466 



BRASS 



207 



209 



At the brass manufactory of Hegormuhl, upon the Finon Canal, uoar Potsdam, the 

 following are the materials of one charge : 41 pounds of old brass, 55 pounds refined 

 copper (Garkupfcr) granulated, and 24 pounds of zinc. This mixture, weighing 120 

 pounds, is distributed in four crucibles, and fused in a wind furnace with pitcoal fuel. 

 The waste, upon the whole, varies from 2 to 4 pounds. 



Fig. 209 represents the furnace as it was formerly worked with charcoal ; a, the 

 laboratory, in which tho crucibles were placed. It was walled with fire-bricks. The 



foundations and the filling-in walls 

 were formed of stone rubbish, as 

 being bad conductors of heat ; sand 

 and ashes may be also used ; b, cast- 

 iron circular grating plates, pierced 

 with 12 holes (see Jiff. 208), over 

 them a sole of loam, c, is beaten 

 down, and perforated with holes 

 corresponding to those in the iron 

 discs ; d, tho ash-pit ; e, the bock, 

 a draught flue which conducts the 

 air requisite to the combustion, 

 from a sunk tunnel in communica- 

 tion with several melting furnaces. 

 The terrace or crown of the furnace, 

 /, lies on a level with the foundry 

 floor, h h, and is shut with a tile 

 of fire-clay, g, which may be moved 

 in any direction by means of hooks 

 and eyes in its binding iron ring. 

 Fig. 209 the tongs for putting in and 

 taking out the charges, as viewed 

 from above and from the side. 



Tho following description of a Continental brass manufactory, by Dr. Uro, it has 

 been thought advisable to retain, with only a few verbal alterations. 



Figs. 210, 211, represent the furnaces more recently constructed for the use of 

 pitcoal fuel; fig. 210 being an upright section, and fig. 211 the ground plan. In 

 this furnace the crucibles are not surrounded with the 

 fuel, but receive tho requisite melting heat from the 

 flame proceeding from the grate upon which it is burnt. 

 The crucibles stand upon seven arches a, which unite in 

 the middle at the keystone, b, Jig. 211; between tho 

 arches are spaces, through which the flamo rises from tho 

 grate, c ; d, is the fire door ; e, a sliding tile or damper 

 for regulating or shutting off the air-draught ; / an in- 

 clined plane, for carrying off tho cinders that fall through 

 the grate, along tho draught tunnel g, so that the air in 

 entering below may not be heated by them. 



The crucibles are 16 inches deep, 9 wide at the mouth, 

 6J at the bottom ; with a thickness in the sides of 1 inch 

 above and 1 below ; they stand from 40 to 50 meltings. 

 The old brass, which fills their whole capacity, is first put 

 in and molted down ; the crucibles are now taken out and 

 charged with the half of the zinc in pieces of from 1 to 

 3 inches in size, covered over with coal-ashes ; then one- 

 half of tho copper is introduced; again dust; and thus 

 tho layers of zinc and copper are distributed alternately 

 with coal-ashes betwixt them, till the whole charge be- 

 comes finally fused. Over all, a thicker layer of car- 

 bonaceous matter is laid, to prevent oxidation of the 

 brass. Eight crucibles filled in this way are put into tho 

 furnace between the 12 holes of the grate ; and over them 

 are laid two empty crucibles to bo heated for tho casting 



operation. In from 3 J to 4 hours the brass is ready to be poured. Fifteen English 

 bushels of coals are consumed in one operation ; of which six are used at the intro- 

 duction of the crucibles, and four gradually afterwards. 



When sheet brass is to bo made, the following process is pursued I- 

 An empty crucible is taken out of the furnace through the crown with a pair of 

 tongs, and kept red hot by placing it in a hollow hearth surrounded with burning 



211 



