HEADQUARTERS ARMY OF THE POTOMAC,
September 20, 1862--3 p. m.

Major-General HALLECK,

General-in-Chief, Washington:

I urgently request that the president of the Chesapeake and Ohio Canal Company be asked to repair that canal at once. That he should do so is indispensably necessary for ulterior military operations. I also request that all the small steamers plying on the canal may be sent to Harper's Ferry as soon as the repairs shall have been completed. By my direction my chief quartermaster telegraphed last evening a dispatch similar to this to General Meigs, who replied raising objections on the score of want of protection to the canal. I do not require suggestions of this kind. I shall be responsible that full protection is afforded it.

G. B. McCLELLAN,

Major-General, Commanding.

[19.]

HEADQUARTERS ARMY OF THE POTOMAC,
Centerville, September 20, 1862--9 a. m.

Major General F. J. PORTER,

Commanding Fifth Corps:

GENERAL: The reason why no cavalry reported to you this morning is that last night they were ordered by you back to their old camps to refit and to shoe their horses, much to the surprise of the commanding general. They were ordered out last night, and it is presumed must have reported to you before this time. General Couch's division and two brigades of cavalry have gone to Williamsport this morning to attend to a rebel force said to be in possession of and opposite to that town.

Yours, very respectfully,

R. B. MARCY,

Chief of Staff.

[19.]

HEADQUARTERS ARMY OF THE POTOMAC,
Centerville, September 20, 1862--11 a. m.

Major General W. B. FRANKLIN,

Commanding Sixth Corps:

GENERAL: The commanding general directs that you put your command in readiness to move at a moment's notice and with as little delay as possible. General Porter reports that the enemy are attacking his position on the other side of the river, at Shepherdstown.

Yours, very truly,

R. B. MARCY,

Chief of Staff.

[19.]

HEADQUARTERS ARMY OF THE POTOMAC,
Near Sharpsburg, September 20, 1862--8.30 p. m.

Major General W. B. FRANKLIN,

Commanding Sixth Corps:

GENERAL: An aide of General McClellan's has just returned from General Couch's position near Williamsport. The information he brings is of such a character as, in the opinion of the commanding general, to