114 Mr. Vivian's Account of the . [Feb. 



Swansea and Neath. The processes in a copper work are simple : 

 they consist of alternate calcinations and fusions. By the former 

 the volatile matter is expelled, and the metals previously com- 

 bined with the copper oxidized, the general fusibility of the mass 

 being thereby increased. The calcination is in fact a prepara- 

 tory process to the fusion, in which the metallic oxides and 

 earthy matters, being rendered specifically lighter than the metals, 

 float on the surface, and are skimmed off as slags. 



The furnaces in which these operations are performed are 

 reverberatory, and of the usual construction. The substance to 

 be acted on is placed on the body of the furnace or hearth, which 

 is separated from the fire place by a bridge of bricks about two 

 feet in thickness. The flame passes over this bridge, and, rever- 

 berating along the roof of the furnace, produces the required 

 temperature, and escapes with any volatile matter that may be 

 disengaged from the ore or metallic sulphurets through a flue 

 at the opposite extremity of the furnace, which flue communicates 

 with a perpendicular stack or chimney. 



These furnaces are of two descriptions, varying in their dimen- 

 sions and internal form. The calcining furnaces, or calciners, are 

 furnished with four doors or openings, two on each side the 

 furnace, for the convenience of stirring the ore, and drawing it 

 out of the furnace when calcined. They vary in their dimensions, 

 but are commonly from 17 to 19 feet in length from the bridge 

 to the flue, and from 14 to 16 in width ; the fire-place from 4^ 

 to 5 feet across by 3 feet. 



The melting furnaces are much smaller than the calciners, 

 not exceeding 11 or 11^ feet in length by 7-i or 8 feet in the 

 broadest part : the fire-place is larger in proportion to the body 

 of the furnace than in the calciner, being usually from 3^- to 4 feet 

 across, and 3 or 3-£ feet wide, as a high temperature is required 

 to bring the substances with as little delay as possible into 

 fusion. These furnaces have only one door, which is in the 

 front part of the furnace. The accompanying sketches may 

 convey some idea of the construction of these furnaces ; fig. 1 

 being a plan of a calciner ; fig. 2 of a melting furnace. 



