﻿Earth's 
  Penetrating 
  Radiation 
  with 
  Wulf 
  Electrometer. 
  743 
  

  

  or 
  . 
  _ 
  VQ 
  1 
  -V 
  1 
  Q 
  

  

  V-V 
  L 
  ' 
  

  

  = 
  Qi- 
  vQ 
  

   y 
  

  

  if 
  — 
  ^ 
  is 
  a 
  small 
  quantity. 
  

  

  The 
  charge 
  en 
  the 
  ions 
  generated 
  per 
  cubic 
  centimetre 
  

   per 
  sec. 
  is 
  then 
  given 
  by 
  

  

  B 
  = 
  

  

  Q-Qi 
  

  

  v-vr 
  

  

  Let 
  now 
  Av 
  be 
  the 
  loss 
  in 
  voltage 
  per 
  hour 
  with 
  the 
  tube 
  

  

  up, 
  and 
  At 
  1 
  ! 
  with 
  it 
  down. 
  

  

  Then 
  if 
  C 
  is 
  the 
  capacity 
  of 
  the 
  system 
  

  

  CAr 
  . 
  l-04Av 
  

  

  300x3600' 
  300x3600 
  

  

  in 
  the 
  present 
  case, 
  and 
  

  

  ' 
  1-04A1?! 
  

  

  300x3600* 
  

  

  From 
  this 
  it 
  follows 
  that 
  B 
  is 
  given 
  by 
  

  

  1-04 
  (Ai?-Ai? 
  1 
  ) 
  

   300 
  x 
  3600(V-Vi)" 
  

  

  Finally, 
  the 
  number 
  of 
  ions 
  generated 
  per 
  sec. 
  per 
  c.c. 
  if 
  

   saturation 
  voltages 
  are 
  used 
  is 
  given 
  by 
  N= 
  — 
  , 
  where 
  e 
  is 
  

   the 
  charge 
  on 
  an 
  ion 
  in 
  electrostatic 
  units, 
  i. 
  e. 
  

   N= 
  _ 
  l-04(Atf-A 
  Vl 
  ) 
  

  

  300x3600(V-V 
  1 
  >' 
  

  

  or, 
  if 
  V 
  be 
  taken 
  as 
  202T1 
  c.c, 
  V 
  x 
  as 
  31'5 
  c.c, 
  and 
  

   ^=4-75 
  xlO" 
  10 
  , 
  

  

  N 
  l'04(Ai?-At; 
  1 
  ) 
  

  

  300 
  x 
  3600 
  . 
  (2021-1-31-5) 
  x 
  4*75 
  x 
  ltR>' 
  

   or 
  

  

  N 
  = 
  l-02(At7— 
  Awj), 
  

  

  i. 
  e. 
  the 
  number 
  of 
  ions 
  generated 
  in 
  the 
  receiver 
  per 
  cubic 
  

   centimetre 
  per 
  sec. 
  is 
  equal 
  to 
  1*02 
  times 
  the 
  difference 
  in 
  

   the 
  drops 
  in 
  voltage 
  per 
  hour 
  observed 
  with 
  the 
  tube 
  ss 
  

   up 
  and 
  down. 
  

  

  3D2 
  

  

  