Magazines : Designs : Position and Protection

Civil War Field Fortifications

Magazines

Theoretical Designs

Position and Protection

Constructing a magazine well enough to sustain enemy artillery fire was of fundamental importance to the protection of its contents, but it was also important to gain additional protection by positioning it under cover of other elements of its field fortification. Nineteenth century manuals suggested several ways in which magazines could be protected by combining them with other features in a field work. D. H. Mahan suggested that magazines be placed under traverses, under barbette artillery mountings where the mass of the parapet and artillery platform would serve as a thick covering mass, or, when the soil was sufficiently dry, chambers could be partially sunken so that only the upper portion of the chamber would be above the natural level of the ground. Duane's Manual and Gibbon's Artillerist's Manual, both of which dealt with magazines exclusively as accessories to batteries open at the gorge that would be used as siege works, suggested placing a magazine about 15 yards in rear of a battery's parapet, or at the end of the battery under the epaulment. In his Military Dictionary H. L. Scott provided an extended quote from Sir John Jones' Journal of the Sieges Carried on By the Army Under the Duke of Wellington in Spain that indicated that magazines were best placed on the flanks of batteries and should never be sited directly behind the center of the rear of the parapet where troops passing powder from the magazine to the battery's armament were most exposed to enemy fire and suffered heavy casualties. Jones also pointed out that siting a magazine at a distance from its battery would limit damage to the battery and its armament in case of accidental explosion of the magazine.

Once the site for a magazine was chosen, specific orientation of the gallery entrance and the thickness necessary for the covering mass to provide adequate resistance to artillery fire could be determined. A magazine sited under the epaulment of a battery, for instance, would necessarily have its gallery entrance oriented toward the rear of the battery or in a direction coincident to a prolongation of the epaulment. The thickness of the covering mass which this this case would coincide with the dimensions of the epaulment, could be adjusted according to the weight of fire that the enemy could bring against the battery; the engaged sides, those which were mostly likely to receive the enemy's fire, could be made thicker than the unengaged sides which faced toward the rear and the terre-plein. The same held true when a magazine was positioned under a traverse; the gallery opened onto the terre-plein either facing directly to the rear of the traverse or turned to face the gorge while the chamber was sunken and the traverse formed the covering mass. In this case the covering mass was increased by the thickness of the parapet which protected the chamber from direct fire while other traverses on the flanks might be positioned to protect the magazine's traverse from enfilade fire.

It must be emphasized that protection by other elements of a work was not the only, and sometimes not even the most important, consideration that determined the location of a magazine. Moisture and drainage also had to be considered, as did convenient service of the fortification's armament. A magazine sited under a traverse where the soil retained too much moisture or one that was placed at a low point in the fortification where ground water flowed around and into it would decompose rapidly and cease to perform its very necessary function of preserving its contents in serviceable condition. A magazine placed too far from the armament it supplied would interfere with the service of the guns as they waited for ammunition handlers to reach the magazine and return to the battery with a resupply of powder, cartridge bags, or shells. Every step that a powder handler had to take to move from a magazine to the armament increased his exposure to vertical fire; if powder could not be passed quickly from a magazine to the armament when under enemy fire then chances were that it could not be passed at all and the armament would be silenced.

The next section covering Practical Designs will show how magazines were actually constructed and sited as elements of field fortifications during the Civil War.

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