OF ARTS AND SCIENCES. 263 



not been able to obtain uniform results in our various preparations. 

 We have found it advantageous to use a large excess of potassic 

 phenylate, and to add also potassic hydrate in quantity sufficient to 

 neutralize the mucobromic acid taken. We usually have dissolved 

 25 grms. of crystallized phenol and 17.5 grms. of ordinary potassic 

 hydrate in 30 grms. of water, and after the solution is well cooled, have 

 added 20. grms. of mucobromic acid. After the lapse of a short time 

 small compact rhombic crystals uf the new potassium salt begin to 

 separate, and the reaction is oidiuarily completed in less than an hour. 

 The crystals shouhl then be collected at once, drained by the pump, 

 and washed with a little cold water. Hydrochloric acid added to an 

 aqueous solution of the salt then precipitates mucophenoxybromic 

 acid in clustered needles, which, when dried over sulphuric acid, gave 

 the following results : — 



o 



I. 0.2156 grm. substance gave on combustion 0.3486 grm. COj 

 and 0.0525 grm. Hp. 

 II, 0.2250 grm. substance gave 0.1 5G4 grm. AgBr. 

 III. 0.2168 grm. substance gave 0.1504 grm. AgBr. 



in. 



29.52 



When crystallized from hot water, mucophenoxybromic acid forms 

 small flat prisms concentrically grouped, which melt at 104-105°. 

 The acid is readily soluble in hot water, sparingly in cold; readily 

 soluble in alcohol or ether, soluble in hot benzol or chloroform, and 

 almost insoluble in carbonic disulphide or ligroin. An aqueous solu- 

 tion of the acid reduces silver oxide on warming, and gives with ferric 

 chloride a whitish precipitate. 



Potassic Mucophenoxyhromate. KC^H(OC^H5)BrO,. The salt ob- 

 tained by the action of potassic phenylate upon mucobromic acid was 

 recrystallized several times from warm water. It formed then oblique 

 tabular crystals quite soluble even in cold water. The salt is more 

 stable in aqueous solution than the corresponding mncobromate, and 

 yet suffers quite rapid decomposition at temperatures near 100^. The 

 salt dried by exposure to the air contains no water of crystallization, 



I. 0.4314 grm. of the salt gave on ignition with HgSO^ 0.1227 grm. 

 K,SO,. 



