SULPHURET OF LEAD. 4S 



Fig. 10. Fig. II. Fig. U. 



Morrietown, St. Lawrence Co. Martiniburgh, Lewis Co. Morristown, St. Lawi«nc« Co. 



Maitinsburgh, Lewis Co. Martinsburgh, Lewis Co. 



Wurtzboro*, SuUivan Co. 



Lustre splendent to glimmering, and metallic ; sectile ; very easily frangible. 



Hardness 2.5 to 3. Specific gravity 7.532 to 7.652 {Thomson) ; 7.759 {Beudant). 



Fusible before the blowpipe, with the disengagement of fumes of sulphur. When heated 

 on charcoal, the metallic lead is obtained. 



Soluble in nitric acid, forming a white precipitate of sulphate of lead. When dissolved in 

 dilute nitric acid, with only a slight elevation of temperature, the solution produces a preci- 

 pitate of brilliant blades of metallic lead upon a clean plate of zinc ; but not upon a plate of 

 copper, unless it contains sulphuret of silver. 



Distinctive characters. From graphite and sulphuret of molybdenum it may be dis- 

 tinguished by its greater specific gravity ; while from sulphuret of zinc, which it sometimes 

 resembles, its metallic and shining streak will be sufficient to distinguish it. 



Composition. The constituents of this mineral when pure, are sulphur 13.34, lead 86.66, 

 in 100 parts; but it sometimes contains minute proportions of silver, antimony and iron. 



This mineral is found in various parts of the State, and sometimes in large quantities. The 

 localities will be noticed in the alphabetical order of the counties in which they occur. 



Columbia County. At the Ancram Lead Mine, as it is usually called, about four miles 

 southeast of the Ancram furnace, galena is found in a hill composed of slate and limestone. 

 Two or three veins may here be observed on the surface ; which, with their gangue, vary in 

 width from a foot to three or four feet. When they widen, as they sometimes do, the ore is 

 very sparingly disseminated in the calcareous spar and quartz, which constitute its principal 

 associates. The galena at this locality does not seem to form a true vein, but to be a collec- 

 tion of strings communicating with masses or beds of various dimensions. These strings are 

 parallel with the strata, and not at right angles to them, and the ore is not bounded by a re- 

 gular wall, but gradually loses itself in the accompanying rock. 



