IX: Saltpeter

The secrets of saltpeter changed history.

IX: Saltpeter
Freshly mined saltpeter. Photo by William Haun.

Good morning. Today is nonidi, the 9th of Nivôse, Year CCXXXI. We celebrate le salpêtre, a mineral that goes boom.

Saltpeter is potassium nitrate (KNO3) and was traditionally extracted from caves full of bat guano. Remember how bats were at the extreme "nitrogen-rich" end of the manure spectrum yesterday? This is why. While saltpeter can be used as a fertilizer, it's more frequently been deployed as a weapon. At first, its use as a weapon was just lighting it on fire as a crystal to produce a noxious smoke bomb that would chase people away. Then, beginning in medieval times, the Chinese figured out how its powdered form could be purified and combined with sulfur and carbon to explode. That's right, this week's minerals have been a sneaky ingredient list for how to make gunpowder.

Before oil, the natural deposit with the most strategic military importance in the world was saltpeter. While gold caused nations to do crazy things and go on far-flung expeditions, and spices led to the creation of rapacious mercantile operations, saltpeter was the source of much desperate political maneuvering and military strategy.

And the only saltpeter mines in Europe were in the mountainous Mediterranean regions of Spain, Italy and France. If you wanted to conquer the world with cannon fire from ship decks and muskets strapped to your back, you needed the output of those mines. Looking at late medieval history, it's obvious which regions had a head start.

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