The third day Worth reached San Augustin, General Scott and staff resting at Xochimilco with the divisions of Pillow, Quitman, and Twiggs respectively some five and ten miles in rear; no obstruction of moment occurring either in front or rear, unless we except a demonstration of a large force of lancers on the movement of General Twiggs’s division from Ayotla, a demonstration brought speedily to a close by the opening of Taylor’s battery.
Early the next morning, Wednesday, August 18, Scott joined Worth; developed his general plan of attack, and ordered the engineers immediately to make vigorous reconnoissances of the position and force of the enemy. He remarked, “To-day the enemy may feel us, to-morrow we must feel him.”
Accordingly two reconnoissances were made,—one, of the position of San Antonio, three miles from San Augustin, on the great southern road to Mexico, conducted by Major Smith; the other, of the road to San Angel, turning the position of San Antonio, and bringing us to the next great and adjacent causeway to the west. This latter reconnoissance was conducted by Captain Lee.
The first reconnoissance was supported by the whole of Worth’s division. Captain Mason had charge of one party, I had charge of the other. Whilst the whole party of engineer officers with a portion of the escort were examining the position of San Antonio within twelve hundred yards of its guns, and in the causeway itself, the enemy discharged his battery of two large brass 16-pounders, blowing to pieces the body of the gallant Captain Thornton, commanding the escort, and severely wounding an interpreter. The second reconnoitring party (that of Captain Lee) were brought into pretty close contact with a body of the enemy, whom they completely dispersed without any loss. Thus, the enemy felt us the first day. Pillow and Quitman had now come up to San Augustin (ten miles from Mexico), and Twiggs to Xochimilco, four miles in rear.
It was determined to move the main body on San Angel, Worth remaining in front of San Antonio, and by a vigorous combined movement forcing this position and advancing upon Tacubaya.
Accordingly, on Thursday Pillow and Twiggs were pushed forward over a most difficult road, requiring much labor to make it practicable for field-guns, and in full view of a large force of the enemy, who, divining our intentions from the reconnoissance of Wednesday, had intrenched himself in a strong position, barring our passage. As our troops approached, they were brought gallantly into action. Callender’s howitzer battery was advanced to a very exposed position for the temporary purpose of driving in a picket, was not withdrawn in time, and, exposed to a formidable battery of twelve guns, was entirely cut up, its gallant commander receiving severe wounds in both legs. Magruder’s battery of 12-pounders was in like manner advanced and cut up. These batteries were supported by Smith’s brigade on the left, and the 9th infantry on the right. The 9th infantry I led across an open field, exposed to the enemy’s grape, without the loss of a man. They advanced to a strong position in a ravine, which they maintained till dark.
Riley’s brigade and the greater portion of Pillow’s division were pushed forward against the enemy’s right to cut him off from his reserves, and by a vigorous charge take him in flank and hurl him into the gorges of the mountains.
The whole field of approach was a perfect honeycomb of lava projections, entirely impracticable for horse and difficult for foot. Nothing was known of the ground. All the troops advanced with difficulty. That intrepid veteran, Riley, with his gallant brigade, pushed forward and encountered the enemy’s lancers in large force, repulsing them in successive charges. He organized his brigade to charge the battery, but felt it his duty to await orders and support.
Smith, somewhat late in the day withdrawn from the right, reached a village on the left of the enemy’s position, to which Riley had withdrawn, and was reinforced by the greater portion of Shields’s and a portion of Pierce’s brigade. An attack under the direction of Smith was organized, but could not be executed in consequence of the gathering shadows of the night.
At this moment, all offensive operations on our side having ceased and no impression made on the enemy’s line, their reserves coming up in great force and bringing with them additional guns, cheer on cheer rose from their whole line, whilst on our part there was much gloom and despondency. Our commands were much scattered, our batteries had become disabled, and every one was overcome with the fatigues of the day. During the latter part of the day I was reconnoitring in the advanced position of the 9th infantry, and, not knowing the progress of the day in other parts of the field, returned to the rear for orders. I found General Pillow, who seemed somewhat perplexed with the posture of affairs, and gave me no orders till dark was coming on. I endeavored to find my way back, but could not succeed. I was so entirely exhausted that it was with the greatest difficulty that I could drag one foot after the other. Finally I fell upon a small party of rifles and 9th infantry, led by Lieutenant Foster, of the engineers, who were making good their retreat from a house somewhat higher up on the same stream with the position of the 9th infantry, and from which they had been expelled by a whole regiment of the enemy. On hailing the party, Foster recognized my voice, and I concluded to return with him, but so entirely worn down that I required his support. We made our way with great difficulty, occasionally meeting little parties of soldiers seeking their commands. It had already commenced raining. On passing near the place where I left my horse, I could not find him, and was obliged to pursue my way on foot. At length we reached some dragoons near the foot of a hill, where General Scott had placed himself to observe the field, and there learned that he had left half an hour before for San Augustin, three miles distant. I inquired for my horse, but could not find him. Foster kindly lent me his, and after waiting some half an hour I set out on my return to San Augustin in company with Captain Sibley’s troop of dragoons.