better 
  would 
  be 
  to 
  alter 
  the 
  wave-length 
  of 
  a 
  narrow 
  exciting 
  

   line 
  so 
  as 
  to 
  cause 
  it 
  to 
  pass 
  by 
  degrees 
  from 
  one 
  absorption 
  

   line 
  to 
  the 
  next. 
  It 
  may 
  be 
  possible 
  to 
  accomplish 
  this 
  by 
  

   admitting 
  hydrogen 
  to 
  the 
  Cooper-Hewitt 
  lamp, 
  though 
  I 
  

   fear 
  that 
  this 
  will 
  broaden 
  the 
  line 
  as 
  well 
  as 
  shift 
  it. 
  I 
  shall 
  

   try 
  putting 
  the 
  mercury 
  lamp 
  in 
  a 
  magnetic 
  field, 
  as 
  soon 
  as 
  

   a 
  Weiss 
  magnet 
  is 
  available. 
  

  

  If 
  we 
  examine 
  the 
  resonance 
  spectrum 
  as 
  a 
  whole, 
  we 
  find 
  

   that 
  it 
  is 
  made 
  up 
  of 
  groups 
  more 
  or 
  less 
  similar 
  to 
  the 
  

   groups 
  which 
  we 
  have 
  considered 
  somewhat 
  minutely, 
  and 
  

   fainter 
  groups 
  of 
  less 
  sharply 
  defined 
  lines 
  (hazy 
  triplets 
  

   such 
  as 
  the 
  2nd 
  and 
  4th 
  order 
  groups 
  of 
  the 
  90 
  volt 
  excitation 
  

   shown 
  in 
  fig. 
  2). 
  Their 
  arrangement 
  in 
  the 
  spectrum 
  is 
  

   worthy 
  of 
  remark, 
  for 
  we 
  find 
  the 
  arrangement 
  repeating 
  

   itself. 
  If 
  we 
  call 
  the 
  hazy 
  triplets 
  H, 
  and 
  the 
  groups 
  of 
  

   sharp 
  lines 
  S, 
  the 
  complete 
  spectrum 
  is 
  represented 
  thus 
  : 
  

  

  Order 
  -10 
  12 
  3 
  

   H 
  S 
  S 
  H 
  S 
  

  

  4 
  5 
  6 
  7 
  

   H 
  S 
  S 
  H 
  

  

  9 
  10 
  

  

  S 
  

  

  11 
  12 
  13 
  14 
  15 
  

   H 
  S 
  S 
  H 
  S 
  

  

  16 
  17 
  18 
  19 
  20 
  

   H 
  S 
  S 
  H 
  S 
  

  

  I 
  have 
  underscored 
  the 
  arrangement 
  which 
  repeats 
  itself 
  

   three 
  times 
  certainly, 
  and 
  probably 
  four 
  times, 
  though 
  there 
  

   is 
  doubt 
  about 
  groups 
  19 
  and 
  20. 
  The 
  sequence 
  is 
  inter- 
  

   rupted 
  at 
  the 
  9th 
  group, 
  which 
  is 
  missing. 
  

  

  We 
  will 
  now 
  consider 
  the 
  sharp 
  groups 
  which 
  appear 
  in 
  

   the 
  red 
  and 
  orange 
  part 
  of 
  the 
  spectrum. 
  As 
  we 
  have 
  seen, 
  

  

  