CHAP. 51.—FIFTEEN REMEDIES DERIVED FROM THE SCORIA OF LEAD.
The scoria [Note] of lead is also made use of; the best kind being
that which approaches nearest to a yellow colour, without any
vestiges of lead, or which has the appearance of sulphur without
any terreous particles. It is broken into small pieces and
washed in a mortar, until the mortar assumes a yellow colour;
after which, it is poured off into a clean vessel, the process
being repeated until it deposits a sediment, which is a substance
of the greatest utility. It possesses the same properties
as lead, but of a more active nature. How truly wonderful is
the knowledge which we gain by experiment, when even the
very dregs and foul residues of substances have in so many
ways been tested by mankind!