§ 5. HE A GENTS. 13 



precipitated chloride has acciiinulated, separate it from 

 the liquid by decantation of the latter, wash it well with 

 water, pour dilute sulphuric acid over it, and put some 

 pieces of zinc in contact witli it. 



When the whole is changed to a gray metallic powder, 

 and the zinc is all dissolved, filter out and wash the pow- 

 der well, dry, and ignite it. Dissolve the silver thus ob- 

 tained in nitric acid, add water, filter if necessary, evap- 

 orate the filtrate to dryness on the water-bath, and dis- 

 solve the residue in 20 parts of water, and subject the 

 solution to the tests above described. 



5. r^— Baric acetate. — Bii{CJIfi^)^. Acetate of 

 baryta. BaO,C,Il3()3. BaO,A.)— This should be colorless 

 and should have no empyreumatic odor, and it should 

 give no reaction with amnionic sulphide or argentic ni- 

 trate ; after complete precipitation with sulphuric acid, 

 the filtrate should leave no residue on evaporation. Dis- 

 solve in 10 parts of water. 



b. Baric chloride* — BaCl^. (Chloride of barium. BaCl.) 

 — This should not affect litmus-paper, nor give any 

 reaction with nmmonic sulphide ; after complete pre- 

 cipitation Avith sulphuric acid, the filtrate from the precipi- 

 tate should leave no residue when evaporated. Dissolve 

 in 10 parts of water. 



€. Baric liydrate. — Ba(IIO)„. (Hydrate of baryta. 

 Baryta water. BaO,HO.) — After precipitation of the 

 barium from the solution by sulphuric acid, the filtrate 

 should remain clear when mixed with alcohol, and should 

 leave no residue when evaporated. Dissolve in 20 parts 

 of water. In determinations of urea in urine, a mixture 

 of one volume of a cold saturated solution of baric nitrate 

 and two volumes of a cold saturated solution of baric 

 hydrate is vised. 



cl Baric nitrate.— Ba(N'03),. (titrate of baryta. BaO, 

 NO^.) — This should be completely precipitated by sul- 



