﻿68 
  THE 
  REALM 
  OF 
  ORGANISMS 
  CONTRASTED 
  

  

  atom 
  is 
  not 
  the 
  natural 
  limit 
  of 
  the 
  subdivision 
  of 
  matter, 
  

   that 
  the 
  stream 
  of 
  energy 
  poured 
  forth 
  by 
  radium 
  is 
  due 
  to 
  

   a 
  transmutation 
  of 
  the 
  position 
  of 
  parts 
  constituting 
  the 
  

   atom, 
  the 
  radium 
  slowly 
  changing 
  into 
  something 
  else 
  

   helium, 
  and 
  eventually 
  lead. 
  

  

  The 
  individual 
  molecules 
  of 
  matter 
  in 
  a 
  gaseous 
  state 
  

   are 
  believed 
  to 
  move 
  with 
  great 
  velocity, 
  incessantly 
  collid- 
  

   ing 
  with 
  one 
  another 
  and 
  rebounding, 
  making 
  impacts 
  on 
  

   the 
  walls 
  of 
  the 
  vessel 
  that 
  contains 
  them, 
  or 
  spreading 
  

   themselves 
  through 
  any 
  space 
  to 
  which 
  there 
  is 
  free 
  access. 
  

   . 
  . 
  . 
  We 
  need 
  not 
  try 
  to 
  follow 
  what 
  is 
  beyond 
  our 
  per- 
  

   sonal 
  scope, 
  but 
  to 
  illustrate 
  the 
  subtlety 
  of 
  modern 
  con- 
  

   ceptions 
  of 
  matter 
  which 
  is 
  all 
  that 
  concerns 
  us 
  at 
  pres- 
  

   ent 
  let 
  us 
  take 
  a 
  few 
  sentences 
  from 
  Professor 
  Soddy's 
  

   luminous 
  Matter 
  and 
  Energy: 
  

  

  " 
  Every 
  cubic 
  centimetre 
  of 
  any 
  gas, 
  measured 
  under 
  

   standard 
  conditions 
  (0 
  C. 
  and 
  760 
  millimetres 
  baromet- 
  

   ric 
  pressure), 
  contains 
  twenty-seven 
  million 
  million 
  mil- 
  

   lion 
  molecules. 
  The 
  weight 
  of 
  the 
  single 
  molecule 
  of 
  hydro- 
  

   gen 
  is 
  about 
  three 
  million-million-million-millionths 
  of 
  a 
  

   gram, 
  and 
  its 
  velocity 
  at 
  C. 
  is 
  rather 
  more 
  than 
  a 
  mile 
  

   a 
  second. 
  The 
  hydrogen 
  molecule 
  is, 
  it 
  is 
  true, 
  the 
  smallest 
  

   and 
  simplest 
  molecule 
  of 
  matter 
  known, 
  but 
  it 
  is 
  a 
  large 
  and 
  

   sluggishly 
  moving 
  individual 
  compared 
  with 
  another 
  known 
  

   particle, 
  the 
  electron 
  or 
  atom 
  of 
  negative 
  electricity 
  ' 
  

   (Matter 
  and 
  Energy, 
  p. 
  82). 
  

  

  When 
  the 
  temperature 
  of 
  a 
  gas 
  is 
  lowered 
  the 
  molecules 
  

   come 
  nearer 
  one 
  another, 
  till 
  their 
  mutual 
  tendency 
  to 
  draw 
  

   together 
  restricts 
  their 
  wandering 
  movements, 
  and 
  a 
  liquid 
  

   is 
  formed. 
  Inside 
  the 
  surface 
  skin 
  of 
  the 
  liquid 
  the 
  molecules 
  

   move 
  very 
  rapidly, 
  and 
  collide 
  so 
  frequently 
  that 
  they 
  fol- 
  

   low 
  very 
  zigzag 
  paths, 
  being 
  perpetually 
  turned 
  back 
  the 
  

  

  