﻿ARTICLE 
  X. 
  

  

  Contributions 
  to 
  Electricity 
  and 
  Magnetism. 
  By 
  Joseph 
  Henry, 
  

   Professor 
  of 
  Natural 
  Philosophy 
  in 
  the 
  College 
  of 
  New 
  Jersey, 
  Prince- 
  

   ton, 
  late 
  of 
  the 
  Albany 
  Academy. 
  

  

  No. 
  ,11. 
  — 
  On 
  the 
  Influence 
  of 
  a 
  Spiral 
  Conductor 
  in 
  increasing 
  

   the 
  Intensity 
  of 
  Electricity 
  from 
  a 
  Galvanic 
  Arrangement 
  of 
  a 
  Single 
  

   Pair, 
  fyc. 
  Read 
  before 
  the 
  American 
  Philosophical 
  Society, 
  February 
  

   6th, 
  1835. 
  

  

  In 
  the 
  American 
  Journal 
  of 
  Science 
  for 
  July 
  1832, 
  I 
  announced 
  a 
  

   fact 
  in 
  Galvanism 
  which 
  I 
  believe 
  had 
  never 
  before 
  been 
  published. 
  

   The 
  same 
  fact, 
  however, 
  appears 
  to 
  have 
  been 
  since 
  observed 
  by 
  Mr 
  

   Faraday, 
  and 
  has 
  lately 
  been 
  noticed 
  by 
  him 
  in 
  the 
  November 
  number 
  

   of 
  the 
  London 
  and 
  Edinburgh 
  Journal 
  of 
  Science 
  for 
  1834. 
  

  

  The 
  phenomenon 
  as 
  described 
  by 
  me 
  is 
  as 
  follows. 
  " 
  When 
  a 
  small 
  

   battery 
  is 
  moderately 
  excited 
  by 
  diluted 
  acid, 
  and 
  its 
  poles, 
  terminated 
  by 
  

   cups 
  of 
  mercury, 
  are 
  connected 
  by 
  a 
  copper 
  wire 
  not 
  more 
  than 
  a 
  foot 
  

   in 
  length, 
  no 
  spark 
  is 
  perceived 
  when 
  the 
  connection 
  is 
  either 
  formed 
  

   or 
  broken 
  ; 
  but 
  if 
  a 
  wire 
  thirty 
  or 
  forty 
  feet 
  long 
  be 
  used 
  instead 
  of 
  

   the 
  short 
  wire, 
  though 
  no 
  spark 
  will 
  be 
  perceptible 
  when 
  the 
  connec- 
  

   tion 
  is 
  made, 
  yet 
  when 
  it 
  is 
  broken 
  by 
  drawing 
  one 
  end 
  of 
  the 
  wire 
  

   from 
  its 
  cup 
  of 
  mercury, 
  a 
  vivid 
  spark 
  is 
  produced. 
  If 
  the 
  action 
  of 
  

   the 
  battery 
  be 
  very 
  intense, 
  a 
  spark 
  will 
  be 
  given 
  by 
  a 
  short 
  wire 
  ; 
  in 
  

  

  