Nature's Evil [calibre 5.27.0]

If you added black sand to a furnace, then – with luck – the alloy produced would be sturdier than ordinary copper. This alloy of copper and tin was bronze; people started making tools and weapons out of it. But in the bogs of Mesopotamia and the delta of the Nile even stone was a curiosity. Nomads from the North supplied metals to the nascent civilisations of the Middle East in exchange for artisan products from the South. But, in their search for wood and metal, people from these fertile plains migrated ever further north – to Lebanon, Anatolia and the whole Mediterranean. Egyptians extracted copper from mines in Sinai and captured gold mines in Nubia. Weapons made of metal allowed them to control the peasants who dug the earth with wooden implements. Synonymous with control over grain stores and cedar forests, power was now concerned with mines, furnaces and delivery routes.

Armed with the sword, the plough and the wheel, civilisation moved north. Smithies appeared in peasant villages. Their owners made a living by barter, not by agricultural labour, and were often considered as interlopers and magicians; many of them were migrants. Metallurgy needed men to assemble various resources – for example, copper, tin and charcoal – in one place, although they were all sourced from different areas. There were many deposits of copper ore in Europe; tin, less common, had to be brought from far away. In bronze alloys, tin made up less than a fifth by weight, but its sources were distant and limited, which meant that tin was expensive to barter. Alternatively, smiths could make bronze by smelting copper with poisonous arsenic. They died young, and although the god of blacksmithing, Hephaestus, was depicted with powerful shoulders, he was lame in both legs. But he forged weapons that were prized by the gods, and he was married to the beautiful Aphrodite.

At about the same time as people were learning to combine tin and copper, they also discovered how to separate silver. They heated ore in a hearth to the highest temperature they could achieve. Tin melted in the hearth and flowed out as if from a font or cupel, and the silver remained inside. This miraculous process was called cupellation. Athens rose thanks to the silver in the Laurion mines of Attica. The mines belonged to the state, although they were often farmed out to private individuals; nameless slaves worked the mines. From approximately 500 bce the profits from silver and tin financed the creation of a navy and the upkeep of a mercenary army. The Athenians also used this silver to maintain grain colonies in North Africa and the Mediterranean, thus avoiding the dirty work of earning their daily bread. A little later the Thracian mines in northern Greece produced even more silver; at one time they were run by Thucydides, the first historian. These mines were the source of power of the Macedonian dynasty that gave the world Alexander, the conqueror of Asia. The Phoenicians worked even richer mines in Spain. Hannibal financed his expeditions from these mines; indeed, behind every military leader there was a silver or copper mine. From his mines near Cadiz, Sextus Marius supplied Rome with both metals; as we remember (see Introduction), Tiberius accused him of incest and threw him off a rock.

The Roman Empire grew like an amoeba, spreading its tentacles now in one direction, now in another. According to the anthropologist Jack Goody, the main motive behind these advances was the quest for metals. 1 The goals of Roman colonisation were copper in southern Italy, tin in England, silver in Spain, and lead in Attica and Sardinia. The Romans loved soft, malleable lead and used it for plumbing and baths and as vessels for soft drinks. Lead salts dissolve in water, and this solution is sweet but poisonous. Lead acetate causes organ failure, and small doses cause brain damage in children. According to one study, more Roman emperors died of lead poisoning than died by the sword. 2

Smelting furnaces, sunk in the earth and faced with bricks, appeared in different parts of the world – in Western Europe, South-East Asia, northern China. The quality of the metal depended on the temperature in the furnace, which in turn depended on the up-draught, which depended on the height of the chimney, which depended on the quality of the brick. Progress in smelting was advanced by a breakthrough in firing clay. Smelting furnaces with chimneys 4 metres high were the ultimate in the art of engineering in the Bronze Age. Such furnaces were ready for smelting iron.

A noble metal that did not rust, bronze had its limits: a short sword could be made out of bronze, but not a long sabre. Bronze shields and armour offered little protection against the crude but heavy weapons of the barbarians. For making ploughs, bronze was too expensive and also prone to wear and tear. The extended delivery routes for tin were the weak spot in the production of bronze. With time, the invasion by the ‘people from the sea’ – the barbarian tribes from Eastern Europe who used iron – destroyed the ancient supply routes for tin. Relying on rare and remote resources, the Bronze Age was a time of social inequality. The owners of pits and mines became rich, but even they depended on those who controlled the delivery routes. 3