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  Rayleigh 
  and 
  Ramsay 
  — 
  Argon 
  , 
  a 
  New 
  

  

  account 
  of 
  the 
  spectrum 
  in 
  a 
  separate 
  communication, 
  has 
  

   kindly 
  furnished 
  us 
  with 
  the 
  accurate 
  wave-lengths 
  of 
  these 
  

   lines, 
  as 
  well 
  as 
  of 
  some 
  others 
  next 
  to 
  be 
  described 
  ; 
  they 
  are 
  

   respectively 
  696*56 
  and 
  705*64, 
  10" 
  6 
  mm. 
  

  

  Besides 
  these 
  red 
  lines, 
  a 
  bright 
  yellow 
  line, 
  more 
  refrangible 
  

   than 
  the 
  sodium 
  line, 
  occurs 
  at 
  603*84. 
  A 
  group 
  of 
  five 
  bright 
  

   green 
  lines 
  occurs 
  next, 
  besides 
  a 
  number 
  of 
  less 
  intensity. 
  Of 
  

   the 
  group 
  of 
  five, 
  the 
  second, 
  which 
  is 
  perhaps 
  the 
  most 
  bril- 
  

   liant, 
  has 
  the 
  wave-length 
  561*00. 
  There 
  is 
  next 
  a 
  blue 
  or 
  

   blue-violet 
  line 
  of 
  wave-length 
  470*2 
  ; 
  and 
  last, 
  in 
  the 
  less 
  

   easily 
  visible 
  part 
  of 
  the 
  spectrum, 
  there 
  are 
  five 
  strong 
  violet 
  

   lines, 
  of 
  which 
  the 
  fourth, 
  which 
  is 
  the 
  most 
  brilliant, 
  has 
  the 
  

   wave-length 
  420*0. 
  

  

  Unfortunately, 
  the 
  red 
  lines, 
  which 
  are 
  not" 
  to 
  be 
  mistaken 
  

   for 
  those 
  of 
  any 
  other 
  substance, 
  are 
  not 
  easily 
  seen 
  when 
  a 
  

   jar 
  discharge 
  is 
  passed 
  through 
  argon 
  at 
  atmospheric 
  pressure. 
  

   The 
  spectrum 
  seen 
  under 
  these 
  conditions 
  has 
  been 
  examined 
  

   by 
  Professor 
  Schuster. 
  The 
  most 
  characteristic 
  lines 
  are 
  per- 
  

   haps 
  those 
  in 
  the 
  neighborhood 
  of 
  F, 
  and 
  are 
  very 
  easily 
  

   seen 
  if 
  there 
  be 
  not 
  too 
  much 
  nitrogen, 
  in 
  spite 
  of 
  the 
  presence 
  

   of 
  some 
  oxygen 
  and 
  water 
  vapor. 
  The 
  approximate 
  wave- 
  

   lengths 
  are 
  — 
  

  

  487-91 
  _ 
  Strong. 
  

  

  [486*07] 
  F. 
  

  

  484 
  *7 
  1 
  Not 
  quite 
  so 
  strong. 
  

  

  480*52 
  Strong. 
  

  

  AhQ.-o 
  ( 
  Fairly 
  strong 
  charac- 
  

  

  472-" 
  6 
  \ 
  teristic 
  triplet. 
  

  

  It 
  is 
  necessary 
  to 
  anticipate 
  Mr. 
  Crookes's 
  communication, 
  

   and 
  to 
  state 
  that 
  when 
  the 
  current 
  is 
  passed 
  from 
  the 
  induction 
  

   coil 
  in 
  one 
  direction, 
  that 
  end 
  of 
  the 
  capillary 
  tube 
  next 
  the 
  

   positive 
  pole 
  appears 
  of 
  a 
  redder, 
  and 
  that 
  next 
  the 
  negative 
  

   pole 
  of 
  a 
  bluer 
  hue. 
  There 
  are, 
  in 
  effect, 
  two 
  spectra, 
  which 
  

   Mr. 
  Crookes 
  has 
  succeeded 
  in 
  separating 
  to 
  a 
  considerable 
  

   extent. 
  Mr. 
  E. 
  C. 
  Baly,* 
  who 
  has 
  noticed 
  a 
  similar 
  phenom- 
  

   enon, 
  attributes 
  it 
  to 
  the 
  presence 
  of 
  two 
  gases. 
  He 
  says 
  : 
  — 
  

   " 
  When 
  an 
  electric 
  current 
  is 
  passed 
  through 
  a 
  mixture 
  of 
  two 
  

   gases, 
  one 
  is 
  separated 
  from 
  the 
  other 
  and 
  appears 
  in 
  the 
  nega- 
  

   tive 
  glow." 
  The 
  conclusion 
  would 
  follow 
  that 
  what 
  we 
  have 
  

   termed 
  " 
  argon 
  " 
  is 
  in 
  reality 
  a 
  mixture 
  of 
  two 
  gases 
  which 
  

   have 
  as 
  yet 
  not 
  been 
  separated. 
  This 
  conclusion, 
  if 
  true, 
  is 
  of 
  

   great 
  importance, 
  and 
  experiments 
  are 
  now 
  in 
  progress 
  to 
  test 
  

   it 
  by 
  the 
  use 
  of 
  other 
  physical 
  methods. 
  The 
  full 
  bearing 
  of 
  

   this 
  possibility 
  will 
  appear 
  later. 
  

  

  * 
  Proc. 
  Phys. 
  Soc, 
  1893, 
  p. 
  147. 
  

  

  