﻿Rood 
  — 
  Color-vision 
  and 
  the 
  Flicker 
  Photometer. 
  259 
  

  

  calculations, 
  without 
  the 
  aid 
  of 
  supplementary 
  experiments 
  of 
  

   a 
  totally 
  different 
  character. 
  This 
  much 
  being 
  premised, 
  the 
  

   tables 
  given 
  below 
  will 
  be 
  intelligible. 
  Classes 
  A 
  and 
  B 
  are 
  

   given 
  separately 
  for 
  the 
  convenience 
  of 
  the 
  reader, 
  though 
  as 
  

   before 
  said 
  I 
  do 
  not 
  know 
  of 
  any 
  reason 
  for 
  giving 
  preference 
  

   to 
  one 
  over 
  the 
  other 
  ; 
  indeed 
  it 
  will 
  be 
  noticed 
  that 
  they 
  are 
  

   more 
  or 
  less 
  blended 
  together 
  by 
  the 
  cases 
  of 
  Wade, 
  Parker 
  

   and 
  White. 
  

  

  Class 
  A. 
  

  

  Red. 
  Green. 
  Violet 
  blue. 
  

  

  Wade 
  97-7 
  97-4 
  100- 
  

  

  Trowbridge 
  100- 
  91-6 
  . 
  95-6 
  

  

  Dr. 
  Hallock 
  100- 
  90-9 
  96*2 
  

  

  Miss 
  Furness 
  97*9 
  90*8 
  100- 
  

  

  Curtis.-- 
  90-5 
  86-6 
  100' 
  

  

  MissM.. 
  100- 
  81-6 
  99- 
  

  

  Class 
  B. 
  

  

  Red. 
  Green. 
  Violet 
  blue. 
  

  

  White 
  --- 
  96-1 
  100 
  95-8 
  

  

  Parker 
  95'7 
  100 
  95-8 
  

  

  Dr. 
  Dennett 
  93-8 
  100 
  91-5 
  

  

  Dr. 
  Tufts 
  89-9 
  100 
  87-8 
  

  

  Dr. 
  Day_. 
  82'9 
  100 
  93-3 
  

  

  It 
  may 
  be 
  remarked 
  that 
  all 
  the 
  persons 
  above 
  mentioned 
  

   are 
  unusually 
  abstemious 
  in 
  the 
  use 
  of 
  alcohol, 
  tea, 
  coffee, 
  and 
  

   tobacco, 
  and 
  the 
  person 
  who 
  is 
  most 
  deficient 
  in 
  red 
  does 
  not 
  

   use 
  these 
  articles 
  at 
  all. 
  

  

  It 
  is 
  true 
  that 
  the 
  above 
  results 
  have 
  been 
  obtained 
  by 
  the 
  

   aid 
  of 
  a 
  standard 
  derived 
  from 
  only 
  eleven 
  persons, 
  all, 
  appar- 
  

   ently, 
  with 
  what 
  has 
  heretofore 
  been 
  called 
  normal 
  vision 
  : 
  of 
  

   course 
  it 
  would 
  be 
  desirable 
  to 
  extend 
  the 
  observations 
  to 
  a 
  

   larger 
  number 
  of 
  persons, 
  but 
  in 
  the 
  meanwhile 
  it 
  is 
  quite 
  evi- 
  

   dent 
  that 
  the 
  standard 
  here 
  adopted 
  is 
  considerably 
  better 
  than 
  

   if 
  one 
  of 
  the 
  eleven 
  had 
  been 
  selected, 
  hap-hazard, 
  as 
  a 
  repre- 
  

   sentative 
  of 
  normal 
  vision. 
  It 
  also 
  follows 
  that 
  anyone 
  of 
  the 
  

   eleven, 
  when 
  furnished 
  with 
  his 
  curve, 
  becomes 
  a 
  secondary 
  

   standard, 
  and 
  can 
  correct 
  his 
  observations 
  till 
  they 
  are 
  in 
  accord 
  

   with 
  the 
  standard 
  here 
  adopted. 
  These 
  results 
  also 
  make 
  it 
  

   evident, 
  that 
  no 
  one, 
  man 
  or 
  woman, 
  is 
  qualified 
  to 
  do 
  reliable 
  

   quantitative 
  color-work 
  until 
  his 
  or 
  her 
  color-vision 
  has 
  been 
  

   tested 
  as 
  above 
  indicated. 
  Certain 
  discrepancies 
  in 
  the 
  older 
  

   determinations 
  may 
  find 
  here 
  a 
  partial 
  explanation, 
  the 
  remain- 
  

   der, 
  of 
  course, 
  being 
  due 
  to 
  the 
  employment 
  of 
  the 
  older 
  

   photometric 
  methods. 
  

  

  Below 
  are 
  the 
  results 
  for 
  three 
  cases 
  of 
  red 
  color-blindness, 
  

  

  