﻿Phosphorus 
  Emanation 
  in 
  Spherical 
  Condenses. 
  i)l 
  

  

  In 
  endeavouring 
  to 
  account 
  for 
  the 
  data 
  obtained 
  it 
  was 
  

   my 
  endeavour 
  to 
  follow 
  the 
  established 
  theory 
  ; 
  but 
  I 
  fear 
  

   that 
  in 
  the 
  explanations 
  given 
  I 
  have 
  little 
  by 
  little 
  made 
  a 
  

   serious 
  departure. 
  If 
  I 
  had 
  obtained 
  but 
  a 
  single 
  coincidence 
  

   the 
  result 
  would 
  not 
  have 
  deserved 
  record 
  ; 
  but 
  after 
  finding 
  

   data 
  of 
  a 
  correct 
  order 
  of 
  values 
  in 
  all 
  the 
  experiments, 
  in 
  

   spite 
  of 
  the 
  variations 
  of 
  method, 
  I 
  have 
  ventured 
  to 
  think 
  

   that 
  more 
  than 
  a 
  coincidence 
  is 
  in 
  question. 
  The 
  theory 
  

   which 
  provisionally 
  underlies 
  the 
  series 
  of 
  papers 
  is 
  sub- 
  

   stantially 
  this 
  : 
  — 
  

  

  (1) 
  From 
  experiments 
  made 
  in 
  the 
  absence 
  of 
  an 
  electrical 
  

   field 
  I 
  inferred 
  that 
  the 
  nucleus 
  has 
  its 
  own 
  specific 
  velocity 
  

   and 
  that 
  this 
  velocity 
  is 
  identical 
  with 
  the 
  mutual 
  velocity 
  of 
  

   the 
  corresponding 
  ions 
  in 
  the 
  unit 
  electrical 
  field 
  (volt/centim.) 
  . 
  

  

  (2) 
  The 
  nucleus 
  produced 
  by 
  phosphorus 
  is 
  larger 
  than 
  

   the 
  air 
  molecule 
  ; 
  and 
  both 
  for 
  this 
  reason 
  and 
  from 
  the 
  fact 
  

   that 
  it 
  receives 
  promiscuous 
  bombardment 
  of 
  molecules 
  simul- 
  

   taneously, 
  its 
  velocity 
  is 
  of 
  the 
  low 
  order 
  stated, 
  being 
  (say) 
  

   less 
  than 
  1/300 
  that 
  of 
  the 
  air 
  molecule. 
  

  

  (3) 
  It 
  is 
  not 
  necessary 
  to 
  assume 
  that 
  the 
  nucleus 
  decays 
  or 
  

   vanishes 
  within 
  the 
  ionized 
  medium 
  ; 
  the 
  evidence 
  is 
  rather 
  

   in 
  favour 
  of 
  a 
  number 
  of 
  nuclei 
  somewhat 
  larger 
  as 
  the 
  

   dilution 
  increases. 
  

  

  (4) 
  Whenever 
  the 
  nucleus 
  comes 
  in 
  contact 
  with 
  a 
  barrier 
  

   (solid 
  or 
  liquid) 
  it 
  is 
  absorbed 
  or 
  broken 
  up. 
  If 
  the 
  nucleus 
  

   is 
  ionized 
  as 
  in 
  the 
  case 
  of 
  the 
  phosphorus 
  emanation, 
  the 
  

   absorption 
  is 
  accompanied 
  with 
  the 
  discharge 
  of 
  an 
  electron. 
  

  

  (5) 
  The 
  observations 
  with 
  plate-condensers, 
  tubular 
  con- 
  

   densers, 
  and 
  spherical 
  condensers 
  are 
  satisfied 
  by 
  supposing 
  

   the 
  nuclear 
  velocity 
  k 
  to 
  be 
  independent 
  of 
  the 
  concentration 
  

   or 
  degree 
  of 
  saturation. 
  

  

  (6) 
  The 
  nuclear 
  velocity 
  is 
  independent 
  of 
  the 
  potential 
  

   gradient. 
  Instead 
  of 
  putting 
  U 
  . 
  V/R 
  for 
  the 
  velocity 
  of 
  the 
  

   ion 
  along 
  the 
  potential 
  gradient 
  V/R, 
  I 
  have 
  considered 
  this 
  

   velocity 
  a 
  constant, 
  independent 
  of 
  V/R 
  ; 
  while 
  the 
  number 
  

   of 
  nuclei 
  capable 
  of 
  discharging 
  the 
  metallic 
  terminal 
  of 
  a 
  

   field 
  varies 
  as 
  V/R. 
  

  

  (7) 
  If 
  for 
  e 
  the 
  charge 
  of 
  a 
  nucleus, 
  J. 
  J. 
  Thomson's 
  

   electron 
  be 
  taken 
  ; 
  if 
  \J 
  = 
  k, 
  then 
  the 
  number 
  of 
  nuclei* 
  in 
  

   the 
  saturated 
  phosphorus 
  emanation 
  agrees 
  with 
  J.J.Thomson's 
  

   value 
  for 
  the 
  number 
  of 
  ions 
  in 
  ionized 
  air. 
  

  

  Brown 
  University, 
  Providence, 
  U.S.A. 
  

  

  * 
  1 
  have 
  since 
  found 
  that 
  the 
  lower 
  values 
  found 
  from 
  tubular 
  

   condensers 
  are 
  referable 
  to 
  the 
  inherent 
  non-saturation. 
  By 
  using 
  an 
  

   excess 
  of 
  freshly 
  cut 
  phosphorus, 
  the 
  number 
  of 
  ions 
  could* 
  be 
  nearly 
  

   doubled, 
  thus 
  putting 
  these 
  results 
  in 
  accord 
  with 
  the 
  correlative 
  data 
  for 
  

   plate- 
  and 
  for 
  spherical 
  condensers. 
  

  

  