At dark I withdrew my cavalry from the gap, in order to find water and grass for my horses, which were very much jaded. I left a strong picker in the gap, and encamped my command near Snickersville.

On the 18th I was relieved by an infantry force and ordered to proceed to Ashby's Gap, for which place I started at about 1 p. m. I regret to report that while on the march this day the limber chest of one piece of Keeper's battery exploded, killing 1 man instantly and seriously wounding 5 others; also wounding 2 horses. The piece was disabled, but was taken along. This day we encountered some of Mosby's guerrillas. I encamped my command for the night near Upperville, Va., having marched fifteen miles.

On the 19th of July I reached Ashby's Gap, at about 10 a. m., my advance encountering and driving out a small force of the enemy. Pushing on to the ford, I crossed a part of my command, when they were met by a heavy fire from the enemy, who were posted in a wood and behind a stone fence. At the same time the enemy opened with two pieces of artillery. Under this fire I was unable to cross the remainder of my command, the Second Brigade, under Lieutenant-Colonel Middleton, giving way in considerable confusion, and falling back until beyond the range of the rebel artillery. Major Anderson, who had crossed the river with a portion of the Twentieth Pennsylvania Cavalry, being overpowered by superior numbers, was obliged to recross the river some distance below the ford. A force of riflemen from the enemy, posted behind a stone fence, completely commanded the ford and the river-bank with their long-range rifles. Colonel Tibbits, commanding the First Brigade, held his command steady under this fire in admirable order. I caused one regiment of his brigade to be dismounted and deployed along the river-bank as skirmishers. The remainder of this brigade was held in reserve. At the same time I caused Captain Keeper's battery to be placed in position, and shelled the rebels vigorously, compelling them to move their artillery frequently and to change the position of their forces on the field. During the day my skirmishers engaged the enemy vigorously on the river-bank. The rebels did not display a force to exceed 1,000, with two pieces of artillery. About 5 p. m. I again attempted the crossing of the river. The Twenty-first New York Cavalry, of Colonel Tibbits' (First) brigade, was ordered to charge across the ford and attack the enemy's position, and, if possible, to dislodge them. This movement was superintended by one of my staff in person. The regiment, under Lieutenant-Colonel Fitz Simmons, charged gallantly across the ford and up to the very mouths of the enemy's cannon. They were met by a very destructive fire from the rebel riflemen and artillery, and compelled again to recross the river. This charge, though a desperate one, was splendidly executed. One-fifth of the men of the Twenty-first New York Cavalry engaged, and about one-half of the officers, including Lieutenant-Colonel Fitz Simmons, were either killed or wounded in the charge. The enemy now displayed several regiments of infantry, six pieces of artillery, and a regiment of cavalry. He did not, however, attempt to follow across the ford. The available force of my command being only about 2,000, I did not again attempt the passage of the ford. My artillery did excellent execution. The next day I ascertained from citizens who crossed into my lines that the enemy lost 100 in killed and wounded. This night, leaving the ford strongly guarded, I

21 R-VOL XXXVII, PT I.