Field ArTillery - US Army Center Of Military History

58 The OrganizaTiOnal hisTOry Of field arTillery
units had been withdrawn or the temporary ones that encircled the capital. Most,
however, were employed in the field, where their lack of training was at least partially
overcome by their enthusiasm and by the assistance of the regular artillery. 27
Except for the few Regular Army companies organized as garrison artillery,
heavy artillery came from volunteer and state organizations. The soldiers were
armed and equipped as infantry and were used to guard the trains and perform other
camp duties either with the active field armies or as garrison troops and guards at
fortified places and depots. A number of heavy regiments were also called to the
front to perform as infantry. 28
As in the Mexican War, artillery batteries were at first distributed to infantry
brigades, and none was retained as a reserve. At the battle of Bull Run in the summer
of 1861, the field artillery batteries served at the brigade level with unsatisfactory
results. Nine incomplete Regular Army batteries, along with a volunteer battery,
manned forty-nine artillery pieces of varying types and calibers. The artillery, however,
was badly managed. Although the Union army commander, Brig. Gen. Irvin
McDowell, had appointed Maj. William F. Barry as his artillery chief, he retained
tactical control over the batteries and only used Barry to pass on any orders to the
artillery. Given the initial unhappy experience with decentralization and the increasing
influence of the Napoleonic model, which called for artillery to be placed with
divisions and corps and the retention of a reserve to throw forward in an offensive
operation, the Union army eventually reorganized the arm. 29
When Maj. Gen. George B. McClellan took over the Army of the Potomac after
Bull Run, he selected Major Barry as his artillery chief and Maj. Henry J. Hunt as
head of the Artillery Reserve and aide-de-camp, earning a promotion to colonel in
the Volunteers. McClellan proceeded to reorganize his force into eleven divi sions,
each comprising three infantry brigades, a cavalry regi ment, and four six-gun batteries.
This divisional structure was generally accepted for other Union armies as
well. Barry immediately established some principles for organizing the artillery.
The proportion of guns to other troops was to be at least 2.5 and preferably 3 to each
1,000 men, and field batteries were to contain six pieces if practicable. No battery
was to have fewer than four guns, and all guns in the same battery were to be of the
same caliber. With a few exceptions, field guns were to be restricted to Ordnance
Department and Parrott rifles and the Napoleons. A reserve artillery of one hundred
cannon was to be organized and a fifty-piece siege train procured.
Each division was to have four field artillery batteries. Of the four divisional
batteries, one was to be formed from the Regular Army and the remainder from the
Volunteers. The captain of the Regular Army battery was to command the divisional
artillery, and he was to direct the instruction of the volunteer batteries in gunnery
27 Naisawald, Grape and Canister, p. 35; George B. McClellan, Letter of the Secretary of War, Transmitting
Report on the Organization of the Army of the Potomac . . . (Washington, D.C.: U.S. Government
Printing Office, 1864), p. 4.
28 See Dyer, Compendium.
29 War Department, War of the Rebellion, 1/2:314–15, 345–48; Naisawald, Grape and Canister, pp.
23–25; McClellan, Letter, p. 13; Birkhimer, Historical Sketch, pp. 78–80.