Kelly - Gunpowder: alchemy, bombards, and pyrotechnics ; the history of the explosive that changed the world

... that puissant monarch,
Which rides triumphing in a chariot
On mist-black clouds, mixd with quenchless fire,
Through uncouth corners in dark paths of death.

BARNABE BARNES, 1607

FIRE IGNITES OUR dreams and our anxieties. It speaks to us in a language more basic than thought. Our instincts respond to the flicker of flame, to the wavering colors of the coals, to the roar of the conflagration.

Fire needs fuel, oxygen, heat. It needs an initiatora tiny bit of burning metal struck to white heat by friction against flint, a spark. The heat of the spark rips apart molecules of fuel. Carbon and hydrogen atoms combine with oxygen. The reactions are exothermicthey give off heat to ignite more fuel, a chain reaction. The complex process remains something of a mystery to science even today. We understand roughly what is happening, but the flame appears to have a life of its own. Its energy bursts out as heat, which makes particles of soot incandescent.

Mankind has lived with natural fire for eonsthe hearth, the campfire, the candle flame have been our intimates. Like human lungs, the flames are nourished by oxygen from the air. As convection carries away the hot spent gases, fresh air reaches the fuel. But oxygen makes up only 20 percent of the atmosphere. The thirst for oxygen puts a perpetual brake on natural flames. Winds fan a firesmothered, the flames die.

What if the fires heat induced oxygen to burst from the very pores of the burning material? The brake would be let offthe fire would burn unrestrained, with utter abandon. The chain reaction of combustion would accelerate at an astonishing rate. Instead of needing minutes or hours to burn, the fuel would go up in a fraction of a second.

This violent reaction, a product of inner oxygen, is mans fire, concocted, singular, unquenchable. It does not exist anywhere in nature. It is artificial firefeu dartifice, fuegos artificialesterms for what in English we call fireworks, pyrotechnics. Its embodiment is gunpowder.

Artificial fire requires an oxidizer, a chemical that emits oxygen when heated. Mix the oxidizer with the fuel. Grind it until the ingredients are in intimate contact. The oxidizer is saltpeter, the fuel a combination of charcoal and sulfur. As the fuel burns it decomposes the saltpeter, releasing virgin oxygen. The oxygen accelerates the burning, a process technically called a deflagration. You have created gunpowder.

The substance that was to be known as gunpowder was not invented for the gun. Before gunpowders inception, no one had conceived of a projectile-throwing machine driven by chemical energy. Humans developed tools for using this new material only after it had emerged from the fantastical speculation of alchemists. Only through centuries of trial and error did gunpowder reveal its properties and possibilities.

No rational theory guided the inventors of gunpowder. Whats more, during the nine hundred years when powder was in common use, indeed during the century since it has been rendered obsolete for most uses, no other combination of natural ingredients was found that could replicate its effects. Gunpowder was unique.

Early in its history, gunpowder was labeled the devils distillate. Onlookers were terrified by its flash and boom. Its fabricators were secretive, blackened men, daredevils whose arcane work was subject to disastrous accidents. One of gunpowders ingredients, brimstone, was the burning stone always associated with Satan. Gunpowders action was a diabolical mysteryonce ignited, it blazed wildly, infernally, leaving behind the sharp tang of sulfur and a haze of smoke.

Gunpowder, for most of a millennium, was mankinds only explosive. It was one of the few chemical technologies to emerge from the Middle Ages. Its effects were momentous. In the seventeenth century, Francis Bacon spoke of those three which were unknown to the ancients, and of which the origin, though recent, is obscure and inglorious; namely printing, gunpowder and the magnet. For these three have changed the whole face and state of things throughout the world. Gunpowder was indeed of inglorious origin, fashioned by craftsmen from the basest of ingredients. It was just as surely a catalyst of the modern world, an invention that threw up a divide beyond which the rivers of history flowed in a new direction.

Today, gunpowder is an anachronism. The powdermakers who operate the few remaining mills use methods that are centuries old. Their way of making powder would not be a mystery to an artisan of the 1300s. It is remarkable that a technology that arrived in the West in the time of Dante was still performing valuable service in the time of Henry Ford. A substance that was fueling skyrockets and firecrackers during the era of Genghis Khan will be doing the same during the era of the quantum computer.