﻿IS 
  THE 
  EARTH 
  GROWING 
  OLD? 
  POMPECKJ 
  263 
  

  

  The 
  answer 
  seemed 
  simple 
  in 
  the 
  period 
  of 
  the 
  unlimited 
  sway 
  of 
  

   the 
  laws 
  of 
  Kant 
  and 
  Laplace. 
  The 
  loss 
  of 
  heat 
  by 
  the 
  earth 
  entailed 
  

   a 
  shrinkinf^ 
  of 
  its 
  body; 
  this 
  led 
  through 
  the 
  crumpling 
  movements 
  

   in 
  the 
  relatively 
  solid 
  shell 
  to 
  a 
  distinction 
  between 
  high 
  and 
  low, 
  

   between 
  mountains 
  and 
  lowlands. 
  Herein 
  lay 
  the 
  cause 
  of 
  all 
  the 
  

   complexity 
  of 
  tlie 
  movements 
  to 
  which 
  the 
  earth's 
  crust 
  bears 
  wit- 
  

   ness. 
  

  

  An 
  especially 
  fortunate 
  form 
  of 
  reply 
  at 
  one 
  time 
  seemed 
  to 
  have 
  

   been 
  given, 
  an 
  enlightening 
  explanation 
  of 
  the 
  origin 
  of 
  the 
  high 
  

   and 
  low 
  places 
  on 
  the 
  earth 
  from 
  which 
  would 
  follow 
  necessarily 
  all 
  

   those 
  movements 
  which 
  we 
  are 
  considering 
  as 
  the 
  life 
  of 
  the 
  earth. 
  

   This 
  reply 
  came 
  from 
  Lowthian 
  Green 
  in 
  his 
  happy 
  thought 
  of 
  the 
  

   tetrahedral 
  remodeling 
  of 
  the 
  spheroidal 
  earth. 
  The 
  corners 
  and 
  

   the 
  edges 
  of 
  this 
  tetrahedral 
  earth 
  were, 
  as 
  this 
  illuminating 
  theory 
  

   explained, 
  the 
  necessary 
  high 
  regions 
  which 
  caused, 
  directed, 
  and 
  

   influenced 
  tlie 
  movements 
  upon 
  and 
  within 
  the 
  earth's 
  crust. 
  But 
  

   unfortunately 
  all 
  too 
  numerous 
  and 
  weighty 
  objections 
  can 
  be 
  

   brought 
  against 
  a 
  theory 
  based 
  upon 
  a 
  loss 
  of 
  heat 
  and 
  the 
  conse- 
  

   quent 
  contraction, 
  as 
  well 
  as 
  against 
  one 
  consequent 
  to 
  the 
  laws 
  of 
  

   the 
  nebular 
  hypothesis 
  relating 
  to 
  the 
  contraction 
  of 
  the 
  earth's 
  

   crust, 
  es]3ecially 
  as 
  connected 
  with 
  the 
  reactions 
  of 
  a 
  hot 
  

   interior 
  upon 
  the 
  outer 
  crust. 
  Such 
  theories 
  can 
  not 
  be 
  brought 
  

   into 
  general 
  recognition. 
  Just 
  as 
  there 
  are 
  great 
  objections 
  to 
  the 
  

   nebular 
  hypothesis 
  in 
  elucidating 
  the 
  relations 
  within 
  the 
  plane- 
  

   tary 
  system, 
  so 
  there 
  are 
  to 
  it 
  for 
  the 
  explanation 
  of 
  the 
  movements 
  

   which 
  constitute 
  the 
  earth's 
  life 
  history. 
  

  

  In 
  our 
  need 
  for 
  an 
  explanation 
  of 
  these 
  events 
  in 
  the 
  develop- 
  

   ments 
  observed 
  in 
  the 
  earth's 
  crust 
  we 
  readily, 
  perhaps 
  too 
  readily, 
  

   resort 
  to 
  the 
  phenomena 
  of 
  radioactivity. 
  Out 
  of 
  the 
  energy 
  released 
  

   from 
  the 
  radioactive 
  processes 
  we 
  could 
  conceive 
  a 
  simple 
  explana- 
  

   tion 
  of 
  the 
  phenomena 
  of 
  the 
  earth's 
  life. 
  Are 
  we 
  right 
  in 
  this? 
  

  

  However, 
  it 
  seems 
  that 
  at 
  present 
  w^e 
  must 
  rest 
  content 
  with 
  our 
  

   knowledge 
  of 
  these 
  phenomena 
  of 
  the 
  earth's 
  life, 
  their 
  interrela- 
  

   tionships, 
  alternations, 
  and 
  sequences. 
  

  

  And 
  now 
  let 
  us 
  get 
  back 
  to 
  to-day's 
  question 
  : 
  Is 
  the 
  earth 
  growing 
  

   old? 
  

  

  Out 
  of 
  the 
  400 
  to 
  1,600 
  million 
  years 
  of 
  the 
  earth's 
  history 
  of 
  which 
  

   we 
  know 
  something, 
  can 
  we 
  detect 
  such 
  changes 
  in 
  the 
  evidence 
  of 
  

   the 
  earth's 
  life 
  as 
  would 
  lead 
  us 
  to 
  the 
  conclusion 
  that 
  there 
  is 
  a 
  

   crippling 
  in 
  these 
  activities 
  ? 
  Such 
  a 
  crippling 
  would 
  mean 
  " 
  grow- 
  

   ing 
  old." 
  

  

  So 
  far 
  as 
  the 
  rock 
  records 
  of 
  the 
  earth 
  are 
  legible, 
  the 
  "actuality" 
  

   principle, 
  enunciated 
  by 
  Hutton 
  and 
  more 
  fimdamentally 
  stated 
  by 
  

   Hoff 
  and 
  Lyell, 
  holds 
  for 
  the 
  processes 
  within 
  the 
  earth's 
  crust 
  

  

  