saltpetre

Although there are veins of metal in Maranham, they have never been worked; but some saltpetre-works have been established there.

Thou who didst teach weak men and those who suffer To mix saltpetre and sulphur,Have pity on my long misery!

From Scotland would come all the saltpetre which would furnish the means of war to the fleets and armies of contending potentates.

Two ounces of raw sugar must be mixed with an ounce of common salt and half a spoonful of saltpetre.

Having moved our camp to a position north-westward of the town, we discovered a saltpetre manufactory for the use of the rebels.