2S4 



METALS. 



angular. In the inner flame, gives off fumes of lead. WitK 

 boracic acid and iron, gives a phosphuret of iron and metallic 

 lead. 



Dif. Has some resemblance to beryl and apatite ; but is 

 quite different in its action before the blowpipe, and much 

 higher in specific gravity. 



Obs. Leadhills, Wanlockhead, and other lead mines of 

 Europe are foreign localities. In the United States, very 

 handsome crystallized specimens occur at King's mine in 

 Davidson county, N. C. : other localities are the Perkiomen 

 arid Pheni -ville mines, Pa. : the Lubec lead mines, Me. ; 

 Lenox, N. Y. ; formerly, a mile south of Sing Sing, N. Y. ; 

 and the Southampton lead mine, Mass. 



The name pyromorphite is from the Greek pwr, fire, and 

 morphe, form, alluding to its crystallizing on cooling from 

 fusion before the blowpipe. 



Mrmetene. An arsenate of lead, resembling pyromorphite in crys- 

 tallization, but giving a garlic odor on charcoal before the blowpipe. 

 Color pale-yellow, passing into brown. H=275 — 3*5. Gr=6 , 41. 

 From Cornwall and elsewhere ; Phenixville, Pa. 



Hedyphane. An arseno-phosphate of lead and lime, containing 2 

 per cent, of chlorine. It occurs amorphous, of a whitish color, and ada- 

 mantine luster. H=3 5 — 4. Gr=54 — 55. From Sweden. 



crocoisite. — Chromate of Lead. 



Occurs in oblique rhombic prisms, massive, of a bright 

 red color and translucent. Streak orange-yellow. H= 

 2-5—3. Gr=6. 



Composition : chromic acid 31*85, protoxyd of lead 68*15. 

 Produces a yellow solution in nitric acid. Blackens and 

 fuses before the blowpipe, and forms a shining slag contain- 

 ing globules of lead. 



Obs. Occurs in gneiss at Beresof in Siberia, and also in 

 Brazil. This is the chrome yellow of the painters. It is 

 made in the arts by adding to the chromate of potash in so- 

 lution, a solution of acetate or nitrate of lead. The chro- 

 mate of potash is usually procured by means of the ore 

 chromic iron, which see, (p. 241.) 



Melanockroite is another chromate of lead, containing 23*64 of chro- 

 mic acid, and having a dark red color ; streak brick red. Crystals 

 usually tabular and reticulately arranged. Gr=575. From Siberia. 



How is pyromorphite distinguished from beryl and apatite ? What is 

 the color of chromate of lead ? its composition? What is it called v\. 

 the arts, and how used ? 



