XVI BULLETIN 42, UNITED STATES NATIONAL MUSEUM. 



PLATE XX I Page 154). 



IKOX. 



Piij-min smelting. — Top of coke blast lurnaoe, showing throat of furuace with charge of 

 coke resting on the bell. 



(,Cat. No. 54637, U. S. N. M. From photograph.) 



PLATE XXI (Page 156). 



IKOX. 



Pitl-iron smelting. — Fire-brick stoves for heatiug the blastof air before it goes into the 

 furuace. 



(Cat. No. 54641, U. S. N. M. From photograph.) 



PLATE XXII (Page 156). 



IKOX. 



Pi(l-iron smelting. — General view of Longdate furnace. Longdale, Alleghany County, 

 Virginia. 



At the right is a pile of crushed limestone, and above is an elevated tramway for 

 bringing ia suijplies of ore, fuel, and fluxes. Beyond the tramway is a car being ele- 

 vated to the top of the furnace, containing four buggies of material to be charged into 

 the furnace. The furuace is built of brick, eucircleil by bands of iron. Behind the 

 furnace is the casting house. 



(Cat. No. 50719, U. S. N. M. From Photograph.) 



PLATE XXIII (Page 184). 

 zixc. 



Spelter smelting. — Belgian furnaces of the Passaic Zinc Company, Jersey City, New 

 Jersey. 



Shows the furnace in full blast, the lower rows of condensers have the prolongs at- 

 tached, while the upper two rows have not. White oxide of zinc is being lormed from 

 imperfect condensation at several of the condensers. 



(Cat. No. 54626, U. S. N. M. From photograph. ) 



PLATE XXIV (Page 186). 



ZIXC. 



Oxide smelling. — Oxide furnaces of the Passaic Zinc Company, Jersey City, New 

 Jersey, in full blast. 



The middle row of doors is lor the introduction of the charge; the upper row is for 

 admitting air to oxidize the volatilized zinc, and to cool the products of combustion; 

 the lower doors are for withdrawing ashes and refuse that fall through the grate. The 

 small pipes at the side of each furnace supply air to the furnaces under pressure 

 (blast). The large pipes leading from the tips of the furnaces are to convey the oxide 

 of zincsuspended in the products of combustion and air to the bags, where it is liltered 

 out. In the front of each lurnace is a pile of mixed ore and coal ready to be charged 

 into the furnace. 



(Cat. No. 51102, U. S. N. M. From photograph. ) 



