The rules for felling trees apply to timbers of wooden bridges, the uprights of the piers being the best point to attack.
To Blow Down a Stockade 12" × 12".—Use 3 lbs. of guncotton per running foot. The slabs should be threaded together, so as to be in contact, and hung or laid against the timbers at the required level.
If gunpowder be used, a charge of 80 lbs. should be allowed for the same stockade when the charge is not tamped; when tamped by having a few sand-bags piled on top, the charge may be reduced to 60 lbs. This would probably make a breach about 6 feet wide.
To Demolish a Gate.—Fifty pounds of guncotton hung against the gate by a nail or pickaxe or laid on the ground will suffice.
The charge of gunpowder should be 200 lbs., covered with sand-bags if possible.
Destruction of Iron Bridges.—Place charge on lower girders near an abutment, and at a point where the thickness of the plates is least. If sections are uniform throughout the length of the bridge, place charge at centre of a span between two piers. When the bridge plate is entirely of iron, place charge on top of beams.
Destruction of Railroad Tracks.—To destroy heavy iron rails, a charge of six 2-ounce disks (including primer) should be used.
To Destroy a Tunnel.—The crown of the arch or the side-walls should be attacked. The points selected should be some distance inside the tunnel.
To Destroy Field-and Siege-guns.—Detonate 1½ lbs. of guncotton on the outside near the muzzle. In heavier wrought-iron guns detonate 4 lbs. in the bottom of the bore, tamping with sand.
Heavy cast-iron guns can be burst by firing 1 lb. of guncotton in the same position and tamping with sand.