﻿290 
  

  

  The 
  Genesis 
  of 
  Ions 
  oy 
  Collision. 
  

  

  A 
  corresponding 
  provisional 
  table 
  of 
  sparking 
  potential 
  is 
  

   also 
  given. 
  

  

  Table 
  XVI. 
  

  

  pxa. 
  

  

  V 
  for 
  pure 
  helium. 
  

  

  V 
  for 
  impure 
  helium. 
  

  

  2-8 
  

  

  209 
  

  

  234 
  

  

  3-5 
  

  

  203 
  

  

  231 
  

  

  4 
  

  

  205 
  

  

  231 
  

  

  8 
  

  

  226 
  

  

  268 
  

  

  12 
  

  

  274 
  

  

  

  16 
  

  

  307 
  

  

  

  28 
  

  

  358 
  

  

  

  Fig. 
  7. 
  — 
  Pure 
  Helium. 
  

  

  

  

  

  

  

  

  x-o. 
  

  

  

  

  

  

  

  

  

  / 
  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  V 
  

  

  

  

  

  />xct 
  

  

  

  The 
  experiments 
  on 
  helium, 
  particularly 
  at 
  high 
  pressures, 
  

   were 
  rendered 
  more 
  difficult 
  by 
  an 
  effect 
  analogous 
  to 
  that 
  

   observed 
  by 
  Prof. 
  Townsend 
  and 
  Mr. 
  Hurst 
  in 
  air 
  and 
  

   hydrogen, 
  though 
  it 
  was 
  much 
  greater. 
  The 
  elucidation 
  o£ 
  

   this 
  effect 
  will 
  shortly 
  be 
  attempted, 
  as 
  we 
  hope 
  to 
  make 
  

   further 
  experiments 
  when 
  a 
  continuous 
  supply 
  of 
  liquid 
  air 
  

   will 
  be 
  at 
  our 
  disposal. 
  

  

  In 
  conclusion, 
  we 
  wish 
  to 
  express 
  our 
  best 
  thanks 
  to 
  

   Prof. 
  Townsend, 
  in 
  whose 
  laboratory 
  the 
  research 
  was 
  con- 
  

   ducted, 
  for 
  the 
  facilities 
  he 
  has 
  been 
  ever 
  ready 
  to 
  afford, 
  

   and 
  for 
  the 
  valuable 
  encouragement 
  and 
  advice 
  he 
  has 
  given 
  

   us 
  during 
  the 
  work. 
  

  

  