﻿402 
  Prof. 
  J. 
  Jolj 
  on 
  the 
  

  

  fact 
  is 
  that 
  the 
  limiting 
  volume 
  attained 
  by 
  the 
  emanation 
  is 
  

   so 
  small 
  that 
  its 
  genesis 
  within 
  even 
  the 
  smallest 
  solid 
  or 
  

   quasi-solid 
  particle 
  may 
  render 
  its 
  subsequent 
  abstraction 
  

   impossible. 
  

  

  The 
  mean 
  of 
  the 
  above 
  additional 
  experiments 
  is 
  ^'Q, 
  and 
  

   if 
  the 
  results 
  obtained 
  before 
  filtering 
  are 
  accepted 
  the 
  mean 
  

   is 
  5' 
  6. 
  The 
  waters 
  are, 
  all 
  but 
  one, 
  oceanic. 
  This 
  single 
  

   exception 
  is 
  of 
  interest. 
  It 
  was 
  taken 
  at 
  flood 
  tide 
  at 
  Valentia. 
  

   It 
  remained 
  in 
  the 
  flask 
  a 
  considerable 
  time 
  before 
  testing 
  

   and 
  then 
  showed 
  a 
  very 
  consistent 
  yield 
  of 
  emanation 
  on 
  

   successive 
  experiments. 
  It 
  appears 
  to 
  indicate 
  that 
  coastal 
  

   waters 
  are 
  not 
  invariably 
  of 
  high 
  radioactivity. 
  

  

  The 
  foregoing 
  figures 
  enable 
  us 
  to 
  estimate 
  more 
  particu- 
  

   larly 
  the 
  discrepancy 
  between 
  Eve's 
  results 
  and 
  my 
  own. 
  

   Eve 
  makes 
  comparison 
  between 
  the 
  mean 
  of 
  all 
  my 
  

   determinations 
  as 
  given 
  in 
  my 
  British 
  Association 
  Address 
  

   (16*0) 
  and 
  that 
  of 
  his 
  own 
  recent 
  observations 
  (0*9). 
  This, 
  

   as 
  he 
  points 
  out, 
  gives 
  a 
  ratio 
  of 
  about 
  17 
  to 
  1. 
  Among 
  

   the 
  results 
  included 
  in 
  my 
  mean 
  are 
  several 
  high 
  coastal 
  

   waters 
  : 
  omitting 
  these 
  the 
  mean 
  is 
  11*3. 
  

  

  There 
  is, 
  however, 
  no 
  improbability 
  in 
  the 
  assumption 
  that 
  

   Eve 
  is 
  dealing 
  with 
  waters 
  more 
  aptly 
  compared 
  with 
  those 
  

   which 
  enter 
  largely 
  into 
  my 
  results 
  and 
  in 
  which 
  the 
  radium- 
  

   content 
  is 
  expressed 
  as 
  less 
  than 
  10. 
  Thus 
  the 
  mean 
  of 
  my 
  

   observations 
  for 
  across- 
  Atlantic 
  water 
  is 
  — 
  if 
  filtration 
  results 
  

   be 
  excluded 
  — 
  6*7. 
  Many 
  of 
  my 
  measurements 
  range 
  about 
  

   4 
  to 
  7. 
  One 
  is 
  as 
  low 
  as 
  2'2. 
  Such 
  may 
  be 
  regarded 
  

   as 
  from 
  3 
  to 
  7 
  times 
  those 
  of 
  Eve. 
  Mr. 
  Strutf's 
  pioneer 
  

   observation 
  upon 
  sea-salt 
  gives 
  2*4. 
  It 
  is 
  very 
  probable 
  that 
  

   sea-salt 
  in 
  course 
  of 
  preparation 
  loses 
  some 
  of 
  the 
  more 
  

   readily 
  precipitated 
  substances, 
  among 
  which 
  is 
  radium. 
  

   With 
  this 
  probability 
  in 
  view 
  Mr. 
  Strutt^s 
  observation 
  is 
  in 
  

   fair 
  agreement 
  with 
  my 
  lower 
  results. 
  

  

  With 
  regard 
  to 
  the 
  higher 
  results 
  embodied 
  in 
  my 
  list, 
  

   there 
  is, 
  I 
  believe, 
  difficulty 
  in 
  any 
  explanation 
  but 
  that 
  

   which 
  admits 
  their 
  essential 
  veracity. 
  A 
  comparison 
  of 
  (15) 
  

   and 
  (16) 
  is 
  instructive 
  in 
  this 
  connexion. 
  Here 
  every 
  

   circumstance 
  as 
  regards 
  precautions, 
  the 
  nature 
  of 
  the 
  bottles 
  

   and 
  the 
  conditions 
  of 
  collecting 
  are 
  alike. 
  Upon 
  their 
  receipt 
  

   the 
  water 
  was 
  transferred 
  without 
  any 
  further 
  manipulation 
  

   into 
  the 
  flasks 
  ; 
  equal 
  quantities 
  of 
  acid 
  added 
  from 
  the 
  same 
  

   bottle, 
  and 
  in 
  due 
  time 
  the 
  radium 
  determined 
  under 
  the 
  

   same 
  experimental 
  conditions. 
  If 
  the 
  difference 
  in 
  the 
  

   results 
  is 
  not 
  due 
  to 
  a 
  difference 
  in 
  the 
  original 
  radium- 
  

   content 
  of 
  the 
  water, 
  we 
  have 
  to 
  assume 
  either 
  that 
  the 
  water 
  

   which 
  reads 
  lowest 
  is 
  really 
  as 
  rich 
  in 
  radium 
  as 
  the 
  other, 
  

  

  