Gunpowder: From Alchemy to Empire with Jack Kelly

0:04 Welcome to AMSEcast, coming to you from Oak Ridge, Tennessee, a global leader in science, technology, and innovation. My name is Alan Lowe, director of the American Museum of Science and Energy, and the K-25 History Center. Each episode of AMSEcast presents world-renowned authors, scientists, historians, policymakers, and everyone in between, sharing their insights on a variety of fascinating topics. Welcome and thanks so much for joining us on AMSEcast. I’m very pleased to welcome our guest today, Jack Kelly. Jack is a New York Foundation for the Arts Fellow, and an award winning historian, journalist and novelist.

0:47 He’s written for publications like the Wall Street Journal and American Heritage, and you may have heard or seen him during appearances on NPR, PBS, and the History Channel. Some of his many books include Heaven’s Ditch: God, Gold, and Murder on the Erie Canal; God Save Benedict Arnold: The True Story of America’s Most Hated Man; and the book we’re going to discuss today, Gunpowder: Alchemy, Bombards, and Pyrotechnics: The History of the Explosive that Changed the World. Jack, welcome to AMSEcast. Well, thank you very much, Alan. I so enjoyed this book. It’s really fascinating from beginning to end. Let’s start at the beginning. The Chinese invented gunpowder.

1:28 They first created it. When did that happen? And then when did it make it to Europe? The first gunpowder is really developed around 1000 AD. That’s a good date to pick. There was actually a piece of writing from 850 AD that was a warning. And the development of gunpowder in China was mostly done by Alchemists, and unlike in the West, where the alchemists were looking to change lead into gold, in China, they were trying to develop an elixir of long life, and they tried mixing together various chemicals that they thought would have this purpose. Some of them were deadly poisons, but they didn’t know that at the time.

2:08 And there was a warning that was written down in 850 AD, “Watch out if you combine these various ingredients because they can explode or they can flame up.” And so, that was thought to be the first reference really, to anything like gunpowder. By 1044 AD, they had, already, recipes for gunpowder. And it was referred to as the fire drug, or the fire medicine, which gives a kind of clue into the origin of it. So, what are those basic ingredients? One of the really fascinating things about gunpowder is that all the ingredients—the three ingredients, I should say—are naturally occurring. You can find them in nature.

2:48 And the other thing I think that’s worth keeping in mind when we talk about gunpowder, is that gunpowder is a mixture of these ingredients. It’s not a chemical in itself. It’s sort of like a salad, where you have the lettuce and the tomatoes. You can separate them out, but they’re all mixed together. The first and most important ingredient in gunpowder is saltpeter. That makes up about three quarters of gunpowder, and it’s a naturally occurring salt that could be found in various places. Charcoal makes up 15%, and that’s simply the same type of charcoal we use in a barbecue reduced to a powder, and then sulfur makes up the remaining 10%.

3:29 And that we use—it’s scraped from the openings of volcanoes, and there’s other sources of sulfur. So, those are the three ingredients, and have remained in those proportions for pretty much 900 years. And that was the only explosive known to humankind for all those centuries. So, quite a unique invention back in 1000 AD. Really unique and really world changing, as you show. Saltpeter, you mentioned, is a significant part of that recipe. Why has it proved to be a challenging component to produce? Why was it hard to produce for folks around the world? There was really two sources of saltpeter, and one of them was in a climate where you had a very heavy rainy season and then a very hot dry season.

4:21 And during the rainy season, the saltpeter would be produced by the action of bacteria on organic material. The bacteria would essentially eat the organic material and give off this nitrate. During the dry season, those nitrates would leach up to the top and precipitate out and form a crust on the surface of the soil. That occurred mostly in India, and India became a very big source of saltpeter. It had to be scraped off from the soil and then refined to make what they needed, but it was the source of saltpeter. Whereas in Europe, if anybody who’s a gardner knows that you create a compost heap, you’re trying to create fertilizer for your garden, and that fertilizer is also nitrate.

5:09 And so, in Europe, they would either dig up barnyard soil or old privies they’d find where there’s a lot of organic material. Or eventually, they started these farms where they would have ditches full of organic material and deliberately produce, in essentially a large compost operation, the nitrate, which then had to be carefully dissolved in water and refined into a powder. But because it was the largest, the most important ingredient in gunpowder, it was always in short supply. Now, you mentioned, when gunpowder made its way to Europe, it wasn’t really—the making of the gunpowder wasn’t really a scientific process, but more of an engineering, almost trial-by-error [laugh] process.

5:55 What were some of the challenges that confronted those early engineers with the production of that gunpowder in Europe? First of all, chemistry was a very late science to develop, and I think it’s obvious why. If you compare it to physics, with physics, you had the actual objects. You could see things hitting each other, or two weights dropping, whereas with chemistry, everything was invisible. And even today, even with electron microscope, we couldn’t just barely see a molecule because it’s so tiny. So, everything in the development of gunpowder had to be through trial and error. And it was amazing that they developed, really, the formula that lasted for 900 years through this trial and error.

6:36 And the other thing that was an obstacle to making gunpowder was that you didn’t just mix the ingredients together; they had to go through a process, what they called incorporation. And that was essentially they would take the powders, these three powders, mix them together in the right proportions, and then moisten them with either water, or sometimes they thought that urine or wine or something would give it more power. They would moisten it into a kind of putty, and they would put that in a mortar and pestle and pound it for 24 hours, completely integrate the three ingredients together.

7:16 They still remained separate ingredients, but they intimately mixed together. Later, they developed a more industrial way of incorporating the powder with these giant rollers that would roll over platters filled with this moist gunpowder. But those were the challenges that they had to overcome to really—and gunpowder really did develop slowly for many centuries, you know, just increasing the power and the reliability and the consistency of it. Seems like there’s a good amount of danger built into that process, though. Yeah, that was always the case. The gunpowder mills tended to blow up quite easily.

7:58 I actually went out to see what was the last gunpowder mill in America—I think—when I was writing the book, and I asked the proprietor, I said, “How did you get past that danger aspect of it?” Because now they have OSHA and all these workplace regulations. And he said, “We never did.” And he said, “They’re still a dicey operation.” And ironically and really tragically, about a month afterwards, they did have an explosion there, and two men were killed. And they were probably the last, hopefully, of a long list of men who died making gunpowder over the years. When science did develop, when the science of chemistry developed, what did it reveal about how gunpowder works?

8:42 Each of the ingredients has a specific role. And the saltpeter, the role of the saltpeter is to produce oxygen from within the powder. The saltpeter is potassium nitrate. The nitrate radical—what they call the nitrate radical in chemistry—is a nitrogen atom with four oxygen atoms attached to it. It’s a very unstable radical, and when it gets hot and starts jiggling around, the oxygen flies off. That is the key to why gunpowder works because the oxygen, for the combustion of the charcoal and the sulfur, is inside the powder.

9:23 The charcoal burns at very high heat, produces a lot of hot gas, and sulfur, in the contrary, burns at a relatively low temperature, so that speeds up the reaction. I always try to compare it to a candle. If you light a candle, the hot gasses that are coming off the flame will suck in oxygen from the air—suck in air, actually—to make the burning continue. But air is only 20% oxygen. In gunpowder, you have all the oxygen you need contained within the actual substance. So, speed is everything. The whole gunpowder reaction takes place in about three one-thousandths of a second.

10:08 So, it’s just a blink of an eye, and it’s all burned up and turned into this hot gas. I sometimes compare it to, you know, burning a piece of charcoal. There’s actually more energy, more heat, in a charcoal briquette than in an equal amount of gunpowder, it’s just that, with the briquette, it burns over half an hour, and the gunpowder, it goes off instantaneously. And with the briquette, I can never get them lit, but that’s another matter altogether. So [laugh] . They always seem to be at the perfect—just getting to be perfect temperature when you’re done cooking. [laugh] That’s right. I never understand that either. So, I found it really interesting that as gunpowder developed, men like Galileo were looking at it, it helped really inspire new ideas in areas like combustion, mechanics, forces of motion.

10:57 Can you talk a bit about that? There was a great incentive to study and to improve gunpowder because it was so essential to the power of the various countries that were using it in warfare. They developed the chemistry of it. For example, Lavoisier was a famous chemist in France in the 18th century, and also was the man who directed their gunpowder operations. So, he brought in a lot of improvements to making gunpowder. He understood what was going on better than the craftsman of earlier times, and he particularly got past the idea that the fire was a substance inside of a fuel.

11:39 They thought that a block of wood had this phlogiston, as they called it, inside it, and it was let out when it burned, and of course, that was not the way that it worked. As far as physics go, gunpowder weapons I should say, were very influential in physics. There was a gentleman in the 1500s who was studying what’s the best angle to aim a cannon to get the longest range in the cannonball, and he tried to look at it mathematically as well as it could. And he found that, for example, if you fire it exactly parallel to the earth, it still curves downward. Why is that?

12:19 You know, now it seems so obvious to us, but they started asking, why does it do that? And that developed—through Galileo, who came a little bit later—into the idea of gravity, inertia, acceleration. And the guns were an incentive to study all these aspects. And eventually you get to Isaac Newton, who really took the cannonball and compared it to the moon and the planets and unified the science and totally transformed science. Mentioning guns and cannons, when do you see those appear on the scene? One of the interesting myths about gunpowder is a lot of people say that the Chinese, they discovered gunpowder, but either they were so wise that they didn’t use it for warfare, or they were so dumb they didn’t see how they could use it for warfare.

13:09 Both of those things are wrong. They used it very extensively for warfare, and they developed flamethrowers and rockets and bombs and landmines. When it got to Europe a couple centuries later, the Europeans focused mainly on the gun. They didn’t get going for the more exotic weapons of war that the Chinese had developed. And the first guns were used in battle, I think pretty much assumed, in 1346. Edward III on one of his conquest of France, he fired off guns. Very ineffective, but it created a big sensation. It was sort of a psychological weapon almost. By the 1400s they began to develop larger and more efficient cannon.

13:51 Mehmed II in 1452 used a cannon to break down the walls of Constantinople and end the Byzantine Empire that had been there for many, many centuries. So, they were beginning to be then, very effective by that time. A lot of folks don’t realize, the Roman Empire really didn’t end until the 15th century, and it ended thanks to those cannons, yes. So, you talk about the impact of these new weapons, powered by gunpowder, on government-owned social structures. Can you talk a bit about how that started transforming those in Europe? As they developed a larger and larger cannon, their main purpose was not to kill people, but to break down fortifications. And by the 1450s they had 16-foot-long cannons shooting two-foot diameter balls into the walls of castles.

14:41 That destroyed the base of the nobility during feudal times. And they couldn’t hide in their castle anymore, and they didn’t have the money that the king had in order to buy the guns, very expensive, the powder was very expensive, and the fortifications that you needed to protect yourself against cannon fire were much more expensive than building a castle. So, the feudal age then died out and gunpowder was one of the things that contributed to that. The other aspect was that using what was called, originally a hand cannon, or later a musket, a peasant could fire a ball and pierce the armor of a knight.

15:25 And the knights had ruled for many centuries, the knight on horseback in his armor was sort of impenetrable, and they suddenly became obsolete as well, so the possibility of power being taken up by common people who didn’t need a lot of training, they just needed to have a gun and fire it, really transformed the dynamics of society as well. And also, as you show, helped lead to the spread of empire as well. We have to look at gunpowder as a form of power. And in the days of, for example, of Alexander the Great, to exert your power, you had to send an army. And the army was expensive, you had to transport the troops, you had to pay them, you had to feed them.

16:07 With the gunpowder, you had the power concentrated in a ship. And you had cannon on the ship. You would take it out, as Vasco da Gama did to India, and threaten to blow down their buildings, and they would then come to a conclusion that was made more sense to trade with you on unfavorable terms. And so, that was the way that Europeans spread their power out through India and Africa, the West, the East Indies, and then around the world. Now, we’ve talked about gunpowder in the context of war and conflict, but it started to be used for more economically productive ways. What were some of those, and why did it take so long for it to get to these more peaceful ways of using gunpowder?

16:52 It was slow to be used what I would call generally blasting instead of use in weapons, partly because gunpowder was so expensive. It was not seen as—these were practical enough uses to use this very valuable material. It was dangerous. It was, just tradition continued on, and people didn’t want to change. But eventually they did see that gunpowder could be used for making canals or for drilling tunnels through a mountain or for mining. It became very big use of gunpowder, for mining. When we get into the 1800s and gunpowder began to be produced on an industrial scale, these uses really blossomed.

17:38 And if you look at the overall history of gunpowder over the many, many centuries, there was more gunpowder used for peaceful purposes and for blasting than was used in all the wars because the wars used a huge amounts of gunpowder, but only for a few years at a time. Year in and year out, they were producing a lot of gunpowder to do what was basically civil engineering jobs. Interesting. I know in your book, and I don’t mean to not go into all the details, but I want our listeners to read the book if they haven’t already, you talk about a whole host of different types of weapons and ammunition, but we talked a bit before we went on air today, about the Minié ball—if I’m saying that correctly—of how that transformed or helped transform warfare.

18:20 Can you tell us a bit about that? I actually have written a number of books about the Revolutionary War, and during the time, and for a long period of time in the development of muskets—the musket was a smoothbored weapon, I should call it—and it was very inaccurate. They didn’t even aim muskets; they would just fire in a phalanx of muskets and hope that some of the bullets had effect. And the reason was that it was not rifled. And the rifling was a way of spinning the bullet in a predictable way, and it would go in a completely straight line. That was the idea of the rifle. But the rifle was a very slow weapon to load, so they thought that firing more quickly with the musket, the smoothbore musket—the trouble was, of course, you always had to reload in between the shots, but that remained.

19:15 By the Civil War, they had this idea of the Minié ball, which had a hollow in the back of it, and it was more like a modern bullet as opposed to a ball. And that hollow would spread out and it would catch the grooves in the barrel of the gun and deliver that spin. It was still a muzzle loader, but it was much more accurate out to quarter or half a mile. And a lot of the destruction, a lot of the fatalities in the Civil War were because their tactics were had been developed during the time of the musket, but when the Minié ball had come in, and these rifled muskets came in, with their accuracy, they were able to mow down troops and Pickett’s charge—and I talk in the book about Pickett charge is just one of the great tragic results of that.

20:03 As I mentioned to you previously, I was director of the Lincoln Library Museum in Illinois for a while, and certainly that weapon has used a devastating effect during the Civil War. Let’s talk about the age after gunpowder. So, what has replaced gunpowder and weapons and other explosives today? If you were to point to one person who brought down this 900 years of technological supremacy of gunpowder, it would be Alfred Nobel. I wouldn’t call him a scientist. He was an engineer, a Swedish engineer, quite knowledgeable about chemistry, though, and he found a way to use nitroglycerin for the type of blasting projects that we were talking about a minute ago.

20:45 And nitroglycerin was a synthetic product made in a chemistry lab using glycerin and treating it with acids. It was highly explosive, but it was hard to figure out exactly how to set it off. And he came up with the idea of the blasting cap—which was really his most important invention—of using a little tube of gunpowder that could be set off with a fuse to create a shock that would set off the nitroglycerin. He started a whole industry of selling nitroglycerin. The problem was that the nitroglycerin got to be—it could easily go unstable when it was being shipped or stored and explode spontaneously, which you didn’t want to happen, of course.

21:32 So, he went back to the drawing boards, and he found that if he took the nitroglycerin and absorbed it in clay, and then took that clay and formed it into sticks wrapped with paper, that it was stable and he could still set it off with the blasting cap. He called it dynamite. And that was the end of the blasting off with gunpowder because dynamite was easier to make, it was more reliable and it was much, much more powerful. He invented that in 1867 and by the end of the 1800s, gunpowder was pretty much obsolete. The other use for gunpowder was as a propellant to shoot bullets out of a gun, and that use was taken over by nitrocellulose, or what they call guncotton when they invented it.

22:21 And the big advantage that had was it was just as powerful as gunpowder, but it didn’t produce the smoke that had always been a problem with gunpowder. If you ever see a reenactment of Revolutionary War or Civil War battles, there’s always a lot of smoke, and that was a product of gunpowder. So, they called this new powder, smokeless powder, and gunpowder became known as black powder and reached the end of its useful life, I’d say. Is black powder used in anything today? Well, it’s still used in fireworks. There’s certain aspects of fireworks, the lift charge that throws the mortars up into the air.

23:03 It’s used in reenactments. It’s very popular among Civil War and Revolutionary War reenactors. Muzzle-loading hunters use it. Gunpowder continues to be in heavy use in certain quarrying operations, particularly slate and marble, where you don’t want to shatter the rock, you just want to split off sections of it, and dynamite would be too powerful for that, and would tend to totally shatter the material. Those are relatively minor compared to the vast use of gunpowder in the 19th century, and I think you can effectively say that gunpowder is obsolete today.

23:43 This one thing I’ll have to note, I had no idea that there still were musket hunters. That’s amazing. I had no idea. Yeah, they have a season that extends beyond the regular season for muzzle-loading guns, yeah. And just as an interesting thing, they’ve now developed a substance called Pyrodex that these hunters use and the reenactors use as well. That’s essentially smokeless powder, with a another chemical added to create smoke. It’s less corrosive and it’s more reliable than the old black powder, but it still looks like black powder. Interesting. Well, I’ve been to several of those reenactments, including Gettysburg, and that’s I’m sure, I assume, then they’re using that new thing.

24:25 That’s interesting. Jack, you have so many interesting books. What are you working on right now? What’s next for you? The last few years, I’ve been specializing in books about the Revolutionary War, and of course, we’re now in the 250th anniversary of the war, and next year is going to be the culmination. I thi—I’m hoping there’ll be a lot of interest in the 250th anniversary of the birth of the country. And I have a book coming out in January of 2026 that’s about Thomas Paine and his role in the revolution. He’s noted as a thinker, and he wrote the famous essay that, “These are the times that try men’s souls,” but a lot of people don’t realize that he was also a soldier, and he marched with Washington’s army during 1776 and was really involved in the action in a very crucial time for the country.

25:15 So, I refer to him as the founder for our time, and I think his ideas are well worth looking at again. Absolutely. I’m really interested. I can’t wait to read that. I will tell you right now at AMSE, we have an exhibit all about President science and engineering, and the story we tell about George Washington is when Paine came to visit him while they’re waiting on the treaty to come back from France, and they do a little experiment on the river in New Jersey to see why it catches on fire. And it’s really fascinating to see that interest in science early on from our founding father, George Washington, along with Mr. Paine. They were all men of the Enlightenment, and the Enlightenment was—science was their guiding compass, so yeah, that’s not surprising.

25:58 So, thank you again, Jack. Really enjoyed our conversation. Thank you so much. Yeah, same here, Alan, and best of luck. Thank you for joining us on this episode of AMSEcast. For more information on this topic or any others, you can always visit us at AMSE.org or find, like, and follow us on Facebook, Instagram, and Twitter. I invite you to visit the American Museum of Science and Energy and the K-25 History Center in person. You can also shop at our online store and become a member at AMSE.org. Thanks to our production team with Matt Mullins, plus our supportive colleagues at the Department of Energy’s Office of Science, Office of Environmental Management, and Office of Legacy Management, as well as Oak Ridge National Laboratory, the Y-12 National Security Complex, NNSA, and the AMSE Foundation.

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