The progress is very satisfactory in view of the limited force and the unfavorable state of health. A number of heavy guns have been mounted at important points, and two companies Rhode Island artillery have been placed at Washington. The river obstructions have been delayed by high water and other causes. General Wessells will press this branch of defense as fast as possible. I attach much importance to it, situated as it is with respect to the water battery, Fort Gray. This mode of blockading rivers is generally adopted by the rebels.

In reply to a communication of mine upon the subject of torpedoes, General Foster suggested an officer of the navy as being experienced in their construction. Commander Davenport, U. S. Navy, reports that he has no one acquainted with the use of torpedoes. In my judgment, they are very unreliable, and would afford but an uncertain defense at the port of Plymouth.

The suggestion in the letter of General Foster, of the 24th of April, for substituting black labor for white in the District of the Albemarle is a good one, and I shall address General Wessells on the subject.

My expectations in respect to the colony were more than realized by my visit to Roanoke Island. No better place could have been selected, and I see no permanent cause for apprehension on the score of health. The superintendent is actively engaged in laying out the streets and lots. My instructions were to make the avenues of ample width, with a view to increase the beauty and healthfulness of the island. Mules, horses, wagons, &c., have been condemned and ordered to be turned over to the colony. The success of the enterprise I regard as certain, and believe that this African colony can be made self-supporting after the first year.

It is with regret that I learn we are not to be re-enforced in North Carolina and Virginia.

I am, very respectfully, your obediet servant,

JOHN J. PECK,

Major-General.

HEADQUARTERS ARMY OF THE POTOMAC,
October 3, 1863-4. 30 p. m. (Received 5. 20 p. m.)

Major-General HALLECK:

Reliable intelligence from scouts and deserters would indicate that Lee has been considerably re-enforced within the last week. Cooke's brigade has come from Richmond, and the brigade of Pickett's division left at Drewry's Bluff; also a brigade of North Carolina troops are reported arriving at Orange Court-House, but from whence not known. Intercepted messages, and increased forces at various parts of the enemy's line, together with other indications, would seem to point to some movement on their part, whether a mere raid to intercept my communication, or a reconnaissance in force to ascertain my position and numbers, remains to be seen.

Yesterday 2 of our men came across a party of rebel scouts, 4 in number, in the woods within our lines. One man was killed on each side, when the rebels escaped, after wounding our second man.

Lee, advised of the detachment of this army is undoubtedly anxious to ascertain its strength. The army remains in the same position as last reported, principally massed around Culpeper Court-House, with