﻿254 
  

  

  Profs. 
  Wood 
  and 
  Kimura 
  on 
  the 
  

  

  From 
  this 
  point 
  on 
  values 
  determined 
  from 
  plates 
  made 
  

   with 
  telescope 
  of 
  1 
  metre 
  focus. 
  They 
  are 
  correct 
  only 
  to 
  

   about 
  O'l 
  AIL 
  

  

  18 
  

  

  . 
  6618-63 
  

   6820-01 
  

  

  146657 
  

   146608 
  

  

  49 
  

  

  146636 
  

  

  +21 
  

  

  19.... 
  

  

  . 
  Faint 
  and 
  masked 
  

  

  by 
  mercury 
  

  

  Line 
  

  

  

  

  20.... 
  

  

  . 
  6998-96 
  

   7001-39 
  

  

  142878 
  

   142828 
  

  

  50 
  

  

  142842 
  

  

  +36 
  

  

  21.... 
  

  

  . 
  Missing 
  

  

  

  

  

  

  22.... 
  

  

  . 
  718623 
  

  

  7188-68 
  

  

  139155 
  

   139107 
  

  

  48 
  

  

  139099 
  

  

  +56 
  

  

  23.... 
  

  

  .. 
  7282-39 
  

   7284-92 
  

  

  137318 
  

   137270 
  

  

  48 
  

  

  137247 
  

  

  +71 
  

  

  24.... 
  

  

  . 
  . 
  Missing 
  

  

  

  

  

  

  25.... 
  

  

  .. 
  7480-4 
  

   7482-9 
  

  

  133682 
  

   133638 
  

  

  44 
  

  

  133580 
  

  

  +102 
  

  

  26.... 
  

  

  .. 
  Missing 
  

  

  

  

  

  

  27.... 
  

  

  .. 
  7685-7 
  

   7688-5 
  

  

  130110 
  

   130060 
  

  

  50 
  

  

  129964 
  

  

  +146 
  

  

  The 
  first 
  point 
  established 
  by 
  this 
  table 
  is 
  that, 
  while 
  the 
  

   separation 
  of 
  the 
  components 
  of 
  the 
  doublets 
  increases 
  pro- 
  

   gressively 
  from 
  1*51 
  AU. 
  at 
  order 
  to 
  2'5 
  AU. 
  at 
  the 
  twenty- 
  

   seventh 
  order, 
  the 
  frequency 
  difference 
  between 
  the 
  

   components 
  is 
  A 
  constant, 
  50. 
  The 
  extreme 
  low 
  values 
  

   46 
  and 
  44 
  found 
  in 
  the 
  sixteenth 
  and 
  twenty-fifth 
  orders 
  

   are 
  undoubtedly 
  due 
  to 
  the 
  fact 
  that 
  the 
  lines 
  were 
  extremely 
  

   faint, 
  and 
  the 
  wave-lengths 
  could 
  not 
  be 
  very 
  accurately 
  

   determined. 
  The 
  last 
  doublet 
  (the 
  twenty-seventh 
  order) 
  

   was 
  fairly 
  strong, 
  and 
  the 
  frequency 
  difference 
  in 
  this 
  case 
  

   is 
  exactly 
  the 
  same 
  as 
  in 
  the 
  case 
  of 
  the 
  order. 
  

  

  We 
  will 
  now 
  consider 
  the 
  law 
  governing 
  the 
  spacing 
  of 
  

   the 
  doublets 
  along 
  the 
  spectrum, 
  applying 
  the 
  calculations 
  

   to 
  the 
  first 
  member 
  of 
  each 
  doublet 
  (shorter 
  \ 
  component). 
  

   If 
  we 
  confine 
  our 
  attention 
  to 
  the 
  first 
  few 
  orders, 
  it 
  seems 
  

   as 
  if 
  the 
  distance 
  between 
  the 
  doublets 
  increased 
  by 
  a 
  con- 
  

   stant 
  small 
  increment. 
  This 
  would 
  mean 
  a 
  constant 
  second 
  

   difference 
  of 
  wave-lengths. 
  It 
  was 
  found, 
  however, 
  that 
  this 
  

   condition 
  held 
  only 
  for 
  the 
  first 
  few 
  orders. 
  The 
  reciprocals 
  

   of 
  the 
  wave-lengths 
  were 
  next 
  examined, 
  and 
  it 
  was 
  found 
  

   that 
  a 
  constant 
  second 
  difference 
  existed, 
  at 
  least 
  over 
  a 
  

   considerable 
  range 
  of 
  the 
  spectrum. 
  

  

  