﻿Alpha 
  Rays 
  by 
  Metals 
  and 
  Gases. 
  615 
  

  

  the 
  form 
  it 
  would 
  take 
  were 
  it 
  possible 
  to 
  move 
  the 
  polonium 
  

   entirely 
  up 
  to 
  the 
  ionization-chamber. 
  At 
  all 
  events 
  these 
  

   assumed 
  portions 
  of 
  the 
  curves 
  can 
  differ 
  but 
  little 
  from 
  what 
  

   the 
  actual 
  curves 
  would 
  be. 
  

  

  Fio-. 
  2. 
  

  

  The 
  ordicates 
  of 
  the 
  curves 
  are 
  the 
  distances 
  in 
  centimetres 
  of 
  the 
  

   polonium 
  from 
  the 
  ionization-chamber. 
  The 
  abscissas 
  are 
  the 
  

   deflexions 
  in 
  centimetres 
  of 
  the 
  electrometer-needle 
  per 
  second. 
  

   Curve 
  I. 
  was 
  obtained 
  in 
  air 
  at 
  a 
  reduced 
  pressure 
  of 
  about 
  

   17 
  centimetres 
  of 
  mercury. 
  Curve 
  II. 
  was 
  obtained 
  in 
  hydrogen 
  at 
  

   normal 
  pressure. 
  

  

  It 
  is 
  to 
  be 
  observed 
  that 
  the 
  two 
  curves 
  in 
  fig. 
  2 
  present 
  

   slight 
  differences 
  in 
  form. 
  'The 
  probable 
  interpretation 
  of 
  

   these 
  differences 
  will 
  now 
  be 
  considered. 
  Any 
  given 
  abscissa 
  

  

  