 They were used during the Franco-Prussian War but were probably not very effective because a flintlock does not work for long when left untended.Another device, the fougasse, was not victim-operated or mass-produced, but it was a precursor of modern fragmentation mines and the claymore mine.If consisted of a cone-shape hole with gunpowder at the bottom, covered either by rocks and scrap iron ("stone fougasse") or mortar shells, similar to large black powder hand grenades ("shell fougasse").