nd directed Ewell to cross the Potomac with
his main body and Longstreet to fall back behind the Shenandoah to
act in conjunction with Hill, who had relieved Ewell at Winchester
on the 17th, against any attempt to strike the rear of his long
column. Like Achilles he felt that he was only vulnerable in his
heel.

Several small skirmishes occurred about this time between detachments
of General Schenck's command, which picketed the north bank of the
Potomac, and bands of rebel partisans. The former were surprised
and captured in two or three instances. In one of these expeditions
a locomotive and twenty-three cars were disabled on the Baltimore
and Ohio Railroad. Imboden, too, who occupied Cumberland on the
17th, in order to favor the general plan of invasion, tore up some
miles of the track west of that town, with a view to prevent any
reinforcements coming from that direction.

It would have been much better for the interests of the Southern
Confederacy if Lee, instead of making a downright invasion, had
been content to remain in the valley and threaten Hooker with two
corps, while he used the third to procure unlimited supplies in
Pennsylvania, and to sever all connection between the East and
West, by breaking up the railroads and cutting the telegraph wires.
Such a result, however, would hardly have been sufficient to meet
the expectations of the Southern people, who were bent upon nothing
else than the entire subjugation of the North and the occupation
of our principal cities.

Pleasonton's operations having cleared the way, Hooker moved forward
promptly on the 18th to occupy the gaps. The Twelfth Corps were
sent to Leesburg, the Fifth to Aldie, and the Second to Thoroughfare
Gap. The other corps formed a second line in reserve. This covered
Washington and gave Hooker an excellent base of operations.

In answer to his demand for reinforcements, Crawford's division of
Pennsylvania Reserves, and Abercrombie's division were sent to him.
As the latter was just going out of service, it was of no use.
Hooker contended that his army constituted the proper defence of
Washington, and that it was not necessary to keep a large force
inactive there, who could be of much more service at the front.
The authorities were timid, however, did not see the force of this
reasoning and therefore refused to place Schenck's and Heintzelman's
commands under his orders.

The enemy made a feeble attempt about this time to occupy H