WAR DEPARTMENT, Washington, August 25, 1862.

Major-General HEINTZELMAN,

Alexandria, Va.:

Send forward all artillery, cavalry, and wagons by land as soon as they have the means to make the march.

H. W. HALLECK,

General-in-Chief.

FALMOUTH, VA., August 25, 1862-12.20 a.m.(Received 12.25 a.m.)

Major General H. W. HALLECK:

I will push Porter up the Rappahannock in the morning as far as he can guard the fords until relieved by Sumner. Is this right?

GEO. B. McCLELLAN,

Major-General.

FALMOUTH, VA., August 25, 1862-12.45 a.m.

Major General H. W. HALLECK:

The only additional information I hear from Pope is from a multitude of his stragglers, who say that he abandoned Rappahannock Station and retreated toward Warrenton Station, carrying off the artillery from the lower fords to some unknown point. You have no doubt taken all possible means to ascertain the exact position of Pope, and I hope you will soon be able to give me definite information. All the means possible to gain it on this line have been used. In the main time you may be sure of my hearty co-operation.

GEO. B. McCLELLAN,

Major-General.

WASHINGTON, D. C., August 25, 1862-10.50 a.m.

Major-General McCLELLAN,

Aquia:

As far as can now be ascertained McDowell's corps is near Sulphur Springs, Sigel's near Fayetteville, Banks' near Bealeton and Rappahannock Station, and Reno's at Kelly's Ford. I hear nothing of Porter's corps. The enemy fell back behind the Rappahannock Crossing, near Waterloo Bridge. Our object now is to hold all the fords of that river until your army can get into position. It is possible that Franklin's corps will be obliged to march out.

H. W. HALLECK,

General-in-Chief.

AQUIA, VA., August 25, 1862. (Received 12 m.)

Major General H. W. HALLECK,

General-in-Chief:

I expect Sumner's corps here to-day; will telegraph you the moment it arrives, so that if circumstances make it necessary for you to leave it at Alexandria it may go there.

If Burnside's information yesterday was correct, Reno must have