﻿of 
  Antimony 
  and 
  its 
  condition 
  of 
  Oxidation. 
  219 
  

  

  cess 
  outlined 
  and 
  determinable 
  with 
  accuracy 
  by 
  titration 
  with 
  

   iodine 
  standardized 
  against 
  arsenious 
  oxide. 
  In 
  this 
  later 
  

   work 
  we 
  show 
  that 
  antimony 
  may 
  be 
  reduced 
  similarly 
  and 
  

   • 
  estimated 
  satisfactorily 
  by 
  titration 
  against 
  iodine 
  standardized 
  

   against 
  tartar 
  emetic. 
  These 
  two 
  methods 
  of 
  standardizing 
  do 
  

   not 
  yield 
  identical 
  results, 
  and 
  so 
  we 
  are 
  confronted 
  with 
  an 
  

   inherent 
  error 
  in 
  the 
  process 
  for 
  estimating 
  antimony 
  and- 
  

   arsenic 
  at 
  once, 
  which 
  cannot 
  be 
  overcome 
  unless 
  the 
  individ- 
  

   ual 
  amount 
  of 
  one 
  or 
  other 
  constituent 
  may 
  be 
  otherwise 
  

   determined. 
  If 
  the 
  determination 
  of 
  either 
  the 
  arsenic 
  or 
  

   antimony 
  is 
  possible 
  it 
  is, 
  of 
  course, 
  easy 
  to 
  calculate 
  with 
  the 
  

   use 
  of 
  the 
  appropriate 
  standard 
  the 
  amount 
  of 
  the 
  solution 
  of 
  

   iodine 
  which 
  is 
  really 
  engaged 
  in 
  the 
  oxidation 
  of 
  this 
  particu- 
  

   lar 
  constituent, 
  and 
  the 
  remainder 
  of 
  the 
  iodine 
  actually 
  em- 
  

   ployed, 
  gauged 
  by 
  the 
  second 
  standard, 
  will 
  give 
  the 
  corrected 
  

   amount 
  of 
  the 
  second 
  constituent. 
  

  

  In 
  case 
  no 
  such 
  correction 
  is 
  feasible 
  it 
  becomes 
  a 
  matter 
  of 
  

   interest 
  to 
  note 
  the 
  magnitude 
  of 
  possible 
  error. 
  Our 
  experi- 
  

   ence, 
  based 
  upon 
  many 
  determinations 
  throughout 
  the 
  course 
  

   of 
  the 
  work 
  detailed 
  above, 
  pointed 
  to 
  a 
  difference 
  in 
  the 
  

   value 
  of 
  the 
  two 
  standards 
  amounting 
  to 
  about 
  one-half 
  of 
  one 
  

   per 
  cent. 
  If, 
  therefore, 
  the 
  weight 
  of 
  reduced 
  oxide 
  amounts 
  

   to 
  the 
  maximum 
  which 
  we 
  have 
  experimented 
  with 
  — 
  about 
  

   0*2 
  grm. 
  — 
  the 
  greatest 
  possible 
  error 
  will 
  be 
  0*0010 
  grm.+ 
  or 
  

   0*0010 
  grm. 
  — 
  , 
  according 
  as 
  the 
  entire 
  0*2 
  grm. 
  is 
  antimonious 
  

   oxide 
  estimated 
  by 
  the 
  arsenic 
  standard, 
  or 
  arsenious 
  oxide 
  

   estimated 
  by 
  the 
  tartar 
  emetic 
  standard. 
  The 
  essential 
  features 
  

   of 
  the 
  process 
  which 
  we 
  propose 
  for 
  the 
  reduction 
  of 
  antimony 
  

   and 
  the 
  determination 
  of 
  its 
  degree 
  of 
  oxidation 
  are 
  recapitu- 
  

   lated 
  briefly 
  in 
  the 
  following 
  statement. 
  

  

  The 
  salt 
  of 
  antimony, 
  not 
  exceeding 
  the 
  equivalent 
  of 
  about 
  

   0*2 
  grm. 
  of 
  antimonious 
  oxide, 
  is 
  titrated, 
  in 
  presence 
  of 
  1 
  grm. 
  

   of 
  sodium 
  tartrate 
  and 
  the 
  usual 
  excess 
  of 
  sodium 
  hydrogen 
  

   carbonate, 
  by 
  means 
  of 
  iodine 
  standardized 
  against 
  tartar 
  

   emetic. 
  The 
  result 
  of 
  this 
  titration 
  gives 
  the 
  amount 
  of 
  

   antimonious 
  salt 
  present. 
  To 
  the 
  solution 
  are 
  then 
  added 
  

   4: 
  grms. 
  of 
  tartaric, 
  dilute 
  sulphuric 
  acid, 
  if 
  necessary, 
  to 
  

   neutralization, 
  an 
  excess 
  of 
  10 
  cm. 
  3 
  of 
  half 
  and 
  half 
  sulphuric 
  

   acid, 
  and 
  enough 
  potassium 
  iodide 
  so 
  that 
  there 
  shall 
  be 
  

   present 
  of 
  hydriodic 
  acid 
  the 
  equivalent 
  of 
  a 
  little 
  more 
  than 
  

   1 
  grm. 
  of 
  the 
  iodide. 
  The 
  liquid 
  is 
  diluted 
  to 
  100 
  cm. 
  3 
  , 
  boiled 
  

   in 
  an 
  Erlenmeyer 
  beaker 
  until 
  the 
  volume 
  is 
  decreased 
  to 
  

   50 
  cm. 
  3 
  , 
  the 
  precaution 
  being 
  taken 
  to 
  introduce 
  a 
  platinum 
  

   spiral 
  to 
  prevent 
  bumping 
  and 
  a 
  trap, 
  as 
  described, 
  to 
  obviate 
  

   mechanical 
  loss. 
  The 
  color 
  remaining 
  after 
  concentration, 
  if 
  

   there 
  be 
  any, 
  is 
  bleached 
  by 
  dilute 
  sulphurous 
  acid 
  (approxi- 
  

   mately 
  centinormal). 
  The 
  solution 
  is 
  nearly 
  neutralized 
  with 
  

  

  