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  VI. 
  The 
  Behaviour 
  of 
  the 
  Phosphorus 
  Emanation 
  in 
  

   Spherical 
  Condensers*. 
  — 
  V. 
  By 
  C. 
  BARUSf. 
  

  

  1. 
  TN 
  the 
  preceding 
  papers 
  it 
  was 
  assumed 
  that 
  the 
  con- 
  

   X 
  ditions 
  could 
  be 
  so 
  chosen 
  (swift 
  air-currents, 
  highly 
  

   active 
  ionizer, 
  &c.) 
  that 
  the 
  decay 
  of 
  the 
  ionization 
  might 
  be 
  

   temporarily 
  disregarded. 
  Such 
  an 
  assumption 
  is 
  naturally 
  

   precarious, 
  and 
  the 
  following 
  series 
  of 
  experiments 
  are 
  planned 
  

   with 
  particular 
  reference 
  to 
  the 
  factor 
  ignored. 
  Accordingly 
  

   a 
  closed 
  spherical 
  condenser 
  was 
  installed 
  with 
  its 
  outer 
  

   surface 
  put 
  to 
  earth 
  and 
  its 
  inner 
  (concentric) 
  surface, 
  always 
  

   very 
  small, 
  in 
  contact 
  with 
  the 
  charged 
  electrometer. 
  The 
  

   intervening 
  space 
  was 
  suitably 
  ionized 
  by 
  a 
  small 
  piece 
  of 
  

   phosphorus, 
  about 
  as 
  large 
  as 
  a 
  pea, 
  suspended 
  at 
  the 
  centre 
  

   From 
  such 
  a 
  condenser 
  no 
  ions 
  can 
  escape 
  ; 
  it 
  therefore 
  

   offers 
  greater 
  theoretical 
  simplicity 
  than 
  the 
  plate-condenser, 
  

   as 
  discussed 
  in 
  an 
  earlier 
  paper, 
  while 
  the 
  two 
  discriminating 
  

   variables, 
  radius 
  and 
  voltage, 
  may 
  be 
  changed 
  at 
  will. 
  Prac- 
  

   tically, 
  however, 
  the 
  experiments 
  are 
  very 
  difficult, 
  not 
  only 
  

   because 
  of 
  the 
  baffling 
  irregularity 
  of 
  the 
  ionizer, 
  but 
  because 
  

   it 
  is 
  not 
  easy 
  to 
  lead 
  a 
  charge 
  to 
  or 
  from 
  the 
  centre, 
  without 
  

   conduction. 
  

  

  As 
  a 
  whole, 
  I 
  think, 
  the 
  results 
  may 
  be 
  interpreted 
  as 
  

   showing 
  that 
  decay 
  due 
  to 
  the 
  mutual 
  destruction 
  of 
  ions 
  is 
  

   not 
  in 
  direct 
  evidence, 
  and 
  may 
  be 
  considered 
  negligible 
  in 
  

   investigations 
  of 
  the 
  present 
  order 
  of 
  precision. 
  The 
  enclosed 
  

   air 
  at 
  a 
  distance 
  from 
  the 
  phosphorus 
  rather 
  behaves 
  as 
  though 
  

   it 
  contained 
  more 
  ions 
  than 
  reach 
  it 
  from 
  the 
  source. 
  

  

  2. 
  A 
  series 
  of 
  Konig's 
  resonators 
  seemed 
  very 
  suitable 
  for 
  

   the 
  present 
  purposes, 
  since 
  they 
  were 
  at 
  hand 
  in 
  a 
  large 
  

   range 
  of 
  diameters, 
  and 
  fig. 
  1 
  shows 
  the 
  original 
  adjustment. 
  

   R 
  is 
  the 
  brass 
  resonator 
  ; 
  B 
  the 
  curl 
  of 
  wire 
  making 
  the 
  

   inner 
  surface 
  of 
  the 
  condenser, 
  and 
  supporting 
  the 
  piece 
  of 
  

   phosphorus 
  P 
  ; 
  C 
  is 
  an 
  insulating 
  glass 
  tube 
  30 
  centims. 
  long, 
  

   through 
  which 
  the 
  charge 
  is 
  conveyed 
  by 
  the 
  wire 
  ab, 
  to 
  be 
  dis- 
  

   sipated 
  in 
  the 
  condenser. 
  The 
  tube 
  C 
  is 
  grasped 
  by 
  the 
  hard- 
  

   rubber 
  sheath 
  F, 
  fig. 
  2. 
  B 
  is 
  thus 
  in 
  contact 
  with 
  the 
  electro- 
  

   meter, 
  and 
  the 
  capacity 
  of 
  the 
  latter 
  (about 
  60 
  cm.) 
  is 
  always 
  

   large 
  as 
  compared 
  with 
  the 
  condenser 
  (negligible 
  here 
  and 
  

   less 
  than 
  1 
  cm. 
  in 
  the 
  experiments 
  below). 
  I) 
  is 
  a 
  perforated 
  

   copper 
  plate 
  closing 
  the 
  condenser 
  and 
  putting 
  it 
  to 
  earth 
  

   at 
  E. 
  

  

  3. 
  The 
  early 
  experiments 
  made 
  with 
  this 
  apparatus 
  (Re- 
  

   sonator, 
  K6; 
  2R 
  = 
  8 
  # 
  6cm.) 
  seemed 
  to 
  indicate 
  a 
  linear 
  

  

  * 
  Cf. 
  Am. 
  Journ. 
  Sci. 
  [4] 
  xi. 
  p. 
  310 
  (1901). 
  

  

  t 
  Communicated 
  by 
  the 
  Author. 
  — 
  For 
  previous 
  communications, 
  see 
  

   Phil. 
  Mag. 
  [6] 
  ii. 
  pp. 
  477-488 
  and 
  references 
  there 
  given. 
  

  

  