Gunpowder
Gunpowder is a substance which burns very rapidly and is used as a propellant in firearms. There are two types:
- Black powder—invented by the Chinese in the 9th Century—was the only widely-known and used practical explosive until the 20th Century. However, it is now primarily only used for fireworks, model rocket engines and in reproduction weapons.
- Smokeless powder replaced black powder as a propellant at the end of the 19th Century and is used in all modern guns.
Both forms of gunpowder burn producing a subsonic deflagration wave rather
than the supersonic detonation wave which high explosives would
produce. This reduces peak pressures in a gun, but makes it less
suitable for shattering rock or fortifications. Without a propellant
the gun could not have been born, so we must first look at the story
of gunpowder, the sole propellant in use up to the 19th century.
From ancient times throughout the known world men had used incendiary
mixtures for warlike purposes. They were well-acquainted with saltpetre
(potassium nitrate), the most potent of the three ingredients of
gunpowder, its effect when burned with charcoal and sulphur, the
other two, as well as with other substances. That someone would
eventually chance upon a mixture which exploded when ignited was
inevitable. Gunpowder was invented in China in the 9th century.
The invention appears to have been by accident by alchemists seeking
the elixir of immortality, and the first references to gunpowder
appear as warnings in alchemy texts not to mix certain materials
together. By the 10th century, gunpowder began to be used for military
purposes in China in the form of rockets and explosive bombs fired
from catapults. The first reference to cannon appears in 1126 when
oil bamboo tubes were used to launch missiles at the enemy.
Eventually bamboo tubes were replaced by metal tubes, and the oldest
cannon in China dates from 1290. From China, the military use of
gunpower appears to have spread to Japan and Europe. It was used
by the Mongols against the Hungarians in 1241 and was mentioned
by Roger Bacon in 1248. By the mid 14th century, early cannons are
mentioned extensively both in Europe and in China.
In China as in Europe, the use of gunpowder to produce firearms
and cannon was delayed by difficulties in creating metal tubes that
would contain an explosion. This problem may have led to the false
myth that the Chinese used their invention only for the manufacture
of fireworks. In fact, gunpowder powered cannon and rockets were
extensively used in the Mongol conquests of the 13th century and
were a feature of East Asian warfare afterwards.
The short squat and thick city walls of Beijing for example, were
specifically designed to withstand an artillery attack, and the
Ming dynasty moved the capital from Nanjing to Beijing specifically
because the hills around Nanjing were good locations for invaders
to place artillery.
However, while mixtures involving the crude saltpetre dug from the
ground or scraped from the walls of cellars by the ancients can
be made to burn quite fiercely, they cannot be made to explode.
To make an explosive mixture the saltpetre must first be refined.
For over 500 years military historians attributed both the discovery
of gunpowder and the invention of the gun to one Berthold Schwarz
(Black Berthold), a German monk so-called because he dabbled in
the 'black art' of alchemy. They based their beliefs on an entry
allegedly made under the year 1313 in the records of the city of
Ghent, but a study carried out in 1923 by Sir Charles Oman revealed
the entry was a marginal note, not a contemporary entry, inserted
not in 1313 but in 1393, by which time guns were in general use
throughout Europe. The entry was therefore declared invalid.
Extensive research produced not one scrap of evidence that Schwarz
ever existed. He is now seen as a legendary figure, rather like
Robin Hood - or perhaps Friar Tuck! It is thought the entry, made
in a foreign hand, may have been made by a German scribe anxious
to credit his countrymen with both discovery and invention.
Early makers simply pounded quantities of the three ingredients
into powder and mixed them according to their own particular recipes.
No finite method of proving the product existed; quality was judged
by the loudness of the bang it made! Such a method of 'proof' seems
funny to us today, but it was not quite so funny 500 years ago;
14th century Gunners were well aware of the effect of the sound
of guns on an uninitiated enemy. They frightened not only the horses
but also the ignorant and superstitious soldiery who saw guns as
instruments of the devil - and Gunners as his henchmen!
Known as 'serpentine' (in allusion to an early type of ordnance)
or 'meal' early gunpowder possessed several faults; firstly, jolting
during transport caused the ingredients to separate, the heaviest
ending up on the bottom of the barrel, the lightest at the top.
The ingredients were therefore often carried separately and mixed
on the gun position, creating in the process a highly explosive
dust easily ignited by spark or friction.
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