﻿136 
  C. 
  Barus 
  — 
  Continuity 
  of 
  Solid 
  and 
  Liquid. 
  

  

  Table 
  4. 
  — 
  Pressure 
  coefficients 
  of 
  concentrated 
  zinc 
  sulphate 
  solution. 
  

  

  e 
  

  

  Pressure. 
  

  

  fcxlO 
  6 
  

  

  6 
  Pressure. 
  

  

  &x!0 
  6 
  

  

  6 
  Pressure. 
  

  

  &xlO« 
  

  

  7° 
  

  

  119 
  ) 
  

   479 
  f 
  

   119 
  i 
  

   868 
  J 
  

  

  -43 
  

   -35 
  

  

  100° 
  157 
  ) 
  

  

  : 
  482 
  \ 
  

  

  157 
  / 
  

  

  ; 
  996 
  J" 
  

  

  -64 
  

   -49 
  

  

  100° 
  137 
  ) 
  

   1007 
  V 
  

   474 
  i 
  

   1475 
  f 
  

  

  -43 
  

   -35 
  

  

  The 
  mean 
  value 
  is 
  ~k— 
  — 
  45/10 
  6 
  , 
  being 
  negative, 
  inasmuch 
  as 
  

   the 
  resistance 
  is 
  here 
  decreased 
  by 
  pressure. 
  The 
  pressure 
  

   coefficient 
  is 
  nearly 
  independent 
  of 
  temperature, 
  and 
  decreases 
  

   somewhat 
  with 
  pressure. 
  The 
  results, 
  however, 
  are 
  not 
  quite 
  

   consistent, 
  and 
  a 
  detailed 
  construction 
  of 
  the 
  data 
  in 
  table 
  2 
  

   shows 
  a 
  difference 
  of 
  march 
  in 
  the 
  pressure 
  on 
  and 
  the 
  pres- 
  

   sure 
  off 
  movements. 
  I 
  have 
  yet 
  to 
  learn 
  whether 
  this 
  be 
  due 
  

   to 
  insufficiently 
  iixed 
  terminals, 
  or 
  to 
  polarization, 
  as 
  well 
  as 
  

   to 
  find 
  the 
  conditions 
  (change 
  of 
  concentration 
  or 
  of 
  the 
  solu- 
  

   tion) 
  under 
  which 
  the 
  pressure 
  coefficient 
  may 
  be 
  a 
  minimum. 
  

   As 
  the 
  results 
  stand 
  the 
  mean 
  value 
  is 
  probably 
  within 
  20 
  per 
  

   cent 
  of 
  the 
  truth, 
  and 
  hence 
  in 
  the 
  extreme 
  case 
  of 
  2000 
  atm., 
  

   the 
  uncertainty 
  of 
  the 
  pressure 
  coefficient 
  will 
  not 
  affect 
  the 
  

   volume 
  increments 
  more 
  than 
  2 
  per 
  cent. 
  

  

  In 
  an 
  earlier 
  paper,* 
  I 
  found 
  Jc=— 
  50/10 
  6 
  between 
  and 
  

   150 
  atm., 
  agreeing 
  substantially 
  with 
  table 
  4. 
  I 
  then 
  called 
  

   attention 
  to 
  the 
  strikingly 
  close 
  proximity 
  of 
  this 
  datum 
  to 
  the 
  

   corresponding 
  coefficient 
  for 
  mercury 
  k=— 
  30/10 
  6 
  . 
  The 
  pres- 
  

   sure 
  coefficient 
  is 
  of 
  considerable 
  interest, 
  inasmuch 
  as 
  it 
  indi- 
  

   cates 
  a 
  certain 
  relation 
  between 
  elasticity 
  and 
  the 
  chemical 
  

   equilibrium 
  of 
  the 
  solid 
  or 
  liquid 
  operated 
  onf 
  specially 
  for 
  

   zinc 
  sulphate, 
  it 
  may 
  be 
  noted 
  that 
  whereas 
  the 
  conductivity 
  

   of 
  a 
  nearly 
  concentrated 
  solution 
  (density 
  > 
  1*29) 
  decreases 
  on 
  

   further 
  concentration, 
  compression 
  (which 
  might 
  be 
  regarded 
  

   as 
  having 
  a 
  concentrative 
  effect 
  on 
  the 
  solution 
  between 
  the 
  

   terminals) 
  increases 
  the 
  conductivity. 
  

  

  Results 
  of 
  the 
  measurements. 
  

  

  15. 
  Arrangement 
  of 
  the 
  tables. 
  — 
  The 
  following 
  tables 
  5 
  to 
  

   10, 
  in 
  which 
  the 
  isothermals 
  of 
  naphthalene 
  are 
  fully 
  given, 
  

   are 
  constructed 
  as 
  follows 
  : 
  The 
  first 
  column 
  contains 
  the 
  time 
  

   in 
  minutes 
  at 
  which 
  the 
  observation 
  was 
  made, 
  the 
  initial 
  date 
  

   being 
  arbitrary. 
  The 
  (uncorrected) 
  resistance 
  as 
  actually 
  found 
  

   at 
  the 
  pressure 
  given, 
  is 
  shown 
  under 
  B 
  in 
  ohms. 
  To 
  this 
  the 
  

   correction 
  for 
  pressure 
  coefficient, 
  hp 
  per 
  unit 
  of 
  li, 
  is 
  to 
  be 
  

  

  * 
  This 
  Journal, 
  xl, 
  p. 
  219, 
  1890. 
  The 
  work 
  of 
  this 
  paper 
  was 
  done 
  some 
  two 
  

   years 
  prior 
  to 
  the 
  publication. 
  

  

  f 
  Phil. 
  Mag 
  , 
  V, 
  xxxi, 
  p. 
  24 
  et 
  seq., 
  1891. 
  

  

  