Friday, February 26, 2016

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.

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