﻿292 
  Rayleigh 
  and 
  Ramsay 
  — 
  Argon, 
  a 
  New 
  

  

  — 
  90°, 
  failed. 
  ~No 
  appearance 
  of 
  liquefaction 
  could 
  be 
  

   observed. 
  

  

  Professor 
  Charles 
  Olszewski, 
  of 
  Cracow, 
  the 
  well-known 
  

   authority 
  on 
  the 
  constants 
  of 
  liquefied 
  gases 
  at 
  low 
  tempera- 
  

   tures, 
  kindly 
  offered 
  to 
  make 
  experiments 
  on 
  the 
  liquefaction 
  

   of 
  argon. 
  His 
  results 
  are 
  embodied 
  in 
  a 
  separate 
  communica- 
  

   tion, 
  but 
  it 
  is 
  allowable 
  to 
  state 
  here 
  that 
  the 
  gas 
  has 
  a 
  lower 
  

   critical 
  temperature 
  ( 
  — 
  121°) 
  and 
  a 
  lower 
  boiling 
  point 
  ( 
  — 
  187°) 
  

   than 
  oxygen, 
  and 
  that 
  he 
  has 
  succeeded 
  in 
  solidifying 
  argon 
  to 
  

   white 
  crystals, 
  melting 
  at 
  — 
  189*6°. 
  The 
  density 
  of 
  the 
  liquid 
  

   is 
  approximately 
  1*5, 
  that 
  of 
  oxygen 
  being 
  1*124, 
  and 
  of 
  nitro- 
  

   gen 
  0*885. 
  The 
  sample 
  of 
  gas 
  he 
  experimented 
  with 
  was 
  

   exceptionally 
  pure, 
  and 
  had 
  been 
  prepared 
  by 
  help 
  of 
  magne- 
  

   sium. 
  It 
  showed 
  no 
  trace 
  of 
  nitrogen 
  when 
  examined 
  in 
  a 
  

   vacuum 
  tube. 
  

  

  XIV. 
  Ratio 
  of 
  Specific 
  Heats. 
  

  

  In 
  order 
  to 
  decide 
  regarding 
  the 
  elementary 
  or 
  compound 
  

   nature 
  of 
  argon, 
  experiments 
  were 
  made 
  on 
  the 
  velocity 
  of 
  

   sound 
  in 
  it. 
  It 
  will 
  be 
  remembered 
  that, 
  from 
  the 
  velocity 
  of 
  

   sound 
  in 
  a 
  gas, 
  the 
  ratio 
  of 
  specific 
  heat 
  at 
  constant 
  pressure 
  

   to 
  that 
  at 
  constant 
  volume 
  can 
  be 
  deduced 
  by 
  means 
  of 
  the 
  

   equation 
  

  

  nk 
  = 
  v 
  

  

  /1> 
  + 
  ^H 
  

  

  when 
  n 
  is 
  the 
  frequency, 
  X 
  the 
  wave-length 
  of 
  sound, 
  v 
  its 
  

   velocity, 
  e 
  the 
  isothermal 
  elasticity, 
  d 
  the 
  density, 
  (1 
  -f 
  at) 
  the 
  

   temperature 
  correction, 
  C 
  p 
  the 
  specific 
  heat 
  at 
  constant 
  pres- 
  

   sure, 
  and 
  C 
  v 
  that 
  at 
  constant 
  volume. 
  In 
  comparing 
  two 
  

   gases 
  at 
  the 
  same 
  temperature, 
  each 
  of 
  which 
  obeys 
  Boyle's 
  

   law 
  with 
  sufficient 
  approximation, 
  and 
  in 
  using 
  the 
  same 
  sound, 
  

   many 
  of 
  these 
  terms 
  disappear, 
  and 
  the 
  ratio 
  of 
  specific 
  heats 
  

   of 
  one 
  gas 
  may 
  be 
  deduced 
  from 
  that 
  of 
  the 
  other, 
  if 
  known, 
  

   by 
  means 
  of 
  the 
  proportion 
  

  

  ICd: 
  Wd'i: 
  1-41 
  : 
  x 
  

  

  where, 
  for 
  example, 
  X 
  and 
  d 
  refer 
  to 
  air, 
  of 
  which 
  the 
  ratio 
  is 
  

   1*4:1, 
  according 
  to 
  observations 
  by 
  Rontgen, 
  Wiillner, 
  Kayser, 
  

   and 
  Jarain 
  and 
  Richard. 
  

  

  Two 
  completely 
  different 
  series 
  of 
  observations, 
  one 
  in 
  a 
  

   tube 
  of 
  about 
  2mm. 
  diameter, 
  and 
  one 
  in 
  one 
  of 
  8mm., 
  made 
  

   with 
  entirely 
  different 
  samples 
  of 
  gas, 
  gave, 
  the 
  first, 
  1*65 
  as 
  

   the 
  ratio, 
  and, 
  the 
  second, 
  1*61. 
  

  

  Experiments 
  made 
  with 
  the 
  first 
  tube, 
  to 
  test 
  the 
  accuracy 
  

   of 
  its 
  working, 
  gave 
  for 
  carbon 
  dioxide 
  the 
  ratio 
  1*276, 
  instead 
  

  

  