In Journal of Analytical Toxicology, Volume 27, Number 7, October 2003 , pp. 485-492(8). The time to reach 500ng/ml (the point when they can't tell if their testing equipment is giving type I/II errors, as best I understand) is ~47h:30m.
The Chinese finally realized that if you explode gunpowder near people they might die so they started using it in war as a kind of explosive. When Chinese alchemists invented gunpowder it was a mistake. The alchemists were trying to find a potion for immortality and instead they wound up making an explosion.So the opposite effect came out of the original Idea.ne big use that gunpowder evolved into that did not really relate to war was mining. You could mine a whole lot faster by blowing holes in the rock than chipping it with an ax. The invention of gunpowder, and the weapons it is used in, forced war to be in different locations.
Like a number of cool things, fireworks originated in China. Chinese alchemists invented gunpowder sometime before the 11th century (possibly centuries earlier, the record isn't clear). The military application of these were huge, and transformed the history of warfare (making possible bombs, rockets, cannons, and ultimately rifles).