306 SALTS 



At the temperature of about 500 they part 

 with 6 atoms water, but still retain 2 atoms 

 which are disengaged in a red heat. 

 Chromate, Q t Chromatc of magnesia. This is a fine 

 transparent yellow coloured salt, which crystal- 

 lizes in flat rhomboids, the obtuse angles of 

 which are usually truncated. It is very soluble 

 in water ; its constituents are as follows : 



1 atom chromic acid 6*5 



1 atom magnesia 2-5 



2 atoms water 2-25 



11-25 



When this salt is exposed to a strong red heat 

 it is partially decomposed ; for it is no longer 

 completely soluble in water. 



Acetate, iQ. Acetate of magnesia. A neutral solution 

 of this salt was left in vacuo over sulphuric acid. 

 It gradually inspissated into a thick transparent 

 jelly, which was exposed for some time to the 

 heat of the sand bath. Being laid in a cool place 

 it became solid on the surface, but remained li- 

 quid below. Being stirred with a glass rod, the 

 whole concreted into a white opaque crystalline 

 looking mass, not unlike loaf sugar ; it did not 

 deliquesce, though left for a week in an open ves- 

 sel. The taste of this salt is hot and bitter ; at 

 first it gives a slight impression of acetic acid 

 which soon passes ofT^ leaving a very disagreeable 

 taste behind. 



