﻿340 
  Scientific 
  Intelligence. 
  

  

  3. 
  On 
  Sulphuryl 
  Peroxide. 
  — 
  By 
  the 
  action 
  of 
  the 
  silent 
  electric 
  

   discharge 
  upon 
  a 
  mixture 
  of 
  either 
  sulphuric 
  oxide 
  or 
  sulphurous 
  

   oxide 
  and 
  oxygen, 
  Berthelot 
  obtained 
  several 
  years 
  ago 
  a 
  crystal- 
  

   lized 
  compound 
  tc 
  which 
  he 
  gave 
  the 
  name 
  persulphuric 
  acid 
  and 
  

   the 
  formula 
  S 
  2 
  7 
  . 
  The 
  same 
  substance 
  was 
  also 
  obtained 
  by 
  

   Berthelot 
  by 
  the 
  electrolysis 
  of 
  a 
  40 
  per 
  cent 
  sulphuric 
  acid. 
  

   Shortly 
  afterward 
  Traube 
  made 
  a 
  preliminary 
  examination 
  of 
  

   this 
  compound 
  and 
  concluded 
  that 
  its 
  formula 
  was 
  S0 
  4 
  and 
  not 
  

   S 
  2 
  7 
  ; 
  and 
  further 
  that 
  it 
  was 
  not 
  an 
  acid 
  oxide 
  as 
  Berthelot 
  sup- 
  

   posed, 
  but 
  a 
  neutral 
  substance, 
  sulphuryl 
  peroxide. 
  The 
  present 
  

   paper 
  deals 
  with 
  the 
  analytical 
  results 
  of 
  his 
  investigation. 
  Al- 
  

   though 
  he 
  has 
  not 
  succeeded 
  in 
  isolating 
  the 
  peroxide, 
  he 
  has 
  

   obtained 
  it 
  free 
  from 
  the 
  40 
  per 
  cent 
  sulphuric 
  acid 
  in 
  which 
  it 
  

   was 
  dissolved. 
  This 
  was 
  done 
  by 
  diluting 
  the 
  solution 
  with 
  2 
  to 
  

   4 
  times 
  its 
  volume 
  of 
  water 
  and 
  adding 
  to 
  it 
  freshly 
  prepared 
  

   barium 
  phosphate. 
  The 
  sulphuric 
  acid 
  is 
  thrown 
  down 
  as 
  barium 
  

   sulphate 
  and 
  the 
  filtrate 
  contains 
  the 
  peroxide 
  dissolved 
  in 
  phos- 
  

   phoric 
  acid 
  with 
  some 
  barium 
  phosphate. 
  It 
  does 
  not 
  seem 
  capa- 
  

   ble 
  of 
  existing 
  in 
  solution 
  in 
  pure 
  water. 
  As 
  the 
  peroxide 
  easily 
  

   evolves 
  oxygen 
  and 
  is 
  reduced 
  to 
  sulphuric 
  oxide, 
  the 
  composition 
  

   of 
  the 
  dissolved 
  compound 
  w 
  T 
  as 
  ascertained 
  by 
  taking 
  a 
  known 
  vol- 
  

   ume 
  of 
  the 
  solution, 
  determining 
  first 
  the 
  active 
  oxygen 
  therein 
  by 
  

   a 
  known 
  solution 
  of 
  ferrous 
  sulphate, 
  titering 
  back 
  with 
  perman- 
  

   ganate, 
  and 
  then 
  the 
  sulphuric 
  acid 
  as 
  barium 
  sulphate. 
  In 
  two 
  

   experiments, 
  the 
  active 
  oxygen 
  was 
  found 
  to 
  be 
  9*62 
  and 
  35 
  96 
  

   milligrams, 
  the 
  S0 
  3 
  present 
  being 
  49 
  5 
  and 
  178 
  '5 
  ; 
  giving 
  the 
  ratio 
  

   1:5-1 
  and 
  1 
  : 
  5 
  in 
  the 
  two 
  cases. 
  Hence 
  16 
  parts 
  active 
  ox} 
  T 
  gen 
  

   are 
  combined 
  with 
  80 
  parts 
  of 
  S0 
  3 
  ; 
  i. 
  e., 
  S0 
  3 
  + 
  = 
  S0 
  4 
  ; 
  or 
  per- 
  

   haps 
  (S0 
  3 
  ) 
  + 
  2 
  = 
  S 
  2 
  8 
  . 
  In 
  order 
  to 
  determine 
  its 
  neutral 
  char- 
  

   acter, 
  the 
  electrolyzed 
  sulphuric 
  acid 
  after 
  dilution 
  with 
  one 
  to 
  

   two 
  parts 
  of 
  water 
  and 
  cooling 
  to 
  —10°, 
  was 
  saturated 
  with 
  dilute 
  

   alkali 
  ; 
  a 
  process 
  which 
  did 
  not 
  affect 
  the 
  S0 
  4 
  . 
  On 
  boiling 
  the 
  

   neutral 
  solution 
  thus 
  obtained 
  for 
  a 
  half 
  hour, 
  until 
  a 
  drop 
  gave 
  

   no 
  blue 
  coloration 
  with 
  zinc-iodide-starch 
  solution, 
  the 
  active 
  

   oxygen 
  was 
  expelled 
  and 
  the 
  solution 
  became 
  intensely 
  acid. 
  

   Evidently 
  if 
  the 
  peroxide 
  had 
  been 
  an 
  acid 
  oxide 
  and 
  had 
  formed 
  

   an 
  acid 
  with 
  the 
  water 
  present, 
  a 
  salt 
  K 
  2 
  S0 
  5 
  would 
  have 
  resulted 
  

   from 
  the 
  saturation 
  of 
  this 
  acid 
  by 
  potassium 
  hydroxide. 
  And 
  

   this 
  on 
  giving 
  up 
  oxygen 
  would 
  have 
  produced 
  K 
  2 
  S0 
  4 
  still 
  neu- 
  

   tral. 
  This 
  evidence 
  of 
  neutrality 
  on 
  the 
  part 
  of 
  the 
  peroxide 
  was 
  

   confirmed 
  by 
  quantitative 
  data. 
  The 
  ratio 
  of 
  the 
  active 
  oxygen 
  

   in 
  the 
  solution 
  before 
  boiling 
  to 
  the 
  sulphuric 
  acid 
  produced 
  by 
  

   the 
  boiling 
  was 
  determined 
  ; 
  the 
  acid 
  by 
  titration 
  with 
  sodium 
  or 
  

   potassium 
  hydroxide, 
  using 
  rosolic 
  acid 
  as 
  an 
  indicator 
  ; 
  and 
  the 
  

   active 
  oxygen 
  either 
  by 
  ferrous 
  solution 
  and 
  permanganate 
  or 
  by 
  

   potassium 
  iodide 
  and 
  sodium 
  thiosulphate. 
  The 
  ratio 
  varied 
  from 
  

   I 
  : 
  4-56 
  to 
  1 
  : 
  5*10 
  ; 
  giving 
  1 
  : 
  4*85 
  as 
  a 
  mean. 
  The 
  active 
  ox} 
  r 
  gen 
  

   as 
  determined 
  by 
  the 
  iron 
  method 
  was 
  somewhat 
  higher 
  than 
  that 
  

   given 
  by 
  the 
  iodine 
  method, 
  owing 
  to 
  the 
  presence 
  of 
  acid 
  car- 
  

   bonate 
  of 
  the 
  alkali 
  in 
  the 
  solution, 
  which 
  decreased 
  the 
  free 
  acid 
  

  

  