
PRODUCTS OF DECOMPOSITION OF COMENIC ACID. 237 
The per-centage calculated from these numbers are, 
I. II. Mean. 
4-29 4-66 4-44 
the mean of which agrees well enough with the number 4°33, corresponding to 
the formula 
2 (AgO, HO, C,, HCl O,)+3 aq. 
Neutral Chlorocomenate of Silver.—This salt is obtained in the form of a yellow, 
fiocky, amorphous substance, on the addition of a solution of the acid in a slight 
excess of ammonia to nitrate of silver. It is insoluble in boiling water, and 
acquires, in the process of drying, the consistence and adhesiveness of clay, which 
it also closely resembles in appearance. 
Considerable difficulty was experienced in the analysis of the salt; since, for 
the reason mentioned with regard to the acid salt, it cannot be burned, and it is, 
moreover, insoluble in water. When boiled with hydrochloric acid, a part of it 
escapes decomposition ; and if the attempt be made to dissolve it by aid of nitric 
acid, and precipitate the silver by hydrochloric acid, care must be taken to prevent 
the formation of cyanide of silver, which readily takes place when either of the 
silver salts is kept warm with even dilute nitric acid. The number I obtained 
was by carefully employing this process, and, though not accurate, comes suffi- 
ciently near to prove the composition of the salt. 
eee grains dried at 212° gave 
5457 ~~... chloride of silver. 
The per-centage of oxide of silver calculated from this is 56°85, and 57-37 is that 
corresponding to the formula 
2 Ag0, Cy, {a } 0,. 
The other salts of chlorocomenic acid, as might be anticipated, present close 
analogies with those of comenic acid; the former are generally more soluble than 
the latter. I have been unable to prepare neutral salts of the alkalies. 
The acid salts of potass, soda, and ammonia, crystallize readily ; a solution of 
the latter salt gives, with chlorides of calcium and barium, radiated groups of 
needles, appearing more or less quickly according to the state of concentration of 
the fluids; with sulphate of magnesia, a few crystals after some time; with 
‘sulphate of copper, a rapidly-appearing crystalline salt. The neutral salts of these 
bases appear to be insoluble amorphous substances generally. 
Action of Bromine on Comenic Acid. 
Bromocomenic Acid.—As might be expected, the behaviour of comenic acid 
towards bromine is closely similar to that which it exhibits when submitted to 
the influence of chlorine. It dissolves readily in aqueous bromine, yielding a 
colourless fluid if the bromine is not in great excess. In the course of a few hours 
VOL. XX. PART II. 38 
