At any other season we need not take Fredericksburg, but could fall down to Rappahannock Court-House, or below, cross under fire of the gunboats, and march on a shorter line to Richmond; but at this season there would be the difficulty of the roads, and the enemy could move down behind the Mattapony and the Pamunkey, with a railroad to assist him. It is, therefore, impracticable at this season to take Richmond from this point. Can it be taken from any other point?

During the attack on it last summer, the enemy threw large re-enforcements forward from North Carolina and other points farther south by means of the railroad through Petersburg. Get possession of that point, and you not only interrupt his direct communication with the South, stop his troops and supplies, but stand a good chance of cutting his only remaining other southern channel, and the only southerwestern one, by an expedition 50 miles off, at Burke's Station. The force now at Petersburg and its vicinity cannot be large. Make every preparation for crossing the river just below Fredericksburg. Plant your batteries, and build your bridge or get it ready for building, and persuade the enemy, if possible, that you are determined to make the advance on this line. Give it out that the Government at Washington insists upon your moving on this line. The enemy will readily believe it. Assemble a large amount of transportation, and let the Government publish at once its determination to arrest any editor of a papar who publishes any telegram or letter from any of the armies of the east for the next thirty days and suspend the paper. Push forward the force at Suffolk, increased as much as possible by drafts from Fort Monroe, Norfolk, &c., whilst a large force moves up the James River, landing at some point below City Point, or, if possible, on the Appomattox, under protection of the gunboats. For this force take the whole of Banks' force, and of this, all but a few divisions to be left here to the last, to keep up appearances; if they are attacked, to fall back at once, either on the Potomac or Rappahannock, at some suitable point, where they can be protected by the gunboats placed there for the purpose. If properly managed, the force below Petersburg will be cut off. Once in possession of Petersburg, Richmond will fall. Our army will be almost independent of the bad roads; will have its supplies brought by means of the James River almost directly to its camps. We can invest Fort Darling, carry it by assault, and take Richmond in the rear. Our gunboats and the winter roads would effectually prevent the enemy from advancing on Washington, even if that were not well fortified and defended. If we could read the south side of James River, opposite Richmond, before the enemy could concentrate there, the city must fall. If he got there before us, then the great battle must take place below Richmond, and on the side where it is presumed he has but few fortifications, and between him and his re-enforcements.

JOHN GIBBON.

HEADQUARTERS TWELFTH CORPS,
Harper's Ferry, W. Va., November 30, 1862.

Major General H. W. HALLECK,

General-in-Chief:

The pickets of the enemy in our front have disappeared again. Scouts report that Jackson has left the valley; that he passed through Strasburg last Wednesday, and is moving toward Stauton. Four contrabands came in this morning, and make the same report.

H. W. SLOCUM,

Major-General.