﻿C. 
  L. 
  Speyers 
  — 
  Boiling 
  Point 
  Curves. 
  

  

  341 
  

  

  Art. 
  XXXI. 
  — 
  Some 
  Boiling 
  Point 
  Curves 
  ; 
  by 
  C. 
  L. 
  Speyers. 
  

  

  Ix 
  several 
  preceding 
  papers'* 
  the 
  equation 
  

   n 
  p—p' 
  

  

  N 
  + 
  rc 
  

  

  P 
  

  

  was 
  used 
  to 
  get 
  at 
  the 
  molecular 
  weights 
  of 
  liquids 
  in 
  homo- 
  

   geneous 
  liquid 
  mixtures 
  and 
  apparently 
  with 
  success, 
  since 
  the 
  

   values 
  so 
  obtained 
  were 
  altogether 
  reasonable. 
  

  

  On 
  the 
  other 
  hand, 
  knowing 
  the 
  molecular 
  aggregations 
  of 
  

   the 
  constituents 
  in 
  a 
  homogeneous 
  mixture 
  of 
  two 
  liquids, 
  it 
  is 
  

   possible 
  to 
  plot 
  the 
  boiling 
  point 
  curve 
  of 
  such 
  a 
  mixture. 
  

  

  For 
  example, 
  the 
  boiling 
  point 
  curve 
  under 
  760 
  mm 
  Hg 
  of 
  a 
  

   mixture 
  of 
  carbon 
  tetrachlorid 
  and 
  benzene 
  is 
  calculated 
  in 
  the 
  

   following 
  way. 
  The 
  molecular 
  weights 
  of 
  these 
  liquids 
  are 
  

   probably 
  normal. 
  Wherefore, 
  since 
  N 
  + 
  ^ 
  = 
  100, 
  the 
  above 
  

   equation 
  becomes 
  the 
  equation 
  to 
  a 
  straight 
  liue 
  for 
  each 
  con- 
  

   stituent 
  and 
  the 
  vapor-pressure 
  plot 
  of 
  the 
  mixture 
  is 
  a 
  straight 
  

   line 
  which 
  has 
  the 
  vapor-pressures 
  of 
  the 
  two 
  pure 
  constituents 
  

   for 
  its 
  terminals. 
  Fig. 
  1 
  shows 
  the 
  vapor-pressure 
  plots 
  of 
  the 
  

  

  too 
  

  

  C 
  L 
  H 
  b 
  

  

  

  90' 
  - 
  

  

  

  COL 
  

  

  mixture 
  at 
  different 
  temperatures. 
  The 
  abscissae 
  give 
  the 
  

   molecular 
  percentages 
  of 
  carbon 
  tetrachlorid 
  ; 
  the 
  ordinates 
  

   give 
  the 
  pressure 
  in 
  mm 
  Hg. 
  The 
  data 
  were 
  taken 
  from 
  

   Winkelmann.f 
  At 
  81° 
  the 
  vapor 
  pressures 
  of 
  carbon 
  tetra- 
  

   chlorid 
  and 
  of 
  benzene 
  are 
  both 
  above 
  760 
  mm 
  and 
  at 
  76° 
  their 
  

   vapor 
  pressures 
  are 
  both 
  below 
  760 
  mm 
  , 
  so 
  that 
  the 
  boiling 
  tem- 
  

   perature 
  of 
  this 
  mixture 
  lies 
  between 
  76° 
  and 
  81°. 
  Laying 
  off 
  

   the 
  compositions 
  given 
  by 
  the 
  several 
  lines 
  at 
  the 
  points 
  where 
  

   they 
  intersect 
  the 
  horizontal 
  pressure 
  line 
  of 
  760 
  mm 
  , 
  the 
  points 
  

   shown 
  by 
  x 
  in 
  rig. 
  2, 
  plot 
  I, 
  are 
  obtained, 
  giving 
  the 
  theoretical 
  

  

  *Joum. 
  Phys. 
  Chem., 
  ii, 
  347, 
  362, 
  1898; 
  Journ. 
  Am. 
  Chem. 
  Soc, 
  xxi, 
  282, 
  

   725, 
  1899. 
  

   fHandb. 
  d. 
  Phys, 
  II 
  2 
  , 
  812, 
  814. 
  

  

  