NOTE Numbers 5.
TORPEDOES (ENEMY'S). (See Figs. 12, 13, 14, 15, and 16, pp. 309, 311.)
More than 60 torpedoes were found planted in the ground in front of Fort Wagner, arranged with an apparatus intended to be exploded by the tread of the men forming and assaulting column. They must have been placed subsequent to the 18th of July. This obstacle extended along the whole south front of the work, from the marsh to the beach. The torpedoes were most numerous in the narrow front next the beach, over which the mass of an assaulting column would have to pass. The first ones discovered (August 26) were 200 yards from the salient of the fort.
Three forms were found. The first, of which there were only about 20, consisted of a loaded 24-pounder shell. In its fuse-hole was firmly fixed a wooden plug having a small hole through it. Extending into powder of the shell through this hole was a fuse enlarged at its upper end into a ball containing the explosive composition, which rested on the plug. Over all, enveloping the shell, was a cylindrical box of thin tin, painted black. The bottom of this box rested on the cap. This arrangement thus completed was buried, fuse-hole up, the explosive composition being even with the surface of the ground. A slight pressure, as a footfall, on the bottom of the box, would explode the shell.
The second form was made of 10-gallon kegs, the ends of which were extended by conical additions, giving the whole the form shown in Figs. 12 and 13.
This peculiar shape, being the same possessed by several floating torpedoes which were found, renders it probable that those planted in front of Fort Wagner were originally intended to be used against our shipping.
Figs. 12, 13, 14, 15, and 16, represent the torpedo and its explosive apparatus; a a are cast-iron flanges suited to the curvature of the outside of the keg and carrying the collars b. These flanges are collars, b, are tapped ten threads to the inch, to receive a hollow plug, c, into which is slipped the plunger d, having a projection or swell at its base, e, and confined in the bore of the plug to prevent its falling through. Screwed into the power [lower part of the] plug is the nipple f, surmounted by a circular piece of wood, g. Through the nipple and wood is inserted the paper tube h, containing the explosive material.
Water is excluded from around the plunger by the stuffing-box nut i, and from the junction of the plug c and the collar b by the leather washer k.
The small hole in the plunder is intended for the insertion of a spike or wire to keep its base from contact with the fulminate until set in the ground.
l is a rectangular piece of board, its ends resting on the ground and plunger, to increase the chances of explosion. In place of this board, a cap having three arms of iron (show in Fig. 16) was in a few instances substituted; stepping on one of the arms would have the same effect as on the board.
The wooden torpedoes were easily rendered harmless by pouring