Chap. 17.] TJ1K OUKS OF LKAJ). 213 



the stream of water which is passed through them detaching 

 certain black pebbles, mottled with small white spots and of 

 the same weight 90 u* gold. Hence it is that they remain with 

 the gold in the baskets in which it is collected; and being 

 separated in the furnace, are then melted, and become con- 

 verted into white lead. 91 



Black lead is not procured in Gallrocia, although it is so 

 greatly abundant in the neighbouring province of Cantabria ; 

 nor is silver procured from white lead, although it is from 

 black. '** Pieces of black lead cannot be soldered without the 

 intervention of white lead, nor can this be done without em- 

 ploying oil ; M nor can white lead, on the other hand, be united 

 without the aid of black lead. White lead was held in esti- 

 mation in the days even of the Trojan "War, a fact that is at- 

 tested by Homer, who calls it u eassiteros." 9 * There are two 

 different sources of black lead : it being procured either from 

 its own native ore, where it is produced without the intermix- 

 ture of any other substance, or else from an ore which con- 

 tains it in common with silver, the two metals being fused to- 

 gether. The metal which ilrst becomes liquid in the furnace, 

 is called " staiHium ;**** the next that melts is silver; and the 

 metal that remains behind is galena, 95 * the third constituent 

 part of the mineral. On this last being again submitted to 

 fusion black lead is produced, with a deduction of two-ninths. 



Tin ore is union? the heaviest of minerals, though the specific gravity 

 of the metal is small. M. lln'tVr is of opinion that these pebbles con- 

 tained platinum. 



91 Or tin. The greater fusibility of the tin producing this separation. 



tj - We may conclude that the "plumbum nigrutn, 1 ' or *' black lead" of 

 Pliny is the* Galena or sulphuret of lead of the moderns; it is frequently 

 what is termed argentiferous, . e. united with un *re of j-ilver, and this iu 

 such quantity as to cause it to be worked for the purpose of procuring the 

 silver. B. "See Ueckmann, Vol. II. p. 210. 



M "Instead of oil, workmen use at present * eolophoniura,' or some 

 other resin." Heck in aim. Vol II. p. 223. Sec also U. xxxiii. c. '20. 



Iliad, xi. 2.">, and xxiii. 5G1. K. 



9i Aja.sson considers this to be Bismuth ; hut it is more probable that 

 Beckmann is right in his conclusion, supported by Agricola, Kntzel, 

 Fallopiu*, Savot, Hernia, and Jung, that it \v:ts a compound metal, the 

 H'crk of the German smelting- houset : a metal not much unlike our 

 pewter, probably. Sec Ueckmann, Hist. Inv. Vol. II. pp. 209, 212, 224. 

 JEto/j/i'j l'ilitin)i. 



'* See H. xxxiii. c. 31, and c. 53 of this Huok. 



