BOOK VIII.

279

pounds of ore ; when they are filled they are covered with lids and smearedwith lute.

In Eisleben and the neighbourhood, when they roast the schistosestone from which copper is smelted, and which is not free from bitumen,they do not use piles of logs, but bundles of faggots. At one time, they usedto pile this kind of stone, when extracted from the pit, on bundles offaggots and roast it by firing the faggots; nowadays, they first of allcarry these same stones to a heap, where they are left to lie for some time insuch a way as to allow the air and rain to soften them. Then they make abed of faggot bundles near the heap, and carry the nearest stones to thisbed; afterward they again place bundles of faggots in the empty placefrom which the first stones have been removed, and pile over this extendedbed, the stones which lay nearest to the first lot; and they do this right up tothe end, until all the stones have been piled mound-shape on a bed of faggots.Finally they fire the faggots, not, however, on the side where the wind isblowing, but on the opposite side, lest the fire blown up by the force of thewind should consume the faggots before the stones are roasted and made soft ;by this method the stones which are adjacent to the faggots take fire andcommunicate it to the next ones, and these again to the adjoining ones, andin this way the heap very often bums continuously for thirty days or more.This schist rock when rich in copper, as I have said elsewhere, exudes asubstance of a nature similar to asbestos.

Ore is crushed with iron-shod stamps, in order that the metal may beseparated from the stone and the hanging-wall rock . 8 The machines whichminers use for this purpose are of four kinds, and are made by the followingmethod. A block of oak timber six feet long, two feet and a palm square, islaid on the ground. In the middle of this is fixed a mortar-box, two feet and sixdigits long, one foot and six digits deep ; the front, which might be called a

Historical Note on Crushing and Concentration of Ores. There can be noquestion that the first step in the metallurgy of ores was direct smelting, and that thisantedates human records. The obvious advantages of reducing the bulk of the material tobe smelted by the elimination of barren portions of the ore, must have appealed to metal-lurgists at a very early date. Logically, therefore, we should find the second step inmetallurgy to be concentration in some form. The question of crushing is so much involvedwith concentration that we have not endeavoured to keep them separate. The earliestindication of these processes appears to be certain inscriptions on monuments of the ivDynasty (4,000 b.c. ?) depicting gold washing (Wilkinson, The Ancient Egyptians, London,*874, 11, p. 137). Certain stele of the xii Dynasty (2,400 b.c.) in the British Museum(144 Bay 1 and 145 Bay 6) refer to gold washing in the Sudan, and one of them appears toindicate the working of gold ore as distinguished from alluvial. The first written descrip-tion of the Egyptian methods—and probably that reflecting the most ancient technologyof crushing and concentration—is that of Agatharchides, a Greek geographer of the secondCentury b.c. This work is lost, but the passage in question is quoted by Diodorus Siculus(ist Century b.c.) and by Photius (died 891 a.d.). We give Booth’s translation ofDiodorus (London, 1700, p. 89), slightly amended: “ In the confines of Egypt and the1( neighbouring countries of Arabia and Ethiopia there is a place full of rich gold mines,(i out of which with much cost and pains of many labourers gold is dug. The soil here<( ls naturally black, but in the body of the earth run many white veins, shining like<( white marble, surpassing in lustre all other bright things. Out of these laboriousit mines, those appointed overseers cause the gold to be dug up by the labour of a vast,, multitude of people. For the Kings of Egypt condemn to these mines notorious(i criminals, captives taken in war, persons sometimes falsely accused, or againstwhom the King is incens’d ; and not only they themselves, but sometimes all their