﻿between 
  Uranium 
  and 
  Radium, 
  G33 
  

  

  tests 
  will 
  be 
  carried 
  out 
  without 
  the 
  pump 
  in 
  the 
  manner 
  

   previously 
  described 
  (loc. 
  cit. 
  II. 
  p. 
  281). 
  All 
  the 
  other 
  

   radium 
  tests 
  described 
  in 
  the 
  paper 
  are 
  carried 
  out 
  also 
  in 
  this 
  

   way, 
  as 
  it 
  involves 
  less 
  labour 
  than 
  the 
  pump 
  method. 
  Before 
  

   the 
  results 
  in 
  the 
  main 
  experiments 
  (I. 
  and 
  II.) 
  are 
  described, 
  

   the 
  less 
  important, 
  but 
  gratifying 
  result 
  of 
  Experiment 
  VI. 
  

   will 
  be 
  first 
  dealt 
  with, 
  

  

  Experiment 
  VI. 
  — 
  The 
  residues 
  from 
  the 
  uranium 
  used 
  in 
  

   experiments 
  I. 
  and 
  II. 
  {he. 
  cit. 
  II. 
  pp. 
  285 
  & 
  293), 
  had 
  

   been 
  purified 
  from 
  radium 
  by 
  the 
  original 
  barium 
  sulphate 
  

   method 
  employed 
  in 
  1901, 
  and 
  the 
  quantity 
  of 
  radium 
  then 
  

   present 
  (June 
  20th 
  and 
  July 
  3rd, 
  1907) 
  was 
  found 
  to 
  be 
  

   only 
  4 
  x 
  10~ 
  12 
  gram. 
  In 
  two 
  agreeing 
  consecutive 
  tests 
  on 
  

   May 
  22nd 
  and 
  July 
  1st, 
  1908, 
  the 
  amount 
  of 
  radium 
  found 
  

   was 
  3 
  X 
  10 
  _li 
  gram. 
  Thus 
  in 
  a 
  year 
  the 
  quantity 
  of 
  radium 
  

   had 
  increased 
  about 
  seven 
  times. 
  This 
  establishes, 
  indeed, 
  

   what 
  was 
  all 
  along 
  to 
  be 
  expected, 
  first 
  the 
  existence 
  of 
  a 
  

   radium-producing 
  body 
  in 
  commercial 
  uranium 
  salts, 
  and 
  

   secondly 
  that 
  the 
  original 
  barium 
  sulphate 
  method 
  of 
  purifi- 
  

   cation 
  of 
  uranium 
  from 
  radium 
  does 
  not 
  remove 
  all 
  this 
  

   substance. 
  Though, 
  in 
  the 
  present 
  state 
  of 
  the 
  subject, 
  not 
  

   of 
  much 
  importance, 
  these 
  results 
  are 
  personally 
  very 
  grati- 
  

   fying 
  as 
  they 
  bear 
  out 
  the 
  original 
  observation 
  of 
  a 
  growth 
  

   of 
  radium, 
  which 
  was 
  ascribed 
  to 
  experimental 
  error 
  by 
  a 
  

   subsequent 
  investigator 
  who 
  employed 
  one 
  tenth 
  part 
  of 
  the 
  

   amount 
  of 
  uranium, 
  a 
  shorter 
  period 
  of 
  observation, 
  and 
  a 
  

   different 
  method 
  of 
  purification. 
  

  

  The 
  original 
  experiment 
  was 
  of 
  necessity 
  terminated, 
  as 
  it 
  

   was 
  necessary 
  to 
  prove 
  that 
  the 
  sulphuric 
  acid 
  present, 
  by 
  

   causing 
  the 
  radium 
  formed 
  to 
  assume 
  the 
  non-emanating 
  

   condition, 
  was 
  not 
  interfering 
  with 
  the 
  results. 
  The 
  solution 
  

   of 
  the 
  barium 
  sulphate 
  precipitate, 
  used 
  at 
  the 
  end 
  of 
  the 
  

   experiment 
  to 
  precipitate 
  the 
  radium 
  formed, 
  has 
  however 
  

   been 
  preserved 
  unchanged. 
  In 
  1905 
  the 
  leak 
  it 
  produced 
  in 
  

   an 
  electroscope, 
  by 
  the 
  bubbling 
  test, 
  was 
  much 
  less 
  than 
  

   when 
  tested 
  by 
  the 
  same 
  method 
  a 
  few 
  w 
  r 
  eeks 
  ago. 
  It 
  is 
  

   therefore 
  being 
  examined 
  to 
  see 
  if 
  it 
  does 
  not 
  contain 
  some 
  of 
  

   the 
  original 
  radium-producing 
  substance 
  precipitated 
  with 
  

   the 
  barium 
  sulphate. 
  

  

  'Che 
  amount 
  of 
  the 
  radium 
  parent 
  in 
  commercial 
  uranium 
  

   salts 
  probably 
  varies 
  very 
  much. 
  In 
  some 
  commercial 
  uranyl 
  

   nitrate 
  recently 
  purchased 
  the 
  total 
  impurities 
  present 
  

   amounted 
  only 
  to 
  a 
  few 
  tenths 
  of 
  a 
  per 
  cent., 
  whereas 
  from 
  

   one 
  of 
  the 
  kilograms 
  used 
  in 
  the 
  earlier 
  work 
  over 
  200 
  grams 
  

   of 
  the 
  sulphate 
  of 
  an 
  alkali-metal 
  were 
  extracted. 
  

  

  The 
  very 
  first 
  uranyl 
  nitrate 
  examined, 
  in 
  1903, 
  was 
  

  

  