﻿( 
  THE 
  

   LONDON, 
  EDINBURGH, 
  and 
  DUBLIN 
  

  

  PHILOSOPHICAL 
  MAGAZINE 
  

  

  AND 
  

  

  JOURNAL 
  OF 
  SCIENCE. 
  

  

  [SIXTH 
  SERIES.] 
  

  

  : 
  

  

  JANUARY 
  1918. 
  Jfi 
  

  

  

  

  I. 
  Notes 
  on 
  the 
  Theory 
  of 
  Lubrication. 
  

   By 
  Lord 
  Rayleigh, 
  O.M., 
  F.R.S* 
  

  

  MODERN 
  views 
  respecting 
  mechanical 
  lubrication 
  are 
  

   founded 
  mainly 
  on 
  the 
  experiments 
  of 
  B. 
  Tower 
  f, 
  

   conducted 
  upon 
  journal 
  bearings. 
  He 
  insisted 
  upon 
  the 
  

   importance 
  of 
  a 
  complete 
  film 
  of 
  oil 
  between 
  the 
  opposed 
  

   solid 
  surfaces, 
  and 
  he 
  showed 
  how 
  in 
  this 
  case 
  the 
  main- 
  

   tenance 
  of 
  the 
  film 
  may 
  be 
  attained 
  by 
  the 
  dragging 
  action 
  of 
  

   the 
  surfaces 
  themselves, 
  playing 
  the 
  part 
  of 
  a 
  pump. 
  To 
  

   this 
  end 
  it 
  is 
  •" 
  necessary 
  that 
  the 
  layer 
  should 
  be 
  thicker,.oii_ 
  

   the 
  ingoing 
  than 
  on 
  the 
  outgoing 
  side 
  "J, 
  which 
  involves 
  a 
  

   slight 
  "cTTsplacement 
  of 
  the 
  centre 
  of 
  the 
  journal 
  from 
  that 
  of 
  

   the 
  bearing. 
  The 
  theory 
  w 
  T 
  as 
  afterwards 
  developed 
  by 
  

   0. 
  Reynolds, 
  whose 
  important 
  memoir 
  § 
  includes 
  most 
  of 
  

   what 
  is 
  now 
  known 
  upon 
  the 
  subject. 
  In 
  a 
  later 
  paper 
  

   Sommerfeld 
  has 
  improved 
  considerably 
  upon 
  the 
  mathe- 
  

   matics, 
  especially 
  in 
  the 
  case 
  where 
  the 
  bearing 
  completely 
  

   envelops 
  the 
  journal, 
  and 
  his 
  exposition 
  || 
  is 
  much 
  to 
  be 
  

   recommended 
  to 
  those 
  who 
  wish 
  to 
  follow 
  the 
  details 
  of 
  the 
  

   investigation. 
  Reference 
  may 
  also 
  be 
  made 
  to 
  Harrison 
  % 
  

   who 
  includes 
  the 
  consideration 
  of 
  compressible 
  lubricants 
  

   (air). 
  

  

  * 
  Communicated 
  by 
  the 
  Author. 
  

   t 
  Proc. 
  Inst. 
  Mech. 
  Eng. 
  1883, 
  1884. 
  

  

  X 
  British 
  Association 
  Address 
  at 
  Montreal, 
  1884; 
  Eayleig-h's 
  Scientific 
  

   Papers, 
  vol. 
  ii. 
  p. 
  344. 
  

  

  § 
  Phil. 
  Trans, 
  vol. 
  177. 
  p. 
  157 
  (1886). 
  

   |! 
  ZeiUchr.f. 
  Math. 
  t. 
  50. 
  p. 
  97 
  (1904). 
  

   f 
  Camb. 
  Trans, 
  vol. 
  xxii. 
  p. 
  39 
  (1913). 
  

  

  Phil. 
  Mag. 
  S. 
  6. 
  Vol. 
  35. 
  No. 
  205. 
  Jan. 
  1918. 
  B 
  

  

  / 
  

  

  