Wondering about smelting

Rabbit tracking about the bronze age, I ran across a Journal of African History article about smelting in Africa. One item of regret in the article: "Nevertheless, the study of forging or smithing practice generally has been neglected in favour of studying the smelting process. Undoubtedly, the near-indestructibility of smelting slags has contributed to this situtation, but, as was pointed out by Stanley in 1929, so has the understandable reluctance of curators to submit metal artefacts for destructive metallographic analysis."

Some scholars have been very eager to move iron smelting into the first millenium BC in sub-Sarahan Africa, but once you get away from Meroe (Nubia, in ages-old contact w/ Egypt), the evidence is pretty frail and disputed, the wikipedia article on Bantu expansion to the contrary. The chronology is muddled, but it looks as though both iron and bronze started being made a bit before 1000AD. (Coincidentally, that's about the time the Andeans started making bronze too. It seems bronze was rare and beautiful enough that they used it for ornamets rather than tools/weapons. Maybe given more time--but they didn't have time.)

The failure of iron smelting technology to spread seems to demand a little explanation. There would be two main secrets: what was the rock used, and what was the procedure. After knowing those, you could figure out the details with trial and error. And, once these were known, the technology did spread. Low grade iron ore is fairly widespread, and charcoal is not hard to come by either.

In fact, I'd think making bronze would have been the trickier thing to teach. Tin is rare. Spies in Nubia wouldn't know exactly where the ore came from (not local). There's some in what's now Nigeria, and once they figured that out they started in making bronzes--now famous. Copper -- that people already had.

At any rate, I wonder if there was an effort to keep the materials and process secret from the rest of the Africans. It would help with the Nubian balance of trade ...

The rest of Africa did learn. The way smelting was treated is suggestive: "The operations of sub-Saharan smelters were associated almost ubiquitously with extensive ritual. ... The smelter's role was identified as special, with the smelter accorded a particular status, either elevated or in some cases as a member of an outsider caste. ... The reproductive symbolism of the smelting process was often made explicit by the anthropomorphic design of furnaces found ranging from Nigeria to southern Africa." (The emergence of the bloom of iron was like a birth.)

The symbolism and secrecy could have developed independently in each place, but I suspect they were there from the start--from the first men (women were not allowed) who learned smelting. Did they pick that up from the Nubians?

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I've had a hobby of trying to figure out how people with limited resources would discover things. For example, unless you have enough metal to experiment with, and possibly waste, you're not likely to try to mix metals to see what you get. Take bronze, discovered/created over 6000 years ago. Copper is moderately common, tin is rare. If you only have a little bit of tin, you'll be very careful with it.

Discovering what happens when you mix it with copper is only likely to happen by accident--if you try stirring melted tin with a copper rod, for instance. Even small amounts of bronze would be a very interesting discovery and prompt further investigation. After some trial and error, you'd discover that you didn't need much tin in your copper. Some people suggest the discovery came when copper and tin ore rocks mixed in the same charcoal fire, but a copper pot plus charcoal in a bed of tin ore rubble plus somebody being careless with the fire seems more likely.

If you are a tin producer, you might try adulterating the product, and wind up with something odd. Very odd, and maybe worth researching. And as a tin producer, you might have enough tin to research with. (On the other hand, I'd expect that you would then import copper and export bronze, but in real life the bronze producers imported tin.)

If you're rich enough to do alloy research, to try to find something as good as that famous type of copper that's so extra hard, you'll come up with some interesting things eventually. It'll take a while to find a good mixture, but even if you die of arsenic poisoning somebody else can take up the work where you left off.

I'd like to think it was the third possibility--I'm fond of basic research--but I think it might have been the second.