﻿Radium- 
  Content 
  of 
  Sea 
  Water. 
  405 
  

  

  the 
  table 
  I 
  am, 
  therefore, 
  responsible. 
  Although 
  some 
  part 
  — 
  

   presumably 
  a 
  small 
  part 
  — 
  of 
  the 
  ionization 
  may 
  be 
  ascribable 
  

   to 
  thorium 
  emanation, 
  the 
  assumptions 
  made 
  in 
  my 
  estimate 
  

   of 
  the 
  radium 
  are 
  all 
  on 
  the 
  side 
  of 
  reducing 
  the 
  final 
  result. 
  

   The 
  author 
  offers 
  no 
  opinion 
  as 
  to 
  the 
  origin 
  of 
  the 
  

   emanation 
  save 
  that 
  it 
  can 
  only 
  in 
  the 
  very 
  smallest 
  degree 
  

   be 
  ascribed 
  to 
  the 
  atmosphere, 
  and 
  that 
  his 
  highest 
  result 
  

   being 
  obtained 
  near 
  the 
  volcanic 
  island 
  of 
  Fernando 
  Noronha, 
  

   in 
  such 
  a 
  locality 
  the 
  solution 
  of 
  active 
  materials 
  and 
  the 
  

   absorption 
  of 
  gases 
  emitted 
  beneath 
  the 
  sea 
  may 
  be 
  of 
  

   influence. 
  A 
  little 
  consideration 
  will, 
  I 
  think, 
  show 
  that 
  the 
  

   greater 
  part 
  of 
  the 
  emanation 
  must 
  come 
  from 
  radium 
  con- 
  

   tained 
  in 
  the 
  water. 
  We 
  arrive 
  at 
  this 
  result 
  by 
  a 
  process 
  of 
  

   exclusion. 
  If 
  we 
  assume 
  the 
  emanation 
  comes 
  from 
  the 
  

   atmosphere 
  then 
  we 
  not 
  only 
  greatly 
  intensify 
  the 
  difficulties 
  

   upon 
  which 
  Dr. 
  Eve 
  has 
  been 
  dwelling 
  but 
  we 
  find 
  the 
  

   absence 
  of 
  emanation, 
  as 
  determined 
  by 
  McLennan, 
  from 
  the 
  

   waters 
  of 
  Lake 
  Ontario, 
  inexplicable 
  *. 
  The 
  anomaly 
  would 
  

   be 
  the 
  more 
  remarkable 
  in 
  view 
  of 
  Kofler's 
  recent 
  researchas 
  

   (Phys. 
  Zeit. 
  Jan. 
  1, 
  1908) 
  showing 
  that 
  the 
  emanation 
  of 
  

   radium 
  is 
  more 
  soluble 
  in 
  fresh 
  than 
  in 
  salt 
  water. 
  If 
  we 
  

   ascribe 
  the 
  emanation 
  to 
  the 
  globigerina 
  ooze 
  about 
  two 
  miles 
  

   beneath, 
  difficulties 
  of 
  a 
  quantitative 
  character, 
  which 
  I 
  

   believe 
  are 
  insurmountable, 
  present 
  themselves. 
  The 
  quantity 
  

   of 
  emanation 
  near 
  the 
  equator, 
  as 
  represented 
  by 
  the 
  equivalent 
  

   radium, 
  is 
  about 
  300 
  times 
  what 
  has 
  been 
  observed 
  in 
  the 
  

   atmosphere. 
  But 
  on 
  the 
  ocean 
  floor 
  the 
  porosity, 
  and 
  the 
  con- 
  

   vective 
  circulation 
  of 
  gases, 
  such 
  as 
  facilitate 
  its 
  liberation 
  from 
  

   the 
  soils, 
  cannot 
  exist. 
  The 
  emanation, 
  presumably, 
  can 
  only 
  

   move 
  outwards 
  on 
  slow 
  diffusive 
  movements, 
  and 
  when 
  it 
  has 
  

   been 
  liberated 
  from 
  the 
  mud 
  its 
  further 
  motion 
  must 
  be 
  regu- 
  

   lated 
  by 
  the 
  leisurely 
  creeping 
  of 
  deep-sea 
  currents. 
  However, 
  

   in 
  order 
  to 
  account 
  for 
  the 
  sustained 
  radioactivity 
  of 
  the 
  surface 
  

   waters 
  we 
  evidently 
  must 
  assume 
  a 
  steady 
  flow 
  of 
  emanation- 
  

   rich 
  water 
  from 
  beneath 
  ; 
  and 
  thus 
  we 
  have 
  to 
  find 
  some 
  

   source 
  from 
  which 
  the 
  emanation, 
  continually 
  perishing 
  

   throughout 
  the 
  entire 
  depth 
  of 
  the 
  ocean, 
  may 
  be 
  supplied. 
  

   Taking 
  the 
  depth 
  at 
  2000 
  fathoms 
  and 
  the 
  radium 
  -content 
  of 
  

   the 
  ooze 
  as 
  7 
  x 
  10~^^ 
  gram 
  per 
  gram, 
  the 
  continuous 
  liberation 
  

   of 
  all 
  the 
  emanation 
  from 
  a 
  depth 
  of 
  not 
  less 
  than 
  5 
  metres 
  of 
  

   ooze, 
  and 
  its 
  distribution 
  without 
  loss 
  throughout 
  the 
  overlying 
  

   water, 
  must 
  be 
  assumed 
  — 
  conditions 
  which 
  do 
  not 
  merit 
  dis- 
  

   cussion. 
  Unless 
  there 
  exist 
  bottom 
  currents 
  having 
  a 
  velocity 
  

   adequate 
  to 
  concentrate 
  the 
  emanation 
  escaping 
  from 
  some 
  

  

  * 
  C. 
  S. 
  Wright, 
  Phil. 
  Mag. 
  Feb. 
  1909, 
  p. 
  316. 
  

   Pha. 
  Mag. 
  S. 
  6. 
  Vol. 
  18. 
  No. 
  105. 
  Sept. 
  1909. 
  2 
  E 
  

  

  