HEADQUARTERS ARMY OF THE POTOMAC,
April 29, 1863.

Major-General SEDGWICK:

GENERAL: Yours, inclosing General Wadsworth's suggestion, is received. The general has retired and is asleep. If the enemy are massing troops in front of Brooks, it will suit the general's purposes. The general wants all correct information as to the numbers of troops beyond Fredericksburg. The balloon must keep us posted and be on the alert.

Telegraph us freely early in the morning. Keep a good look at the size and number of camp-fires. It is very important to know whether or not the enemy are being held in your front. The movement news arrives with regard to the progress made to-day by the right wing, plans from to-morrow will issue. The maneuvers now in progress the general hopes will compel the enemy to fight him on his own ground. He has no desire to make the general engagement where you are, in front of Brooks of Wadsworth.

Please consider this confidential. I inclose copy of an order given Professor Lowe to-night.

Please arrange so that you will get the information, and that it will not be delayed in transmission here. If you have a good officer who will go up and can judge, send him early.

I am, very respectfully, your obedient servant,

DANL. BUTTERFIELD,

Major-General, Chief of Staff.

[Inclosure.]

CAMP NEAR FALMOUTH, VA.,

April 29, 1863.

Professor LOWE,

Chief of Balloon Department:

The major-general commanding directs that your balloon, on service near Sedgwick's command, be sent up at a very early hour in the morning, before sunrise, and that you get in communication with the signal telegraph to forward to these headquarters the earliest information with regard to the numbers, strength, and position of the enemy. This is not to interfere with the service of the balloon at Banks' Ford.

Very respectfully, &c.,

S. WILLIAMS,

Assistant Adjutant-General.

CAMP NEAR FALMOUTH, VA.,

April 29, 1863.

Major-General SLOCUM,

Commanding, &c.:

The major-general commanding directs me to inform you that the bridges are all across here. The demonstration here is a very strong one. Fifty or 60 prisoners taken in the enemy's rifle-pits report Jackson's whole force here. The enemy are in position, anticipating our main attack at Franklin's crossing. The general directs that you move as high up as Chancellorsville; establish your right strongly on the Plank road; look out for your left, too. The map indicates that from Chancellorsville to the Rappahannock is a very strong position. You