OP ARTS AND SCIENCES. 207 



Calculated. Found (mean). 



C = 50.00 50.18 



H = 3.57 4.20 



N == 8.26 8.06 



S = 9.60 10.10 

 O = 28.57 

 100.00 

 This formula would naturally be resolved into the structural for- 



^^\ /COOII 



mula, 



'' "XNH, 



■2 



or diamido-sulphobenzide-dicai-bonic acid, the reaction being as fol- 

 lows : — 



an. 



/NH, 



/NIL / ' '\COOH 



2 an/ ' + H,so, = 2 H,o 4- SO2 ^^^„ 



' '\COOH ^ ' * \ /COOH 



' '\NH2 



The melting point of the acid is above 350°. It is easily soluble 

 in hot water, and on cooling separates out in groups of fern-shaped 

 crystals. It is much less soluble in alcohol and ether, their addition 

 to the aqueous solution causing the precipitation of the acid in a white, 

 flocculent mass; chloroform dissolves it with difficulty; while it is 

 almost entirely insolulde in carbon bisulphide and benzine. Sul- 

 phuric acid dissolves it easily, forming a compound which is pre- 

 cipitated on the addition of alcohol, and is extremely soluble in water. 

 This compound awaits farther investigation. In concentrated hydro- 

 chloric acid it is completely insoluble. It dissolves easily in warm 

 nitric acid, but cannot be precipitated by the addition of alcohol. 



The new compound exhibits strongly marked acid properties, and 

 dissolves easily in alkalies. The neutral solution in ammonia yields 

 on evaporation the ammonium salt, in handsome laminated crystals, 

 which are easily soluble. 



The potassium salt obtained in the same way consists of small, fine, 

 colorless needles. 



The lead salt is white, and nearly insoluble in water. 



