DITCH

, in Fortification, called also Foss, and Moat, is a trench dug round the rampart, or wall of a fortified place, between the scarp and counterscarp.

Ditches are either dry, or wet, that is having water in them; both of which have their particular advantages. The earth dug out of the ditch serves to raise the rampart.

The ditch in front should be of such breadth as that tall trees may not reach over it, being from 12 to 24 fathoms wide, and 7 or 8 feet deep. The ditches on the sides are made smaller. But the most general rule is perhaps, that the dimensions of the ditch be such as that the earth dug out may be sufficient to build the rampart of a proper magnitude. The space sometimes left between the rampart and ditch, being about 6 or 8 feet, is called the berm, or list, serving to pass and repass, and to prevent the earth from rolling into the ditch.