﻿delations 
  in 
  Capillaritij. 
  503 
  

  

  Integrating 
  by 
  parts 
  we 
  have 
  

  

  The 
  term 
  within 
  the 
  brackets 
  vanishes 
  at 
  both 
  Kmits 
  and 
  

  

  Therefore 
  the 
  work 
  required 
  is 
  

  

  The 
  expenditure 
  of 
  this 
  amount 
  of 
  work 
  has 
  resulted 
  in 
  the 
  

   production 
  of 
  two 
  surfaces 
  each 
  of 
  unit 
  area. 
  Hence 
  the 
  

   V 
  work 
  expended 
  per 
  unit 
  area 
  (i. 
  e. 
  the 
  surface-tension) 
  is 
  

  

  Comparing 
  this 
  with 
  equations 
  (4) 
  and 
  (8) 
  we 
  see 
  that 
  

  

  The 
  latter 
  expression 
  may 
  be 
  conveniently 
  divided 
  into 
  two 
  

  

  , 
  .' 
  and 
  ^ 
  ~. 
  

  

  oc^lt 
  m 
  

  

  The 
  first 
  part 
  depends 
  only 
  upon 
  the 
  temperature, 
  and 
  is 
  the 
  

   same 
  for 
  different 
  liquids 
  at 
  corresponding 
  temperatures. 
  

   The 
  latter 
  part 
  involves 
  only 
  quantities 
  which 
  are 
  funda- 
  

   mental 
  and 
  do 
  not 
  depend 
  upon 
  temperature 
  or 
  anything 
  else 
  

   except 
  the 
  nature 
  of 
  the 
  atom. 
  The 
  first 
  part 
  therefore 
  

   expresses 
  the 
  effect 
  of 
  the 
  change 
  in 
  the 
  geometrical 
  con- 
  

   figuration 
  of 
  the 
  molecules 
  accompanying 
  rise 
  of 
  temperature 
  

   on 
  the 
  surface-tension 
  of 
  the 
  liquid. 
  

  

  Since 
  the 
  function 
  k 
  is 
  approximately 
  proportional 
  to 
  the 
  

   absolute 
  temperature 
  it 
  may 
  be 
  put 
  equal 
  to 
  W/3 
  where 
  W 
  

   is 
  an 
  appropriate 
  constant. 
  Hence 
  

  

  E=^(Eo.)^ 
  (9) 
  

  

  Whittaker 
  has 
  obtained 
  a 
  relation 
  between 
  the 
  potential 
  

   energy, 
  the 
  internal 
  latent 
  heat 
  of 
  evaporation, 
  and 
  the 
  

   absolute 
  temperature. 
  He 
  shows 
  that 
  

  

  LKT 
  = 
  E, 
  

   where 
  K 
  is 
  a 
  constant 
  which 
  is 
  different 
  for 
  different 
  liquids. 
  

  

  