that fired cast-iron shells filled with gunpowder.
Fire arrows
launched from bows and crossbows
Fire arrows partially propelled
by their own exhaust.
Mortality
If the powder scared away evil spirits
and brought good luck at first,
it also scared away human spirits
and brought death.
An elixer of immortality
also a mortal poison.
State secrets
An advantage that depends on secrecy
is only temporary.
If you use it then everyone knows about it.
Because many people have to know
something about it,
“state secret” is an oxymoron.
Suppose a nation abolished secrecy.
It would not only need to give up concealing
but behave so they have nothing to conceal.
Suppose a nation declared
it would have no secrecy. Suppose
true democracy were possible.
The recipe for gunpowder was a state secret,
and trade in nitrous raw materials was restricted.
The Mongols conquered to obtain it.
Around 1376, the Korean Choe Mu-seon bribed a Chinese merchant to get the formula,
and figured how to extract potassium nitrate from soils.
The recipe for gunpowder was a state secret, and trade in nitrous raw materials was restricted. The Mongols conquered to obtain it. Around 1376, the Korean Choe Mu-seon bribed a Chinese merchant to get the formula, and figured how to extract potassium nitrate from soils.
See also in The book of science:
Readings on wikipedia: