﻿858 
  Mr. 
  F. 
  SoLldy 
  on 
  the 
  

  

  VIII. 
  Conclusions. 
  

  

  The 
  measurements 
  on 
  the 
  growth 
  of 
  radium 
  in 
  the 
  three 
  

   uranium 
  solutions 
  purified 
  by 
  Mr. 
  T. 
  D. 
  Mackenzie 
  between 
  

   three 
  and 
  four 
  years 
  ago, 
  have 
  shown 
  that 
  in 
  all 
  of 
  them 
  the 
  

   growth 
  of 
  radium 
  is 
  proceeding 
  according 
  to 
  the 
  square 
  of 
  

   the 
  time 
  within 
  the 
  error 
  of 
  measurement. 
  The 
  period 
  of 
  

   the 
  direct 
  parent 
  of 
  radium 
  calculated 
  from 
  these 
  results, 
  on 
  

   the 
  assumption 
  that 
  no 
  other 
  intermediate 
  bodies 
  interven(>, 
  

   is 
  18,500 
  years 
  in 
  the 
  case 
  of 
  the 
  oldest 
  solution 
  for 
  which 
  

   the 
  most 
  complete 
  data 
  are 
  available. 
  But 
  in 
  the 
  solatioii 
  

   prepared 
  last, 
  the 
  total 
  quantity 
  of 
  radium 
  now 
  present 
  is 
  

   less 
  than 
  what 
  would 
  have 
  been 
  produced 
  from 
  the 
  radium, 
  

   assuming 
  the 
  rate 
  of 
  production 
  to 
  have 
  been 
  the 
  same 
  as 
  in 
  

   the 
  first 
  solution. 
  This 
  suggests 
  the 
  existence 
  of 
  at 
  least 
  

   one 
  new 
  product 
  " 
  uranium 
  A 
  " 
  intermediate 
  between 
  

   uranium 
  X 
  and 
  the 
  parent 
  of 
  radium, 
  with 
  the 
  period 
  of 
  the 
  

   order 
  of 
  one 
  year. 
  From 
  a 
  mathematical 
  investigation 
  of 
  

   the 
  effect 
  of 
  such 
  a 
  body 
  on 
  the 
  growth 
  of 
  radium 
  it 
  is 
  

   concluded 
  that 
  it 
  would 
  not, 
  if 
  it 
  existed, 
  appreciably 
  alter 
  

   the 
  production 
  of 
  radium 
  according 
  to 
  the 
  square 
  of 
  the 
  time 
  

   over 
  the 
  period 
  observations 
  have 
  been 
  made, 
  but 
  it 
  would 
  

   vitiate 
  the 
  calculations 
  of 
  the 
  period 
  of 
  the 
  average 
  life 
  of 
  

   the 
  parent 
  of 
  radium 
  according 
  to 
  Rutherford's 
  formula. 
  

   In 
  conclusion, 
  it 
  may 
  be 
  mentioned 
  that 
  a 
  good 
  deal 
  of 
  

   additional 
  evidence 
  bearing 
  directly 
  on 
  this 
  question 
  of 
  the 
  

   existence 
  of 
  new 
  intermediate 
  products 
  has 
  been 
  accumulated 
  

   in 
  an 
  investigation 
  on 
  the 
  rays 
  and 
  product 
  of 
  uranium 
  X, 
  

   w^ith 
  which 
  it 
  is 
  convenient 
  to 
  deal 
  in 
  a 
  separate 
  communi- 
  

   cation. 
  

  

  Physical 
  Chemistry 
  Laboratory, 
  

   University 
  of 
  Glasgow, 
  

   October 
  1909. 
  

  

  XCI. 
  The 
  Roys 
  and 
  Product 
  of 
  Uranium 
  X. 
  

   By 
  FllEDEElCK 
  SODDT, 
  M.A,* 
  

  

  I'^HE 
  preceding 
  paper 
  has 
  dealt 
  with 
  the 
  evidence 
  from 
  

   the 
  rate 
  of 
  production 
  of 
  radium 
  from 
  uranium, 
  which 
  

   suggests 
  the 
  possibility 
  of 
  the 
  existence 
  of 
  at 
  least 
  one 
  new 
  

   intermediate 
  product 
  in 
  the 
  disintegration 
  series. 
  Although 
  

   the 
  experiments 
  are 
  not 
  yet 
  complete, 
  it 
  is 
  advisable 
  also 
  to 
  

   publish 
  a 
  short 
  account 
  of 
  the 
  results 
  obtained 
  in 
  a 
  different 
  

  

  * 
  Preliminary 
  accounts 
  of 
  part 
  of 
  this 
  work 
  appeared 
  in 
  two 
  letters 
  to 
  

   < 
  Nature/ 
  Jan. 
  2Stb, 
  1909, 
  79, 
  p. 
  366, 
  and 
  March 
  11th, 
  1909, 
  80, 
  p. 
  37. 
  

   The 
  paper 
  was 
  communicated 
  to 
  the 
  Physical 
  Society 
  of 
  London 
  on 
  

   Oct. 
  i?2iid, 
  1909. 
  

  

  