Magazines : Designs : Galleries

Civil War Field Fortifications

Magazines

Theoretical Designs

Magazine Galleries

A Magazine Gallery may be defined as a passageway underneath and protected by the covering mass that allowed easy access from a trench or the terre-plein of a fortification to a magazine chamber. For the most part galleries were constructed using the same materials as chambers, but in smaller proportions since, being narrower, the burden of the covering mass was not as great and tended to decrease as they neared the entrance and perimeter of the covering mass. Galleries could be positioned to reach and connect to any convenient unengaged point on the either the latitudinal or longitudinal chamber walls. Whether the chamber was raised with its floor at about the natural level of the ground or sunken into a trench the floor and ceiling of the gallery constructed along parallel lines in order to preserve overhead clearance throughout its length. When the chamber was sunken the gallery floor could either be constructed as a gently rising ramp or cut with a sharper angle and shaped into the treads and risers of a stairway. Ramps were relatively easier to maintain and removed the distracting influence steps might have had on troops carrying powder into and out of the magazine. Stairways were necessary when there was insufficient space for a ramp and the gallery had to rise rather steeply from the chamber to the trench or terre-plein.

Neither Mahan's Treatise nor Duane's Manual fully treated the elements of gallery design. Although Mahan mentioned that magazines could be sunken, his example designs and illustrations were based on raised chambers that terminated at the perimeter of the covering mass, in other words, Mahan's chambers had three interior walls and one side that opened full onto the terre-plein of the fortification. The open side was to be covered with a splinter proof shield composed of heavy scantling leaning against the covering mass to produce two triangular shaped entrances. The inclined scantling was to be covered with sandbags or soil to absorb the initial impact of shell fragments or debris striking the shield. Duane's Manual described a specific gallery design for a fully framed gallery that consisted of frames made of six inch square scantling with a horizontal clearance of 2' 6" between stanchions and vertical clearance of 4' 6" between the cap and ground sills. As with the chamber, the gallery was to be given a lining of planks and roofed with heavy timber or fascines and be buried under the covering mass.

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