﻿242 
  

  

  MR 
  HENRY 
  HOW 
  ON 
  CERTAIN 
  SALTS 
  AND 
  

  

  Calculation. 
  

  

  

  I. 
  

  

  II. 
  

  

  

  

  

  Carbon, 
  . 
  

  

  46-00 
  

  

  46-32 
  

  

  46-45 
  

  

  C 
  12 
  

  

  72 
  

  

  Hydrogen, 
  

  

  3-37 
  

  

  3-41 
  

  

  3-22 
  

  

  H 
  5 
  

  

  5 
  

  

  Oxygen, 
  . 
  

  

  • 
  

  

  

  41-30 
  

  

  8 
  

  

  64 
  

  

  Nitrogen, 
  

  

  9-17 
  

  

  

  9-03 
  

  

  N 
  

  

  14 
  

  

  10000 
  100-00 
  155 
  

  

  It 
  is 
  obvious 
  that 
  this 
  substance 
  is 
  an 
  acid 
  amide, 
  analogous 
  to 
  oxamic 
  acid, 
  

   and 
  that 
  its 
  constitution 
  is 
  expressed 
  by 
  the 
  formula 
  of 
  acid 
  comenate 
  of 
  ammonia 
  

   minus 
  two 
  atoms 
  of 
  water 
  = 
  HO, 
  NH 
  2 
  C 
  12 
  H 
  2 
  7 
  .* 
  

  

  It 
  crystallizes 
  with 
  four 
  equivalents 
  of 
  water. 
  

  

  f 
  10-250 
  grains 
  air-dry 
  acid 
  lost 
  at 
  212° 
  

   { 
  1-955 
  ... 
  water. 
  

  

  f 
  7-810 
  grains 
  air-dry 
  acid 
  lost 
  at 
  212° 
  

   { 
  1-450 
  ... 
  water. 
  

  

  J- 
  II' 
  Mean. 
  

  

  Per-centage, 
  . 
  19-07 
  18-56 
  18-81 
  

  

  The 
  number 
  18*84 
  is 
  that 
  corresponding 
  to 
  the 
  formula 
  

  

  HO, 
  NH,C 
  12 
  H 
  2 
  7 
  + 
  4HO. 
  

  

  Comenic 
  acid, 
  as 
  obtained 
  above, 
  is 
  in 
  brilliant 
  scales, 
  very 
  slightly 
  soluble 
  

   in 
  cold 
  water 
  ; 
  the 
  crystals 
  effloresce, 
  and 
  partially 
  lose 
  their 
  lustre 
  in 
  a 
  dry 
  

   atmosphere. 
  It 
  is 
  soluble 
  in 
  boiling 
  spirit, 
  but 
  very 
  slightly 
  in 
  absolute 
  alcohol. 
  

   It 
  has 
  a 
  powerful 
  acid 
  reaction 
  ; 
  dissolves 
  readily 
  in 
  excess 
  of 
  alkalies 
  ; 
  also 
  with 
  

   extreme 
  facility 
  in 
  the 
  strong 
  mineral 
  acids. 
  From 
  a 
  solution 
  in 
  any 
  of 
  these, 
  

   ammonia, 
  added 
  in 
  quantity 
  not 
  quite 
  sufficient 
  to 
  neutralize 
  the 
  whole 
  of 
  the 
  

   solvent, 
  throws 
  down 
  a 
  granular 
  precipitate 
  of 
  the 
  ammonia 
  salt. 
  Its 
  aqueous 
  

   solution 
  imparts 
  to 
  salts 
  of 
  peroxide 
  of 
  iron 
  a 
  magnificent 
  and 
  deep 
  pure 
  purple 
  

   colour, 
  which 
  is 
  destroyed 
  by 
  a 
  few 
  drops 
  of 
  a 
  mineral 
  acid, 
  but 
  reappears 
  on 
  

   dilution 
  of 
  the 
  fluid 
  with 
  water. 
  It 
  is 
  decomposed 
  by 
  boiling 
  with 
  caustic 
  potass, 
  

   with 
  evolution 
  of 
  ammonia 
  and 
  production 
  of 
  comenic 
  acid. 
  

  

  It 
  forms 
  readily 
  crystallizable 
  salts 
  with 
  a 
  certain 
  proportion 
  of 
  ammonia, 
  

   potass, 
  and 
  soda 
  ; 
  these 
  have 
  an 
  acid 
  reaction. 
  The 
  acid 
  remains 
  completely 
  in 
  

   solution 
  in 
  a 
  small 
  quantity 
  of 
  water, 
  when 
  supersaturated 
  with 
  any 
  alkali 
  ; 
  if 
  

   ammonia 
  be 
  employed, 
  and 
  the 
  fluid 
  be 
  evaporated 
  to 
  dryness 
  at 
  212°, 
  the 
  salt 
  

   with 
  acid 
  reaction 
  remains. 
  

  

  It 
  dissolves 
  the 
  earthy 
  carbonates 
  with 
  effervescence, 
  when 
  heated 
  with 
  them 
  

   in 
  water 
  ; 
  if 
  the 
  acid 
  be 
  in 
  excess, 
  a 
  crystalline 
  salt, 
  with 
  an 
  acid 
  reaction, 
  is 
  

   obtained 
  ; 
  if 
  the 
  carbonate 
  predominate 
  in 
  quantity, 
  almost 
  the 
  whole 
  acid 
  remains 
  

   undissolved 
  as 
  some 
  basic 
  compound. 
  

  

  * 
  I 
  have 
  also 
  obtained 
  this 
  substance 
  from 
  meconate 
  of 
  ammonia 
  ; 
  the 
  details 
  of 
  my 
  experi- 
  

   ments 
  will 
  be 
  given 
  in 
  a 
  future 
  paper 
  on 
  the 
  subject 
  of 
  some 
  derivatives 
  of 
  meconic 
  acid. 
  

  

  

  