OF ARTS AND SCIENCES. 193 



I. 1.0621 grm. of the salt gave 0.4745 grm. CO., and 0.0780 grm. 



H.,0. 

 II. 1.0363 grm. of the salt gave 0.4609 grra. CO2 and 0.0743 grm. 

 H,0. 



III. 0.6187 grm. gave, on ignition with H^SO^, 0.2415 grm. BaSO^ 



IV. 0.6180 grm. gave 0.2434 grm. BaSO^.' 

 V. 0.5785 grra. gave 0.2269 grm. BaSO^. 



VI. 0.3522 grm. gave 0.1381 grm. BaSO^. 



Calculated for Ba(C,HBrjOj)2. Found. 



I. n. m. rv. V. YL 



C 12.10 12.19 12.14 



H 0.34 0.82 0.80 



Ba 23.03 22.95 23.15 23.05 23.05 



Argentic Dihromacrylate, AgCgHBr,©.,. From the barium salt, or, 

 better, from a solution of the free acid, the silver salt was made by 

 the addition of argentic nitrate. It is precipitated in the form of fine, 

 felted needles, even from a dilute solution of the acid; it may be re- 

 crystallized from hot water without any essential decomposition, and 

 forms then long, flattened needles. The salt was dried over sulphuric 

 acid for analysis. 



I. 0.9755 grm. substance gave 0.3890 grm. of CO., and 0.0432 grm. 



of H,0. 

 n. 0.3200 grm. substance gave, by the method of Carius, 0.3545 

 grm. AgBr. 



III. 0.7148 grm. substance, precipitated with. HBr, gave 0.4005 grm. 



AgBr. 



IV. 0.3668 grm. gave, with HBr, 0.2056 grm. AgBr. 



IV. 



32.20 



Plumbic Dihromacrylate^ Pb(C3HBr.^O.,)2. The lead salt is precipi- 

 tated in pearly rhombic scales by the addition of plumbic acetate to a 

 solution of the free acid. It is readily soluble in hot water, sparingly 

 in cold. "When dried over sulphuric acid in vacuo, it gave : — 



VOL. XVI. (n. s. viii.) 18 



