﻿Oxides 
  and 
  Sulphides 
  of 
  Iron, 
  etc. 
  65 
  

  

  Cadmium 
  5*000 
  6*002 
  4*000 
  grams 
  

  

  " 
  not 
  burned 
  031V 
  1*329 
  0*106 
  

  

  " 
  burned 
  (a) 
  4*683 
  4*673 
  3*894 
  

  

  Sulphur 
  1*000 
  1*000 
  1*000 
  

  

  Sodium 
  peroxide 
  15* 
  18* 
  14* 
  

  

  Water 
  equivalent 
  of 
  system... 
  3*099 
  3*116 
  3*057 
  

  

  Temperature 
  interval 
  2*338 
  2*285 
  2*219° 
  

  

  Heateffect 
  7247 
  7120 
  6783 
  c 
  

  

  " 
  " 
  of 
  sulphur 
  5270 
  5270 
  5270 
  

  

  " 
  " 
  "iron 
  50 
  40 
  40 
  

  

  " 
  " 
  " 
  Cd 
  burned 
  (5).,. 
  1927 
  1810 
  1473 
  

  

  " 
  " 
  " 
  1 
  ffram 
  Cd- 
  411 
  387 
  378 
  

  

  a 
  

  

  The 
  difference 
  between 
  the 
  highest 
  and 
  lowest 
  result 
  for 
  1 
  gram 
  

   of 
  cadmium 
  is 
  large, 
  but 
  this 
  difference 
  of 
  33 
  c 
  is, 
  on 
  the 
  con- 
  

   trary, 
  small 
  when 
  we 
  consider 
  the 
  total 
  heat 
  effect 
  of 
  the 
  

   experiments. 
  The 
  mean 
  of 
  the 
  results 
  is 
  392 
  c 
  and 
  for 
  1 
  gram 
  

   atom 
  of 
  cadmium 
  reacting 
  with 
  sodium 
  peroxide 
  it 
  is 
  

   392 
  X 
  112*4 
  = 
  44,100 
  c 
  . 
  

  

  The 
  fusions 
  were 
  yellow 
  and 
  it 
  might 
  be 
  supposed 
  that 
  the 
  

   color 
  was 
  due 
  to 
  a 
  small 
  quantity 
  of 
  cadmium 
  sulphide. 
  

   When, 
  however, 
  a 
  mixture 
  of 
  cadmium 
  and 
  sodium 
  peroxide 
  

   was 
  heated 
  in 
  a 
  porcelain 
  crucible, 
  a 
  yellow 
  product 
  resulted. 
  

   The 
  fusions 
  in 
  the 
  bomb 
  disintegrated 
  slowly 
  in 
  cold 
  water 
  and 
  

   gave 
  off 
  oxygen 
  and 
  yielded 
  cadmium 
  hydroxide. 
  The 
  latter 
  

   was 
  dissolved 
  by 
  cautiously 
  adding 
  hydrochloric 
  acid 
  and 
  the 
  

   metallic 
  cadmium 
  remaining 
  was 
  washed, 
  dried 
  and 
  the 
  

   weight 
  of 
  it 
  deducted 
  from 
  the 
  metal 
  taken. 
  

  

  Yery 
  thin 
  lathe 
  turnings 
  of 
  cadmium 
  for 
  combustion 
  in 
  

   oxygen 
  gained 
  weight 
  slowly 
  in 
  the 
  air. 
  It 
  was 
  found 
  that 
  

   21*816 
  grams 
  increased 
  2 
  mg 
  in 
  a 
  few 
  hours 
  in 
  the 
  air 
  and 
  2 
  rag 
  

   more 
  on 
  standing 
  48 
  hours 
  in 
  a 
  desiccator. 
  These 
  figures 
  of 
  

   course 
  do 
  not 
  represent 
  the 
  total 
  oxidation 
  of 
  the 
  metal. 
  The 
  

   slight 
  amount, 
  however, 
  does 
  not 
  affect 
  the 
  result, 
  which 
  is 
  cal- 
  

   culated 
  from 
  the 
  weight 
  of 
  oxygen 
  taken 
  up 
  by 
  the 
  metal 
  

   when 
  burned. 
  The 
  following 
  method 
  was 
  used 
  in 
  the 
  deter- 
  

   mination 
  : 
  Cotton 
  was 
  placed 
  in 
  the 
  bottom 
  of 
  a 
  600 
  cc 
  bomb 
  

   and 
  a 
  loose 
  string 
  of 
  the 
  cotton 
  was 
  drawn 
  up 
  so 
  that 
  it 
  extended 
  

   above 
  the 
  bulky 
  bunch 
  of 
  turnings. 
  The 
  ignition 
  was 
  by 
  

   means 
  of 
  a 
  fine 
  cotton 
  thread 
  attached 
  to 
  a 
  wire 
  connecting 
  the 
  

   electrodes. 
  The 
  object 
  of 
  placing 
  the 
  bulk 
  of 
  the 
  cotton 
  below 
  

   the 
  turnings 
  was 
  to 
  blow 
  the 
  metal 
  away 
  from 
  the 
  cold 
  bot- 
  

   tom 
  of 
  the 
  bomb. 
  After 
  a 
  combustion 
  the 
  contents 
  of 
  the 
  

   bomb 
  were 
  shaken 
  out, 
  collected 
  in 
  a 
  crucible, 
  warmed 
  gently 
  

   two 
  or 
  more 
  times 
  until 
  the 
  weight 
  remained 
  constant. 
  Next 
  

   the 
  bomb 
  was 
  rinsed 
  with 
  water 
  to 
  remove 
  the 
  cadmium 
  oxide 
  

  

  Am. 
  Joub. 
  Sci.— 
  Fourth 
  Series, 
  Vol. 
  XXXVI, 
  No. 
  211.— 
  July, 
  1913. 
  

   5 
  

  

  