﻿with 
  the 
  Radium 
  Emanation 
  . 
  

  

  311 
  

  

  gases 
  and 
  emanation 
  had 
  been 
  removed 
  by 
  the 
  pump 
  * 
  a 
  I 
  hope 
  

   in 
  a 
  later 
  paper 
  to 
  give 
  a 
  more 
  detailed 
  account 
  of 
  these 
  and 
  

   other 
  experiments 
  to 
  determine 
  the 
  spectrum 
  of 
  the 
  radium 
  

   emanation. 
  In 
  these 
  investigations 
  the 
  spectrum 
  has 
  been 
  

   obtained 
  incidentally 
  in 
  the 
  course 
  of 
  testing 
  the 
  purity 
  of 
  the 
  

   emanation 
  in 
  the 
  capillary. 
  

  

  Summary 
  of 
  Results. 
  

  

  For 
  convenience, 
  the 
  results 
  o£ 
  experiments 
  II. 
  to 
  V. 
  on 
  

   the 
  volume 
  of 
  the 
  emanation 
  are 
  collected 
  below 
  : 
  — 
  

  

  Experiment. 
  

  

  Initial 
  volume 
  of 
  

  

  emanation 
  per 
  

  

  gram 
  of 
  radium. 
  

  

  Final 
  volume 
  of 
  

  

  emanation 
  per 
  

  

  gram 
  of 
  radium. 
  

  

  II 
  

  

  Ill 
  

  

  IV 
  

  

  V 
  

  

  1-32 
  c.mm. 
  

   0-80 
  „ 
  

   0-97 
  „ 
  

   1-05 
  ,, 
  

  

  59 
  c.mm. 
  

  

  0-66 
  „ 
  

   0-58 
  „ 
  

  

  The 
  volumes 
  here 
  given 
  are 
  at 
  normal 
  pressure 
  and 
  room- 
  

   temperature 
  (about 
  16° 
  C). 
  If 
  corrected 
  to 
  standard 
  tempe- 
  

   rature, 
  the 
  volumes 
  will 
  be 
  about 
  5 
  per 
  cent, 
  smaller. 
  A 
  

   small 
  undetermined 
  correction 
  should 
  also 
  be 
  applied 
  for 
  the 
  

   heating 
  effect 
  of 
  the 
  emanation. 
  We 
  have 
  already 
  seen 
  that 
  

   the 
  calculated 
  volume 
  at 
  normal 
  pressure 
  and 
  temperature 
  is 
  

   0'57 
  c.mm. 
  

  

  From 
  the 
  above 
  table 
  it 
  is 
  seen, 
  that 
  the 
  smallest 
  initial 
  

   volume 
  of 
  the 
  emanation 
  observed 
  is 
  0*80 
  c.mm. 
  per 
  gram 
  of 
  

   radium, 
  and 
  the 
  smallest 
  volume 
  after 
  contraction 
  0*58 
  c.mm. 
  

   The 
  volume 
  before 
  contraction, 
  observed 
  by 
  Ramsay 
  and 
  

   Cameron, 
  was 
  7*07 
  c.mm. 
  per 
  gram. 
  It 
  was 
  observed 
  that 
  

   the 
  emanation 
  was 
  not 
  appreciably 
  absorbed 
  in 
  the 
  capillary 
  

   during 
  the 
  first 
  few 
  hours, 
  provided 
  a 
  discharge 
  was 
  not 
  

   passed, 
  and 
  was 
  all 
  released 
  on 
  lowering 
  the 
  mercury. 
  For 
  

   these 
  reasons, 
  it 
  seems 
  probable 
  that 
  the 
  volume 
  after 
  con- 
  

   traction 
  is 
  to 
  be 
  taken 
  as 
  the 
  true 
  volume 
  of 
  the 
  emanation 
  

   rather 
  than 
  the 
  volume 
  in 
  the 
  beoinnino-. 
  On 
  this 
  view, 
  

   there 
  is 
  as 
  good 
  an 
  agreement 
  as 
  could 
  be 
  expected 
  from 
  

   the 
  nature 
  of 
  the 
  experiments 
  between 
  the 
  final 
  volumes, 
  

  

  * 
  Later 
  observations 
  have 
  confirmed 
  the 
  correctness 
  of 
  this 
  explana- 
  

   tion. 
  The 
  emanation 
  purified 
  after 
  the 
  manner 
  described 
  was 
  introduced 
  

   in 
  a 
  spectrum-tube 
  with 
  platinum 
  electrodes. 
  No 
  trace 
  of 
  the 
  band 
  

   spectrum 
  of 
  carbon 
  dioxide 
  has 
  been 
  observed 
  in 
  the 
  spectrum 
  produced 
  

   by 
  the 
  discharge. 
  (See 
  accompanying' 
  paper 
  " 
  On 
  the 
  Spectrum 
  of 
  the 
  

   Radium 
  Emanation.") 
  

  

  