﻿114 
  

  

  Mr. 
  G. 
  F. 
  Rodwell 
  on 
  the 
  

  

  [Dec. 
  10, 
  

  

  I 
  115-0565 
  

  

  II 
  114-7232 
  

  

  III 
  114-9458 
  

  

  IV 
  , 
  114-7318 
  

  

  Mean= 
  114-8643 
  

  

  From 
  this 
  we 
  deduce 
  that 
  a 
  volume 
  of 
  paraffine 
  =100 
  at 
  32° 
  F. 
  will 
  

   equal 
  113*8447 
  at 
  142° 
  F. 
  iu 
  the 
  fluid 
  state 
  ; 
  and 
  if 
  we 
  subtract 
  the 
  

   expansion 
  between 
  32° 
  and 
  142° 
  F. 
  of 
  the 
  solid, 
  we 
  find 
  that 
  the 
  actual 
  

   expansion 
  of 
  the 
  semisolid 
  paraffine 
  in 
  passing 
  into 
  the 
  perfect 
  liquid 
  will 
  

   be 
  3*1473 
  on 
  the 
  volume 
  100 
  at 
  32° 
  taken 
  as 
  the 
  starting-point. 
  

  

  Determination 
  of 
  the 
  coefficient 
  of 
  expansion 
  of 
  liquid 
  paraffine 
  between 
  

   142° 
  F. 
  and 
  its 
  boiling-point 
  {presumably 
  about 
  750° 
  F.). 
  

  

  The 
  paraffine 
  was 
  heated 
  in 
  tubes 
  of 
  known 
  weight 
  and 
  capacity 
  in 
  a 
  

   bath 
  of 
  paraffine, 
  and 
  the 
  weight 
  of 
  paraffine 
  which 
  exuded 
  between 
  any- 
  

   observed 
  range 
  of 
  temperature 
  was 
  determined. 
  Specific-gravity 
  flasks 
  

   with 
  capillary 
  stoppers 
  were 
  found 
  to 
  be 
  unsuitable 
  for 
  the 
  determina- 
  

   tions, 
  on 
  accoUut 
  of 
  the 
  difficulty 
  of 
  uniformly 
  heating 
  the 
  mass 
  of 
  liquid 
  

   within 
  them. 
  Many 
  attempts 
  were 
  made 
  to 
  determine 
  the 
  increase 
  of 
  

   the 
  coefficient 
  with 
  the 
  temperature, 
  but 
  the 
  results 
  were 
  not 
  satisfac- 
  

   tory 
  ; 
  hence 
  I 
  can 
  only 
  give 
  the 
  mean 
  coefficient 
  of 
  expansion 
  between 
  

   the 
  melting-point 
  and 
  the 
  boiling-point. 
  

  

  The 
  result 
  of 
  many 
  experiments 
  gave 
  

  

  •000593 
  

  

  as 
  the 
  mean 
  coefficient 
  of 
  expansion 
  of 
  the 
  liquid. 
  The 
  following 
  are 
  

   records 
  of 
  some 
  of 
  the 
  determinations 
  : 
  — 
  

  

  A 
  volume 
  of 
  liquid 
  paraffine 
  at 
  142° 
  F. 
  being 
  taken 
  at 
  100, 
  

  

  

  

  Found. 
  

  

  Calculated. 
  

  

  Volume 
  at 
  

  

  200° 
  F. 
  

  

  = 
  103-4951 
  

  

  103-4394 
  

  

  >> 
  }» 
  

  

  250° 
  

  

  = 
  106-4766 
  

  

  106-4044 
  

  

  »> 
  j> 
  

  

  300° 
  

  

  = 
  108-9820 
  

  

  109-3694 
  

  

  J5 
  J> 
  

  

  350° 
  

  

  = 
  112-6365 
  

  

  112-3344 
  

  

  •>1 
  55 
  

  

  400° 
  

  

  = 
  116-4143 
  

  

  115-2994 
  

  

  55 
  55 
  

  

  500° 
  

  

  = 
  122-3S14 
  

  

  121-2294 
  

  

  55 
  55 
  

  

  600° 
  

  

  = 
  127-2905 
  

  

  127-1594 
  

  

  „ 
  boilin 
  

  

  g-point 
  

  

  = 
  135-3344 
  

  

  136-0544 
  

  

  The 
  volume 
  at 
  the 
  boiliug-point 
  is 
  calculated 
  on 
  the 
  supposition 
  that 
  it 
  

   is 
  750° 
  F., 
  near 
  to 
  which 
  it 
  certainly 
  must 
  be 
  ; 
  the 
  volume 
  found 
  corre- 
  

   sponds, 
  if 
  we 
  employ 
  the 
  above 
  coefficient 
  of 
  expansion, 
  to 
  744° 
  F. 
  

   (395°-5C). 
  

  

  Summarizing 
  the 
  above 
  results 
  we 
  obtain 
  the 
  following 
  Table, 
  which 
  

   represents 
  the 
  volumes 
  of 
  a 
  mass 
  of 
  paraffine 
  (taken 
  at 
  100 
  at 
  32° 
  F., 
  

  

  