OF ARTS AND SCIENCES. 211 



Calculated for Found. 



Ba(C 4 UI5r,S0 4 ) 2 . H 2 0. I. II. 



H 2 2.35 2.49 2.54 



I. 0.3952 grm. of the salt dried at 135° gave 0.1238 grm. BaS0 4 . 



II. 0.3932 grm. of the salt dried at 135° gave 0.1223 grm. BaS0 4 . 



III. 0.4219 grm. of the salt dried at 125° gave 0.1320 grm. BaS0 4 . 



Calculated for 

 Ba(C 4 IIBr,S0 4 ) 2 . 



Ba 18.40 



Potassic aa-Dlbromfurfuran-fi-sulphonate, KC 4 IIBr 2 S0 4 . — The po- 

 tassium salt can readily be made by the action of bromine upon a 

 slightly alkaline solution of potassic /3-sulpho-S-brompyromucate. It 

 crystallizes in well-formed prisms which are anhydrous. 



I. 0.3725 grm. of the salt gave 0.4090 grm. AgBr, and 0.2540 grm. 

 BaS0 4 . 

 II. 0.3329 grm. of the salt gave 0.3649 grm. AgBr, and 0.2283 grm. 

 BaS0 4 . 



Calculated for Found. , 



KC 4 HBr,S0 4 . I. II. 



Br 46.49 46.73 46.66 



S0 3 23.25 '23.41 23.55 



Bromine in aqueous solution readily attacks the salts of the aa-di- 

 bromfurfuran-/3-sulphonic acid; so that, if an excess of bromine is 

 added to a salt of /3-sulpho-S-brompyromucic acid, only the products of 

 this second stage of the reaction are obtained. The oxidation goes on 

 slowly at ordinary temperatures, more rapidly on warming, and even 

 after treating for a long time at 100° with an excess of bromine no 

 appreciable amount of sulphuric acid is formed. The final product of 

 the reaction is an acid containing the sulpho-group, which we have 

 named, provisionally at least, sulphofumaric acid. The acid itself we 

 found to be extremely soluble in water, and upon evaporating the 

 aqueous solution in vacuo a viscous residue was obtained which did 

 not crystallize even after long standing. The barium, lead, and silver 

 salts of the acid were very sparingly soluble even in boiling water. 

 The calcium and potassium salts, on the other hand, were very soluble 

 even in cold water, and could not be obtained in crystalline form. As 

 might have been expected, the strontium salt proved to be more readily 

 soluble than the barium salt, but it did not crystallize well from water. 

 We also found it impossible to prepare an acid salt the properties of 

 which were more favorable to purification. We therefore prepared 

 and analyzed the barium and silver salts. 



