176 PROCEEDINGS OF THE AMERICAN ACADEMY 



I. 0.6837 grm. substance gave 0.42GG grin. CO2 and 0.0221 grm. 



II. 0.1658 grm. substance gave 0.2684 grm. AgBr. 



III. 0.1885 grm. substance gave 0.30-17 grm. AgBr. 



III. 



68.79 



Tribrompyromucic acid crystallizes in minute clustered needles 

 which melt at 218-219°. It is readily soluble in alcohol or ether, 

 somewhat sjDaringly soluble in chloroform or benzol, and very sj^aringly 

 soluble in carbonic disulphide or ligroin. It dissolves with difficulty 

 even in boiling water, and the hot solution deposits the greater part of 

 the acid on cooling. In order to determine the solubility of the acid 

 in cold water, we boiled the saturated solution with baric carbonate 

 and precipitated with sulphuric acid the barium dissolved. 



I. 43.8259 grm. of a solution saturated at 19° gave 0.0105 grm. 



BaSO,. 

 II. 42.6017 grm. of a solution saturated at 19° gave 0.0101 grm. 

 BaSO,. 



According to these determinations the aqueous solution saturated at 

 19° contained the following percentages of the acid : — 

 I. n. 



0.072 0.071 



Banc Trihrompyromucate, Ba(C5Br303)2 . 3 11,0.— The barium salt 

 we prepared by precipitating a solution of baric chloride with a solu- 

 tion of the acid in dilute ammonic hydrate and recrystallizing from 

 boiling water the salt thus obtained. It crystallized in dendritic nee- 

 dles, which, when air-dried, contained three molecules of water, nearly 

 all of which it lost over sulphuric acid. 



I. 1.1629 grm. of the salt lost at 120° 0.0695 grm. H,0. 

 11. 1.6160 grm. of the salt lost at 120° 0.0970 grm. H^O. 



I. 0.6867 grm. of the anhydrous salt gave on ignition with H2SO4 

 0.1878 grm. BaSO^. 



