﻿C. 
  Barus 
  — 
  Continuity 
  of 
  Solid 
  and 
  Liquid. 
  127 
  

  

  original 
  meniscus, 
  and 
  therefore 
  impracticable 
  both 
  to 
  arrive 
  

   at 
  the 
  volume 
  behavior 
  of 
  the 
  solid 
  and 
  to 
  rigorously 
  coordinate 
  

   successive 
  series 
  of 
  experiments. 
  

  

  3. 
  Advantages 
  of 
  the 
  method 
  of 
  this 
  paper. 
  — 
  Hence 
  I 
  en- 
  

   • 
  deavored 
  to 
  modify 
  Kopp's* 
  specific 
  volume 
  flask, 
  in 
  a 
  way 
  

  

  to 
  make 
  it 
  available 
  under 
  any 
  temperature 
  or 
  pressure. 
  Here 
  

   the 
  readings 
  are 
  independent 
  of 
  the 
  unbroken 
  character 
  of 
  the 
  

   meniscus 
  immediately 
  in 
  contact 
  with 
  the 
  solidifying 
  substance, 
  

   whereas 
  on 
  the 
  other 
  hand 
  (as 
  I 
  shall 
  presently 
  show), 
  the 
  

   volume 
  measurements 
  can 
  be 
  made 
  electrically,! 
  with 
  almost 
  

   every 
  desirable 
  degree 
  of 
  accuracy. 
  Furthermore 
  by 
  charging 
  

   the 
  flask 
  with 
  suitably 
  apportioned 
  quantities 
  of 
  substance 
  and 
  

   of 
  mercury, 
  the 
  error 
  due 
  to 
  the 
  compressibility 
  of 
  the 
  glass 
  

   may 
  be 
  eliminated 
  in 
  any 
  degree 
  whatever, 
  and 
  an 
  apparatus 
  be 
  

   obtained 
  which 
  is 
  practically 
  rigid 
  in 
  relation 
  to 
  pressure. 
  The 
  

   data 
  show 
  that 
  from 
  each 
  single 
  series 
  of 
  experiments 
  I 
  thus 
  

   obtain 
  the 
  isothermals 
  and 
  isopiestics 
  and 
  therefore 
  also 
  the 
  

   isometrics, 
  both 
  for 
  the 
  liquid 
  and 
  for 
  the 
  solid 
  state, 
  admitting 
  

   the 
  latter 
  to 
  be 
  less 
  accurate 
  ; 
  further, 
  the 
  relation 
  of 
  solidifica- 
  

   tion 
  and. 
  of 
  fusion 
  to 
  pressure, 
  and 
  finally, 
  the 
  pressure 
  changes 
  

   of 
  the 
  isothermal 
  specific 
  volumes 
  of 
  solid 
  and 
  liquid, 
  at 
  solidi- 
  

   fying 
  and 
  melting 
  points. 
  From 
  such 
  results 
  the 
  character 
  of 
  

   fusion, 
  and 
  the 
  probable 
  positions 
  of 
  critical, 
  § 
  26, 
  and 
  of 
  tran- 
  

   sitional 
  points, 
  §28, 
  can 
  already 
  be 
  pretty 
  well 
  predicted. 
  It 
  

   is 
  then 
  only 
  necessary 
  to 
  examine 
  a 
  number 
  of 
  substances, 
  

   normally 
  existing 
  under 
  widely 
  different 
  conditions 
  of 
  thermal 
  

   state, 
  J 
  in 
  order 
  to 
  broaden 
  the 
  evidence 
  and 
  possibly 
  to 
  reach 
  

   results 
  of 
  a 
  uniform 
  bearing 
  on 
  matter 
  in 
  general. 
  Thus 
  I 
  

   endeavor 
  to 
  avail 
  myself 
  of 
  the 
  enormous 
  internal 
  pressure 
  

   through 
  incremental 
  pressures 
  applied 
  externally. 
  

  

  Apparatus. 
  

  

  4. 
  Temperature. 
  — 
  Inasmuch 
  as 
  pressure 
  varies 
  at 
  a 
  mean 
  

   rate 
  of 
  over 
  30 
  atm. 
  per 
  degree 
  of 
  melting 
  point, 
  so 
  that 
  tem- 
  

   perature 
  is 
  as 
  it 
  were 
  the 
  coarse 
  adjustment 
  and 
  pressure, 
  the 
  

   fine 
  adjustment 
  for 
  the 
  conditions 
  of 
  fusion, 
  the 
  method 
  of 
  

   experiment 
  should 
  be 
  such 
  that 
  temperature 
  may 
  be 
  kept 
  rig- 
  

   orously 
  constant 
  while 
  pressure 
  is 
  varied 
  at 
  pleasure. 
  To 
  

   obtain 
  constant 
  temperature, 
  I 
  constructed 
  a 
  series 
  of 
  brazed 
  

  

  * 
  Kopp; 
  Ann. 
  Chem. 
  u. 
  Pharm., 
  xciii, 
  p. 
  129, 
  1855. 
  The 
  results 
  of 
  this 
  fine 
  

   memoir 
  are 
  too 
  rarely 
  quoted. 
  

  

  f 
  The 
  absolute 
  expansion 
  aud 
  compressibility 
  of 
  mercury 
  being 
  now 
  known. 
  

  

  §?• 
  

  

  % 
  "Instead 
  of 
  tracing 
  the 
  isothermals 
  of 
  a 
  single 
  substance 
  throughout 
  enormous 
  

   ranges 
  of 
  pressure, 
  similarly 
  comparable 
  results 
  may 
  possibly 
  be 
  obtained 
  by 
  ex- 
  

   amining 
  different 
  substances 
  conceived 
  to 
  exist 
  in 
  widely 
  different 
  thermal 
  states." 
  

   This 
  Journal, 
  1. 
  c, 
  xxxix, 
  p. 
  510. 
  

  

  Am. 
  Jour. 
  Sci. 
  — 
  Third 
  Series, 
  Vol. 
  XLII, 
  No. 
  248.— 
  August. 
  1891. 
  

   9 
  

  

  