bellows in rotation. Finally we must not omit to state that this is only one
of many such axles having cams and a water-wheel.
I have arrived thus far with many words, and yet it is not unseasonable
that I have in this place pursued the subject minutely, since the smelting of all
the metals, to which I am about to proceed, could not be undertaken without
it.
The ores of gold, silver, copper, and lead, are smelted in a furnace by
four different methods. The first method is for the rich ores of gold or silver,
the second for the mediocre ores, the third for the poor ores, and the fourth
method is for those ores which contain copper or lead, whether they contain
precious metals or are wanting in them. The smelting of the first ores is
performed in the furnace of which the tap-hole is intermittently closed ; the
other three ores are melted in furnaces of which the tap-holes are always
open.
First, I will speak of the manner in which the furnaces are prepared for
the smelting of the ores, and of the first method of smelting. The powder
from which the hearth and forehearth should be made is composed of charcoal and earth (clay ?). The charcoal is crushed by the stamps in a mortarbox, the front of which is closed by a board at the top, while the charcoal.
