Centre, the middle point of any work. From the centre of a place are drawn the first lines to lay down the form of a fortification.
Centre of the bastion, is that point where the two adjacent curtains produced intersect each other.
Citadel, is a kind of fort, or small fortification, of 4, 5, or 6 sides; sometimes joined to towns, &c. Citadels are always built on the most advantageous ground. They are fortified towards the city, and towards the country; being divided from the former by an esplanade, or open place: and serving in one case to overawe the inhabitants; and in the other, not only to hinder the approach of an enemy; but to become a retreat to the garrison, should the town be taken.
Coffers. See [Coffers].
Command is when a hill or rising ground overlooks any of the works of a fortification, and is within reach of common shot; such a hill is said to command that work. See [Command].
Complement of the curtain, is that part of the interior side which forms the demi-gorge.
Complement of the line of defence, is a horn-work with a crown-work before it. See [Crown-work].
Cordon, in fortification, is a round projection made of stone, in a semi-circular form, whose diameter is about 1 foot, and goes quite round the wall, and within 4 feet from the upper part.
The cordon being placed on the top of the revetement of the scarp, is a considerable obstacle to the besiegers, when they attempt to storm a place by applying scaling ladders to the scarp.
Covert-way is a space of five or six toises broad, extending round the counterscarp of the ditch, and covered by a parapet from six to seven feet and a half high, having a banquette: the superior part of this parapet forms a gentle slope towards the country, which terminates at the distance of twenty to twenty five toises; this slope is called the glacis.