﻿744 
  Mr. 
  W. 
  T. 
  Kennedy 
  on 
  the 
  Active 
  Deposit 
  

  

  At 
  present 
  there 
  is 
  no 
  experimental 
  evidence 
  either 
  for 
  or 
  

   against 
  the 
  view 
  that 
  the 
  disintegration 
  of 
  uranium 
  X 
  is 
  

   multiple, 
  although 
  such 
  evidence 
  has 
  been 
  sought 
  for 
  in 
  this 
  

   laboratory 
  for 
  some 
  time 
  past. 
  It 
  must 
  be 
  understood 
  that 
  

   this 
  particular 
  case 
  has 
  been 
  taken 
  for 
  purposes 
  of 
  illustration 
  

   only. 
  

  

  Physical 
  Chemistry 
  Laboratory, 
  

  

  University 
  of 
  Glasgow, 
  

  

  Sept. 
  13th, 
  1909. 
  

  

  LXXVII. 
  On 
  tJie 
  Active 
  Deposit 
  from 
  Actinium 
  in 
  Unifc 
  

  

  orm 
  

  

  I 
  

  

  Electric 
  Fields. 
  By 
  W. 
  T. 
  Kennedy, 
  j^.yl.* 
  

   [Plate 
  XXII.] 
  

  

  I. 
  Introduction. 
  

  

  N 
  8i 
  number 
  of 
  experiments 
  which 
  have 
  been 
  carried 
  on 
  

   with 
  the 
  emanations 
  and 
  the 
  emanation 
  products 
  from 
  

   the 
  radioactive 
  substances, 
  it 
  has 
  been 
  shown 
  by 
  Rutherford 
  f 
  

   that 
  with 
  thorium 
  emanation 
  the 
  amount 
  of 
  activity 
  imparted 
  

   to 
  a 
  rod 
  charged 
  negatively 
  was 
  independent 
  of 
  the 
  pressure 
  

   until 
  a 
  pressure 
  of 
  10 
  mm. 
  was 
  reached, 
  and 
  that 
  below 
  this 
  

   pressure 
  it 
  decreased 
  as 
  the 
  pressure 
  in 
  the 
  containing 
  vessel 
  

   was 
  lowered. 
  At 
  1/10 
  mm. 
  pressure 
  it 
  was 
  only 
  a 
  small 
  

   fraction 
  of 
  its 
  maximum 
  amount. 
  Makower 
  % 
  has 
  also 
  ob- 
  

   tained 
  similar 
  effects 
  with 
  the 
  excited 
  activity 
  from 
  radium 
  

   em,anation. 
  Further, 
  Rutherford 
  § 
  experimenting 
  with 
  

   radium 
  emanation, 
  found 
  that 
  at 
  atmospheric 
  pressure 
  the 
  

   greater 
  part 
  of 
  the 
  active 
  deposit 
  went 
  to 
  the 
  cathode, 
  while 
  

   only 
  about 
  5 
  per 
  cent, 
  went 
  to 
  the 
  anode. 
  From 
  these 
  results 
  

   he 
  has 
  drawn 
  the 
  conclusion 
  that 
  w^hile 
  most 
  of 
  the 
  active 
  

   deposit 
  particles 
  of 
  radium 
  are 
  positively 
  charged, 
  some 
  at 
  

   least 
  must 
  carry 
  a 
  negative 
  charge, 
  inasmuch 
  as 
  they 
  are 
  

   drawn 
  to 
  the 
  anode 
  in 
  electric 
  fields. 
  

  

  More 
  recently 
  Russ 
  || 
  showed 
  that 
  when 
  positively 
  and 
  

   negatively 
  charged 
  electrodes 
  were 
  placed 
  in 
  a 
  vessel 
  containing 
  

   either 
  air,*^ 
  sulphur 
  dioxide, 
  or 
  hydrogen 
  charged 
  wdth 
  the 
  ema- 
  

   nation 
  from 
  radium, 
  the 
  relative 
  amounts 
  of 
  the 
  active 
  deposits 
  

   obtained 
  on 
  the 
  two 
  electrodes 
  varied 
  with 
  the 
  pressure 
  at 
  

   which 
  the 
  exposures 
  were 
  m.ade. 
  With 
  all 
  three 
  gases 
  the 
  

  

  * 
  Communicated 
  by 
  Professor 
  J. 
  C. 
  McLennan, 
  and 
  read 
  before 
  the 
  

   Royal 
  Society 
  of 
  Canada 
  on 
  May 
  26, 
  1909. 
  

   t 
  Rutherford, 
  Phil. 
  Mag-. 
  Feb. 
  1900. 
  

   + 
  Makower, 
  Phil. 
  Mag. 
  Nov. 
  1905. 
  

   § 
  Rutherford, 
  Phil. 
  Mao-. 
  Jau. 
  ]903. 
  

   II 
  Russ, 
  Phil. 
  Mag. 
  May 
  1908. 
  

  

  