From Martinsburg Johnson moved to Shepherdstown, and crossed the Potomac into Maryland, and took position on Catoctin Mountain, where he encountered a force of the enemy with artillery, but Bean soon drove them off, when they retired to Frederick city, closely pursued by Johnson’s cavalry. Here, being reinforced, they made a stand within the confines of the city, and opened fire from their battery, protected by the houses. The fire was not returned for some time, as Johnson was loth to open his guns upon defenceless women and children, but finally forbearance ceasing to be a virtue, he opened his battery, and a sharp artillery fight continued until night, when Johnson retired to the mountain to await Early’s arrival. Early having at length come up, Johnson with his cavalry, and a section of the artillery under command of Lieutenant J. McNulty, proceeded to destroy the railroad bridges at Cockeysville, and this accomplished, he made a rapid move around Baltimore, and struck the Washington branch of the Baltimore and Ohio Railroad at Beltsville, where a large body of the enemy’s cavalry was met, which, after a few shots from the battery and a charge from the cavalry, broke and fled towards Washington in the utmost confusion. The battery, with Johnson’s cavalry, covered Early’s retreat from Washington, though it was but seldom brought into requisition until the army reached Poolsville, where the enemy made a vigorous attack, but were kept in check by Johnson’s cavalry and artillery until the whole army had crossed in safety. On the 29th of July General Johnson was ordered by General Early to accompany McCausland into Pennsylvania and exact a stipulated sum of money from the citizens of Chambersburg, or in case of their not complying with that demand to burn the town. The Baltimore Light Artillery was attached to the brigade, and the whole crossed at McCoy’s Ferry and proceeded on their way. Before day on the morning of the 30th the advance approached Chambersburg, and after feeling the place with a few shells, and finding no enemy, the town was entered and burned.