OF ARTS AND SCIENCES. 211 



This dibrominethylpyromucic acid crystallizes in small oblique 

 tabular crystals, which melt at 175° with decomposition. It is 

 readily soluble iu alcohol, ether, or glacial acetic acid, is but spar- 

 ingly soluble in boiling benzol or chloroform, and almost insoluble 

 in carbonic disulphide or ligroin. In boiling toluol it is quite 

 readily soluble. 



Action of Water. 



On warming with water the acid is decomposed, hydrobromic 

 acid is formed, and the solution then contains an oxybrominethyl- 

 pyromucic acid. We prepared this acid first by treating with 

 water the product formed by the vapors of bromine upon methyl- 

 pyromucic acid, and separating it from the brommethylpyromucic 

 acid melting at 151° which accompanied it by washing the mixed 

 acids with benzol. The acid thus prepared from the crude material 

 was absolutely identical with that afterwards made from the pure 

 dibrommethylpyromucic acid. For analysis the substance was 

 crystallized from a mixture of benzol and alcohol. 



I. 0.1950 grm. substance gave 0.2333 grm. C0 2 and 0.0420 grm. 



H 2 0. 

 II. 0.1695 grm. substance gave 0.1445 grm. AgBr. 



Found. 



n. 



36.28 



The o>-oxy-£(?) -brommethylpyromucic acid is readily soluble in 

 alcohol and ether, very sparingly soluble in boiling carbonic disul- 

 phide, somewhat more readily soluble in boiling chloroform, from 

 which it separates on cooling in obliquely terminated prisms. It 

 is sparingly soluble in hot benzol, and almost insoluble in ligroin. 

 It is readily soluble in hot water, more sparingly in cold, and 

 separates from dilute aqueous solutions in large obliquely termi- 

 nated prisms, which contain one molecule of water. The crystals 

 effloresce slowly over sulphuric acid, or even in the air after months 

 of exposure, but we were unable to dehydrate them by heat without 

 bringing about slight decomposition. 



I. 0.4413 grm. of acid cr3 T stallized from water lost over sulphuric 



acid 0.0328 grm. H 2 0. 

 II. 0.2117 grm. of acid dried in desiccator over night gave 

 0.1681 grm. AgBr. 



