Arming the Army of the Potomac on the March: A Case Study

     In September 1862, Maj. Gen. George B. McClellan not only faced the task of expelling Gen. Robert E. Lee and his Confederate army from Maryland but also of organizing and arming an army with which to do that. The Army of the Potomac was literally being built on its march towards an as yet unknown battle along Antietam Creek.
     Some corps and divisions fared better than others in the previous campaigns. The 1st Corps was in particularly rough shape as it trudged into Maryland. To resurrect it and restore its fighting spirit, McClellan appointed Joseph Hooker to command the corps. Of the troops under his command in September 1862, McClellan confided to his wife that the 1st Corps troops were "the only doubtful ones." They "are in bad condition as to discipline & everything else," he reported. "Hooker will however soon bring them out of the kinks, & will make them fight if anyone can."(1)

James B. Ricketts

     James B. Ricketts' 2nd Division especially needed a hand. In the recent Northern Virginia campaign, one member of the division speculated, "Our division probably done more marching than any other." The situation within the division was so bad that Ricketts' surgeons banded together and approached the commanding general with the ominous assessment that, in their opinion, "the division was physically unfit for duty."(2)
     The expediency of the dire situation forced by Lee's invasion into Maryland in September 1862 forced the Federals' hand. McClellan had to make use of what he could with what he had. The army's artillery arm was not in good shape. "Many had not been refitted since the August campaign; some had lost more or less guns; others were greatly deficient in men and horses, and a number wholly unserviceable from all these causes combined," wrote Brig. Gen. Henry Hunt, the man responsible for sorting out McClellan's artillery.(3) Certainly, one of those batteries Hunt dealt with was that belonging to Capt. James Thompson's Battery C, Pennsylvania Light Artillery.

     During the final Confederate attack on the afternoon of August 30 at Bull Run, Thompson's gunners heroically stood in the face of the onslaught. Ultimately, though, they lost three of their guns and suffered 16 casualties.(4) James Ricketts mentioned the near destruction of Thompson's battery and their neighboring battery under command of Capt. Ezra Matthews in his report, concluding that "their loss in men and horses entirely disabled these batteries."(5)
     When sorting out the mess of determining what units were fit for a campaign into Maryland and which were not, McClellan decided to bring the 1st Corps along with him, despite its sorry state. Perhaps he had that much confidence in Hooker to "bring them out of the kinks." Regardless, while Ricketts' division encamped around Rockville, Maryland early in the campaign, its depleted artillery received an overhaul. Henry Hunt "was compelled to obtain on the roads the names and condition of the batteries and the troops to which they were attached," he later wrote, all with just one staff officer aiding his efforts.(6) He also had the task of taking the batteries best suited for another campaign and rearming and refitting them.
   

Capt. James Thompson (courtesy of thompsonsbatteryc.org)

     This brings us back to Thompson's Battery. It, like others, was literally put together on the march of the Army of the Potomac towards Frederick, Maryland. Its severe losses forced Hunt to essentially dismantle the 2nd Maine Light Artillery (oddly, this battery suffered far less at Second Bull Run than Thompson's battery did), taking the Mainers' four three-inch ordnance rifles and gifting them to Thompson's Pennsylvanians in Rockville.(7) This all took place within ten days of the Battle of Antietam in the midst of the very campaign itself. The fact that portions of the Army of the Potomac even made it to the Antietam battlefield, let along fight, is incredible at this point in the war.
     Thompson's Battery fought in the Cornfield at Antietam, again suffering heavily. Altogether, Confederate bullets and shrapnel found 23 of his battery's horses; 13 of his men were wounded, including two infantrymen of the 105th New York Infantry attached to his command.(8) This time, Thompson's Battery did not have to be refitted after the Maryland Campaign. It had been so once, and lived to fight another day just a few short weeks after near total disaster befell it at Second Bull Run.

Notes
1. George B. McClellan to Mary Ellen McClellan, September 12, 1862, Stephen W. Sears, ed., The Civil War Papers of George B. Mcclellan (New York: Da Capo Press, 1992), 450.

2. James B. Thomas to Morgan J. Thomas, September 12, 1862, Mary Warner Thomas and Richard J. Sauers, eds., The Civil War Letters of First Lieutenant James B. Thomas: Adjutant, 107th Pennsylvania Volunteers (Baltimore, MD: Butternut and Blue, 1995), 89.

3. Report of Brig. Gen. Henry J. Hunt, OR, vol. 19, pt. 1, 205.

4. John Hennessy, Historical Report on the Troop Movements for the Second Battle of Manassas, August 28 through August 30, 1862 (Denver, CO: National Park Service, 1985), 476; "Return of Casualties in the Union forces, commanded by Maj. Gen. John Pope, during the operations August 16-September 2, 1862," OR, vol. 12, pt. 2, 255.

5. Report of Brig. Gen. James B. Ricketts, OR, vol. 12, pt. 2, 385.

6. Hunt's Report, OR, vol. 19, pt. 1, 205-07.

7. Samuel P. Bates, History of Pennsylvania Volunteers, 1861-5 (Harrisburg, PA: B. Singerly, 1871), 5:867.

8. Report of Capt. James Thompson, Personal Files.