OF ARTS AND SCIENCES. 159 



original alkaline solution. It will be noticed that this substance is 

 isomeric with a product obtained by Limpricht by the action of 

 bromine upon pyromuoic acid under conditions which he was unable 

 to fix precisely. The higher melting-point, 84°, and the fact that it 

 was unaffected by an alcoholic solution of potassic hydrate at 180°, 

 establish with sufficient precision their essential difference. 



The higher boiling fractions from which this crystalline substance 

 had been separated as completely as possible gave, on analysis, a 

 percentage of bromine, which showed that they consisted mainly of 

 a tribromfurfuran. The difficulty of removing completely, by dis- 

 tillation or by freezing, the solid constituent, sufficiently explains the 

 low percentages of bromine we have obtained. 



I. 0.2312 grm. of substance (C) gave 0.4130 grm. AgBr. 

 II. 0.3253 grm. of substance (C) gave 0.5855 grm. AgBr. 



III. 0.2897 grm. of substance (G) gave 0.5246 grm. AgBr. 



IV. 0.2291 grm. of substance (G) gave 0.4130 grm. AgBr. 



Br 



This tribromfurfuran, when treated with bromine, gave off at ordi- 

 nary temperatures clouds of hydrobromic acid, so that the correspond- 

 ing addition product could not be prepared. We have also been 

 unable as yet to obtain any definite oxidation products containing four 

 carbon atoms. 



The formation of dibromfurfuran from pyromucic tetrabromide 

 evidently takes place according to the equation, 



CgH.BrPs = C.H^Br.p -f CO., + 2 HBr. 



The tribromfm-fm-an must, of necessity, be formed from the mono- 

 brompyromucic tetrabromide which the crude pyromucic tetrabromide 

 contains, — 



C.HjBrA = CJIBi-p + CO, + 2 HBr. 



/?8-Dir.ROMrYRO>rucic Acid. 



This acid is formed, as has already been explained, together with 

 the isomeric /Sy-dibrompyromucic acid, by the action of an alcoholic 

 solution of sodic hydrate upon pyromucic tetrabromide. It may, how- 



