﻿of 
  the 
  Direction 
  of 
  Sounds. 
  319 
  

  

  of 
  the 
  sound 
  should 
  shift 
  unmistakably. 
  No 
  such 
  effect 
  

   could 
  be 
  detected. 
  

  

  So 
  far 
  we 
  have 
  discussed 
  only 
  the 
  simplest 
  case, 
  when 
  the 
  

   sounds 
  approach 
  through 
  tubes 
  and 
  impinge 
  only 
  on 
  the 
  

   ears. 
  But 
  if 
  the 
  theory 
  is 
  to 
  hold 
  for 
  the 
  practical 
  locating 
  

   of 
  sounds 
  in 
  the 
  open 
  air, 
  the 
  idea 
  of 
  interference 
  in 
  the 
  

   inner 
  ears 
  becomes 
  still 
  more 
  inadequate 
  to 
  account 
  for 
  the 
  

   facts. 
  Let 
  a 
  musical 
  note 
  be 
  struck 
  behind 
  a 
  person 
  and 
  at 
  

   an 
  angle 
  of 
  20° 
  with 
  the 
  medial 
  plane, 
  then 
  besides 
  the 
  sounds 
  

   travelling 
  through 
  the 
  head 
  from 
  one 
  ear 
  directly 
  to 
  the 
  

   other, 
  we 
  have 
  the 
  entire 
  back 
  part 
  of 
  the 
  head 
  struck 
  by 
  

   the 
  waves 
  of 
  sound. 
  These 
  waves 
  travel 
  through 
  the 
  head 
  

   to 
  the 
  inner 
  ears 
  with 
  different 
  lengths 
  of 
  paths, 
  at 
  varying 
  

   angles, 
  and 
  together 
  make 
  an 
  intensity 
  certainly 
  much 
  greater 
  

   than 
  the 
  waves 
  ^oing 
  from 
  one 
  ear 
  to 
  the 
  other. 
  It 
  would 
  

   be 
  extremely 
  difficult 
  to 
  predict 
  what 
  the 
  resultant 
  amplitude 
  

   would 
  be 
  when 
  all 
  these 
  motions 
  with 
  their 
  differing 
  phases 
  

   compounded 
  with 
  the 
  sound 
  entering 
  the 
  external 
  ear. 
  

   Locating 
  sounds 
  would 
  be 
  to 
  say 
  the 
  least 
  a 
  complicated 
  

   matter. 
  

  

  It 
  is 
  also 
  readily 
  understood 
  that 
  this 
  theory 
  would 
  lead 
  

   us 
  to 
  expect 
  that 
  simple 
  musical 
  tones 
  would 
  be 
  easier 
  to 
  

   locate 
  than 
  noises 
  which 
  have 
  not 
  so 
  simple 
  a 
  wave 
  form, 
  

   while 
  the 
  contrary 
  is 
  proved 
  by 
  experiment. 
  

  

  Xone 
  of 
  these 
  objections 
  applies 
  to 
  a 
  simple 
  and 
  direct 
  

   influence 
  of 
  phase 
  relations 
  on 
  our 
  hearing, 
  as 
  they 
  do 
  not 
  

   affect 
  the 
  phase 
  of 
  the 
  waves. 
  

  

  The 
  only 
  objection 
  to 
  the 
  idea 
  that 
  the 
  ear 
  is 
  capable 
  of 
  

   detecting 
  the 
  phase 
  of 
  a 
  sound 
  or 
  at 
  least 
  the 
  difference 
  

   between 
  the 
  phases 
  of 
  two 
  sounds, 
  is 
  that 
  it 
  is 
  difficult 
  to 
  

   reconcile 
  with 
  our 
  theories 
  of 
  audition. 
  But 
  is 
  it 
  not 
  a 
  fact 
  

   that 
  we 
  know 
  extremely 
  little 
  about 
  the 
  mechanism 
  of 
  audi- 
  

   tion, 
  and 
  still 
  less 
  about 
  the 
  resultant 
  nervous 
  stimulation 
  ? 
  

   The 
  experimental 
  facts 
  to 
  me, 
  at 
  least, 
  seem 
  irreconcilable 
  to 
  

   the 
  theory 
  of 
  locating 
  sounds 
  in 
  all 
  cases 
  by 
  intensity 
  varia- 
  

   tions, 
  and 
  none 
  of 
  the 
  objections 
  made 
  in 
  this 
  paper 
  are 
  

   pertinent 
  to 
  the 
  appreciation 
  of 
  phase-differences. 
  It 
  is 
  of 
  

   course 
  possible 
  that 
  neither 
  of 
  these 
  is 
  the 
  direct 
  cause, 
  which 
  

   may 
  be 
  something 
  in 
  the 
  sound-wave 
  affecting 
  us 
  by 
  some 
  

   unknown 
  psychological 
  influence. 
  

  

  University 
  of 
  Cincinnati, 
  

   April 
  1909. 
  

  

  