﻿254 
  

  

  Mr. 
  L. 
  Vegard 
  : 
  Researches 
  upoi 
  

  

  It 
  seems 
  as 
  if 
  I 
  have 
  succeeded 
  in 
  finding 
  a 
  type 
  of 
  cell 
  

   ivith 
  constant 
  qualities 
  and 
  very 
  convenient 
  for 
  the 
  production 
  

   of 
  semipermeahle 
  membranes. 
  The 
  cell 
  substance 
  has 
  a 
  suitable 
  

   porousness, 
  is 
  very 
  homogeneous, 
  and 
  can 
  at 
  the 
  same 
  time 
  

   stand 
  great 
  pressures. 
  

  

  In 
  making 
  the 
  membrane 
  the 
  following 
  method 
  of 
  pro- 
  

   ceeding 
  has 
  been 
  used. 
  

  

  The 
  forming 
  of 
  the 
  first 
  begin 
  nine" 
  of 
  the 
  membrane 
  for 
  

   three 
  of 
  the 
  cells 
  was 
  done 
  in 
  the 
  way 
  described 
  by 
  Berkeley 
  

   and 
  Hartley*. 
  

  

  One 
  of 
  my 
  cells 
  (A), 
  however, 
  has 
  been 
  treated 
  in 
  a 
  some- 
  

   what 
  different 
  way. 
  In 
  this 
  case 
  I 
  took 
  the 
  dry 
  cell 
  and 
  let 
  

   it 
  soak 
  the 
  two 
  solutions 
  simultaneously, 
  the 
  potassium 
  ferro- 
  

   cyanide 
  from 
  the 
  outside 
  and 
  the 
  copper 
  sulphate 
  from 
  the 
  

   inside, 
  whereupon 
  the 
  cell 
  was 
  placed 
  in 
  distilled 
  water 
  and 
  

   the 
  whole 
  placed 
  in 
  the 
  vacuum 
  for 
  about 
  twenty-four 
  hours. 
  

   The 
  result 
  was 
  very 
  satisfactory, 
  the 
  resistance 
  rose 
  more 
  

   suddenly 
  than 
  in 
  any 
  of 
  the 
  other 
  cells. 
  

  

  The 
  solution 
  of 
  copper 
  sulphate 
  used 
  contained 
  50 
  gr. 
  in 
  

   one 
  litre, 
  and 
  the 
  solution 
  of 
  potassium 
  ferrocyanide 
  42 
  gr. 
  

   in 
  the 
  litre. 
  The 
  positive 
  electrode 
  consisted 
  of 
  a 
  copper 
  

   rod, 
  and 
  the 
  vessel 
  containing 
  the 
  solution 
  served 
  as 
  the 
  

   negative 
  electrode. 
  In 
  order 
  to 
  prevent 
  the 
  potassium 
  

   hydrate 
  produced 
  by 
  the 
  electrolysis 
  from 
  acting 
  upon 
  the 
  

   membrane, 
  the 
  cell 
  was 
  separated 
  from 
  the 
  vessel 
  by 
  a 
  porous 
  

   cup 
  also 
  filled 
  with 
  potassium 
  ferrocyanide 
  solution. 
  In 
  the 
  

   electrolysis 
  the 
  positive 
  electrode 
  was 
  fixed 
  to 
  the 
  cell 
  by 
  a 
  cork 
  

   with 
  perforations, 
  and 
  the 
  cell 
  hung 
  up 
  by 
  the 
  current 
  wire. 
  

  

  At 
  the 
  beginning 
  of 
  the 
  electrolysis 
  the 
  resistance 
  suddenly 
  

   rose 
  within 
  two 
  minutes 
  to 
  about 
  3-4000 
  ohms, 
  and 
  then 
  

   increased 
  more 
  slowly 
  until 
  after 
  l-J-2 
  hours 
  it 
  reached 
  

   a 
  maximum 
  value. 
  As 
  an 
  instance 
  I 
  shall 
  give 
  the 
  observa- 
  

   tions 
  for 
  the 
  first 
  electrolysis 
  of 
  the 
  cell 
  A 
  : 
  

  

  Electrolysis 
  

  

  i 
  begun 
  Nov. 
  10, 
  1907 
  

  

  , 
  l 
  h 
  8 
  m 
  P.M. 
  

  

  Time. 
  

  

  Temp. 
  

  

  Potential. 
  

  

  Resistance. 
  

  

  l 
  h 
  9 
  m 
  

  

  9°C. 
  

  

  65 
  volts 
  

  

  3,000 
  ohms 
  

  

  11 
  

  

  7 
  

  

  96 
  „ 
  

  

  4,500 
  „ 
  

  

  33 
  

  

  6 
  

  

  107 
  „ 
  

  

  11,400 
  „ 
  

  

  48 
  

  

  5 
  

  

  110 
  „ 
  

  

  13,500 
  „ 
  

  

  2 
  25 
  

  

  4 
  

  

  111 
  „ 
  

  

  18,800 
  „ 
  

  

  3 
  30 
  

  

  3-5 
  

  

  111-5 
  „ 
  

  

  20,200 
  „ 
  

  

  If 
  the 
  electrolysis 
  is 
  continued 
  after 
  maximum 
  resistance 
  

   * 
  Earl 
  of 
  Berkeley 
  and 
  E. 
  G. 
  J. 
  Hartley, 
  he. 
  tit. 
  p. 
  486. 
  

  

  