OF ARTS AND SCIENCES. 347 



cold water, more readily in hot, and separates from a hot concentrated 

 solution in long needles which on standing are converted into oblique 

 prisms which melt at 153-154°. 



0.2781 grm. substance dried over HoSO^ gave 20.0 c.c. moist N at 

 25.0° under a pressure of 766 m.m. 



Calculated for 



CjHCloO.NIIa. Found. 



N 7.78 8.06 



Although the melting point, the crystalline form, and the insolubility 

 of its calcium salt showed that this acid closely resembled the 138 

 dibrompyromucic acid, it was evidently necessary to establish the posi- 

 tion of the chlorine atoms by means of its oxidation products. 



Action of Bromine and Water. 



Hill and Sanger* found that the /3S dibrompyromucic acid was 

 readily attacked by aqueous bromine in the cold with the formation 

 of monobrommaleyl bromide. The /38 dichlorpyromucic acid is but 

 slowly attacked by aqueous bromine in the cold, and we therefore sus- 

 pended it in five times its weight of water, added at once somewhat 

 more than four atoms of bromine, heated until the oil which was first 

 formed had almost all disappeared, and evaporated the solution at a 

 gentle heat. The crystalline mass thus obtained was readily soluble 

 even in cold water, and very sparingly soluble even in hot chloroform 

 or benzol. The product was dissolved in cold water, filtered, and 

 evaporated nearly to dryness. The crystals which separated were 

 pressed dry with filter paper, washed carefully with hot benzol, and 

 recrystallized from a little hot water. The acid thus prepared crys- 

 tallized iu microscopic crystals, which melted at 189-1 90°,t and proved 

 on analysis to contain the percentage of chlorine required by mono- 

 chlorfumaric acid. 



0.1288 grm. substance dried over HgSO^ gave 0.1227 grm. AgCl. 



Calculated for 

 C4lI:,C104. Found. 



CI 23.59 23.55 



The oxidation with bromine and water therefore takes place in 

 accordance with the following equation : 



C5H2CI2O3 + 2Br, + 3H,0 = C,H„C10, + CO, + HCl + 4HBr. 



* These Proceeding's, xxi. 165. 



t Kauder (Journal fiir prakt. Chemie, [2], xxxi. 28) gives the melting point 

 as 191°. 



