“War! war! war! was the cry, and it was pronounced in a tone which would have done honor to the oratory of a Briton or a Roman.”
—John Adams1
The Method of Refining Salt-Petre, illustrated by Paul Revere
In the predawn hours of September 1, 1774, a battalion of British regulars rowed thirteen boats three miles up the Mystic River, marching to the Provincial Powder House located in what is today’s Somerville. The soldiers had been deployed by Major General Thomas Gage, the British commander in chief of North America, who had reasoned that preemptively getting hold of as much black powder as possible would help defuse the potential insurgency brewing among the colonialists. According to British law, every town in Massachusetts could legally use the regional magazine to house their gunpowder. As tensions mounted, numerous towns began withdrawing their allotted amounts as a precautionary measure against British confiscation, including from the Boston magazine. In turn, fearing that militias would forcefully raid the Crown’s supply, Gage began planning ways to secure the powder for safekeeping.
Both of these fears were well warranted.
The cone-shaped, stone-cobbled structure the powder was stored in, which still stands today, was first erected in the early 1700s as a windmill. If the British soldiers had bothered gazing up at the building’s roof as they marched up the hill, they would have noticed one of Benjamin Franklin’s famous lightning rods—and for good reason. The building had been converted into a gunpowder magazine only after local Bostonians protested that such dangerous munition should not be stored near their homes.
Unlike modern powder, the black powder of the late eighteenth century was hazardous and highly volatile. A number of major European cities, including London, had experienced devastating fires due to accidental explosions in inner-city powder houses. Early Americans did not pass laws limiting gun ownership, but they were not above nudging citizens into protecting cities from hoarders of gunpowder. One typical late eighteenth-century regulation in New Hampshire, for example, offered that gunpowder “greatly endanger[ed] the lives and properties of the inhabitants thereof in case of fire; which danger might be prevented . . . the owners of such powder [were required] to deposit the same in the magazine provided by said town for that purpose . . .”2
It was not surprising, then, that the British soldiers who arrived in the dark early hours that morning were forced to wait until full daybreak before removing the bounty lest they blow up the storehouse with their torches or a random spark. By mid-morning, however, Gage’s men had surreptitiously removed 250 barrels of gunpowder from the public storehouse and rowed back to Boston. At the same time a small detachment of soldiers wound their way through the town of Cambridge to collect two additional field pieces from the local armory. All the items were transferred and stored in the British fort on Castle Island in Boston Harbor.
While the mission itself had been a success, the long-term prospects of confiscating powder would have disastrous consequences for the British. The people of Boston were already agitated by the possibility of the occupiers attempting to disarm them. Once evidence emerged that there had been a conspiracy to do so, the threat of violence loomed.
A few days before Gage sent troops to the Provincial Powder House, William Brattle, a wealthy Bostonian who had long played both sides of the Tory-Patriot debate, hatched an idea. Whether he was eager to avoid violence or simply a Loyalist at heart, we can’t know, but Brattle penned a letter to Gage warning him that it was conceivable American plotters might steal gunpowder and bolster the strength of local militias. He went on to offer, in great detail, information about the contents of the munitions that were housed in the magazine—and then gave Gage the keys.
Gage, either by accident or for some undetermined political reason, dropped Brattle’s letter from his pocket in the streets of Boston. It was fortuitously recovered by an American patriot and published in the city’s newspapers the day after the raid on the Provincial Powder House, infuriating the local population. Brattle, whose life was now in danger, escaped the city, claiming that Gage had demanded an inventory of the magazine and the key. Whatever the case, the inflammatory news spread quickly throughout the region. “This,” wrote Abigail Adams to her husband John, who was in Philadelphia at the time, “has so enraged and exasperated the people that there is great apprehension of an immediate rupture.”3
Soon wild rumors about British atrocities against colonial townsmen also began spreading: war had broken out, militiamen were being gunned down, and the British were bombarding Boston with their warships. One visiting Irish merchant staying in a tavern around thirty miles outside Boston recalled being woken in the middle of the night by a violent banging at the front door. Agitated voices outside told a dramatic tale of powder being taken with “six men killed & all the people between there & Boston arming & marching down to the Relief of their Brethren at Boston.” The merchant added that he had never seen anything like it, with “fifty men collected at the Tavern, tho’ now deep in night; equipping themselves & sending off Posts every Way to the neighboring Towns.”4
It wasn’t long before thousands of these New Englanders clustered in large groups across the region, many of them moving toward Boston. A reported 4,000 headed toward Cambridge’s Tory Row, the name given to Brattle Street where Loyalists lived. In towns around Boston, locals quickly took control of the militia from the Crown.5 The reaction was widespread and impressive and portentous. And as the reality of the situation hit Gage, he wisely abandoned a plan to confiscate gunpowder that was housed forty miles away in Worcester. Once the colonists began to learn that the accounts of British carnage had been merely gossip, the situation decompressed.
Why all the drama over gunpowder? To understand the colonists’ concerns, we have to jump ahead for a moment. It’s important to remember that the dearth of black powder would be one of the persistent anxieties of colonial leaders before and during the war. Finding it, buying it, and producing it would be a constant headache. One of the first topics taken up by the Second Continental Congress, in fact, was gunpowder shortage.
When war broke out, the shortage fears of revolutionary leaders was felt immediately. The nascent militia-army at the Battle of Bunker Hill had been unable to repel British advances because lack of gunpowder had inhibited the militia from properly training with cannons before the war. Ultimately, this meant hand-to-hand combat and retreat. The carnage that was inflicted on the British by Colonel William Prescott’s men in redoubt on Breed’s Hill, one of the first battles of the war, was even more impressive when we consider the small amount of gunpowder available to the Americans. The British general Sir Henry Clinton noted in his diary that day, “A few more such victories would have shortly put an end to British dominion in America.”6 Yet, by the end of the battle, colonialists had so little powder left that they were forced to wait until Welsh grenadiers, who made their methodical and deadly march up the hill in spite of massive casualties, were within thirty feet before shooting to ensure that they did not waste a grain. Had the rebels been in possession of more gunpowder, the battle—and perhaps the trajectory of the war—might have had a very different outcome.
According to an inventory commission by George Washington a few months after Bunker Hill, the Americans possessed less than forty tons of black powder.7 Some of the cache would supply troops who had surrounded the British in Boston, and much of the rest was taken by Benedict Arnold, then a highly regarded general, who participated in the attack on Fort Ticonderoga in upstate New York. When Washington reviewed the situation on August 3, 1775, he found there wasn’t enough powder for each of his men to carry half a pound each. And there was almost none left for his cannons.8 By the end of the first nine months of war, practically all the gunpowder had been used up. “Our want of powder is inconceivable. A daily waste and no supply administers a gloomy prospect,” Washington wrote in December 1775.9 If General William Howe, who arrived in the middle of the Siege of Boston, had known about the shortage of supplies, he might have been able to burst out of Boston and end the Revolution right there.
In many ways the run on powder was the true start of the Revolution. This was the moment that American leaders made their first concerted efforts to marshal military forces to stop the British. Although the Americans were driven by idealistic beliefs, protecting the powder was a practical concern. There was, need it be said, no way to defend your beliefs in natural law, the right to self-defense, or personal liberty without the ability to pour powder into your musket.
How was it that the American colonies, a place with vast natural resources, teeming with firearms, and populated by an individualistic population that already prided themselves on self-reliance and innovation, could find itself in such a predicament? It’s complicated. Although modern Americans do not concern themselves with shortages of weapons, much less gunpowder, it’s worth understanding how the substance found its way to colonialists at the dawn of war.
Incendiary substances had been utilized in warfare going back to at least the ninth century BC. Perhaps the most mysterious of the early flammable weapons was developed in the seventh century by the Byzantines. “Greek fire” was used to protect Constantinople from Arab siege. While we still don’t know for certain the formula for Greek fire, it was likely a base of distilled petroleum—with saltpeter added to intensify combustibility, according to some sources. The solution was said to have stuck to whatever it hit, incendiary or not, and water could not extinguish it. The mix, delivered in packages launched by catapults or slung by soldiers, would burn the hulls of ships and have disastrous consequences for those attempting to jump overboard.10
By the mid-1200s, all mention of Greek fire comes to an abrupt end. It’s possible that the formula, known only to the upper stratum of the By-zantium leadership, was lost in a palace upheaval and forgotten. Or, more likely, a more effective alternative had already come along to replace it, because, by the 1300s, we know that Muslims were already using their own incendiary devices against Christians in the Holy Land. It was a brew that had come to them by way of Asia. And until the middle of the nineteenth century, gunpowder remained man’s only known chemical explosive.
It was the Chinese Taoists, keenly interested in purification and chemical amalgams, who had been studying saltpeter (potassium nitrate), a substance formed by the decomposition of organic matter. All three of the ingredients that make up gunpowder had been used in medicinal combinations with varying levels of success over those years. This new grayish powder these experimenters cooked up did something that man had never seen before: it didn’t just burn; it blew up.
The invention of gunpowder was based on empirical observation, trial and error, and luck. Its inventors knew nothing about the chemical qualities or underlying science of explosions or propulsion. How does black powder work? Fire is a chemical reaction that is contingent on the presence of three things: oxygen, fuel, and heat. Simply put, sulfur and charcoal act as the fuel, and the saltpeter as the oxidizer. When saltpeter decomposes at high temperature, it provides the oxygen for the reaction. This means that gunpowder doesn’t need to be exposed to air to burn. This is why smothering fireworks won’t stop them from exploding and why the mixture would work in a metal tube.
Gunpowder typically consists of 75 percent saltpeter, 15 percent charcoal, and 10 percent sulfur. When lit, it emits 40 percent gas and 60 percent solid, in the form of smoke and residue. If you put gunpowder in a confined space, the pent-up gas will look for ways to escape and in the process propel objects that get in its way: ammunition like bullets or pottery or stones. The explosion produces a flash, white smoke, a sulfurous odor, and a loud bang. As millions of soldiers would be able to attest in the coming centuries, it is an assault on all the senses. Quality gunpowder later consisted of various other components that improved both combustibility and reliability, but the basics had been discovered. And whoever it was that first figured out how to propel objects using this powder had changed history in incalculable ways.
The Europeans took this technology and adapted it most successfully for war. We will never know with any certainty when the West was first introduced to gunpowder. It’s possible that various weak forms of the concoction had been employed by professional magicians conjuring colorful smoke and noise for their audiences for centuries without understanding its potency. Whatever the case, early European gunpowder was at best erratic, weak, and unreliable. And unlike the Chinese, Europeans had a far more difficult time finding the needed ingredient, saltpeter, an organic component that occurs naturally only in unique conditions where the environment animates development of the necessary bacteria. Moreover, there are two kinds of saltpeter: one is calcium nitrate, the other potassium nitrate. The former is more abundant, usually found on manure, but makes a bad-quality gunpowder, as it absorbs water more easily. And a moist gunpowder is useless.11
So Europeans had to figure out ways to manipulate nature to meet their needs. The first saltpeter “plantations” were opened in Frankfurt in the 1380s, but they would soon be found throughout Europe. The process entailed dumping straw, leaves, and barnyard garbage into a pit or cellar and then marinating the entire mix with urine for a year. This repugnant blend was then dug up, strained, washed, and boiled to make saltpeter.12 Nearly anyone looking to make some extra money, and willing to live with the inhospitable stench that the cocktail produced, could brew some homegrown saltpeter.
As the need for the powder grew, entire mass-producing plantations began to pop up to supply the busy armies of Europe. At first, the powder itself was created by simply grinding up the three ingredients and mixing them together. This method was sometimes dangerous and often fruitless. Even if the combination was proportioned properly, if packed too tightly, it would fizzle and if packed too loosely, the components would separate and make the concoction useless. Soon gunpowder makers began mixing the components with water to create a slurry that was set on sheets to dry. When the saltpeter dissolved into the water, it would enter the porous charcoal component of the mixture, making separation less likely.
The resulting hard cake was more resistant to moisture, would last far longer in storage, burn more quickly, and increase the ballistic power of weapons. Europeans utilized crushing devices to grind the ingredients into uniform grain sizes that helped shooters calibrate gunpowder to their weapons. Early musketeers, for example, often used medium-grain gunpowder to shoot and fine-grain gunpowder to prime their guns. Cannoneers, on the other hand, used large-grain powder, which took longer to ignite. A more standardized process made production more stable and provided big advances in quality control.
Despite the improvements, gunpowder remained a perishable commodity in the best of circumstances, spoiled by dampness and clumping, or by agitation that turned grains to dust. The wooden barrels in which it was stored and shipped contributed to the problem. The saltpeter in the powder dried out the staves, opening seams and allowing moisture to penetrate. It was not uncommon that more powder was spoiled than was used.
This is what gunpowder looked like to the would-be revolutionaries in North America: often dangerous, often ineffective, often difficult to procure, but always a necessity. During the French and Indian War of the 1750s, a number of frontier entrepreneurs began running low-production mills, but none of them survived long. Once hostilities against the French ended, the British dissuaded colonists from trading or making black powder, closely controlling its manufacturing and importation. Not that they needed to apply much pressure, since the British imported low-cost high-quality product to the colonies, rendering inefficient operations economically impractical. British gunpowder was cheap and it was good. The problem was that the colonists had to rely on their soon-to-be enemies to sell it to them.
Before the Revolution broke out, there was really only one consequential producer of gunpowder in North America, the water-powered mill in Frankford Creek, north of Philadelphia. Oswald Eve, a prosperous English-born Quaker, had opened the mill only a few months before King George III banned exportation of gunpowder to the colonies in 1774. The place became something of a tourist attraction, as colonists visited to catch a peek of how gunpowder was made, often hoping to take back the secret of making it themselves.13
The Provincial Congress in Watertown had asked the silversmith Paul Revere to visit the mill in 1774, for “in Philadelphia powder mills are Erected and the manufacturing of powder is carried on with Considerable dispatch and advantage.”14 Revere anticipated replicating the operation in Massachusetts, but Eve was less than helpful when the two met, perhaps realizing that facilitating a competing mill was bad for business. That didn’t stop the perceptive Revere from taking a good look around and sending detailed sketches to Sam Adams. A plant in Canton, Massachusetts, was soon opened. It would produce a modest quantity of powder—that is, before it blew up in 1779.
The Americans also experimented with state-owned and-operated mills. In February 1776, with congressional approval, Pennsylvania began plans for the operation of mills that produced about a ton of powder weekly. By April 1776, the nascent government had built a gunpowder mill and a gun factory (added in December 1776) on the outskirts of Philadelphia. At its peak, the site was producing approximately two tons of gunpowder each week, and hundreds of locks for Continental muskets. Threatened by advancing British forces in late 1777, the majority of the military stores and supplies were removed from the site under orders from George Washington and moved inland to Lancaster County, the capital of American gunsmithing. Days later a detachment of Hessian Field Jäger Corps and British light infantry destroyed the buildings and remaining military stores.15
American military leaders often groused about not only the lack of gunpowder but also its inferior quality. Washington sarcastically noted that “there must be roguery or gross ignorance” in colonial powder-making efforts. In truth, it’s unlikely to have been either corruption or stupidity. Unlike Europeans, who had been producing gunpowder for centuries, colonialists had little tradition in the craft, and it showed. Without the quality Indian saltpeter the British used, American powder was sure to remain inferior. Before the war, most saltpeter was procured from the limestone caves in Virginia, Georgia, Tennessee, and Kentucky.16 This would not be nearly enough.
To assist production, the Americans established depots in New York and Philadelphia for the collection of saltpeter and sulfur. In January 1776, the Pennsylvania Committee of Safety placed ads in Philadelphia newspapers announcing that “such persons as are willing to erect Powder Mills in this Province, within fifty Miles distance of this City, are desired to apply to the Committee of Safety, who will lend them Money, on Security, if required, for that purpose, and give them other Encouragement.”17 It received six proposals from Americans willing to build mills. Very little came of the projects.
A Royal American Magazine piece in 1774 (illustrated by Revere) offered a step-by-step process of powder production at home. In the piece, the author claimed that saltpeter was “an effluvia of animal bodies. Pigeon houses, stables, and barns, but especially old walls, are full of it.”18 The Second Continental Congress, which also recruited French experts to teach Americans homebrew production methods, promised to buy up all saltpeter at half a dollar per pound. And once hostilities had begun, committees of safety in nearly every colony offered fiscal incentives to spur the production of saltpeter and pamphlets offering detailed instructions on its fabrication in hopes of spurring a local saltpeter industry. Yet this method could be an arduous process that yielded only small amounts of subpar saltpeter.
Another way of obtaining gunpowder was to take it by force. The race for gunpowder propelled the other major colonial player toward open rebellion and would soon precipitate the start of the war. This was the reason Gage sent the men to the Provincial Powder House. “No Quantity, however Small, is beneath notice,” wrote George Washington from Cambridge in 1775.19 Even before Washington put out the call, local municipalities had taken it upon themselves to secure as much as they could, resorting to violence when necessary. Four months before Revere would make his famous “midnight ride,” he had journeyed to Portsmouth, New Hampshire, to warn locals that two regiments of British were on their way via sea to collect the gunpowder and munitions held in Fort William and Mary. The fort, situated on Great Island, at the mouth of the harbor, was guarded by a mere handful of British soldiers.
The reaction, which portended trouble for the British, was overwhelming. Led by John Langdon, a staunch revolutionary and later politician, hundreds took to beating drums and chanting on the street of the town, menacing the stronghold across the bay. The province’s chief justice, Theodore Atkinson Sr., confronted the crowd, warning them that “they were going about an Unlawfull Act to take away the Powder out of his Majestys Fort, and that it was the highest Act of Treason and Rebellion They could possibly commit.”
Undaunted by the stark threat, groups of men numbering over four hundred launched boats into the Piscataqua River to obtain the booty. Captain John Cochran, the British commander, refused to hand over the cache and ordered his half-dozen soldiers “not to flinch on pain of death but to defend the fort to the last extremity.”20 At his command, they fired their muskets and three cannons at the patriots who had just landed, all of their shots missing their marks. The Americans immediately swamped the ramparts and took the garrison. “I did all in my power to defend the fort,” an unconvincing Cochran would later tell an inquiry into the event. The Americans had held the British soldiers prisoner for an hour and a half, Cochran later wrote to the governor of New Hampshire, “but all my efforts could not avail against so great a number.”21 So, on December 14, 1774, four months before any shots were fired in Lexington, the colonialists relieved the British garrison of around 10,000 pounds of powder. A plaque would be affixed to the fort, soon renamed Fort Constitution, declaring it the location of the “first victory of the American Revolution.”22 It wasn’t quite Bunker Hill, but similar raids followed across the colonies.
In the end, neither confiscation nor domestic production would be enough to properly supply Washington’s army. American gunpowder production would never take off due to a confluence of issues: inflation, reliance on imported ingredients, the accidental destruction of the few mills that did exist in North America, and then the purposeful destruction of other mills by the British.23 In the end, around 90 percent of the gunpowder used by the revolutionaries was imported, with most of it finding its way to the Americas through the French colonies of the West Indies. Eager to harm their archenemy, the French became the primary source of ammunition. The French had struggled with many of the same problems the Americans did—namely, finding a source of quality saltpeter. Starting in 1775, Antoine-Laurent Lavoisier, one of the leading chemists of the European “Chemical Revolution” of the day, would become director of France’s Gunpowder Administration and transform the nation not only into a self-sufficient gunpowder producer but an exporter of the much-needed chemical compound. Lavoisier recruited top chemists to develop procedures to help him increase both productivity and purity. Soon the Committee of Secret Correspondence, established by the Second Continental Congress to build relationships with friendly Europeans, was sending ships to France’s Mediterranean ports; they would bring back ten tons of powder per voyage and help save the Revolution.
All that was to come later. Right now, as the British were preemptively attempting to disarm the populace, patriot leaders were more convinced than ever that it was imperative to secure gunpowder and weapons—and to do it quickly. While the so-called Powder Alarm had failed to blow up into open, widespread conflict, it was—inadvertently, perhaps—a dry run of the colonial warning system. The next time American militias were called on to repel British confiscatory measures, they would be better armed, more organized, more rapidly deployed, and much more dangerous.