﻿Skey. 
  — 
  On 
  the 
  Movements 
  of 
  Camphor 
  on 
  Water. 
  477 
  

  

  camphor 
  are 
  the 
  effect 
  of 
  electrical 
  reactions, 
  but 
  that 
  this 
  is 
  not 
  so 
  appears 
  

   from 
  the 
  fact 
  that 
  neither 
  of 
  the 
  poles 
  of 
  a 
  six-pair 
  Grove 
  battery, 
  in 
  full 
  

   action 
  and 
  in 
  good 
  working 
  order, 
  at 
  all 
  effects 
  these 
  movements 
  when 
  

   applied 
  close 
  to 
  the 
  camphor. 
  The 
  poles 
  were 
  pointed 
  in 
  order 
  to 
  be 
  in 
  the 
  

   most 
  favourable 
  condition 
  for 
  effect. 
  

  

  The 
  ground 
  being 
  thus 
  cleared, 
  it 
  remains 
  for 
  me 
  to 
  tender 
  for 
  your 
  

   approval 
  a 
  theory 
  which, 
  in 
  my 
  opinion, 
  explains 
  the 
  phenomena 
  in 
  

   question. 
  This 
  I 
  will 
  do, 
  and 
  along 
  with 
  it 
  I 
  will 
  describe 
  or 
  demonstrate, 
  

   as 
  the 
  case 
  admits, 
  the 
  experimental 
  results 
  upon 
  which, 
  in 
  conjunction 
  

   with 
  those 
  related 
  above, 
  this 
  theory 
  is 
  based. 
  

  

  You 
  wiU 
  perhaps 
  remember 
  that 
  in 
  the 
  introductory 
  part 
  of 
  this 
  paper 
  

   Is 
  tated 
  to 
  you 
  the 
  well-known 
  fact 
  that, 
  for 
  the 
  exhibition 
  of 
  the 
  movements, 
  

   which 
  I 
  now 
  desire 
  to 
  explain, 
  it 
  is 
  necessary 
  to 
  have 
  the 
  water-surface 
  free 
  

   from 
  oily 
  matters. 
  Now 
  a 
  knowledge 
  of 
  this 
  is 
  highly 
  suggestive 
  ; 
  it 
  is 
  as 
  

   you 
  will 
  find 
  the 
  key 
  to 
  the 
  question 
  before 
  us. 
  A 
  drop 
  of 
  oil 
  (as 
  you 
  

   observe) 
  stops 
  in 
  a 
  peremptory 
  manner 
  all 
  camphor 
  movements, 
  and 
  it 
  

   is 
  now 
  our 
  proper 
  course 
  to 
  enquire 
  how 
  it 
  effects 
  this. 
  It 
  can 
  only, 
  so 
  

   far 
  as 
  I 
  see, 
  effect 
  this 
  in 
  two 
  ways, 
  either 
  by 
  enfilmning 
  the 
  camphor 
  

   and 
  so 
  preventing 
  evaporation, 
  or 
  it 
  is 
  not 
  as 
  a 
  suspensive 
  medium 
  favour- 
  

   able 
  to 
  the 
  continuance 
  of 
  such 
  movements 
  ; 
  thai 
  this 
  last 
  is 
  the 
  case 
  is 
  

   shown 
  by 
  the 
  following 
  experiment. 
  

  

  I 
  float 
  a 
  small 
  piece 
  of 
  cork 
  upon 
  turpentine, 
  on 
  this 
  cork 
  I 
  place 
  

   camphor, 
  and 
  you 
  observe 
  that 
  we 
  get 
  no 
  camphoric 
  movement.* 
  Clearly 
  

   then 
  it 
  appears 
  that 
  whether 
  we 
  are 
  to 
  get 
  the 
  phenomena 
  or 
  not 
  

   depends 
  upon 
  the 
  nature 
  of 
  the 
  surface 
  of 
  the 
  liquid 
  which 
  we 
  use 
  for 
  

   flotation, 
  and 
  this 
  independent 
  of 
  any 
  effect 
  it 
  may 
  have 
  upon 
  the 
  solid 
  

   camphor 
  in 
  preventing 
  its 
  evaporation. 
  The 
  knowledge 
  of 
  the 
  fact 
  that 
  

   oils 
  generally 
  are, 
  in 
  this 
  particular 
  respect, 
  antagonistic 
  to 
  camphor- 
  

   movements 
  I 
  sought 
  to 
  amplify, 
  and 
  in 
  this 
  I 
  have 
  succeeded. 
  Thus 
  I 
  

   find 
  that 
  besides 
  them 
  alcohol, 
  ether, 
  bi-sulphide 
  of 
  carbon 
  and 
  ammonia, 
  

   applied 
  even 
  as 
  vapours, 
  and 
  only 
  in 
  minute 
  quantities, 
  arrest 
  camphoric 
  

   movements 
  very 
  quickly. 
  I 
  further 
  find 
  that 
  such 
  movements 
  are 
  very 
  

   much 
  less 
  rapid 
  and 
  prolonged 
  if 
  the 
  water 
  used 
  is 
  charged 
  heavily 
  with 
  

   either 
  acids 
  or 
  salts. 
  f 
  

  

  Being 
  thus 
  acquainted 
  with 
  the 
  fact 
  that 
  so 
  many 
  and 
  such 
  diverse 
  sub- 
  

   stances 
  as 
  those 
  just 
  above 
  cited, 
  render 
  water 
  unfavourable 
  for 
  camphoric 
  

  

  * 
  This 
  fact, 
  by 
  the 
  way, 
  is 
  corroborative 
  of 
  the 
  correctness 
  of 
  the 
  opinion 
  I 
  have 
  

   ventiired 
  above, 
  viz., 
  that 
  camphor 
  movements 
  are 
  not 
  caused 
  directly 
  by 
  the 
  impinge- 
  

   ment 
  of 
  its 
  vapour 
  upon 
  the 
  liquid 
  which 
  floats 
  it. 
  

  

  t 
  I 
  have 
  since 
  found 
  that, 
  in 
  singular 
  opposition 
  to 
  these 
  vapours, 
  etc., 
  gasoline 
  not 
  

   only 
  refuses 
  to 
  stop 
  or 
  retard 
  camphoric 
  movements, 
  but 
  even 
  starts 
  them 
  in 
  case 
  of 
  

   camphor 
  rendered 
  stationary 
  in 
  this 
  way. 
  

   t 
  

  

  