OF ARTS AND SCIENCES. 95 



on the water bath. Dibromiodacrylic acid was formed in small quan- 

 tity, when the solid residue left by evaporation of the excess of bro- 

 mine was dissolved in ether and allowed to stand with brompropiolic 

 acid. The product of this reaction, however, consisted to a large 

 extent of an oil, from which very little pure substance could be recov- 

 ered. This ditiiculty was partially overcome by the application of 

 heat ; and by boiling the solution for an hour on the water bath we 

 succeeded in obtaining about forty per cent of the amount theoretically 

 required. The thick pasty mass left after the evaporation of the ether 

 soon solidified, and was easily purified by crystallization from hot 

 water. 



Dibromiodacrylic acid dissolves readily in ether, alcohol, carbonic di- 

 sulphide, and chloroform. In cold water it is rather sparingly soluble ; 

 from a concentrated hot solution it falls at first as an oil, which crystal- 

 lizes as the solution cools, in oblique prisms of the monoclinic system. 

 It melts at 139°-140°, and sublimes slowly at higher temperatures. 



The composition of this substance was determined by the following 

 analyses : — 



I. 1.0762 grm. of the substance gave 0.3385 grm. CO^ and 0.0420 



grm. HgO. 

 II. 0.1993 grm. of the substance gave by the method of Carius 

 0.3385 grm. Ag Br + Ag I. 



To determine the solubility of this acid at ordinary temperatures, 

 we used the method of V. Meyer. The filtered solution was neutral- 

 ized with baric carbonate, and the barium estimated by precipitation 

 with sulphuric acid. 



I. 8.7164 grms. solution gave 0.0968 grm. BaSO^ . 

 II. 9.7772 grms. solution gave 0.1089 grm. BaSO^ . 



The solution saturated at 20° contains, therefore, the percentages : — 



I. IT. 



3.39 3.40 



Dr. "W. H. Melville has made a cry stall ographic examination of 

 this substance, and obtained the following results : — 



