﻿464 
  

  

  Prof. 
  0. 
  W. 
  Richardson 
  on 
  the 
  

  

  graphically 
  in 
  figs. 
  3, 
  4, 
  and 
  5. 
  In 
  each 
  case 
  a 
  fresh 
  sample 
  

   of 
  salt 
  was 
  used 
  and 
  approximately 
  the 
  same 
  amount 
  was 
  

   taken. 
  The 
  currents 
  are 
  smaller 
  than 
  those 
  already 
  recorded 
  

   for 
  the 
  same 
  temperature. 
  This 
  is 
  partly 
  owing 
  to 
  the 
  much 
  

   smaller 
  area 
  of 
  the 
  salt 
  used. 
  The 
  temperature 
  was 
  adjusted 
  

   and 
  measured 
  as 
  quickly 
  as 
  possible, 
  a 
  process 
  which 
  generally 
  

   occupied 
  about 
  one 
  minute, 
  and 
  then 
  alternate 
  readings 
  were 
  

   taken 
  with 
  the 
  magnetic 
  field 
  on 
  and 
  off. 
  

  

  In 
  each 
  case 
  the 
  current 
  rose 
  to 
  a 
  maximum 
  in 
  about 
  15 
  

   minutes 
  and 
  then 
  decayed 
  more 
  slowly 
  than 
  it 
  had 
  risen. 
  

   Fig. 
  3 
  shows 
  the 
  results 
  obtained 
  at 
  the 
  lowest 
  temperature 
  

   (523° 
  C). 
  The 
  currents 
  in 
  this 
  case 
  are 
  quite 
  small 
  and 
  

  

  Fig. 
  3. 
  

  

  160 
  

  

  30 
  45 
  60 
  75 
  

  

  Tjme 
  heated 
  in 
  Minutes. 
  

  

  Fig:. 
  4. 
  

  

  120 
  

  

  30 
  45 
  60 
  75 
  

  

  77 
  me 
  in 
  Minutes 
  

  

  there 
  is 
  no 
  detectable 
  difference 
  at 
  any 
  stage 
  between 
  the 
  

   current 
  when 
  the 
  stopping 
  field 
  is 
  on 
  and 
  when 
  it 
  is 
  off. 
  

   This 
  confirms 
  our 
  previous 
  conclusion 
  that 
  at 
  low 
  tempe- 
  

   ratures, 
  or 
  at 
  any 
  rate 
  when 
  the 
  fresh 
  salt 
  is 
  giving 
  a 
  small 
  

   emission, 
  the 
  entire 
  current 
  is 
  carried 
  by 
  heavy 
  ions. 
  

  

  Fig. 
  4 
  shows 
  the 
  results 
  obtained 
  ;it 
  a 
  slightly 
  higher 
  

  

  