﻿110 
  

  

  Mr. 
  G. 
  F. 
  Rodwell 
  on 
  the 
  

  

  [Dec. 
  10, 
  

  

  the 
  liquid 
  mass 
  is 
  above 
  the 
  point 
  at 
  which 
  the 
  vapour 
  ignites 
  spontane- 
  

   ously. 
  It 
  is 
  also 
  difficult 
  to 
  manipulate 
  with 
  a 
  liquid 
  which 
  is 
  above 
  the 
  

   boiling-point 
  of 
  mercury, 
  and 
  is 
  at 
  the 
  same 
  time 
  giving 
  off 
  clouds 
  of 
  

   spontaneously 
  inflammable 
  vapour. 
  The 
  slight 
  conductivity 
  of 
  the 
  solid 
  

   is 
  shown 
  by 
  the 
  following 
  results. 
  The 
  bulb 
  of 
  a 
  thermometer 
  was 
  im- 
  

   bedded 
  in 
  a 
  mass 
  of 
  paraffine 
  in 
  such 
  a 
  manner 
  that 
  the 
  distance 
  between 
  

   the 
  outer 
  surface 
  of 
  the 
  paraffine 
  and 
  the 
  surface 
  of 
  the 
  bulb 
  was 
  8 
  millims. 
  

   (about 
  y 
  5 
  ^ 
  inch). 
  It 
  was 
  immersed 
  in 
  water, 
  and 
  kept 
  in 
  a 
  fixed 
  position 
  

   about 
  3 
  centimetres 
  above 
  the 
  bottom 
  of 
  the 
  beaker, 
  and 
  on 
  a 
  level 
  with 
  a 
  

   thermometer-bulb 
  in 
  direct 
  contact 
  with 
  the 
  water. 
  The 
  beaker 
  was 
  

   gently 
  heated 
  on 
  a 
  sand-bath, 
  and 
  the 
  thermometers 
  were 
  observed 
  for 
  

   nearly 
  an 
  hour 
  at 
  intervals 
  of 
  two 
  minutes. 
  At 
  starting, 
  11.20 
  a.m., 
  the 
  

   temperature 
  of 
  the 
  water 
  was 
  52° 
  F. 
  (11°-11 
  C). 
  The 
  gas 
  was 
  turned 
  

  

  Time. 
  

  

  Temperature 
  shown 
  by 
  

   the 
  thermometer 
  

   immersed, 
  in 
  water. 
  

  

  Temperature 
  shown 
  by 
  

  

  the 
  thermometer 
  

   imbedded 
  in 
  paraffine. 
  

  

  Difference. 
  

  

  h 
  m 
  

  

  

  

  

  11 
  20a.m. 
  

  

  52° 
  F. 
  

  

  52° 
  F. 
  

  

  0° 
  F. 
  

  

  11 
  22 
  

  

  68 
  

  

  54 
  

  

  — 
  14 
  

  

  11 
  24 
  

  

  85 
  

  

  58 
  

  

  — 
  27 
  

  

  11 
  26 
  

  

  105 
  

  

  67 
  

  

  — 
  38 
  

  

  11 
  28 
  

  

  124 
  

  

  70 
  

  

  — 
  45 
  

  

  11 
  30 
  

  

  141 
  

  

  92 
  

  

  — 
  69 
  

  

  11 
  32 
  

  

  148 
  

  

  1 
  00 
  

  

  — 
  48 
  

  

  11 
  34 
  

  

  148 
  

  

  

  — 
  40*5 
  

  

  11 
  36 
  

  

  146 
  

  

  112 
  

  

  — 
  34 
  

  

  11 
  38 
  

  

  144 
  

  

  116-5 
  

  

  -27-5 
  

  

  11 
  40 
  

  

  141-5 
  

  

  120-5 
  

  

  — 
  21 
  

  

  11 
  42 
  

  

  139 
  

  

  124 
  

  

  -15 
  

  

  11 
  44 
  

  

  137 
  

  

  127 
  

  

  -10 
  

  

  11 
  46 
  

  

  134 
  

  

  129 
  

  

  — 
  5 
  

  

  11 
  48 
  

  

  131 
  

  

  130 
  

  

  - 
  1 
  

  

  11 
  50 
  

  

  129-5 
  

  

  130 
  

  

  + 
  0-5 
  

  

  11 
  52 
  

  

  128 
  

  

  130 
  

  

  + 
  2 
  

  

  11 
  54 
  

  

  126 
  

  

  129 
  

  

  + 
  3 
  

  

  11 
  56 
  

  

  124 
  

  

  128 
  

  

  + 
  4 
  

  

  11 
  58 
  

  

  122 
  

  

  126 
  

  

  + 
  4 
  

  

  12 
  00 
  

  

  120 
  

  

  124-5 
  

  

  + 
  4-5 
  

  

  12 
  2 
  p.m. 
  

  

  118 
  

  

  • 
  122 
  

  

  + 
  4 
  

  

  12 
  4 
  

  

  116-5 
  

  

  120-5 
  

  

  + 
  4 
  

  

  12 
  6 
  

  

  115-5 
  

  

  119-5 
  

  

  + 
  4 
  

  

  12 
  8 
  

  

  114 
  

  

  118-25 
  

  

  + 
  4-25 
  

  

  12 
  10 
  

  

  112-5 
  

  

  117-25 
  

  

  * 
  4-75 
  

  

  12 
  22 
  

  

  105 
  

  

  111-25 
  

  

  

  12 
  47 
  

  

  90-5 
  

  

  90-5 
  

  

  

  1 
  6 
  

  

  82-5 
  

  

  82-5 
  

  

  

  2 
  14 
  

  

  66-5 
  

  

  66-5 
  

  

  

  