Gillmore’s report
Siege and ordnance glossary
The vocabulary the report is written in.
Gillmore wrote for officers and did not stop to explain himself. These are the terms a reader has to have to follow the approaches, the batteries and the guns.
- Abatis
- An obstacle of felled trees or branches, sharpened limbs outward, laid in front of a work to break up an assault.
- Barbette
- A gun mounted to fire over the parapet rather than through an embrasure. Better field of fire; far less protection for the crew.
- Bombproof
- A shelter roofed with heavy timber, earth and sand to protect men or magazines from shellfire. Battery Wagner's bombproof is why the bombardment of 18 July did not empty the work.
- Breaching battery
- A battery sited and armed to bring down a wall, firing concentrated at one face or gorge. Before Charleston the accepted range was a few hundred yards; Gillmore breached Fort Sumter from over two miles.
- Coehorn mortar
- A small portable mortar for high-angle fire, light enough to be carried forward into a parallel by its crew.
- Embrasure
- The opening cut through a parapet or wall through which a gun fires.
- Enfilade
- Fire delivered along the length of a trench, line or work rather than across it — the reason traverses exist.
- Fascine
- A tight bundle of brushwood used to revet a trench face or steady soft ground under a battery platform.
- Gabion
- A bottomless wicker cylinder set upright and filled with earth; the basic building block of field fortification and siege work.
- Gorge
- The rear face of a fortification. Sumter's gorge wall faced Morris Island, which is why it was the point of aim.
- Grillage
- A framework of timbers laid crosswise to spread a heavy load over ground that will not carry it. What made the Marsh Battery possible.
- Marsh battery
- A battery built in tidal marsh on piles, grillage and sandbags, so that a heavy gun can be fired from ground that will not support a man.
- Monitor
- A low-freeboard armored warship with a revolving turret. Charleston Harbor is where their limits against fixed defenses were established.
- Parallel
- A trench dug roughly parallel to the enemy work, protected well enough to hold troops and guns, from which the next approach is pushed. Not simply a ditch — a base of operations.
- Parrott rifle
- A rifled cast-iron cannon by Robert Parker Parrott, identified at a glance by the wrought-iron reinforcing band shrunk onto the breech. Named for the weight of its bolt.
- Requa battery
- The Billinghurst-Requa volley gun: twenty-five .58-caliber barrels fired together by one percussion cap, up to seven volleys a minute. Used at Charleston to sweep the beach approach.
- Revetment
- The facing — gabions, fascines, sandbags, sod — that keeps the side of a trench or parapet from collapsing. In sand, a permanent occupation.
- Sap
- A covered trench pushed forward toward the enemy work, dug from within so that the diggers are never exposed.
- Sap roller
- A large gabion rolled ahead of the sap head to shield the man at the front of the digging.
- Splinter-proof
- Lighter than a bombproof: a covering meant to stop fragments and flying debris rather than a direct hit.
- Torpedo
- The period term for what would now be called a mine — a submerged or buried explosive charge used as an obstruction.
- Traverse
- An interior bank or barrier that stops fire from sweeping the length of a work, and compartmentalizes damage when it lands.
- Vent erosion
- The enlargement of a gun's vent by escaping gas over many rounds. Untreated it wrecks accuracy and eventually the gun — one of the failures Gillmore records in detail.
- Whitworth rifle
- A British breech-loading rifle with a twisted hexagonal bore, celebrated for range and accuracy and awkward to supply with ammunition.