It is quite wonderful what a variety of different methods there are
for making silver vases. We might here begin with the casting of
silver, and then little by little get on to other subjects. There are
three ways of melting silver so that it shall not burn.[117] In the
first you use the bellows, constructing round their mouth a little
brick furnace sufficient to quite cover the crucible, even to be
some four fingers above it; then rub the crucible all over, inside
and out, with olive oil; put the silver into it & place it on the
furnace; you should not have too many coals aglow at first for fear
of cracking the crucible, for that is apt to happen with the sudden
heat, but let it get gradually hotter and hotter, without touching
your bellows, until it is red hot. At this point you gently start
blowing with the bellows. After a while you will see the silver
beginning to float like water; then you strew a handful of tartar
over it, and while it stays a moment so, take a piece of linen
folded four or five times & well soaked in oil, to lay this over the
crucible when you remove it from the coals. Then swiftly take hold
of the crucible with your cramping tongs,[118] a pair of tongs made
specially for catching hold of earthen crucibles, for if you catch
hold of these as you would of iron crucibles you would break them,
but these special tongs support the earthen crucible so that there is
no danger of its breaking. Meanwhile, the moulds for pouring silver
in must be at hand; these are made out of two iron plates of the
requisite size and as occasion shall demand, and beneath[119] them
place a few square rods about the size of your little finger, more or
less, as the work may need. The plates are then bound together with
stout iron clamps, struck with a hammer till they grip the moulds
equally all round. Of these clamps you need six or eight according
to the size of the mould. Then you paint round the junction of the
moulds with liquid clay so as to prevent the silver from coming
through.[120] When your moulds are well warmed, you pour a little oil
into them, and stand them in an earthen pot of spent ashes, or even
on the ground between four bricks, and so pour in your silver.[121]
That is one of the methods of casting.
FOOTNOTES:
[117] _Non si riarda._
[118] _Imbracciatoie._
[119] ‘_Infra_’: _should perhaps better be ‘between.’_
[120] _Per cagione che lo argento non versi._
[121] _The sketch on p. 79 may be taken as illustrative of the
process._