﻿386 
  Linebarger 
  — 
  Some 
  Relations 
  between 
  Temperature, 
  

  

  2l 
  ° 
  g 
  f 
  +P 
  (i"i) 
  = 
  0, 
  (16) 
  

  

  This 
  equation 
  contains 
  no 
  constant, 
  but 
  if 
  the 
  terms 
  T 
  and 
  p 
  , 
  

   which 
  together 
  form 
  a 
  constant, 
  be 
  transferred 
  to 
  the 
  second 
  

   member, 
  the 
  equation 
  

  

  2 
  log 
  p 
  + 
  ;=- 
  z= 
  constant 
  (1 
  7) 
  

  

  is 
  obtained, 
  and 
  if 
  the 
  pressure 
  be 
  kept 
  constant. 
  

  

  =-=z 
  constant, 
  (18) 
  

  

  or, 
  if 
  p 
  be 
  taken 
  as 
  the 
  heat 
  of 
  vaporization 
  of 
  the 
  unit 
  of 
  

   mass 
  of 
  liquid, 
  

  

  -=- 
  = 
  constant. 
  (18 
  bis) 
  

  

  It 
  is 
  seen 
  from 
  the 
  foregoing 
  that 
  the 
  constancy 
  of 
  the 
  quo- 
  

   tient 
  of 
  the 
  molecular 
  heat 
  of 
  vaporization 
  by 
  the 
  absolute 
  

   temperature 
  at 
  which 
  the 
  vaporization 
  takes 
  place 
  has 
  been 
  

   arrived 
  at 
  by 
  various 
  scientists 
  in 
  different 
  ways. 
  This 
  in 
  itself 
  

   is 
  strong 
  warrant 
  for 
  the 
  truth 
  of 
  the 
  relation. 
  Still 
  there 
  

   exist 
  certain 
  discrepancies 
  between 
  the 
  theory 
  and 
  the 
  experi- 
  

   mental 
  determinations, 
  which 
  must 
  be 
  accounted 
  for. 
  Before 
  

   taking 
  up 
  their 
  consideration, 
  however, 
  it 
  is 
  necessary 
  to 
  pass 
  

   in 
  review 
  what 
  experimental 
  work 
  has 
  been 
  done. 
  

  

  II. 
  

  

  In 
  Table 
  I 
  are 
  given 
  the 
  latent 
  heats 
  of 
  vaporization 
  of 
  a 
  

   number 
  of 
  liquids, 
  which 
  have 
  been 
  determined 
  by 
  direct 
  

   experiment 
  at 
  or 
  near 
  the 
  ordinary 
  atmospheric 
  pressure. 
  

   Only 
  such 
  liquids 
  as 
  are 
  chemical 
  units 
  are 
  admitted, 
  solutions 
  

   of 
  acids 
  and 
  the 
  like 
  being 
  excluded 
  ; 
  also 
  the 
  determinations 
  

   made 
  with 
  very 
  volatile 
  liquids, 
  such 
  as 
  ammonia, 
  sulphur 
  

   dioxide, 
  etc., 
  are 
  omitted. 
  With 
  these 
  exceptions 
  it 
  is 
  believed 
  

   that 
  no 
  omissions 
  of 
  importance 
  have 
  been 
  made. 
  

  

  The 
  first 
  column 
  refers 
  to 
  the 
  " 
  References 
  ;" 
  the 
  second 
  

   column 
  {a) 
  gives 
  the 
  name 
  of 
  the 
  liquids 
  ; 
  the 
  third 
  (b) 
  

   their 
  formula, 
  and 
  the 
  fourth 
  (c) 
  their 
  molecular 
  masses 
  ; 
  in 
  

   the 
  fifth 
  (d) 
  and 
  sixth 
  (e) 
  columns 
  are 
  contained 
  the 
  tem- 
  

   peratures 
  at 
  which 
  vaporization 
  took 
  place 
  and 
  the 
  latent 
  

   heats 
  for 
  one 
  gram 
  of 
  the 
  liquid 
  in 
  heat 
  units 
  of 
  which 
  one 
  

   warms 
  one 
  gram 
  of 
  water 
  from 
  0° 
  to 
  1° 
  C, 
  while 
  the 
  seventh 
  

   {f) 
  column 
  shows 
  the 
  quotient 
  obtained 
  by 
  dividing 
  the 
  

   molecular 
  heat 
  of 
  vaporization 
  by 
  the 
  absolute 
  temperature. 
  

   The 
  eighth 
  column 
  (g) 
  gives 
  the 
  pressure 
  in 
  rounded 
  milli- 
  

   meters 
  of 
  mercury 
  ; 
  when 
  the 
  pressure 
  has 
  not 
  been 
  indicated 
  

   by 
  the 
  investigator, 
  the 
  space 
  has 
  been 
  left 
  vacant 
  ; 
  however, 
  

   from 
  the 
  nature 
  of 
  the 
  methods, 
  the 
  pressure 
  cannot 
  vary 
  

   greatly 
  from 
  normal 
  atmospheric 
  pressure. 
  

  

  