250 Lead \ 
with soft clay, make fire in the fire- hole as for the common 
operations of refining. 
When the lead is in complete fusion, and the mass is 
covered with scum and charred straw, make the scum or 
dross run off by the gutter for the litharge with a bit of 
board about a foot in length, in the middle of which is 
fastened a rod of iron of sufficient length to traverse the 
furnace and about a yard more. 
When the lead has been well scummed several times, 
and begins to be red, make the bellows act, but at first 
gently ; arrange the nozzles of them in such a manner, 
that the wind issuing from both may be directed to the 
centre of the cupell ; and in order that the wind may be 
always reverberated on the mass, adapt to the extremity of 
each nozzle a small round piece of iron plate. This 
kind of valves, which the French refiners call papillons , 
is employed for refining according to the German method. 
They are suspended by hinges at their upper part : at 
each stroke of the bellows they are half raised, and they 
reverberate the wind on the lead, which accelerates its 
oxydation. 
After all the dross or scum is removed, and when the 
lead has become exceedingly red, and covered with a stra- 
tum of litharge, form, with a small iron hook destined for 
that purpose, a small gutter in the sand of the cupell, 
which must be dug deeper, gradually and with caution, 
until the bottom of it be on a level with the mass. The 
litharge then, driven by the wind of the bellows towards 
the anterior part of the furnace, will run by this gutter 
and fall on the floor of the foundry, as is the case in the 
common operations of refining. 
When the refiner observes that no more litharge re- 
mains in the neighbourhood of the gutter, he will stop 
the flowing off with a small quantity of moistened ashes : 
but as soon as the lead again becomes covered with ox yd. 
