and out of the shaft, placing a partition with a door in the main gallery a little out of the shaft, to prevent its exit by the entrance of the mine. The latter plan was more advantageous, because the gases had to travel a less distance in the mine than before.

As the excavation in the mine progressed, the number of men required to carry out the material increased, until at last it took nearly every enlisted man in my regiment, which consisted of nearly 400 effective men. The whole amount of material excavated was 18,000 cubic feet.

The great difficulty to surmount was to ascertain the exact distance from the entrance of the mine to the enemy's works, and the course of these works. This was accomplished by making five separate triangulations, which differed but slightly in their result. These triangulations were made in our most advanced line, and within 133 yards of the enemy's line of sharpshooters.

The size of the crater formed by the explosion was at least 200 feet long, 50 feet wide, and 25 feed deep.

I stood on top of our breast-works and witnessed the effect of the explosion on the enemy. It so completely paralyzed them that the breach was practically 400 or 500 yards in breadth. The rebels in the forts, both on the right and left of the explosion, left their works, and for over an hour not a shot was fired by their artillery. There was no fire from infantry from the front for at least half an hour; none from the left for twenty minutes, and but few shots from the right. The accompanying drawings which I have made, and forward with this report, will explain whatever else has been omitted here.*

I have the honor to be, colonel, very respectfully, your obedient servant,

HENRY PLEASANTS,

Lieutenant-Colonel.

ADDENDA.

GENERAL ORDERS,
HDQRS. ARMY OF THE POTOMAC,

No. 32. August 3, 1864.

The commanding general takes great pleasure in acknowledging the valuable services rendered by Lieutenant Colonel Henry Pleasants, Forty-eighth Regiment Pennsylvania Veteran Volunteers, and the officers and men of his command, in the excavation of the mine which was successfully exploded on the morning of the 30th ultimo under one of the enemy's batteries in front of the Second Division of the Ninth Army Corps.

The skill displayed in the laying out of and construction of the mine reflects great credit upon Lieutenant-Colonel Pleasants, the officer in charge, and the willing endurance by the officers and men of the regiment of the extraordinary labor and fatigue involved in the prosecution of the work to completion is worthy of the highest praise.

By command of Major-General Meade:

S. WILLIAMS,

Assistant Adjutant-General.

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*See pp. 559-563.

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