HEADQUARTERS DEPARTMENT OF THE SHENANDOAH,
Near Hyattstown, Md., August 21, 1861.

Colonel LEONARD, Thirteenth Massachusetts Regiment:

SIR: In view of instructions, received this day from headquarters of the Army in Washington, it becomes necessary for you to take post in the vicinity of Harper's Ferry. The Commanding General direct that you proceed with your regiment to Sandy Hook, and to take post on the Maryland side of the Potomac, so as to prevent an enemy from crossing at the ford or ferry, and to hold the Maryland Heights.

Very, respectfully,

ROBT. WILLIAMS,

Assistant Adjutant-General.

HEADQUARTERS OF THE ARMY,
Washington, August 22, 1861.

Major-General MCCLELLAN, U. S. A.,

Commanding Department of the Potomac:

SIR: The General-in-Chief directs me to say that, on information considered by the War Department as important and reliable, orders were given to Major-General Dix, commanding in Baltimore, to stop, until further orders, all boats between Baltimore and Saint Mary's or the neighboring counties of Maryland and Virginia. This order was given the 15th instant. Permission was given the 18th for a steamboat to make one trop to bring away families left behind.

The Honorable Reverdy Johnson, of Baltimore, proposes that the boats shall be permitted to renew their trips for the purpose of carrying freight only, without the privilege of taking passengers, under such guard or regulations as may be necessary for the public safety. The object of this arrangement would be to enable the loyal people of Maryland to send their produce to the Baltimore market, as they have been in the habit of doing. The General-in-Chief wishes you to refer this proposition to Major-General Dix, and if he thinks well of it, to have it carried into effect.

I am, sir, very respectfully, your obedient servant,

E. D. TOWNSEND,

Assistant Adjutant-General.

SENECA, August 22, 1861.

Major S. WILLIAMS,

Asst. Adjt. General, Hdqrs. Division of the Potomac:

MAJOR: I have the honor to report, for the information of the Major-General Commanding, that all is quiet throughout my lines; no change opposite.

This morning there was cannon firing near Leesburg, either two salutes or practicing; more probably the latter.

General Banks is at Hyattstown, some 9 1/2 or 10 miles northeast of Poolesville, connecting with my position by a reasonably good road, and with Rockville by and excellent one.

I fear there is too much nervousness on my right-that is, in the command of Colonel Geary, at Point of Rocks. His ambulances came hastily into my camp this morning, having been sent off at 10 p. m. last night. The river is nor fordable for wagons or artillery at this time.