BOOK X. 



485 



A STRAIGHT KNIFE HAVING WOODEN HANDLES. B CURVED KNIFE LIKEWISE HAVING 



WOODEN HANDLES. C CURVED KNIFE WITHOUT WOODEN HANDLES. D SlEVE. 



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, 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 



