170 PROCEEDINGS OP THE AMERICAN ACADEMY 



Tlie solution saturated at 20° therefore contaiued the following 

 perceutages of the auhydrous salt : — 



I. II. 



1.16 1.15 



Argentic [iy-Dihrompyromucate, AgCgHBrgOg. — From an aqueous 

 solution of the acid argentic nitrate precipitates the silver salt in the 

 form of minute clustered needles, which dissolve without essential 

 decomposition on heating the solution. For analysis we prepared it 

 by precipitating with argentic nitrate a neutral solution of the acid in 

 dilute ammouic hydrate. 



0.2584 grm. of the salt gave on precipitation with HBr 0.1297 grm. 

 AgBr. 



Calculated for AgCjIIBroOs. Found. 



Ag 28.65 " 28.83 



Sodic ^y-Dihrompyromucate, NaC^HBrjOg. 2 HgO. — The sodium 

 salt we prepared by dissolving the acid in a solution of sodic car- 

 bonate and recrystallizing from water the salt thus obtained. It 

 formed fine silky needles, which were not very soluble in cold water. 

 The air-dried salt contained two molecules of water. 



I. 2.0032 grm. of the air-dried salt lost at 119° 0.2192 grm. H^O. 

 II. 1.7440 grm. of the air-dried salt lost at 119° 0.1925 grm. H^O. 



Calculated for Found. 



NaCsHBrjOa . 2 U,0. I. II. 



HgO 10.97 ' 10.94 11.04 



I. 0.6162 grm. of the anhydrous salt gave on ignition with IIsSO^ 

 0.1502 grm. Na^SO,. 

 II. 0.6275 grm. of the anhydrous salt gave on ignition with H^SO^ 

 0.1506 grm. Na^SO^. 



Calculated for Found. 



NaCsIIBroOj. I. II. 



Na 7.88 7.90 7.78 



Potassic Py-Dibrompyromucate, KC^HBr^Og. — The potassium salt 

 made by neutralizing the acid with potassic carbonate crj'stallized in 

 flat clustered prisms, which were not very soluble in cold water and 

 were anhydrous. 



I. 0.5082 grm. of the salt gave on ignition with HoSO^ 0.1390 grm. 

 K.,SO,. 



