﻿130 
  Mr. 
  S. 
  Rinoshita 
  on 
  Condensation 
  of 
  

  

  which 
  a 
  certain 
  proportion 
  of 
  the 
  emanations 
  remains 
  un- 
  

   condensed 
  depends 
  largely 
  on 
  the 
  pressure, 
  especially 
  when 
  

   this 
  is 
  low. 
  But 
  the 
  variation 
  becomes 
  less 
  when 
  the 
  

   pressure 
  increases. 
  Thus 
  the 
  temperature, 
  at 
  which 
  50 
  

   per 
  cent, 
  of 
  the 
  actinium 
  emanation 
  remains 
  uncondensed, 
  

   varies 
  from 
  — 
  137 
  0, 
  4 
  C. 
  to 
  — 
  146°*5 
  G. 
  as 
  the 
  pressure 
  varies 
  

   from 
  90 
  to 
  190 
  mm., 
  i. 
  e. 
  9° 
  C. 
  for 
  a 
  difference 
  of 
  100 
  mm. 
  

   in 
  pressure, 
  but 
  only 
  6°*5 
  C. 
  from 
  190 
  mm. 
  to 
  atmospheric 
  

   pressure, 
  i. 
  e. 
  for 
  570 
  mm. 
  difference. 
  The 
  thorium 
  ema- 
  

   nation 
  is 
  similar 
  to 
  the 
  above, 
  but 
  condenses 
  at 
  a 
  temperature 
  

   2 
  or 
  6 
  degrees 
  higher 
  than 
  the 
  actinium 
  emanation 
  at 
  the 
  

   low 
  pressure. 
  The 
  difference 
  is 
  not 
  sensible 
  at 
  atmospheric 
  

   pressure. 
  The 
  variation 
  in 
  the 
  amount 
  of 
  condensation 
  of 
  the 
  

   emanation 
  at 
  different 
  pressures 
  is 
  probably 
  connected 
  with 
  

   the 
  greater 
  rapidity 
  of 
  diffusion 
  of 
  the 
  emanation 
  at 
  low 
  

   pressures. 
  

  

  It 
  remains 
  to 
  compare 
  the 
  number 
  of 
  particles 
  of 
  the 
  

   thorium 
  and 
  actinium 
  emanations 
  which 
  entered 
  the 
  spiral 
  in 
  

   the 
  experiments 
  described 
  above. 
  Let 
  N 
  and 
  W 
  be 
  the 
  

   respective 
  numbers 
  which 
  are 
  present 
  in 
  the 
  spiral 
  at 
  the 
  end 
  

   of 
  the 
  time 
  during 
  which 
  each 
  is 
  left 
  in 
  it, 
  when 
  neither 
  

   condenses. 
  Then, 
  assuming 
  that 
  the 
  cc 
  particles 
  from 
  both 
  

   emanations 
  are 
  similar, 
  and 
  possess 
  the 
  same 
  ionizing 
  power 
  

   upon 
  the 
  gas 
  under 
  the 
  same 
  conditions, 
  we 
  have 
  from 
  the 
  

   equation 
  obtained 
  before 
  

  

  N 
  I 
  T 
  *■' 
  s 
  T 
  — 
  s 
  'l—e~ 
  

  

  ■\'T< 
  

  

  for 
  given 
  pressures, 
  where 
  F, 
  X', 
  and 
  s' 
  are 
  values 
  for 
  the 
  

  

  actinium 
  emanation. 
  By 
  substitution 
  of 
  the 
  experimental 
  

  

  W 
  . 
  

   values 
  in 
  this 
  equation 
  ^ 
  is 
  found 
  to 
  be 
  nearly 
  ^. 
  But 
  since 
  

  

  the 
  rate 
  of 
  decay 
  is 
  different 
  for 
  the 
  two 
  emanations, 
  the 
  

  

  number 
  of 
  particles 
  of 
  actinium 
  emanation, 
  on 
  entry 
  into 
  the 
  

  

  1 
  V 
  

   spiral, 
  must 
  have 
  been 
  ^ 
  . 
  —-, 
  or 
  about 
  7 
  times 
  more 
  numerous 
  

  

  than 
  those 
  of 
  the 
  thorium 
  emanation. 
  Still, 
  these 
  numbers 
  

   are 
  of 
  the 
  same 
  order 
  of 
  magnitude, 
  and 
  the 
  experiments 
  

   were 
  thus 
  made 
  as 
  nearly 
  as 
  possible 
  under 
  identical 
  

   conditions. 
  

  

  When 
  this 
  work 
  was 
  finished 
  a 
  paper 
  was 
  published 
  in 
  

   Le 
  Radium, 
  by 
  Henriot*, 
  who 
  applied 
  the 
  method 
  used 
  by 
  

   Goldstein 
  to 
  find 
  the 
  temperature 
  of 
  condensation 
  of 
  the 
  

  

  * 
  Le 
  Radium, 
  torn. 
  v. 
  No. 
  2. 
  p. 
  11 
  (1908). 
  

  

  