814 



SILVER 



1808 



a, b, c, d, a balcony or platform, which leads to the place of charging, n ; e, f, 

 wooden stairs, by which the workmen charging mount from the ground, p, q, of the 

 works, to the platform ; g, h, brickwork of the furnaces ; i, A-, wall of the smelt- 

 ing-works, against which they are 

 supported; I, upper basin of recep- 

 tion, hollowed out of the brasque (or 

 bed of ground charcoal and clay) 6 ; 

 m, arch of the tuyere v, by which 

 each furnace receives the blast of two 

 bellows; , place of charging, which 

 takes place through the upper orifice 

 , o, of the basin n, o, v, t, of the 

 furnace ; t, a sloping gutter, seen in 

 fig. 1808, formed of slates cemented 

 together with clay. 



In figs. 1808 and 1809, z is the 

 brickwork of the foundations ; m, con- 

 duits for the exhalation of moisture ; 



4, a layer of slags, rammed above ; 



5, a bed of clay, rammed above the 

 slags ; 6, a brasque, composed of one 



.^ 1809 



part of clay and 

 two parts of 

 ground charcoal, 

 which forms the 

 sole of the fur- 

 nace. 



The refinery 

 furnace, or Treib- 

 heerd, of Friecl- 

 richshutte, near 

 Tarnowitz, in 

 Upper Silesia, is 

 represented in 

 Jiff s. 1810 and 

 1811. a, is the 

 bottom, made of 

 slag or cinders ; 



b, the founda- 

 tion, of fire- 

 bricks ; c, the 

 body of the 

 hearth proper, 

 composed of a 

 mixture of 7 

 parts of dolomite 

 and 1 of fire- 

 clay, in bulk ; 

 d, the grate of 

 the air-furnace ; 



c, the fire- 

 bridge ; f, the 

 dome or cap, 

 made of iron- 

 plate strength- 

 ened with bars, 



and lined with clay -lute, to protect the metal from burning; <j, the door of the fire- 



