212 PROCEEDINGS OF THE AMERICAN ACADEMY 



Baric Sulphofumarate, Ba 3 (C 4 HS0 7 ) 2 • x H 2 0. — To an aqueous 

 solution of baric /3-suipho-S-brompyroniucate we added a slight excess 

 of bromine, and finished the reaction by the aid of heat. The strongly 

 acid solution thus obtained was partially neutralized by the addition 

 of baric carbonate, the carbonic dioxide expelled by long boiling, and 

 baric hydrate then added to alkaline reaction. In this way a volu- 

 minous flocculent precipitate was thrown down, which was dissolved 

 in boiling dilute hydrochloric acid and reprecipitated by amnionic 

 hydrate. Although the baric sulphofumarate was markedly soluble 

 in a solution of ammonic chloride, the analytical results were more 

 satisfactory than when the salt was again precipitated by baric hydrate. 

 The voluminous precipitate, when thoroughly washed and dried by 

 exposure to the air, formed a light, porous hygroscopic mass, which 

 gave us on analysis varying percentages. The salt dried at 130° gave, 

 however, a constant percentage of barium corresponding to that re- 

 quired by a salt with three molecules of water, and even at 200° one 

 molecule of water appeared to be retained. In each case, however, 

 the ratio between the barium and sulphur was found to be as 3 to 2. 



0.6486 grm. of the air-dried salt gave, after fusion with Na 2 C0 3 and 

 KC10 3 , 0.4918 grm. BaS0 4 (Ba) and 0.3310 grm. BaS0 4 (S0 3 ). 



Here it will be seen that the air-dried salt contained seven molecules 

 of water. This, however, must have been an accidental coincidence, 

 since the same salt after several days further exposure to the air, con- 

 tained more water. 



1.2865 grm. of the air-dried salt lost, at 200°, 0.1686 grm. H 2 0. 



6H 2 



0.5471 grm. of the salt dried at 200° gave 0.4706 grm. BaS0 4 (Ba), 

 and 0.3159 grm. BaS0 4 (S0 3 ). 



Found. 



50.56 

 19.82 



