﻿1875.] 
  

  

  Specific 
  Volumes 
  of 
  Liquids. 
  

  

  365 
  

  

  2S*6 
  and 
  12*2 
  ; 
  when 
  they 
  are 
  attached 
  by 
  only 
  one 
  combining 
  unit, 
  their 
  

   specific 
  volumes 
  are 
  22*6 
  and 
  7*8. 
  

  

  Phosphorus 
  is 
  regarded 
  by 
  certain 
  chemists 
  as 
  invariably 
  a 
  triad 
  ; 
  

   others 
  maintain 
  that 
  it 
  is 
  sometimes 
  a 
  triad, 
  at 
  other 
  times 
  a 
  pentad. 
  In 
  

   the 
  trichloride 
  it 
  is 
  a 
  triad, 
  in 
  the 
  oxychloride 
  and 
  thiochloride 
  it 
  is 
  a 
  

   pentad. 
  According 
  to 
  this 
  view, 
  the 
  two 
  latter 
  compounds 
  possess 
  the 
  

   following 
  constitution 
  :— 
  

  

  CI 
  CI 
  

  

  i 
  i 
  

  

  Cl— 
  P=0 
  C1-P=S 
  

  

  I 
  I 
  

  

  Cl 
  Cl 
  

  

  If, 
  however, 
  phosphorus 
  is 
  invariably 
  trivalent, 
  the 
  oxychloride 
  and 
  

   thiochloride 
  must 
  possess 
  the 
  formulae 
  

  

  Cl 
  Cl 
  

   I 
  I 
  

  

  P-O-Cl 
  P-S-Cl 
  

   I 
  ! 
  

  

  Cl 
  Cl 
  

  

  It 
  is 
  possible 
  to 
  decide 
  between 
  the 
  two 
  modes 
  of 
  representing 
  the 
  

   constitution 
  of 
  these 
  compounds, 
  if 
  it 
  be 
  granted 
  that 
  the 
  variation 
  in 
  the 
  

   specific 
  volume 
  of 
  oxygen 
  and 
  sulphur 
  is 
  due 
  to 
  the 
  manner 
  in 
  which 
  

   these 
  elements 
  are 
  held 
  in 
  union. 
  For, 
  if 
  the 
  phpsphorus 
  in 
  the 
  oxychlo- 
  

   ride 
  and 
  thiochloride 
  be 
  quinquivalent, 
  the 
  oxygen 
  and 
  sulphur 
  must 
  

   possess 
  the 
  greater 
  of 
  the 
  two 
  values, 
  since 
  both 
  their 
  combining 
  units 
  

   are 
  united 
  to 
  the 
  phosphorus 
  ; 
  if, 
  on 
  the 
  other 
  hand, 
  phosphorus 
  be 
  

   trivalent, 
  the 
  oxygen 
  and 
  sulphur 
  must 
  possess 
  the 
  smaller 
  of 
  the 
  two 
  

   values. 
  

  

  The 
  author 
  has 
  determined 
  the 
  specific 
  gravity, 
  boiling-point, 
  and 
  rate 
  

   of 
  expansion 
  of 
  P 
  Cl 
  3 
  , 
  P 
  Cl 
  3 
  , 
  and 
  P 
  S 
  Cl 
  3 
  , 
  in 
  order 
  to 
  ascertain 
  the 
  spe- 
  

   cific 
  volume 
  of 
  the 
  oxygen 
  and 
  sulphur 
  in 
  the 
  two 
  latter 
  compounds, 
  and 
  

   consequently 
  the 
  chemical 
  value 
  of 
  the 
  phosphorus 
  ; 
  and 
  he 
  finds 
  that 
  

   the 
  specific 
  volumes 
  of 
  the 
  oxygen 
  and 
  sulphur 
  are 
  almost 
  identical 
  with 
  

   the 
  values 
  given 
  by 
  Kopp 
  for 
  these 
  elements 
  when 
  " 
  without 
  the 
  radicle." 
  

   It 
  would 
  therefore 
  appear 
  that 
  the 
  oxychloride 
  and 
  thiochloride 
  must 
  

   possess 
  the 
  constitution 
  

  

  Cl 
  Cl 
  

   I 
  I 
  

   P-O-Cl 
  P-S-Cl 
  

  

  I 
  I 
  

  

  Cl 
  Cl 
  

  

  and 
  that 
  the 
  phosphorus 
  in 
  these 
  bodies 
  is 
  to 
  be 
  regarded 
  as 
  a 
  triad. 
  

  

  The 
  author 
  concludes 
  by 
  discussing 
  Buff's 
  hypothesis, 
  that 
  the 
  specific 
  

   volume 
  of 
  an 
  element 
  varies 
  with 
  its 
  chemical 
  value 
  ; 
  and 
  he 
  shows 
  that, 
  

   in 
  the 
  case 
  of 
  phosphorus, 
  there 
  are 
  no 
  reasons 
  for 
  the 
  belief 
  that 
  this 
  

   element 
  has 
  a 
  variable 
  specific 
  volume. 
  

  

  