﻿394 
  Linebarger 
  — 
  Some 
  Relations 
  between 
  Temperature, 
  

  

  gives 
  a 
  greater 
  value, 
  it 
  must 
  be 
  associated 
  in 
  the 
  liquid 
  state 
  

   alone. 
  The 
  greater 
  the 
  variation 
  from 
  the 
  normal 
  value 
  of 
  

   the 
  " 
  constant," 
  the 
  greater 
  the 
  amount 
  of 
  the 
  association. 
  

   Thus 
  far, 
  we 
  have 
  considered 
  the 
  application 
  of 
  the 
  formula 
  

  

  =-— 
  = 
  const, 
  only 
  to 
  determinations 
  made 
  under 
  the 
  pressure 
  

  

  Jiabs 
  

  

  of 
  about 
  one 
  atmosphere. 
  But 
  how 
  will 
  it 
  be 
  at 
  other 
  pres- 
  

   sures 
  and 
  hence 
  other 
  temperatures 
  ? 
  All 
  of 
  the 
  deductions 
  of 
  

   the 
  formula 
  have 
  been 
  made 
  on 
  the 
  assumption 
  that 
  the 
  pres- 
  

   sure 
  was 
  that 
  of 
  one 
  atmosphere, 
  with 
  the 
  exception 
  of 
  the 
  one 
  

   developed 
  by 
  Le 
  Chatelier, 
  which 
  contains 
  a 
  term 
  referring 
  to 
  

   pressure 
  (Equation 
  17). 
  This 
  equation, 
  however, 
  was 
  derived 
  

   on 
  the 
  supposition 
  that 
  the 
  latent 
  heat 
  of 
  vaporization 
  is 
  inde- 
  

   pendent 
  of 
  temperature 
  and 
  pressure 
  ; 
  such 
  an 
  assumption, 
  

   however, 
  does 
  not 
  accord 
  with 
  the 
  experimental 
  results 
  

   obtained 
  by 
  Regnault, 
  Ramsay 
  and 
  Young, 
  Jahn, 
  and 
  others. 
  

   The 
  heat 
  of 
  vaporization 
  of 
  a 
  liquid 
  decreases 
  with 
  rise 
  of 
  

   temperature 
  and 
  concomitant 
  increase 
  of 
  pressure 
  until 
  at 
  the 
  

   critical 
  point 
  it 
  becomes 
  equal 
  to 
  zero. 
  Yet 
  for 
  all 
  tempera- 
  

   tures 
  and 
  concurrent 
  pressures 
  below 
  the 
  critical, 
  the 
  relation 
  

   (17) 
  obtains, 
  and 
  the 
  lower 
  the 
  temperature, 
  the 
  larger 
  the 
  

   " 
  constant." 
  The 
  number 
  of 
  reliable 
  data 
  at 
  hand 
  for 
  the 
  com- 
  

   parison 
  of 
  the 
  theory 
  with 
  experiment 
  at 
  other 
  pressures 
  than 
  

   the 
  atmospheric 
  is 
  relatively 
  small. 
  Most 
  of 
  them 
  have 
  been 
  

   made 
  at 
  the 
  freezing 
  point 
  of 
  water 
  under 
  the 
  pressure 
  of 
  the 
  

   saturated 
  vapor 
  at 
  that 
  temperature. 
  In 
  Table 
  II 
  are 
  given 
  

   such 
  data 
  as 
  are 
  reliable, 
  and 
  only 
  for 
  normal 
  liquids. 
  In 
  the 
  

   first 
  column 
  is 
  given 
  a 
  reference 
  number 
  to 
  the 
  investigator's 
  

   names 
  and 
  places 
  of 
  publication, 
  — 
  directly 
  below 
  the 
  table. 
  

   Columns 
  a, 
  b, 
  c, 
  and 
  d 
  give 
  the 
  name, 
  formula, 
  molecular 
  mass, 
  

   and 
  the 
  latent 
  heat 
  of 
  vaporization, 
  respectively 
  of 
  the 
  liquids 
  

   in 
  question. 
  The 
  sixth 
  (e) 
  column 
  contains 
  the 
  value 
  of 
  the 
  

  

  expression 
  — 
  — 
  , 
  and 
  the 
  seventh 
  (f) 
  the 
  value 
  of 
  twice 
  the 
  

  

  Labs 
  

  

  natural 
  logarithm 
  of 
  the 
  pressure. 
  (The 
  pressure 
  in 
  the 
  case 
  

   of 
  such 
  liquids 
  as 
  have 
  had 
  their 
  vapor 
  tension 
  determined 
  is 
  

   generally 
  set 
  as 
  equal 
  to 
  that 
  of 
  the 
  saturated 
  vapor 
  at 
  0° 
  ; 
  for 
  

   the 
  others, 
  the 
  pressure 
  has 
  been 
  put 
  at 
  60 
  mm 
  of 
  mercury, 
  as 
  

   Jahn, 
  in 
  his 
  experiments, 
  reduced 
  the 
  pressure 
  to 
  this 
  point 
  

   before 
  allowing 
  evaporation 
  to 
  take 
  place, 
  and 
  the 
  others 
  exam- 
  

   ined 
  by 
  him 
  have 
  not 
  been 
  investigated 
  thoroughly 
  as 
  regards 
  

   their 
  vapor 
  tensions. 
  The 
  pressure 
  is 
  reduced 
  to 
  absolute 
  

   measure 
  by 
  multiplication 
  by 
  13*6.) 
  The 
  last 
  column 
  gives 
  the 
  

   value 
  of 
  Le 
  Chatelier' 
  s 
  relation 
  (17), 
  obtained 
  by 
  adding 
  the 
  

   values 
  found 
  in 
  columns 
  e 
  andy 
  for 
  each 
  liquid. 
  

  

  