Bull Run Battle-Ground 60 The Fight at Blackburn's Ford 62 The Country around Fort Henry and Fort Donelson 69 Fort Henry 81 Fort Donelson 95 The Attack on McClernand 114 The Second Engagement 123 The Charge of Lauman's Brigade 128 Pittsburg Landing and Vicinity 155 Disposition of Troops at the Beginning of the Battle 173 The Fight at the Ravine 208 A Rebel Torpedo 230 Island No. 10 239 A Mortar 248 The Naval Fight at Memphis 295 MILITARY TERMS. _Abatis._--Trees cut down, their branches made sharp, and used to block a road, or placed in front of fortifications. _Advance._--Any portion of an army which is in front of the rest. _Aides-de-camp._--Officers selected by general officers to assist them in their military duties. _Ambulances._--Carriages for the sick and wounded. _Battery._--A battery consists of one or more pieces of artillery. A full battery of field artillery consists of six cannon. _Battalion._--A battalion consists of two or more companies, but less than a regiment. _Bombardment._--Throwing shot or shells into a fort or earthwork. _Canister._--A tin cylinder filled with cast-iron shot. When the gun is fired, the cylinder bursts and scatters the shot over a wide surface of ground. _Caisson._--An artillery carriage, containing ammunition for immediate use. _Casemate._--A covered chamber in fortifications, protected by earth from shot and shells. _Columbiad._--A cannon, invented by Colonel Bomford, of very large calibre, used for throwing shot or shells. A ten-inch columbiad weighs 15,400 pounds, and is ten and a half feet long. _Column._--A position in which troops may be placed. A column en route is the order in which they march from one part of the country to another. A column of attack is the order in which they go into battle. _Countersign._--A particular word given out by the highest officer in command, intrusted to guards, pickets, and sentinels, and to those who may have occasion to pass them. _Embrasure._--An opening cut in embankments for the muzzles of the cannon. _Enfilade._--To sweep the whole length of the inside of a fortification or a line of troops. _Field-Works._--An embankment of earth excavated from a ditch surrounding a town or a fort.