﻿Gooch 
  and 
  Kobayashi 
  — 
  Electrolytic 
  Analysis. 
  393 
  

  

  some 
  minutes 
  after 
  the 
  solution 
  had 
  been 
  completely 
  decolor- 
  

   ized 
  and 
  thereafter 
  was 
  brought 
  to 
  an 
  end 
  only 
  when 
  the 
  ferro- 
  

   cyanide 
  test 
  failed 
  to 
  give 
  any 
  indication 
  of 
  copper 
  in 
  a 
  portion 
  

   of 
  the 
  solution 
  removed 
  for 
  testing. 
  

  

  In 
  the 
  first 
  three 
  experiments 
  the 
  deposit 
  of 
  copper 
  was 
  

   washed, 
  as 
  is 
  usual, 
  with 
  a 
  water-jet 
  and 
  the 
  results 
  indicate 
  

   that 
  there 
  must 
  have 
  been 
  included 
  in 
  the 
  somewhat 
  porous 
  

   copper 
  deposited 
  at 
  a 
  high 
  current 
  density 
  (ND 
  100 
  = 
  30 
  to 
  45 
  

   amp.) 
  traces 
  of 
  sulphuric 
  acid 
  which 
  the 
  superficial 
  washing 
  

   failed 
  to 
  remove. 
  In 
  the 
  remaining 
  experiments, 
  therefore, 
  

   the 
  cathode 
  deposit 
  was 
  several 
  times 
  dipped 
  and 
  allowed 
  to 
  

   stand 
  for 
  a 
  few 
  minutes 
  in 
  distilled 
  water 
  to 
  permit 
  the 
  escape 
  

   of 
  included 
  acid 
  by 
  the 
  process 
  of 
  diffusion. 
  

  

  

  

  Table 
  I. 
  

  

  

  

  

  

  Electrolysis 
  of 
  Copper 
  Sulphate. 
  

  

  

  

  

  Copper 
  

   taken 
  as 
  

   sulphate 
  

  

  (Cathode 
  revolutions, 
  600 
  per 
  minute.) 
  

  

  Copper 
  Vol- 
  

   found 
  Error 
  Initial 
  Current 
  ume 
  

  

  H 
  2 
  S0 
  4 
  

   added 
  Time 
  

  

  grm. 
  

  

  grm. 
  

  

  grm. 
  

  

  amp. 
  volt 
  

  

  cm 
  3 
  

  

  drops 
  

  

  min. 
  

  

  

  

  Superficial 
  washing 
  only. 
  

  

  

  

  

  0-1273 
  

  

  0-1279 
  

  

  + 
  0-0006 
  

  

  0-6 
  7*8 
  

  

  30 
  

  

  5 
  

  

  40 
  

  

  0-1273 
  

  

  0*1282 
  

  

  + 
  0-0009 
  

  

  0-4 
  8 
  

  

  50 
  

  

  5 
  

  

  40 
  

  

  0-1273 
  

  

  0-1293 
  

  

  + 
  0-0020 
  

  

  0-6 
  7-8 
  

  

  100 
  

  

  10 
  

  

  50 
  

  

  Superficial 
  washing 
  supplen 
  

  

  lented 
  by 
  diffusion 
  in 
  ' 
  

  

  water. 
  

  

  

  0-1273 
  

  

  0-1271 
  

  

  — 
  0-0002 
  

  

  0-2* 
  4 
  

  

  100 
  

  

  30 
  

  

  55 
  

  

  0-1273 
  

  

  0-1274 
  

  

  + 
  0-0001 
  

  

  0-2* 
  4 
  

  

  100 
  

  

  30 
  

  

  60 
  

  

  0-1273 
  

  

  0-1271 
  

  

  — 
  0-0002 
  

  

  0-2* 
  3-8 
  

  

  100 
  

  

  30 
  

  

  60 
  

  

  0-1273 
  

  

  0*1275 
  

  

  + 
  0-0002 
  

  

  0'2* 
  3-8 
  

  

  100 
  

  

  30 
  

  

  60 
  

  

  0-1275 
  

  

  0-1276 
  

  

  + 
  0-0001 
  

  

  0-2* 
  3-9 
  

  

  100 
  

  

  39 
  

  

  60 
  

  

  *ND 
  ]0 
  o 
  = 
  15 
  amp. 
  (approx.) 
  

  

  The 
  results 
  of 
  the 
  latter 
  group 
  of 
  experiments 
  show 
  that 
  

   with 
  the 
  use 
  of 
  the 
  small 
  electrodes 
  the 
  copper 
  in 
  half 
  a 
  gram 
  

   of 
  crystallized 
  copper 
  sulphate 
  maybe 
  completely 
  precipitated 
  

   within 
  an 
  hour 
  from 
  100 
  cm 
  3 
  solution 
  acidulated 
  with 
  sulphuric 
  

   acid, 
  and 
  determined 
  with 
  a 
  high 
  degree 
  of 
  accuracy, 
  by 
  means 
  

   of 
  a 
  current 
  of 
  about 
  0'2 
  amp. 
  In 
  the 
  experiments 
  described 
  

   the 
  adjustment 
  of 
  conditions 
  was 
  such 
  that 
  this 
  current 
  was 
  

   delivered 
  under 
  a 
  potential 
  of 
  about 
  4 
  volts 
  between 
  the 
  elec- 
  

   trodes. 
  Experience 
  shows 
  that 
  the 
  amperage 
  rises 
  as 
  the 
  

   action 
  proceeds, 
  presumably 
  in 
  consequence 
  of 
  the 
  heating 
  of 
  

   the 
  liquid. 
  

  

  The 
  Determination 
  of 
  Nickel. 
  

  

  The 
  material 
  used 
  in 
  the 
  determinations 
  of 
  nickel 
  was 
  nickel 
  

   sulphate, 
  NiS0 
  4 
  .6H 
  2 
  0, 
  taken 
  in 
  a 
  solution 
  containing 
  approxi- 
  

   mately 
  0'1 
  grm. 
  of 
  nickel 
  in 
  every 
  portion 
  of 
  50 
  cm 
  3 
  . 
  The 
  

  

  