﻿214 
  Gooch 
  and 
  Gruener 
  — 
  Method 
  for 
  the 
  Determination 
  

  

  amount 
  of 
  antimonious 
  oxide 
  present 
  (with 
  excess 
  of 
  potas- 
  

   sium 
  iodide 
  and 
  10cm. 
  3 
  of 
  sulphuric 
  acid, 
  1 
  : 
  1) 
  was 
  approxi- 
  

   mately 
  0*2 
  grm. 
  Otherwise 
  the 
  process 
  as 
  employed 
  in 
  the 
  

   reduction 
  of 
  arsenic 
  appeared 
  to 
  be 
  applicable 
  to 
  the 
  similar 
  

   treatment 
  of 
  antimony. 
  

  

  The 
  following 
  quantitative 
  experiments 
  were 
  undertaken 
  to 
  

   discover 
  the 
  condition 
  of 
  concentration 
  best 
  suited 
  to 
  the 
  

   reduction 
  of 
  antimonic 
  salts 
  under 
  circumstances 
  otherwise 
  

   like 
  those 
  adapted 
  to 
  the 
  reduction 
  of 
  arsenic, 
  and 
  to 
  test 
  the 
  

   perfection 
  of 
  the 
  process. 
  Definite 
  amounts 
  of 
  tartar 
  emetic, 
  

   purified 
  by 
  recrystallization, 
  were 
  used 
  to 
  make 
  the 
  antimonic 
  

   salt 
  to 
  be 
  afterward 
  reduced, 
  the 
  antimony 
  being 
  raised 
  to 
  the 
  

   highest 
  degree 
  of 
  oxidation 
  by 
  titration 
  with 
  standard 
  iodine 
  

   after 
  the 
  addition 
  of 
  sodium 
  tartrate 
  (to 
  prevent 
  the 
  precipita- 
  

   tion 
  of 
  the 
  antimony 
  during 
  the 
  process 
  of 
  oxidation) 
  and 
  

   hydrogen 
  sodium 
  carbonate 
  in 
  the 
  usual 
  excess. 
  In 
  this 
  

   process 
  starch 
  was 
  sometimes 
  employed 
  to 
  give 
  the 
  end 
  reac- 
  

   tion, 
  and 
  sometimes 
  reliance 
  was 
  placed 
  upon 
  the 
  appearance 
  

   of 
  the 
  color 
  of 
  free 
  iodine, 
  experience 
  having 
  indicated 
  that 
  

   the 
  use 
  of 
  the 
  starch 
  is 
  not 
  essential 
  when 
  the 
  solutions 
  are 
  

   sufficiently 
  small 
  in 
  volume, 
  though 
  as 
  a 
  matter 
  of 
  course, 
  the 
  

   correction 
  demanded 
  for 
  the 
  excess 
  of 
  iodine 
  necessary 
  to 
  give 
  

   color 
  to 
  the 
  body 
  of 
  liquid 
  is 
  greater 
  w^hen 
  starch 
  is 
  not 
  used. 
  

  

  This 
  treatment 
  of 
  the 
  tartar 
  emetic 
  served 
  the 
  double 
  pur- 
  

   pose 
  of 
  providing 
  a 
  perfectly 
  definite 
  antimonic 
  salt 
  and 
  re- 
  

   standardizing 
  the 
  solution 
  of 
  standard 
  iodine, 
  which 
  was 
  to 
  be 
  

   used 
  subsequently 
  in 
  reoxidizing 
  the 
  antimony 
  after 
  its 
  reduc- 
  

   tion, 
  against 
  the 
  tartar 
  emetic 
  ; 
  and 
  thus 
  the 
  imperfection 
  of 
  

   the 
  process, 
  whatever 
  it 
  may 
  be, 
  whether 
  in 
  the 
  reduction 
  or 
  

   elsewhere, 
  becomes 
  apparent 
  and 
  is 
  measured 
  immediately 
  by 
  

   the 
  difference 
  between 
  the 
  amounts 
  of 
  iodine 
  employed 
  in 
  the 
  

   two 
  oxidations. 
  This 
  mode 
  of 
  standardizing 
  the 
  iodine 
  appears 
  

   to 
  be 
  peculiarly 
  advantageous 
  in 
  view 
  of 
  Fresenius's 
  demonstra- 
  

   tion* 
  that 
  the 
  iodometric 
  estimation 
  of 
  antimony 
  yields 
  too 
  

   high 
  results, 
  at 
  least 
  in 
  the 
  case 
  of 
  tartar 
  emetic, 
  when 
  the 
  

   standard 
  iodine 
  is 
  standardized 
  in 
  the 
  usual 
  manner 
  and, 
  as 
  is 
  

   undoubtedly 
  best, 
  the 
  characteristic 
  starch-blue 
  is 
  taken 
  for 
  

   the 
  end 
  reaction 
  rather 
  than 
  the 
  premonitory 
  and 
  somewhat 
  

   indefinite 
  reddish 
  tint. 
  

  

  The 
  larger 
  amounts 
  of 
  tartar 
  emetic 
  were 
  weighed 
  out 
  dry 
  ; 
  

   the 
  smaller 
  quantities 
  were 
  secured 
  by 
  measuring 
  out 
  definite 
  

   portions 
  of 
  a 
  solution 
  of 
  fixed 
  strength. 
  To 
  every 
  portion 
  was 
  

   added, 
  in 
  an 
  Erlenmeyer 
  beaker 
  of 
  300 
  cm. 
  3 
  capacity, 
  one 
  

   gram 
  of 
  tartaric 
  acid 
  previously 
  treated 
  with 
  an 
  excess 
  of 
  

   hydrogen 
  sodium 
  carbonate, 
  and 
  the 
  oxidation 
  was 
  effected, 
  as 
  

   described, 
  by 
  iodine 
  dissolved 
  in 
  potassium 
  iodide 
  to 
  a 
  solution 
  

  

  *Quaut. 
  Anal. 
  6 
  te 
  Aufl., 
  817. 
  

  

  