218 



METALS. 



Composition: molybdenum 59*0, sulphur 41*0. Infusible 

 before the blowpipe, but when heated on charcoai, sulphur 

 fumes are given off, which are deposited on the coal. Dis- 

 solves in nitric acid, excepting a gray residue. 



Dif. Resembles graphite, but differs in its paler coloi 

 and streak, and also in giving fumes of sulphur when heated, 

 as well as by its solubility in nitric acid. 



Ohs. Occurs in granite, gneiss, mica slate, and allied 

 rocks ; also in granular limestone. It is found at Numedahl 

 in Sweden, Arendal in Norway, in Saxony, Bohemia, at 

 Caldbeck Fell in Cumberland, and in the Cornish mines. 



In the United States, it occurs in Maine at Blue Hill 

 Bay, Camdage farm, Brunswick, and Bowdoinham ; in New 

 Hampshire at Westmoreland, Landaff, and Franconia ; in 

 Massachusetts at Shutesbury and Brimfield ; in Connecticut 

 at Haddam and Saybrook ; in New York, near Warwick ; in 

 New Jersey, near the Franklin furnace. 



Molydic ocher. An earthy yellow or whitish oxyd of molybdenum, 

 (or rather molybdic acid,) occurring only as an incrustation. Occurs 

 at Westmoreland, N. H. 



For molybdate of lead, see under Lead. 



7. TUNGSTEN. 



Tungsten is found in combination with iron, lead, and lime, 

 constituting wolfram, (p. 244,) tungstate of lead, (p. 283,) 

 and tungstate of lime. It also occurs sparingly in some ores 

 of columbium, as in certain varieties of the minerals pyro- 

 chlore, columbite, and yttro-columbite. It is met with in 

 very sma.ll quantities as an ocher, or as tungstic acid, form, 

 ing a yellow powder on other tungsten ores. 



Lane's mine, Monroe, Conn., the adjoining town of Hunt- 

 ington, and Camdage farm, Blue Hill Bay, Me., are the only 

 American localities of tungsten ores yet discovered. Lane's 

 mine affords wolfram and the calcareous tungsten, and also 

 the tungstic ocher. These ores are frequent associates of 

 tin ore. 



No use in the arts has been made of this metal or its com- 



What is its composition ? How does it differ from graphite ? What 

 are the principal ores of tungsten? Has any use been made of them in 

 the arts ? 



