The History of Saltpeter - I

In our last post, we looked into the specialized profession of Saltpeter Men. Which brings us to another important topic of study, to which we will devote a few posts: the history of production of saltpeter (spelled "saltpetre", if you spell things British-style), especially in Europe and America.

As we studied a while ago, the first propellant used in firearms was black powder, otherwise called gunpowder. This was what was used from the 13th century to the 19th century. When we studied the chemistry of black powder a while ago, it was mentioned that the three main components of gunpowder are:

1. Saltpeter
2. Charcoal
3. Sulfur (or Sulphur, in British spelling)

Chemically speaking, the three components are really Potassium Nitrate (from the saltpeter), Carbon (from the charcoal) and Sulfur. Early gunpowder makers used different ratios of these three components to produce gunpowder. For instance, the Germans used a ratio of 4 parts of saltpeter, 1 part of charcoal and 1 part of sulfur by weight in the 1500s. The English used the ratio of 6 parts of saltpeter, 2 parts of charcoal and 1 part of sulfur during the battles of Crecy and Agincourt. By the 1750s or so, almost everyone had settled on the ratio of 15 parts of saltpeter, 3 parts of charcoal and 2 parts of sulfur, and this ratio had continued to modern times as well.

Of the three components, charcoal was well known to practically every one in every region of the world, in the 13th century. 

Pieces of charcoal

Charcoal has a long history, from thousands of years ago. Prehistoric drawings made in caves have been chemically analyzed and determined to be made by charcoal sticks. By the Bronze age, people were using charcoal to make fires hot enough to melt copper and later on, iron as well (ordinary wood fires cannot get hot enough to do this, but charcoal fires can). So, by the time of the 13th century, charcoal was known to everyone in the world. In fact, charcoal manufacturing was even a profession and last names like Collier and Coulier from England, Kohler from Germany, Carbone from Italy and Spain, Carbon from France etc., all indicate that a person's ancestors were charcoal manufacturers. Charcoal is made by burning wood in a closed environment, by starting a fire and then cutting off the supply of air, allowing the water and sap to evaporate and other volatile chemicals in the wood to burn off, leaving only the carbonized wood behind. Of course, this means a supply of dry wood is needed to make charcoal, but since large forests were common in many regions, therefore this ingredient was easily available to everyone during the early days of gunpowder manufacturing. It must be noted that wood from certain types of trees makes better quality charcoal than others. The quality of charcoal is an important factor in the quality of the gunpowder, therefore the techniques of making high quality charcoal were very jealously guarded.

The second component, Sulfur, was also well known to everyone in the 13th century. In fact, it was known to ancient Egyptians, Indians, Chinese, Greeks etc. and mentioned in various literature from these countries. It is even mentioned in the Bible as brimstone. It commonly occurs in pure form in various parts of the world, particularly in volcanic regions and areas where hot springs are present.

Sulfur found naturally on the ground from the island of Vulcano in Italy.

Click on the image to enlarge. Public domain image.

In Europe, Sicily was a major exporter of sulfur since ancient times and it was also available near hot springs in most other countries, therefore gunpowder manufacturers could easily find sulfur from various places.

The third component, saltpeter, was the problematic one. It is the largest component of gunpowder and was the hardest to find historically.

Saltpeter was also known since ancient times, but it is not so readily available everywhere in the world. It does occur naturally in some parts of the world, such as India, parts of Spain, Chile etc. and also in some caverns and cellars. It can also be manufactured by artificial means, but the process is very slow.

William Shakespeare alludes to saltpeter in his play, King Henry IV in act I, scene III:

"And that it was a great pity, so it was,
That villainous saltpetre should be digg'd
Out of the bowels of the harmless earth,
Which many a good tall fellow had destroyed
So cowardly; and, but for those vile guns,
He would himself have been a soldier."

Control of saltpeter meant the control of gunpowder, therefore many countries put a lot of thought into ensuring a supply of saltpeter. This is why saltpeter men had special privileges, which we studied in our previous post. Vast fortunes were made by those who dealt in saltpeter. King Hemchandra (or Hemu), from one of the largest kingdoms in northern India in the 16th century, was not from any royal family, but from a family of green-grocers, and he made his fortune by trading in saltpeter, before becoming the King. The East India Company, which was the world's first multinational corporation, and controlled about 50% of the world trade at one point (beat that, Walmart!), made huge profits from shipping saltpeter from India back to England. Even though the East India company was known for its business in cotton, silks, indigo, tea (it was the East India Company's tea that was thrown into the Boston harbor at the start of the American revolution), they also traded in saltpeter, so much so that about 15% of cargo volume on their ships was saltpeter and it was one of their largest sources of profit. Since the British controlled so much of the Indian saltpeter trade, the French put their best chemists to work to produce artificial sources of saltpeter.

Guano from certain birds and animals was also another important natural source of potassium nitrate. The Guano Islands Act passed by the US Congress in 1856, allowed Americans to take possession of any guano-covered islands not claimed by anyone else and incorporate them as part of the United States territory, until the guano was exhausted. During the US Civil War, bat guano was used to produce gunpowder. In 1879, Peru and Bolivia combined together to fight Chile for mining rights in the Atacama desert, in a conflict known as the Guano war (also known as the Saltpetre War or the War of the Pacific). The main reason for the conflict was because the region was rich in potassium nitrate (ordinary saltpeter) and sodium nitrate (also called Chile saltpeter). This region rapidly became one of the natural sources of saltpeter until World War I.

Therefore, a study of the history of gunpowder manufacturing is largely a study of the history of the production of potassium nitrate. In the following posts, we will study the history of how it was extracted, both from natural sources and artificial production methods.

What is a Saltpeter Man?

Back in the early days of firearms, the propellant used was black powder. One of the components of black powder is a substance called saltpeter (or saltpetre, in British spelling). Saltpeter is more accurately known as potassium nitrate. Of the three main components of gunpowder, this one was the hardest to obtain in Europe, during the renaissance period. In fact, during the earliest years of gunpowder manufacture in Europe, no one was sure if saltpeter was a mineral that could be mined, or was it something that could be cultivated. The name comes from the Latin words, "Sal Petrae", which means "salt of rock", since it has the appearance of a layer of salt encrusted on rocks. Since saltpeter is white in color and since Europe during the early renaissance, got their saltpeter from Asia, it was often referred to as "Chinese snow".

A sample of saltpeter.

With the rise of gunpowder usage in various European kingdoms, it became necessary for governments to secure their sources of saltpeter. For instance, during the reign of Henry VIII in England, most of the saltpeter used for gunpowder manufacture in England was imported. Many countries realized that these supplies could easily be disrupted and therefore looked to produce it domestically. This gave rise to a specialized profession: saltpeter men.

Saltpeter men were people who were trained to extract saltpeter from nitrated earth (we will study this process in detail in subsequent posts). Since it was such a vital ingredient, saltpeter men were actually given special privileges by governments. For instance, in France, the saltpetermen were issued royal warrants by the king, called droit de fouille (translated as "the right to dig"), which allowed them to dig any soil that they suspected contained nitrates, without compensating the owners. In England, similar laws were enacted as well. In fact, in 1646, a new law was passed in the English parliament that allowed saltpetermen to dig in likely places and if any person refused to allow them to dig on their property, that person could be prosecuted by the courts! They were also allowed to demand carts belonging to other people, to be used to transport the saltpeter, and exempt from any taxes or tolls on any of the roadways in England. In theory, the owners of the land that the saltpetermen were digging, were to be compensated for any damage caused by digging, but often, the compensation amount was not enough to cover the damages caused. Saltpetermen were not a popular sight in many areas and many were either beaten up, or bribed by farmers to stay away from their land.

A man digging saltpeter earth in a barn.

Saltpetermen were allowed to dig practically anywhere, including palaces and churches, with the full protection of the British King and many a landowner dreaded the sight of saltpetermen walking in and tasting his soil. In one incident, saltpetermen walked into the church in Chipping Norton and ripped out the seats and tore up the floor, leaving no place for people to sit or kneel in church.

We will study more about saltpeter production in subsequent posts, but suffice it to say that quite a few countries had laws for barns and cellars to be built without flooring, so as to allow saltpeter to form in there. In America, in 1642, a law in Boston declared that "every plantation within this colony shall erect a house in length 20 or 30 foote, and 20 foote wide within one-half year next coming. &c., to make saltpeter." This law was actually based on a similar law passed by the King of England in 1626, that required citizens around London to do the same thing. Similar laws existed in Germany and Sweden as well. In fact, Swedish barns were not allowed to have paving stones until about 1830 or so and farmers were required to supply a certain amount of nitrated earth every year, as part of their taxes!

In the next series of posts, we will study the production of saltpeter throughout the centuries. I promise it will be a very interesting read.

Pommel Bags

In our last couple of posts, we studied devices that people used to protect key parts of flintlock weapons from being exposed to wet weather, namely tompions and cows knees. Today, we will study another device that had its origins in Europe, but became very popular in the United States.

Pommel Bag from the 1870s. Click on the image to enlarge.

In the early 1800s, as settlers gradually started moving westward in the United States, many frontiersmen mounted on horseback, carried large bore pistols for protection. As the technology for repeating weapons was somewhat primitive, these were mostly single-shot models and therefore, each person would carry two or more pistols.

At that time, black powder was still the propellant used for firearms, but it does not burn properly when wet. Therefore, it was necessary to find some way to keep firearms functional, even in bad weather conditions. Of course, it is possible to carry a pistol within a person's clothing to protect it from bad weather, but the problem is that when the weather is cold or wet, people wear multiple layers of clothing to stay warm, which makes the pistol harder to access.

One way around this was to put the pistol in a container, attached to the saddle on the horse. The pommel bag (such as the example above) had a separate compartment designed to hold a firearm, and the cover flap on top kept the rain and snow away. Pommel bags were typically mounted across the front of the saddle and attached to the saddle pommel (which is why they are called pommel bags). This makes it easy for a person to reach into a pommel bag, even when riding the horse. To access the firearm, the user merely had to lift the cover flap to get to it. The pommel bag often carried some additional gear for the pistol, such as extra cartridges, bullet molds, cleaning supplies etc.

When revolver models such as the Walker Colt revolver and the Colt Dragoon revolver came to the market, they were heavy weapons that were impractical to carry on a person, therefore pommel holsters were usually the preferred way of carrying them. The US military even issued holsters for cavalry in the 1850s, designed to carry these heavy revolvers.

A standard issue US military holster from around 1850. Click on the image to enlarge

The above image shows a pair of pommel holsters issued by the US Army around 1850. These were made to hold a pair of Colt Dragoon revolvers.

What is a Cows Knee?

In our last post, we studied tompions which are devices that were invented to prevent rain, snow, mud etc. from entering through the muzzles of flintlock firearms. However, the muzzle isn't the only part of the flintlock that must be kept dry, because water can enter through another place as well. Specifically, the lock, or more precisely, the pan of the flintlock must be kept dry as well. If too much moisture reaches the black powder, it will not ignite properly, so there must be some way to protect the lock.

Parts of a flintlock. Click on the image to enlarge. Public domain image courtesy of wikipedia.

We will study a device called a Cows Knee, that was invented for this purpose.

A Cows Knee is merely a cover for the lock, traditionally made of leather pieces which are sewn together. The leather used in the old days was usually cattle skin or deer skin, since these were cheap and commonly available. The leather is first processed to remove all the hair and fat, then it is tanned to prevent it from decaying, then it is further processed to soften it and color it if needed. Then, the pieces of leather are cut into shape and stitched together to form the cover.

Traditional cows knees came with leather thong straps attached to the ends, so that they could be secured to firearms and held in position instead of sliding off.

A Cows Knee with a single strap. Click on the image to enlarge

A Cows Knee with two straps. Click on the image to enlarge.

As the reader may note, the reason for the name is because it does resemble the knee of a cow, when it is tied to the firearm.

Some other materials that were traditionally used as alternatives to leather were heavy canvas cloth and wool cloth. Whether made of leather, canvas or wool, the material was oiled or greased both on the inside and outside surfaces, to repel water as well. The substance used was generally some animal grease or beeswax.

Some hunters would only tie the front thong and leave the rear one untouched. The reason for this was if they came across an animal and wished to deploy the firearm quickly, they could simply slide the cover forward or flip it over, thereby exposing the lock.

These days, some cows knees models also come with metal buttons or studs, so that people can press the ends together instead of tying knots with the leather thongs. These also make them easier to remove as well, since users don't have to fumble with knots. Some modern models are also made of plastic materials instead of leather or cloth.

A modern Cows Knee model with a stud fastener instead of thongs. Click on the image to enlarge.

Back in the days of flintlock weapons and black powder, these devices were commonly carried by hunters and soldiers of various armies. For instance, from January 29th, 1759, we have the record of an order given by General Jeffrey Amherst, Commander-in-Chief of British forces in North America during the French & Indian war: "And every Man, is to be well clothed, and be furnished with a good Firelock, Powder Horn, Shot Bag, and Cover for the Lock of his Gun, with three Pound of Ball fit for his Gun, and a good Blanket". The "Cover for the Lock of His Gun" mentioned here is what we call a Cows Knee these days.

Cows Knees are still carried by hunters who use black powder firearms, when they hunt in inclement weather.

What is a Tompion?

Back in the day of flintlock firearms, keeping weapons operating in the rain, snow and mud was an important matter indeed. For instance, soldiers could be told to advance to a specific battlefield position, in the middle of a rainstorm. Or a hunter could have been caught in a snowstorm in the woods and didn't want to unload his weapon, in case he met a dangerous animal. To solve this issue, a device called a tompion (sometimes spelled as tampion) was invented. We will study about this device in today's post.

A tompion is simply a cylinder, usually made of wood, which is pushed into the muzzle end of the barrel, and prevents rain, snow, mud etc. from entering the barrel. When ready to fire, the user simply pulls the tompion off the end of the muzzle and then cocks the firearm. Some tompions are made entirely of wood, some have a brass cap at the end, still others are made of brass, rubber and cloth etc.

The above image is a tompion made of wood, for a Springfield M1842 musket, such as those used by both sides of the Civil War here in America. Note the "69" written on the side, which indicates the caliber of the weapon it was intended to fit into. The head of the tompion is made a bit larger than the body, so that it cannot be pushed in beyond that point.

A .58 caliber tompion from a M1861 rifle. Click on the image to enlarge.

The next tompion we see is for a .58 caliber M1861 rifle used by both sides in the Civil War. Note that in both the tompions we have seen so far, they have deep slots cut into the body and the end of the body is slightly tapered. There is a good reason for this design: the tompion must fit snugly in the barrel. By making the end of the body slightly tapered, it is easier to insert into the muzzle. As it is pushed in, the slots allow the body to bend inwards to fit into the muzzle and provide a tight seal. In addition, moisture in the air could cause the wood to expand. The slots ensure that the tompion can be pulled out of the barrel without too much difficulty, even if the wood has expanded a bit.

The above images show tompions for an Enfield 1853 musket. The first image shows the complete Enfield tompion. Notice that it has a brass head cap and shaft and a body made of cork. The second image shows a tompion with the cork part removed. This type of tompion is adjustable. By turning the head of the tompion in one direction, it pushes down the cork and expands its diameter to make a tighter fit. If the head is turned the other direction, it reduces the diameter of the cork, allowing the tompion to be removed from the barrel.

The Enfield Tompion. Click on the image to enlarge.

The next image is of something called Wilmot's Patent Expansible Tompion, invented by George R. Wilmot of Meriden, Connecticut, in 1863.

Wilmot's Patent Tompion. Click on the image to enlarge.

It is made of brass and has two disks, in between which is an elastic packing material, consisting of a rubber strip surrounded by soft cloth. By turning the top, the disks can be moved closer or further apart, which causes the packing material to expand or contract, thus making it fit properly into the barrel of the firearm.

Using tompions, users could keep their black powder weapons somewhat usable in rain, snow, mud, slush etc. and prevent corrosion as well. They were standard issue to armies in America and Europe.

Not only were tompions used for firearms, they were also used for larger cannons as well. In fact, you may still be able to see them in larger guns, such as the example below:

The USS Iowa. Click on the image to enlarge.

The image is that of the USS Iowa, which is now a floating museum in San Pedro, California. Note the tompions plugging the muzzles of the large guns. Fun fact: Your humble editor's wife is from Iowa, and we visit the museum about once a year or so. It is a very fun place to visit and full of history.

In our next post, we will study another piece of equipment that people carried to keep their firearms working in bad weather conditions.

Effectiveness of Old Firearms - IV

In our last post, we looked at a series of penetration tests done in Graz, Austria, to weapons from the 16th, 17th and 18th centuries, compared to modern weapons. But what about accuracy, the reader asks? Today, we will study the accuracy of those ancient weapons against modern weapons.

As was mentioned in the earlier posts in this series, the firearms were typical mass-produced weapons used by infantrymen in the past. The testers also picked two modern rifles and a modern pistol to test against. For testing the accuracy, the firearms were all mounted on a frame and sighted to a paper target at 100 meters (330 feet) distance for rifles, and 30 meters (100 feet) distance for pistols. The paper target measured 167 x 30 cm. (or 5.5 x 1.0 feet), simulating the frontal area of a standing enemy, with an even larger secondary paper target behind it, to track where the bullets were hitting (even if they hit outside the primary target). The actual number of shots fired per weapon varied, but there were about 18 shots fired from each. The table below presents the results:

Results of accuracy tests. Click on the image to enlarge.

As before, a few notes on the results:

1. The modern weapons are highlighted with yellow background at the bottom of the image.
2. The height and width refer to the dimensions of the smallest rectangle that could be drawn around all the bullet holes. The next column is the area of the this rectangle. The last column is the probability that the primary target was hit at all.
3. In keeping with the spirit of the original tests, results are in metric units. To convert cm. to inches, multiply the numbers by 0.3937. To convert the area from sq. cm to sq. inches, multiply the numbers by 0.155.
4. To eliminate human inaccuracy, all weapons were fired from a frame and triggered electronically, bypassing their normal firing mechanisms.
5. Muskets and rifles were tested on targets at 100 meter (330 feet) distance, whereas pistols were tested on targets at 30 meter (100 feet) distance.
6. The flintlock barrel that was used as a pressure tester, was not fired at targets for these tests, therefore it shows up in the chart with green background and the words "no applicable data".
7. The wheellock musket made in Southern Germany in the first half of the 17th century shot so inaccurately, that the tests for it were cancelled. This is shown in the chart with pink background and the words "Tests cancelled due to excessive scatter".
8. The three best performing ancient weapons are highlighted in gray background.

As can be seen from the above figures, long-barreled weapons performed very poorly in the accuracy tests. Only one musket (The 9th weapon - flintlock musket from Austria, made in the second half of the 18th century) showed any good probability of hitting the target (83%). Not surprisingly, this happened to be a rifled barrel. However, two other rifled weapons (the 1st one and the 6th one) performed really badly. In fact, the 6th weapon (the wheellock musket, South German, from the first half of the 17th century) scattered its shots so badly that the test was cancelled for it. For 4 out of the 13 guns tested, the enclosing rectangle's area was larger than the area of the primary target, and for 2 others, it was nearly the area of the primary target. This means that a total of 6 of the 13 long guns shot so inaccurately at 100 meter distances, that they only hit their targets by pure random luck! This is why battlefield commanders of the 16th-18th centuries ordered their troops to shoot at smaller distances, such as 50-70 meters (160 to 230 feet) or even closer than that, in order to be effective. One of the primary reasons for inaccuracy of the ancient firearms is the shape of the bullet, which is a round ball. At distances of 100 meters, the Magnus effect, which we studied earlier, plays a significant role in the ball deviating away from the target. By contrast, modern bullets are tapered and are more stable when flying in the air.

On the other hand, the two ancient pistols fared much better at 30 meter ranges. While they had much larger enclosing areas than the modern pistol, they did manage to put most of their shots into the human-sized target. In fact, one of the two ancient pistols had a 99% probability of hitting its target. Therefore, at closer distances that pistols were used at, they could be pretty deadly. At closer distances, the deviation caused by the Magnus effect is not large enough to cause the ball to miss its target. This explains the number of injuries and deaths in pistol duels, as well as the effectiveness of pistol cavalry units, such as the German Reiters troops.