land Potomac Home Brigade, Colonel Charles Gilpin; Eleventh Maryland Infantry, Colonel Landstreet; seven companies of the One hundred and forty-ninth and three companies of the One hundred and forty-fourth Ohio National Guard, consolidated temporarily, under Colonel A. L. Brown; Captain Alexander's (Maryland) battery and 100 men of the One hundred and fifty-ninth Ohio National Guards, serving as mounted infantry, and commanded by Captain E. H. Leib, Fifth U. S. Cavalry, and Captain H. S. Allen. In addition, I had the services of Lieutenant-Colonel Clendenin's squadron of cavalry, 250 men, and four companies on the First regiment Maryland Potomac Home Brigade, about 200 strong, under Captain Brown. Of this force, it is proper to add, the Eleventh Maryland and all the Ohio troops were 100-days' men.

In the night of the 6th Colonel Clendenin received my orders to take the pike to Middletown and follow it until he found the enemy, and ascertained the strength and composite of his column. Leaving Frederick City at daybreak next morning (the 7th), with his cavalry, and a section of Alexander's battery he drove in a rebel outpost stationed in the mountain pass, and gained Middletown, where he was stopped by a body of cavalry largely superior to his own, commanded by General Bradley T. Johnson. After a smart skirmish, in which both side used artillery, Clendenin was forced back by movements on his flanks. About 10 o'clock he reported the rebels, 1,000 strong, pushing him slowly to Frederick City, which they would reach in two hours, unless I intended its defense. Though out of my department, it had became my duty to save the town, if possible, and as it was but three miles distant, I thought that could be done without jeopardizing the position at the railroad bridge. By direction, therefore, General Tyler sent Colonel Gilpin with his regiment and another gun to support Clendenin and engage the enemy. The company of mounted infantry also went forward. In this movement the railroad was very useful. Colonel Gilpin reached the town in good time, and deployed his command in skirmish order across the Hagerstown pike, half a mile west of the suburbs. Clendenin fell back and joined him. About 4 p. m. the enemy opened the fight with three pieces of artillery. The lines engaged shortly after. At 6 o'clock Captain Alexander, personally in charge of his pieces, dismounted one of Johnson's guns. A little before dark Gilpin charged and drove the rebels, who, under cover of night, finally withdrew to the mountain. You will find the locality of the action indicated on the map* herewith forwarded.

The force opposed, it is worthy remark, were about equal in number, yet Johnson had the advantage; his men were veterans, while Gilpin's, with the exception of Clendenin's squadron, had not before been under fire, a circumstance much enhancing the credit gained by them.

Relying upon intelligence received the evening the above affair took place that a division of veterans of the Sixth Corps was coming by rail to re-enforcement, about midnight General Tyler was sent to Frederick City with Colonel Brown's command to prepare for what might occur in the morning. About daybreak a portion of the First Brigade of the veterans arrived under Colonel Henry, which was also sent to Frederick. The reports of the enemy continued conflicting as before; some stated that Johnson's cavalry, already whipped by Colonel Gilpin, were all the rebels north of the

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*To appear in the Atlas.

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