Metallurgy in West Penwith - Shining Land

Shining Land
The ancient sites of West Penwith, Cornwall
Palden Jenkins
Shining Land
Site nearly complete - organically growing
and what they tell us about megalithic civilisation
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Metallurgy in West Penwith

Prehistory > The Bronze Age
Age of the Longstone Builders | The Bronze Age 2300-800 BCE

Metallurgy in the Bronze Age
Extracted from the book Shining Land, by Palden Jenkins, chapters 17-20.

Tin streaming
One catalyst of change was the use of bronze, which made blades, spades, axes, needles, mirrors, ornaments and other paraphernalia so much more durable, sharp, polished and useful than ever before. Increased productivity brought greater wellbeing, leading to enhanced crop yields, better crafts and woodwork and a host of other benefits. Penwithians’ lives were changing.

It started with copper. West Penwith had modest deposits, though North Wales and the west of Ireland had better ones. In the earliest days, gold and copper could be picked up from the ground, found in streams or shallow-buried in the area between Sennen and Botallack and in places elsewhere. But tin was Penwith’s big asset and, as bronze-working grew, Penwith and other parts of Cornwall and Dartmoor did well. Deep mining was rare because open-cast streaming was easier, although they would dig around if tin was present below the surface, which they could tell by looking for indicator plants and other signs (or the absence of them), and by dowsing.

Streaming was a common technique. This involved channelling and re-routing streams to loosen and erode their banks, exposing metal-bearing lumps that could be caught in the stream, shattered, sorted and smelted. There are quite a few streams in Penwith where signs of streaming remain (though much of it is from recent centuries). Steep-banked streams cut extra deep, with discernible valley levels, are visible in Kenidjack valley, Cot valley (above Porth Nanven), at Nanquidno, Bosigran and Porthmeor just east of Bosigran. Metals were first exported as ore ingots to Ireland, Wales and elsewhere. Only later, around 1800 BCE, did Penwithians develop a forging and metalcraft industry, from which they gained traction, contacts and centrality when they added metallurgy to mining. After 2000 BCE Penwithians also developed copper and gold streaming.

Early hard-rock mining was done by setting fires close to metal-bearing rocks to heat them, and then shattering them with water poured onto the hot rock. Sometimes metal would flow out, but pieces could also be prised out with wood and bone tools, hammered with stone, then sorted to pick out metallic bits. To make copper useful for pouring and moulding in stone, clay or bronze moulds, it had to be heated to around 1,300˚C in pottery crucibles and poured quickly and competently into the moulds – small errors could render a copper or bronze piece useless. Metalsmiths were highly trained specialists, possessing some social and religious status.

Tin was a high-value commodity, and arsenic and cobalt, key hardening ingredients in bronze (ideally comprised of 88-90% copper plus 10-12% tin), were dug up in deposits around Botallack and St Just. These marker ingredients made for sharper, more durable blades for tools and weapons, and they have also allowed archaeologists to determine that Cornwall’s export market stretched as far as the Rhineland, the Baltic and the Mediterranean.

The richest part of the western world was the East Mediterranean, Egypt and Mesopotamia. It had two main sources of quality tin, from Cornwall and Afghanistan. Supplies from both met at the ancient port of Ugarit in today’s Lebanon, at the end of the Silk Road. Traders did not travel all the way from Cornwall to Lebanon – the tin was passed from trader to trader along the route, first to Brittany, down the French coast, up the Loire or Garonne, down the Rhone and across the Med to Sicily, Crete, Egypt, Lebanon and Cyprus (the Med’s main copper source at the time).

Cornish tin travelled down the Atlantic coast to the port of Tartessos, near the Algarve in Portugal, then through the Pillars of Hercules and into the Mediterranean. Here lies the tradition of Phoenicians visiting Cornwall, for which there is much archaeological scepticism, though this settles little. A few Phoenician ships might have come here, one possible explorer being Himilco in the 500s BCE. Hanno the Carthaginian travelled down the African west coast as far as Cameroon in the 400s BCE, seeking sources of gold. It is likely that individual traders or agents came up on Breton boats to visit their trading contacts and the mysterious tin islands. A Phoenician port at Cadiz in SW Spain traded metals from Tartessos, Galicia and Cornwall. In Penwith trading took place at St Michael’s Mount, Porth Ledden, Porth Nanven, Lelant and St Ives.

While mariners will have chosen their summertime sailing days carefully, with noses to the wind and an eye on the currents and weather, Penwith’s culture was very much influenced by its maritime connections, and the metals trade depended on intrepid sailors. They built seagoing boats of wood with big leather sails to withstand journeys to mainland Europe and up the Celtic and Irish seas as far as the Hebrides and Orkney. Tin ingots, heavy but not large, were quite transportable, serving as good ballast.

Shining Land
A book by Palden Jenkins about the ancient sites of West Penwith in Cornwall
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