382 ELEMENTARY CHEMICAL MICROSCOPY 



Large, colorless, well-formed, highly refractive crystals are 

 obtained. 



The solution to be tested must be concentrated, otherwise the 

 calcium tartrate will not separate save on long standing. Ex- 

 posure to alcohol vapors (Method VI, page 257) will hasten the 

 formation of a crystal deposit. 



Magnesium salts greatly retard the separation of crystals of 

 calcium tartrate. 



b. With Potassium Salts, tartrates yield characteristic color- 

 less, highly refractive, orthorhombic, short, stout prisms of the 

 primary salt KH^ILtOe. 



c. With Silver Nitrate. 



A granular precipitate only is obtained unless in very dilute 

 solution, then there will be obtained tiny squares and rectangles 

 and short, stout prisms giving a six-sided outline. 



Most other acids interfere with the detection of tartrates by 

 means of the silver salt. 



