BOOK X.

485

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A —Straight knife having wooden handles. B —Curved knife likewise having

WOODEN HANDLES. C—CURVED KNIFE WITHOUT WOODEN HANDLES. D —SIEVE.

E —Balls. F —Iron door which the master lets down when he refines silver, lest

THE HEAT OF THE FIRE SHOULD INJURE HIS EYES. G —IRON IMPLEMENT ON WHICH THE

WOOD IS PLACED WHEN THE LIQUID SILVER IS TO BE REFINED. H—ITS OTHER PART

PASSING THROUGH THE RING OF ANOTHER IRON IMPLEMENT ENCLOSED IN THE WALL OF THE

furnace. I—Tests in which burning charcoal has been thrown.

hold much less than fifteen librae of silver, others twenty, some thirty, othersforty, and others fifty. All these tests thus prepared are dried in the sun, orset 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 burningcharcoal placed in them. Others use instead of these tests an iron ring; butthe test is more useful, for if the powder deteriorates the silver remains init, while there being no bottom to the ring, it falls out; besides, it is easier toplace in the hearth the test than the iron ring, and furthermore it requiresmuch less powder. In order that the test should not break and damage thesilver, some bind it round with an iron band.

In order that they may be more easily broken, the silver cakes are placedupon an iron grate by the refiner, and are heated by burning charcoalplaced under them. He has a brass block two palms and two digits long andwide, with a channel in the middle, which he places upon a block of hardwood. Then with a double-headed hammer, he beats the hot cakes of silver