Parallels

Are trenches cut in the ground before a fortre , roughly parallel to its defenses, for the purpose of giving cover to the besiegers from the guns of the place. The parallels are usually three, with zigzag trenches leading from one to another. The old rule used to be to dig the first at 600 yards’ distance; but the improvements in artillery have rendered a greater distance nece ary, and at Sebastopol the allies made their first trench 2000 yards from the walls. The third trench is very near to the besieged works, and from it saps and zigzag approaches are directed to the covert way. See Siege .