﻿)/ 
  Deep- 
  Sea 
  Sediments, 
  

  

  195 
  

  

  Ooze, 
  is 
  remarkably 
  radioactive. 
  The 
  Globigerina 
  Ooze 
  from 
  

   the 
  Pacific 
  is 
  also 
  somewhat 
  richer 
  than 
  Atlantic 
  Ooze. 
  The 
  

   manganese 
  nodules 
  from 
  the 
  central 
  Pacific 
  are, 
  again, 
  rich 
  

   in 
  radium. 
  The 
  radioactivity 
  of 
  the 
  Blue 
  Mud 
  of 
  the 
  Conti- 
  

   nental 
  border 
  region 
  is 
  on 
  the 
  other 
  hand 
  comparable 
  with 
  

   that 
  of 
  some 
  ordinary 
  sedimentary 
  rocks. 
  There 
  is 
  nothing 
  

   specially 
  remarkable 
  about 
  the 
  mud 
  from 
  the 
  Volcanic 
  Island. 
  

   With 
  the 
  result 
  for 
  the 
  Green 
  Sand 
  may 
  be 
  compared 
  one 
  

   which 
  I 
  recently 
  obtained 
  from 
  a 
  Green 
  Sandstone 
  of 
  Werl, 
  

   Westphalia 
  :— 
  4' 
  9 
  X 
  10 
  -12 
  . 
  The 
  Globigerina 
  Oozes 
  may 
  be 
  

   contrasted 
  with 
  a 
  result 
  on 
  Marsupites 
  Chalk 
  which 
  afforded 
  

   4-2 
  xl0~ 
  12 
  . 
  

  

  It 
  may 
  be 
  inferred 
  from 
  the 
  following 
  statement 
  of 
  the 
  

   comparative 
  amounts 
  of 
  radium 
  and 
  calcium 
  carbonate 
  in 
  

   some 
  of 
  the 
  deposits, 
  that 
  the 
  amount 
  of 
  radium 
  increases 
  

   with 
  the 
  antiquity 
  of 
  the 
  sediment. 
  This 
  appears 
  from 
  the 
  

   inverse 
  relation 
  of 
  the 
  quantities. 
  

  

  

  Calcium 
  Carbonate 
  

  

  Eadium 
  

  

  

  per 
  cent. 
  

  

  xio" 
  12 
  - 
  

  

  Grlobigerina 
  Ooze, 
  Chall. 
  338 
  

  

  9254 
  

  

  6-7 
  

  

  „ 
  296 
  

  

  64-34 
  

  

  7'4 
  

  

  Eed 
  Clay 
  „ 
  5 
  

  

  1200 
  

  

  15-4 
  

  

  „ 
  276 
  

  

  28-28 
  

  

  52-6 
  

  

  Eadiolarian 
  Ooze 
  „ 
  272 
  

  

  10-19 
  

  

  22-8 
  

  

  „ 
  274 
  

  

  3-89 
  

  

  50-3 
  

  

  The 
  table 
  shows 
  that 
  the 
  deposits 
  richest 
  in 
  calcium 
  car- 
  

   bonate 
  are 
  poorest 
  in 
  radium. 
  This 
  would 
  follow 
  at 
  once 
  if 
  

   I 
  am 
  correct 
  in 
  assuming 
  that 
  the 
  radium 
  may 
  reach 
  the 
  

   bottom 
  precipitated 
  in 
  decomposing 
  organic 
  matter, 
  for 
  in 
  

   the 
  greater 
  depths 
  there 
  would 
  be 
  a 
  diminished 
  quantity 
  of 
  

   calcareous 
  matter 
  accompanying 
  the 
  precipitated 
  radium. 
  

   Thus 
  the 
  concentration 
  of 
  the 
  radium 
  would 
  depend 
  upon 
  the 
  

   supply 
  of 
  organic 
  materials 
  from 
  above, 
  and 
  at 
  the 
  same 
  time 
  

   would 
  be 
  the 
  greater 
  when 
  the 
  conditions 
  were 
  such 
  as 
  to 
  

   reduce 
  the 
  amount 
  of 
  associated 
  calcium 
  carbonate. 
  The 
  

   intensity 
  of 
  the 
  latter 
  conditions 
  determines 
  to 
  a 
  great 
  extent 
  

   the 
  rate 
  of 
  growth. 
  The 
  more 
  slowly 
  accumulating 
  sediments 
  

   would 
  thus 
  necessarily 
  become 
  the 
  richest 
  in 
  radioactive 
  

   matter, 
  

  

  