study of the strategic environments at Harper's Ferry, after extended reconnoissance, convinced Johnston that the route of invasion into the valley from Pennsylvania was across the Potomac at Williamsport to Martinsburg, 20 miles west of Harper's Perry and beyond the control of its garrison; and a careful examination of the position and its immediate surroundings, made on May 25th, with Engineer Whiting, convinced him that the place could not be held, even against equal numbers, by the force then in hand; that it was untenable unless he also had possession of the neighboring heights north of the Potomac and east of the Shenandoah, as artillery on those heights could sweep every part of the position and it could easily be turned by the fords of the rivers.
When Johnston took command at Harper's Ferry, the three Federal armies threatening Virginia, each, directly or indirectly, also menaced his position. He supposed that they would co-operate with Richmond as their objective, and from what he could learn, that Patterson and McClellan would direct their first movements so as to combine at Winchester. He considered it absolutely necessary that the troops in the Shenandoah valley under his command should be always ready, not only to meet the attack of Patterson from the northeast and of McClellan from the northwest, but also to unite quickly with the army of the Potomac at Manassas Junction, whenever threatened by McDowell. For such purposes he regarded his army at Harper's Ferry wrongly placed, since Patterson, coming from Chambersburg and marching through Williamsport and Martinsburg toward Winchester, would pass a day's march to the west of it. The only direct road from Harper's Ferry to Manassas, that down the south bank of the Potomac and across by way of Leesburg, was under the enemy's guns on the north side of the river; and if McClellan should come in by the Northwestern turnpike to Winchester, he would be completely in the rear of Johnston's army. For these reasons it was manifest that Winchester, and not Harper's Ferry, was the point to occupy, and he expressed these views in several letters in May and June to the authorities at Richmond, who in reply dissented from his opinions, and held the maintenance of the existing arrangements necessary for retaining command of the valley and communication with Maryland. Notwith-
