BOOK XXXIV xLvii. 159-XLV111. 161 



either found in a vein of its own and produces no 

 other substance mixed with it, or it forms together 

 with silver, and is smelted with the two veins mixed 

 together." Of this substance the Hquid that melts 

 first in the furnaces is called stagnum ^ ; the second 

 liquid is argentiferous lead, and the residue left in 

 the furnaces is impure lead '^ which forms a third 

 part of the vein originally put in ; when this is 

 again fused it gives black lead, having lost two- 

 ninths in bulk. 



XLVIII. When copper vessels are coated with 

 stagnum the contents have a more agreeable taste 

 and the formation of destructive verdigris is pre- 

 vented, and, what is remarkable, the weight is not 

 increased. Also, as we have said, it used to be xxxiil 

 employed at Brindisi as a material for making 

 mirrors which were very celebrated, until even 

 servant-maids began to use silver ones. At the 

 present day a counterfeit stagnnm is made by adding 

 one part of white copper ^ to two parts of white lead ; 

 and it is also made in another way by mixing together 

 equal weights of white and black lead : the latter 

 compound some people now call ' silver mixture.' 

 The same people also give the name of ' tertiary ' 

 to a compound containing two portions of black lead 

 and one of Avhite ; its price is 20 denarii a pound. 

 It is used for soklering pipes. More dishonest 

 makers add to tertiary an equal amount of white 

 lead and call it ' silver mixture,' and use it melted 

 for plating by immersion any articles they wish. 

 They put the price of this last at 70 denarii for 1 Ib. : 

 the price of pure white lead without alloy is 80 denarii, 

 and of black lead 7 denarii. 



The substance of white lead has more dryness, 



243 



