﻿Scattering 
  of 
  x 
  Particles 
  by 
  Gases. 
  

  

  707 
  

  

  the 
  course 
  of 
  these 
  experiments, 
  and 
  the 
  scattering 
  of 
  each 
  

   gas 
  was 
  compared 
  with 
  air 
  as 
  a 
  standard. 
  The 
  scattering- 
  

   curve 
  for 
  air, 
  which 
  was 
  repeated 
  before 
  and 
  after 
  each 
  

   experiment,' 
  was 
  found 
  to 
  be 
  unchanged 
  throughout 
  the 
  in- 
  

   vestigation. 
  The 
  logarithmic 
  curves 
  for 
  the 
  different 
  gases 
  

   are 
  shown 
  in 
  fig. 
  3. 
  The 
  pressures 
  of 
  gas 
  are 
  plotted 
  as 
  

  

  Pressure 
  in 
  cms. 
  

   io 
  

  

  2 
  

  

  Fig. 
  3. 
  

  

  (UPPER 
  SCALE 
  APPLIES 
  ONLY 
  TO 
  7/L£ 
  CL/ft^S 
  FOPTME: 
  

   CASES 
  HELIUM 
  mo 
  L/YOROGEN.) 
  

   10 
  30 
  40 
  50 
  60 
  

   4 
  _6 
  8 
  10 
  12 
  

  

  abscissse, 
  and 
  the 
  logarithms 
  of 
  the 
  intensity 
  of 
  the 
  unscattered 
  

   radiation 
  passing 
  between 
  the 
  plates 
  as 
  ordinates. 
  

  

  A 
  few 
  details 
  of 
  the 
  method 
  of 
  preparation 
  and 
  purification 
  

   of 
  the 
  gases 
  are 
  given. 
  

  

  Hydrogen. 
  This 
  was 
  prepared 
  electrolytically 
  and 
  dried 
  

   carefully. 
  It 
  contained 
  about 
  1 
  per 
  cent, 
  of 
  impurity, 
  

   chiefly 
  oxygen. 
  A 
  correction 
  was 
  made 
  for 
  this 
  in 
  

   the 
  curve 
  of 
  fig. 
  3, 
  which 
  is 
  the 
  mean 
  of 
  several 
  

   experiments. 
  

  

  Helium. 
  The 
  helium 
  was 
  purified 
  by 
  passing 
  over 
  charcoal 
  

   immersed 
  in 
  liquid 
  air. 
  This 
  removed 
  all 
  traces 
  of 
  

   air 
  and 
  other 
  impurities, 
  except 
  possibly 
  the 
  last 
  traces 
  

   of 
  hydrogen. 
  

  

  