THE PRESIDENT of the United States is the commander-in-chief of the army.

The army of the United States, on a peace footing, consists of five regiments of artillery, ten regiments of cavalry, twenty-five regiments of infantry, an Adjutant -General's department, an Inspector-General's department, a Quartermaster's department, a Subsistence department, a corps of engineers, a battalion of engineer soldiers, an Ordnance department, the enlisted men of the Ordnance department, a Medical department, with its corps of hospital stewards, a Pay department, a Bureau of Military Justice, a force of Indian scouts, not exceeding 1,000; officers on the army retired list, and the Professors and corps of Cadets, and a military band at the West Point Military academy.

What Constitutes a Regiment. A regiment of artillery consists of twelve bat-teries of artillery (or cannoniers),and each battery has not exceeding 122 private soldiers attached to it. One battery in each regiment is equipped as light or flying artillery, so called from the rapidity with which it can be moved; seats being contrived for the men who work it, with sufficient horses to enable them to proceed at a gallop.

A regiment of cavalry consists of twelve troops of mounted soldiers, each troop containing not more than seventy-eight enlisted privates. Two regiments of the cavalry are made up of enlisted colored privates. Any of the cavalry force may be dismounted and armed and drilled as infantry, at the discretion of the President.

A regiment of infantry consists of ten companies, each company containing from fifty to 100 privates, as the exigencies of the service may require. The enlisted men of two regiments of infantry are colored men.

There can not be in the army, at one time, more than 30,000 enlisted men.

Duty Of Quartermasters

The Quartermaster's department has charge of purchasing and distributing to the army (and marines in land service) all military stores and supplies requisite for their use, which other corps are not directed by law to provide; to furnish means of transportation for the army, its military stores and supplies, and to pay for, and to provide for and pay all incidental expenses of the military service, which other corps are not directed to provide for and pay.

The Subsistence department is in charge of picked subordinate officers, whose duty it is to receive, at each military post or place of deposit and preserve, the subsistence supplies of the army, under regulations prescribed by the Secretary of War, and to purchase and issue to the army such supplies as enter into the composition of the army ration.

Duty Of Military Engineers

The Corps of Engineers regulates and determines, with the approval of the Secretary of War, the number, quality, form, and dimensions of the necessary vehicles, pontoons, tools, implements, arms and other supplies for the use of the battalion of engineer soldiers. This battalion consists of five companies of enlisted privates of the first and second class, each company containing not more than sixty-four privates of each class. This battalion is recruited and organized, with the same limitations, provisions, allowances, and benefits, in every respect like other troops on a peace footing.

The enlisted men are instructed in, and perform the duties of, sappers, miners, and pontooniers; aid in giving practical instruction in those branches at the West Point military academy, and may be detailed to oversee and aid laborers upon fortifications and other works in charge of the engineer corps of the government, and, as fort-keepers, to protect and repair finished fortifications; but engineers cannot assume nor be ordered on any duty beyond the line of their immediate profession, except by a special order of the President, who may also transfer engineers from one corps to another, regard being paid to rank.

Ordnance Department

The Ordnance department has in charge the enlistment, under the direction of the Secretary of War. of master-armorers, master-carriage makers, and master-blacksmiths, who are mustered in as sergeants; subordinate armorers, carriage-makers and blacksmiths are mustered as corporals; artificers, as privates of the first-class, and laborers, as privates of the second-class. The Chief of Ordnance, subject to the approval of the Secretary of War, organizes and details to other military organizations or garrisons such numbers of ordnance enlisted men, furnished with proper tools, carriages and apparatus as may be necessary, and makes regulations for their government; he also furnishes estimates, and, under the direction of the Secretary of War, makes contracts and purchases, for procuring the necessary supplies of ordnance and ordnance stores for the use of the United States army; directs the inspection and proving of the same, and the construction of all cannon and carriages, and ammunition wagons, traveling forges, artificers' wagons, and of every implement and apparatus for ordnance, and the preparation of all kinds of prescribed ammunition and ordnance stores; establishes depots of ordnance and ordnance stores, in such parts of the United States, and in such numbers as may be deemed necessary; executes, or causes to be executed, all orders of the Secretary of War, and (in time of war) the orders of any general or field officer commanding an army or detachment, for the required supply of all ordnance and ordnance stores for active service; and, half-yearly, or oftener, he makes a report to the Secretary of War of all the officers and enlisted men in his department, and of all ordnance and ordnance stores under his control.

The Army Medical Department

The Medical department furnishes surgical or medical aid to members of the army; has supervision of the purchase and distribution of the hospital and medical supplies; unites with the line officers of the army, under the rules and regulations of the Secretary of War, in superintending the cooking done by the enlisted men; attends, under the direction of the Surgeon-General, to the proper preparation of the rations for the enlisted men; provides such quantities of fresh or preserved fruits, milk, butter and eggs, as may be necessary for the proper diet of the sick in hospitals, and trusses for ruptured soldiers or pensioners.