﻿Conductivity 
  imparted 
  to 
  Liquid 
  Air 
  by 
  Alpha 
  Rays. 
  877 
  

  

  approximately 
  1*4824. 
  This 
  it 
  will 
  be 
  seen 
  is 
  very 
  close 
  to 
  

   the 
  value 
  found 
  by 
  Dewar 
  and 
  Fleming 
  in 
  their 
  experiments. 
  

  

  In 
  view 
  of 
  this 
  continuity 
  in 
  the 
  dielectric 
  property 
  of 
  

   oxygen 
  in 
  passing 
  through 
  the 
  stage 
  of 
  liquefaction, 
  it 
  was 
  

   thought 
  to 
  be 
  of 
  interest 
  by 
  the 
  writers 
  to 
  see 
  if 
  any 
  indica- 
  

   tion 
  of 
  a 
  similar 
  continuity 
  could 
  be 
  obtained 
  in 
  the 
  ionization 
  

   of 
  air 
  by 
  alpha 
  rays 
  when 
  passing 
  from 
  the 
  gaseous 
  to 
  the 
  

   liquid 
  state. 
  P. 
  Curie 
  *, 
  Jaffe 
  f 
  , 
  Cacilia 
  Bohm-Wendt 
  and 
  

   E. 
  von 
  Schweidler 
  t, 
  and 
  Bialobjeski 
  §, 
  have 
  shown 
  that 
  a 
  

   conductivity 
  can 
  be 
  impressed 
  on 
  certain 
  dielectric 
  liquids 
  by 
  

   gain 
  ma 
  rays, 
  but 
  Greinacher 
  || 
  appears 
  to 
  have 
  been 
  the 
  only 
  

   investigator 
  who 
  has 
  studied 
  the 
  ionization 
  produced 
  in 
  such 
  

   liquids 
  by 
  alpha 
  rays. 
  His 
  experiments 
  were 
  made 
  with 
  

   paraffin 
  oil 
  and 
  petrol 
  ether. 
  

  

  Among 
  other 
  results 
  he 
  found 
  : 
  — 
  

  

  1 
  . 
  That 
  the 
  conductivity 
  so 
  impressed 
  was 
  independent 
  of 
  

  

  the 
  direction 
  of 
  the 
  current, 
  and 
  that 
  therefore 
  the 
  

   mobilities 
  of 
  the 
  positive 
  and 
  negative 
  ions 
  produced 
  

   in 
  these 
  liquids 
  by 
  the 
  alpha 
  rays 
  were 
  practically 
  

   identical. 
  

  

  2. 
  That 
  with 
  petrol 
  ether 
  a 
  saturation-current 
  was 
  obtained 
  

  

  with 
  a 
  field 
  of 
  about 
  400 
  volts 
  per 
  cm., 
  but 
  that 
  in 
  

   the 
  case 
  of 
  petroleum 
  oil 
  complete 
  saturation 
  was 
  not 
  

   obtained 
  even 
  when 
  fields 
  as 
  high 
  as 
  10,000 
  volts 
  

   per 
  cm. 
  were 
  applied. 
  : 
  and 
  

  

  3. 
  That 
  the 
  total 
  ionization 
  produced 
  in 
  air 
  at 
  atmospheric 
  

  

  pressure 
  when 
  the 
  alpha 
  rays 
  from 
  a 
  sample 
  of 
  

   polonium 
  were 
  completely 
  absorbed, 
  was 
  about 
  2000 
  

   times 
  as 
  great 
  as 
  the 
  total 
  ionization 
  produced 
  in 
  

   petrol 
  ether 
  when 
  the 
  radiation 
  from 
  the 
  same 
  polonium 
  

   was 
  completely 
  absorbed 
  by 
  that 
  liquid. 
  

  

  In 
  the 
  following 
  paper 
  an 
  account 
  is 
  given 
  of 
  some 
  

   preliminary 
  experiments 
  made 
  on 
  the 
  ionization 
  of 
  liquid 
  air 
  

   by 
  alpha 
  rays, 
  and 
  from 
  the 
  results 
  which 
  are 
  given 
  below 
  it 
  

   will 
  be 
  seen 
  that 
  the 
  findings 
  of 
  others 
  are 
  confirmed 
  in 
  

   regard 
  to 
  the 
  high 
  insulating 
  power 
  of 
  liquid 
  air. 
  It 
  will 
  be 
  

   shown, 
  too, 
  that 
  the 
  conductivity 
  impressed 
  by 
  alpha 
  rays 
  on 
  

   liquid 
  air 
  is 
  similar 
  in 
  some 
  regards 
  to 
  that 
  obtained 
  by 
  

   Greinacher 
  in 
  his 
  experiments 
  with 
  petroleum 
  and 
  petrol 
  

   ether 
  traversed 
  by 
  alpha 
  rays. 
  

  

  * 
  Curie, 
  C. 
  R. 
  vol. 
  cxxxiv. 
  p. 
  420 
  (1902). 
  

  

  t 
  Jatfe, 
  Ann. 
  d. 
  Phys. 
  vol. 
  xxviii. 
  p. 
  326 
  (1909). 
  

  

  1 
  Bohm-Wendt 
  and 
  Schweidler, 
  Phys. 
  Zeit. 
  vol. 
  x. 
  p. 
  379 
  (1909). 
  

  

  § 
  Bialobjeski, 
  Le 
  Radium, 
  p. 
  293, 
  Aug. 
  1911. 
  

  

  D 
  Greinacher, 
  Phys. 
  Zeit. 
  10 
  Jahr. 
  No. 
  25, 
  p. 
  986. 
  

  

  