Leach 
2 39 
ed by subliming sulphur and arsenic together. The work- 
men call the whole of what is separated from the lead in 
the form of smoke, sulphur : when this sublimed matter 
is detached from the roof of the furnace, the red parts are 
converted by a subsequent process, into red lead ; and the 
yellow ones are sent to the smelting furnaces, to be run 
down again into lead. The quantity of this sublimate 
amounts to about live hundred weight in making one 
hundred tons of red lead. The proportion here assigned 
is not wholly to be relied on, since the smoke arising from 
the lead forms itself into larger masses, and in less time, 
when it is not constantly swept from the roof of the fur- 
nace than when it is ; and the workmen endeavour to 
keep the roof as free from it as they can, because a small 
portion of it injures the colour of a large quantity of the 
red lead with which it happens to be mixed. 
A ton or twenty hundred weight of lead generally gives 
twenty-two hundred weight of red lead, notwithstanding 
the loss of substance which the lead evidently sustains 
from the copious smoke which arises from it during the 
operation. 5 * [3 Watson 337. 
The method of making red lead in England : from Jar ? s 
Voyages Metallurgiques, vol. 2, p. 369. There are two 
manufactories of red dead in Derbyshire, at Chester hdd 
and at Worksworth. The furnace appropriated to this 
operation is a reverberatory with two lire places under one : 
and the same arch, which are separated from the floor in 
the middle of the furnace by a wall on each side about 12 
inches high. Each fire place is about 15 inches wide, 
and runs the whole length of th<? furnace from the front to 
the back or -about 9 feet. The distance between the fire 
places on each side is about ten -feet. The mouth or front 
opening of the furnace is about 19 inches by 16 in height: 
neither this opening;, or those of the fire places on each 
side of. it are ever /closed. They are all situated under a 
