186 PHYSIOGRAPHY. 



Oxide of Iron 8>00 3-00, 



Sulphuric Acid 3'50 0-00. 



Water 5-00 0-00., 



with a trace of Lime. It seems to be nothing but a very fine 



arenaceous variety of quartz, accidentally mixed with, a 



little clay. 



UMBER, 



Umber. JAM. Syst. Vol. III. p. 241. Umber. PHILL. 

 p. 232. 



Massive. Composition impalpable. Fracture large 

 and flat conchoidal in the great, very fine earthy 

 in the small. 



Dull. Colour liver-, chestnut-, dark yellowish- 

 brown. Acquires some lustre in the streak. 

 Opake. 



Imperfectly sectile. Does not soil, but writes, ad- 

 heres strongly to the tongue, feels a little rough 

 and meagre, and is very soft. Sp. Gr. ir: 2-206, 

 BREITHAUPT. 



It imbibes water with great avidity, and emits air bubbles, 

 but does not become soft. It occurs in beds with brown 

 jasper in the isle of Cyprus, and is used by painters as a 

 brown colour. Its chemical composition is said to be oxide 

 of iron 48, oxide of manganese 20, silex 13, alumina 5, 

 water 14. 



WHET-SLATE. 



Whet-Slate. JAM. Syst. Vol. II. p. 271. Whet-Slate or 

 Hone. Man. p. 343. Whetslate. Turkey Hone. 

 PHILL. p. 48. 



Massive. Composition impalpable, Fracture 



