﻿Ions 
  from 
  Hot 
  Salts. 
  455 
  

  

  Cadmium 
  Iodide. 
  Cdl 
  2 
  . 
  

  

  The 
  results 
  of 
  a 
  series 
  of 
  experiments 
  with 
  this 
  substance 
  

   using 
  the 
  balance 
  method 
  are 
  shown 
  graphically 
  in 
  fig. 
  1. 
  

   Values 
  of 
  the 
  electric 
  molecular 
  weight 
  ???/H 
  are 
  plotted 
  

   vertically 
  against 
  the 
  time 
  of 
  heating 
  in 
  minutes 
  as 
  abscissae. 
  

  

  Fisr. 
  1. 
  

  

  m./ 
  

  

  30 
  

  

  20 
  

  

  

  

  

  Cadm 
  

  

  IUM 
  lOD-DE 
  

  

  Cdl 
  e 
  . 
  

  

  

  

  Cd 
  ++ 
  

  

  \ 
  

  

  

  

  \ 
  X 
  

  

  K 
  

  

  

  

  

  

  

  

  

  

  iD 
  

  

  

  c 
  

  

  * 
  X 
  

  

  * 
  x 
  x 
  

  

  

  

  

  

  

  

  

  F 
  

  

  5 
  

  

  

  

  

  

  \ 
  NoL 
  4- 
  

  

  * 
  

  

  

  

  E* 
  x 
  

  

  

  100 
  

  

  200 
  300 
  

  

  T/ME 
  IN 
  MINUTES. 
  

  

  400 
  

  

  50-; 
  

  

  In 
  order 
  to 
  get 
  a 
  sufficiently 
  large 
  thermionic 
  current 
  to 
  

   determine 
  the 
  balance 
  point 
  satisfactorily, 
  it 
  was 
  necessary 
  

   to 
  raise 
  the 
  temperature 
  of 
  the 
  strip 
  from 
  time 
  to 
  time 
  on 
  

   account 
  of 
  the 
  decay 
  of 
  the 
  emission. 
  The 
  corresponding 
  

   platinum 
  resistance 
  temperatures 
  of 
  the 
  strip 
  are 
  set 
  out 
  near 
  

   the 
  bottom 
  of 
  the 
  diagram. 
  The 
  experimental 
  values 
  of 
  

   ??i/H 
  are 
  shown 
  thus: 
  — 
  x. 
  The 
  horizontal 
  lines 
  AB, 
  CD, 
  EF 
  

   represent 
  the 
  chemical 
  equivalent 
  weights 
  of 
  the 
  ions 
  Cd 
  ++ 
  , 
  

   K 
  + 
  , 
  and 
  Na 
  + 
  . 
  The 
  experimental 
  points 
  follow 
  the 
  line 
  AB 
  

   at 
  first, 
  then 
  break 
  sharply 
  to 
  CD, 
  and 
  afterwards 
  there 
  is 
  

   another 
  sharp 
  break 
  to 
  EF. 
  The 
  distance 
  of 
  the 
  points 
  from 
  

   the 
  curves 
  ABCDEF 
  is 
  never 
  greater 
  than 
  the 
  possible 
  error 
  

   of 
  measurements. 
  Thus 
  all 
  the 
  positive 
  ions 
  from 
  cadmium 
  

   iodide 
  are 
  accounted 
  for 
  by 
  supposing 
  that 
  there 
  is 
  an 
  

   emission 
  of 
  Cd 
  ++ 
  , 
  lasting 
  in 
  this 
  case 
  for 
  about 
  2 
  hours 
  ; 
  this 
  

   is 
  followed 
  by 
  K 
  + 
  and 
  Na 
  + 
  in 
  turn. 
  The 
  last 
  two 
  ions 
  are 
  

   presumably 
  due 
  to 
  alkaline 
  impurities 
  present 
  in 
  the 
  salt. 
  

   There 
  is 
  no 
  evidence 
  of 
  the 
  occurrence 
  of 
  the 
  monovalent 
  

   ion 
  Cd 
  + 
  . 
  Thus 
  the 
  behaviour 
  of 
  the 
  iodides 
  of 
  zinc 
  and 
  

   cadmium 
  is 
  very 
  similar 
  in 
  this 
  respect. 
  

  

  