﻿Dr. 
  van 
  Rijckevorsel 
  on 
  the 
  Temperature 
  of 
  Europe. 
  4:59 
  

  

  sulphuric 
  acid 
  is 
  due 
  to 
  small 
  particles 
  of 
  the 
  dissolved 
  sub- 
  

   stance 
  left 
  when 
  the 
  cloud 
  evaporates 
  over 
  the 
  acid. 
  Town- 
  

   send's 
  experiments 
  confirm 
  this 
  view, 
  for 
  he 
  finds 
  that 
  the 
  

   particles 
  left 
  when 
  the 
  cloud 
  is 
  evaporated 
  are 
  large 
  compared 
  

   with 
  molecular 
  dimensions. 
  

  

  In 
  the 
  case 
  of 
  a 
  gas 
  coming 
  off' 
  from 
  more 
  or 
  less 
  dilute 
  

   sulphuric 
  acid 
  it 
  seems 
  reasonable 
  to 
  suppose 
  that 
  the 
  nuclei 
  

   which 
  cause 
  the 
  formation 
  of 
  the 
  clouds 
  consist 
  of 
  this 
  sub- 
  

   stance, 
  but 
  exactly 
  how 
  the 
  gas 
  becomes 
  charged 
  with 
  such 
  

   an 
  immense 
  number 
  of 
  these 
  particles 
  as 
  is 
  necessary 
  to 
  form 
  

   a 
  dense 
  cloud 
  is 
  not 
  known. 
  

  

  The 
  most 
  obvious 
  explanation, 
  viz. 
  that 
  the 
  particles 
  are 
  

   simply 
  spray 
  splashed 
  off, 
  does 
  not 
  seem 
  able 
  to 
  account 
  for 
  

   many 
  of 
  the 
  facts 
  observed 
  by 
  Townsend. 
  I 
  am 
  not, 
  however, 
  

   here 
  concerned 
  with 
  the 
  origin 
  of 
  these 
  particles 
  in 
  newly 
  

   prepared 
  gases, 
  and 
  shall 
  not, 
  therefore, 
  consider 
  the 
  question 
  

   any 
  further. 
  The 
  chief 
  results 
  obtained 
  in 
  these 
  experiments 
  

   are 
  : 
  

  

  (1) 
  A 
  cloud 
  of 
  pure 
  water 
  when 
  evaporated 
  by 
  bubbling 
  

   through 
  H 
  2 
  S0 
  4 
  does 
  not 
  reappear 
  over 
  water. 
  

  

  (2) 
  A 
  cloud 
  of 
  a 
  dilute 
  solution 
  of 
  a 
  nonvolatile 
  substance 
  

   when 
  evaporated 
  reappears 
  over 
  water. 
  

  

  (3) 
  Electrification 
  of 
  the 
  original 
  cloud 
  in 
  either 
  of 
  the 
  

   above 
  cases 
  does 
  not 
  affect 
  the 
  reappearance 
  of 
  it 
  over 
  water 
  

   after 
  evaporation, 
  although 
  the 
  electrification 
  is 
  not 
  stopped 
  

   by 
  the 
  acid. 
  

  

  In 
  conclusion, 
  I 
  desire 
  to 
  say 
  that 
  my 
  best 
  thanks 
  are 
  due 
  

   to 
  Prof. 
  Thomson 
  for 
  much 
  information 
  and 
  advice 
  during 
  

   the 
  course 
  of 
  these 
  experiments. 
  

  

  XLVI1. 
  On 
  the 
  Temperature 
  of 
  Europe. 
  

   By 
  Dr. 
  van 
  Rijckevorsel 
  *. 
  

  

  WHAT 
  I 
  am 
  going 
  to 
  put 
  before 
  you 
  is 
  not 
  absolutely 
  

   new. 
  Indeed, 
  I 
  believe 
  that 
  most 
  meteorologists 
  

   have 
  felt 
  that 
  something 
  like 
  it 
  must 
  be 
  the 
  case; 
  and 
  many 
  

   have 
  said 
  something 
  amounting 
  to 
  the 
  expression 
  of 
  such 
  a 
  

   feeling 
  in 
  some 
  of 
  their 
  works. 
  Certainly 
  Roche, 
  Jelinek, 
  

   Buys-Ballot 
  are 
  among 
  the 
  number, 
  not 
  to 
  speak 
  of 
  others. 
  

  

  But 
  nobody, 
  as 
  far 
  as 
  I 
  know, 
  has 
  followed 
  to 
  the 
  end 
  the 
  

   path 
  of 
  which 
  many 
  seem 
  to 
  have 
  seen 
  the 
  entrance 
  ; 
  and 
  so 
  

   nobody 
  has 
  as 
  yet 
  perceived 
  how 
  it 
  seems 
  to 
  be 
  a 
  new 
  road 
  to 
  

   some 
  knowledge 
  about 
  temperature 
  and 
  climate. 
  

  

  What 
  I 
  have 
  done 
  is 
  very 
  simple. 
  I 
  have 
  collected 
  and 
  

  

  * 
  Communicated 
  by 
  Prof. 
  G. 
  F. 
  FitzGerald, 
  F.R.S., 
  having 
  been 
  read 
  

   before 
  Section 
  A 
  of 
  the 
  British 
  Association 
  at 
  Toronto. 
  

  

  