From the 1820 Anarchist's Cookbook
The following is taken from The Art of Making Fireworks, London, 1820. The book also has some background on Guido Fawkes.
The h2g2 Post takes no responsibility for anything you do with this information. We'd like to point out that fireworks are fairly cheap, and in the US, you can buy them at Walmart, so we don't recommend pounding your own saltpetre.