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  XLVIII. 
  An 
  Experimental 
  Investigation 
  into 
  the 
  f 
  Shin 
  3 
  -effect 
  

   in 
  Electrical 
  Oscillators. 
  By 
  C. 
  A. 
  Chant*. 
  

  

  1. 
  Introductory 
  and 
  Theoretical. 
  

  

  rilHE 
  first 
  explicit 
  reference 
  to 
  the 
  fact 
  that, 
  when 
  a 
  con- 
  

   JL 
  dnctor 
  is 
  subjected 
  to 
  a 
  periodic 
  electromotive 
  force, 
  

   the 
  current 
  is 
  not 
  uniformly 
  distributed 
  over 
  a 
  cross-section 
  

   of 
  the 
  conductor 
  is 
  to 
  be 
  found 
  in 
  Art. 
  690 
  of 
  Maxwell's 
  

   'Electricity 
  and 
  Magnetism.' 
  Upon 
  obtaining 
  the 
  equation 
  

   connecting 
  the 
  impressed 
  electromotive 
  force 
  with 
  the 
  

   effective 
  electromotive 
  force 
  and 
  the 
  inductive 
  electromotive 
  

   force, 
  he 
  introduces 
  terms 
  which 
  u 
  express 
  the 
  correction 
  of 
  

   this 
  value 
  [of 
  the 
  inductive 
  electromotive 
  force] 
  arising 
  from 
  

   the 
  fact 
  that 
  the 
  current 
  is 
  not 
  of 
  uniform 
  strength 
  at 
  differ- 
  

   ent 
  distances 
  from 
  the 
  axis 
  of 
  the 
  wire. 
  The 
  actual 
  system 
  

   of 
  currents 
  has 
  a 
  greater 
  degree 
  of 
  freedom 
  than 
  the 
  hypo- 
  

   thetical 
  system 
  in 
  which 
  the 
  current 
  is 
  constrained 
  to 
  be 
  of 
  

   uniform 
  strength 
  throughout 
  the 
  section. 
  Hence 
  the 
  electro- 
  

   motive 
  force 
  required 
  to 
  produce 
  a 
  rapid 
  change 
  in 
  the 
  

   strength 
  of 
  the 
  current 
  is 
  somewhat 
  less 
  than 
  it 
  would 
  be 
  on 
  

   this 
  hypothesis.'" 
  

  

  It 
  is 
  quite 
  certain, 
  however, 
  that 
  Maxwell 
  did 
  not 
  foresee 
  

   the 
  great 
  interest 
  and 
  importance 
  which 
  the 
  subject 
  was 
  

   destined 
  soon 
  to 
  develop. 
  

  

  In 
  a 
  series 
  of 
  papers 
  written 
  between 
  1884 
  and 
  1887, 
  

   Heaviside 
  f 
  dealt 
  with 
  the 
  entire 
  question 
  of 
  the 
  propagation 
  

   of 
  electric 
  currents 
  into 
  conductors 
  and 
  of 
  magnetization 
  

   into 
  cores 
  when 
  produced 
  by 
  a 
  periodic 
  electromotive 
  force. 
  

   He 
  was 
  one 
  pf 
  the 
  first 
  to 
  insist 
  that 
  the 
  action 
  should 
  be 
  

   considered 
  as 
  entering 
  the 
  conductor 
  from 
  the 
  surrounding 
  

   dielectric. 
  He 
  compares 
  the 
  transmission 
  of 
  the 
  effect 
  into 
  

   the 
  metal 
  to 
  the 
  transmission 
  of 
  motion 
  into 
  the 
  inner 
  por- 
  

   tions 
  of 
  liquid 
  in 
  a 
  cylindrical 
  vessel 
  when 
  the 
  vessel 
  is 
  given 
  

   ^ 
  rotatory 
  vibration 
  about 
  its 
  axis. 
  

  

  Especial 
  attention 
  was 
  drawn 
  to 
  the 
  subject 
  by 
  Hughes 
  %> 
  

   who 
  treated 
  the 
  question 
  experimentally. 
  

  

  In 
  1886 
  Rayleigh 
  § 
  published 
  his 
  well-known 
  paper 
  in 
  

   which 
  he 
  obtained 
  expressions 
  for 
  the 
  resistance 
  and 
  self- 
  

   induction 
  of 
  a 
  straight 
  conductor 
  carrying 
  a 
  periodic 
  current. 
  

  

  * 
  Communicated 
  by 
  Prof. 
  J. 
  Trowbridge, 
  

   t 
  Electrical 
  Papers, 
  vol. 
  i. 
  pp. 
  353, 
  429 
  ; 
  vol. 
  ii. 
  p. 
  168. 
  

   X 
  Jour. 
  Soc. 
  Tel. 
  Engineers, 
  Jan. 
  28, 
  1886. 
  

  

  § 
  "On 
  the 
  Resistance 
  and 
  Self-induction 
  of 
  Straight 
  Conductors,*' 
  

   Phil. 
  Mag., 
  May 
  1886, 
  p. 
  382 
  ; 
  Scientific 
  Papers, 
  vol. 
  ii. 
  p. 
  486. 
  

   Phil. 
  Mag. 
  S. 
  6. 
  Vol. 
  3. 
  No. 
  16. 
  April 
  1902. 
  2 
  F 
  

  

  