﻿Gaseous 
  Ionization 
  and 
  Pressure. 
  

  

  79 
  

  

  Salt. 
  

  

  Temp. 
  

  

  N. 
  

  

  /,-xW. 
  

  

  Observer. 
  

  

  KC1 
  

  

  1 
  

  

  17°-5 
  

   10" 
  

  

  •022 
  

  

  •007 
  

  

  147 
  

  

  1-27 
  

  

  y 
  Schuhmeister. 
  

   i 
  

  

  KS0 
  3 
  

  

  7° 
  

   7° 
  

  

  •031 
  

   '0093 
  

  

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  ] 
  

  

  I 
  Seheffer. 
  

  

  ) 
  

  

  

  10° 
  

  

  •015 
  

  

  •92 
  

  

  Sehuhmeister. 
  

  

  , 
  — 
  

  

  The 
  absence 
  of 
  any 
  trustworthy 
  values 
  for 
  the 
  temperature 
  

   coefficients, 
  and 
  more 
  especially 
  the 
  fact 
  that 
  the 
  concentra- 
  

   tions 
  shown 
  above 
  are 
  so 
  much 
  lower 
  than 
  those 
  employed 
  in 
  

   the 
  present 
  paper, 
  render 
  further 
  comparison 
  difficult. 
  

  

  In 
  conclusion, 
  I 
  should 
  like 
  to 
  offer 
  my 
  thanks 
  to 
  the 
  

   Principal 
  and 
  Council 
  of 
  Birkbeck 
  College 
  for 
  assistance 
  in 
  

   carrying 
  the 
  experiments 
  into 
  effect, 
  and 
  especially 
  to 
  Dr. 
  A. 
  

   Griffiths, 
  who 
  not 
  only 
  suggested 
  the 
  research, 
  but 
  has 
  been 
  

   always 
  ready 
  to 
  assist 
  me 
  when 
  in 
  trouble 
  or 
  difficulty. 
  

  

  LXXY. 
  Gaseous 
  Ionization 
  and 
  Pressure. 
  By 
  T. 
  H. 
  Laby, 
  

   B.A., 
  Emmanuel 
  College, 
  Exhibition 
  of 
  '1851 
  Scholar, 
  Joule 
  

   Student 
  of 
  the 
  Royal 
  Society, 
  and 
  G. 
  W. 
  C. 
  Kaye, 
  B.A. 
  

   {Cantab.), 
  B.Sc. 
  (Bond.), 
  A.R.C.Sc, 
  Trinity 
  College, 
  

   Cambridge 
  *. 
  

  

  [Approved 
  as 
  an 
  additional 
  Thesis, 
  in 
  the 
  case 
  of 
  the 
  latter 
  

   author 
  for 
  the 
  Degree 
  of 
  Doctor 
  of 
  Science 
  in 
  the 
  University 
  of 
  

   London.] 
  

  

  [Plate 
  XXVI.] 
  

  

  WHEN 
  7 
  rays 
  act 
  on 
  a 
  constant 
  volume 
  of 
  a 
  gas, 
  it 
  is 
  to 
  

   be 
  expected 
  that 
  they 
  will 
  produce 
  an 
  amount 
  of 
  

   secondary 
  radiation 
  proportional 
  to 
  the 
  pressure 
  of 
  the 
  o- 
  a 
  s 
  ; 
  

   further, 
  the 
  ionization 
  arising 
  from 
  this 
  secondary 
  radiation 
  

   is 
  also 
  proportional 
  to 
  the 
  gas 
  pressure 
  : 
  thus 
  the 
  ionization 
  

   would 
  be 
  proportional 
  to 
  the 
  square 
  of 
  the 
  pressure. 
  This 
  

   view 
  of 
  the 
  dependence 
  of 
  gaseous 
  ionization 
  on 
  pressure 
  is 
  

   given 
  in 
  more 
  detail 
  later. 
  

  

  Though 
  several 
  experiments 
  have 
  been 
  recorded 
  of 
  the 
  

   variation 
  of 
  gaseous 
  ionization 
  with 
  pressure, 
  they 
  do 
  not 
  

   support 
  the 
  above 
  relation 
  ; 
  none 
  of 
  them, 
  however, 
  was 
  for 
  

  

  * 
  Communicated 
  by 
  Professor 
  J. 
  J. 
  Thomson. 
  

  

  