late as the 30th of June, when the different brigades were called
together, preparatory to crossing the Potomac, very many were sanguine
that Harper's Ferry was to be made the base of operations, and did not
give up that opinion till they found themselves _en route_ for
Williamsport. But the strong strategic position was neglected for more
than a month; and finally, on the very day when Johnston poured his
fresh legions upon the bloody field of Bull Run, and forced the Federals
to fall back, Patterson, with his back to the foe, entered Harper's
Ferry, with his three months' men, whose term of enlistment was
expiring, by the very road by which Johnston had left it in June.

This neglect of Patterson to occupy the strongest point in his field of
operations puts the stamp of imbecility upon him at the commencement of
his campaign. The rebels expected him to occupy that point, as, even so
late as the time of his crossing the Potomac, the force which disputed
his onward march into the valley of Virginia was not so great as that
held at Charleston to dispute his march from Harper's Ferry in case he
entered the valley there. Patterson himself confessed his mistake, by
retiring to the Ferry in July, for the avowed reason that his three
months' men must soon go home, and he must be in such a position as not
to tempt an attack from the rebels while his column was thus weakened
and disorganized, and before he could be reinforced by three years' men.
Why did not this necessity, and the propriety of holding Harper's Ferry
as a base of operations for this reason alone, if for no other, occur to
the cautious general before, as it did to so many of less military
experience than himself? Patterson, at the last day, thus confesses his
error. It was the first great mistake of his campaign. The second was
one of a different nature.

On the 2d day of July, the army crossed the Potomac at Williamsport, by