Earths and Clays. 263 



Italian white chalk. Gesso, Bianchetto di pittorL Dull 

 white, hard, compact, regular texture, colouring, burns rather 

 harder ; used for a crayon. 



Blanc de Bougival. White marie, composed of two parts 

 clay and one of chalk, made up in oblong cakes. 



Blanc de Rouen. White marie, made up in masses of lib. 

 each. 



Blanc de Moudon, Blanc de Morat, Gera Earth 9 Silvery, 

 silky, white, very tine, effervescing with acids ; used as whiting. 



Strigau earth, Bole, Terra siglllata Silesiaca, Axungia soils. 

 Deep dull yellow, smooth, coarse but compact, heavy not colour- 

 ing, bums very hard, and to a fine red. From Strigau; astrin- 

 gent and alexiterial. 



Yellow ochre, French ochre. Spruce ochre. Powder ochre. 

 Light ochre, Sphragis. Fine dusky yellow, compact, firm, smooth, 

 unctuous, slightly colouring, when moist very viscid, burns very 

 hard, and to a fine bright red 5 Shotover Hill, Oxfordshire, and 

 elsewhere : used in painting. 



Light red rouge de Prusse. Light ochre burnt : produces 

 flesh colour with white lead and nut oil. 



Venice Tripoli, Terra Tripolitana vera. Whitish yellow, 

 or pale straw, firm, harsh, dry, colouring, bums rather harder 

 and to a pale rose colour ; used for polishing and cleaning metals. 



Tripoli. The septaria?, ludi Helmonti, or waxen veins, 

 found on the east coasts of England calcined. 



2. The clunch, or curl stone, of the Staffordshire mines cal- 

 cined : gives gold and silver a beautiful black lustre. 



Clay ochre, Stone ochre. Deep yellow, heavy, close, firm, 

 smooth, not colouring, burns to a fine deep colour, without any 

 hardness. From Alendip hills ; used in painting. — Burnt stone 

 ochre. Deep red. 



Yellow earth, Argilla lutea. Pale yellow, very fine, loose, 

 friable, colouring greatly, astringent taste, burns to a fine rose 

 colour, but not harder. From Saxony : used for polishing, and 

 as a paint. — Burnt yellow earth, Englischer rod. Fine rose red ; 

 used in Holland as a paint. 



Italian ochre, Jaune d^Itulie. Fine yellow, firm, compact, 

 very light, colouring, astringent; burns very hard, and to a dull 

 red. 



Coarse ochre. Fine bright, yellow, heavy, hard, firm, irre- 

 gular texture, harsh, dusty, ajlouring, very impure ; burns to a 

 very pale ashen red, but no harder : Mendip hills. 



