Originally published in Muzzle Blasts, March, 2007 --
I made a very exciting discovery while poking around in the basement of an abandoned house. The house was an antique colonial from around 1810; it was nominally owned by the Park Service, but in fact it had been unoccupied and unattended for many years. The ancient place was in a state of disrepair; and the fieldstone foundation had a crumbling hole on one side. I felt it was only my civic duty to make a tour of inspection of the historic building, and so I contorted my way through the badger-hole in the foundation wall, and I entered the dank earthy basement. What I found among the rough stones of the inside wall, gave me a shiver of excitement.
No, it wasn't a brittle leather sack stuffed with gold coins, that gleamed when you rubbed them with your sleeve. That's what I was hoping to find, of course, but it must have been too cleverly hidden. Also, I didn't even find an alcove that held a moldering oaken chest, bound with iron bands and a hand-forged padlock, filled with minted silver.
None of that, but what I did find, in the cracks between the stones, was an encrustation of powdery grayish-white material; with here and there some translucent brownish crystals. I found it more where there was mortar between the stones, and not as much where the stones had been laid dry. Examining the powdery deposits in the beam of my pocket-light, I thought, "Can this stuff be saltpeter?"
I had some sketchy notions of how saltpeter had been obtained in colonial days, for its use in the manufacture of gunpowder; the king's men would periodically rove through the countryside, breaking open stone walls to collect the saltpeter that accumulates inside them. I also remembered Poe's story, "A Cask of Amontillado," in which two men are deep within the catacombs of an old European city, and one man mentions the white webwork of "nitre" which they could see encrusting the damp stone walls. Nitre is the ancient name for saltpeter, or potassium nitrate. I thought it was a pretty good possibility that that's what I had just found. Gold would have been better, but this was interesting too.
So, I crawled back out of the hole, and I returned with some jars for collecting samples. I collected about 1/2 cup of the crystalline powder from between the stones, and then I headed back to my lab for some experiments.
To refine the samples, I put a stainless steel pot on the stove with about a quart of water, and added the powdery material. I boiled and stirred for a few minutes to dissolve out the soluble salts, let the sediment settle, and then filtered the liquid through a coffee filter. Then I put the clear liquid back into the pot, and boiled it away, which took about fifteen minutes. I was left with a brownish white crystalline residue in the bottom of the pot. This would be the saltpeter, if that's what it was. I scraped the stuff out of the pot with a wooden spatula, and I ended up with about a teaspoonful of the brownish powder.
The easiest way I had to find out if the material was in fact saltpeter, was to go ahead and try to make gunpowder with it. If the material was something else, the worst that would happen is, I'd waste my time making mixed dirt.
First I made some charcoal. Using a propane burner, I heated chunks of willow wood in a covered clay crucible, monitoring the crucible until it stopped off-gassing, then keeping it sealed until everything cooled. The third ingredient of gunpowder is sulfur, and for this I had to cheat and use store-bought from a lab supply, because I don't know of any natural deposits of sulfur in my location.
After grinding the ingredients separately in a mortar and pestle, I weighed them out in the correct proportions, mixed in a few drops of water, and ground the resulting paste in the mortar. Then I spread the black paste on a sheet of glass and left it to dry in the sun for a few hours. When the paste was dry, I lightly crunched it up into granules, about the consistency of very coarse salt. I ended up with about 6 1/2 grams of finished powder. This is about one hundred grains, in firearm parlance; enough for a musket-load, with some left over for priming.
Now came the moment of truth. I put a small amount of this stuff on a metal dish, applied a flame, and Foomph! It flashed up! It wasn't as fast as commercial power, but it actually worked!
In commercial production, the ingredients of gunpowder are milled together for several hours, always being kept moistened to prevent accidental ignition. I milled my batch for only a few minutes, but it performed well enough for proof-of-concept. The samples I had collected in the old basement probably contained a combination of sodium nitrate and potassium nitrate, because my powder burned with a softer, yellower flame than ordinary powder: a sign of sodium.
For my final experiment I wanted to load up my big .68 caliber flintlock pistol to try out the powder, but I didn't have enough powder left for a proper load in that. So I used a .45 cal. caplock pistol, which would work better with a smaller charge, although I would have preferred the flint ignition. I loaded the pistol with about 25 grains, a little under 2 grams, of my concoction, (most of what I had left), then wrapped a .44 lead ball in a greased cotton patch, rammed it down over the charge, and placed a percussion cap onto the nipple.
With the loaded pistol on half-cock, I carried a couple of phone books outside, and propped them against a stump. Then I presented the piece, brought the hammer to full cock, and squeezed the trigger. When I felt that pistol kick and heard the boom, I was quite pleased; I had made functional gunpowder from found materials! I felt I was one step closer in kinship to the ancient ways of our colonial forbears, whose self-sufficiency and resourcefulness I have always admired.
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