COI.LKCIIONS IN KCO.NOMIC (JKOI.OCY AND MKTAI.I.I 'K(i Y I HT) 



witli ten ill a row. 'I'lu- usual cliarp" consi.sts iA' :V2 tu ,;:» ifoiinds ol Ore 

 mixed witli 21 pouiuls ol' aiiiiiiaciU' coal dust. 



The oxide luMiaeesconiiiioiil> known as Wrilicrill liirnaceHan' siiiii)ly 

 rectan<rular fiiniaees (» feet by l Iret, witli an ardied roof.'Mot feet 

 above the ;;iate whieh eoiisists of perforated iron shibs. '1' he re are 

 forty-eij^ht of these furnaces. 



TIm' I'lanUlinile ore is mixed with anthracitf- eoal thist, and charf^ed 

 into these furnaces, tlie metallic zinc is reduced in tin* foim of vapor, 

 and, an excess of air beiiijj: admitted above the fire, it is iuimediately 

 eonveitetl into oxich' of zinc in a very line state of snlxlivisioii. An 

 exhaust fan draws this oxide of zinc suspended in air tlirou;,'li eo()lin<; 

 tubes, and delivers it to a large number of cotton bags which allow the 

 air to.pass throiiiiii, but retain the (►xide of zinc. Froiu time to time 

 tin' oxide of zinc is removed from the collecting apparatus in the form 

 of an impalpable white powder which is used for a white paint. 



The residuum remainiug in the oxide furnace is drawn off and sent 

 to t'le Spiegel furnace. The spiegel furuace is an ordinary blast fur- 

 nace, 37A feet by S feet, which is run in the same manner as an ordinary 

 iron furnace, but with special provisions for collecting the zinc which 

 remains in the residuum, and is driven off during the smelting in the 

 form of oxide, and then collects in the gas ways. Greater care is also 

 necessary in order to keep the furnace running smoothly. The ordinary 

 charge for this furnace is 1,150 pounds of residuum, 1,000 pounds of 

 anthracite coal, 270 pounds of limestone. Fifty to sixty of these 

 charges are made daily, producing about 10 tons of about 20 i)er cent. 

 Spiegel. There are also made about 13 tons of oxide of zinc i)er week, 

 which is smelted in the spelter furnaces. 



A block of the I'lelgian furnaces is shown in PL. win and the oxide 

 furnaces in tl. xxiv. 



The collection taken by Mr. J. B. Mackintosh, E. M., October, 1884, rep- 

 resents a large series of the Franklin ores, the fuel, the intermediate, an«l 

 final products. 



SPELTER FURXACE SAMPLES. 

 Ore. 



(1) Calamine, allowing decomposition. Ogdonsbnrgb, Sutuiex County, New Jersey. 

 (541:j:5.) 



(2) Calcined silicate, linnp ore. (54134.) 



(3) Calcined silicate, crushed, ready for furnaces. (54130.) 



Fiiniaie Chanjc. 

 (1) On-, nuxtd \sitii aiitiiUKitc coal dust. (.'.r>834.) 



I'ri>durt8. 



(1) Spelter or nietullic /.inc. (fjlll'J.) 



{'i) Hlut^ jiowdor, a mixture of metallic zinc and (»xidf of zinc, olitaiucd as a by- 

 product in distilling zinc. (r»4141.) 



(3) Hfsiiluc, remaining in the retorts after reducing and distilling the metallic zinc 

 from the silicate ore. (r>4l43.) 



