Numbers 7. Report of Captain Paul Babcock, Seventh New Jersey Infantry, Acting Signal Officer, U. S. Arm, of operations October 17-November 6.

HEADQUARTERS FIFTH ARMY CORPS, November 7, 1862.

LIEUTENANT: In obedience to orders from the Chef Signal Officer, Army of the Potomac, I have the honor to make the following report:

On the 17th October I reported to Major-General Porter, at Sharpsburg, Md., Lieutenant Thomas R. Clark and 4 men being with me ready for duty. General Porter immediately informed me of two points with me of two points with which he desired communication, viz, Headquarters Army of the Potomac, and a point on the Potomac Rover overlooking a ford, over which he hourly expected a division of his troops. I immediately told him but ore of the communications could be established that night, as there were but two officers in my party. Twenty-five minutes after his decision which to do, communication was established between his headquarters and the point indicated. Fifteen messages passed between the two points up to the time when Lieutenant Clark reported the division approaching the ford in good order, and no signs of any enemy. Upon receipt of this message, the general pronounced the station no morning (October 18) we opened with the station at White House, thus connecting General Porter with general headquarters. From this date to October 28 (the day on which you request a full report to commence), we kept General Porter in uninterrupted communication with the White House station, on Elk Mountain, the station of observation on Maryland Heights, and through it with headquarters Army of the potomac, constantly receiving from Lieutenants Pierce and Fuller at one and Lieutenants hall and Taylor at the other full and accurate reports of the positions and movements of the enemy, often in advance of any other, and generally confirmatory of that received from other sources. These reports seemed of great importance to the general, and he seemed much pleased with the facility and accuracy with which they were obtained. In addition to the foregoing, we frequently took observations from the river bank, and reported to General Porter the apparent position, force, &c., of the enemy opposite. On one occasion, Lieutenant Clark made such a report, upon which the general sent over and captured some 10 or 12 of their pickets. From October 28 to 30 we continued as before, and, i believe, to General Porter's entire satisfaction. October 30, at 3.30 p. m., we broke up camp and followed General Porter to Pleasant Valley, almost directly under the Maryland Heights station. Here we tried-to communicate with maryland Heights, but all our efforts were fruitless. Rockets and red lights were burned, and the torches swung from 7 to 11.30 p. m., and within 3 miles of the station, but no answer could be gotten. Fortunately we were not called upon that night to sent any messages. Next morning, October 31, we moved with the general, and encamped at Sandy Hook, within 2 1/2 miles of maryland Heights station. We immediately proceeded to open with them, and tied both large flags to the long pole, swinging for two hours without an answer, when I sent a man up to notify them of our position. They then saw us with naked eyes. At their request, we read their reports to General McClellan and gave them to General Porter. These reports were very full and important, and reflected great credit on Lieutenants Hall and Taylor.