﻿IS 
  THE 
  EARTH 
  GROWING 
  OLD? 
  POMPECKJ 
  259 
  

  

  of 
  the 
  same 
  order 
  of 
  magnitude, 
  and 
  large. 
  For 
  the 
  duration 
  

   of 
  the 
  diluvium 
  about 
  1.5 
  million 
  years 
  was 
  computed. 
  Uranium 
  

   minerals 
  from 
  the 
  Carboniferous 
  age 
  indicate 
  a 
  lapse 
  of 
  335 
  million 
  

   years 
  and 
  rocks 
  from 
  the 
  pre-Cambrian, 
  the 
  period 
  wherein 
  there 
  is 
  

   direct 
  evidence 
  of 
  a 
  rich 
  and 
  already 
  much 
  differentiated 
  organic 
  life, 
  

   a 
  lapse 
  of 
  1,000 
  to 
  1,G00 
  million 
  years.^ 
  * 
  

  

  The 
  values 
  obtained 
  in 
  this 
  manner 
  exceed 
  from 
  fourfold 
  to 
  much 
  

   more 
  those 
  obtained 
  from 
  other 
  geological 
  methods. 
  They 
  are, 
  

   indeed, 
  very 
  much 
  greater 
  than 
  most 
  estimates 
  based 
  upon 
  the 
  Kant- 
  

   Laplace 
  hypothesis 
  as 
  connected 
  with 
  the 
  cooling 
  of 
  the 
  earth 
  from 
  

   a 
  molten 
  condition 
  to 
  its 
  present 
  temperature. 
  Whether 
  it 
  is 
  possible 
  

   that 
  a 
  more 
  thorough 
  knowledge 
  of 
  the 
  course 
  and 
  duration 
  of 
  the 
  

   radioactive 
  processes 
  may 
  reduce 
  the 
  age 
  values 
  deduced 
  from 
  such 
  

   processes 
  — 
  and 
  Joly 
  has 
  already 
  raised 
  objections 
  against 
  the 
  very 
  

   high 
  values 
  won 
  through 
  the 
  uranium-lead 
  reactions 
  — 
  or 
  tlie 
  values 
  

   obtained 
  from 
  geological 
  evidence 
  come 
  nearer 
  the 
  truth, 
  one 
  thing 
  

   remains 
  certain: 
  The 
  scanty 
  section 
  of 
  the 
  earth's 
  body, 
  which 
  we 
  

   know 
  geologically, 
  is 
  old. 
  Gradually 
  we 
  have 
  regained 
  our 
  lost 
  

   respect 
  for 
  great 
  values. 
  Even 
  the 
  approximately 
  300,000,000 
  to 
  

   400,000,000 
  years, 
  which 
  is 
  indicated 
  by 
  the 
  salt 
  method 
  applied 
  to 
  

   the 
  sedimentation 
  within 
  the 
  earth's 
  surface 
  layers, 
  suffice 
  for 
  the 
  

   indication 
  of 
  a 
  very 
  high 
  figure 
  for 
  the 
  age 
  of 
  these 
  layers 
  known. 
  

   However, 
  we 
  must 
  assert 
  very 
  strongly 
  that 
  we 
  are 
  far 
  from 
  able 
  

   by 
  geological 
  means 
  to 
  set 
  the 
  time 
  of 
  the 
  beginning 
  of 
  the 
  formation 
  

   of 
  the 
  crust 
  of 
  this 
  earth. 
  Evidently 
  the 
  complete 
  time 
  for 
  the 
  exist- 
  

   ence 
  of 
  the 
  earth 
  must 
  be 
  very 
  manyfolcl 
  that 
  of 
  the 
  geologically 
  

   determined 
  period 
  of 
  the 
  earth's 
  history." 
  

  

  Is 
  this 
  earth, 
  whose 
  age 
  is 
  so 
  many 
  millions 
  of 
  years, 
  as 
  thus 
  read 
  

   from 
  the 
  rocks 
  within 
  its 
  crust, 
  really 
  growing 
  senile 
  ? 
  

  

  And 
  this 
  riddle 
  is 
  well 
  asked. 
  We 
  speak 
  of 
  the 
  stars 
  as 
  growing 
  

   old 
  along 
  the 
  sequence 
  from 
  the 
  white 
  stars 
  to 
  the 
  yellow, 
  from 
  the 
  

   yellow 
  to 
  the 
  red; 
  the 
  moon 
  is 
  believed 
  to 
  have 
  rapidly 
  aged 
  and 
  

   died; 
  the 
  cosmos 
  presses 
  on 
  to 
  a 
  warm 
  death; 
  life 
  on 
  this 
  globe 
  

   presses 
  on 
  to 
  a 
  cold 
  death. 
  

  

  ^ 
  How 
  widely 
  the 
  estimates 
  of 
  ages 
  from 
  the 
  uranium 
  and 
  thorium 
  minerals 
  may 
  vary 
  

   is 
  indicated 
  by 
  the 
  work 
  of 
  L. 
  A. 
  Collins 
  (Amer. 
  Jour. 
  Sci., 
  5th 
  series, 
  vol. 
  12, 
  July, 
  

   1920). 
  .The 
  following 
  ages 
  for 
  pre-Cambrian 
  minerals 
  of 
  Australia 
  were 
  estimated: 
  For 
  

   a 
  fergusonite, 
  620; 
  a 
  mackiutoshito, 
  1,475; 
  a 
  pilbarite, 
  about 
  3,840 
  million 
  years. 
  How- 
  

   ever, 
  the 
  last-named 
  mineral 
  is 
  annotated 
  as 
  " 
  altered," 
  so 
  that 
  within 
  it 
  the 
  lead-uranium 
  

   relationship 
  should 
  not 
  be 
  normal 
  but 
  the 
  range 
  from 
  620 
  up 
  to 
  1,475 
  million 
  years 
  does 
  

   not 
  seem 
  very 
  small. 
  

  

  ^^ 
  The 
  late 
  Professor 
  Barrell 
  (Bull. 
  Geol. 
  Soc. 
  of 
  Amer., 
  vol. 
  28, 
  1917) 
  estimated 
  the 
  

   time 
  since 
  the 
  beginning 
  of 
  the 
  Cambrian 
  period 
  at 
  700,000,000 
  years, 
  basing 
  his 
  con- 
  

   clusions 
  mainly 
  on 
  radioactive 
  data. 
  (Translator's 
  note.) 
  

  

  * 
  Nernst, 
  arguing 
  generally 
  from 
  the 
  Kant-I..aplace 
  theory, 
  estimates 
  the 
  period 
  of 
  the 
  

   earth's 
  existence 
  as 
  a 
  hot 
  liquid 
  ball 
  as 
  equivalent 
  to 
  the 
  length 
  of 
  time 
  which 
  has 
  elapsed 
  

   since 
  the 
  formation 
  of 
  the 
  earth's 
  crust, 
  as 
  obtained 
  from 
  the 
  earliest 
  uranium 
  minerals, 
  

   i. 
  e., 
  about 
  1,500 
  million 
  years. 
  

  

  