"The furnace in the third method of smelting ores has a tap-hole likewise open, but the furnace is higher and wider than the others, and it's bellows are larger; for these reasons a larger charge of the ore can be thrown into it. When the mines yield a great abundance of ore for the smelter, they smelt in the same furnace continuously for three days and three nights, providing there be no defect in either the hearth or in the forehearth. In this kind of a furnace almost every kind of accretion will be found. … However, because large charges of ore are smelted uninterruptly, and the melted material runs out and the slags are skimmed off, there is need of a second forehearth crucible, into which the molten material runs through an opened tap-hole when the first is full. When a smelter has spent twelve hours labour on this work, another always takes his place. The ores of copper and lead and the poorest ores of gold and silver are smelted by this method."

A,B- Two furnaces.  C- Tap-Holes of furnaces.  D- Forehearths.  E- Their tap-holes.
F- Dipping pots.  G- At the one furnace stands the smelter carrying a wicker basket full of charcoal. At the other furnace stands a smelter who with a third hooked breaks away the material which has frozen the tap-hole of the furnace.   H- Hooked bar.  I- Heap of charcoal.  K- Barrow on which is a box made of wicker work in which the coals are measured.  L- Iron spade.
 

This is a reprint from Georgius Agricola's metallurgical classic De Re Metallica. The original latin edition of 1556 AD was translated by Herbert Clark Hoover and Lou Henry Hoover, and published in 1950 by Dover Publications Inc of New York. The text and drawing appear on pages 388 and 389.
 

Howell Foundry L.L.C.

Physical Address

4084 US Hwy. 61
St. Francisville, LA 70775

Phone: (225) 635-CAST (2278)
Fax: (225) 635-4584
:zed@howellfoundry.com
 

Mailing Address

P.O. Box 2487
St. Francisville, LA 70775

www.howellfoundry.com