ZINC. 



411 



eight inches in width, has a course NNE. and SbW., anil traverses a bed of serpentine forty 

 or fifty feet in width. 



SuLUVAN County. In the Shawangnnk xnountains, about two miles west of the village of 

 Wurtzboro', and three quarters of a mile from the Hudson and Delaware canal, there is an 

 interesting deposit of zinc blende, galena, copper pyrites, with occasional masses and crystals 

 of iron pyrites. The whole is found in the nullstone grit, of which the mountain is composed. 

 The zinc blende is both crystallized and massive. The crystals are small, black, and very per- 

 fect tetrahedrons, Fig. 486 ; and of the same 



Fig. 48C. 



Fig, 487. 



form with the solid angles replaced by tan- 

 gent planes. Fig. 487. The massive variety 

 is of various shades of brown, and is often 

 so intimately mixed with the galena that the 

 eye can scarcely determine the line of sepa- 

 ration. This circumstance has interfered 

 materially with the processes for the re- 

 duction of the lead ore. 



Ulster County. Zinc blende has been found in various parts of this county. The best 

 locality is probably that near the village of Ellenville, where it is associated with galena, for 

 which extensive mining operations have been carried on. The specimens have a brown colour, 

 are easily cleavable, and seem to be fragments of large crystals. The vein above mentioned 

 is in the millstone grit or sandstone of which the Shawangunk mountain is composed. 



Westchester County. Blende of a dark colour and high lustre, occurs in rountlcd masses, 

 with copper and iron pyrites, in the dolomitic limestone in Eastchestcr. 



OXIDE OF ZINC. OR CADMIA. 



In the chimneys of the iron furnaces at Ancram in Columbia county, and at Amenia in 

 Dutchess, where the liematitic ores arc employed, there is often formed a deposit made up of 

 layers of a yellowish or reddish colour, and having a stony hardness. The same substance 

 has been observed in some of the iron furnaces in France, and has been called Cadmium, or 

 Cadmia. When first obtained from the Ancram furnace, it was supposed to be a native pro- 

 duct, and described by Dr. Torrey as a new ore of zinc* It is now known, however, to 

 result from the minute proportion of sulphuret or oxide of zinc which these ores contain, and 

 which, being volatized by the heat, is again deposited in the form of layers in the chimney of 

 ilie furnace. The following is the composilion of two specimens of cadmia from the Ancram 

 furnace, viz : 



' New-York Medical and PhysiCGl Journal. I. 191. 



