﻿3.10 
  Prof. 
  E. 
  Rutherford 
  : 
  Experiments 
  

  

  the 
  gaseous 
  state. 
  The 
  emanation 
  remained 
  fast 
  to 
  the 
  walls 
  

   for 
  two 
  days, 
  and 
  was 
  only 
  removed 
  finally 
  by 
  a 
  vigorous 
  

   heating 
  of 
  the 
  tube. 
  It 
  appears 
  that 
  the 
  emanation 
  must 
  

   have 
  been 
  driven 
  into 
  the 
  walls 
  of 
  the 
  tube 
  or 
  occluded 
  in 
  it 
  

   under 
  some 
  condition 
  due 
  to 
  the 
  passage 
  of 
  the 
  discharge. 
  

  

  Experiment 
  IV, 
  — 
  In 
  this 
  case 
  the 
  emanation, 
  after 
  the 
  

   initial 
  purification, 
  was 
  left 
  five 
  hours 
  over 
  caustic 
  potash. 
  

   After 
  introduction 
  the 
  initial 
  volume 
  was 
  '126 
  c.mm. 
  The 
  

   volume 
  remained 
  nearly 
  stationary 
  for 
  20 
  minutes 
  and 
  then 
  

   slowly 
  diminished, 
  reaching 
  a 
  value 
  of 
  *076 
  c.mm. 
  after 
  

   17 
  hours. 
  The 
  amount 
  of 
  radium 
  emanation 
  initially 
  present 
  

   was 
  130 
  mgs. 
  radium. 
  The 
  initial 
  volume 
  of 
  emanation 
  thus 
  

   corresponded 
  to 
  0*97 
  c.mm. 
  per 
  gram 
  of 
  radium, 
  and 
  the 
  

   lowest 
  volume, 
  allowing 
  for 
  the 
  decay 
  of 
  the 
  emanation 
  in 
  

   the 
  interim, 
  corresponded 
  to 
  0'66 
  c.mm. 
  per 
  gram. 
  

  

  Experiment 
  V. 
  — 
  The 
  emanation 
  used 
  in 
  experiment 
  IV. 
  

   was 
  again 
  condensed 
  in 
  the 
  U-tubeand 
  then 
  left 
  for 
  24 
  hours 
  

   in 
  the 
  presence 
  of 
  caustic 
  potash. 
  The 
  emanation 
  after 
  

   further 
  treatment 
  was 
  admitted 
  into 
  the 
  capillary. 
  The 
  

   initial 
  volume 
  was 
  '083 
  c.mm. 
  As 
  in 
  the 
  case 
  of 
  experi- 
  

   ment 
  IV., 
  the 
  volume 
  remained 
  nearly 
  stationary 
  for 
  20 
  

   minutes 
  and 
  then 
  slowly 
  decreased. 
  The 
  volume 
  after 
  

   4 
  hours 
  was 
  *046 
  c.mm. 
  The 
  amount 
  of 
  radium 
  emanation 
  

   in 
  the 
  tube 
  was 
  equal 
  to 
  79 
  mgs. 
  radium. 
  Consequently 
  the 
  

   initial 
  volume 
  of 
  the 
  emanation 
  per 
  gram 
  was 
  1*05 
  c.mm., 
  

   and 
  the 
  volume 
  after 
  4 
  hours 
  0'58 
  c.mm. 
  The 
  spectrum 
  of 
  the 
  

   gases 
  in 
  the 
  capillary 
  was 
  then 
  examined. 
  As 
  before 
  the 
  carbon 
  

   dioxide 
  spectrum 
  was 
  seen 
  together 
  with 
  a 
  number 
  of 
  new 
  lines 
  

   due 
  to 
  the 
  emanation, 
  the 
  wave-lengths 
  of 
  which 
  were 
  measured. 
  

   No 
  trace 
  of 
  the 
  hydrogen 
  lines 
  was 
  observed 
  in 
  this 
  or 
  in 
  

   the 
  other 
  experiments. 
  After 
  the 
  discharge 
  had 
  passed 
  at 
  

   intervals 
  for 
  two 
  hours, 
  most 
  of 
  the 
  lines 
  due 
  to 
  the 
  emana- 
  

   tion 
  disappeared. 
  The 
  greater 
  part 
  of 
  the 
  emanation 
  was 
  

   then 
  found 
  to 
  be 
  sticking 
  to 
  the 
  surface 
  of 
  the 
  capillary, 
  as 
  

   in 
  the 
  previous 
  experiment. 
  The 
  prominence 
  of 
  the 
  carbon 
  

   dioxide 
  spectrum 
  cannot 
  I 
  think 
  be 
  ascribed 
  to 
  the 
  presence 
  

   of 
  a 
  considerable 
  amount 
  of 
  this 
  gas 
  mixed 
  with 
  the 
  emana- 
  

   tion 
  before 
  the 
  discharge 
  passed, 
  but 
  rather 
  to 
  the 
  production 
  

   of 
  this 
  gas 
  by 
  the 
  discharge, 
  due 
  probably 
  to 
  the 
  presence 
  

   of 
  a 
  trace 
  of 
  some 
  organic 
  matter 
  at 
  the 
  surface 
  of 
  the 
  

   mercury. 
  The 
  correctness 
  of 
  this 
  view 
  was 
  confirmed 
  by 
  

   the 
  observation 
  that 
  the 
  spectrum 
  of 
  carbon 
  dioxide 
  was 
  

   unaltered 
  in 
  brightness, 
  after 
  practically 
  all 
  the 
  residual 
  

  

  