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The dawn of metallurgy

 

In ancient times, the four elements were fire, air, earth and water. Who was able to dominate all these elements together, was able to dominate the world. In the specific, if in front of a furnace for metals you were able to control the right temperature of the fire, blow the right amount of air to keep the right heating power, choose the highest quality ores from the earth and dominate the tempering in water..  you were able to create the best weapons for the war, the best tools for the farming and crafting, and your civilization would have flowered before the others, giving you so the power.

Four elements (Air, Fire, Water, Earth) in solar symbol,  Ratomir Wilkowski ^

Before metals, human beings used stones in that called Palaeolithic Age. Very few metals are fundable at their pure form; gold is an example and probably was the first metal to be discovered. Copper followed, another pure fundable metal, and humanity entered so in the Copper era.

< Reproduction of Ötzi the iceman, lived in the Copper Age

The working of these metals was relatively easy. Due to their softness, cold-work was possible (i.e. deformation without pre-heating) and melting was not problematic (melting point of gold and copper around 1000°C). On the other hand, their softness impeded their use for tools and weapons. Stones continued to be used as sharp objects and copper and gold were confined in ornamental crafts.

Copper at the pure form is very rare and blacksmiths started to extract it from its ores, i.e. the smelting. This is a fundamental concept in metallurgy. Except some inert elements, metals bond chemically with other elements like sulphur and oxygen, forming so minerals that we can find during a hike in the mountains.

 

                                         

Types of copper ore. Photographs from the Ko-collection (Japanese), copyright Kyushu University

In the moment these minerals are put in a furnace, the thermodynamic conditions change and elements like oxygen and sulphur at high temperatures find that is more convenient to break the chemical bond with the metal and join with the oxygen in the air to form sulphur dioxide (sulphur case), or with the carbon from the combustible to form oxygen dioxide (oxygen case).

Smelting several ores other metals have been discovered. Tin is one of them, it can be managed very easily (you can melt it at your home when you fix electrical contacts) and it has been found that its mixing with copper gives an alloy three times stronger than pure copper, the bronze. Now a lot of applications were finally feasible, humanity gained a material that would have upset the course of history irreversibly. In the Bronze Age a lot of civilization flowered, other disappeared.

Work in the Bronze Age, Jackson Peter

Tin and copper are not widely spread in the Hearth, famous were the mines of Cyprus, from were Copper name derives. A lot of populations were so able to produce bronze thanks to trade routes but in a certain point of the history, concurrently with the big migrations, these routes interrupted and blacksmiths had to find alternatives metals to bronze.

Iron was a solution but its smelting process is more difficult and expensive (more fuel), it cannot be cold-worked (you need to heat before until it starts to irradiate light) and moreover the resultant metal was still full of impurities. Another issue was the melting, Bronze can be melted quite easily and the crafting of objects by decant of the liquid metal inside clay or a stone moulds was a standard. A little curiosity: seems that the legend of the sword in the stone is after the bronze swords extracted from their stone moulds.

 

One of the Riace bronzes, Museo Nazionale della Magna Grecia,Reggio Calabria, Italy >        

 

 

 

 

 

Artefacts from the Three Age System Culture, Meyers chromolithographs from 1902 v

         

Decant of liquid iron with its melting point of about 1500°C was problematic for the difficulties to reach that high temperature and because melted iron suddenly solidifies and moulds couldn’t be totally filled.

Anyway bronze was not available, the village had to be defended by the enemies that would have raped the women imposing their genome, and the harvest was also ready. Research to improve iron crafting was compulsory and the results were great. When bronze become again available, iron alloyed with carbon to make steel was already much stronger and resistant than the copper-tin alloys that were confined from that moment in artistic applications and whatever was necessary to craft through a complete filling of a mould. Bronze, like water, expands when solidifies and is so capable to fill every detail that the artist has carved in the mould.

The Iron age so began, civilizations still at the bronze were supplanted by those that mastered the forging of steel.  Hittites ruled over the Anatolia, Philistines against Israelites before King David. Romans with their gladius, and also thanks to an unexceptionable organization, were able to built one of greatest empire of the human history.

          

Vercingetorix Throws Down His Arms at the Feet of Julius Caesar. Painting by Lionel Royer, 1899

 

I hope in the next articles to talk more about steel metallurgy when I will discuss the making of great swords, like the Viking Ulfberht or the Japanese Katana.

In conclusion, if you get lost in a desert land after a shipwreck, a nuclear or zombie apocalypse, or other nice stuff, is good idea to have a book of mineralogy in order to identify the metal ores that you can find on your road. Learn which metals can be extracted, crush the ores, collect some stones and clay from a river or lake and bake it to make a furnace that optimizes the heat fluxes and minimize dispersion (I leave the problem to engineers), collect some coal and finally start up a fire (wood doesn’t release enough power). Insert the crushed ores that you have kept aside and leave to smelting for several hours.  Season at the end with salt and pepper to taste.