﻿264 
  Gooch 
  and 
  Morley 
  — 
  Determination 
  of 
  Gold. 
  

  

  sitj 
  for 
  diluting 
  tlie 
  mixture 
  of 
  gold 
  chloride 
  and 
  the 
  iodide 
  

  

  before 
  titrating 
  with 
  the 
  thiosiilphatc. 
  It 
  was 
  found, 
  however, 
  

  

  N 
  

  

  that 
  when 
  the 
  solution 
  of 
  iodine 
  is 
  employed 
  a 
  correction 
  

  

  1000 
  ^ 
  *^ 
  

  

  of 
  O'l^"' 
  for 
  volumes 
  not 
  exceeding 
  30^""' 
  becomes 
  necessary 
  — 
  

  

  the 
  amount 
  required 
  to 
  bring 
  out 
  the 
  rose 
  color 
  in 
  blank 
  tests 
  

  

  containing 
  no 
  ffold. 
  After 
  the 
  introduction 
  of 
  0*1'^™^ 
  of 
  

  

  ^ 
  ^ 
  1000 
  

  

  iodine 
  into 
  a 
  mixture 
  of 
  potassium 
  iodide 
  and 
  starch 
  indicator 
  

   of 
  volume 
  not 
  exceeding 
  30°°^', 
  a 
  single 
  drop 
  of 
  the 
  gold 
  solu- 
  

   tion—equivalent 
  to 
  0*000002 
  grm. 
  of 
  gold 
  — 
  gave 
  a 
  distinct 
  rose 
  

   color: 
  before 
  such 
  adjustment 
  of 
  the 
  solution 
  five 
  drops 
  — 
  

   equivalent 
  to 
  O'OOOOIO 
  grm. 
  of 
  gold 
  — 
  were 
  needed 
  to 
  develop 
  

   the 
  same 
  color. 
  

  

  

  

  

  Table 
  II. 
  

  

  

  

  Gold 
  chloride 
  

  

  

  

  = 
  0-0871 
  to 
  

  

  1 
  liter. 
  

  

  

  Sodium 
  thiosulphate, 
  nearly 
  -— 
  - 
  

   N 
  100 
  

  

  = 
  1-7012 
  ' 
  

  

  u 
  

  

  

  Iodine, 
  nearly 
  ^^^, 
  

  

  

  = 
  1-3697 
  ' 
  

  

  (( 
  

  

  

  Solution 
  of 
  gold 
  chlori 
  

  

  de 
  not 
  dilu 
  

  

  ted 
  before 
  mixing 
  with 
  potassium 
  iodide. 
  

  

  

  AuCla 
  

  

  KI 
  

  

  NaaSaOg 
  

  

  A 
  

  

  Gold 
  

  

  Gold 
  

  

  

  

  taken. 
  

  

  taken. 
  

  

  used. 
  

  

  taken. 
  

  

  found. 
  

  

  Error. 
  

  

  

  cm^. 
  

  

  grm. 
  

  

  cm^. 
  

  

  grm. 
  

  

  grm. 
  

  

  grm. 
  

  

  ( 
  1) 
  

  

  10 
  

  

  0-01 
  

  

  0-83 
  

  

  0-00087 
  

  

  0-00088 
  

  

  + 
  0-00001 
  

  

  ( 
  2) 
  

  

  10 
  

  

  001 
  

  

  0-83 
  

  

  a 
  

  

  0-00088 
  

  

  + 
  0-OOOUL 
  

  

  ( 
  3) 
  

  

  10 
  

  

  0-01 
  

  

  0-80 
  

  

  u 
  

  

  0-00085 
  

  

  — 
  0-00002 
  

  

  ( 
  4) 
  

  

  10 
  

  

  0-02 
  

  

  0-84 
  

  

  u 
  

  

  0-00089 
  

  

  + 
  0-00002 
  

  

  ( 
  5) 
  

  

  10 
  

  

  0-02 
  

  

  0-88 
  

  

  (< 
  

  

  0-00093 
  

  

  + 
  0-00006 
  

  

  ( 
  6) 
  

  

  10 
  

  

  0-02 
  

  

  0-82 
  

  

  ii. 
  

  

  0-00087 
  

  

  0-00000 
  

  

  ( 
  '^) 
  

  

  10 
  

  

  0-02 
  

  

  0-8& 
  

  

  a 
  

  

  0-00093 
  

  

  + 
  0-00006 
  

  

  ( 
  s) 
  

  

  10 
  

  

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  0-83 
  

  

  a 
  

  

  0-00088 
  

  

  + 
  0-00001 
  

  

  ( 
  9) 
  

  

  10 
  

  

  0-10 
  

  

  0-80 
  

  

  (C 
  

  

  0-00085 
  

  

  — 
  0-00002 
  

  

  (10) 
  

  

  10 
  

  

  0-10 
  

  

  0-82 
  

  

  (< 
  

  

  0-00087 
  

  

  0-00000 
  

  

  (11) 
  

  

  10 
  

  

  0-01 
  

  

  0-83 
  

  

  (( 
  

  

  0-00088 
  

  

  + 
  0-00001 
  

  

  (12) 
  

  

  9 
  

  

  0-01 
  

  

  0-73 
  

  

  0-00078 
  

  

  0-00077' 
  

  

  — 
  o-ooooi 
  

  

  (13) 
  

  

  8 
  

  

  0-01 
  

  

  0-65 
  

  

  0-00070 
  

  

  000069- 
  

  

  — 
  0-00001 
  

  

  14) 
  

   (15) 
  

  

  1 
  

  

  0-01 
  

  

  0-58 
  

  

  0-00061 
  

  

  0-00061 
  

  

  0-00000 
  

  

  6 
  

  

  0-008 
  

  

  0-51 
  

  

  00052 
  

  

  0-00054 
  

  

  + 
  0-00002 
  

  

  (16) 
  

  

  5 
  

  

  0-008 
  

  

  0-41 
  

  

  000043 
  

  

  0-00044 
  

  

  + 
  0-00001 
  

  

  (17) 
  

  

  4 
  

  

  0-005 
  

  

  0-35 
  

  

  0-00035 
  

  

  0-00037 
  

  

  + 
  0-00002 
  

  

  (18) 
  

  

  3 
  

  

  0-005 
  

  

  0-24 
  

  

  0-00026 
  

  

  0-00026 
  

  

  0-00000 
  

  

  (19) 
  

  

  2 
  

  

  0-003 
  

  

  0-21 
  

  

  0-00017 
  

  

  0-00022 
  

  

  + 
  0-00005 
  

  

  (20) 
  

  

  1 
  

  

  0-003 
  

  

  0-10 
  

  

  0-00009 
  

  

  0-00011 
  

  

  + 
  0-00002 
  

  

  