The sentry and vedette guarding the approach to Washington suggest one
reason why Early did not make his approach to the capital from the
Virginia side of the Potomac. A chain of more than twenty forts protected
the roads to Long Bridge (shown below), and there was no way of marching
troops into the city from the south, excepting over such exposed passages.
Most of the troops left for the defense of the city were on the Virginia
side. Therefore Early wisely picked out the northern outposts as the more
vulnerable. Long Bridge was closely guarded at all times, like Chain
Bridge and the other approaches, and at night the planks of its floor were
removed.
[Illustration: LONG BRIDGE AND THE CAPITOL ACROSS THE BROAD POTOMAC