hold much less than fifteen librae of silver, others twenty, some thirty, others
forty, and others fifty. All these tests thus prepared are dried in the sun, or
set in a warm and covered place ; the more dry and old they are the better.
All of them, when used for refining silver, are heated by means of burning
charcoal placed in them. Others use instead of these tests an iron ring ; but
the test is more useful, for if the powder deteriorates the silver remains in
it, while there being no bottom to the ring, it falls out ; besides, it is easier to
place in the hearth the test than the iron ring, and furthermore it requires
much less powder. In order that the test should not break and damage the
silver, some bind it round with an iron band.
In order that they may be more easily broken, the silver cakes are placed
upon an iron grate by the refiner, and are heated by burning charcoal
placed under them. He has a brass block two palms and two digits long and
wide, with a channel in the middle, which he places upon a block of hard
wood. Then with a double-headed hammer, he beats the hot cakes of silver
