﻿Brovjnwg 
  — 
  Volumetric 
  Estimation 
  of 
  Cerium. 
  457 
  

  

  indication 
  of 
  hydrogen 
  dioxide. 
  The 
  moist 
  precipitate 
  was 
  

   then 
  washed 
  into 
  a 
  beaker, 
  one 
  gram 
  of 
  potassium 
  iodide 
  added 
  

   and 
  10°°^^ 
  of 
  strong 
  HCl. 
  The 
  precipitate 
  dissolved 
  quite 
  

   readily 
  in 
  the 
  cold 
  and 
  the 
  iodine 
  liberated 
  was 
  determined 
  by 
  

   standard 
  sodium 
  thiosulphate. 
  The 
  results 
  appear 
  in 
  Table 
  V. 
  

  

  

  

  Table 
  Y. 
  

  

  

  

  CeOs 
  taken. 
  

  

  CeOa 
  found. 
  

  

  Error. 
  

  

  

  grm. 
  

  

  grm. 
  

  

  grm. 
  

  

  (') 
  

  

  0-1142 
  

  

  0-1140 
  

  

  0-0002- 
  

  

  (2) 
  

  

  0-1142 
  

  

  0-1147 
  

  

  0-0005 
  + 
  

  

  (3) 
  

  

  0-1142 
  

  

  0-1152 
  

  

  0-0010 
  + 
  

  

  (S) 
  

  

  0-1142 
  

  

  01159 
  

  

  0-0017 
  + 
  

  

  (5) 
  

  

  0-1142 
  

  

  0-1152 
  

  

  0-0010 
  + 
  

  

  (6) 
  

  

  0-1142 
  

  

  0-1156 
  

  

  0-0014 
  + 
  

  

  Another 
  series 
  of 
  these 
  precipitates 
  prepared 
  in 
  the 
  same 
  

   way 
  was 
  boiled 
  with 
  a 
  definite 
  amount 
  of 
  arsenious 
  acid 
  in 
  acid 
  

   solution, 
  as 
  previously 
  described 
  in 
  the 
  case 
  of 
  the 
  ignited 
  

   dioxide. 
  The 
  results 
  which 
  are 
  recorded 
  in 
  Table 
  YI 
  show, 
  as 
  

   in 
  the 
  case 
  of 
  the 
  ignited 
  dioxide, 
  an 
  insufficient 
  reduction 
  of 
  

   the 
  cerium 
  by 
  the 
  arsenious 
  acid. 
  

  

  

  

  Table 
  YI. 
  

  

  

  

  CeOa 
  taken. 
  

  

  CeO.2 
  found. 
  

  

  Error. 
  

  

  

  grm. 
  

  

  grm. 
  

  

  grm. 
  

  

  (0 
  

  

  0-0381 
  

  

  0-0370 
  

  

  0-0011- 
  

  

  (2) 
  

  

  0-0381 
  

  

  0-0361 
  

  

  0-0020- 
  

  

  (3) 
  

  

  0-1142 
  

  

  0-1077 
  

  

  0-0064 
  — 
  

  

  (4) 
  

  

  0-1060 
  

  

  0-1002 
  

  

  0-0058 
  — 
  

  

  The 
  Estimation 
  of 
  Ceriiun 
  Oxalatehy 
  Potassium 
  Perinanga^iate 
  — 
  

   (with 
  Leo 
  A. 
  Lynch). 
  

  

  Stolba^ 
  has 
  stated 
  that 
  cerium 
  oxalate 
  may 
  be 
  estimated 
  

   volumetrically 
  after 
  the 
  same 
  manner 
  as 
  calcium 
  oxalate 
  by 
  

   treating 
  the 
  washed 
  precipitate, 
  suspended 
  in 
  warm 
  water, 
  to 
  

   which 
  a 
  moderate 
  amount 
  of 
  sulphuric 
  acid 
  has 
  been 
  added, 
  

   by 
  potassium 
  permanganate. 
  As 
  the 
  titration 
  proceeds 
  the 
  

   precipitate 
  disappears 
  and 
  the 
  end 
  reaction 
  is 
  sharp. 
  He 
  also 
  

   finds 
  that 
  the 
  permanganate 
  does 
  not 
  oxidize 
  the 
  cerium 
  from 
  

   the 
  lower 
  to 
  the 
  higlier 
  condition. 
  So 
  far 
  as 
  we 
  have 
  been 
  

   able 
  to 
  discover, 
  no 
  experimental 
  evidence 
  has 
  been 
  presented 
  

   to 
  prove 
  the 
  correctness 
  of 
  Stolba's 
  statement, 
  and 
  the 
  work 
  

   to 
  be 
  described 
  was 
  undertaken 
  to 
  furnish 
  such 
  evidence. 
  

  

  * 
  Sitzungsber. 
  d. 
  kgl. 
  bohm. 
  Gesellsch. 
  d. 
  Wissenschaften 
  v. 
  4 
  Juli, 
  1879; 
  

   Zeitschr 
  fiir 
  Anal. 
  Chem 
  , 
  xix, 
  194. 
  

  

  