First published in 1556, the book was written in a credulous age. It is only natural that Georgius Agricola should mention dowsing as a technique for finding valuable minerals. But he makes two very modern observations. Firstly, he says dowsing is a medieval technique that has no direct equivalent in classical times. Secondly, while some miners swear by dowsing, others regard it as completely useless.
His list of hazards applies equal to all ages, from ancient Greece to modern China. Miners are crushed by cave-ins and choke on dust. Chilled senseless, poisoned by arsenical fumes, or simply careless, they fall from ladders and break arms, legs and necks. They suffocate from poor ventilation and drown in sink holes.
Strangely, Agricola does not mention explosions. He is an expert in metals after all. Perhaps he has no experience of coal mines. Demons get only a couple of sentences. By contrast, he devotes a whole chapter to proper ventilation, sketching half a dozen schemes for forcing fresh air down a shaft. Mining is a hard school and there are enough real problems without invoking the supernatural. At least no 16th century miner ever died by electrocution!
The machines are the highlight of the book. There are dozens of winches, pumps and blowers, with axles, brakes, pipes, chains, buckets, toothed wheels and slotted collars. Just when I'm thinking that wood isn't strong enough for gears, he points out that these mechanical parts are made of iron or brass. This was the state of the art right up until the invention of rails and steam engines.
Agricola has clearly mastered the mechanical engineering. He is not so impressive when it comes to chemistry. He has copied passages from books on alchemy, probably without understanding it. (Mind you, the essence of an alchemical text is to impress the reader without giving away any secrets. They are designed to be useless.) His recipes for acids include some obvious duds, and he neglects to mention the distillation stage.
And so to law and finance. The ruler, the state and the landowner all want their cut, and if mining were easy, the miner would go to the wall. It is a capital-intensive business and rapacious princes have ruined many operators. I imagine that miners in the third world face exactly the same problems today.
However, no one gets paid unless someone works the mine, and if a miner is robbed it is unlikely that others will be keen to step in. In some areas, miners banded together to extort concessions, even winning the right to their own courts. (In England, these courts continued to protect miners right down to the 19th century and played a significant role during the canal boom.)
This is the first comprehensive work on mining in Europe. It covers every aspect from finding the seam to purifying the product, and despite the title it is not confined to metals. There is a chapter on extracting and purifying salts. It is a huge volume to begin with, and future president Hoover has doubled the size with his footnotes.