486 M. H. Bleibtreu on Cumarine. 



crystallized from boiling water after distilling off the aether, 

 may be regarded as pure cumaric acid. 



With salts of sesquioxide of iron it now produces no colour 

 whatever, and possesses the following properties. It is rea- 

 dily soluble in alcohol and aether, and crystallizes from boil- 

 ing water in white brittle crystals. It possesses a decidedly 

 acid reaction, and expels carbonic acid from its salts. Its 

 point of fusion is near 190° C. If more strongly heated, it is 

 partly decomposed into white shining crystals, which sub- 

 lime, and a brownish residue. 



The cumarate of ammonia is not precipitated by a salt of 

 baryta ; but a white powdery insoluble precipitate is obtained 

 by the addition of acetate of lead. 



A combustion with chromate of lead of cumaric acid dried 

 at 100° C. gave the following results : — 



0-3415 grm. of substance gave 0*8215 carbonic acid and 

 0-1532 water. 



In per-centage, — 



Carbon 65-61 



Hydrogen .... 4 - 98 



These numbers correspond exactly to the formula of De- 

 lalande for this acid, HO, C 18 H 7 5 . 



The following are the experimental and theoretical num- 

 bers : — 



Theory. Bleibtreu. Delalande, 



2050-00 100-00 



To control this formula I also analysed the same silver 

 salt as Delalande. It was obtained, as above stated, by dis- 

 solving cumaric acid in ammonia and precipitating with ni- 

 trate of silver. There appeared however to exist two com- 

 pounds of cumaric acid with oxide of silver ; for on precipi- 

 tating a solution of the acid in excess of ammonia a tlocculent 

 orange-yellow precipitate was obtained, whilst that from the 

 neutral salt was light yellow, almost white, quickly settling 

 to the bottom of the vessel. The two compounds are further 

 essentially distinguished by the orange-coloured substance 

 becoming quickly brown on exposure to the air, and being 

 immediately decomposed on heating to 100° C, whilst under 

 the same circumstances the lighter remains quite unchangedi 

 In the following analyses the latter compound was employed, 



I. 0*5850 grm. cumarate of silver gave 0*8580 carbonic acid 

 and 0*1392 water. 



