﻿tli^ouali 
  the 
  Gases 
  HCl, 
  HBr, 
  and 
  HI. 
  477 
  

  

  The 
  observatioDS 
  are 
  represented 
  in 
  figs. 
  11 
  and 
  12 
  (PI. 
  

   XIY.j. 
  Tiie 
  curves 
  are 
  determined 
  from 
  equation 
  (Ij, 
  and 
  

   we 
  see 
  that 
  they 
  fit 
  in 
  ^yith 
  the 
  observed 
  values 
  to 
  a 
  degree 
  

   that 
  is 
  almost 
  astonishing 
  when 
  the 
  character 
  of 
  the 
  pheno- 
  

   menon 
  is 
  taken 
  into 
  consideration. 
  

  

  Among 
  the 
  properties 
  of 
  the 
  anode 
  fall 
  expressed 
  in 
  the 
  

   two 
  formiilse 
  we 
  shall 
  notice 
  the 
  following 
  two 
  : 
  

  

  1. 
  By 
  diminution 
  of 
  -pressure 
  the 
  anode 
  fall 
  approaches 
  a 
  

   minimum 
  value 
  (Ao) 
  independent 
  of 
  current. 
  

  

  2. 
  For 
  somewhat 
  large 
  currents 
  (when 
  k 
  is 
  not 
  too 
  small) 
  

   the 
  anode 
  fall 
  will 
  be 
  nearly 
  indepe^uUnt 
  of 
  current 
  and 
  follow 
  

   a 
  linear 
  law 
  with 
  regard 
  to 
  pressure. 
  

  

  Absorption 
  of 
  Gas 
  during 
  the 
  Discharge. 
  

  

  § 
  13. 
  It 
  is 
  a 
  well-known 
  phenomenon 
  that 
  gas 
  is 
  absorbed 
  

   in 
  a 
  vacnum-tube 
  when 
  a 
  discharge 
  is 
  made 
  to 
  pass 
  through 
  

   it. 
  It 
  is 
  a 
  common 
  phenomenon 
  in 
  Rontgen 
  tubes 
  where 
  it 
  

   causes 
  the 
  hardening 
  of 
  the 
  rays 
  with 
  age. 
  Considerable 
  

   quantities 
  can 
  be 
  absorbed 
  in 
  this 
  way 
  : 
  thus 
  J. 
  J. 
  Thomson* 
  

   observed 
  that 
  several 
  cubic 
  cm. 
  of 
  gas 
  at 
  atmospheric 
  

   pressure 
  were 
  absorbed 
  without 
  indication 
  of 
  any 
  diminution 
  

   of 
  the 
  absorbing-power. 
  The 
  absorption 
  has 
  been 
  studied 
  by 
  

   Riecke 
  and 
  Skinner_, 
  and 
  more 
  systematic 
  experiments 
  made 
  

   by 
  Willows 
  t. 
  

  

  In 
  the 
  course 
  of 
  my 
  experiments 
  I 
  have 
  had 
  the 
  oppor- 
  

   tunity 
  of 
  examining 
  the 
  absorption 
  for 
  HCl, 
  HBr, 
  and 
  O2 
  

   under 
  conditions 
  of 
  various 
  pressures 
  and 
  currents, 
  and 
  at 
  

   the 
  same 
  time 
  been 
  able 
  to 
  make 
  comparisons 
  with 
  the 
  distri- 
  

   bution 
  of 
  potentiak 
  In 
  this 
  way 
  I 
  have 
  met 
  with 
  some 
  

   characteristic 
  properties 
  of 
  absorption, 
  which 
  I 
  think 
  will 
  

   throw 
  some 
  light 
  on 
  these 
  phenomena 
  that 
  up 
  to 
  the 
  present 
  

   have 
  been 
  very 
  little 
  understood. 
  

  

  Before 
  describing 
  the 
  observations 
  it 
  is 
  good 
  to 
  make 
  clear 
  

   the 
  following 
  conceptions 
  : 
  — 
  

  

  (1) 
  Velocity 
  of 
  cdjsorption 
  (^) 
  equal 
  to 
  number 
  of 
  cm.^ 
  

  

  absorbed 
  per 
  sec. 
  = 
  _^^ 
  -; 
  (V 
  = 
  volume 
  of 
  tube). 
  For 
  the 
  

   7 
  760 
  dt 
  

  

  tube 
  used 
  /x 
  = 
  0-31^^. 
  

   ^ 
  dt 
  

  

  (2) 
  The 
  quantity 
  (5) 
  absorbed 
  when 
  1 
  coulomb 
  has 
  passed 
  

   1 
  V 
  A;7 
  

  

  throuo;h 
  is 
  equal 
  to 
  ^ 
  -;.r.-r-= 
  t- 
  

  

  * 
  J. 
  J. 
  Thomson, 
  ^Conduction 
  of 
  Electricity 
  throudi 
  Gases/ 
  p. 
  o52. 
  

   i 
  R. 
  S. 
  Willow., 
  Phil. 
  Mag-. 
  [0] 
  i. 
  pp. 
  o03-i]7 
  (1901). 
  

  

  