Myers, chief quartermaster's department; Lieutenant Colonel J. M. Sanderson, chief of commissary department; Major D. C. Houston, chief engineer; Major D. Tillson, chief of artillery and ordnance; Surg. D. L. Magruder, chief of medical department. They will report at headquarters without delay.

JOSEPH HOOKER,

Major-General, Commanding Third Corps.

HEADQUARTERS OF THE ARMY,
Washington, September 7, 1862.

Brigadier General ANDREW PORTER:

GENERAL: You are assigned to duty in Pennsylvania to organize volunteers, and will report to Governor Curtin, at Harrisburg.

By order of Major-General Halleck:

J. C. KELTON,

Assistant Adjutant-General.

[Indorsements.]

DEAR MARCY: Here is the order from General Halleck. Please show it to the general, for any emendations he may think best.

Your friend,

A. P.

September 7, 1862.

I would respectfully suggest to General H[alleck] that it would be well to place General Porter in command of the troops now being raised in Pennsylvania, and to intrust to his charge the defense of Harrisburg and its approaches. I have fully explained to him the situation of affairs, and, in a general way, my intentions. He will do all that can be done to resist the advance of the enemy. I would also suggest that one of Peck's batteries and at least a squadron of good cavalry be placed under his orders.

GEO. B. MCCLELLAN,

Major-General.

HARRISBURG, PA., September 7, 1862-2 a. m.

Major General JOHN E. WOOL:

The following particulars have just come to hand. What can be done for the protection of our border?

CHAMBERSBURG, 6th.

ANDREW G. CURTIN:

Received full particulars concerning invasion of Maryland. Rebels arrived at Frederick City to-day at 11 o'clock, consisting of cavalry, 350; 19 pieces of cannon-1 howitzer (6-pounder), 610-pounder rifled cannon, and 12 ordinary pieces. Whole force seen amounted to 3,500. Were shoeless, unclad, taking possession of all stores having shoes, army goods, or other supplies, paying for the same Confederate scrip. Announced their destination Baltimore. Crossed at Noland's Ford. Jackson told an intimate friend of mine, living at Poolesville, he designed crossing into Pennsylvania, through Adams, York, and Lancaster, to Philadelphia. I believe he designs to invade Cumberland Valley, to procure supplies. Large numbers of persons came up on train to-night from Hagerstown.

A. G. CURTIN.

(Copy for Honorable E. M. Stanton.)