Confederate Congress, that this line, hitherto left wholly to its own feeble resources, and directly in front, as it is, of the enemy's massed force at Washington, should immediately be put in an adequate attitude of defense by such exterior aid or re-enforcements of Southern troops as have been heretofore withheld from this line, while they have been concentrated at Richmond, Norfolk, and Harper's Ferry, leaving absolutely at the mercy of the enemy the town of Alexandria, the gallant little band which now holds that post, and the whole system of railroads which, debouching form Alexandria, penetrates this noble country to its very heart, connected with the valley and strategically with Harper's Ferry, and thus laying bare the very vitals of the State to a deadly attack or to a stunning blow. Verbum sap. The hour for closing the mail is at hand, and the General-in-Chief will pardon the imposition of this. Germane subject will be pursued in the next following dispatch.

Very respectfully, your obedient servant,

PHILIP ST. GEO. COCKE,

Colonel, Commanding Potomac Department.

HEADQUARTERS POTOMAC DEPARTMENT,
Culpeper Court-House, Va., May 14, 1861.

Colonel R. S. GARNETT, Adjutant-General:

SIR: I communicate herewith a paper for the information of the General-in-Chief, which may have a significance of some interest just at this juncture. I would also communicate to the general that I was yesterday informed by Major Brent, Virginia volunteers, and direct from Alexandria, that the enemy is prolonging himself along the canal, and has already reached Monocacy with his advanced post, which points is at the junction of the Baltimore and Ohio Railroad with the canal, so that already Colonel Jackson's vedettes may be in sight of the enemy. Some of my cavalry being without pistols, I would be glad if they could be provided with lances.

Very respectfully, your most obedient,

PHILIP ST. GEO. COCKE,

Colonel, Commanding Potomac Department.

[Inclosure.]

WASHINGTON HOME GUARD OF CAVALRY,

May 13, 1861.

Lieutenant-Colonel TERRETT,

Commanding Post at Alexandria, Va.:

My vedettes of Saturday and Sunday reported "that, while upon their station, near the Aqueduct, at Georgetown, at noon of each day, they were fired upon from Georgetown, the balls striking the trees near them, forcing them to change their position, when the firing was repeated upon their new position." To-day, with five men, selected and well armed, I proceeded upon the tow-path, on the Aqueduct, to the middle, when I summoned the corporal of the U. S. guard, and demanded an explanation of the firing. He stated that it was not from his men. His orders were to stop supplies, suspicious persons, and to act upon the defensive. I then sent a messenger to the mayor of Georgetown, demanding and explanation of him. Received in reply, through superintendent of police, that the corporate authorities would punish