the land he was awakened by a heavy rumbling noise. His nerves had been
attuned so highly by exciting days that he was awake in an instant and
sprang to his feet, Dalton also springing up with equal promptness.

They saw General Jackson standing in front of his tent and peering down
in the darkness toward the river. Other officers were already gathering
near him. Harry and Dalton stood at attention, where he could see them,
if he wished to send them on any errand. But Jackson was silent and
listening.

The heavy rumbling reports--cannon shots--came again, but they were
fired on their side of the river.

"Gentlemen," said General Jackson, "the enemy has begun the passage.
Those are our guns giving the signal to the army."

Harry's pulses began to throb. But, although fires flared up here and
there, little was to be seen in the darkness. Fortune seemed to have
shifted suddenly to the side of the Union. Not night alone protected
the bridge builders, but a thick, impenetrable fog, rising from the
river and the muddy earth, covered the stream and its shores. The
Southerners could not see just where the bridge head was and their
cannon must fire at random through the heavy darkness. Sixteen hundred
Mississippians were stationed in Fredericksburg below, well concealed
in cellars and rifle pits, but they could not see either, and for the
present their rifles were silent.

But Harry's imagination immediately became intensely vivid again.
He fancied that he could hear through all the shifting gloom the sound
of axes and hammers and saws at work upon that bridge. These army