On the 16th, I reached Plymouth and had an interview with General Wessells and Captain Flusser. Some deserters had just arrived, and from them the following information was elicited in respect to Rainbow Bluff, &c.:

Three guns in embrasure to command the approach by river from below, one a rifled 32-pounder, others 24-pounders. One 24-pounder on field carriage in an angle of the fort sweeps the land approaches. There are also two brass 12-pounders and three 6-pounders playing over the breastworks. Rifle-pits on bank below fort 200 yards long. Five pieces field artillery in Hamilton, Graham's battery. Three companies, Pool's battalion, garrison the fort.

At Butler's Bridge, 2 miles from fort, are intrenchments and a place for one gun. Camp of Seventeenth Regiment [North Carolina Infantry], 1,100 strong, near the fort, and the camp of the Fifty-sixth Regiment [North Carolina Infantry] about 1 mile from Hamilton, from fort, and from Butler's Bridge. At Whitney's Bridge (River road), bride is destroyed, road barricaded, and breastwork 100 yards above. Five thousand men at Garrysburgh. Five hundred men at Edwards Ferry guarding the iron-clad, and iron-clad in course of construction.

These recent dispositions have resulted from your late raids, and will make it a matter of some difficulty to destroy the iron-clad at Edwards Ferry. For this enterprise from 800 to 1,000 good cavalry will be requisite. My plan would be to land the cavalry 6 or 8 miles above Plymouth,and move by Windsor, on an intermediate road, Roxebel, &c., since this route has been less used by our troops than the one via Winton. A demonstration from Norfolk, via Winton, upon Weldon at the same time, would materially enhance the chances of success.

I respectfully submit the above information and suggestions for your consideration.

Very respectfully, your obedient servant,

JOHN J. PECK,

Major-General.

[Indorsement.]

AUGUST 27, 1863.

Letter to be written stating that our force will not permit the proposed movement at present. Letter to be filed.

J. G. FOSTER.

CIRCULAR.] HDQRS. U. S. TROOPS IN CITY AND HARBOR,

[New York], August 17, 1863.

The duties of the United States troops in the city and harbor of New York are limited to the defense of the forts and the protection of public property, and of the officers of the General Government in the performance of their legal duties. The duty of maintaining order and protecting the properties and rights of private individuals devolves the municipal and State authorities, but the troops of the United States will be held in readiness to render any assistance that may be called for by proper authority,or be rendered necessary by the inability of the civil authorities to accomplish these ends.

The commanders of troops, both in the harbor and in the city, will make themselves fully acquainted with the duties they may be called