CHAP. 47. (16.)—THE ORES OF LEAD.

The nature of lead next comes to be considered. There are two kinds of it, the black and the white.[1] The white is the most valuable: it was called by the Greeks "cassiteros,"[2] and there is a fabulous story told of their going in quest of it to the islands of the Atlantic, and of its being brought in barks made of osiers, covered with hides.[3] It is now known that it is a production of Lusitania and Gallæcia.[4] It is a sand found on the surface of the earth, and of a black colour, and is only to be detected by its weight. It is mingled with small pebbles, particularly in the dried beds of rivers. The miners wash this sand, and calcine the deposit in the furnace. It is also found in the gold mines that are known as "alutiæ,"[5] the stream of water which is passed through them detaching certain black pebbles, mottled with small white spots and of the same weight[6] as 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 converted into white lead.[7]

Black lead is not procured in Gallæcia, although it is so greatly abundant in the neighbouring province of Cantabria; nor is silver procured from white lead, although it is from black.[8] Pieces of black lead cannot be soldered without the intervention of white lead, nor can this be done without employing oil;[9] nor can white lead, on the other hand, be united without the aid of black lead. White lead was held in estimation in the days even of the Trojan War, a fact that is attested by Homer, who calls it "cassiteros."[10] There are two different sources of black lead: it being procured either from its own native ore, where it is produced without the intermixture of any other substance, or else from an ore which contains it in common with silver, the two metals being fused together. The metal which first becomes liquid in the furnace, is called "stannum;"[11] the next that melts is silver; and the metal that remains behind is galena,[12] 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.

1. It is most probable that the "black lead" of Pliny was our lead, and the "white lead" our tin. Beckmann has considered these Chapters at great length, Vol. II. p. 209, et seq. Bohn's Edition.

2. Supposed to have been derived from the Oriental word Kastîra.

3. What is here adduced as a fabulous narrative is not very remote from the truth; the Scilly Isles and Cornwall being the principal sources of the tin now employed in Europe. Small boats, corresponding to the description here given, were very lately still in use among the inhabitants of some parts of the south-west coast of England [and on the Severn]. Pliny has already spoken of these boats in B. vii. c. 57.—B. See also B. iv. c. 30, as to the coracles of the ancient Britons.

4. The ores of tin are known to exist in Gallicia; but the mines in that country are very scanty compared to those of Cornwall.—B.

5. "Talutium" is mentioned in B. xxxiii. c. 21.

6. Tin ore is among the heaviest of minerals, though the specific gravity of the metal is small. M. Hæfer is of opinion that these pebbles contained platinum.

7. Or tin. The greater fusibility of the tin producing this separation.—B.

8. We may conclude that the "plumbum nigrum," or "black lead" of Pliny is the Galena or sulphuret of lead of the moderns; it is frequently what is termed argentiferous, i. e. united with an ore of silver, and this in such quantity as to cause it to be worked for the purpose of procuring the silver.—B. See Beckmann, Vol. II. p. 210.

9. "Instead of oil, workmen use at present 'colophonium,' or some other resin."—Beckmann, Vol. II. p. 223. See also B. xxxiii. c. 20.

10. Iliad, xi. 25, and xxiii. 561.—B.

11. Ajasson considers this to be Bismuth; but it is more probable that Beckmann is right in his conclusion, supported by Agricola, Entzel, Fallopius, Savot, Bernia, and Jung, that it was a compound metal, the Werk of the German smelting houses: a metal not much unlike our pewter, probably. See Beckmann, Hist. Inv. Vol. II. pp. 209, 212, 224. Bohn's Edition.

12. See B. xxxiii. c. 31, and c. 53 of this Book.