ion was received that Johnston had
crossed the Big Black River for the purpose of attacking our rear, to
raise the siege and release Pemberton. The correspondence between
Johnston and Pemberton shows that all expectation of holding Vicksburg
had by this time passed from Johnston's mind. I immediately ordered
Sherman to the command of all the forces from Haines' Bluff to the Big
Black River. This amounted now to quite half the troops about Vicksburg.
Besides these, Herron and A. J. Smith's divisions were ordered to hold
themselves in readiness to reinforce Sherman. Haines' Bluff had been
strongly fortified on the land side, and on all commanding points from
there to the Big Black at the railroad crossing batteries had been
constructed. The work of connecting by rifle-pits where this was not
already done, was an easy task for the troops that were to defend them.

We were now looking west, besieging Pemberton, while we were also
looking east to defend ourselves against an expected siege by Johnston.
But as against the garrison of Vicksburg we were as substantially
protected as they were against us. Where we were looking east and north
we were strongly fortified, and on the defensive. Johnston evidently
took in the situation and wisely, I think, abstained from making an
assault on us because it would simply have inflicted loss on both sides
without accomplishing any result. We were strong enough to have taken
the offensive against him; but I did not feel disposed to take any risk
of losing our hold upon Pemberton's army, while I would have rejoiced at
the opportunity of defending ourselves against an attack by Johnston.

From the 23d of May the work of fortifying and pushing forward our
position nearer to the enemy had been steadily progressing. At three
points on the Jackson road, in front of Leggett's brigade, a sap was run
up to the enemy's parapet, and by the 25th of June we had it undermined
and the mine charged. The enemy had countermined, but did not succeed in
reaching our mine. At this particular point the hill on which the rebel
work stands rises abruptly. Our sap ran close up to the outside of the
enemy's parapet. In fact this parapet was also our protection. The
soldiers of the two sides occasionally conversed pleasantly across this
barrier; sometimes they exchanged the hard bread of the Union soldiers
for the tobacco of the Confederates; at other times the enemy threw over
hand-grenades, and often ou