878 Dr. watson’s Experiments and. 
chimney pieces, and other matters. It arifes from the 
fpar mixed with the ore, and, by the addition of fufible 
fpar to the ore during its fufion, its quantity might be 
increafed at no great expence, in any proportion. That 
part of the ore which is fublimed and difperfed in the 
air, confifts partly of the fulphur which is confirmed, 
and partly of lead; this fublimed lead attaches itfelf in 
part to the lides of the chimney of the fmelting furnace ; 
the reft of it flies up into the air, from whence it falls 
upon the ground, poifoning the water and herbage upon 
which it fettles,. This fublimed lead might be collected 
either by making it meet with water, or with the vapour 
of water during its afcent, or by making it pafs through 
an horizontal chimney of a fufflcient length. 
It is not eafy to determine with precifion the quantity 
of this fublimed lead; a general guefs, however, may 
throw fome light upon the fubject. They ufually at a 
fmelting houfe work off three tons, or fixty hundred 
weight, of lead ore every twenty-four hours ; the fulphur 
contained in fixty hundred weight of ore we will fup- 
pofe to be feven hundred weight, and the lead to be 
forty hundred weight ; the air, liquid, fcoria, and fub- 
limed lead, muft together, upon this fuppofition, amount 
to thirteen hundred weight ; now, admitting three hun- 
dred weight of the thirteen to be fublimed lead, it is 
evident 
