Process for Refining Lead . 483 
to prevent any loss to the colour, or bad effect to the 
operator. 
NO. 89. 
The .Process for refining Lead, as practised in England \ 
In a Letter from Mr . John Sadler.* 
(With two engravings.) 
MY dear Sir— Citizen Buhamel, in his Memoir on, 
the Refining of Lead in the large way, has given a sketch 
of the process used in England ; if you think the follow- 
ing more detailed description will be acceptable to the 
readers of the Philosophical Journal, it is at your ser- 
vice. 
The object of refining lead is not merely on account 
©f the silver it contains, but to procure it as free as pos- 
sible from the other metals with which it is usually al- 
loyed, and to procure litharge. The silver is only an 
object so far as it helps to pay the expense of re- 
fining. 
The lead produced at the smelting hearths or fur- 
naces in England is never perfectly pure ; it is always 
alloyed with a portion of silver, and most commonly 
with one or most of the following metals; namely, 
zinc, antimony, copper, and arsenic; which render it 
unfit for some of the purposes to which lead is ap- 
plied. 
The operation of refining is founded on the fa- 
cility with which lead is oxidated when exposed to 
heat in contact with atmospheric air, and the pecu- 
liar properties the oxides of lead possess ; being easily 
fused, and in that state oxidating and combining 
Nicholson, vol. 15, p.t. 
