﻿of 
  the 
  Direction 
  of 
  Sounds. 
  317 
  

  

  Fig?. 
  5 
  and 
  6 
  show 
  that 
  the 
  direction 
  o£ 
  the 
  separate 
  

   notes 
  followed 
  the 
  curve 
  as 
  i£ 
  each 
  were 
  alone 
  present, 
  and 
  

   that 
  the 
  location 
  of 
  the 
  chord 
  was 
  rather 
  more 
  influenced 
  by 
  

   the 
  lower 
  tone. 
  

  

  3. 
  Forks 
  c 
  (?i 
  = 
  256) 
  and 
  g' 
  (;i 
  = 
  384).— 
  In 
  general, 
  the 
  

   lower 
  tone 
  was 
  completely 
  blotted 
  out, 
  the 
  chord 
  was 
  heard 
  

   either 
  to 
  the 
  right 
  or 
  left, 
  and 
  the 
  higher 
  tone 
  was 
  usually 
  

   quite 
  distinct 
  and 
  its 
  direction 
  clearly 
  indicated. 
  For 
  the 
  

   most 
  part 
  the 
  direction 
  of 
  the 
  chord 
  was 
  most 
  strongly 
  

   influenced 
  by 
  the 
  theoretical 
  direction 
  of 
  the 
  higher 
  com- 
  

   ponent. 
  But 
  at 
  certain 
  positions 
  of 
  the 
  slider, 
  the 
  sound 
  

   y 
  became 
  quite 
  feeble 
  and 
  even 
  inaudible, 
  leaving 
  only 
  

   the 
  chord. 
  The 
  positions 
  where 
  this 
  occurred 
  were 
  when 
  

   the 
  theoretical 
  directions 
  of 
  the 
  two 
  component 
  waves, 
  taken 
  

   separately, 
  were 
  both 
  in 
  coincidence, 
  either 
  right, 
  left, 
  or 
  

   middle. 
  

  

  Professors 
  Myers 
  and 
  Wilson 
  have 
  offered 
  an 
  ingenious 
  

   theory 
  to 
  explain 
  the 
  effect 
  of 
  phase-difference 
  on 
  hearing. 
  

   According 
  to 
  this 
  theory 
  the 
  difference 
  of 
  phase 
  is 
  a 
  primary 
  

   cause 
  of 
  the 
  changes 
  in 
  locating 
  sounds, 
  and 
  acts 
  by 
  pro- 
  

   ducing 
  an 
  inequality 
  between 
  the 
  intensities 
  of 
  the 
  sound 
  

   inside 
  the 
  ears. 
  For 
  example, 
  a 
  sound-wave 
  enters 
  the 
  right 
  

   ear 
  with 
  a 
  certain 
  phase, 
  and 
  at 
  the 
  inner 
  ear 
  encounters 
  and 
  

   combines 
  with 
  a 
  portion 
  of 
  the 
  sound 
  which 
  entered 
  the 
  left 
  

   ear 
  and 
  passed 
  through 
  the 
  head 
  to 
  the 
  inner 
  right 
  ear. 
  

   Similarly, 
  the 
  sound-wave 
  enters 
  the 
  left 
  ear 
  but 
  at 
  a 
  dif- 
  

   ferent 
  phase, 
  and 
  there 
  meets 
  sound 
  passing 
  through 
  the 
  

   head 
  from 
  the 
  right 
  side. 
  They 
  assume 
  " 
  That 
  the 
  displace- 
  

   ments 
  in 
  the 
  internal 
  ear 
  due 
  to 
  the 
  two 
  sets 
  of 
  waves 
  are 
  in 
  

   opposite 
  directions. 
  It 
  should 
  be 
  said 
  that 
  the 
  principal 
  

   reason 
  for 
  making 
  this 
  assumption 
  is 
  that 
  it 
  enables 
  an 
  ex- 
  

   planation 
  of 
  the 
  lateral 
  effects 
  to 
  be 
  given." 
  Now 
  the 
  phases 
  

   of 
  the 
  waves 
  entering 
  the 
  ears 
  from 
  without 
  are 
  different^ 
  

   therefore 
  the 
  diminution 
  of 
  the 
  intensities 
  of 
  these 
  waves 
  by 
  

   the 
  combination 
  with 
  the 
  waves 
  conducted 
  through 
  the 
  head 
  

   is 
  unequal 
  in 
  the 
  two 
  ears. 
  And 
  we 
  are 
  supposed 
  to 
  judge 
  

   the 
  direction 
  of 
  the 
  sound 
  by 
  comparing 
  the 
  two 
  unequal 
  

   intensities 
  of 
  the 
  combined 
  waves 
  in 
  the 
  internal 
  ears. 
  In 
  

   further 
  explanation, 
  they 
  say, 
  " 
  The 
  distance 
  between 
  the 
  

   ears 
  through 
  the 
  head 
  is 
  small, 
  and 
  the 
  velocity 
  of 
  sound 
  

   through 
  the 
  bones 
  probably 
  very 
  high, 
  so 
  that 
  we 
  should 
  not 
  

   expect 
  a 
  reversal 
  of 
  the 
  effect 
  due 
  to 
  this 
  cause, 
  unless 
  the 
  

   frequency 
  were 
  very 
  great. 
  But 
  with 
  high 
  frequencies 
  the 
  

   lateral 
  effects 
  cannot 
  be 
  obtained. 
  The 
  amount 
  of 
  sound 
  

   which 
  must 
  get 
  through 
  the 
  head 
  to 
  produce 
  an 
  appreciable 
  

  

  