﻿416 
  Dr. 
  H. 
  E. 
  Ives 
  on 
  the 
  Resolution 
  of 
  Mixed 
  

  

  On 
  making 
  the 
  experiment 
  with 
  the 
  new 
  arrangement, 
  it 
  

   was 
  found 
  that 
  the 
  appearance 
  presented 
  was 
  unmistakably 
  

   that 
  of 
  fig. 
  1 
  b 
  — 
  that 
  is, 
  the 
  mixed 
  colour 
  when 
  passed 
  across 
  the 
  

   field 
  of 
  vision 
  teas 
  resolved 
  into 
  its 
  components, 
  just 
  as 
  it 
  would 
  

   have 
  been 
  if 
  viewed 
  through 
  a 
  weak 
  prism. 
  By 
  careful 
  

  

  Arrangement 
  of 
  Apparatus. 
  

  

  a, 
  box 
  containing 
  two 
  point-source 
  tungsten 
  lamps. 
  

  

  b, 
  resistance 
  for 
  controlling 
  current 
  through 
  lamps. 
  

  

  c, 
  c, 
  diaphragms. 
  

  

  d, 
  d, 
  coloured 
  glasses. 
  

  

  e, 
  matte 
  white 
  surface. 
  

   /, 
  slit. 
  

  

  rj, 
  mirror. 
  

  

  h, 
  observer's 
  eye. 
  

  

  j, 
  movable 
  screens 
  of 
  short 
  vertical 
  length. 
  

  

  h, 
  monochromatic 
  illuminator. 
  

  

  Z, 
  opal 
  glass. 
  

  

  adjustment 
  of 
  the 
  intensities 
  the 
  effect 
  was 
  made 
  so 
  clear-cut 
  

   as 
  to 
  be 
  immediately 
  apparent, 
  and 
  was 
  verified 
  by 
  a 
  number 
  

   of 
  observers. 
  This 
  effect 
  is 
  shown 
  very 
  strikingly 
  if 
  the 
  

   slit 
  image 
  is 
  oscillated 
  by 
  the 
  proper 
  mirror 
  movement. 
  In 
  

   this 
  case 
  the 
  two 
  colours 
  appear 
  to 
  slide 
  over 
  each 
  other 
  at 
  

   their 
  overlapping 
  portion. 
  The 
  appearance 
  here 
  is 
  as 
  though 
  

   a 
  purple 
  slit 
  of 
  moderate 
  length 
  were 
  viewed 
  through 
  a 
  prism 
  

   set 
  with 
  its 
  edge 
  at 
  right 
  angles 
  to 
  the 
  direction 
  of 
  the 
  slit, 
  

   and 
  then 
  rotated 
  back 
  and 
  forth 
  with 
  the 
  line 
  of 
  sight 
  as 
  

   an 
  axis. 
  

  

  