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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1922. 
  

  

  mentary 
  beds, 
  particularly 
  when 
  deformations 
  take 
  place 
  or 
  igneous 
  

   and 
  metamorphic 
  actions 
  follow, 
  but 
  we 
  need 
  not 
  dwell 
  on 
  these. 
  

  

  The 
  cycles 
  of 
  chlorine. 
  — 
  The 
  climax 
  of 
  the 
  solvent 
  actions 
  that 
  

   enrich 
  the 
  sea 
  is 
  reached 
  in 
  the 
  cycles 
  of 
  chlorine, 
  but 
  only 
  a 
  passing 
  

   word 
  can 
  be 
  given 
  to 
  these. 
  The 
  tenor 
  of 
  experiments 
  with 
  soils 
  

   indicates 
  that 
  chlorine 
  remains 
  more 
  persistently 
  in 
  solution 
  than 
  the 
  

   sodium 
  and 
  associated 
  substances. 
  As 
  the 
  cycles 
  of 
  each 
  substance 
  

   spring 
  from 
  its 
  own 
  nature 
  and 
  the 
  conditions 
  it 
  encounters, 
  the 
  very 
  

   high 
  preponderance 
  of 
  chlorine 
  over 
  sodium 
  in 
  the 
  ocean 
  finds 
  its 
  

   chief 
  explanation 
  in 
  this 
  more 
  persistent 
  solubility. 
  Its 
  proportion 
  

   in 
  average 
  rock 
  is 
  only 
  a 
  conditioning 
  factor 
  and 
  is 
  not 
  the 
  chief 
  

   controlling 
  influence. 
  When 
  compared 
  with 
  sodium, 
  which 
  is 
  much 
  

   more 
  abundant 
  in 
  the 
  igneous 
  rocks 
  and 
  indeed 
  in 
  the 
  whole 
  sub- 
  

   stance 
  of 
  the 
  outer 
  10 
  or 
  20 
  miles 
  of 
  the 
  earth 
  shell, 
  atmosphere, 
  

   and 
  hydrosphere 
  included, 
  27 
  the 
  logical 
  conclusion 
  is 
  that 
  the 
  cycles 
  

   of 
  chlorine 
  have 
  always 
  had 
  a 
  much 
  larger 
  liquid 
  phase 
  than 
  those 
  of 
  

   sodium, 
  and 
  that 
  this 
  has 
  been 
  cumulative 
  through 
  the 
  ages. 
  Chlo- 
  

   rine 
  is 
  better 
  fitted 
  than 
  sodium 
  to 
  be 
  used 
  as 
  a 
  criterion 
  of 
  age, 
  but 
  

   even 
  in 
  this 
  case 
  there 
  are 
  formidable 
  difficulties. 
  Both 
  sodium 
  and 
  

   chlorine 
  and 
  all 
  the 
  other 
  constituents, 
  as 
  already 
  noted, 
  have 
  their 
  

   own 
  histories 
  which 
  are 
  difficult 
  to 
  disentangle. 
  As 
  Roger 
  Bell 
  

   neatly 
  puts 
  it: 
  "There 
  are 
  as 
  many 
  histories 
  to 
  be 
  written 
  about 
  the 
  

   waters 
  as 
  there 
  are 
  kinds 
  of 
  sediment." 
  28 
  There 
  would 
  be 
  an 
  ocean 
  

   highly 
  charged 
  with 
  chlorides 
  if 
  there 
  were 
  no 
  sodium 
  in 
  the 
  earth 
  at 
  

   all. 
  So 
  there 
  would 
  be 
  an 
  ocean 
  highly 
  charged 
  with 
  sodium 
  solu- 
  

   tions 
  if 
  there 
  were 
  no 
  chlorine 
  in 
  the 
  earth. 
  The 
  status 
  of 
  the 
  ocean 
  

   at 
  any 
  time 
  is 
  simply 
  the 
  equation 
  of 
  the 
  solution 
  phases 
  of 
  the 
  ante- 
  

   cedent 
  cycles 
  of 
  its 
  constituents, 
  all 
  of 
  which 
  have 
  passed 
  through 
  

   long, 
  complex, 
  more 
  or 
  less 
  individual 
  histories. 
  In 
  the 
  tedious 
  work 
  

   of 
  their 
  disentanglement 
  the 
  older 
  and 
  simpler 
  geochemical 
  notions 
  

   will 
  not 
  answer; 
  the 
  newer 
  principles 
  of 
  chemistry, 
  physics, 
  and 
  

   geology 
  are 
  indispensable. 
  

  

  Conclusions. 
  — 
  Our 
  finding, 
  then, 
  in 
  respect 
  to 
  the 
  age 
  of 
  the 
  earth 
  

   from 
  the 
  geological 
  viewpoint 
  is 
  this 
  : 
  

  

  1. 
  Estimates 
  of 
  time 
  based 
  on 
  the 
  well-preserved 
  series 
  of 
  geologi- 
  

   cal 
  sediments 
  will, 
  when 
  adequately 
  corrected, 
  probably 
  fall 
  into 
  

   harmony 
  with 
  the 
  revised 
  deductions 
  from 
  paleontology, 
  radio-activ- 
  

   ity, 
  and 
  astronomy, 
  so 
  far 
  as 
  these 
  cover 
  the 
  same 
  ground. 
  

  

  2. 
  The 
  distorted 
  and 
  metamorphosed 
  terranes 
  below 
  the 
  well-pre- 
  

   served 
  series 
  of 
  sediments 
  do 
  not 
  disclose 
  the 
  starting 
  point 
  of 
  sedi- 
  

   mentation. 
  The 
  sediments 
  can 
  therefore 
  give 
  no 
  verdict 
  on 
  the 
  total 
  

   age 
  of 
  the 
  earth; 
  they 
  are 
  great 
  enough, 
  however, 
  to 
  show 
  that 
  the 
  

   earth 
  is 
  very 
  old. 
  

  

  * 
  Clarke 
  and 
  Washington, 
  ibid., 
  p, 
  114. 
  * 
  Personal 
  communication. 
  

  

  