Copper . S3 
tide Silver. In all the different roastings and reductions 
necessary to bring the copper to purity, the silver remains 
united with it. \_Aikin. 
I have translated the following account from Hellot’s 
Schl utter, v. 2. p. 496 ; it is the substance of the best 
methods detailed by him. His work, like that of Jars, 
who wrote long after him, contains not only detailed ac- 
counts of the processes of various works, but plates of the 
various furnaces in use. I give none of these, being per- 
suaded that the well known and long-approved Cupola 
furnace of the lead and copper works of England, is pre- 
ferable. 
At the Bristol foundery, they smelt the copper ores of 
Cornwall, Devonshire and New York, in a reverberatory 
furnace such as is used for lead. The ore is broken into 
small pieces of the size of a walnut. The hearth is made 
of sea sand : the basin that receives the metal let out, is 
made in the same way. They are baked by the heat of 
stone coal. The ore is also heated in the same manner 
which serves also for roasting. This poured on the hearth 
through a hole in the arch by means of a hopper, and the 
hole is then closed : it is thus fed with four quintals of ore 
every four hours. The coals are lighted on a grate on 
each side of the hearth, and the fame reverberates on the 
ore from the arch, as in a red-lead furnace : the ore is 
thus roasted and then melted. The sconce are raked off 
by an opening left for this purpose. I he matt, or crude 
metal, is run off every 24 hours. This furnace is kept in 
blast for a twelve month together. 
Secondly, The crude metal broken in pieces, is placed 
on the same kind of hearth in another furnace, and kept 
under the flame of the reverberatory for 18 hours : it is 
then let out into a basin or reservoir of sea sand, some- 
times cemented by being mixed with finely powdered 
glass, and then exposed to strong heat. This operation, 
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