HEADQUARTERS FOURTH ARMY CORPS, Yorktown, April 16, 1863.

Major-General DIX,
Commanding Department of Virginia, Fort Monroe:

The enemy's pickets are in Williamsburg, and Governor Wise's troops have taken and paroled as prisoners of war two cavalrymen who were acting as nurses to the insane--to those whom Governor Wise styled Virginia's "little ones," and as belonging to a "hospital the most exempt of all from the least touch of war." I have ordered Dr. Wager and the two paroled cavalrymen to withdraw from the asylum.

E. D. KEYES,

Major-General.

FORT MONROE, VA., April 16 1863. (Received 6 p. m.)

Major General H. W. HALLECK,

General-in-Chief:

I send a dispatch from General Foster of the 12th. I have one from General Palmer of the 15th saying that a river steamboat, which supplies of provisions and ammunition and a regiment, had run the blockade, and was safe at the wharf at Washington the 14th:

FORT WASHINGTON, N. C., April 12, 1863.

Major General H. W. HALLECK:

GENERAL: I have the honor to report that no very material change in the position of opposing forces around this town has taken place since the date of my letter of the 5th instant. The enemy has been constantly at work erecting batteries, and now has in full operation six batteries, mounting seven guns, on this side of the river, north side of the town, and three batteries, mounting six guns, on the south side of the river opposite the town. Added to these are the batteries erected to prevent boats coming up the river, some miles down. The guns are, however, mostly rifled, of small caliber, none being larger than 20-pounder Parrotts, except one 32-pounder smooth-bore. The works of the defensive have kept pace with the offensive, being always a little ahead, and the result of each day's firing has been the silencing of the enemy's batteries, forcing them to withdraw their guns from sight. The firing on both sides is quite sharp for a short time each day. No killed or wounded since my last letter. The force that I directed to march for my relief from New Berne has not as yet exhibited any result. General Palmer reports that the advance guard left New Berne on Wednesday under General Palmer reports that the advance guard left New Berne on Wednesday under General Spinola. The latter general was under the impression that the whole force in his front was 16,000 men, double his own force. I increase to 10,000 men; also for General Nagle, who has been ordered to report to me. He hurried off as soon as possible to take command of the operating force. I am confident that I can hold out here provided I am supplied with ammunition and provisions form below. There is no great difficulty in supplying us by means of vessels and boats running the gauntlet of the batteries; and although the gunboats and our transports have not as yet fulfilled our expectations in this respect, yet I am informed by General Palmer that arrangements are now made to send me supplies of men and ammunition. I do not intend to yield one inch on any point if I can in any way prevent it, and shall therefore contest the occupation of this place until General Hill is forced to withdraw. I beg that you will look favorably upon my application for re-enforcements, unless the necessities of the service forbid it, for without them some disaster to our arms may occur in this department. The enemy's numbers are fully equal to the representations in my letters of last month, and from their movements I am confirmed in my opinion that as soon as the main army is forced to evacuate Virginia the field of operations will be this State; hence their efforts to obtain possession of the eastern counties, which are the most fertile in the State.

J. G. FOSTER,

Major-General, Commanding.

JOHN A. DIX,

Major-General.