THE MICROSCOPE IN CHEMISTRY. 109 



silver. The ammonium compound after ignition leaves 

 only the platinum, which gives no precipitate with nitrate 

 of silver, while the potassium chloride yields a white pre- 

 cipitate of chloride of silver. 



Antimoniate of potash throws down from solutions of 

 soda and its neutral salts a white crystalline antimoniate 

 of soda, the forms of which vary according to the strength 

 of the solution ; generally they are rectangular plates and 

 octahedra. 



ACIDS. 



Sulphuric. In solutions acidulated with hydrochloric 

 or nitric acid, the chloride or nitrate of baryta produces 

 a white precipitate. Veratrin added to a drop of concen- 

 trated sulphuric acid produces a crimson solution, or de- 

 posit if evaporated. 



Citric. Heated with excess of hydrochloric acid elimi- 

 nates chlorine, which will dissolve gold leaf. A blood- 

 red color is produced when nitric acid or a nitrate is mixed 

 with a sulphuric acid solution of brucin. 



Hydrochloric. Xitrate of silver precipitates amorphous 

 chloride of silver; soluble in ammonia, but insoluble in 

 nitric and sulphuric acid. 



Oxalic. Xitrate of silver precipitates amorphous oxa- 

 late of silver ; soluble in nitric acid and also in solution 

 of ammonia. 



Hydrocyanic. Put a drop of acid solution in a watch- 

 glass, invert another over it containing a drop of solution 

 of nitrate of silver, and a crystalline film will form. A 

 solution of hydrocyanic acid treated with caustic potash 

 or soda and then with persulphate of iron yields Prussian 

 blue. 



Phosphoric. A mixture of sulphate of magnesia, chlo- 

 ride of ammonium, and free ammonia produces in solu- 

 tions of free phosphoric acid and alkaline phosphates 

 white feathery or stellate crystalline precipitate of ammo- 



