﻿230 
  INFLUENCE 
  OF 
  A 
  SPIRAL 
  CONDUCTOR 
  

  

  wires. 
  If 
  a 
  current 
  of 
  free 
  electricity 
  be 
  passed 
  through 
  A, 
  the 
  natu- 
  

   ral 
  equilibrium 
  of 
  B 
  will 
  be 
  disturbed 
  for 
  an 
  instant, 
  in 
  a 
  similar 
  manner 
  

   to 
  the 
  disturbance 
  of 
  the 
  equilibrium 
  in 
  an 
  insulated 
  conductor, 
  by 
  the 
  

   sudden 
  addition 
  of 
  fluid 
  to 
  a 
  contiguous 
  conductor. 
  On 
  account 
  of 
  the 
  

   repulsive 
  action 
  of 
  the 
  fluid, 
  the 
  current 
  in 
  B 
  will 
  have 
  an 
  opposite 
  

   direction 
  to 
  that 
  in 
  A 
  ; 
  and 
  if 
  the 
  intensity 
  of 
  action 
  remains 
  constant, 
  

   a 
  new 
  state 
  of 
  equilibrium 
  will 
  be 
  assumed. 
  The 
  second 
  state, 
  how- 
  

   ever, 
  of 
  B 
  may 
  perhaps 
  be 
  regarded 
  as 
  one 
  of 
  tension, 
  and 
  as 
  soon 
  as 
  

   the 
  extra 
  action 
  ceases 
  in 
  it, 
  the 
  fluid 
  in 
  B 
  will 
  resume 
  its 
  natural 
  state 
  

   of 
  distribution, 
  and 
  thus 
  a 
  returning 
  current 
  for 
  an 
  instant 
  be 
  produced. 
  

  

  The 
  action 
  of 
  the 
  spiral 
  conductor 
  in 
  producing 
  sparks, 
  is 
  but 
  another 
  

   case 
  of 
  the 
  same 
  action 
  ; 
  for 
  since 
  action 
  and 
  reaction 
  are 
  equal 
  and 
  in 
  

   contrary 
  directions, 
  if 
  a 
  current 
  established 
  in 
  A 
  produces 
  a 
  current 
  in 
  

   an 
  opposite 
  direction 
  in 
  B, 
  then 
  a 
  current 
  transmitted 
  through 
  B 
  should 
  

   accelerate 
  or 
  increase 
  the 
  intensity 
  of 
  a 
  current 
  already 
  existing 
  in 
  the 
  

   same 
  direction 
  in 
  A. 
  In 
  this 
  way 
  the 
  current 
  in 
  the 
  several 
  successive 
  

   spires 
  of 
  the 
  coil 
  maybe 
  conceived 
  to 
  accelerate, 
  or 
  to 
  tend 
  to 
  accelerate 
  

   each 
  other: 
  aud 
  when 
  the 
  contact 
  is 
  broken, 
  the 
  fluid 
  of 
  the 
  first 
  spire 
  

   is 
  projected 
  from 
  it 
  with 
  intensity 
  by 
  the 
  repulsive 
  action 
  of 
  the 
  fluid 
  

   in 
  all 
  the 
  succeeding 
  spires. 
  

  

  In 
  the 
  case 
  of 
  the 
  double 
  spiral 
  conductor, 
  in 
  experiment 
  sixth, 
  the 
  

   fluid 
  is 
  passing 
  in 
  an 
  opposite 
  direction 
  ; 
  and 
  according 
  to 
  the 
  same 
  

   views, 
  a 
  retardation 
  or 
  decrease 
  of 
  intensity 
  should 
  take 
  place. 
  

  

  The 
  phenomenon 
  of 
  the 
  secondary 
  shock 
  with 
  the 
  battery, 
  appears 
  

   to 
  me 
  to 
  be 
  a 
  consequence 
  of 
  the 
  law 
  of 
  Mr 
  Faraday. 
  The 
  parts 
  of 
  

   the 
  human 
  body 
  contiguous 
  to 
  those 
  through 
  which 
  the 
  principal 
  cur- 
  

   rent 
  is 
  passing, 
  may 
  be 
  considered 
  as 
  in 
  the 
  state 
  of 
  the 
  second 
  wire 
  B 
  ; 
  

   when 
  the 
  principal 
  current 
  ceases, 
  a 
  shock 
  is 
  produced 
  by 
  the 
  returning 
  

   current 
  of 
  the 
  natural 
  electricity 
  of 
  the 
  body. 
  

  

  If 
  this 
  explanation 
  be 
  correct, 
  the 
  same 
  principle 
  will 
  readily 
  account 
  

   for 
  a 
  curious 
  phenomenon 
  discovered 
  several 
  years 
  since 
  by 
  Savary, 
  but 
  

   which 
  I 
  believe 
  still 
  remains 
  an 
  isolated 
  fact. 
  When 
  a 
  current 
  is 
  trans- 
  

   mitted 
  through 
  a 
  wire, 
  and 
  a 
  number 
  of 
  small 
  needles 
  are 
  placed 
  trans- 
  

   verse 
  to 
  it, 
  but 
  at 
  different 
  distances, 
  the 
  direction 
  of 
  the 
  magnetic 
  

   polarity 
  of 
  the 
  needles 
  varies 
  with 
  their 
  distance 
  from 
  the 
  conducting 
  

   wire. 
  The 
  action 
  is 
  also 
  periodical 
  ; 
  diminishing 
  as 
  the 
  distance 
  in- 
  

  

  