I have a small issue with this technology, as it is indivisible from ‘bronze working’ and ‘iron working’ – since it was learned early that making moulds in sand was an obvious way to employ the plasticity of the medium. Swords, scythes, armor and so on are all made by first casting, then forging. Civ IV offers players the opportunity to install forges in cities once the technology is attained, but really, there is scant bronze or iron working without a forge.
But I will take the opportunity here to talk about metals in general.
The ancients discovered seven metals: iron, copper, silver, tin, mercury, lead and gold. An eighth metal wasn’t discovered until 1752 ... and it wasn’t identified in the old world at all, but in Colombia, South America. The metal, found associated with gold in mines, was platinum.
Fifteen more would be discovered by 1800 – cobalt, nickel, manganese, molybdenum, tungsten, tellurium, beryllium, chromium, uranium, zirconium, yttrium, antimony, bismuth, zinc and arsenic. For all these except the last four, only laboratory specimens were available. Cobalt through yttrium were not in common use.
Some of these metals had been employed by alchemists, without much understanding of why their mineral sources interacted with other substances. Calamine (zinc ore) had been known for centuries as “Indian tin” ... and was known to react well with copper – but brass was not a common alloy until the 1780s.
Separating a metal from its source is no easy task, except for the seven base metals listed above. One might wonder how mithril or adamantium fit into the periodic table – except that most DMs don’t bother wondering about such things. It’s inconvenient (described as dull) and unromantic. I do use both in my world, according to my own rules – and I don’t concentrate overmuch on how either is smelted or worked. Obviously, it must be comparatively easy compared with difficult substances like cobalt or yttrium, since we all assume adamantium is present in the medieval world. Conveniently and expressly made by cultures who live deep beneath the earth and possess no earthly means to vent fires or dump slag, of course.
It could be dumped into the Astral Plane, I suppose. Which would make the Astral Plane look like Montgomeryshire or Polish Silesia ... not at all Romantic, unless you’re a D.H. Lawrence fan.
Six of the original seven metals can be cast into various shapes – mercury is the exception, as it is liquid in a warm room. As such, it was very often used as a medicinal tool, and in some ways is effective in that capacity. It also causes mercury poisoning. Mercury also makes a good means for purifying metals – resulting in the poisoning of streams below mining communities, and thus the poisoning of miners through their water supply. Crippled, dying miners overworked by nasty overlords who are prepared to sacrifice them for the sake of silver and gold has a long precedent in history, and still goes on today. It isn’t a popular D&D plot hook ... but it could be.
Tin mixed with copper makes bronze, which is the only comparison to iron in terms of making hardened tools – as I’ve said before, it is expensive. Tin mixed with lead makes pewter, which makes jewellery comparable with silver and gold, and could be improved in lustre when mixed with some silver. The ancients mixed and experimented with all the metals, finding how to make things beautiful or practical, or both.
The effects of this metal experimentation were far reaching. Metal was a mutable substance, like clay used to make pottery – except that metal was much harder, and could be made to take on a point like bone, or an edge like flint, or the weight of stone. It could be spread wide to make shields, or beaten paper thin and grafted onto the surface of a wall. It was ground and made into paint, drunk as a tonic (with varying effects), spun out as thread and sewn into clothing.
Most of all, it was used widely as a tool. Cultures could for the first time cut down whole forests with little trouble, which expanded homebuilding and shipbuilding, leading to exploration and thereafter to exploitation. Stone could be split easily and quickly, through the use of fewer workers, resulting in mass stone construction projects sponsored not by emperors, but by ordinary wealthy people, making private temples, theatres, walls and roads. Road building would lead to trade and solidly built walls to greater security.
Because it is far easier to found metals at a lower altitude (melting point is lower), the jump on metal manufacture was made by lowland cultures – rather than in the highlands, where much of the ore originated. There are exceptions, such as Anatolia (Hittites) and Persia (Medes) ... however, while both those cultures occupied high plateaus, they were considerable lower than the surrounding, mountainous regions.
This metal founding, affecting in turn the manner in which cultures were structured, enabled the building of empires which in turn would destroy the hill peoples, still limited to wooden or flint tools, who still spent most of their time keeping themselves alive. Ultimately, metal casting is a time-saving technology; allow me to give an example.
A spear can be used to catch fish, obviously. It can be cleverly fashioned with barbs so as to make the implement more effective, and with training a hunter can provide enough to feed his family. It does require that the hunter work fairly hard, standing at the ready until a fish appears, throwing the spear in, withdrawing it, throwing it in again ... and all the while standing in what is often very cold water. In tropical climes, the hunter is exposed to dangerous animals like stonefish, or predators.
Compare this with a fish hook. It requires no cleverness to make. It requires very little talent, particularly when the hook is used as a jig or the fishing line is tied to a float. The fisher needs to use virtually no energy in order to reap the meal. The fisher does not need to set foot into the creek or the lagoon. While nets are still used by experts to produce quantities of fish, everyone can make a small effort and feed themselves that day. Even children.
Metals changed daily behavior in hundreds of ways, just like that. Later, of course, they would change behavior in thousands of ways ... but that is down the road.
I know this wasn’t much of a D&D post. There’s little to say about how some people might better choose their equipment, or make better use of the equipment they have. I always think that’s true, but part of my pleasure as a DM is watching my players work it out for themselves. I don’t want to give them hints here.