﻿Bays 
  and 
  Product 
  of 
  Uraniani 
  X. 
  859 
  

  

  fieLl 
  of 
  investigation 
  wliicli 
  benr 
  also 
  n})on 
  the 
  same 
  problem. 
  

   Attempts 
  have 
  been 
  made 
  to 
  determine 
  whether, 
  during 
  the 
  

   decay 
  of 
  the 
  /3-radiation 
  of 
  the 
  intensely 
  active 
  preparations 
  

   of 
  uranium 
  X, 
  separated 
  with 
  the 
  help 
  of 
  Mr. 
  Russell 
  (Phil. 
  

   Mag. 
  Oct. 
  1909, 
  p. 
  620) 
  from 
  50 
  kilograms 
  of 
  pure 
  uranyl 
  

   nitrate, 
  there 
  occurred 
  the 
  growth 
  of 
  a 
  feeble 
  a-radiation 
  

   increasing 
  concomitantly 
  as 
  the 
  other 
  decayed. 
  This 
  is 
  to 
  

   be 
  expected 
  from 
  the 
  work 
  of 
  Bolt 
  wood, 
  Keetmann 
  and 
  

   others, 
  who 
  have 
  shown 
  that 
  the 
  direct 
  parent 
  of 
  radium 
  

   gives 
  an 
  a-radiation, 
  provided 
  that 
  it 
  is 
  the 
  direct 
  product 
  of 
  

   uranium 
  X. 
  The 
  work 
  was 
  started 
  in 
  the 
  hope 
  that 
  inter- 
  

   mediate 
  bodies 
  intervened, 
  and 
  that 
  the 
  growth 
  of 
  a-rays 
  

   would 
  occur 
  long 
  enough 
  after 
  the 
  yS-rays 
  of 
  the 
  uranium 
  X 
  

   had 
  decayed 
  to 
  be 
  detectable 
  by 
  onlinary 
  measurements. 
  

   But 
  through 
  the 
  generosity 
  of 
  the 
  friend 
  who 
  provided 
  the 
  

   uraninm 
  a 
  powerful 
  electroiuagnet 
  of 
  the 
  Du 
  Bois 
  type 
  was 
  

   acquired, 
  and 
  with 
  this 
  it 
  was 
  attempted 
  to 
  deviate 
  the 
  

   y8-rays 
  of 
  the 
  uranium 
  X, 
  so 
  that 
  measurements 
  of 
  the 
  a-ravs 
  

   of 
  the 
  preparations 
  could 
  be 
  taken 
  from 
  the 
  start. 
  The 
  

   problem 
  proved 
  a 
  difficult 
  one, 
  but 
  gradually 
  the 
  experi- 
  

   mental 
  methods 
  have 
  been 
  perfected, 
  so 
  that 
  now 
  it 
  is 
  claimed 
  

   that 
  they 
  are 
  sufficiently 
  delicate 
  to 
  detect 
  such 
  a 
  growth 
  of 
  

   a-rays 
  if 
  it 
  occurred 
  in 
  the 
  intensely 
  active 
  uranium 
  X 
  

   preparations 
  investigated 
  to 
  the 
  extent 
  to 
  be 
  expected 
  from 
  

   theory. 
  Much 
  remains 
  unaccountable 
  in 
  connexion 
  with 
  

   these 
  experiments, 
  but 
  they 
  appear 
  to 
  have 
  definitely 
  

   answered 
  the 
  main 
  question 
  in 
  the 
  negative. 
  No 
  production 
  

   of 
  a-rays, 
  such 
  as 
  is 
  to 
  be 
  expected 
  from 
  theory, 
  has 
  occurred, 
  

   and 
  therefore 
  it 
  does 
  not 
  seem 
  possible 
  that 
  the 
  direct 
  parent 
  

   of 
  radium 
  can 
  be 
  the 
  direct 
  product 
  of 
  uranium 
  X. 
  The 
  

   experiments 
  indeed 
  raise 
  the 
  further 
  question 
  whether 
  the 
  

   parent 
  of 
  radium 
  can 
  be 
  a 
  product 
  of 
  uranium 
  X 
  at 
  all, 
  but 
  

   are 
  not 
  yet 
  far 
  enough 
  ad\anced 
  to 
  be 
  conclusive. 
  

  

  Were 
  the 
  parent 
  of 
  radium 
  a 
  product 
  of 
  uranium 
  X 
  the 
  

   number 
  of 
  a-particles 
  it 
  emits 
  should 
  either 
  be 
  equal 
  to, 
  or 
  

   on^'-half 
  of, 
  the 
  number 
  emitted 
  by 
  the 
  uranium 
  in 
  equilibrium 
  

   with 
  it, 
  according 
  as 
  one 
  or 
  two 
  aj-particles 
  are 
  given 
  off 
  

   from 
  uranium. 
  The 
  latter 
  assumption 
  will 
  be 
  made 
  as 
  it 
  

   gives 
  the 
  smaller 
  growth 
  of 
  a-rays 
  theoretically 
  to 
  be 
  

   expected 
  from 
  uranium 
  X. 
  Assuming 
  that 
  the 
  a-activity 
  is 
  

   proportional 
  also 
  to 
  the 
  ranges 
  of 
  the 
  respective 
  a-particles, 
  

   which 
  are 
  2*7 
  and 
  3*5 
  cm., 
  the 
  a-activity 
  of 
  the 
  parent 
  of 
  

   radium 
  will 
  be 
  2' 
  7 
  -f- 
  3*5 
  x 
  0*5, 
  or 
  '38 
  of 
  that 
  of 
  the 
  uranium. 
  

   The 
  period 
  of 
  the 
  parent 
  of 
  radium 
  as 
  deduced 
  in 
  the 
  last 
  

   paper 
  on 
  the 
  assumption 
  that 
  no 
  new 
  intermediate 
  bodies 
  

   exist 
  in 
  the 
  series, 
  is 
  18.500 
  vear<. 
  while 
  that 
  of 
  uranium 
  X 
  

  

  