OF ARTS AND SCIENCES. 289 



The calcium salt of the acid is very soluble even in cold water, and 

 it was not obtained in a crystalline form. 



Action of Bromine. 



/3y-dichlor-8-sulphopyromucic acid and its salts are immediately 

 oxidized by bromine in aqueous solution, with the formation of car- 

 bonic dioxide, sulphuric acid, and dichlormaleic acid. Baric /?y-dichlor- 

 8-sulphopyromucate was suspended in water and a slight excess of 

 bromine added. Baric sulphate was at once thrown down, and from 

 the filtered solution dichlormaleic acid was obtained by extraction with 

 ether. From the acid the anhydride was made by sublimation and 

 its identity established through its melting point, 119-120°.* 



The formation of )8y-dichlor-8-nitropyromucic acid through the ac- 

 tion of fuming nitric acid has already been described by Hill and 

 Jackson. f 



/8-Sulpho-S-Chlorptromucic Acid. 



8-chlorpyromucic acid was slowly added to four times its weight of 

 fuming sulphuric acid (sp. gr. 1.95), and the solution allowed to stand 

 for ten or twelve hours. The formation of the sulphonic acid was 

 then complete, and on neutralizing the diluted solution with baric car- 

 bonate a barium salt was obtained which could easily be purified by 

 recrystallization from hot water. The free /S-sulpho-S-chlorpyromucic 

 acid crystallized in dendritic needles which under ordinary atmospheric 

 conditions are permanent in the air. 



Baric ^-Sulpho-Z-Chlorpyromucate, BaCsHClSOo . 5 HoO. 

 This salt is readily soluble in hot water, and but sparingly soluble 

 in cold water. It crystallizes in large radiating needles which are per- 

 manent in the air, but slowly loses four of its five molecules of water 

 over sulphuric acid. 

 I. 0.8535 grm. air-dried salt gave 0.4411 grm. BaS04. 

 II. 1.6218 grm. air-dried salt gave 0.8371 grm. BaSOi. 



III. 1.9648 grm. air-dried salt lost at 130° 0.3893 grm. HoO. 



IV. 0.9748 grm. air-dried salt lost at 150° 0.1927 grm. H.,0. 

 V. 1.9953 grm. air-dried salt lost at 140° 0.3936 grm. HgO. 



Calculated for Found. 



BaCsUClSOfl . 5 H.O. I. II UI. IV. V. 



Ba 30.34 30.38 30.35 



H2O 19.93 19.81 19.76 19.73 



* Ciamician and Silber, Berichte d. deutsch. chem. Gesellsch., xvi. 2396. 

 t These Proceedings, xxiv. 3G1. 



VOL. XXV. (N. S XVII.) 19 



