﻿810 
  

  

  Prof. 
  E. 
  W. 
  Wood 
  on 
  Resonance 
  

  

  forms 
  tlie 
  element 
  of 
  the 
  group 
  is 
  given 
  on 
  the 
  right, 
  thus 
  

   absorption 
  line 
  No. 
  3 
  gives 
  us 
  the 
  core 
  line 
  No. 
  5 
  and 
  the 
  

   companion 
  line 
  No. 
  6. 
  

  

  Fig. 
  3. 
  

  

  / 
  s/ 
  ~0/-tfer 
  Group- 
  

  

  is* 
  'Order 
  Group 
  

  

  Cooper 
  

  

  Hewitt 
  | 
  

  

  i 
  i 
  

  

  

  , 
  , 
  

  

  46 
  Volts 
  , 
  

  

  

  

  60 
  Volts 
  | 
  | 
  

  

  | 
  

  

  90 
  Volts 
  

  

  .1 
  

  

  

  

  DO 
  Volts 
  | 
  ||| 
  

  

  \ 
  i 
  

  

  mvoits 
  

  

  l 
  1 
  

  

  II 
  i 
  1 
  

  

  140 
  Volts 
  i 
  

  

  1 
  fill 
  hi 
  i,i 
  

  

  \ 
  ^ 
  5 
  4 
  5 
  6783 
  

  

  N°ofthe 
  

  

  

   3 
  

  

  4 
  

  

  2 
  

   5 
  

   6 
  

   7 
  

  

  i 
  

  

  j4Q 
  Volts 
  

  

  Bromine 
  ' 
  

   Filter 
  i 
  

  

  4 
  5 
  6 
  

  

  In 
  the 
  case 
  of 
  the 
  Cooper-Hewitt 
  excitation 
  there 
  are 
  a 
  

   number 
  of 
  faint 
  companion 
  lines 
  which 
  do 
  not 
  appear 
  in 
  any 
  

   of 
  the 
  other 
  cases, 
  at 
  least 
  with 
  the 
  times 
  of 
  exposure 
  given. 
  

   This 
  may 
  result 
  from 
  the 
  circumstance 
  that 
  the 
  stronger 
  lines 
  

   are 
  more 
  weakened 
  by 
  absorption, 
  which 
  plays 
  a 
  prominent 
  

   part 
  in 
  this 
  type 
  of 
  excitation. 
  With 
  the 
  quartz 
  arc 
  at 
  

   46 
  volts 
  we 
  have 
  the 
  core 
  line 
  5, 
  and 
  the 
  companions 
  2 
  and 
  6. 
  

   At 
  60 
  volts 
  a 
  companion 
  appears 
  to 
  the 
  left 
  of 
  the 
  core 
  line. 
  

   I 
  think 
  that 
  this 
  results 
  from 
  the 
  stimulation 
  of 
  absorption 
  

   line 
  No. 
  2, 
  but 
  am 
  not 
  quite 
  sure. 
  At 
  90 
  volts 
  line 
  4, 
  a 
  close 
  

   doublet, 
  first 
  appears. 
  It 
  is 
  quite 
  certain 
  that 
  this 
  doublet 
  

   results 
  from 
  the 
  stimulation 
  of 
  two 
  iodine 
  absorption 
  lines, 
  

   since 
  if 
  the 
  exciting 
  light 
  is 
  filtered 
  through 
  bromine, 
  the 
  

   right-hand 
  component 
  of 
  the 
  doublet 
  disappears, 
  consequently 
  

   the 
  left-hand 
  component 
  must 
  be 
  excited 
  by 
  an 
  iodine 
  ab- 
  

   sorption 
  line 
  which 
  is 
  not 
  in 
  coincidence 
  with 
  a 
  bromine 
  line, 
  

   and 
  which 
  is 
  first 
  covered 
  by 
  the 
  mercury 
  line 
  when 
  the 
  

   lamp 
  is 
  at 
  90 
  volts. 
  This 
  seems 
  to 
  be 
  absorption 
  line 
  No. 
  5, 
  

   while 
  the 
  other 
  component, 
  which 
  is 
  removed 
  by 
  filtration 
  of 
  

   the 
  exciting 
  light 
  through 
  bromine, 
  is 
  probably 
  due 
  to 
  ab- 
  

   sorption 
  line 
  6. 
  In 
  the 
  third 
  order 
  group 
  this 
  doublet 
  

   appears 
  in 
  the 
  same 
  place, 
  but 
  with 
  its 
  right-hand 
  component 
  

   of 
  about 
  three 
  times 
  the 
  intensity 
  of 
  the 
  left 
  : 
  bromine 
  

   filtration 
  of 
  the 
  exciting 
  light 
  makes 
  the 
  intensities 
  of 
  the 
  

  

  