What was an Army Corps?—How the Army of the Potomac was Organized—Brigade and Division Formations—“All quiet along the Potomac”—“Why don’t the Army move?”—How Corps were Composed—Their Number—Corps Badges—Their Origin—The Kearny Patch—Worn First by Officers, then by the Privates—Hooker’s Scheme of Corps Badges—Its Extension to other Armies—The Badge of each Army Corps Described 250 CHAPTER XIV. SOME INVENTIONS AND DEVICES OF THE WAR. Improvements in Firearms—In War Vessels—Catch-penny Devices for the Soldiers—Combination Knife, Fork, and Spoon—Water Filterers—Armor Vests and Greaves—Havelocks—Revolvers and Dirk Knives—“High-toned” Haversacks—Compact Writing-desks Smoking-caps and the Turkish Fez—Hatter’s Caps _Versus_ Government Caps—The Numbering and Lettering of Knapsacks—Haversacks and Canteens—How these Equipments Changed Hands 269 CHAPTER XV. THE ARMY MULE. Where Raised—Where the Government Obtained Them—What They were Used for—Compared with Horses—Mule Fodder—How a Mule Team was Composed—How it was Driven—How Mules were Obtained from the Corral—The Black Snake and its Uses—An Incident—Mule Ears—His Pastimes—As a Kicker the Original Mugwump—What Josh Billings Knows about Him—His Kicking Range—How He was Shod—The Mule as a Singer—Under the Pack-saddle—The Mule as a Stubborn Fact—His Conduct under Fire—Captured Mules at Sailor’s Creek—What Became of All the Mules?—The Mule Mortal—“Charge of the Mule Brigade” 279 CHAPTER XVI. HOSPITALS AND AMBULANCES. The First General Hospitals—The First Medical Director—Army Regulations Insufficient—Verdancy of Regimental Surgeons—Hospital Tents—The Origin of Field Hospitals in Tents—Their Capacity—No Ambulances before the War—Two-Wheeled and Four-Wheeled Ambulances—Organization of the Ambulance Corps—The Officers and Privates—The Outfit—Field Hospitals—Their Location—The Men in Charge—Captured Hospitals—A Paroled Prisoner—A Personal Reminiscence—Legs and Arms Unnecessarily Amputated—Anecdote of a Heavy Artilleryman—The Escort of the Wounded—The Insignia of the Ambulance Corps—A Personal Experience—Hospital Railway Trains and Steamboats—The Cacolet 298 CHAPTER XVII. SCATTERING SHOTS. THE CLOTHING.