James Duncan (United States Army officer)

In 1841 an artillery system emerged where the M1841 6-pounder field gun and the M1841 12-pounder howitzer were adopted as light artillery. At the start of the Mexican–American War, the US Army maintained four artillery regiments, each with 10 companies of 50 men each. However, there were only four highly trained light artillery batteries: Duncan's Company A, 2nd Artillery Regiment, Samuel Ringgold's Company C, 3rd Artillery, Braxton Bragg's Company E, 3rd Artillery, and John M. Washington's Company B, 4th Artillery. The first three were assigned to Zachary Taylor's army from the start, while Washington joined Taylor later.[3] The standard mixed light artillery battery included four 6-pounder field guns and two 12-pounder howitzers.[4]

Duncan joined Taylor's army in the military occupation Texas in 1845–46.[2] On July 31 1845, the first echelon of Taylor's army landed at Corpus Christi, Texas.[5] After months in camp, the first elements of the American army set out for Port Isabel, Texas which would serve as the forward base.[6] Duncan's promotion to captain came through on April 16, 1846.[2]

On May 8, 1846, Taylor's army met the Mexican army of Mariano Arista in the Battle of Palo Alto. Duncan's battery was posted on the American left flank while Ringgold's battery was on the right.[7] In the center stood two heavy 18-pounder cannons. Opposing the 2,228 Americans were 3,826 Mexicans with two 8-pounders and at least six 4-pounders. Duncan's and Ringgold's batteries deployed 100 yd (91 m) in front of the American infantry line and about 700 yd (640 m) from the Mexican defenders. Though many rounds overshot their targets, the effect of the American artillery fire was murderous. Meanwhile, the U.S. infantrymen were largely spectators to the artillery duel. Late in the afternoon, the Mexicans launched an infantry and cavalry attack against the American left wing, but it was repulsed by Duncan's battery. Though the battle ended inconclusively, the Americans lost only five killed, 43 wounded, and two missing. Ten more later died of their wounds including Ringgold who was struck in both legs by a 4-pounder shot. Arista reported 102 killed in his official report, but privately admitted losing 252 men killed.[8]

After finding the Mexican army gone the next morning, Taylor held a council of war in which seven of ten officers voted to wait for reinforcements, Taylor brushed their objections aside and ordered the army to advance. According to one account, Duncan was one of the three officers voting to advance. In another account, Taylor encountered Duncan who remarked, "General, we whipped them yesterday and we can whip them again". Unknown to the Americans, the Mexican soldiers were demoralized by their heavy casualties. In the Battle of Resaca de la Palma on May 9, the Americans routed the Mexican army. The Americans sustained losses of 34 killed and 113 wounded, but Mexican casualties were much heavier and included seven artillery pieces.[9] Duncan was breveted major for "gallant conduct" at Palo Alto and breveted lieutenant colonel for "gallant and highly distinguished conduct" at Resaca de la Palma.[2]

Battle of Molino del Rey map shows the three positions (F) assumed by Duncan's battery.

During the Battle of Monterrey on September 21-24, 1846, Duncan's battery was assigned to Thomas Staniford's brigade in William J. Worth's division. Taylor attacked the city from the north, while sending Worth's troops to attack from the west.[10] The batteries of Duncan and William W. Mackall were involved in the capture of the Bishop's Palace on September 22.[11] Duncan was breveted colonel for "gallant and meritorious conduct" at Monterrey.[2] In early January 1847, Taylor was ordered to transfer Worth's and Twiggs's divisions and two batteries, including Duncan's, to the army of Winfield Scott.[12] Duncan fought at the Siege of Veracruz on March 9–29, 1847, at the Battle of Cerro Gordo on April 17–18, and at a skirmish in Amazoque on May 14.[2]

Scott's army was organized into four divisions, with Duncan's battery in Worth's 1st Division.[13] As the American army approached Mexico City from the east, Scott ordered Worth to reconnoiter a road that would lead the Americans to attack from the south. Worth gave the task to Duncan who reported the road, "not easily obstructed or defended". Soon Scott's entire army moved by that route.[14] At the Battle of Churubusco on August 20, 1847, Newman S. Clarke's brigade, George Cadwalader's brigade, and Duncan's battery captured the tête de pont, a strongpoint defended by a superior force. They then helped capture the San Mateo Convent.[15]

After a two-week truce, the Battle of Molino del Rey was fought on September 8, 1847. Underestimating the strength of the Mexican position, Scott assigned the task of capturing the Molino to Worth's reinforced division, a total of 3,500 men. Worth's soldiers were guided into position by Duncan and James Mason, who had reconnoitered the area. Worth deployed John Garland's brigade and Benjamin Huger's battery on the right, facing the Molino. Worth posted Clarke's brigade and Edwin Vose Sumner's 270 dragoons on the left, facing the Casa Mata fortification. Duncan's battery took position in the center and Cadwalader's brigade was in reserve. The initial American assault was repulsed with serious losses, but Garland's troops eventually overran the Molino. Meanwhile, the Mexican defenders of the Casa Mata drove back Clarke's brigade. A force of Mexican cavalry and infantry appeared to the west, but it was driven off by the fire of Duncan's guns and pursued by Sumner's dragoons. The Casa Mata repelled a second assault, but its defenders finally fled after a sustained bombardment by Duncan's battery.[16]

Duncan fought during the Battle of Chapultepec on September 13, 1846, and during the subsequent capture of the Belén and San Cosme gates on September 13–14.[2] During the occupation of the Mexican capital, a quarrel occurred between the American generals. Gideon Pillow, one of the U.S. division commanders, published an article that appeared in the New Orleans Delta and Picayune newspapers under the pseudonym "Leonidas". The letter claimed Pillow was responsible for the American victories while Scott was mostly a bystander. Everyone immediately guessed that Pillow was the author. On October 23, the Pittsburgh Post published a letter claiming that Worth and Duncan saved Scott from a blunder by convincing the commander-in-chief to use the southern approach to Mexico City. Actually, Duncan wrote a letter to a friend and this was the basis for the Pittsburgh letter. Duncan later took credit for the letter. This was followed by a second letter praising Pillow in glowing terms. At first, Scott tolerated Pillow's unruly behavior, but he finally had enough and brought charges of insubordination against Pillow, Worth, and Duncan.[17]