﻿132 
  Prof. 
  G. 
  W. 
  0. 
  Howe 
  on 
  the 
  

  

  Ziooo=3 
  , 
  15R 
  . 
  In 
  the 
  case 
  of 
  a 
  60-ohm 
  receiver, 
  it 
  was 
  

   found 
  that 
  Z 
  637 
  = 
  4 
  , 
  27R, 
  and 
  Zin5 
  = 
  6 
  , 
  35E 
  . 
  As 
  a 
  rule 
  at 
  

   such 
  frequencies 
  the 
  reactance 
  is 
  of 
  the 
  same 
  order 
  as 
  the 
  

   effective 
  resistance, 
  so 
  that 
  the 
  current 
  lags 
  about 
  45° 
  behind 
  

   the 
  terminal 
  P.D. 
  ; 
  this 
  is, 
  of 
  course, 
  merely 
  a 
  rough 
  

   approximation. 
  

  

  There 
  may 
  be 
  some 
  doubt 
  as 
  to 
  the 
  correctness 
  of 
  treating 
  

   the 
  pulsating 
  telephone 
  current 
  as 
  a 
  simple 
  alternating 
  

   current 
  ; 
  but 
  in 
  the 
  opinion 
  of 
  the 
  writer, 
  the 
  pulsating 
  

   current 
  of 
  audible 
  frequency 
  produced 
  by 
  the 
  detector 
  as 
  the 
  

   result 
  of 
  the 
  successive 
  wave-trains 
  may 
  be 
  regarded 
  as 
  a 
  

   steady 
  current 
  with 
  a 
  fundamental 
  alternating 
  current 
  and 
  a 
  

   number 
  of 
  harmonics 
  superposed 
  upon 
  it, 
  the 
  fundamental 
  

   giving 
  the 
  pitch, 
  and 
  the 
  harmonics 
  the 
  character 
  of 
  the 
  sound 
  

   heard 
  in 
  the 
  receiver. 
  If 
  the 
  character 
  of 
  the 
  note 
  remain 
  

   constant, 
  it 
  would 
  appear 
  sufficient 
  to 
  consider 
  the 
  amplitude 
  

   of 
  the 
  fundamental, 
  and 
  to 
  assume 
  that 
  this 
  sinusoidal 
  current 
  

   divides 
  between 
  the 
  receiver 
  and 
  the 
  shunt 
  in 
  accordance 
  

   with 
  the 
  ordinary 
  laws 
  of 
  alternating-current 
  circuits. 
  

  

  The 
  writer 
  is 
  well 
  aware 
  that 
  references 
  can 
  be 
  given 
  to 
  

   papers 
  in 
  which 
  the 
  ordinary 
  continuous 
  current-resistance 
  

   of 
  the 
  receiver 
  was 
  apparently 
  used 
  in 
  calculating 
  the 
  audi- 
  

   bility 
  factor, 
  but 
  in 
  a 
  recent 
  paper 
  Austin, 
  who 
  has 
  done 
  

   much 
  experimental 
  work 
  on 
  this 
  subject, 
  is 
  careful 
  to 
  point 
  

   out 
  that 
  the 
  effective 
  resistance 
  of 
  the 
  receiver 
  must 
  be 
  

   determined 
  for 
  the 
  given 
  frequency 
  and 
  telephone 
  pulse 
  

   form 
  *. 
  

  

  Since 
  Mr. 
  van 
  der 
  Pol 
  refers 
  to 
  papers 
  by 
  Hogan 
  and 
  

   Love, 
  both 
  of 
  whom 
  refer 
  to 
  the 
  impedance 
  and 
  not 
  the 
  

   resistance 
  oE 
  the 
  telephone-receiver, 
  it 
  is 
  possible 
  that 
  he 
  has 
  

   also 
  used 
  the 
  impedance, 
  notwithstanding 
  the 
  statement 
  in 
  his 
  

   paper. 
  If 
  so, 
  the 
  paper 
  would 
  be 
  of 
  greater 
  value 
  and 
  

   interest 
  were 
  this 
  definitely 
  stated. 
  

  

  If 
  Mr. 
  van 
  der 
  Pol 
  did 
  not 
  take 
  the 
  precaution 
  to 
  keep 
  

   the 
  resistance 
  of 
  the 
  detector 
  circuit 
  approximately 
  con- 
  

   stant, 
  as 
  mentioned 
  above, 
  the 
  correctness 
  of 
  his 
  experimental 
  

   results 
  is 
  open 
  to 
  some 
  doubt. 
  

  

  In 
  order 
  to 
  see 
  in 
  what 
  direction 
  his 
  results 
  would 
  be 
  

   modified 
  by 
  employing 
  the 
  impedance 
  of 
  the 
  receiver 
  

   instead 
  of 
  the 
  resistance, 
  it 
  has 
  been 
  assumed 
  in 
  the 
  follow- 
  

   ing 
  table 
  that 
  the 
  impedance 
  Z 
  is 
  equal 
  to 
  four 
  times 
  the 
  

   resistance 
  R 
  , 
  and 
  that 
  the 
  telephone 
  current 
  lags 
  45 
  degrees 
  

   behind 
  the 
  P.D. 
  

  

  The 
  values 
  obtained 
  from 
  the 
  simple 
  vector 
  diagram 
  are 
  

   as 
  follows 
  : 
  — 
  

  

  * 
  Proc. 
  Inst. 
  Radio-Engineers, 
  1917, 
  v. 
  p. 
  239. 
  

  

  