The following in an extract from Captain Churchman's report of yesterday, the 5th instant, received this morning:

I have scouted this [country] from Libery through Middleburg to Emmitsburg and Hanover, and all is quiet. I have not seen anything of General Couch's scouts. I will keep a sharp lookout in the direction of Hagerstown, as there is supposed to be a rebel force there.

Inclosed is also a copy of the instructions given this officer.

Very respectfully, your obedient servant,

HENRY H. LOOCKWOOD,

Brigadier-General, Commanding.

[Inclosure.]

HDQRS. THIRD SEPARATE BRIGADE, EIGHTH ARMY CORPS,
Baltimore, July 30, 1864.

Captain CHURCHMAN:

In accordance with the direction of Major-General Wallace, commanding the department, you will proceed, without delay, with your company to Middleburg and strengthen the patrols of the First Regiment Delaware Cavalry, now operating in that locality. You will take command of the whole patrol composed of your company, and the detachment of thirty men of the First Delaware Cavalry, unless that detachment shall be found to be commanded by an officer senior too yourself, in which event you will received orders from him. The country must be efficient patrolled between Libery and Middlebrug and as far up as Hanover, unless General Couch's cavalry is performing this duty in sufficient strength between Middleburg and Hanover. Captain Milligan will make frequent report by telegraph to these headquarters. A telegraph operator will be constantly on duty at Westminster and intermediate points between that place and Baltimore. In case of necessity, the cavalry patrol will retire in the direction of Baltimore, unless otherwise directed. Should you find an officer senior to yourself in charge of the patrol, you will communicate these instructions to that officer, who will carry them out to the letter.

By command of Brigadier-General Lockwood:

GEO. V. MASSEY,

Assistant Adjutant-General.

HARRISBURG, PA., August 6, 1864-3 p.m .

(Received 6.30 p. m.)

Major-General HALLECK,

Chief of Staff:

Lieutenant Thayer, signal officer at Greencastel, reported at 2 p. m. to-day that it was said a large force of the enemy's cavalry crossed at Williamsport yesterday and went in direction of Boonnsborough. One of his servants, sent to Fairview yesterday, is just in at Greencastle and says the force that crossed as above reported is from 6,000 to 8,000, with two batteries, mostly mounted. Was three hours in crossing. Hope my scouts at Emmitsburg will find out something of their direction.

D. N. COUCH,

Major-General.