The Substance of Civilization: Materials and Human History from the Stone Age to the Age of Silicon by Stephen L. Sass

Author:Stephen L. Sass [Sass, Stephen L.]
Language: eng
Format: epub, pdf
Publisher: Arcade Publishing
Published: 2011-09-27T23:00:00+00:00

These ingredients are the basic components of gunpowder, which is a mixture of saltpeter (potassium nitrate), sulfur, and charcoal.

Byzantium resisted the onslaughts first of Islam and then of the Crusaders for as long as it did because of “Greek fire,” a form of flamethrower that pumped out volatile liquids in bursts of flame. Gunpowder probably originated with similar incendiary weapons based on the use of naphtha, which is volatile. As early as 919, during the chaotic transition between the Tang and Sung dynasties, the Chinese also used such pumps, but added a slow gunpowder fuse to ignite the liquid. By the next century they had learned how to put gunpowder and large amounts of saltpeter in casings of bamboo to make “thunderclap bombs,” meant as much to scare as to harm the enemy. Later they used iron, which shattered and killed men and horses. By trial and error the Chinese discovered that the optimum composition for gunpowder was 75 weight-percent saltpeter, the remainder being made up of approximately equal quantities of sulfur and charcoal.

Packing gunpowder into hollow bamboo stems open at one end and then attaching them to spears, soldiers fashioned fire lances, a rudimentary form of flamethrower. Constricting the open end of the bamboo and turning the tube around, they then invented the rocket. First devised toward the end of the twelfth century, at the high point of Sung rule, the early rockets probably terrified rather than killed people. The key advance in all these innovations, though, was the use of cylinders to hold the gunpowder. Continuing their improvements in the twelfth century, the Chinese replaced the bamboo in the fire lance, first with bronze and then with cast-iron tubes. Finally, adding stones to shoot out of the tube, the Chinese invented the forerunner of the cannon.

The first projectiles, small stones loosely packed above the gunpowder, evolved into balls that fit snugly inside the tube. The carbon and sulfur in gunpowder are excellent reducing agents, meaning that they react strongly with oxygen, forming stable molecules while releasing large quantities of energy. Potassium nitrate has three oxygen atoms out of a total of five atoms in the compound, so that it provides plenty of oxygen for combustion. The reaction of sulfur and charcoal with large amounts of potassium nitrate is explosive, generating a tremendous quantity of heat. Upon ignition, solid gunpowder transforms completely to gas at temperatures well above 3000 degrees, with an accompanying volume increase of more than three thousand times. The gas volume increase shot the ball out of the tube at high velocity—and the world had its earliest cannon.

The first cannon appeared in China toward the end of the thirteenth century, and showed up in the West a few decades later. One of the earliest uses of gunpowder in Europe was at the Battle of Crécy in 1346, where the English, outnumbered more than three to one by the French, defeated them allegedly using cannon in combination with the longbow (which actually played the more crucial role).

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