At one o'clock the column of the Sixth corps moved away from Fort Stevens, marching through the little village of Tanleytown, following in pursuit of the rebels. We moved rapidly till ten o'clock, then halted, much fatigued, at Potomac Cross Roads. At five o'clock, next morning, we were once more on our way, and after a march of twelve hours through a pleasant country, we made our bivouac at Poolsville, having marched thirty-six miles since leaving Fort Stevens. Our Sixth corps, with the two divisions of the Nineteenth corps, now constituted a new army, under command of General Wright, General Getty having command of the Sixth corps. At Poolsville we lay all day, waiting for our small cavalry force to find out the course which Early's army had taken, but on Saturday morning, the 16th, we were moving at daylight. We marched toward the Potomac, which we forded near the scene of Ball's Bluff slaughter. The spectacle at the ford was novel and exciting. The stream was wide, but not more than two or three feet deep. The bottom was rough and stony, and the current was strong. For nearly a mile up and down the river the brigades were crossing; the stream filled with infantry wading with difficult steps over the uneven bottom, mounted officers carefully guiding their horses lest they should stumble, trains of artillery and wagons slowly toiling through, and groups of pack animals scarcely able to keep their footing under their huge burdens. The laugh of hundreds sounded up and down the river, as some unfortunate footman, slipping from a smooth stone, would, for a moment, disappear beneath the surface of the river, or as some overloaded mule or pack horse, losing his footing, would precipitate his load, and peradventure the small negro boy, who, in order to secure a dry passage across the ford, had perched himself on the top of the bags and bundles, into the rushing waters. The troops gathered upon the southern bank of the river, and the infantry proceeded to empty the water from their boots and shoes, and to wring it from their stockings. This short task over, the march was resumed. Passing through a section where some very interesting conglomerate rocks attracted the attention of those scientifically inclined, we left the little town of Leesburgh behind, and at eight o'clock in the morning encamped in a ploughed field, tired and hungry, and, it must be confessed, a little dissatisfied at the idea of sleeping on ploughed ground while fresh meadows were on every side of us. In this bivouac we spent the Sabbath, and services were held by the chaplains in the various brigades.