Necessary considerations in forming an estimate for this service.
The force, situation, and condition of the place to be besieged; whether it be susceptible of more than one attack; whether lines of circumvallation or countervallation will be necessary; whether it be situated upon a height, upon a rocky soil, upon good ground, or in a marsh; whether divided by a river, or in the neighborhood of one; whether the river will admit of forming inundations; its size and depth; whether the place be near a wood, and whether that wood can supply stuff for fascines, gabions, &c.; whether it be situated near any other place where a depot can be formed to supply stores for the siege. Each of these circumstances will make a very considerable difference in proportioning the stores, &c. for a siege. More artillery will be required for a place susceptible of two attacks, than for the place which only admits of one. For this last there must be fewer pieces of ordnance, but more ammunition for each piece. In case of lines being necessary, a great quantity of intrenching tools will be required, and a numerous field train of artillery. In case of being master of any garrison in the neighborhood of the besieged town, from whence supplies can readily be drawn, this must be regarded as a second park: and too great a quantity of stores need not be brought at once before the besieged place. The number of batteries to be opened before the place must determine the number of pieces of ordnance; and on the quantity of ordnance must depend the proportion of every species of stores for the service of the artillery.
There must be a battery to enfilade every face of the work to be besieged, that can in any way annoy the besiegers in their approaches. These batteries, at least that part of them to be allotted for guns, need not be much longer than the breadth of the rampart to be enfiladed, and will not therefore hold more than 5 or 6 heavy guns; which, with two more to enfilade the opposite branch of the covert way, will give the number of guns for each ricochet battery. As the breaching batteries, from their situation, effectually mask the fire of the first or ricochet batteries, the same artillery generally serves for both. Having thus ascertained the number of heavy guns, the rest of the ordnance will bear the following proportion to them:
- Mortars.—From 8 inch to 13 inch, about ⅓.
- Small Mortars.—About ¼.
- Heavy Howitzers.—About ⅛.
The fewer natures of ordnance which compose the demand the better, as a great deal of the confusion may be prevented, which arises from various natures of ammunition and stores being brought together.
The Carriages for the Ordnance are generally as follows:
- For 24 Prs. ⅚ the number of guns.
- For Mortars, ⁸/₉ the number of mortars.
- For Howitzers, ¾ the number of howitzers.
- For Stone Mortars, ⁶/₇ the number of mortars.
Ammunition for the Ordnance.
- 24 Prs.——At 1000 rounds per gun.
- Mortars, howitzers, and stone mortars,
- at 800 rounds per piece of ordnance.
- Durtubie.
The following proportion of artillery and ammunition was demanded by a very able officer, for the intended siege of Lisle, in 1794, which place was thought susceptible of two attacks.