BOOK XXXI \. xLvi. 155-XLV11. 159 



scale of iron, ten of wax and a pint of oil. When it 

 is desired to cleanse or fill up wounds, wax plaster is 

 added to these ingredients. 



XLVII. The next topic is the nature of lead, of Leadand 

 which there are two kinds, black and white." White '*"• 

 lead (tin) is the most valuable ; the Greeks applied 

 to it the name cassiteros, and there was a legendary 

 storv of their e-oino; to islands of the Atlantic ocean to 

 fetch it and importing it in platted vessels made of 

 osiers and covered with stitched hides. It is now 

 known that it is a product of Lusitania and Gallaecia 

 found in the surface-strata of the ground which is 

 sandy and of a black colour. It is only detected by its 

 weight, and also tiny pebbles of it occasionally appear, 

 especially in dry beds of torrents. The miners wash 

 this sand and heat the deposit in furnaces. It is 

 also found in the goldmines called ' alutiae,' through 

 which a stream of water is passed that washes out 

 black pebbles of tin mottled with small white spots, 

 and of the same weight as gold, and consequently 

 they remain with the gold in the bowls ^ in which 

 it is coUected, and afterwards are separated in the 

 furnaces, and fused and melted into white lead. 

 BLack lead does not occur in Gallaecia, although the 

 neighbouring country of Biscaya has large quantities 

 of black lead only ; and white lead yields no silver, 

 although it is obtained from black lead. Black lead 

 cannot be soldered wath black without a layer of 

 white lead, nor can white be soldered to black with- 

 out oil, nor can even white lead be soldered with 

 white \\ithout some black lead. Homer testifies /z. xi, 25; 

 that white lead or tin had a high position even in the ^74^0^^^^ 

 Trojan period, he giving it the name of cassiteros. xxiii, 5ci. 

 There are two different sources of black lead, as it is 



241 



