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  Rayleigh 
  and 
  Ramsay 
  — 
  Argon, 
  a 
  New 
  

  

  and 
  the 
  uniformity 
  in 
  the 
  density 
  of 
  samples 
  of 
  chemical 
  

   nitrogen 
  prepared 
  from 
  different 
  compounds, 
  lead 
  to 
  the 
  con- 
  

   clusion 
  that 
  the 
  cause 
  of 
  the 
  anomaly 
  is 
  the 
  presence 
  of 
  a 
  

   heavy 
  gas 
  in 
  air. 
  If 
  that 
  gas 
  possess 
  the 
  density 
  20 
  compared 
  

   with 
  hydrogen, 
  " 
  atmospheric 
  " 
  nitrogen 
  should 
  contain 
  of 
  it 
  

   approximately 
  1 
  per 
  cent. 
  This 
  is, 
  in 
  fact, 
  found 
  to 
  be 
  the 
  

   case. 
  Moreover, 
  as 
  nitrogen 
  is 
  removed 
  from 
  air 
  by 
  means 
  of 
  

   red-hot 
  magnesium, 
  the 
  density 
  of 
  the 
  remaining 
  gas 
  rises 
  pro- 
  

   portionately 
  to 
  the 
  concentration 
  of 
  the 
  heavier 
  constituent. 
  

  

  Second. 
  This 
  gas 
  has 
  been 
  concentrated 
  in 
  the 
  atmosphere 
  

   by 
  diffusion. 
  It 
  is 
  true 
  that 
  it 
  has 
  not 
  been 
  freed 
  from 
  oxy- 
  

   gen 
  and 
  nitrogen 
  by 
  diffusion, 
  but 
  the 
  process 
  of 
  diffusion 
  

   increases, 
  relatively 
  to 
  nitrogen, 
  the 
  amount 
  of 
  argon 
  in 
  that 
  

   portion 
  which 
  does 
  not 
  pass 
  through 
  the 
  porous 
  walls. 
  This 
  

   has 
  been 
  proved 
  by 
  its 
  increase 
  in 
  density. 
  

  

  Third. 
  As 
  the 
  solubility 
  of 
  argon 
  in 
  water 
  is 
  relatively 
  high, 
  

   it 
  is 
  to 
  be 
  expected 
  that 
  the 
  density 
  of 
  the 
  mixture 
  of 
  argon 
  

   and 
  nitrogen, 
  pumped 
  out 
  of 
  water 
  along 
  with 
  oxygen, 
  should, 
  

   after 
  the 
  removal 
  of 
  the 
  oxygen, 
  be 
  higher 
  than 
  that 
  of 
  

   "atmospheric" 
  nitrogen. 
  Experiment 
  has 
  shown 
  that 
  the 
  

   density 
  is 
  considerably 
  increased. 
  

  

  Fourth. 
  It 
  is 
  in 
  the 
  highest 
  degree 
  improbable 
  that 
  two 
  

   processes, 
  so 
  different 
  from 
  each 
  other, 
  should 
  manufacture 
  

   the 
  same 
  product. 
  The 
  explanation 
  is 
  simple 
  if 
  it 
  be 
  granted 
  

   that 
  these 
  processes 
  merely 
  eliminate 
  nitrogen 
  from 
  an 
  " 
  atmos- 
  

   pheric" 
  mixture. 
  Moreover, 
  as 
  argon 
  is 
  an 
  element, 
  or 
  a 
  

   mixture 
  of 
  elements, 
  its 
  manufacture 
  would 
  mean 
  its 
  separa- 
  

   tion 
  from 
  one 
  of 
  the 
  substances 
  employed. 
  The 
  gas 
  which 
  

   can 
  be 
  removed 
  from 
  red-hot 
  magnesium 
  in 
  a 
  vacuum 
  has 
  

   been 
  found 
  to 
  be 
  wholly 
  hydrogen. 
  Nitrogen 
  from 
  chemical 
  

   sources 
  has 
  been 
  practically 
  all 
  absorbed 
  by 
  magnesium, 
  and 
  

   also 
  when 
  sparked 
  in 
  presence 
  of 
  oxygen 
  ; 
  hence 
  argon 
  cannot 
  

   have 
  resulted 
  from 
  the 
  decomposition 
  of 
  nitrogen. 
  That 
  it 
  is 
  

   not 
  produced 
  from 
  oxygen 
  is 
  sufficiently 
  borne 
  out 
  by 
  its 
  

   preparation 
  by 
  means 
  of 
  magnesium. 
  

  

  Other 
  arguments 
  could 
  be 
  adduced, 
  but 
  the 
  above 
  are 
  suffi- 
  

   cient 
  to 
  justify 
  the 
  conclusion 
  that 
  argon 
  is 
  present 
  in 
  the 
  

   atmosphere. 
  

  

  The 
  identity 
  of 
  the 
  leading 
  lines 
  in 
  the 
  spectrum, 
  the 
  simi- 
  

   lar 
  solubility 
  and 
  the 
  similar 
  density, 
  appear 
  to 
  prove 
  the 
  

   identity 
  of 
  the 
  argon 
  prepared 
  by 
  both 
  processes. 
  

  

  Argon 
  is 
  an 
  element, 
  or 
  a 
  mixture 
  of 
  elements, 
  for 
  Clausius 
  

   has 
  shown 
  that 
  if 
  K 
  be 
  the 
  energy 
  of 
  translators 
  motion 
  of 
  

   the 
  molecules 
  of 
  a 
  gas, 
  and 
  H 
  their 
  whole 
  kinetic 
  energy, 
  then 
  

  

  K_3(C,-C.) 
  

  

  H 
  - 
  2C, 
  ' 
  

  

  