﻿the 
  Echelon 
  Spectroscope. 
  

  

  393 
  

  

  Table 
  III. 
  — 
  Measurements 
  of 
  the 
  Green 
  Mercury-line 
  

   Spectrum 
  [continued). 
  

  

  Nagaoka. 
  

  

  Author. 
  

  

  Eeference 
  

   Numbers. 
  

  

  Echelon 
  

   Spectro3Cope. 
  

  

  Primary 
  

   Spectrum. 
  

  

  Secondary 
  Point 
  

   Spectrum. 
  

  

  Width. 
  

  

  

   31 
  

   72 
  

  

  105 
  

   137 
  

   163 
  

   189 
  

  

  

  

  135 
  

   164 
  

  

  ... 
  

  

  

  

  141 
  

   167 
  

  

  17 
  

  

  13 
  

  

  13 
  

  

  1 
  

  

  2 
  

   3 
  

  

  223 
  

  

  247 
  

  

  J 
  (217) 
  

  

  22? 
  1 
  (^) 
  

  

  217 
  

   243 
  

  

  16 
  

  

  24 
  

  

  ^ 
  ) 
  Central 
  

   5 
  1 
  Band. 
  

  

  280 
  

   315 
  

   356 
  

   390 
  

   448 
  

   477 
  

  

  319 
  

   363 
  

  

  448 
  

  

  322 
  

   365 
  

  

  17 
  

   12 
  

  

  14 
  

  

  6 
  

  

  7 
  

  

  8 
  

  

  Fabry 
  and 
  Perot^s 
  values* 
  given 
  in 
  the 
  Table 
  are 
  those 
  

   published 
  by 
  Zeemanf 
  in 
  1902. 
  They 
  help 
  to 
  confirm 
  

   the 
  accuracy 
  of 
  the 
  constants 
  employed 
  in 
  the 
  echelon 
  

   calculations. 
  

  

  The 
  results 
  obtained 
  by 
  several 
  other 
  observers 
  are 
  given 
  

   by 
  JanickiJ. 
  

  

  The 
  series 
  of 
  faint 
  lines 
  given 
  by 
  ]N^aoaoka 
  resembles 
  the 
  

   series 
  of 
  false 
  lines 
  in 
  my 
  primary 
  echelon 
  photographs. 
  

   I 
  published 
  my 
  measurements 
  for 
  comparison 
  with 
  his 
  before 
  

   discovering 
  that 
  the 
  faint 
  lines 
  in 
  my 
  photographs 
  were 
  not 
  

   genuine 
  §. 
  

  

  * 
  M. 
  Perot 
  informs 
  me 
  (in 
  a 
  letter 
  dated 
  Oct. 
  13th, 
  1908) 
  that 
  they 
  

   have 
  not 
  published 
  any 
  particulars 
  of 
  this 
  line 
  since 
  then, 
  

   t 
  Astrophysical 
  Journal, 
  xv. 
  p. 
  218 
  (1902). 
  

   "^ 
  Loc, 
  cit. 
  p. 
  61. 
  

   5 
  * 
  Nature,' 
  vol. 
  Ixxviii. 
  p. 
  8 
  (1908). 
  

  

  