t if they are foot officers, and are properly
detailed for mounted duty, the quartermaster of the staff on which they
serve is obligated to furnish them a horse and equipments. Divisions
usually have an _ordnance officer_, whose duty it is to take charge of
the ammunition of the division, keep the quantity ordered, and supply
the troops in time of battle. By law the chief of artillery at corps
headquarters is the chief ordnance officer for the corps, but this
arrangement has been found impracticable. In the Army of the Potomac the
chief of artillery does not remain at corps headquarters, but is
assigned directly to the command of the artillery, where he also has a
staff, including an ordnance officer, who supplies ammunition and other
articles pertaining to his department, exclusively to the artillery.

The _staff_, it must be recollected, is to an army what the masons,
carpenters, ironworkers, and upholsterers are to a building. As the
latter are the agents for executing the designs of the architect, so the
staff are the medium by which the commander of an army effects his
purposes. Without competent staff officers in all the various grades of
organization constituting an army, the most judicious plans of the
ablest commander will entirely fail. If a campaign is to be made, the
commanding general, having formed his general strategical plan, needs
the advice of his chief of staff as to the condition of his troops, and
his assistance in devising the details. His adjutant-general's office
must contain full records of the numbers of the troops--effective and
non-effective--armed and unarmed--sick and well--present and absent,
with all reports and communications relative to the state of the army.
His quartermaster must have been diligent to provide animals, wagons,
clothing, tents, forage, and other supplies in his department; his
commissary and ordnance officer, the same in relation to subsistence and
munitions--all having made their arrangements to establish depots at the
most accessible points on the proposed route of march. His chief of
artillery must have bestowed proper attention to keeping the hundred
batteries of the army in the most effective condition. His chief
engineer must have informed himself of all the routes and the general
topography of the country to be traversed; he must know at what points
rivers can be best crossed, and where positions for battle can be best
obtained; his pontoon trains and intrenching