Crystalline Forms of Artificial Salts. 287 



Most of the crystals I have observed were macles as repre- 

 sented in the third figure. 



Sub'chromate of Potash. 



ra on m 107° 8' 



P 90 



<"! on ?' 120 50 



ti on in 130 10 



Primary form. — A right rhombic prism of 107° 8', in which 

 the ratio of one side of the base, to the lateral edge of the 

 prism, is nearly that of 5 to 2. 



Cleavage. — None very distinct. 



This is the yellow chromate of potash, which, from the re- 

 marks of Mr. Taffaert, in the Annaies de Chimie for 1823, ap- 

 pears to be a sub-chromate. 



Bi-chromate of Potash. 



i^ 



Primitive form. A doubly oblique prism, in which the in- 

 cidences of the base j), on the two lateral planes m, f, are, re- 

 VoL. XV. U 



