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  INFLUENCE 
  OF 
  A 
  SPIRAL 
  CONDUCTOR 
  

  

  the 
  double 
  spiral 
  gave 
  no 
  spark 
  whatever, 
  while 
  the 
  other 
  ribbon 
  coiled 
  

   into 
  a 
  single 
  spiral 
  produced 
  as 
  before 
  a 
  loud 
  snap. 
  Lest 
  the 
  effect 
  

   might 
  be 
  due 
  to 
  some 
  accidental 
  touching 
  of 
  the 
  different 
  spires, 
  the 
  

   double 
  spiral 
  was 
  covered 
  with 
  an 
  additional 
  coating 
  of 
  silk, 
  and 
  also 
  

   the 
  other 
  ribbon 
  was 
  coiled 
  in 
  the 
  same 
  manner 
  ; 
  the 
  effect 
  with 
  both 
  

   was 
  the 
  same. 
  

  

  7. 
  In 
  order 
  to 
  increase 
  if 
  possible 
  the 
  intensity 
  of 
  the 
  spark 
  while 
  

   the 
  battery 
  remained 
  the 
  same, 
  larger 
  spirals 
  were 
  applied 
  in 
  succession. 
  

   The 
  effect 
  was 
  increased 
  until 
  one 
  of 
  ninety-six 
  feet 
  long, 
  an 
  inch 
  and 
  

   a 
  half 
  wide 
  and 
  weighing 
  fifteen 
  pounds, 
  was 
  used. 
  The 
  snap 
  from 
  

   this 
  was 
  so 
  loud 
  that 
  it 
  could 
  be 
  distinctly 
  heard 
  in 
  an 
  adjoining 
  room 
  

   with 
  the 
  intervening 
  door 
  closed. 
  Want 
  of 
  materials 
  has 
  prevented 
  

   me 
  from 
  trying 
  a 
  larger 
  spiral 
  conductor 
  than 
  this, 
  but 
  it 
  is 
  probable 
  

   that 
  there 
  is 
  a 
  length 
  which, 
  with 
  a 
  given 
  quantity 
  and 
  intensity 
  of 
  

   galvanism 
  would 
  produce 
  a 
  maximum 
  effect. 
  When 
  the 
  size 
  of 
  the 
  

   battery 
  is 
  increased, 
  a 
  much 
  greater 
  effect 
  is 
  produced 
  with 
  the 
  same 
  

   spiral. 
  Thus 
  when 
  the 
  galvanic 
  apparatus 
  described 
  in 
  the 
  first 
  article 
  

   is 
  arranged 
  as 
  a 
  calorimotor 
  of 
  eight 
  pairs, 
  the 
  snap 
  produced 
  on 
  break- 
  

   ing 
  contact 
  with 
  the 
  spiral 
  last 
  described, 
  resembled 
  the 
  discharge 
  of 
  a 
  

   small 
  Leyden 
  jar 
  highly 
  charged. 
  

  

  8. 
  A 
  handle 
  of 
  thick 
  copper 
  was 
  soldered 
  on 
  each 
  end 
  of 
  the 
  large 
  

   spiral 
  at 
  right 
  angles 
  to 
  the 
  ribbon, 
  similar 
  to 
  those 
  attached 
  to 
  the 
  

   wires 
  in 
  Pixii's 
  magneto-electric 
  machine 
  for 
  giving 
  shocks. 
  When 
  

   one 
  of 
  these 
  was 
  grasped 
  by 
  each 
  hand 
  and 
  the 
  contact 
  broken, 
  a 
  shock 
  

   was 
  received 
  which 
  was 
  felt 
  at 
  the 
  elbows, 
  and 
  this 
  was 
  repeated 
  as 
  

   often 
  as 
  the 
  contact 
  was 
  broken. 
  This 
  shock 
  is 
  rather 
  a 
  singular 
  phe- 
  

   nomenon, 
  since 
  it 
  appears 
  to 
  be 
  produced 
  by 
  a 
  lateral 
  discharge, 
  and 
  it 
  

   is 
  therefore 
  important 
  to 
  determine 
  its 
  direction 
  in 
  reference 
  to 
  the 
  

   primary 
  current. 
  

  

  A 
  shock 
  is 
  also 
  received 
  when 
  the 
  copper 
  of 
  the 
  battery 
  is 
  grasped 
  

   by 
  one 
  hand, 
  and 
  the 
  handle 
  attached 
  to 
  the 
  copper 
  pole 
  of 
  the 
  ribbon 
  

   with 
  the 
  other. 
  This 
  may 
  be 
  called 
  the 
  direct 
  shock, 
  since 
  it 
  is 
  pro- 
  

   duced 
  by 
  a 
  part 
  of 
  the 
  direct 
  current. 
  It 
  is, 
  however, 
  far 
  less 
  intense 
  

   than 
  that 
  produced 
  by 
  the 
  lateral 
  discharge. 
  

  

  10. 
  When 
  the 
  poles 
  were 
  joined 
  by 
  two 
  coils 
  connected 
  by 
  a 
  cup 
  of 
  

   mercury 
  between 
  them, 
  a 
  spark 
  was 
  produced 
  by 
  breaking 
  the 
  circuit 
  

  

  