Ever since it was developed in 10th century China, gunpowder has been used for both war and peace. It served as a propellent for firearms, artillery, and rockets on battlefields around the world, which is how we often think of it. However, it has just as often been used for pyrotechnics such as fireworks and as a blasting agent for quarrying, mining, and building roads. As such, gunpowder is one of humanity’s greatest inventions. Yet, for all its importance, the history and development of gunpowder remains poorly understood.
What is Gunpowder?
Gunpowder is a mixture of sulfur, carbon (charcoal), and potassium nitrate (saltpeter) that is also commonly known as “black powder” due to its color. Compared to other chemical explosives, gunpowder is relatively simple to produce. Each of its three ingredients plays an important role in the reaction. Sulfur lowers the ignition temperature required to start the reaction, while charcoal provides carbon and other fuel for the reaction, and saltpeter (potassium nitrate) provides the oxygen for the combustion reaction. Over the centuries, the exact proportion of each ingredient in the mixture has varied, but generally, it is something like the following: 75% Potassium Nitrate (KNO ₃), 15% Charcoal (C), and 10% Sulfur (S).
Since gunpowder has a relatively slow decomposition rate and a low brisance ( the shattering capability of an explosive) it is classified as a low explosive. Unlike a high explosive, which detonates, a low explosive will deflagrate or burn quickly at subsonic speeds. This means that gunpowder is a better propellant than explosive. Gunpowder is not a particularly efficient chemical explosive as combustion converts less than half of the gunpowder’s mass into gas. Most of the mass is converted into particulates, as either smoke or soot. After combustion, the gunpowder is converted into 56% solid products, 43% gaseous products, and 1% water. A simplified chemical equation for the burning of gunpowder would look something like the following: 10KNO ₃ +8C+3S —2K₂CO₃+3K₂SO₄+6CO₂+5N₂.
The Origins of Gunpowder
Though gunpowder is an invention of undeniable importance, its origins and history are poorly understood. In the West, there was a centuries-long debate around gunpowder’s exact point of origin. Thanks to the pioneering work of Joseph Needham in the 1960s and 1970s, we can now say that gunpowder was developed in China at some point during the 10th century CE. There is some evidence that gunpowder was developed earlier, so at some point, this date may be pushed further back. Medieval Europeans had a very limited knowledge of China so they assumed that gunpowder must have been invented in Europe, though occasionally they credited the Islamic World with its invention. Today, some will still credit Europeans with the invention of gunpowder, but this is no more than cultural chauvinism and has no basis in fact.
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The earliest references to gunpowder are found in Taoist texts of the Tang Dynasty. According to these texts, which include the earliest known recipe for gunpowder, Taoist pharmacists or alchemists were the first to create gunpowder. It was a byproduct of their research into the so-called “elixir of life,” which would cure all disease and imbue one with eternal life and youth. In China, gunpowder was often referred to as the “fire drug” in reference to its origin. Over the course of the following centuries, the recipe was further refined. This was, as can be imagined, a dangerous process. The texts make many references to houses burning down and people suffering horrible burns from experiments gone wrong.
Gunpowder in China
By the 11th Century CE texts of the Song Dynasty record the first chemical recipe for gunpowder. Many early gunpowder recipes include ingredients besides sulfur, charcoal, and saltpeter, which were included for a variety of purposes. Some were included for functional reasons; dung for example was believed to create more noxious smoke. Others included because it was believed that they possessed special properties; garlic and honey were often added for this reason. Much of this experimentation also centered around establishing what proportions of sulfur, charcoal, and saltpeter would produce the best results. There is a bit of wiggle room in the recipe.
It was also around the 11th Century that Song engineers worked to develop various gunpowder weapons. In the past it was common for scholars in the West to claim that the Chinese never used gunpowder as a weapon of war, but this assertion is completely untrue. Song engineers used gunpowder to create all manner of incendiary and explosive weaponry, as well as being the first to harness its capabilities as a propellent. They developed gunpowder fueled fire arrows, bombs thrown by hand and trebuchet, fire lances (spears that could launch projectiles), rockets, and most importantly, the first guns and cannons. These were, of course, far more primitive than their modern counterparts and their impact on the battlefield was limited. Tactics had to be developed before these weapons could have a real impact on the battlefield, and they were not yet available in great enough numbers for their power to be felt. So initially, gunpowder technology remained unknown outside of Song China. This changed in the 12th Century CE with the arrival of the Mongols.
Gunpowder Spreads across Eurasia and Africa
Over the course of the 12th and 13th Centuries CE, the Mongols conquered the largest land empire the world has ever known. In doing so they facilitated the spread of gunpowder technology across Eurasia and Africa. Exactly how this occurred is unclear, but there are some theories. The Mongols are known to have made use of Chinese engineers in their Western campaigns, who employed gunpowder weapons in both Europe and the Middle East. In the 13th and 14th Centuries, “Tartar” or Mongol/Chinese captives were sold as slaves in Europe and the Middle East during the Mongol civil wars. Merchants and scholars traveled freely across Eurasia, bringing with them technology and ideas. Or perhaps the transfer of gunpowder technology from China to the rest of Eurasia and Africa occurred across several different vectors.
The greatest debate over the spread of gunpowder technology focuses on how it was brought to Medieval Europe. For centuries, it was thought that gunpowder was developed in Europe first or possibly at the same time and independently of China. Today we know that this is not the case. However, the question remains, how did it arrive in Medieval Europe? Some have favored a theory of direct transfer. That is to say, Medieval Europeans learned of gunpowder directly from the Mongols or Chinese, either through war, trade, diplomacy, or observations and interaction between scholars. While there is some merit to this theory, it is more likely that the Islamic World served as a middleman, facilitating the transfer. Despite centuries of conflict, there were many established avenues of contact between Christian Europe and the Islamic World in the 13th Century CE. Additionally, the regions of Medieval Europe where the earliest possible evidence of gunpowder being used were Spain and Italy. Both were areas with long and extensive contact with the Islamic World, which would have facilitated the transfer of gunpowder technology.
The Manufacturing of Gunpowder
Gunpowder was initially manufactured by grinding all three ingredients together with a mortar and pestle for a period of about 24 hours. This resulted in a very fine powder that was referred to as “serpentine” powder in Medieval Europe. Besides being labor intensive and limiting the amount of powder that could be made at a time, serpentine powder was difficult to store or transport. The powder had a tendency to separate into its ingredients when subjected to vibration, which required remixing. It was also very susceptible to humidity, meaning that it also often required redrying. Thus, in the 14th century, a new process known as “corning” was developed in Europe and China.
Corning involves adding liquids to the grinding process to create a moist paste. This wet mixing prevented the gunpowder’s ingredients from separating. Additionally, it was discovered that if the past was rolled into balls, the gunpowder would absorb less moisture from the air and travel better. However, the soldiers would still have to grind up the balls into powder before battle. This resulted in uneven sized grains, which made the powder burn unpredictably. By about 1800, the damp balls or mill cakes were being pressed in molds to increase their density and remove excess moisture. The powder was then fed through sieves to create uniform sized grains. From the late 19th century onwards the manufacture of gunpowder focused on standardizing the grains for specific purposes. For example, Fg (Fine grade) powder was made for large bore weapons and shotguns, while FFFFg powder was made for small bore weapons, pistols, and as priming powder.
Attitudes Towards Gunpowder
When gunpowder was first discovered, it was a new technology that no one had ever encountered before. As such, it inspired a variety of different reactions from observers all over the world. Many of the most oft repeated reactions are those that regarded it as something demonic or diabolical. In many ways gunpowder fits this mold quite well. Its ingredients, the smoke and noise it makes, and its ability to wreak death and destruction are certainly quite demonic. It was condemned by military leaders, religious authorities, philosophers, writers, and average citizens on every continent. However, it is important not to overemphasize the influence of these negative reactions and it is questionable just how pervasive such views actually were.
Gunpowder and gunpowder technology spread fast and far. Whenever it became available it was quickly adopted by those living in that area. Even those societies which are described as having “given up the gun” never completely abandoned it. The utilitarian aspect of gunpowder was just too great to ignore and if you did not use it, there was always the chance that someone else would use it against you. Moreover, many of the objections to gunpowder should perhaps be interpreted as condemnation of war in general and not any reaction specifically to gunpowder. The Catholic Church for example, never attempted to ban gunpowder but it did name St. Barbara the patron saint of artillerymen. As with most things then, historical attitudes towards gunpowder were complex and wide ranging, and generalizations should be avoided.
With the development of new chemical explosives and propellants over the course of the late 19th Century, the use of gunpowder began to decline. There were several drawbacks to the use of gunpowder which eventually led to its obsolescence. In particular its hydroscopic nature made it susceptible to moisture, which reduced its effectiveness. Nor did it produce a particularly efficient chemical reaction. The left-over products created fouling which reduced the effectiveness of firearms and artillery while also causing corrosion. At the same time, the smoke that was created by burning gunpowder gave away the soldiers’ position on the battlefield exposing them to the enemy. These issues limited the effectiveness of gunpowder as both a weapon of war and as a tool for civilian projects.
In response to these limitations, in the late 19th century chemists developed nitroglycerin, nitrocellulose (gun cotton), and smokeless powders. These materials gradually replaced gunpowder as both an explosive and a propellant. They were more powerful, safer to manufacture and transport, and produced a far more efficient chemical reaction. As a result of these alternatives, the production and usage of gunpowder dropped dramatically. By 1900, gunpowder had been completely replaced for all intents and purposes, except for fireworks and other pyrotechnic displays.
Any list of humanity’s greatest inventions that does not include gunpowder, would be incomplete. Gunpowder changed the way in which we both built and destroyed. While its use as a weapon of war and the way in which it changed warfare is obvious, its impact on construction, mining, and entertainment should not be overlooked. It would be impossible to list all of the secondary affects and changes that it unleashed as well. Yet, we must remember that gunpowder in and of itself was not responsible for all of this change. It merely provided the means through which these changes could occur. Technological determinism is a trap that should be avoided. Much like attitudes towards gunpowder, the full affect of gunpowder is complicated.
For all its importance the history of gunpowder and exactly how it works is poorly understood. In part this is because just as truly scientific processes and tools were being developed, gunpowder became obsolete. As such, there was less incentive to study it in the way that other chemical explosives have been studied. Luckily, that has changed in recent years, and we now know far more about gunpowder than in the past. Unfortunately, the same cannot be said for our understanding of gunpowder’s early history. In many ways, this simple mixture of sulfur, charcoal, and saltpeter remains as mysterious as it was back in the Middle Ages.