﻿330 
  Prof. 
  H. 
  A. 
  Erikson 
  on 
  tJie 
  Recombination 
  of 
  

  

  Q 
  was 
  measured 
  in 
  the 
  ordinary 
  way 
  by 
  obtaining 
  the 
  

   time 
  (T) 
  required 
  for 
  the 
  leaf 
  of 
  the 
  electroscope 
  to 
  move 
  a 
  

   certain 
  number 
  of 
  divisions 
  when 
  the 
  key 
  A 
  was 
  open^ 
  

   1000 
  volts 
  being 
  applied 
  to 
  the 
  outside 
  of 
  the 
  chamber. 
  

   During 
  this 
  measurement 
  the 
  capacity 
  (C) 
  was 
  added 
  to 
  the 
  

   capacity 
  (Oi) 
  of 
  the 
  electrode 
  system. 
  

  

  N 
  was 
  obtained 
  by 
  measuring 
  the 
  total 
  charge 
  in 
  the 
  gas 
  

   when 
  equilibrium 
  had 
  been 
  established. 
  This 
  was 
  accom- 
  

   plished 
  by 
  means 
  of 
  the 
  contacts 
  made 
  by 
  the 
  horizontal 
  

   slide 
  S, 
  which 
  could 
  be 
  released 
  and 
  made 
  to 
  move 
  by 
  

   means 
  of 
  a 
  suspended 
  weight. 
  When 
  the 
  slide 
  was 
  in 
  the 
  

   position 
  shown 
  in 
  fig. 
  1 
  everything 
  was 
  connected 
  to 
  earth. 
  

   When 
  the 
  slide 
  is 
  released 
  contact 
  is 
  made 
  at 
  a 
  opening 
  

   the 
  key 
  B, 
  thus 
  insulating 
  the 
  inner 
  electrode 
  of 
  the 
  

   chamber. 
  A 
  little 
  later 
  the 
  slide 
  makes 
  contact 
  at 
  b, 
  which 
  

   connects 
  the 
  ionization- 
  chamber 
  to 
  a 
  high 
  potential 
  E. 
  

   Considerable 
  difficulty 
  was 
  here 
  experienced 
  in 
  preventing 
  a 
  

   partial 
  loss 
  of 
  the 
  free 
  induced 
  charge 
  through 
  leakage 
  to 
  

   the 
  guard-ring 
  G. 
  It 
  was 
  found, 
  however, 
  that 
  this 
  could 
  

   be 
  overcome 
  in 
  a 
  very 
  satisfactory 
  manner 
  by 
  applying 
  a 
  

   voltage 
  of 
  about 
  |- 
  E 
  to 
  the 
  guard-ring 
  G 
  at 
  the 
  same 
  

   instant 
  that 
  E 
  Avas 
  applied 
  to 
  the 
  chamber, 
  and 
  then 
  

   connecting 
  the 
  guard-ring 
  to 
  earth 
  again 
  at 
  the 
  same 
  time 
  

   that 
  the 
  chamber 
  was 
  earthed. 
  This 
  was 
  accomplished 
  by 
  

   the 
  relay 
  D 
  when 
  the 
  slide 
  made 
  contact 
  at 
  c 
  and 
  broke 
  

   contact 
  at 
  d. 
  At 
  e 
  the 
  slide 
  disconnects 
  the 
  chamber 
  from 
  

   the 
  high 
  potential 
  E 
  and 
  an 
  instant 
  later 
  earths 
  the 
  chamber 
  

   through 
  contact 
  at 
  /. 
  

  

  When 
  the 
  slide 
  makes 
  contact 
  at 
  g 
  the 
  key 
  A 
  is 
  opened, 
  

   thereby 
  insulating 
  the 
  leaf 
  of 
  the 
  electroscope. 
  At 
  h 
  the 
  

   inner 
  electrode 
  is 
  connected 
  to 
  the 
  leaf 
  by 
  closing 
  key 
  B, 
  

   the 
  charge 
  CiVi 
  collected 
  on 
  the 
  electrode 
  causing 
  the 
  

   leaf 
  to 
  deflect. 
  Contact 
  at 
  i 
  opens 
  the 
  key 
  B 
  again 
  and 
  

   insulates 
  the 
  leaf. 
  From 
  the 
  deflexion 
  the 
  potential 
  Vi 
  to 
  

   which 
  the 
  charge 
  has 
  raised 
  the 
  capacity 
  Ci 
  of 
  the 
  electrode 
  

   system 
  is 
  determined. 
  

  

  The 
  collected 
  charge 
  CiYi 
  requires 
  two 
  corrections 
  : 
  

   During 
  the 
  time 
  (t) 
  that 
  E 
  was 
  applied 
  to 
  the 
  chamber, 
  the 
  

   rays 
  produced 
  a 
  quantity 
  Qet 
  which 
  must 
  be 
  subtracted. 
  

   Also 
  during 
  the 
  time 
  {t') 
  from 
  break 
  of 
  contact 
  at 
  e 
  to 
  

   make 
  of 
  contact 
  at 
  i 
  a 
  back-leak 
  took 
  place 
  which 
  must 
  be 
  

   added. 
  The 
  leak 
  per 
  second 
  (L) 
  was 
  readily 
  determined 
  by 
  

   charging 
  the 
  electrode 
  system 
  to 
  a 
  potential 
  a 
  few 
  divisions 
  

   higher 
  and 
  noting 
  the 
  time 
  (Ti) 
  required 
  for 
  the 
  leaf 
  to 
  move 
  

   to 
  a 
  point 
  the 
  same 
  number 
  of 
  divisions 
  lower 
  than 
  the 
  

  

  