168 PROCEEDINGS OF THE AMERICAN ACADEMY 



m. 



59.40 



The ^y-dibrompyromucic acid crystallizes from benzol in short 

 clustered jirisms, from water in voluminous feather-like forms. It 

 is readily soluble in ether or alcohol, quite readily soluble in boiling 

 benzol or chloroform, and but sparingly soluble in carbonic disulphide 

 or ligroin. It is rather sparingly soluble even in hot water, and still 

 less soluble in cold water. The solubility of the acid in water at 

 ordinary temperatures we determined by boiling the saturated solu- 

 tion with baric carbonate and precipitating with sulphuric acid the 

 barium dissolved. 



I. 53.3668 grm. of a solution saturated at 20° gave 0.0481 grm. 



BaSO,. 

 II. 50.6792 grm. of a solution saturated at 20° gave 0.0477 grm. 

 BaSO,. 



The aqueous solution saturated at 20° therefore contained the fol- 

 lowing percentages of the acid : — 



I. n. 



0.21 0.22 



Baric Py-Dihrompyromucate, Ba(C5HBr203)„ . 3 H.,0. -^ The barium 

 salt we made by precipitating with baric chloride a dilute ammoniacal 

 solution of the acid, and I'ecrystallizing from boiling water the salt 

 thus precipitated. It formed irregular radiating flattened needles 

 which effloresced over sulphuric acid, but which contained three mole- 

 cules of water when dried by exposure to the air. 



I. 1.6173 grm. of the air-dried salt lost at 150° 0.1226 grm. H^O. 



II. 1.1994 grm. of the air-dried salt lost at 130° 0.0847 grm. H.O. 



Calculated for Found. 



Ba(05HBr,03)2 . 3 HoO. I II. 



H,0 7.41 7.58 7.06 



I. 1.4947 grm. of the anhydrous salt gave on ignition with H.^SO^ 

 0.5197 grm. BaSO,. 

 11. 0.4555 grm. of the anhydrous salt gave on ignition with HjSO^ 

 0.1544 grm. BaSO,. 



