OF ARTS AND SCIENCES. 267 



formiate, which was identified by its characteristic behavior with 

 argentic nitrate and mercuric chloride. The decomposition of muco- 

 pheooxybromic acid by potassic hydrate may therefore be expressed 

 by the reaction : — 



CJI,(OC,H,) BrO^ + 11,0 = C3H,(OC,H,)BrO, + CH A- 



While dibromacrylic acid passes readily into brompropiolic and 

 malonic acids in an alkaline solution, phenoxybromacrylic acid is ap- 

 parently unaltered by aqueous potassic hydrate. Even after long 

 boiling in a concentrated solution (2:1) no potassic bromide is 

 formed. 



Phenoxybrommaleic Acid. 



On warming a solution of mucophenoxybromic acid with argentic 

 oxide, metallic silver is readily formed. If the solution is then heated 

 to boiling, and the silver precipitated by hydrochloric acid, the filtered 

 solution deposits on cooling phenoxybrommaleic acid in the form of fine 

 felted needles. Their melting-point, when taken in the ordinary way, 

 we found to be 103-104°; but when slowly heated, the melting-point 

 was materially lowered, probably through the formation of the anhy- 

 dride. From the analysis of substance which had been dried over 

 sulphuric acid, it would seem that here also a certain amount of the 

 anhydride was formed, and that in this respect its behavior is perfectly 

 analogous to that of dibrommaleic acid which is partially converted 

 into anhydride by drying, as one of us has shown : * — 



I. 0.1213 grm. of substance dried over H^SO^ gave on combustion 

 0.1935 grm. CO, and 0.0245 grm. H^O. 

 II. 0.2204 grm. of substance dried over HgSO^ gave 0.1494 grm. 



n. 



28.85 



Ratio of carbon to bromine atoms as found = 10 : 0.995. 



Argentic Phenoxyhrommaleate. Ag2C\(OC(;H^)BrO^. By the ad- 

 dition of argentic nitrate to an aqueous solution of the acid, the silver 

 salt is precipitated in the form of clustered rhombic plates, which may 



* These Troceedings, Vol. XVI. (n. s. VIII.) p. 178. 



