

59 



slowly oxidizes and becomes brown ; the same change takes place 

 more rapidly when a solution of it, especially if neutral or alkaline, 

 is evaporated. A solution of the acid immediately reduces ammonio- 

 nitrate of silver, even in the cold ; with sulphate of copper and a 

 slight excess of potash it gives a yellowish-green solution, from which 

 suboxide of copper is precipitated on warming. The free acid, or its 

 ammonia-salt, gives a very intense blue coloration with perchloride 

 of iron. The colour thus produced is changed to blood-red (exactly 

 resembling the red produced by the sulphocyanates) by ammonia, 

 and is destroyed by strong acids, being restored by dilution with 

 water, or by neutralization by an alkali : like the colouring matter 

 obtained by Anderson by the action of sulphuric acid on opianic acid, 

 it is entirely removed from solution by alumina. 



We have not yet obtained any of the salts of the new acid in a state 

 fit for analysis, and prefer not to propose a name for it until its rela- 

 tionship to other bodies has been more thoroughly examined; its 

 formula, however, assigns to it a place in the following series 



C 7 H 6 O Oil of bitter almonds. 



C 7 H 6 O a Benzoicacid. 



C 7 H 6 O 3 Salicylic acid. 



C 7 H 6 O 4 New acid. 



C 7 H 6 5 Gallicacid. 



C 7 H 6 O 6 Tannoxylic acid (?). 



It is remarkable that salicylic and gallic acids both give colorations 

 with perchloride of iron much resembling that produced by the acid 

 C 7 H 6 4 . 



IV. Action of dilute Nitric Acid on Cotarnine. 



By gently heating cotarnine with very dilute nitric acid, we have 

 obtained nitrate of methylamine and a new acid, cotarnic acid, but 

 have not hitherto found out the conditions necessary for the certain 

 production of the latter substance. 



Cotarnic acid dissolves easily in water, giving a solution which 

 reacts strongly acid with litmus-paper ; it dissolves only sparingly in 

 alcohol, and is precipitated from its alcoholic solution by ether. Heated 

 with an excess of sodium, it gives no trace of cyanide, and therefore 

 contains no nitrogen. With perchloride of iron it gives no color- 

 ation ; with acetate of lead it gives a white precipitate insoluble in ex- 



