BALTIMORE, September 6, 1862.

Brigadier General JULIUS WHITE, Martinsburg:

Defend yourself to the last extremity. No running before the enemy is coming. Reconnoiter.

JOHN E. WOOL,

Major-General.

BALTIMORE, September 7, 1862.

Brigadier General JULIUS WHITE, Martinsburg:

If 20,000 men should attack you, you will, of course, fall back. Harper's Ferry would be the best position I could recommend; but be sure that you have met such a force, or any other that would over-whelm you. All surplus property will be ready for instant removal, should you find it absolutely necessary to abandon Martinsburg. No property will be destroyed if by any means it can be saved.

JOHN E. WOOL,

Major-General.

HARPER'S FERRY, September 7, 1862 - 2.30 a. m.

Major-General WOOL:

The enemy is steadily pressing on my pickets from Point of Rocks; has driven them in to Sandy Hook, and is putting batteries in position on a plateau opposite. I am ready for them.

D. S. MILES,

Colonel Second Infantry.

BALTIMORE, September 11, 1862.

Honorable F. H. PEIRPOINT, Governor of Virginia, Wheeling, Va.:

I would not, under the present uncertain state of affairs, feel justified in removing from Harper's Ferry or Martinsburg any of the forces stationed there.

JOHN. E. WOOL,

Major-General.

HARPER'S FERRY, September 16, 1862.

Major-General WOOL:

I have the honor to state that this place has been defended for several days against an attack by the divisions of Jackson, A. P. Hill, Lawton, Walker, and McLaws, amounting in all to at least 40,000 men, with over fifty pieces of artillery. After expending all our artillery ammunition, except that for short range, and defeating two attacks of the enemy's infantry, Colonel Miles, with the advice of his brigade commanders, reluctantly surrendered. I regret to say that the gallant Colonel Miles is so severely wounded that his recovery is not probable. I march to-day with the command, and will report to you, in detail, the events which have occurred since my last communication.

JULIUS WHITE,

Brigadier-General.

When I was at Harper's Ferry in August, I gave verbal orders to Colonel Miles in regard to the intrenchments there. He had not completed the intrenchments, and I directed him how it should be done. He had not made embrasures, and I told him to do it immediately, in order that his men might be able to ascertain how to direct their guns. I directed him also to build an intrenchment on Bolivar Heights. After-ward, by a written order which I do not see here, finding that he had not done so, I directed him peremptorily to intrench Bolivar Heights, and to abatis Camp Hill, which he, however, neglected doing. He also neglected to build a block-house on Maryland Heights, which I had directed him to build. When I gave him the order to punish the enemy coming in the direction of Harper's Ferry, I supposed he then had the block-house finished. Soon after, however, Major Rodgers came down and informed me that Colonel Miles gave no countenance to it.

Question. He had ample time and ample means for complying with both these orders?

Answer. Yes, sir; it was in August that I first gave orders in regard to Bolivar Heights and abatising Camp Hill. I also directed him to place a battery of six pieces in the road in front of Harper's Ferry bridge. After they had exhausted their firing, it was to be presumed that they might occupy the heights, and when they should commence the assault they would probably have to come down that road to attack Camp Hill. I ordered him to place a battery of six pieces there, and pointed out the place to him, and he promised to do it. He seemed to be very zealous at the time, and determined to do everything; but I am inclined to think he was overwhelmed with his duties, and perhaps had not the capacity to embrace so important a command as that. But he was the best officer I had. It was my determination to have gone up there myself, if there should be merely an attack on Harper's Ferry; but having the command of the two places, I thought Baltimore the most important. And I had anticipated that a force would be sent from Washington sooner than it was. If Colonel Miles had held out there for a few hours longer, I have no doubt General McClellan would have re-enforced him. At any rate, my opinion was that 10,000 men could have defended that place against 40,000, and I do not think the enemy had half that number; not over 30,000, at all events. I have not been able to determine from any accounts I have had that the enemy had the number reported. Colonel Miles had 13,000 there at first, but he sent away 1,500 cavalry.