A dense body of lancers had sallied from the Mexican right, and sweeping around was forming to charge and turn the American left. The Duncan battery section, with the Voltigeurs running to keep up, was galloping to head the lancers off. And the Sumner dragoons and Rifles were changing front to meet the charge.
The battery was there first—unlimbered in a twinkling—the lancers, a mass of red and yellow, their lances set, tore in for it. Colonel Duncan waited—waited—and when his guns at last burst into canister and grape, with gunners working like mad, the close ranks of the Mexican cavalry melted away in the manner of grain before a giant scythe. The horses reared, fell, or, whirling, bore their gay riders right and left and in retreat.
A new gunfire crashed from the Casa-Mata. At the Second Brigade again? No! The Second Brigade was still streaming rearward in blue rivulets, which swirled, eddied, jetted smoke as the men desperately tried to stand and fight, then slowly flowed on. The new gunfire had issued from a blind trench along which the Sumner column was racing. Down went horse and rider. Major Sumner pointed with his saber, and never wavering, the little column, terribly thinned, dashed on for the lancers, who had re-formed as if to charge again.
Back came the Duncan battery, leaving the lancers to the dragoons and Rifles. Colonel Duncan wheeled his guns into position before the Casa-Mata once more. Quick work this was. He had not been able to do as he wished here, because the Second Brigade infantry had masked his fire, but now, with his field cleared, his three pieces delivered one constant sheet of smoke, out of which the solid shot and canister sped, ripping through the walls and deluging the parapets.
In a moment, as it seemed, the Casa-Mata fire slackened; the doors and windows and roof vomited Mexican soldiers, fleeing helter-skelter, losing hats and knapsacks and muskets; veering to the north out of reach from the mill, they pelted on for the San Cosme gateway of the west city wall.
With a resounding cheer the Second Brigade charged into the defenses. The flag of the Eighth Regiment broke from the roof-top.
Lieutenant Grant closed his glass.
“The battle is over,” he rapped. “Now we can take Chapultepec. If General Scott has the rest of the army in readiness we can take the city itself before night.” Then, as he glanced quickly about: “Aha! A counter-attack!”
Another body of the enemy had appeared—five or six thousand infantry, marching in along the north side of Chapultepec. And the lancers were threatening the Sumner column in the northwest.