BOOK XXXIII. XXXV. 107-109 



a spit in the actual flame, in order to make it of 

 moderate weight. Really, as may be inferred from 

 its name, it is the scum of a substance in a state of 

 fusion and in process of production. It differs from 

 dross in the way in which the scum of a liquid may 

 differ from the lees, one being a blemish excreted by 

 the material when purifying itself and the other a 

 blemish in the metal when purified. Some people 

 make two classes of scum of silver which they call 

 ' scirerytis ' and * peumene,' and a third, leaden 

 scum,** which we shall speak of under the head of xxxiv. 

 lead, To make the scum available for use it is i^^^' 

 boiled a second time after the ingots have been ■vdphide. 

 broken up into pieces the size of finger-rings. Thus 

 after being heated up with the bellows to separate 

 the cinders and ashes from it it is washed with 

 vinegar or wine, and cooled down in the process. 

 In the case of the silvery kind, in order to give it 

 brilliance the instructions are to break it into pieces 

 the size of a bean and boil it in water in an earthen- 

 ware pot Nvith the addition of wheat and barley 

 ^vrapped in new linen cloths, until the cereals are 

 stripped of their husks. Afterwards they grind it 

 in mortars for six days, three times daily washing it 

 with cold water and, when they have ceased opera- 

 tions, with hot, and adding salt from a salt-mine, 

 an obol weight to a pound of scum. Then on the 

 last day they store it in a lead vessek Some boil it 

 with white beans and pearl-barley and dry it in the 

 sun, and others boil it with beans in a white woollen 

 cloth till it ceases to discolour the wool ; and then 

 they add salt from a salt-mine, changing the water 

 from time to time, and put it out to dry on the 40 

 hottest days of summer. They also boil it in a sow's 



83 



