﻿284 
  Rayleigh 
  and 
  Ramsay 
  — 
  Argon, 
  a 
  New 
  

  

  volume 
  was 
  still 
  further 
  reduced, 
  the 
  density 
  of 
  the 
  residue 
  

   was 
  increased 
  to 
  19-09. 
  

  

  On 
  passing 
  sparks 
  for 
  several 
  hours 
  through 
  a 
  mixture 
  of 
  a 
  

   small 
  quantity 
  of 
  this 
  gas 
  with 
  oxygen, 
  its 
  volume 
  was 
  still 
  

   further 
  reduced. 
  Assuming 
  that 
  this 
  reduction 
  was 
  due 
  to 
  the 
  

   further 
  elimination 
  of 
  nitrogen, 
  the 
  density 
  of 
  the 
  remaining 
  

   gas 
  was 
  calculated 
  to 
  be 
  20*0. 
  

  

  The 
  spectrum 
  of 
  the 
  gas 
  of 
  density 
  19'09, 
  though 
  showing 
  

   nitrogen 
  bands, 
  showed 
  many 
  other 
  lines 
  which 
  were 
  not 
  

   recognizable 
  as 
  belonging 
  to 
  any 
  known 
  element. 
  

  

  VI. 
  Proof 
  of 
  the 
  presence 
  of 
  Argon 
  in 
  Air 
  by 
  means 
  of 
  

  

  Aimolysis. 
  

  

  It 
  has 
  already 
  (§ 
  2) 
  been 
  suggested 
  that 
  if 
  " 
  atmospheric 
  

   nitrogen" 
  contains 
  two 
  gases 
  of 
  different 
  densities, 
  it 
  should 
  

   be 
  possible 
  to 
  obtain 
  direct 
  evidence 
  of 
  the 
  fact 
  by 
  the 
  method 
  

   of 
  atmolysis. 
  The 
  present 
  section 
  contains 
  an 
  account 
  of 
  care- 
  

   fully 
  conducted 
  experiments 
  directed 
  to 
  this 
  end. 
  

  

  The 
  atmolyser 
  was 
  prepared 
  (after 
  Graham) 
  by 
  combining 
  a 
  

   number 
  of 
  "churchwarden" 
  tobacco 
  pipes. 
  At 
  first 
  twelve 
  

   pipes 
  were 
  used 
  in 
  three 
  groups, 
  each 
  group 
  including 
  four 
  

   pipes 
  connected 
  in 
  series. 
  The 
  three 
  groups 
  were 
  then 
  con- 
  

   nected 
  in 
  parallel, 
  and 
  placed 
  in 
  a 
  large 
  glass 
  tube 
  closed 
  in 
  

   such 
  a 
  way 
  that 
  a 
  partial 
  vacuum 
  could 
  be 
  maintained 
  in 
  the 
  

   space 
  outside 
  the 
  pipes 
  by 
  a 
  water 
  pump. 
  One 
  end 
  of 
  the 
  

   combination 
  of 
  pipes 
  was 
  open 
  to 
  the 
  atmosphere 
  ; 
  the 
  other 
  

   end 
  was 
  connected 
  to 
  a 
  bottle 
  aspirator, 
  initially 
  full 
  of 
  water, 
  

   and 
  so 
  arranged 
  as 
  to 
  draw 
  about 
  2 
  per 
  cent 
  of 
  the 
  air 
  which 
  

   entered 
  the 
  other 
  end 
  of 
  the 
  pipes. 
  The 
  gas 
  collected 
  was 
  

   thus 
  a 
  very 
  small 
  proportion 
  of 
  that 
  which 
  leaked 
  through 
  the 
  

   pores 
  of 
  the 
  pipes, 
  and 
  should 
  be 
  relatively 
  rich 
  in 
  the 
  heavier 
  

   constituents 
  of 
  the 
  atmosphere. 
  The 
  flow 
  of 
  water 
  from 
  the 
  

   aspirator 
  could 
  not 
  be 
  maintained 
  very 
  constant, 
  but 
  the 
  rate 
  

   of 
  2 
  per 
  cent 
  was 
  never 
  much 
  exceeded. 
  

  

  The 
  air 
  thus 
  obtained 
  was 
  treated 
  exactly 
  as 
  ordinary 
  air 
  had 
  

   been 
  treated 
  in 
  determinations 
  of 
  the 
  density 
  of 
  atmospheric 
  

   nitrogen. 
  Oxygen 
  was 
  removed 
  by 
  red-hot 
  copper, 
  followed 
  

   by 
  cupric 
  oxide, 
  ammonia 
  by 
  sulphuric 
  acid, 
  moisture 
  and 
  car- 
  

   bonic 
  acid 
  by 
  potash 
  and 
  phosphoric 
  anhydride. 
  

  

  In 
  a 
  total 
  weight 
  of 
  approximately 
  2 
  '3 
  grams 
  the 
  excess 
  of 
  

   weight 
  of 
  the 
  diffused 
  nitrogen 
  over 
  ordinary, 
  atmospheric 
  

   nitrogen 
  was 
  in 
  four 
  experiments, 
  0-0049, 
  0*0014, 
  0-0027, 
  

   0-0015. 
  

  

  The 
  mean 
  excess 
  of 
  the 
  four 
  determinations 
  is 
  0-00262 
  gram, 
  

   or, 
  if 
  we 
  omit 
  the 
  first, 
  which 
  depended 
  upon 
  a 
  vacuum 
  

   weighing 
  of 
  two 
  months 
  old, 
  0-00187 
  gram. 
  

  

  