GRAFTON, June 28, 1861.

Lieutenant General WINFIELD SCOTT,

Washington:

From information received to-day, I renew request that two Pennsylvania State regiments, new near Cumberland, be directed on Cumberland and Piedmont. If possible, some guns and cavalry. If Piedmont unprotected, almost certain town will be ruined by rebels and railway destroyed. I cannot now spare necessary force. The movement will materially all bridges except two between Harper's Ferry and Cumberland. If possible, will do same up to Cheat River. Forty-five engines and over four hundred cars destroyed at Martinsburg.

GEO. B. McCLELLAN,

Wiliamsport, June 28, 1861-8 p. m.

Colonel F. J. PORTER,

Asst. Adjt. General, Hdqrs. Dep't of Pa., Hagerstown, Md.:

COLONEL: I have just received the inclosed letter from General Negley, saying that he is informed the enemy are preparing to cross the river at Harper's Ferry. I have no reason for doubting the fact, other than I think their main force is near Bunker Hill, say 7,000 or 8,000 men, and the remainder, with perhaps the greater part of the artillery and cavalry, south of Falling Waters, say perhaps 5,000 men. The artillery, said to be seventeen 6-pounders, are refiled brass pieces, as is said by an intelligent deserter here and confirmed by one other source. I have written to General Negley to say I will support him at once on hearing that the enemy have actually crossed the river.

Very respectfully, your obedient servant,

CADWALADER,

Brevet Major-General, Commanding.

[Inclosure.]

HEADQUARTERS FIFTH BRIGADE, Camp Newton, Md., June 28, 1861.

Colonel F. J. PORTER:

DEAR SIR: I am this moment reliably informed that the enemy are preparing to corss the river at Harper's Ferry. They moved a force from the Ferry this morning (3 a. m.) towards Shepherdstown. This force was replaced about 9 o'clock a. m. They were engaged during the morning loading some army stores at the railroad. The second messenger informed me as above.

I have the honor to be, sir, your obedient servant,
JAMES S. NEGLEY,

Brigadier-General, Commanding.

I have sent a squad of dragoons to Harper's Ferry for further information.

[Indorsement.]

HEADQUARTERS DEPARTMENT OF PENNSYLVANIA, Hagerstown, Md., June 28, 1861.

Respectfully forwarded to the headquarters of the Army. The enemy have collected in large numbers on the Virginia side of the Potomac.