﻿PRODUCTS 
  OF 
  DECOMPOSITION 
  OF 
  COMENIC 
  ACID. 
  243 
  

  

  A 
  solution 
  of 
  the 
  crystalline 
  ammonia 
  salt 
  gives, 
  with 
  nitrate 
  of 
  silver, 
  a 
  white 
  

   gelatinous 
  precipitate, 
  which 
  partially 
  decomposes 
  in 
  boiling 
  water. 
  The 
  same 
  

   solution 
  made 
  alkaline 
  gives, 
  with 
  nitrate 
  of 
  silver, 
  a 
  yellow 
  flocky 
  precipitate, 
  

   which 
  almost 
  instantly 
  passes 
  through 
  deepening 
  shades 
  of 
  colour 
  into 
  a 
  heavy, 
  

   black, 
  amorphous 
  precipitate. 
  The 
  same 
  solutions 
  give, 
  with 
  acetate 
  of 
  lead, 
  

   heavy 
  insoluble 
  precipitates 
  ; 
  the 
  acid 
  solution 
  gives, 
  with 
  sulphate 
  of 
  copper, 
  a 
  

   grey 
  precipitate. 
  

  

  I 
  have 
  examined 
  more 
  fully 
  and 
  analyzed 
  two 
  or 
  three 
  of 
  the 
  salts 
  of 
  come- 
  

   namic 
  acid. 
  

  

  Comenamate 
  of 
  Ammonia. 
  — 
  Comenamic 
  acid 
  dissolves 
  readily 
  in 
  ammonia, 
  

   when 
  the 
  alkali 
  is 
  added 
  in 
  excess, 
  and 
  such 
  a 
  fluid 
  deposits 
  no 
  salt 
  on 
  standing 
  ; 
  

   but 
  if 
  ammonia 
  be 
  added 
  to 
  a 
  boiling 
  aqueous 
  solution 
  of 
  the 
  acid, 
  in 
  such 
  quan- 
  

   tity 
  that 
  the 
  reaction 
  remains 
  slightly 
  acid, 
  the 
  ammonia 
  salt 
  crystallizes 
  out 
  on 
  

   cooling 
  of 
  the 
  fluid 
  in 
  small 
  grains, 
  which, 
  when 
  magnified, 
  are 
  found 
  to 
  consist 
  

   of 
  bundles 
  of 
  needles 
  radiating 
  from 
  a 
  centre. 
  They 
  are 
  difficult 
  of 
  solution 
  in 
  

   boiling 
  water, 
  but 
  do 
  not 
  always 
  reappear 
  quickly 
  when 
  the 
  liquid 
  is 
  cold. 
  Their 
  

   solution 
  shews 
  the 
  phenomenon 
  of 
  epipolic 
  dispersion 
  very 
  beautifully, 
  when 
  ren- 
  

   dered 
  alkaline 
  by 
  ammonia. 
  They 
  are 
  anhydrous. 
  

  

  ( 
  5-623 
  grains 
  dried 
  at 
  212° 
  gave 
  

   < 
  8-570 
  ... 
  carbonic 
  acid, 
  and 
  

   ( 
  2-446 
  ... 
  water. 
  

  

  f 
  4-945 
  grains 
  dried 
  at 
  212° 
  gave 
  

  

  \ 
  12-715 
  ... 
  platinum 
  salt 
  of 
  ammonia. 
  

  

  Carbon, 
  

   Hydrogen, 
  

   Oxygen, 
  

   Nitrogen, 
  

  

  Experiment. 
  

  

  

  Calculation. 
  

  

  

  41-56 
  

  

  41-86 
  

  

  Vl2 
  

  

  72 
  

  

  4-83 
  

  

  4-64 
  

  

  H 
  8 
  

  

  8 
  

  

  

  37-23 
  

  

  8 
  

  

  64 
  

  

  16-14 
  

  

  16-27 
  

  

  N 
  2 
  

  

  28 
  

  

  100-00 
  100-00 
  100 
  

  

  The 
  above 
  analysis 
  leads 
  to 
  the 
  formula 
  

  

  NH 
  4 
  O, 
  NH 
  2 
  C 
  12 
  H 
  2 
  7 
  . 
  

  

  Comenamate 
  of 
  Baryta. 
  — 
  The 
  salt 
  I 
  analyzed 
  was 
  obtained 
  by 
  adding 
  a 
  solu- 
  

   tion 
  of 
  the 
  ammonia 
  salt 
  to 
  chloride 
  of 
  barium 
  ; 
  a 
  precipitate 
  was 
  obtained 
  in 
  

   radiated 
  groups, 
  which, 
  on 
  crystallization 
  from 
  boiling 
  water, 
  assumed 
  the 
  form 
  

   of 
  separate 
  prisms. 
  It 
  had 
  an 
  acid 
  reaction. 
  

  

  {4-565 
  grains 
  dried 
  at 
  212° 
  gave 
  

   5-055 
  ... 
  carbonic 
  acid, 
  and 
  

   1-105 
  ... 
  water. 
  

  

  {t 
  

  

  4-425 
  grains 
  dried 
  at 
  212° 
  gave, 
  when 
  ignited 
  with 
  S0 
  3 
  

   190 
  ... 
  sulphate 
  of 
  baryta. 
  

  

  