﻿898 
  Prof. 
  0. 
  W. 
  Richardson 
  on 
  the 
  Kinetic 
  

  

  magnitude 
  of 
  this 
  ratio 
  ; 
  and 
  the 
  only 
  method 
  of 
  measure- 
  

   ment 
  which 
  makes 
  use 
  of 
  it 
  in 
  the 
  sequel 
  is 
  vitiated 
  by 
  a 
  far 
  

   greater 
  source 
  of 
  uncertainty 
  arising 
  from 
  the 
  geometrical 
  

   construction 
  of 
  the 
  apparatus 
  employed. 
  So 
  far 
  as 
  the 
  

   present 
  observations 
  go, 
  therefore, 
  the 
  absence 
  of 
  thi« 
  

   particular 
  piece 
  of 
  information 
  is 
  not 
  a 
  matter 
  of 
  great 
  

   moment. 
  

  

  With 
  the 
  positive 
  ionization 
  consistent 
  results 
  were 
  obtained 
  

   throughout 
  the 
  range 
  of 
  potential-difference 
  from 
  40 
  to 
  360 
  

   volts, 
  out 
  this 
  was 
  not 
  the 
  case 
  with 
  the 
  negative 
  ionization. 
  

   Whatever 
  the 
  distribution 
  of 
  sideways 
  velocity 
  may 
  be, 
  ir, 
  is 
  

   clear 
  that 
  the 
  height 
  i 
  of 
  the 
  central 
  ordinate 
  in 
  curves 
  like 
  

   that 
  in 
  tig. 
  2 
  will 
  be 
  greater 
  the 
  greater 
  the 
  applied 
  potential- 
  

   difference 
  ; 
  since 
  with 
  greater 
  potential-differences 
  the 
  ions 
  

   have 
  Less 
  opportunity 
  to 
  spread 
  out 
  sideways. 
  In 
  the 
  case 
  

   of 
  the 
  positive 
  ionization 
  this 
  conclusion 
  was 
  horn 
  4 
  out, 
  by 
  

   the 
  experiments. 
  It 
  was 
  found 
  thai 
  with 
  ions 
  of 
  the 
  same 
  

   valency 
  I 
  ne 
  constant) 
  and 
  for 
  constant 
  values 
  of 
  f. 
  the 
  width 
  

   of 
  the 
  slit, 
  0. 
  the 
  absolute 
  temperature, 
  and 
  z, 
  the 
  distance 
  

   between 
  the 
  plates, 
  the 
  relation 
  ij 
  s/\ 
  = 
  constant, 
  required 
  

   by 
  equation 
  (6), 
  was 
  always 
  fulfilled. 
  Experiments 
  made 
  to 
  

   tesi 
  this 
  point 
  gave 
  the 
  following 
  numbers* 
  WithV-=78 
  

   volts 
  two 
  curves 
  under 
  identical 
  conditions 
  gave 
  for 
  i 
  Q 
  

   the 
  height 
  of 
  the 
  central 
  ordinate 
  the 
  same 
  value 
  2*85 
  

   in 
  arbitrary 
  units. 
  The 
  mean 
  is 
  therefore 
  2 
  85 
  and 
  the 
  

   value 
  of 
  ?' 
  /- 
  v 
  /V 
  = 
  , 
  322. 
  The 
  potential 
  was 
  then 
  changed 
  to 
  

   324 
  volts, 
  the 
  other 
  conditions 
  remaining 
  the 
  same 
  ; 
  two 
  

   determinations 
  of 
  /„ 
  gave 
  5*35 
  and 
  5*90 
  in 
  the 
  same 
  units. 
  

   The 
  mean 
  is 
  thus 
  5*63 
  and 
  the 
  value 
  of 
  /,, 
  \/V=- 
  "ol2. 
  The 
  

   two 
  values 
  of 
  this 
  ratio 
  are 
  constant 
  within 
  the 
  limits 
  of 
  

   experimental 
  error, 
  in 
  agreement 
  with 
  the 
  theory. 
  

  

  With 
  the 
  negative 
  ionization 
  the 
  value 
  of 
  i 
  ) 
  increased 
  with 
  

   the 
  applied 
  potential-difference 
  to 
  a 
  little 
  beyond 
  40 
  volts 
  

   when 
  it 
  reached 
  a 
  maximum 
  ; 
  it 
  then 
  diminished 
  in 
  a 
  very 
  

   marked 
  way 
  as 
  the 
  potential 
  was 
  increased 
  up 
  to 
  820 
  volts, 
  

   at 
  which 
  point 
  the 
  experiments 
  were 
  1 
  discontinued. 
  Not 
  only 
  

   was 
  this 
  the 
  case, 
  but 
  with 
  voltages 
  greater 
  than 
  .SO 
  the 
  

   central 
  maximum 
  in 
  the 
  i.c 
  curve 
  was 
  replaced 
  by 
  a 
  central 
  

   minimum 
  with 
  a 
  maximum 
  on 
  each 
  side 
  of 
  it. 
  The 
  cause 
  of 
  

   this 
  exceptional 
  behaviour 
  of 
  the 
  negative 
  ions 
  is 
  not 
  quite 
  

   certain. 
  It 
  may 
  be 
  that 
  a 
  large 
  number 
  of 
  secondary 
  negative 
  

   ions 
  are 
  emitted 
  by 
  the 
  electrode 
  when 
  it 
  is 
  struck 
  by 
  the 
  

   primary 
  ions, 
  and 
  that 
  some 
  of 
  these 
  escape 
  out 
  of 
  the 
  box. 
  

   Reflexion 
  of 
  the 
  primary 
  ions 
  at 
  the 
  electrode 
  would 
  act 
  in 
  

   the 
  same 
  way. 
  The 
  fact 
  that 
  the 
  abnormal 
  behaviour 
  is 
  

   more 
  marked 
  the 
  higher 
  the 
  potential-difference 
  is 
  in 
  favour 
  

  

  