﻿464 
  

  

  On 
  Electrolytic 
  Conduction 
  in 
  Solids. 
  

  

  [June 
  10, 
  

  

  than 
  at 
  higher 
  temperatures. 
  If 
  the 
  glass 
  is 
  kept 
  at 
  50° 
  0. 
  for 
  some 
  

   time, 
  and 
  I, 
  after 
  having 
  been 
  metallically 
  connected 
  with 
  P, 
  is 
  left 
  insu- 
  

   lated, 
  it 
  soon 
  becomes 
  sensibly 
  charged 
  ; 
  and 
  the 
  charge 
  increases 
  till 
  

   it 
  is 
  approximately 
  equal 
  to 
  that 
  acquired 
  when 
  zinc 
  and 
  copper 
  

   plates 
  in 
  a 
  liquid 
  electrolyte 
  are 
  metallically 
  connected 
  with 
  I 
  and 
  E 
  

   respectively. 
  With 
  the 
  hot 
  glass, 
  as 
  with 
  the 
  liquid 
  electrolyte, 
  the 
  

   charge 
  given 
  by 
  the 
  zinc 
  to 
  the 
  insulated 
  electrode 
  of 
  the 
  electrometer 
  is 
  

   negative. 
  The 
  charge 
  ultimately 
  reached 
  when 
  the 
  temperature 
  is 
  50° 
  is 
  

   not 
  exceeded 
  at 
  higher 
  temperatures 
  ; 
  but, 
  as 
  said 
  above, 
  when 
  the 
  zinc 
  

   is 
  connected 
  with 
  the 
  copper 
  and 
  then 
  insulated, 
  the 
  charge 
  increases 
  

   towards 
  its 
  ultimate 
  value 
  much 
  more 
  rapidly 
  at 
  higher 
  temperatures 
  

   than 
  at 
  lower. 
  

  

  At 
  temperatures 
  between 
  100° 
  and 
  120° 
  C. 
  there 
  is 
  a 
  sensible 
  diminu- 
  

   tion 
  of 
  the 
  ultimate 
  charge 
  after 
  the 
  zinc 
  has 
  been 
  kept 
  for 
  a 
  short 
  time 
  

   connected 
  with 
  the 
  copper 
  and 
  then 
  insulated. 
  There 
  is 
  also 
  a 
  slow 
  

   diminution 
  of 
  the 
  ultimate, 
  or, 
  as 
  we 
  may 
  now 
  call 
  it, 
  the 
  temporarily 
  

   static, 
  charge 
  when 
  the 
  zinc 
  plate 
  is 
  left 
  insulated 
  for 
  several 
  hours 
  in 
  

   connexion 
  with 
  I. 
  

  

  If 
  a 
  small 
  quantity 
  of 
  either 
  negative 
  or 
  positive 
  electricity 
  be 
  given 
  to 
  

   I 
  (always 
  in 
  metallic 
  connexion 
  with 
  the 
  zinc), 
  the 
  temporarily 
  static 
  

   state 
  is 
  reached 
  at 
  about 
  the 
  same 
  rate 
  as 
  the 
  zero 
  would 
  be 
  reached 
  by 
  

   conduction 
  through 
  the 
  hot 
  glass 
  (according 
  to 
  Mr. 
  Perry's 
  experiments, 
  

   communicated 
  to 
  the 
  present 
  Meetiug) 
  were 
  the 
  plates 
  both 
  of 
  copper 
  or 
  

   both 
  of 
  zinc. 
  

  

  After 
  the 
  experiment 
  the 
  surfaces 
  of 
  the 
  copper 
  and 
  zinc 
  plates 
  in 
  con- 
  

   tact 
  with 
  the 
  glass 
  were 
  found 
  to 
  be 
  thickly 
  oxidized. 
  The 
  glass 
  plate 
  

   was 
  quite 
  cloudy 
  after 
  the 
  experiment, 
  and 
  a 
  repetition 
  of 
  the 
  experiment 
  

   increased 
  its 
  cloudiness. 
  This 
  plate 
  is 
  the 
  flattened 
  bottom 
  of 
  a 
  flint- 
  

   glass 
  electrometer-jar. 
  

  

  Three 
  smoother 
  glass 
  plates, 
  tried 
  since, 
  show 
  as 
  yet 
  no 
  signs 
  of 
  decom- 
  

   position. 
  At 
  first 
  they 
  only 
  became 
  " 
  exhausted 
  " 
  (in 
  their 
  power 
  to 
  pro- 
  

   duce 
  the 
  normal 
  charge 
  in 
  zinc 
  and 
  copper) 
  after 
  the 
  plates 
  had 
  been 
  

   connected 
  for 
  nearly 
  a 
  day, 
  the 
  glass 
  beiug 
  at 
  from 
  100° 
  to 
  120° 
  C. 
  ; 
  

   but 
  after 
  a 
  time, 
  although 
  they 
  still 
  gave 
  the 
  normal 
  charge 
  at 
  the 
  

   beginning 
  of 
  the 
  morning's 
  experiments, 
  the 
  charge 
  fell 
  to 
  zero 
  quite 
  

   rapidly 
  (that 
  is, 
  in 
  about 
  an 
  hour), 
  even 
  when 
  the 
  zinc 
  was 
  kept 
  in- 
  

   sulated. 
  

  

  Keeping 
  for 
  a 
  length 
  of 
  time 
  the 
  zinc 
  charged 
  negatively 
  (so 
  as 
  to 
  give 
  

   to 
  I 
  a 
  greater 
  negative 
  charge 
  than 
  that 
  which 
  it 
  would 
  have 
  in 
  the 
  

   " 
  temporarily 
  static 
  " 
  condition 
  of 
  the 
  copper, 
  hot 
  glass, 
  and 
  zinc) 
  seemed 
  

   to 
  have 
  no 
  effect 
  in 
  restoring 
  the 
  normal 
  electrolytic 
  condition; 
  but 
  I 
  

   propose 
  to 
  pursue 
  this 
  trial 
  further, 
  especially 
  with 
  longer 
  time 
  for 
  the 
  

   restorative 
  electrification. 
  

  

  I 
  propose 
  also 
  to 
  return 
  to 
  similar 
  experiments 
  which 
  I 
  made 
  many 
  

   years 
  ago 
  on 
  the 
  electric 
  relations 
  of 
  copper, 
  ice, 
  and 
  zinc. 
  

  

  