46$ Process for liefining Lead . 
with most of the metals ; gold, silver, and platina ex- 
cepted. 
The lead to be refined is exposed to the action of heat 
and air upon a cupel or test , composed of a mixture of 
bone and fern ashes in a reverberatory furnace ; the de- 
scription of which, with the different manipulations, are 
as follows : 
The refining furnace is composed of good solid mason- 
ry, bound together with iron bolts. It differs very little 
in its construction from the common reverberatory furnace, 
except the bottom, which is perforated to receive the test 
or cupel. 
Fig. 1, plate 14, is a perspective view of the fur- 
nace with its iron work; a the teazing hole, b aper- 
ture by which the test is supplied with lead, c an 
arch or dome over the feeding hole, communicating 
with the furnace stack by a flue, d area or space 
where the test is taken in and out the furnace, ee two 
strong iron bars to support the test when in its place, 
f cast-iron pot set in masonry, the flue passing into 
the stack of the furnace, g the stack, p the ash pit, 
q an iron bar to slide the ladle on when feeding the 
test. 
Fig. 2, a perpendicular section of the furnace showing 
the test z, supported in its place under the opening of the 
bottom of the furnace by the two wedges rr\ 1c aperture 
for the nozzle of the bellows, s fire bar resting on the 
bearers. 
Fig. 3, plan of the interior of the furnace ; l part of the 
bellows, hh flues from the body of the furnace to the 
stack. 
The same letters in the different plans are meant to de- 
note the same parts. 
Plate 15, fig. 1, plan of the iron frame into which the 
mixture of bone and fern ashes is rammed to form the test. 
