Gunpowder, a granulated composition of salt-petre, sulphur, and charcoal, which readily takes fire, and when secluded from the air, rarefies or expands with great vehemence, by means of its elastic force.

The invention of gunpowder is attributed to Barthold Schwartz, , a German monk ; but there is reason to believe it was not unknown in the time of Alexander the Great; and that Roger Bacon, in 1292, understood the nature of its component parts ; though it was generally introduced into Europe only about the middle of the 14th century.

The method of making gunpowder is nearly as follows : lake four ounces of refined salt-petre, one ounce of brimstone, and six drams of small-coal: reduce these ingredients to a fine powder, and continue beating them for some time in a stone mortar with a wooden pestle, wetting the mixture with a due proportion of water, so as to form the whole into an uniform paste : this will be reduced to grains, by passing it through a tine wire sieve; and, after being carefully dried, it constitutes the common gunpowder.— We do not, however, advise readers in general to make experiments fraught with such imminent danger.

The effects of gunpowder, in mines, etc. may be considerably increased, by leaving some space between the powder and the wadding. Hence, in loading a screw-barrel pistol, care should be taken that the cavity for the powder be entirely filled, so as to leave no space between it and the ball, because musquets, fowling pieces, etc. are very apt to burst, if the wadding be not rammed down close to the powder.

In Birch's History of the Royal Society, weare informed that Prince Rupert manufactured gunpowder of a force exceeding the best kind made at present, in the proportion of 21 to 2 ; and that such superior quality is to be ascribed chiefly to a peculiar method of purifying the nitre, and employing charcoal obtained from the wood of the aler buck-thorn.