Folks,
What is mankind's greatest invention? Some would say the wheel: it's effect on transportation and mobility are unquestioned. Others would argue that the printing press is tops, since it enabled the flow of ideas and record keeping. Many point out that the Protestant Reformation likely would not have happened without the printing press to spread the Reformation ideas.
I went to the internet and found agreement with the wheel and printing press, and saw that many others added electricity, antibiotics, automobile, airplanes, etc.. However, I would argue that hands down, the greatest invention of all is the smelting of copper from ore. Metal was needed for many wheels and certainly for the printing press. We even designate the eras of civilization by the names "stone age", "copper age", "bronze age", "iron age" and perhaps today, the "silicon age". Metals are the foundation of civilization. In addition, the smelting of copper led to the ethos of experimenting that gave us iron, gunpowder, and sparked the human interest in invention.
Another reason I believe that the smelting of copper is the greatest invention is it’s difficulty. I don’t want to minimize the difficulty of inventing the wheel or the printing press. These inventions can seem obvious after we see them, but clearly, they were not obvious to the ancients, as is the case for the wheel, and in relatively modern times for the printing press. These discoveries were difficult in their own right.
Why do I claim the smelting of copper was difficult? For about ten years at Dartmouth, I taught a course to mostly non-engineers, Materials: The Substance of Civilization. In this course, we reviewed how the ancients must have smelted copper. The basic steps follow:
- Crush malachite ore (copper ore: Cu2CO3(OH)2) into a powder
- Build a wood fire to as hot as possible – about 2200°F (1200°C) is needed
- Mix malachite powder with charcoal
- Put the mixture in fire for several hours
Seems simple enough, so I sent some graduate students out to a picnic fireplace with 50 pounds of charcoal, powdered malachite mixed with powdered charcoal, and a leaf blower to stoke the fire. The result: nothing!
The reason was that the students could not achieve even close to the 2200°F needed. Recently, after grilling steaks on our propane grill, I turned the grill on high to burn off the grease on the grill gratings. I read its peak temperature at only 600°F when I turned it off. The heat of the grill felt intimidating as I approached it, but it was still only 600°F!
Achieving 2200°F with a wood or charcoal fire is a great feat!
So how did the ancients achieve 2200°F? This video by @ancient1580 on YouTube shows a likely approach. They built their fire in a hole in the ground and covered it with sod to contain the heat. However, they had to use a bellows for hours to finish the smelting. The steps in the video are bellow:
1. Crush malachite ore (copper ore: Cu2CO3(OH)2) into a powder. See Figure 1.
Figure 1. Crushing malachite ore into a powder was a first step in smelting copper.
2. Build a wood and charcoal fire in a hole in the ground.
3. Pour malachite powder onto fire. See Figure 2.
Figure 2. Pouring malachite powder onto the fire.
4. Put a sod cap on the fire and employ bellows for several hours. See Figure 3.
Figure 3. The sod cap is the critical element in achieving 2200°F. The smelter had to work at the bellows for several hours.
The sod cap is the clincher. It holds the heat in and seems counter intuitive at first. But, it works.
This thing about all of this technology that fascinates me is how they had the endurance to keep at it. Surely, they failed many times. One would think that the first people to perfect the technique would have kept it secret from their neighbors, as the process would be an economic advantage.
Despite all of this importance that smelting copper provided to our success as a species, I couldn’t find anywhere online where the smelting of copper was considered a significant invention!
Finally, thank you to David Chapman at Ancient Arts for providing us with permission to use the photos above. You can see more images and smelting information on their website, ancient-arts.org.
Cheers,
Dr. Ron