148 PHYSIOGRAPHY. CLASS II. 



hills in Scotland, in a vein traversing grey-wacke, accom- 

 panied with various other ores of lead. Under similar 

 circumstances they have been lately brought from Spain. 



4. Several species have been lately discovered, which 

 will probably require to be included in the genus Lead- 

 baryte, and of which we shall here give a short notice. 

 These are the Sulphate-carbonate^ the Cupreous Sulphato- 

 carbonate, and the Cupreous Sulphate of Lead, determined by 

 Mr BROOKE, the Horriblei of WERNER and KLAPROTH, 

 and another compound of oxide of lead and chloride of 

 lead, discovered by BERZELIUS, and described without 

 giving it a name. 



i. Sulphato-carlonate of Lead. 



BROOKE, Edin. Phil. Journ. Vol. III. p. 117. PHILL. 

 p. 341. 



Hemi-prismatic. The crystals are generally oblique 

 angular four-sided prisms, with curved faces, terminated 

 by two planes, set obliquely on the obtuse edges of the 

 prisms, but producing a horizontal edge with each other. 

 They admit of cleavage with great facility parallel to a 

 plane, which replaces obliquely their acute lateral edges. 

 There are two less perfect cleavages besides, intersecting 

 the former at angles of about 120 45' and 88 45'. The 

 inclination of the axis takes place in a plane perpendicular 

 to the perfect plane of cleavage, and the plane of inclina- 

 tion has traces of cleavage parallel to it. The laminae 

 resulting from cleavage are flexible, like prismatoidal 

 Gypsum-haloide. Lustre adamantine, inclining to resin- 

 ous, pearly upon the perfect face of cleavage. Colour, 

 greenish-white or yellowish-white, sometimes inclining to 

 grey. Streak white. Translucent. Sectile. Hardness 

 = 2-0.. .2-5. Sp. Gr. = 6-8.. .7'0, BROOKE. 



According to Mr BROOKE, it consists of 46-9 of carbonate 

 and 53-1 of sulphate of lead. The effervescence, while dis- 

 solving in nitric acid, is scarcely perceptible. It is found 

 in columnarly aggregated crystals at Leadhills in Scotland, 



