20 2 
Lead . 
masses are taken to a kind of blast furnace, called a slag- 
hearth. By this second fusion of the scoriae, the lead 
drops through the liquid mass into the lower part of the 
hearth, where it is not acted upon by the blast, and from 
thence is let off and cast into pigs. This lead is said to 
be of an inferior quality. Some ores of lead contain sil- 
ver. The great affinity of lead for that metal is such, that 
the whole of it is found in the lead, from whence it is af- 
terwards separated. [Brewster's Cyclopedia. 
On the Smelting of Lead. 
Dear Sir — -M ost of the lead of commerce is obtain- 
ed from that species of ore which is by mineralogists call- 
ed galena , potter's ore , or sulphuret of lead. Indeed, it 
is the only species of lead ore which is found in sufficient 
quantities to be worth working. 
There are many other species of lead ore met with oc- 
casionally ; but these, occurring but seldom, are regard- 
ed as curiosities, and are generally carefully selected for the 
cabinet of the mineralogist, or as ornaments for the man- 
tlepiece of the miner. 
The ore, as it is first raised from the mine, is mixed 
with a considerable proportion of the matrix or gangue of 
the vein, from which it must be in great measure freed 
before it is fit for the operation of smelting. 
For this purpose, the ore is delivered to the dressers , 
who either break it into dmall pieces with hand-hammers 
of a peculiar construction, which are called buckers , or it 
is passed between rollers worked by machinery, or un- 
der stampers. It then undergoes the operation of wash- 
ing, to separate it from the lighter foreign matter, after 
which it is ready for the smelter. 
Construction of the Ore Hearth. 
The smelting of lead is performed differently in different 
districts. In mast parts of the North, particularly in 
