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 our men, catching them in their hands, returned them.

Our mine had been started some distance back down the hill; consequently when it had extended as far as the parapet it was many feet below it.  This caused the failure of the enemy in his search to find and destroy it.  On the 25th of June at three o’clock, all being ready, the mine was exploded.  A heavy artillery fire all along the line had been ordered to open with the explosion.  The effect was to blow the top of the hill off and make a crater where it stood.  The breach was not sufficient to enable us to pass a column of attack through.  In fact, the enemy having failed to reach our mine had thrown up a line farther back, where most of the men guarding that point were placed.  There were a few men, however, left at the advance line, and others working in the countermine, which was still being pushed to find ours.  All that were there were thrown into the air, some of them coming down on our side, still alive.  I remember one colored man, who had been under ground at work when the explosion took place, who was thrown to our side.  He was not much hurt, but terribly frightened.  Some one asked him how high he had gone up.  “Dun no, massa, but t’ink ’bout t’ree mile,” was his reply.  General Logan commanded at this point and took this colored man to his quarters, where he did service to the end of the siege.