﻿Theory 
  of 
  Gravity. 
  663 
  

  

  components 
  : 
  — 
  

  

  - 
  — 
  (E^ 
  + 
  I^HJ-u^^-XE^-E^). 
  

   The 
  surface 
  conditions 
  are 
  

  

  And 
  by 
  using- 
  these 
  it 
  can 
  be 
  shown 
  that 
  the 
  flux 
  of 
  

   momentum 
  is 
  normal 
  and 
  equal 
  to 
  

  

  and 
  also 
  that 
  the 
  flux 
  of 
  energy 
  is 
  

  

  The 
  flux 
  of 
  gravitational 
  momentum 
  has 
  the 
  components 
  

   1 
  (dJ\ 
  2 
  , 
  1 
  fdJ\* 
  , 
  ,. 
  N 
  ,djdj 
  

  

  1 
  tfJUJ 
  „ 
  - 
  .rfJAT" 
  

   47r 
  a# 
  dy 
  a?/ 
  ca£ 
  

  

  1 
  dJdJ 
  ,. 
  s 
  _,dJdJ 
  

   4^cUcU 
  +U 
  « 
  (im] 
  ] 
  Tznti' 
  

  

  Across 
  the 
  bounding 
  surface 
  of 
  matter 
  J 
  the 
  gravitational 
  

   potential 
  and 
  its 
  first 
  differential 
  coefficients 
  are 
  continuous. 
  

   But 
  the 
  gravitational 
  energy 
  containing 
  the 
  term 
  —mj 
  

   changes 
  abruptly. 
  

  

  The 
  total 
  flux 
  of 
  momentum 
  across 
  the 
  surface 
  into 
  gether 
  

   is 
  therefore 
  greater 
  than 
  the 
  flux 
  out 
  of 
  matter 
  by 
  the 
  normal 
  

   component 
  

  

  This 
  is 
  by 
  (69) 
  equal 
  to 
  

  

  V 
  — 
  V 
  

   and 
  the 
  fluxes 
  of 
  energy 
  will 
  be 
  found 
  to 
  differ 
  by 
  

  

  {V 
  a 
  -V 
  m 
  )u 
  n 
  . 
  

  

  2 
  Y 
  2 
  

  

  