﻿JRays 
  and 
  Product 
  of 
  Uranium 
  X. 
  865 
  

  

  These 
  tests, 
  therefore, 
  although 
  still 
  incomplete, 
  cover 
  for 
  

   different 
  preparations 
  the 
  period 
  from 
  the 
  start 
  up 
  to 
  nearly 
  

   a 
  year 
  in 
  the 
  case 
  of 
  the 
  main 
  preparations, 
  and 
  for 
  con- 
  

   siderably 
  longer 
  for 
  weaker 
  preparations. 
  They 
  have 
  given 
  

   no 
  evidence 
  of 
  the 
  growth 
  of 
  an 
  a-radiation 
  at 
  any 
  time 
  

   during 
  this 
  period. 
  They 
  all 
  show 
  a 
  considerable 
  constant 
  

   a-radiation, 
  but 
  in 
  all 
  it 
  appears 
  to 
  be 
  due 
  to 
  a 
  body 
  present 
  

   from 
  the 
  start, 
  unconnected 
  genetically 
  with 
  uranium 
  X. 
  

   The 
  statement 
  of 
  Keetmann, 
  that 
  uranium 
  X 
  and 
  the 
  parent 
  

   of 
  radium 
  are 
  identical 
  in 
  chemical 
  behaviour 
  and 
  are 
  always 
  

   separated 
  together, 
  would 
  explain 
  the 
  presence 
  of 
  the 
  a-ray 
  

   body 
  in 
  all 
  the 
  preparations 
  so 
  far 
  kept 
  under 
  observation. 
  

   The 
  conclusion 
  seems 
  to 
  be 
  justified 
  that 
  the 
  parent 
  of 
  radium 
  

   is 
  not 
  the 
  direct 
  product 
  of 
  uranium 
  X, 
  and 
  the 
  question 
  

   now 
  arises 
  whether 
  it 
  can 
  be 
  considered 
  a 
  product 
  of 
  uranium 
  

   X 
  at 
  all. 
  Even 
  if 
  there 
  was 
  a 
  new 
  intermediate 
  product 
  in 
  

   the 
  series 
  '* 
  uranium 
  A/' 
  with 
  a 
  period 
  of 
  a 
  many 
  years, 
  

   provided 
  there 
  was 
  but 
  one, 
  some 
  indication 
  of 
  growth 
  

   of 
  a-rays 
  should 
  before 
  now 
  have 
  been 
  obtained 
  in 
  these 
  

   experiments. 
  For 
  it 
  must 
  be 
  remembered 
  that 
  its 
  existence 
  

   would 
  greatly 
  reduce, 
  as 
  explained 
  in 
  the 
  last 
  paper, 
  

   the 
  period 
  of 
  the 
  parent 
  of 
  radium, 
  as 
  calculated 
  from 
  the 
  

   measurements 
  of 
  the 
  rate 
  of 
  growth 
  of 
  radium, 
  and 
  so 
  

   Avoidd 
  increase 
  correspondinojly 
  the 
  growth 
  of 
  a-rays 
  ulti- 
  

   mately 
  to 
  be 
  expected- 
  The 
  subsequent 
  history 
  of 
  the 
  

   preparations 
  may 
  be 
  expected 
  to 
  throw 
  further 
  light 
  on 
  this 
  

   question. 
  

  

  The 
  results 
  so 
  far 
  obtained 
  are 
  difficult 
  to 
  reconcile 
  with 
  

   the 
  experiments 
  on 
  the 
  rate 
  of 
  production 
  of 
  radium 
  from 
  

   uranium, 
  on 
  the 
  assumption 
  that 
  the 
  parent 
  of 
  radium 
  is 
  a 
  

   product 
  of 
  uranium 
  X. 
  There 
  is 
  no 
  proof 
  of 
  this, 
  though 
  on 
  

   account 
  of 
  the 
  intense 
  character 
  of 
  the 
  y9-rays 
  of 
  uranium, 
  it 
  

   seems 
  natural 
  to 
  suppose 
  that 
  uranium 
  X, 
  the 
  y3-ray-pro^ 
  

   diicing 
  body, 
  is 
  in 
  the 
  main 
  radium 
  series 
  rather 
  than 
  in 
  that 
  

   of 
  actinium. 
  

  

  Physical 
  Chemistry 
  Laboratory, 
  

  

  University 
  of 
  Glassfow. 
  

  

  October 
  1909.^ 
  

  

  