CAMDEN STATION, July 7, 1864. (Received 8. 40 p. m.)

Major-General AUGUR:

I presume no apology is necessary for my repeating to you the substance of my first warning of last night about the inadequacy of the guard upon the important bridges of our railroad between Annapolis Junction and Washington, which I understand has not been to-day increased. I have now to inform you that the enemy is actually within forty miles of these points in force, and to suggest that the force at any of those points is too slender to resist any earnest cavalry attack.

W. P. SMITH,

Master of Transportation.

HDQRS. DEPT. OF WASHINGTON, 22nd ARMY CORPS, July 7, 1864.

General DE RUSSY,
Commanding at Arlington:

Quite a large force of rebel cavalry are reported in the vicinity of Dranesville with artillery. Send an officer at once to Fort Ethan Allen to notify them and to see that all is right there. Let him look to the bridge (Chain) also, at both ends of it. Have the cavalry there ready for instant service.

C. C. AUGUR,

Major-General, U. S. Volunteers.

ARLINGTON, July 7, 1864-10. 40 p. m. (Received 10. 20 a. m. 8th.)

Major-General AUGUR,

Commanding Department of Washington:

Your telegram this moment received. An officer is dispatched to order the bridge taken up at Chain Bridge, and to prepare the command in case of attack.

G. A. DE RUSSY,

Brigadier-General of Volunteers.

Line to Arlington was out of order after telegram to General De Russy was sent last night.

OPERATOR.

ALEXANDRIA, July 7, 1864. (Received 9. 05 p. m.)

Colonel TAYLOR,

Chief of Staff:

COLONEL: The patrols report a large of the enemy near Dranesville with two pieces of artillery, under command of Mosby and Major Gilmor. They also report about 150 of Colonel Lowell's command captured near Aldie.

H. H. WELLS,

Lieutenant-Colonel and Provost-Marshal-General, Defenses South of the Potomac.