BOOK VII. 



229 



B TRIANGULAR CRUCIBLE. C CUPEL. 



iat from the ashes, still the cupels which are made from such ashes are not 

 very good because they often contain charcoal dust, sand, and pebbles. 

 Some make them in the same way out of any kind of ashes, but first of all 

 pour water into the ashes and remove the scum which floats thereon ; then, 

 after it has become clear, they pour away the water, and dry the ashes ; they 

 then sift them and make the cupels from them. These, indeed, are good, 

 but not of the best quality, because ashes of this kind are also not devoid of 

 small pebbles and sand. To enable cupels of the best quality to be made, all 

 the impurities must be removed from the ashes. These impurities are of 

 two kinds ; the one sort light, to which class belong charcoal dust and fatty 

 material and other things which float in water, the other sort heavy, such 

 as small stones, fine sand, and any other materials which settle in the 

 bottom of a vessel. Therefore, first of all, water should be poured into the 

 ashes and the light impurities removed ; then the ashes should be 

 kneaded with the hands, so that they will become properly mixed with 

 the water. When the water has become muddy and turbid, it should be 

 poured into a second vessel. In this way the small stones and fine sand, or 

 any other heavy substance which may be there, remain in the first vessel, 

 and should be thrown away. When all the ashes have settled in this second 

 vessel, which will be shown if the water has become clear and does not taste 

 of the flavour of lye, the water should be thrown away, and the ashes 

 which have settled in the vessel should be dried in the sun or in a furnace. 

 This material is suitable for the cupels, especially if it is the ash of beech 

 wood or other wood which has a small annual growth ; those ashes made 

 from twigs and limbs of vines, which have rapid annual growth, are not so 



