﻿238 
  

  

  MR 
  HENRY 
  HOW 
  ON 
  CERTAIN 
  SALTS 
  AND 
  

  

  the 
  new 
  acid 
  is 
  deposited 
  in 
  fine, 
  square, 
  prismatic 
  crystals, 
  often 
  of 
  considerable 
  

   length, 
  and 
  presenting 
  a 
  very 
  beautiful 
  appearance, 
  from 
  their 
  high 
  refractive 
  

   power. 
  

  

  It 
  may 
  also 
  be 
  obtained 
  by 
  addition 
  of 
  bromine 
  water 
  to 
  solution 
  of 
  acid 
  

   comenate 
  of 
  ammonia, 
  but 
  I 
  found 
  it 
  more 
  convenient 
  to 
  employ 
  the 
  acid 
  itself. 
  

   I 
  may 
  mention 
  that 
  in 
  one 
  instance, 
  when 
  operating 
  upon 
  a 
  solution 
  of 
  the 
  am- 
  

   monia 
  salt, 
  a 
  considerable 
  excess 
  of 
  bromine 
  failed 
  to 
  yield 
  any 
  new 
  acid, 
  even 
  

   after 
  the 
  lapse 
  of 
  many 
  hours. 
  The 
  solution 
  remaining 
  colourless, 
  more 
  bromine 
  

   was 
  added, 
  and 
  as 
  no 
  crystals 
  appeared, 
  the 
  fluid 
  was 
  evaporated, 
  but 
  still 
  without 
  

   any 
  signs 
  of 
  bromocomenic 
  acid 
  ; 
  and 
  it 
  was 
  not 
  until 
  the 
  liquid 
  was 
  reduced 
  to 
  

   a 
  very 
  small 
  bulk, 
  that 
  any 
  substance 
  crystallized 
  out. 
  On 
  pouring 
  off 
  the 
  liquid, 
  

   which 
  had 
  now 
  become 
  nearly 
  black, 
  there 
  were 
  found 
  some 
  considerable-sized 
  

   transparent 
  crystals, 
  together 
  with 
  a 
  little 
  bromocomenic 
  acid 
  in 
  groups. 
  The 
  

   crystals 
  became 
  perfectly 
  colourless 
  on 
  washing 
  with 
  a 
  few 
  drops 
  of 
  water 
  ; 
  they 
  

   proved 
  to 
  be 
  oxalic 
  acid. 
  This 
  acid 
  always 
  appears 
  in 
  the 
  mother 
  liquors 
  from 
  

   which 
  chloro 
  and 
  bromo 
  comenic 
  acids 
  have 
  been 
  separated 
  by 
  evaporation, 
  result- 
  

   ing 
  probably 
  from 
  a 
  secondary 
  decomposition. 
  

  

  The 
  crystals, 
  as 
  obtained 
  by 
  the 
  action 
  of 
  bromine 
  water 
  upon 
  comenic 
  acid, 
  

   after 
  being 
  washed, 
  and 
  recrystallized 
  from 
  boiling 
  water, 
  gave 
  the 
  following 
  

   results 
  : 
  — 
  

  

  {6001 
  grains 
  dried 
  at 
  212° 
  Fahr. 
  gave 
  

   6*767 
  ... 
  carbonic 
  acid, 
  and 
  

   0-806 
  ... 
  water. 
  

  

  f 
  4-330 
  grains 
  dried 
  at 
  212° 
  gave, 
  when 
  burned 
  with 
  lime, 
  

   (3-475 
  ... 
  of 
  bromide 
  of 
  silver. 
  

  

  Carbon, 
  

   Hydrogen, 
  

   Oxygen, 
  . 
  

   Bromine, 
  . 
  

  

  Experiment. 
  

  

  30-75 
  

   1-49 
  

  

  34-15 
  

  

  Calculation. 
  

  

  30-63 
  

  

  1-27 
  

  

  34-06 
  

  

  34-04 
  

  

  H, 
  

  

  Br 
  

  

  72 
  

  

  3 
  

  

  80 
  

  

  80 
  

  

  100-00 
  100-00 
  235 
  

  

  which 
  shew 
  that 
  they 
  consist 
  of 
  an 
  acid 
  precisely 
  analogous 
  with 
  chlorocomenic 
  

   acid 
  ; 
  an 
  equivalent 
  of 
  bromine 
  taking 
  the 
  place 
  of 
  one 
  of 
  hydrogen 
  in 
  the 
  comenic 
  

   acid. 
  In 
  the 
  hydrated 
  state 
  it 
  contains, 
  like 
  the 
  chlorine 
  acid, 
  three 
  atoms 
  of 
  

   water. 
  

  

  f 
  11-14 
  grains 
  air-dry 
  acid 
  lost 
  at 
  212° 
  

   \ 
  1-15 
  ... 
  water, 
  

  

  which 
  corresponds 
  to 
  10-32 
  per 
  cent. 
  ; 
  1030 
  is 
  the 
  number 
  required 
  by 
  the 
  formula 
  

  

  2H0C 
  12 
  {^ 
  r 
  J0 
  8 
  + 
  3aq. 
  

  

  This 
  acid 
  so 
  closely 
  resembles 
  the 
  chlorocomenic 
  in 
  its 
  general 
  properties 
  and 
  

   products 
  of 
  decomposition, 
  that 
  a 
  very 
  few 
  words 
  will 
  suffice 
  to 
  describe 
  it. 
  It 
  is 
  

  

  