A military dictionary

by William Duane

[4] For 16 prs. in the French work, we have said 18 prs....for 8 prs. 9 prs....for 12 inch mortars, 13 inch: to which they nearly answer, our measures being generally the same as the English.

Twelve 12 prs. and twelve 4 prs. in reserve.

One 13 inch mortar in each bastion.

Six of 8 inch in the salient angles of the covert way.

Do. in reserve.

Ten stone mortars.

The 12 prs. in reserve, are to be ranged behind the curtain, on which ever side they may be required, and the 4 prs. in the outworks; all to fire en ricochet over the parapet. By this arrangement, the whole of the barbette guns are ready to act in any direction, till the side of attack is determined on; and with the addition of the reserve, 49 pieces may be opened upon the enemy the very first night they begin to work upon the trenches.

The day succeeding the night on which the trenches are opened, and the side to be attacked determined, a new arrangement of the artillery must take place. All the 24 and 18 prs. must be removed to the front attacked, and the other bastions, if required, supplied with 12 prs. The barbettes of the bastions on this front may have each 5 guns, and the twelve 18 prs. may be ranged behind the curtain. The six mortars in reserve must be placed, two in each of the salient angles of the covert way of this front, and with those already there mounted as howitzers,[5] to fire down the prolongations of the capitals. Three 4 pounders in each of the salient places of arms of the ravelins on the attacked fronts, to fire over the palisading, and five 9 prs. in the ravelin of this front. This arrangement will bring 47 guns and 18 mortars to fire on the approaches after the first night; and with a few variations will be the disposition of the artillery for the second period of the siege. As soon as the enemy’s batteries are fairly established, it will be no longer safe to continue the guns en barbette, but embrasures[6] must be opened for them; which embrasures must be occasionally masked, and the guns assume new directions, as the enemy’s fire grows destructive; but may again be taken advantage of, as circumstances offer. As the enemy gets near the third parallel, the artillery must be withdrawn from the covert way to the ravelins, or to the ditch, if dry, or other favorable situations; and, by degrees, as the enemy advances, to the body of the place. During this period of the siege, the embrasures must be prepared in the flanks, in the curtain which joins them, and in the faces of the bastions which flank the ditch of the front ravelins. These embrasures must be all ready to open, and the heavy artillery mounted in them, the moment the enemy attempts a lodgement on the glacis.

[5] The iron mortars, on iron beds, all admit of being fired at low angles.

[6] A German author proposes that the mounds of earth which enable the guns to fire en barbette, should be so arranged, that the embrasures may be opened between them; and when the guns descend to the embrasures, the barbettes will serve as traversers.