Part 22

The mortars are generally at first arranged in battery, adjoining the first gun batteries, or upon the prolongation of the capitals of the works; in which place they are certainly least exposed. Upon the establishment of the half parallels, batteries of howitzers may be formed in their extremities, to enfilade the branches of the covert way; and upon the formation of the third parallel, batteries of howitzers and stone mortars may be formed to enfilade the flanks of the bastions, and annoy the besieged in the covert way. In the lodgement on the glacis, stone and other mortars may also be placed, to drive the besieged from their defences. A great object in the establishment of all these batteries, is to make such an arrangement of them, that they mask the fire of each other as little as possible; and particularly of the first, or ricochet batteries. This may very well be prevented till the establishment on the crest of the glacis, when it becomes in some degree unavoidable: however, even the operations on the glacis may be so arranged, that the ricochet batteries be not masked till the breaching batteries be in a great state of forwardness: a very secure method, and which prevents the soldiers in trenches being alarmed by the shot passing over their heads, is to raise a parados, or parapet, in the rear of the trenches, at such parts where the fire from the besieger’s batteries crosses them. For further details on this subject, and for the manner of constructing batteries, see the word Battery; also the words Ricochet, Breach, Magazine, Platform, &c.

3d. ARTILLERY and Ammunition for the defence of a Fortified Place.

It is usual in an Estimate of Artillery and Ammunition for the Defence of Fortified Places, to divide them into Eight Classes, as follows:

+-----------------------+-----+-----+----+----+----+----+----+----+ | CLASSES. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | +-----------------------+-----+-----+----+----+----+----+----+----+ |Garrisons |12000|10000|8000|5000|3500|2500|1600| 400| |Cannon | 100| 90| 80| 70| 60| 50| 40| 30| |Triangle Gins | 4| 3| 2| 2| 2| 1| 1| 1| |Sling Carts | 4| 3| 2| 2| 2| 1| 1| 1| |Jacks of Sizes | 4| 3| 2| 2| 2| 1| 1| 1| |Truck carriages | 6| 6| 4| 4| 2| 2| 2| 2| |Ammunition carts, &c. | 12| 12| 12| 6| 6| 6| 2| 2| |Tools for Pioneers | 9000| 6000|5000|4000|3500|3000|1000|1000| |Tools for Miners | 300| 200| 100| 100| 100| 100| 50| 5| |Tools for}¹⁄₃ Axes }| 1200| 900| 600| 500| 450| 300| 150| 150| |Cutting }²⁄₃ Billh’ks}| | | | | | | | | |Forges complete | 6| 4| 2| 2| 2| 2| 1| 1| +-----------------------+-----+-----+----+----+----+----+----+----+

The guns will be of the following calibres: one-third of 18 prs.; one-third of 12 prs.; and one-third of 24, 9, and 4 pounders in equal proportions. If the place does not possess any very extraordinary means of defence, it will be very respectably supplied with 800 rounds of ammunition per gun for the two larger calibers, and 900 for each of the others.

Gun Carriages; one-third more than the number of guns.

Mortars; about one-fourth the number of guns in the three first classes; and one-fifth or one-sixth in the other classes. Of these two-fifths will be 13 or 10 inch mortars, and the rest of a smaller nature.

Howitzers; one-fourth the number of mortars.

Stone Mortars; one-tenth the number of guns.

Shells; 400 for each of the 10 and 13 inch mortars, and 600 for each of the smaller ones.

Beds for mortars; one-third to spare.

Carriages for howitzers; one-third to spare.

Hand Grenades; 4 or 5000 for the two first classes; 2000 in the three following classes; and from 1500 to 600 in the three last classes.

Rampart Grenades; 2000 for the first class; 1000 for the four following classes; and 500 for the sixth class; none for the two last.

Fuzes; one-fourth more than the number of shells.

Bottoms of wood for stone mortars; 400 per mortar.

Sand Bags; 500 for every piece of ordnance in the large places, and one-fourth less in the small ones.

Handspikes; 10 per piece.

Tackle Falls for gins; 1 for every 10 pieces to spare.

Musquets; 1 per soldier, and the same number to spare.

Pistols, pairs; one half the number of musquets.

Flints; 50 per musquet, and 10 per pistol.

Lead or Balls for small arms; 30 pounds per musquet.

Powder for small arms; 5 pounds for every musquet in the garrison, including the spare ones.

The above proportions are taken from Durtubie’s Manuel De l’Artilleur.

The following method of regulating the management of the artillery, and estimating the probable expenditure of ammunition in the defence of a fortified place, is extracted from a valuable work on fortification lately published at Berlin. It is particularly applied to a regular hexagon: the siege is divided into three periods, viz.

1st. From the first investiture to the first opening of the trenches, about 5 days.

2d. From the opening of the trenches to the effecting a lodgement on the glacis, about 18 days.