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Post by marchesarosa on Mar 3, 2011 8:20:50 GMT 1
I have often wondered how stone age man "discovered" metal and Neil Oliver's "A History of Ancient Britain" on BBC Two last night reminded me of the puzzle again.
He begged the question, however, with the statement that metallurgy was brought to British Isles (southern Ireland) by the Beaker People.
But how did THEY acquire the insight that veins of mineral in stones could be extracted and transformed into copper by smelting? Not exactly obvious how this insight could arise, is it?
Does anyone have an opinion?
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Post by rsmith7 on Mar 3, 2011 8:44:45 GMT 1
Could they have built a fire on stones containing ore and found the shiney, useful metal in the ashes and put two and two together?
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Post by marchesarosa on Mar 3, 2011 9:32:51 GMT 1
Maybe, Mr Smith. Fire is a great transformer. Apparently that is how soap was discovered - congealed melted fat from roasted meat in the ashes of the fire.
I'd like to see an experiment to establish whether the temperature of a domestic fire could melt ore.
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Post by abacus9900 on Mar 3, 2011 10:42:10 GMT 1
It has been suggested that someone accidentally dropped a piece of metal in a fire, say copper, and then noticed how pliant it became for working.
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Post by marchesarosa on Mar 3, 2011 12:32:08 GMT 1
But where did that "piece of metal" come from, abacus?
It doesn't occur naturally, does it?
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Post by jonjel on Mar 3, 2011 12:56:00 GMT 1
It does Marchesa, in crude forms as veins of metal. No doubt at the surface in some places, and certainly tin silver and gold are found as metals.
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Post by jonjel on Mar 3, 2011 12:57:45 GMT 1
PS.
I seem to remember that gold melts at 1050 C, and both tin and silver a lot less, so a decent fire would easily deal with them.
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Post by jean on Mar 3, 2011 13:37:53 GMT 1
And then there's
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Post by carnyx on Mar 3, 2011 15:00:52 GMT 1
Marchesa,
There are re-enactors in the Alps who go on holiday in the wilds and try to live the Otzi-era life. I heard of one group smelting a local copper ore (green malachite) in an ordinary wood fire, and it seemed very easy. They produced cast copper axes, and whilst they do not hold an edge for as long as bronze, they are perfectly useable and make good swords and arrow-heads ( which hopefully aren't used to cut as often as an axe.)
And also, it only takes a pinch of tin to turn copper into bronze, which is a very different colour to copper, and much harder. And as both ores are found together in Cornwall particularly, it would only be a matter of time before the insight was made. Also, tin for bronzemaking would be ideal to trade, as small quantities of this high-value powder could easily be carried in say goosequills sealed with wax. In addition, zinc ore in the form of calomel ( pinkish soft crumbly stuff which when powdered makes calamine lotion ) is also found with copper and tin deposits. When calomel ore is smelted with copper ore you get brass, which is sufficiently gold-looking that this started rumours and the universal search for the 'philosophers stone'. It took a long time to get native zinc, as it requires a vaccum to get it out of the calomel ore.
Then, native copper can be found at the top-end of copper veins, which can be spotted in the Cornish sea-cliffs as veins of iron rust in the rocks, which have been formed by ion exchange with copper via the seawater. I forget the exact sequence, but further down in the vein you will get the native copper, and blue copper sulphate further down, the various greeen ans black copper oxides that are mined in quantity. Prehistoric man probably mined directly into the bigger vertical veins in the cliffs, widening them into charactreristic clefts called 'zawns' today ...
( BTW .. Penwith is a great location for a holiday)
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Post by carnyx on Mar 3, 2011 15:02:17 GMT 1
PS re simplex photo , that looks like women's work to me!
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Post by speakertoanimals on Mar 3, 2011 16:44:52 GMT 1
(I'd meant to delete bit about flint -- apparently flint CAN be heat-treated to make it easier to work, but just chucking it on a fire more likely to just crack it! seems to help MORE with other rocks, where fire can make it possible to chip then)
Once you know that some metals occur as chunks of metal in rocks (native copper and native gold), then we have a route to full smelting.
Apparently those who used stone in general (not necessarily flint) would easily notice that stones that had been in the fire were easier to chip, because anyway you'd have used stones to surround your fire anyway, so mucking about with the heated stones lying about afterwards would have been an obvious thing for people to do. Hence they discovered they were easier to chip after heating.
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Post by marchesarosa on Mar 3, 2011 18:45:26 GMT 1
Thanks all.
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