The railroad is torn up and the rails badly used up. A man was badly hurt by a heavy stick of timber falling upon him at the bridge that is building over Cedar Run. Six orderlies from Colonel Bayard's cavalry, this evening. Colonel Macomb reported for duty, bringing two wagons, Twelve at dinner this evening - General McDowell, General Van Rensselear, Colonel Macomb, Colonel Schriver, Major Brown, Doctor Magruder, Captain Breck, Captain Sanderson, Captain Barstow, Lieutenant Whittemore, Lieutenant Drouillard, and Lieutenant Cutting. Captain Myers reported by letter that he was sick at Willard's and would join as soon as he could.

April 13.-It being Sunday, there was not much done except that which was really necessary. During the morning the general reviewed Colonel Bayard's regiment of cavalry. The Sixth and Seventh Wisconsin came up from Bristoe this morning and encamped on the opposite [side] of the railroad, near Cedar Run. Part of Colonel Davies' Second New York Cavalry arrived in the afternoon and encamped about a quarter of a mile east of these headquarters. A number of contrabands came in and gave some information. They said the railroad was torn up part of the way from the south side of the Rappahannock. The most of the rebels had left Fredericksburg, and many had left from the rebels on the other side of Rappahannock. Colonel Bayard's regiment started for Fredericksburg about 5 p. m. A rebel soldier from the Twenty-fifth Mississippi came in to-day and gave himself up. General McDowell and Lieutenant Cutting went to Washington about 7 p. m. Colonel McCallum came out to-day to superintend the building of the railroad.

April 14.-Lieutenant Wadsworth arrived from Washington during the night. During the morning it had the appearance of rain but passed over. General McDowell telegraphed from Washington to suspend operations on the Orange and Alexandria Railroad and to make the bridge available for wagons to pass over, but to push forward repairs on the Manassas Gap Railroad as fast as possible; also to place all the disposable force of railroad workmen upon that railroad. Colonel Bayard's regiment returned this afternoon, bringing in a prisoner and his horse, of the rebel pickets, which they found stationed fourteen miles from here. The regiment drove in the pickets of the enemy about three miles. The enemy's troops were mostly militia. A squadron of Colonel Davies' regiment was ordered to picket the road leading to Fredericksburg. They went under the command of Colonel Kilpatrick, Colonel Davies being absent. An order from the Adjutant-General, relieving Lieutenant Whittemore from duty here, was received and ordering him to report for duty to the Chief of Ordnance in person. Quite a number of contrabands came in to-day.

April 15.-The weekly report of last Saturday was made out to-day. Lieutenant Whittemore left for Washington this morning. General McDowell telegraphed he would leave for this place about 10 p. m. General Augur's brigade was ordered here from Bristoe by General McD. direct. They arrived here about 8.30 p. m., and camped east of headquarters about a quarter of a mile. General Augur came and reported. Captain Barstow made a temporary office at the station to-day for quartermaster's purpose. The mail from Washington arrived about 8.30 a. m. Sergeant Wood went down with the mail to-day. General McDowell telegraphed to order up General Augur from Bristoe to Catlett's Station (where we are), and to have him and a battery start to-morrow morning with three days' rations (cooked). General Augur's