Several readers have written in asking about the ratio of ingredients used to make black powder or gunpowder. There are many recipes for black powder or gun powder, all using the same ingredients (charcoal, saltpeter, sulfur), but in different proportions. So, what is the right
proportion? The answer is: it depends on your purpose. The composition of black powder changes depending on how quickly you want the mixture to burn and whether it is being used as a propellant (e.g. for a rocket or gun) or in a pyrotechnic composition (e.g., firework).
The modern use of black powder is typically for making small fireworks, with a 6:1:1 or 6:1.2:0.8 ratio of charcoal:saltpeter:sulfur. More stable alternatives which produce less smoke are used for most 'gun' powders. I've compiled a table of historically significant compositions, from the 8th century up to the present, so you can see how the composition of black powder has changed over time.