ction of the
defences. The least distance from this third parallel, as it was
called by an easy stretch of the language, to the enemy's parapet
was about twenty yards, the greatest about forty-five.

About two hundred yards farther to the right of the elbow of the
main sap, a zigzag ran out of the ravine on the left flank of
Bainbridge's battery, No. 8, toward the bastion. Upon this approach,
because of its directness, the use of the sap-roller, or some
equivalent for it, could never be given up until the ditch was
gained.

From the extreme left, after the northern slope of Mount Pleasant
had been gained, a main approach was extended from the flank of
Roy's battery of 20-pounder Parrotts, No. 20, almost directly toward
the river, until the trench cut the edge of the bluff, forming
meanwhile a covered way that connected all the batteries looking
north from the left flank. Of these No. 24 was the seventeen-gun
battery, including two 9-inch Dahlgrens removed from the naval
battery of the right wing, and commanded by Ensign Swann. On the
2d of July, Lieutenant-Commander Terry took command of the _Richmond_
and turned over the command of the right naval battery to Ensign
Shepard. These "blue-jacket" batteries, with their trim and alert
gun crews, were always bright spots in the sombre line. From the
river bank the sap ran with five stretches of fifty or sixty yards,
forming four sharp elbows, to the foot and well up the slope of
the steep hill on the opposite side of the ravine, where the
Confederates had constructed the strong work known to both combatants
as the Citadel. From the head of the sap to the nearest point of
the Confederate works the distance was about ninety-five yards.

From the ravine in front of the mortar battery of the left wing,
No. 18, a secondary approach was carried to a parallel facing the
advanced lunette, No. XXVII., and distant from it 375 yards. The
object of this approach was partly to amuse the enemy, partly to
prevent his breaking through the line, now drawn out very thin,
and partly also to serve as a foothold for a column of attack in
case of need.

From the ravine near Slaughter's house a zigzag, constructed by
the men of the 21st Maine, under the immediate direction of Colonel
Johnson, led to the position of battery No. 16, where were posted
the ten guns of Rails and Baines. The distance from this battery
to the defences was four hundred yards.

On the 15th of June, on the