BOOK XXXIII. XLV. 129-XLV1. 132 



laid flat or placed upright, as the quaUty of the shape 

 receiving the shadows twists them as they come : 

 for in fact the image in a mirror is merely the shadow 

 arranged by the brilHance of the material receiving 

 it. And in order to complete the whole subject of 

 mirrors in this place, the best of those known in old 

 days were those made at Brindisi of a mixture of 

 stagnum " and copper. Silver mirrors have come to 

 be preferred ; they were first made by Pasiteles in 

 the period of Pompey the Great. But it has c 106-48. 

 recently come to be believed that a more reliable °*°* 

 reflection is given by applying a layer of gold to the 

 back of glass.^ 



XLVI. The people of Egypt stain their silver so 

 as to see portraits of their god Anubis in their 

 vessels ; and they do not engrave but paint their 

 silver. The use of that material thence passed 

 over even to our triumphal statues, and, wonderful 

 to relate, its price rises with the dimming of its 

 brilliance. The method adopted is as follows : with 

 the silver is mixed one third its amount of the very 

 fine Cyprus copper called chaplet-copper ^ and the 

 same amount of live sulphur as of silver, and then 

 they are melted in an earthenware vessel having its 

 lid stopped with potter's clay; the heating goes on 

 till the lids of the vessels open of their own accord. 

 Silver is also turned black by means of the yolk of a 

 hard-boiled egg, although the black can be rubbed 

 off with vinegar and chalk. 



The triumvir Antony alloyed the silver denarius Dehasedand 

 with iron, and forgers put an alloy of copper in silver So^e! ^ 

 coins, while others also reduce the weight, the 

 proper coinage being 84 denarii from a pound of 

 silver. Consequently a method was devised of 



99 



