On the 1st of April Lieutenant Grant was appointed quartermaster of the Fourth Regiment—a position requiring peculiar abilities in the incumbent. He was selected for this important office because he was a careful, substantial, and energetic person; and he continued to fill it to the entire satisfaction of his superiors until the close of the war.
Early in April the advance was sent forward on the road to Jalapa. Santa Anna, routed at Buena Vista, had gathered together another army of fifteen thousand men, and intrenched himself in a strong position on the heights of Cerro Gordo, effectually commanding the only passage through the mountain gorges to the capital. Six days after the appearance of the advance before this formidable position, Scott, with the main army, arrived. The stronghold was immediately stormed, and after a series of brilliant operations the position was carried. Three thousand prisoners and forty-three bronze guns were captured, besides seven standards and Santa Anna's private baggage.
Signor Jimen, in the official journal of Mexico, defended the generalship of Santa Anna, and innocently attributed the terrible defeat to "inevitable misfortune, the result of the tactics of the invaders." The Mexicans were flanked by the passage of a portion of the American forces through a ravine which had never before been crossed, and which was deemed impassable. The "tactics" were doubtless the sore trial of the Mexicans, and when I think of the material of which our officers were composed, I am hardly supprised at the magnitude of their achievements. Scott believed in councils of war, and had the benefit of the united thought of his brilliant officers.
By this time, Grant, having been engaged in his fifth battle, was almost a veteran; and in this daring warfare was the training process carried on in his mind; in this arena of brilliant strategy was his military education perfected, and his experience enriched by an observation vouchsafed to only a few.
The army, having beaten down the obstacle at Cerro Gordo, continued on its march towards the capital, occupying Jalapa and Castle Perote on its way. At Puebla the little force was so reduced by sickness, death, and the expiration of the term of volunteer enlistments, that the veteran general no longer deemed it prudent to advance. His numbers had dwindled down to five thousand; and he rested here, in the heart of Mexico, with his handful of men, for three months, until reënforcements swelled his army to eleven thousand—an insignificant force for the conquest of the country.
About the middle of August this little army reached the vicinity of the capital. The city of Mexico is situated on Lake Tezcuco, and is approached over impassable marshes and lagoons by long causeways and bridges. The nature of the country was favorable to an effective defence of the place, especially as the Mexicans had at least four times as many troops in service as their invaders. Located outside of these causeways, and guarding the approaches of the city, were the strongholds of Chapultepec and Churubusco, and the heavy batteries of San Antonio and Contreras, all of them mounting about a hundred pieces of artillery. They were surrounded by morasses, by headlong steeps and rocks heaved into fantastic irregularities by volcanic action. The Mexicans confidently relied upon these natural additions to the strength of their works, and regarded their positions as impregnable.
Turning aside from the national road, by which he had marched to Ayolata, and which here presented too many difficulties for the remaining fifteen miles of his journey, Scott made a detour around Lake Chalco, and approached the city from the south. On the 20th of August the battery on the height of Contreras was captured by an impetuous assault, which occupied but seventeen minutes. The garrison of San Antonio evacuated their position, being cut off from the line of defence by the fall of the supporting works.
Four miles nearer to the city of Mexico, and commanding the road, frowned upon the invaders the strong fortification of Churubusco, where the main body of the enemy's army had been concentrated for an obstinate resistance; but on the same day the stronghold was battered down, and the Mexicans were driven to their only remaining fortress of Chapultepec. All day long Scott's gallant army had been fighting three times their own numbers, lodged in what had been deemed impenetrable works; but their arms were victorious at every point.
After a delay of more than two weeks in receiving and declining some absurd terms for an armistice, offensive operations were resumed by General Scott. The plain on which the city of Mexico is situated is studded with volcanic heights, projecting up from the morasses and lava fields. On one of these eminences, two miles from the city, stood the strong castle of Chapultepec, its base one hundred and fifty feet above the average level of the ground. It had a front of nine hundred feet, which bristled with guns, manned by a picked force, commanded by one of the ablest Mexican officers. This huge work stood, like another dragon, to protect the entrance to the principal causeway leading to the city. Behind it was a powder mill, called El Molino del Rey, which was fortified and occupied by troops, and constituted the principal outer defence of the castle. It was necessary that this position should be first captured, and the duty was assigned to General Worth, of whose command the Fourth Infantry formed a part.
The assault was a desperate one, and Worth lost one fourth of his troops in the action, so obstinate was the defence by the Mexicans, who had reached their "last ditch," and fought with corresponding valor. The position was carried, and in the sharp battle Grant won his first recorded laurel. "Captain Brooks and Lieutenant Grant, with a few men of their respective regiments, by a handsome movement to the left, turned the right flank of the enemy, and the barrier was carried. Second Lieutenant Grant behaved with distinguished gallantry on the 13th and 14th." This is the language of the official report of Major Francis Lee, commanding the Fourth Infantry at the time.