easily have swept the whole line had he not been restrained by the
presence of his seniors.

Unfortunately McClellan was in the rear, but Sumner and Heintzelman,
corps commanders, were soon upon the ground, and with prudent but
ill-timed conservatism declined to sanction the proper movement to
reinforce Hancock, for fear that it would bring on a general engagement
before the army could be properly closed up and placed in position to
participate. Smith recognizing, the great advantage certain to arise
from pushing promptly through the opening he had already found,
besought Sumner for permission to go with the rest of his division to
Hancock's assistance, but this was also denied. As other troops arrived
on the field, Smith moved to the right to make place for them, with the
hope that he might be permitted to continue his march unobserved till
he had come up with his advanced brigade, but orders were sent which
arrested him before he had accomplished the object he had in view. All
day long he was held in the leash with certain victory in sight.
McClellan arrived on the field late in the afternoon, but before he
could get a satisfactory understanding of the condition of affairs,
night came on. Consequently nothing decisive was done that day and a
great opportunity was lost. The wily Magruder, seeing that his left had
been turned, and that his position was untenable, abandoned his works
under cover of darkness and fell back towards Richmond. Obviously this
result was due, first, to the fortunate discovery made by General Smith
and his engineer, and to the successful turning movement of Hancock,
based thereon; and, second, to the certainty that if properly
reinforced by the rest of Smith's division, and by other divisions, if
necessary, as it surely would be as soon as the national commander had
come to comprehend the real condition of affairs, the Confederate
forces would be taken in flank and rear and overwhelmed.