Comte de Paris, History of the Civil War in America. Vol. 3.
Henry Coppee , LL.D., Ed.

The movements of the Southern cavalry north of the Potomac had given rise, as we have stated, to the most extravagant rumors, and the Federal authorities had great difficulty in distinguishing truth from fiction. As soon as Lee's battalions had set foot on the soil of Maryland the Southern general experienced in his turn some of those difficulties against which his adversaries had hitherto to struggle. Instead of being wrapped up, thanks to the connivance of an entire population, in an impenetrable veil, through which he could perceive all the movements of his opponents, he found himself surrounded with voluntary spies, who, after counting his regiments and talking with his soldiers, who were constantly asking for something to drink, proceeded, as soon as the latter had departed, to report to the enemy all they had seen and heard. On the other hand, soldiers disgusted with the profession of arms, who in Virginia would not have dared to leave the ranks for fear of being betrayed by the inhabitants, finding now a good opportunity for deserting, carried much valuable information to the enemy; so that Ewell's movement upon Hagerstown, which was executed on the 22d, was known to Hooker on the 23d, and on the 25th the latter was fully informed of the passage of the Potomac by Hill's corps at Shepherdstown.

Two bridges had been thrown over the river by the Union general at Edwards' Ferry, near the mouth of Goose Creek, and in rear of the positions occupied by the Second corps at Leesburg.¹ On learning of the arrival of Ewell at Hagerstown, he at once despatched three army corps to hold the left bank of the Potomac and to cover Washington. These were the First, the Third, and the Eleventh, which happened to be nearest the bridges, and which Hooker had placed temporarily under Reynolds' command. On the 25th they stationed themselves around Poolesville, a village in Maryland situated not far from the river, at the intersection of several roads, and at an equal distance from Washington, Harper's Ferry, and Frederick.

That same day, on receipt of fresh intelligence, the commander-in-chief determined to follow the Confederates into Maryland with the remainder of his army. Reynolds led his three army