128 PROCEEDINGS OF THE AMERICAN ACADEMY 



bonate did not differ in outward appearance from the salt made directly 

 from mucobromic acid by the action of baric hydrate, but proved on 

 analysis to contain a percentage of barium materially lower than that 

 which O. R. Jackson and I had previously obtained, and closely agree- 

 ing with that required by one molecule of water of crystallization. 

 When dried by exposure to the air the salt lost nothing over sulphuric 

 acid or when heated to 85°, but by long-continued heat at 100° (75 to 

 100 hours) or more rapidly at 120° it gave up its crystal water with- 

 out showing any signs of decomposition. 



I. 0.6642 grm. of the air-dried salt gave by precipitation 0.2540 

 grm. BaSO^ . 

 II. 0.6392 grm. of the air-dried salt gave on ignition with H^SO^ 

 0.2434 grm. BaSO, . 

 III. 0.5300 grm. of the air-dried salt lost at 120° 0.0161 grm. H,0. 

 IV. 1.9253 grm. of the air-dried salt lost at 100° 0.0548 grm. HgO. 

 V. 1.1582 grm. of the air-dried salt lost at 100° 0.0351 grm. H^, 

 and gave by precipitation with HaSO^ 0.4408 grm. BaSO^ . 



Calculated for Ba(C3HBroOo)2 • H^O. Found. 



I. IT. III. IV. V. 



Ba 22.35 22.48 22.39 22.38 



HgO 2.94 3.04 2.85 3.03 



The solubility of the salt was also determined. 

 I. 9.4276 grm. of an aqueous solution saturated at 18° gave by 

 precipitation 0.2214 grm. BaSO^ . 

 II. 8.4088 grm. of a solution saturated at 18° gave 0.1917 grm. 

 BaSO, . 



According to these determinations the aqueous solution of the salt 

 saturated at 18° contains the following percentages of the anhydrous 



salt : — 



I. II. 



6.00 5.82 



Plumbic Dihromacrylafe, Pb(C3HBr202)2 ■ H.20- The lead salt 

 which, according to the analyses made of former preparations, was 

 anhydious when made from the pure acid by neutralization with plum- 

 bic carbonate, or from the acid potassium salt by precipitation with 

 plumbic acetate, likewise proved to contain one molecule of water of 

 crystallization. 



