﻿616 
  Mr. 
  T. 
  S. 
  Taylor 
  on 
  the 
  Retardation 
  of 
  

  

  of 
  either 
  curve 
  is 
  a 
  measure 
  o£ 
  the 
  ionization 
  produced 
  by 
  

   the 
  particles 
  in 
  the 
  gas 
  in 
  the 
  chamber 
  when 
  the 
  polonium 
  

   was 
  at 
  a 
  distance 
  from 
  the 
  chamber 
  represented 
  by 
  the 
  

   orduiate 
  corresponding 
  to 
  the 
  given 
  abscissa. 
  Consequently, 
  

   the 
  total 
  area 
  enclosed 
  by 
  the 
  two 
  axes 
  o£ 
  reference 
  and 
  

   either 
  curve 
  is 
  proportional 
  to 
  the 
  total 
  ionization 
  produced 
  

   in 
  the 
  gas 
  in 
  which 
  the 
  curve 
  was 
  determined. 
  By 
  mea- 
  

   suring 
  these 
  areas 
  with 
  a 
  planimeter, 
  it 
  was 
  found 
  they 
  were 
  

   equal. 
  This 
  confirms 
  the 
  observations 
  by 
  Bragg 
  * 
  that 
  the 
  

   total 
  ionization 
  produced 
  by 
  the 
  alpha-particle 
  in 
  air 
  is 
  the 
  

   same 
  as 
  that 
  in 
  hydrogen. 
  From 
  the 
  curves 
  of 
  fig. 
  2 
  it 
  is 
  seen 
  

   that 
  when 
  the 
  speed 
  of 
  the 
  alpha-particle 
  is 
  high 
  more 
  ions 
  are 
  

   produced 
  per 
  centimetre 
  of 
  path 
  in 
  air 
  than 
  in 
  hydrogen, 
  but 
  

   when 
  the 
  speed 
  is 
  low 
  more 
  ions 
  are 
  produced 
  per 
  centimetre 
  

   in 
  hydrogen 
  than 
  in 
  air. 
  

  

  Let 
  us 
  suppose 
  that 
  for 
  a 
  given 
  speed 
  of 
  the 
  alpha-particle 
  

   the 
  amount 
  of 
  energy 
  required 
  to 
  produce 
  an 
  ion 
  is 
  the 
  same 
  

   in 
  all 
  substances. 
  Then 
  for 
  air 
  we 
  would 
  have 
  the 
  relation 
  

  

  The 
  corresponding 
  relation 
  in 
  hydrogen 
  is 
  

  

  Dividing 
  the 
  former 
  by 
  the 
  latter, 
  we 
  have 
  

  

  dh''f(V)dW 
  

   which 
  for 
  a 
  given 
  speed 
  V 
  in 
  each 
  gas 
  reduces 
  to 
  

  

  dla 
  _ 
  dEa 
  

  

  dlh 
  dEh 
  

   From 
  this 
  it 
  is 
  seen 
  that 
  for 
  a 
  given 
  speed 
  of 
  the 
  alpha- 
  

   particle 
  the 
  ratio 
  of 
  the 
  rates 
  of 
  the 
  consumption 
  of 
  the 
  energy 
  

   in 
  producing 
  ions 
  in 
  air 
  and 
  hydrogen, 
  is 
  equal 
  to 
  the 
  ratio 
  of 
  

   the 
  rates 
  at 
  which 
  the 
  ionization 
  is 
  produced 
  in 
  the 
  respective 
  

   gases. 
  On 
  the 
  basis 
  of 
  our 
  hypothesis, 
  let 
  us 
  consider 
  the 
  

   ratios 
  of 
  the 
  energies 
  consumed 
  in 
  the 
  4th 
  and 
  13th 
  centi- 
  

   metres 
  (fig. 
  2) 
  of 
  the 
  path 
  of 
  the 
  particle 
  in 
  air 
  and 
  hydrogen. 
  

   This 
  ratio 
  for 
  the 
  4th 
  centimetre 
  of 
  the 
  path 
  is 
  proportional 
  

  

  area 
  C(i 
  43 
  c 
  . 
  , 
  , 
  < 
  • 
  i 
  . 
  i 
  i 
  

  

  to 
  TTTr-, 
  since 
  the 
  areas 
  are 
  proportional 
  to 
  the 
  

  

  area 
  ac> 
  4o 
  a 
  

  

  ionizations 
  produced 
  in 
  the 
  gases. 
  The 
  corresponding 
  ratio 
  

  

  for 
  the 
  13th 
  centimetre 
  is 
  equal 
  to 
  ''7^ 
  io\o' 
  • 
  The 
  

  

  ^ 
  area 
  g, 
  A, 
  lo, 
  IZ, 
  g 
  

  

  former 
  ratio 
  is 
  seen 
  from 
  the 
  figure 
  to 
  be 
  greater 
  than 
  the 
  

   * 
  Phil. 
  Mag-. 
  March 
  1907; 
  p. 
  333. 
  

  

  