﻿184 
  Transactions. 
  — 
  Chemistnj, 
  

  

  before, 
  as 
  I 
  tldnh 
  (tliis 
  is, 
  liowever, 
  for 
  measurement), 
  and 
  such 
  

   surface 
  will 
  not 
  allow 
  kerosene 
  or 
  turpentine 
  to 
  flow 
  over 
  it; 
  i.e., 
  a 
  

   drop 
  of 
  either 
  put 
  on 
  keeps 
  in 
  nearly 
  the 
  drop 
  form 
  ; 
  in 
  pure 
  

   water 
  they 
  would 
  flow 
  over 
  instantaneously. 
  I 
  have 
  got 
  the 
  

   surface 
  to 
  refuse 
  olive 
  oil 
  even, 
  a 
  very 
  searching 
  oil 
  though 
  a 
  

   slow 
  mover. 
  This 
  shows 
  that 
  such 
  surface 
  is 
  a 
  combination 
  

   of 
  camphor 
  with 
  water 
  ; 
  and 
  I 
  am 
  now 
  enabled 
  to 
  fill 
  up 
  a 
  

   break 
  you 
  would 
  observe 
  in 
  the 
  continuity 
  of 
  my 
  paper. 
  I 
  

   now 
  show 
  how 
  camphor 
  forms 
  some 
  compound 
  with 
  water, 
  

   which 
  will 
  not 
  allow 
  oil 
  to 
  flow 
  over 
  it. 
  This 
  compound 
  

   is 
  not 
  camphor, 
  because 
  camphor 
  is 
  soluble 
  in 
  oil. 
  I 
  think 
  it 
  

   is 
  probably 
  the 
  hydrate. 
  If 
  it 
  is 
  the 
  hydrate, 
  the 
  surface 
  should, 
  

   by 
  continued 
  exposure, 
  again 
  rotate 
  camphor, 
  or 
  allow 
  oil 
  to 
  flow 
  

   over 
  it 
  ; 
  and 
  I 
  find 
  that 
  two 
  hours' 
  exposure 
  of 
  a 
  non-rotating 
  

   surface 
  does 
  restore 
  to 
  it 
  the 
  property 
  of 
  rotation. 
  

   II. 
  That 
  vapour 
  does 
  not 
  necessarily 
  repel, 
  seems 
  shown 
  by 
  the 
  fact 
  

   that 
  cork, 
  on 
  turpentine, 
  or 
  kerosene, 
  is 
  attracted 
  by 
  ammonia 
  

   vapour. 
  Now, 
  ammonia 
  is 
  a 
  substance 
  which, 
  being 
  rapidly 
  

   evolved 
  — 
  far 
  more 
  so 
  than 
  camphor 
  — 
  should 
  repel 
  cork 
  on 
  tur- 
  

   pentine 
  strongly. 
  (Camphor, 
  I 
  may 
  say, 
  and 
  ether, 
  and 
  alcohol, 
  

   do 
  repel 
  cork 
  on 
  this 
  liquid). 
  

  

  Again 
  : 
  Turpentine 
  vapour 
  does 
  not 
  repel 
  cork 
  on 
  turpentine, 
  

   but 
  it 
  repels 
  cork 
  on 
  water 
  ; 
  and 
  water 
  offers 
  more 
  resistance 
  to 
  

   the 
  movements 
  of 
  substances 
  swimming 
  on 
  it 
  than 
  to 
  substances 
  

   swimming 
  on 
  turpentine. 
  

  

  Clearly 
  the 
  idea 
  that 
  vapour 
  in 
  transit 
  (molecular 
  movement) 
  

  

  can 
  move 
  masses 
  of 
  matter 
  visibly 
  to 
  us, 
  does 
  not 
  receive 
  any 
  

  

  support 
  from 
  such 
  results 
  as 
  these. 
  

  

  I 
  am 
  led 
  to 
  hold 
  by 
  researches 
  here, 
  and 
  by 
  thought 
  on 
  the 
  matter, 
  that 
  

  

  the 
  generally 
  received 
  idea 
  that 
  vapour 
  exercises 
  a 
  direct 
  repellent 
  force, 
  is 
  

  

  entirely 
  erroneous 
  ; 
  it 
  appears 
  to 
  do 
  so, 
  but 
  it 
  in 
  reality 
  forms 
  a 
  compound 
  

  

  with 
  the 
  liquid 
  it 
  appears 
  to 
  repel. 
  A 
  compound 
  being 
  lighter, 
  or 
  having 
  

  

  greater 
  diffusive 
  power 
  than 
  the 
  normal 
  liquid, 
  rolls 
  like 
  a 
  wave 
  away 
  from 
  

  

  the 
  supply, 
  and 
  carries 
  any 
  dust 
  mechanically 
  with 
  it, 
  giving 
  the 
  apparent 
  

  

  repulsive 
  effect 
  observed. 
  

  

  Kepulsion 
  by 
  direct 
  force 
  of 
  vapour 
  is, 
  I 
  hold, 
  an 
  optical 
  illusion, 
  and 
  

   one 
  which 
  physicists 
  should 
  long 
  since 
  have 
  exploded 
  by 
  force 
  of 
  pure 
  

   mathematical 
  formulte, 
  and 
  not 
  left 
  it 
  as 
  a 
  job 
  for 
  chemists. 
  

  

  I 
  shall 
  in 
  a 
  future 
  paper 
  take 
  the 
  larger 
  subject, 
  that 
  no 
  kind 
  of 
  matter 
  

   can 
  be 
  visibly 
  repelled 
  while 
  intercepting 
  vapour 
  in 
  transit 
  so 
  long 
  as 
  a 
  

   common 
  temperature 
  is 
  observed 
  and 
  the 
  pressure 
  is 
  not 
  notably 
  irregular, 
  

  

  