192 
Lead . 
the ore pass through a horizontal chimney, with various 
windings to condense the vapour. I have since conversed 
with some of the principal lead smelters in Derbyshire , 
and find that I had over-rated the quantity of this sub- 
limed lead ; the weight of the sconce from a ton of ore, 
amounting to more than I had supposed ; they were all 
of them, however, of opinion, that the plan I had proposed 
for saving the sublimate, was a very rational one. But 
so difficult is it to wean artists from their ancient ways of 
operating, that I question very much whether any of them 
would ever have adopted the plan they approved, if an ho- 
rizontal chimney, which was built a little time ago in 
Middleton dale , for a quite different purpose, had not given 
them a full proof of the practicability of saving the subli- 
mate of lead, which was lost in the ordinary method of 
Smelting. This chimney was built on the side of an hill 
to prevent some adjoining pastures from being injured by 
the smoke of the furnace. It not only answers that end, 
but it is found also to collect considerable quantities of the 
lead, which is sublimed during the smelting of the ore ; 
this sublimed lead is of a whitish cast, and is sold to the 
painters at ten or twelve pounds a ton ; it might perhaps 
be converted into red lead with still more profit. 
A second circumstance to be attended to in the smelt- 
ing of lead ore, is the saving the sulphur contained in it. 
The pure lead ore of Derbyshire contains between an 
eighth and a ninth part of its weight of sulphur ; but as 
the ore which is smelted is never pure, being mixed with 
particles of spar , caivk, limestone , brazil, and other sub- 
stances, which the miners call deads we shall be high 
enough in our supposition, if we say that the ordinary ore 
contains a tenth of its weight of sulphur ; it may not, pro- 
bably, contain so much, but even a twelfth part, could it 
be collected at a small expence, would be an object of 
great impartance to the smelter. In the common method 
