﻿8 
  Lord 
  Kelvin 
  on 
  Gravitational 
  Matter. 
  

  

  of 
  that 
  of 
  water. 
  If 
  now, 
  instead 
  of 
  an 
  ideal 
  compressible 
  

   fluid, 
  we 
  go 
  back 
  to 
  atoms 
  of 
  ordinary 
  matter 
  of 
  all 
  kinds 
  as 
  

   the 
  primitive 
  occupants 
  of 
  our 
  sphere 
  of 
  3'09.10 
  16 
  kilometres 
  

   radius, 
  all 
  these 
  conclusions, 
  provided 
  all 
  the 
  velocities 
  are 
  

   less 
  than 
  the 
  velocity 
  of 
  light, 
  would 
  still 
  hold, 
  notwith- 
  

   standing 
  the 
  ether 
  occupying 
  the 
  space 
  through 
  which 
  the 
  

   atoms 
  move. 
  This 
  would, 
  I 
  believe 
  *, 
  exercise 
  no 
  resistance 
  

   whatever 
  to 
  uniform 
  motion 
  of 
  an 
  atom 
  through 
  it 
  ; 
  but 
  it 
  

   would 
  certainly 
  add 
  quasi-inertia 
  to 
  the 
  intrinsic 
  Newtonian 
  

   inertia 
  of 
  the 
  atom 
  itself 
  moving 
  through 
  ideal 
  space 
  void 
  of 
  

   ether; 
  which, 
  according 
  to 
  the 
  Newtonian 
  law, 
  would 
  be 
  

   exactly 
  in 
  proportion 
  to 
  the 
  amount 
  of 
  its 
  gravitational 
  

   quality. 
  The 
  additional 
  quasi-inertia 
  must 
  be 
  exceedingly 
  

   small 
  in 
  comparison 
  with 
  the 
  Newtonian 
  inertia, 
  as 
  is 
  de- 
  

   monstrated 
  by 
  the 
  Newtonian 
  proofs, 
  including 
  that 
  founded 
  

   on 
  Kepler's 
  laws 
  for 
  the 
  groups 
  of 
  atoms 
  constituting 
  the 
  

   planets, 
  and 
  movable 
  bodies 
  experimented 
  on 
  at 
  the 
  earth's 
  

   surface. 
  

  

  In 
  one 
  thousand 
  seconds 
  of 
  time 
  after 
  the 
  density 
  *0161 
  of 
  

   the 
  density 
  of 
  water 
  is 
  reached, 
  the 
  inward 
  surface 
  velocity 
  

   would 
  be 
  305,000 
  kilometres 
  per 
  second, 
  or 
  greater 
  than 
  the 
  

   velocity 
  of 
  light 
  ; 
  and 
  the 
  whole 
  surface 
  of 
  our 
  condensing 
  

   globe 
  of 
  gas 
  or 
  vapour 
  or 
  crowd 
  of 
  atoms 
  would 
  begin 
  to 
  

   glow, 
  shedding 
  light 
  inwards 
  and 
  outwards. 
  All 
  this 
  is 
  

   absolutely 
  realistic, 
  except 
  the 
  assumption 
  of 
  uniform 
  dis- 
  

   tribution 
  through 
  a 
  sphere 
  of 
  the 
  enormous 
  radius 
  of 
  3*09. 
  10 
  16 
  

   kilometres, 
  which 
  we 
  adopted 
  temporarily 
  for 
  illustrational 
  

   purpose. 
  The 
  enormously 
  great 
  velocity 
  (291,000 
  kilo- 
  

   metres 
  per 
  second) 
  and 
  rate 
  of 
  acceleration 
  (13*7 
  kilometres 
  

   per 
  second 
  per 
  second) 
  of 
  the 
  boundary 
  inwards, 
  which 
  we 
  

   found 
  at 
  the 
  instant 
  of 
  density 
  '0161 
  of 
  that 
  of 
  water, 
  are 
  due 
  

   to 
  greatness 
  of 
  the 
  primitive 
  radius, 
  and 
  the 
  uniformity 
  of 
  

   density 
  in 
  the 
  primitive 
  distribution. 
  

  

  ~~ 
  To 
  come 
  to 
  reality, 
  according 
  to 
  the 
  most 
  probable 
  

   judgment 
  present 
  knowledge 
  allows 
  us 
  to 
  form, 
  suppose 
  at 
  

   many 
  millions, 
  or 
  thousands 
  of 
  millions, 
  or 
  millions 
  of 
  millions 
  

   o£ 
  years 
  ago, 
  all 
  the 
  matter 
  in 
  the 
  universe 
  to 
  have 
  been 
  atoms 
  

   very 
  nearly 
  at 
  rest 
  f 
  or 
  quite 
  at 
  rest 
  ; 
  more 
  densely 
  dis- 
  

  

  * 
  ' 
  On 
  the 
  Motion 
  produced 
  in 
  an 
  Infinite 
  Elastic 
  Solid 
  by 
  the 
  Motion 
  

   through 
  the 
  Space 
  occupied 
  by 
  it 
  of 
  a 
  Body 
  acting 
  on 
  it 
  only 
  by 
  

   Attraction 
  or 
  Repulsion/ 
  Cong. 
  International 
  de 
  Physique, 
  Paris, 
  

   Volume 
  of 
  Reports 
  ; 
  Phil. 
  Mag., 
  August 
  1900. 
  

  

  t 
  * 
  On 
  Mechanical 
  Antecedents 
  of 
  Motion, 
  Heat, 
  and 
  Light,' 
  Brit.. 
  

   Assoc. 
  Rep., 
  Part 
  2, 
  1854; 
  Edin. 
  New. 
  Phil. 
  Jour. 
  vol. 
  i. 
  1855 
  ; 
  Comptes 
  

   Rendus, 
  vol. 
  xl. 
  1855; 
  Kelvin's 
  Collected 
  Math, 
  and 
  Phys. 
  Papers 
  

   vol. 
  ii. 
  art. 
  lxix. 
  

  

  