﻿Ions 
  from 
  Hot 
  Salts. 
  463 
  

  

  placed 
  at 
  the 
  centre 
  of 
  a 
  special 
  strip 
  from 
  which 
  a 
  little 
  

   piece 
  had 
  been 
  cut 
  away 
  on 
  each 
  side 
  of 
  the 
  salt, 
  which 
  thus 
  

   Jay 
  on 
  an 
  expansion 
  between 
  two 
  slightly 
  narrower 
  necks. 
  

   It 
  was 
  expected 
  that 
  this 
  would 
  keep 
  the 
  salt 
  at 
  a 
  uniform 
  

   temperature 
  and, 
  what 
  is 
  more 
  important, 
  tend 
  to 
  keep 
  it 
  

  

  Fisr. 
  2. 
  

  

  40 
  

  

  !| 
  

  

  I* 
  

  

  5*^ 
  10 
  

  

  ii) 
  !! 
  

  

  

  

  - 
  r 
  .i?0*IS- 
  / 
  

  

  

  ^ 
  1 
  

  

  L' 
  n 
  

  

  ■*? 
  

  

  s* 
  

  

  1 
  

  

  

  

  s* 
  

  

  ^~~^r7 
  

  

  'Y 
  Ions 
  

  

  ONLY- 
  

  

  ' 
  1 
  

   1 
  

  

  -40 
  -80 
  -120 
  -160 
  -200 
  

  

  PCTENT/ZIL 
  D/FF£/?EjVC£-yOLTS. 
  

  

  from 
  flowing 
  towards 
  the 
  ends 
  of 
  the 
  strip. 
  Most 
  of 
  these 
  

   salts 
  seem 
  to 
  have 
  a 
  tendency 
  to 
  flow 
  on 
  to 
  the 
  cooler 
  parts 
  

   of 
  the 
  hot 
  metal. 
  In 
  the 
  present 
  case 
  the 
  salt 
  was 
  bounded 
  

   on 
  both 
  sides 
  by 
  the 
  slightly 
  narrower, 
  and 
  therefore 
  hotter, 
  

   portions 
  and 
  would 
  thus 
  tend 
  to 
  remain 
  where 
  it 
  was 
  placed. 
  

   It 
  is 
  important 
  that 
  salt 
  should 
  not 
  be 
  present 
  near 
  the 
  ends 
  

   of 
  the 
  strip. 
  For 
  if 
  it 
  is, 
  fresh 
  salt 
  is 
  constantly 
  being- 
  

   brought 
  into 
  play 
  as 
  the 
  temperature 
  of 
  the 
  strip 
  is 
  raised, 
  

   owing 
  to 
  the 
  hot 
  region 
  extending 
  closer 
  to 
  the 
  cold 
  terminals. 
  

   Moreover, 
  the 
  different 
  portions 
  of 
  the 
  salt 
  are 
  not 
  all 
  at 
  the 
  

   same 
  temperature 
  and, 
  what 
  makes 
  matters 
  worse, 
  the 
  salt 
  

   flows 
  about, 
  so 
  that 
  its 
  temperature 
  distribution 
  changes 
  

   from 
  time 
  to 
  time. 
  So 
  far 
  as 
  I 
  have 
  been 
  able 
  to 
  judge, 
  

   these 
  difficulties 
  are 
  overcome 
  by 
  the 
  device 
  which 
  has 
  

   been 
  described. 
  With 
  this 
  arrangement 
  the 
  resistance 
  of 
  

   the 
  strip 
  was 
  only 
  used 
  as 
  an 
  intermediate 
  indication 
  of 
  the 
  

   temperature 
  of 
  the 
  salt. 
  The 
  temperature 
  of 
  the 
  salt 
  was 
  

   finally 
  obtained 
  by 
  placing 
  specks 
  of 
  sodium 
  chloride 
  and 
  of 
  

   zinc 
  at 
  the 
  place 
  where 
  the 
  salt 
  had 
  been 
  and 
  observing 
  the 
  

   resistance 
  of 
  the 
  strip 
  at 
  which 
  the 
  specks 
  just 
  melted. 
  From 
  

   these 
  fiducial 
  points 
  and 
  the 
  resistance 
  at 
  the 
  temperature 
  of 
  

   the 
  laboratory 
  a 
  curve 
  was 
  constructed 
  giving 
  the 
  actual 
  

   centigrade 
  temperature 
  of 
  the 
  salt 
  in 
  terms 
  of 
  the 
  corre- 
  

   sponding 
  resistance 
  of 
  the 
  strip. 
  

  

  The 
  results 
  of 
  some 
  of 
  these 
  experiments 
  are 
  exhibited 
  

  

  2 
  I 
  2 
  

  

  