﻿H. 
  A. 
  Bumstead 
  — 
  Velocities 
  of 
  Delta 
  Bays. 
  105 
  

  

  observations 
  made 
  in 
  this 
  manner 
  is 
  represented 
  in 
  fig. 
  5. 
  It 
  

   is 
  within 
  this 
  region 
  that 
  all 
  previous 
  measurements 
  of 
  the 
  

   velocities 
  of 
  8-rays 
  have 
  been, 
  so 
  far 
  as 
  I 
  know, 
  confined. 
  

   Most, 
  if 
  not 
  all, 
  of 
  such 
  measurements 
  have 
  been, 
  I 
  believe, 
  to 
  

   a 
  considerable 
  extent 
  vitiated 
  by 
  two 
  circumstances 
  : 
  lack 
  of 
  

   knowledge 
  of 
  the 
  existence 
  of 
  the 
  swifter 
  rays 
  and 
  of 
  the 
  ter- 
  

   tiary 
  rays 
  which 
  they 
  produce; 
  and 
  the 
  fact 
  that 
  the 
  a-rays 
  

   were 
  allowed 
  to 
  pass 
  through 
  the 
  field, 
  thus 
  giving 
  two 
  sources 
  

  

  30 
  35 
  -40 
  AS 
  

  

  NEGATIVE 
  VOLTS 
  ON 
  6AUZC 
  

  

  of 
  S-rays, 
  and 
  of 
  tertiary 
  rays, 
  with 
  much 
  consequent 
  confusion 
  

   of 
  the 
  results. 
  

  

  Among 
  neither 
  the 
  swifter, 
  nor 
  the 
  slower, 
  rays 
  is 
  there 
  any 
  

   approach 
  to 
  the 
  Maxwellian 
  exponential 
  distribution 
  ; 
  if 
  it 
  

   were 
  so, 
  the 
  integrated 
  curves 
  (those 
  of 
  figs. 
  3, 
  4, 
  and 
  5) 
  

   would 
  also 
  be 
  exponential. 
  This 
  is 
  not 
  true 
  in 
  either 
  case 
  ;* 
  

   the 
  diminution 
  in 
  the 
  ordinates 
  is 
  too 
  rapid 
  at 
  the 
  lower 
  

   potentials 
  and 
  too 
  slow 
  at 
  the 
  higher. 
  If 
  we 
  plot 
  V 
  V 
  instead 
  

   of 
  V, 
  thus 
  making 
  the 
  abscissae 
  proportional 
  to 
  velocities 
  

  

  * 
  In 
  the 
  curves 
  of 
  figs. 
  3 
  and 
  4, 
  allowance 
  inust 
  be 
  made 
  for 
  the 
  depression 
  

   of 
  the 
  zero 
  line 
  ; 
  but 
  no 
  reasonable 
  adjustment 
  of 
  this 
  sort 
  will 
  bring 
  the 
  

   curves 
  near 
  to 
  an 
  exponential 
  form. 
  

  

  