OP ARTS AND SCIENCES. 203 



way long, slender prisms, extremely soluble in water, alcohol, or ether, 

 readily in chloroform or benzol, more sparingly in carbonic disulphide, 

 and but slightly soluble in ligroin. The crystals obtained from 

 aqueous solution by spontaneous evaporation appeared to contain 

 water of crystallization. When pressed with paper they melted at 

 60-65° ; but over sulphuric acid they soon became opaque, and the 

 melting point had risen to 80° or over. 



AVe attempted the purification of the acid by repeated recrystalliza- 

 tion from ligroin to which a little ether had been added. The long, 

 silky needles thus obtained melted at 86°, but gave on analysis no 

 satisfactory results (I. and II.). Although the acid was blackened 

 and apparently completely decomposed at a temperature but little 

 over 100°, we found that it could be sublimed readily between watch- 

 glasses at steam heat. The melting point was, however, lowered 

 rather than raised, by successive sublimations, and analyses (III. and 

 IV ^ of the sublimed product gave too high a percentage of bromine. 



I. 0.3010 grm, substance gave 0.4025 grm. AgBr. 



II. 0.1198 grm. substance gave 0.1582 grm. AgBr. 



III. 0.2010 grm. substance gave 0.2580 grm. AgBr. 



IV. 0.1820 grm. substance gave 0.2339 grm. AgBr. 



Calculated for CgHBrOj. 



Br 53.69 



The acid is decomposed, with the formation of carbonic dioxide and 

 bromacetylen, on boiling its aqueous solution. When heated with an 

 excess of baric hydrate, baric carbonate is precipitated, bromacetylen 

 is evolved, and at the same time baric malonate is formed in abun- 

 dance. It unites with dibromacrylic acid immediately to form the 

 characteristic addition-product. An ethereal solution containing a 

 mixture of the two acids, approximately in molecular pi'oportions, 

 gave on evaporation a substance which, without purification, melted at 

 103°. With the halogens and haloid acids, it forms addition-products 

 with the greatest readiness. The substituted acrylic acids which are 

 thus formed, according to the equations, — 



CgHBrO^ + HX = C5H2BrX02 

 C3HBr03 + X,=:C3HBrXA, 



are easily purified, and their formation can leave no doubt of the 

 nature of the brompropiolic acid. Several of these acids will be 

 described later in this paper. 



