10. Promptitude, rapidity of execution, and cordial co-operation are essential to success, and the commanding general is confident that this indication of his expectations will insure the hearty efforts of the commanders and troops.

11. Headquarters during the operation will be at the headquarters of the Ninth Corps.

By command of Major-General Meade:

S. WILLIAMS,

Assistant Adjutant-General.

CIRCULAR.] ARTILLERY HDQRS., ARMY OF THE POTOMAC,

Before Petersburg, July 29, 1864.

1. The batteries are not to open to-morrow morning until the signal is given. This signal will be the explosion of the mine under the battery in front of the advanced position of Burnside's corps.

2. Immediately on this mine being sprung the batteries will all open. The greatest possible pains will be taken to avoid interfering with the storming party, which will advance as soon as the mine is sprung, and over the ruins of the explosion. So soon as an entrance is effected here, strong bodies of troops will move to the right and left behind the enemy's line to clear out his troops, and to the front to gain the crest, and, if possible, enter the town of Petersburg. A careful watch must be kept on these movements so as to avoid the possibility of interfering with the advance.

3. The fire will in preference be turned on those batteries which command the point of assault and the ground over which our troops will move. These batteries will probably be found on the crest near the salient, or on the flank of the salient looking toward the Ninth Corps.

4. The batteries in the small redan, and the work known as Fort Hell, will not fire on the advanced point of the salient, as there is danger of such shot striking our attacking troops. They will be directed against the face of the salient, so that the shot which pass over it may strike the work on the crest above it, and after time has elapsed sufficient for an assaulting party to pass well over the crest the guns will be directed still more to the left so as not to strike the town.

5. Commanders on the lines will watch the fire closely, and take all possible precautions against injuring our own troops, whilst bringing their guns to bear on the batteries of the enemy. They will also watch for the movements of the enemy's troops toward our attacking columns, and use every effort to drive them back or retard their movements.

6. The artillery on the line of the Eighteenth Corps will open at the same time as that of the Fifth and Ninth, so as to fully employ the enemy in its front. The fire of the guns and mortars on the left of the line of the Eighteenth Corps will especially be brought to bear on such batteries in front of them as have a fire on Burnside's front.

7. When the enemy's fire has been silenced, the firing on his batteries will cease, and a strict watch be kept on the movements of his troops, and any attempt to reopen the fire of his batteries will be at once met.

HENRY J. HUNT,

Brigadier-General and Chief of Artillery.