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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  1922. 
  

  

  raises 
  a 
  vital 
  question 
  into 
  which 
  it 
  is 
  necessary 
  to 
  inquire 
  before 
  

   assuming 
  the 
  practical 
  non 
  reversibility 
  of 
  the 
  sodium 
  solutions. 
  It 
  

   is 
  already 
  well 
  recognized 
  that 
  a 
  part 
  of 
  this 
  sustained 
  productive- 
  

   ness 
  is 
  due 
  to 
  sea 
  winds 
  which 
  carry 
  salt 
  inland 
  from 
  the 
  ocean. 
  This 
  

   salt 
  is 
  thus 
  counted 
  as 
  many 
  times 
  as 
  it 
  is 
  carried 
  back. 
  An 
  endeavor 
  

   has 
  been 
  made 
  to 
  estimate 
  and 
  make 
  allowance 
  for 
  this 
  by 
  taking 
  the 
  

   increase 
  of 
  salt 
  solutions 
  near 
  the 
  ocean 
  as 
  a 
  criterion. 
  It 
  has 
  also 
  

   been 
  recognized 
  that 
  salt 
  solutions 
  are 
  entrapped 
  in 
  the 
  pores 
  of 
  the 
  

   sediments 
  as 
  they 
  are 
  laid 
  down 
  under 
  the 
  sea, 
  and 
  that 
  when 
  the 
  beds 
  

   are 
  afterwards 
  raised 
  above 
  the 
  sea 
  level 
  these 
  solutions 
  are 
  drained 
  

   into 
  the 
  streams 
  and 
  counted 
  again 
  as 
  salts 
  from 
  the 
  land. 
  The 
  

   amount 
  of 
  duplication 
  involved 
  in 
  this 
  depends 
  on 
  the 
  ability 
  of 
  the 
  

   rocks 
  to 
  hold 
  salt 
  water 
  mechanically 
  in 
  their 
  pores, 
  and 
  correction 
  

   has 
  been 
  sought 
  by 
  estimating 
  their 
  porosity 
  and 
  discounting 
  for 
  it. 
  

   Sandstones 
  usually 
  have 
  the 
  highest 
  porosity 
  and 
  limestones 
  come 
  

   next, 
  while 
  shales 
  are 
  relatively 
  close-textured 
  and 
  impervious, 
  but 
  

   still 
  the 
  shales 
  are 
  exceptionally 
  productive. 
  So, 
  also, 
  it 
  has 
  been 
  

   recognized 
  that 
  beds 
  of 
  rock 
  salt 
  occur 
  in 
  the 
  stratified 
  series, 
  but 
  

   these 
  are 
  held 
  to 
  be 
  relatively 
  unimportant. 
  So 
  still 
  further 
  some 
  

   particles 
  of 
  the 
  original 
  rock 
  may 
  remain 
  undisintegrated 
  ; 
  so, 
  too, 
  

   fresh 
  particles 
  may 
  be 
  cut 
  away 
  from 
  exposed 
  rocks 
  by 
  wind 
  blast 
  

   and 
  widely 
  though 
  sparsely 
  distributed. 
  But 
  when 
  the 
  modifying 
  

   effects 
  of 
  all 
  these 
  have 
  been 
  recognized 
  and 
  discounted, 
  there 
  still 
  

   remains 
  a 
  serious 
  source 
  of 
  double 
  counting 
  of 
  sodium 
  which 
  we 
  must 
  

   consider 
  presently. 
  

  

  4. 
  The 
  ratio 
  of 
  chlorine 
  to 
  sodium 
  is 
  a 
  crucial 
  matter, 
  recognized 
  

   but 
  not 
  sufficiently 
  emphasized. 
  Inspection 
  of 
  the 
  drainage 
  from 
  

   regions 
  of 
  igneous 
  rocks 
  shows 
  that 
  the 
  chlorine 
  is 
  relatively 
  low 
  and 
  

   the 
  sodium 
  relatively 
  high 
  compared 
  with 
  the 
  ratio 
  of 
  these 
  ele- 
  

   ments 
  in 
  the 
  ocean, 
  which 
  is 
  about 
  1.8 
  chlorine 
  to 
  1 
  sodium. 
  The 
  rela- 
  

   tive 
  deficiency 
  of 
  chlorine 
  in 
  the 
  drainage 
  from 
  the 
  very 
  rocks 
  that 
  

   are 
  assumed 
  to 
  be 
  the 
  ultimate 
  source 
  of 
  the 
  salt 
  solutions 
  raises 
  a 
  

   fundamental 
  issue. 
  

  

  5. 
  In 
  view 
  of 
  this, 
  let 
  us 
  make 
  our 
  inspection 
  as 
  sweeping 
  as 
  pos- 
  

   sible. 
  Let 
  us 
  compare 
  the 
  ratio 
  of 
  sodium 
  to 
  chlorine 
  in 
  the 
  ocean 
  

   with 
  the 
  ratio 
  found 
  in 
  the 
  average 
  igneous 
  rock 
  of 
  the 
  whole 
  

   " 
  crust." 
  The 
  latest 
  and 
  most 
  authoritative 
  determination 
  of 
  the 
  

   chemical 
  composition 
  of 
  the 
  igneous 
  rocks 
  is 
  that 
  of 
  Clarke 
  and 
  

   Washington, 
  which 
  gives 
  the 
  mean 
  sodium 
  content 
  as 
  2.83 
  and 
  that 
  

   of 
  chlorine 
  as 
  0.096. 
  17 
  From 
  this 
  it 
  appears 
  that 
  the 
  mean 
  per 
  cent, 
  

  

  17 
  Frank 
  W. 
  Clarke 
  and 
  Henry 
  S. 
  Washington, 
  U. 
  S. 
  Geol. 
  Surv. 
  and 
  Geophys. 
  Lab., 
  

   Carnegie 
  Institution 
  of 
  Washington, 
  " 
  The 
  average 
  composition 
  of 
  igneous 
  rocks," 
  Proc. 
  

   Nat. 
  Acad, 
  of 
  Sci., 
  vol. 
  8, 
  no. 
  3 
  (May, 
  1922), 
  pp. 
  108-13. 
  In 
  the 
  paper 
  as 
  read 
  at 
  the 
  

   symposium 
  I 
  used 
  the 
  then 
  latest 
  and 
  most 
  authoritative 
  figures, 
  viz, 
  those 
  of 
  H. 
  S. 
  

   Washington, 
  " 
  The 
  chemistry 
  of 
  the 
  earth's 
  crust," 
  Jour. 
  Franklin 
  Inst., 
  in 
  which 
  the 
  

   sodium 
  was 
  given 
  as 
  2.85 
  and 
  the 
  chlorine 
  as 
  0.055. 
  

  

  