﻿Organic 
  Liquids 
  in 
  Presence 
  of 
  Dust-free 
  Air. 
  309 
  5 
  

  

  effectively 
  adiabatic 
  expansion 
  in 
  {%). 
  For 
  comparative 
  

   purposes, 
  however, 
  this 
  source 
  of 
  uncertainty 
  is 
  of 
  no 
  

   account. 
  As 
  pointed 
  out 
  by 
  Wilson 
  and 
  confirmed 
  by 
  

   myself, 
  differences 
  of 
  two 
  or 
  three 
  degrees 
  are 
  practically 
  

   without 
  influence 
  on 
  the 
  results, 
  so 
  that 
  the 
  differences 
  recorded 
  

   in 
  the 
  last 
  column 
  do 
  not 
  materially 
  affect 
  the 
  comparison. 
  

  

  A 
  more 
  important 
  point 
  is 
  the 
  fact 
  that, 
  owing 
  to 
  differ- 
  

   ences 
  in 
  the 
  vapour-pressures 
  of 
  the 
  liquids, 
  a 
  proper 
  

   comparison 
  would 
  require 
  the 
  calculation 
  of 
  the 
  degree 
  of 
  

   supersaturation 
  in 
  each 
  case, 
  not 
  simply 
  the 
  expansion-ratio. 
  

   This 
  calculation 
  seems 
  to 
  me 
  to 
  be 
  very 
  uncertain, 
  as 
  it 
  

   requires 
  the 
  assumption 
  that 
  the 
  supersaturated 
  vapour 
  obeys 
  

   the 
  simple 
  gas 
  laws. 
  By 
  comparing 
  liquids 
  of 
  such 
  very 
  

   different 
  volatilities 
  as 
  say 
  carbon 
  tetrachloride, 
  benzene, 
  and 
  

   chlorobenzene, 
  this 
  difficulty 
  can 
  be 
  more 
  or 
  less 
  obviated 
  so 
  

   far 
  as 
  a 
  qualitative 
  comparison 
  is 
  concerned. 
  

  

  Without 
  going 
  into 
  fine 
  distinctions, 
  the 
  above 
  results 
  on 
  

   a 
  cursory 
  examination 
  seem 
  to 
  justify 
  the 
  conclusion 
  that 
  

   condensation 
  takes 
  place 
  with 
  greater 
  difficulty 
  in 
  the 
  case 
  of 
  

   non-ionizing 
  solvents. 
  The 
  case 
  of 
  carbon 
  disulphide 
  is, 
  

   however, 
  very 
  peculiar. 
  An 
  extremely 
  small 
  degree 
  of 
  ex- 
  

   pansion 
  appeared 
  to 
  produce 
  condensation 
  in 
  this 
  case, 
  and 
  

   scarcely 
  any 
  region 
  of 
  increasing 
  expansion 
  and 
  rain-like 
  con- 
  

   densation 
  appeared 
  to 
  exist. 
  And, 
  so 
  far 
  as 
  I 
  know, 
  it 
  does 
  

   not 
  act 
  as 
  an 
  ionizing 
  solvent. 
  This 
  cannot 
  be 
  due 
  to 
  its 
  

   greater 
  volatility, 
  as 
  a 
  comparison 
  with 
  carbon 
  tetrachloride 
  

   shows*. 
  

  

  On 
  the 
  other 
  hand, 
  experiments 
  with 
  acetone, 
  whose 
  results 
  

   I 
  have 
  not 
  included 
  in 
  the 
  table, 
  as 
  the 
  vapour- 
  pressure 
  data 
  

   for 
  pure 
  acetone 
  do 
  not 
  appear 
  to 
  be 
  known 
  with 
  sufficient 
  

   certainty, 
  showed 
  conclusively 
  that 
  it 
  required 
  an 
  extremely 
  

   high 
  expansion-ratio 
  to 
  produce 
  even 
  rain-like 
  condensation, 
  

   and 
  yet 
  acetone 
  may 
  be 
  classed 
  with 
  ethyl 
  and 
  methyl 
  alcohols 
  

   as 
  a 
  solvent 
  of 
  moderate 
  ionizing 
  power. 
  

  

  Under 
  these 
  circumstances 
  I 
  do 
  not 
  feel 
  entitled 
  to 
  draw 
  

   any 
  certain 
  conclusion 
  from 
  the 
  above 
  experiments. 
  They 
  

   seemed, 
  however, 
  to 
  be 
  of 
  sufficient 
  interest 
  to 
  warrant 
  publica- 
  

   tion, 
  owing 
  to 
  the 
  importance 
  which 
  attaches 
  at 
  the 
  present 
  

   time 
  to 
  the 
  new 
  theories 
  which 
  are 
  being 
  developed 
  in 
  con- 
  

   nexion 
  with 
  the 
  question 
  of 
  electrical 
  nuclei 
  in 
  gases. 
  

  

  In 
  conclusion 
  I 
  wish 
  to 
  point 
  out 
  that 
  the 
  term 
  li 
  fog- 
  

   point 
  " 
  is 
  somewhat 
  of 
  a 
  misnomer 
  in 
  the 
  case 
  of 
  the 
  organic 
  

   liquids 
  enumerated 
  above. 
  I 
  found 
  it 
  always 
  possible 
  to 
  

  

  * 
  Light 
  is 
  known 
  to 
  induce 
  chemical 
  change 
  in 
  carbon 
  disulphide. 
  It 
  

   is 
  just 
  possible 
  that 
  this 
  chemical 
  change 
  may 
  be 
  preceded 
  by 
  electrical 
  

   disturbances 
  in 
  the 
  molecule., 
  giving 
  rise 
  to 
  ions 
  or 
  free 
  electrons. 
  

  

  