Saps in a siege, are trenches made under cover from the fire of the place, behind a mantlet or stuffed gabion: they are generally ten or twelve feet broad.—This work differs from the trenches, in as much as the latter are made uncovered. The sap has also less breadth; but when it is as wide as the trench, it bears the same name. There are various sorts of saps, viz.
Single sap, is that which is made on one side only, or, which is the same thing, has only one parapet.
Double Sap, has a parapet on each side, and is carried on wherever its two sides are seen from the place.
Flying sap, is that in which the besiegers do not give themselves the trouble of filling the gabions with earth: it is made where the workmen are not much exposed, and in order to accelerate the approaches.
Sap-faggots, are a kind of fascines, but only three feet long, and about six inches in diameter.
Saucissons, are another species of fascines, from 12 to 19 feet long, and from 8 to 10 inches in diameter, and are used in making batteries, and repairing the breaches.
Sortie. See [Sally].
Tail, or rear of the trench, (Queue de la tranche, Fr.) is the first work the besiegers make when they open the trenches.
Tambour, is a kind of traverse, at the upper end of the trench or opening made in the glacis to communicate with the arrows. This work hinders the besiegers from being masters of the arrow, or discovering the inside of the place of arms belonging to the covert-way.
Traverse, in a siege, a kind of retrenchment which is made in the dry ditch, to defend the passage over it.