Plan of a fortification under siege showing the fortification under attack and the earthworks which permit the besieging army to approach their object From an illustration first published in 1812 From The Cyclopaedia or Universal Dictionary of Arts, Sci. Plan of a fortification under siege showing the fortification under attack and the earthworks which permit the besieging army to approach their object From an illustration first published in 1812 From The Cyclopaedia or Universal Dictionary