13* § 4. IlEACjiEXTS. 



action at all with solutions of lime or maghesia ; when 

 evaporated in a platinum dish, the residue should be vola- 

 tilized completely on ignition. 



Dissolve some flowers of sulphur in a small j^ortion of 

 the reagent, and label this solution, ammonic sulphide 

 with excess of sulphur. 



I. Ammonic tartrate.— (NH J, CJip,. (Tartrate of 

 ammonia. 2X11^0,0311^0^^.) — Neutralize tartaric acid 

 with ammonic hydrate, and then add more ammonic hy- 

 drate, so that it shall be in excess over the acid. 



m. Ammonic-ferrous sulphate. — (NHJ^Fc (SOJ^. 

 (Sulphate of j^rotoxide of iron and ammonia. NH^O, 

 FeO, (SOg)^.) — ^Divide a quantity of sulphuric acid into 

 two equal j^arts ; heat one of them with an excess of 

 small clean iron nails free from rust, as long as the evolu- 

 tion of hydrogen continues. Neutralize the other portion 

 of the acid accurately with ammonic carbonate, and then 

 add a few drops of sulphuric acid. Filter the solution of 

 ferrous sulphate, obtained by the action of the acid on the 

 nails, into the ammonic sulphate, evaporate the mixture 

 a little if necessary, and let it crystallize. Let the crys- 

 tals drain in a funnel, dry them by exposure to the air ou 

 filter-paper, and keep them in a well stoppered bottle. 

 The solution of the salt in water acidified with sulpliuric 

 acid should give no red color with potassic sulphocyanate. 



4. Argentic nitrate. — AgNO^. (Nitrate of silver. 

 AgO, NO^.) — After the solution of this reagent has been 

 completely precipitated with hydrochloric acid, the fil- 

 trate from the precij)itate should leave no residue Avlien 

 evaporated, and the same filtrate should give no color 

 with ammonic sidphide. Dissolve in 20 parts of water. 



All the silver refuse, consisting of i:)recipitates contain- 

 ing silver, and solutions to which argentic nitrate has been 

 added, should be thrown into a bottle containino; dilute 

 hvdrocliloric acid. When a sufiicient quantity of the 



