GENERAL REQUIREMENTS OF SIEGE BATTERIES.
43. 1st. A good platform for and sufficient space to work each gun. The platform must be suited to the gun used. The space required is about 15 feet front by 20 to 25 feet depth.
2d. A parapet which cannot be penetrated by the projectiles which will be fired against it, and which is high enough to afford cover to the gun and its detachment against curved fire. A thickness of 30 feet of earth will usually be enough for the most exposed batteries. A less thickness may be used when the conditions justify it. The height of the interior crest above the terre-plein should not be less than 7½ feet when this is attainable and may sometimes be greater.
3d. Traverses. Each gun is usually separated from the next by a traverse, whose thickness when subject to enfilade fire is the same as that of the parapet (30 feet); under other circumstances the thickness may be reduced if deemed advisable, but should, when practicable, be such that a shell bursting at any point within it will blow out at the top or on one side only.
4th. Bomb and splinter proofs sufficient to cover the gun detachment and reserves against vertical fire. The thickness of cover for these is to be regulated according to the principles laid down in par. 21.
5th. Magazines which will hold at least 24 hours' supply of ammunition, besides recesses near the guns for shells and a few cartridges.
6th. Easy and direct communications for bringing up the guns and placing them in position; including tramways, ramps, etc., etc.
7th. Look-outs or observatories from which the effect of the fire can be seen. These when possible will be placed in high sheltered places well on the flanks of the battery and preferably in advance of it. They may be connected with it by signals, telegraph, or telephone, when necessary.
8th. Screens.—Earthen screens should when possible be thrown up in front of all exposed batteries.