FAIRFAX COURT-HOUSE, VA., December 13, 1862.

Major-General HALLECK,

General-in-Chief:

I left the Purnell Legion and Third Delaware at Frederick and the Fifth Maryland at Harper's Ferry. One of my best brigade commanders has but two regiments in his division [brigade?]. I can use three or four regiments in place of those left. In the filling of the brigades, can any be assigned to me?

H. W. SLOCUM,

Major-General, Commanding.

WAR DEPARTMENT,

Washington, December 13, 1862.

Major-General SLOCUM,

Fairfax Court-House, Va.:

A number of unassigned regiments have been sent to Aquia Creek to fill up brigades and divisions. General Burnside will direct the assignment.

H. W. HALLECK,

General-in-Chief.

[DECEMBER 13, 1862.-For Halleck to Dix, and reply, in reference to demonstration on Richmond, see Series I, Vol. XVIII, p.479.]

CUMBERLAND, MD., December 13, 1862-2.15 p.m.

Major-General HALLECK,

General-in-Chief;

All quiet at North Mountain and Martinsburg. Road repairs progressing rapidly-laying about three-quarters of a mile of rail a day. They will reach Martinsburg by the 17th instant. In pursuance of your orders, I sent yesterday a regiment of infantry and battery to strengthen our forces protecting workmen at those points, and to repel any probable advance of enemy. I also ordered Colonel McReynolds, commanding cavalry brigade on line of road east of Cumberland, to proceed to North Mountain, and also to occupy Martinsburg. Colonel McReynolds informs me that one of the two regiments composing his brigade had been ordered yesterday to Hagerstown by General Morell. I am inclined to believe rebel force in Winchester not so large as reported. Our forces occupy Romney, in Hampshire County, and Moorefield and Petersburg, in Harty County.

B. F. KELLEY,

Brigadier-General.

CHARLESTON, [W. VA.], December 13, 1862.

Major-General COX:

In my judgment, the only practicable route would be by the river to Parkersburg, and the time required would depend upon the amount of transportation. I question the policy of taking my command just at