Lead. 
195 
the liberty of mentioning, as, if it should not succeed, the 
trial will be attended with very little expence. 
Supposing then an horizontal chimney to be built, let 
the end farthest from the fire be turned up by a tube of 
earthen ware, or otherwise, so that the sulphureous acid 
may issue out in a direction parallel to the flue of the 
chimney, and at the distance of about a foot and an half 
above it. Let a number of large globular vessels be made 
of either glass or lead, each of these globes must have two 
necks so as to be capable of being Inserted into one an- 
other ; let these vessels be placed on the flue of the chim- 
ney, the neck of the first being inserted into the tube 
through which we have supposed the sulphureous acid to 
issue, and the neck of the last being left open, for fear of 
injuring the draught of the furnace* Let each of these 
globular vessels contain a small quantity of water, then it 
is conceived, that the heat of the flue will raise the water 
into vapour, and that this watery vapour will be the 
means of condensing the sulphureous acid vapour, if not 
wholly, at least in such a degree as may render the un- 
dertaking profitable.^ When the sulphur is all con- 
sumed, the draught of the furnace may be suffered to 
have its ordinary exit at the end of the horizontal chimney 3 
by a very slight contrivance of a moveable damper. Since 
the first .publication of the preceding Essay, I have seen 
an horizontal chimney at the copper works near Liver- 
pool, where every thing I had said concerning the proba- 
bility of saving sulphur by roasting lead ore, is verifier! 
with respect to copper ore; and I believe a patent has 
been granted to some individual for this mode of collect- 
ing sulphur. Sulphur might be obtained with equal fa- 
cility from the pyrites which is found amongst coal, and 
*The sulphur may be worth saving, but I grea% doubt if ths* 
vitriolic acid be? To 
