240 
Lend \ 
high chimney, common to them ail, and opening inside ; 
so that the furnace is in fact a common baker’s oven, of 
which, the bottom by two walls running the whole length 
of the arch, is divided into three parts ; the middle being 
the hearth on which the lead is placed, in size about 10 
feet by 9 feet, the other two parts on each side being fire 
places of which the dimensions are 9 feet by 12 inches 
and 15 inches. These fire places have neither grate or 
ash hole. The coal in middling sized lumps is thrown 
into these fire places, which it fills to the level of the side 
walls (that is 12 inches high.) The hearth is accurately 
and neatly laid with fire brick, with very small joints and 
is perfectly level. The hearth is common, extending from 
the springing of the arch on one side, to the springing of 
the same on the other, 
About fifteen hundred weight of lead is the common 
charge of the furnace, of which about one-tenth is slag- 
lead, (procured by working the slags over again). The 
workman begins by forming a ledge just inside the mouth 
of the furnace, of the yellowish slag or refuse of the wash- 
ing of the red lead of the preceding charge : this serves 
to keep in the melted lead during the operation. The 
Same from the coal fire on each side strikes against the 
roof of the arch, and is reverberated downward on the 
surface of the metallic lead on the hearth. During all 
this time, a man standing in front of the furnace, rakes the 
melted lead with an iron rake which is suspended by a 
chain hung on the outside of the mouth of the furnace, so 
that the man’s hands are freed from the weight of the 
rake, and he has nothing to do but push it backward and 
forward. As the oxyd forms, he draws it to one, side 
leaving the centre of the hearth filled with melted lead, 
of which by the rake he continually exposes fresh sur- 
faces, until the whole is converted into a dusty oxyd. 
This requires from 4 to 5 or 6 hours. The whole of the 
