﻿148 
  Mr. 
  John 
  S. 
  Townsend 
  on 
  Electrical 
  

  

  electrode 
  will 
  be 
  seen 
  to 
  have 
  dissolved 
  in 
  the 
  acid 
  not 
  only 
  

   round 
  the 
  positive 
  electrode, 
  but 
  also 
  round 
  the 
  negative, 
  

   before 
  the 
  change 
  of 
  sign 
  is 
  observed 
  in 
  the 
  hydrogen. 
  If 
  

   now 
  this 
  acid 
  be 
  removed 
  from 
  G 
  and 
  the 
  electrodes 
  well 
  

   washed, 
  and 
  a 
  fresh 
  quantity 
  of 
  acid 
  used, 
  it 
  will 
  be 
  found 
  

   that 
  the 
  electrometer 
  will 
  indicate 
  charges 
  on 
  the 
  hydrogen 
  

   exactly 
  similar 
  to 
  those 
  at 
  first 
  observed, 
  except 
  that 
  the 
  

   positive 
  charges 
  are 
  not 
  so 
  large. 
  

  

  After 
  washing 
  the 
  electrodes 
  a 
  second 
  time, 
  and 
  experi- 
  

   menting 
  again 
  with 
  a 
  fresh 
  quantity 
  of 
  acid, 
  the 
  same 
  effect 
  

   will 
  be 
  observed 
  without 
  any 
  further 
  diminution 
  in 
  the 
  positive 
  

   charges. 
  

  

  The 
  number 
  of 
  divisions 
  of 
  the 
  scale 
  obtained 
  in 
  an 
  experi- 
  

   ment 
  of 
  this 
  kind 
  are 
  : 
  — 
  

  

  1st 
  minute, 
  

  

  14 
  divisions 
  

  

  positive. 
  

  

  2nd 
  

  

  >> 
  

  

  11 
  

  

  » 
  

  

  >> 
  

  

  3rd 
  

  

  ?? 
  

  

  5 
  

  

  v 
  

  

  V 
  

  

  After 
  a 
  few 
  minutes 
  the 
  hydrogen 
  came 
  off 
  with 
  a 
  negative 
  

   charge, 
  corresponding 
  to 
  five 
  divisions 
  per 
  minute. 
  The 
  

   current 
  through 
  the 
  electrolyte 
  being 
  ten 
  amperes, 
  and 
  the 
  

   value 
  of 
  divisions 
  on 
  the 
  electrometer-scale 
  in 
  absolute 
  units 
  

   of 
  quantity 
  being 
  obtained 
  by 
  multipling 
  them 
  by 
  *003. 
  

  

  When 
  the 
  chlorine 
  was 
  similarly 
  examined 
  it 
  was 
  found 
  

   to 
  have 
  a 
  small 
  negative 
  charge, 
  corresponding 
  to 
  four 
  

   divisions 
  of 
  the 
  electrometer-scale 
  per 
  minute. 
  It 
  did 
  not 
  

   vary 
  in 
  sign 
  like 
  the 
  charge 
  on 
  the 
  hydrogen. 
  

  

  27. 
  It 
  is 
  probable 
  that 
  the 
  remarkable 
  change 
  of 
  sign 
  

   that 
  occurs 
  in 
  the 
  charge 
  carried 
  by 
  the 
  hydrogen 
  is 
  due 
  

   more 
  to 
  the 
  absorption 
  of 
  chlorine 
  gas 
  by 
  the 
  carbon 
  elec- 
  

   trode, 
  than 
  to 
  the 
  presence 
  of 
  chlorine 
  gas 
  in 
  the 
  electrolyte 
  ; 
  

   for 
  when 
  platinum 
  electrodes 
  were 
  used 
  the 
  hydrogen 
  was 
  

   given 
  off 
  with 
  a 
  large 
  positive 
  charge 
  and 
  did 
  not 
  change 
  

   when 
  the 
  chlorine 
  got 
  dissolved 
  in 
  the 
  electrolyte. 
  

  

  It 
  is 
  improbable 
  that 
  the 
  effect 
  is 
  due 
  merely 
  to 
  the 
  change 
  

   from 
  platinum 
  to 
  carbon, 
  as 
  there 
  was 
  no 
  corresponding 
  

   change 
  when 
  similar 
  experiments 
  were 
  performed 
  with 
  sul- 
  

   phuric 
  acid 
  ; 
  the 
  positive 
  charge 
  on 
  the 
  hydrogen 
  evolved 
  

   being 
  large 
  whether 
  platinum 
  or 
  carbon 
  terminals 
  were 
  used 
  ; 
  

   and 
  no 
  change 
  occurred 
  by 
  running 
  the 
  current 
  for 
  half-an- 
  

   hour, 
  except 
  a 
  gradual 
  increase 
  in 
  the 
  charge, 
  which 
  can 
  be 
  

   shown 
  to 
  be 
  due 
  to 
  a 
  rise 
  in 
  temperature. 
  It 
  was 
  also 
  found 
  

   that 
  the 
  charge 
  on 
  the 
  hydrogen 
  was 
  increased 
  by 
  using 
  a 
  

   new 
  carbon 
  electrode, 
  instead 
  of 
  that 
  used 
  with 
  the 
  hydro- 
  

   chloric 
  acid. 
  

  

  