My last reported the operations of the detachment to the 9th ultimo. During the active campaign preceding the investment of Vicksburg the party serving with the army in the field accompanied it in all its marches from Grand Gulf through Port Gibson, Raymond, Black River Bridge, Jackson, and Champion's Hill to the immediate rear of Vicksburg. The country through which the route of the forces lay is generally flat and wooded, and unsuited to any extensive lines of communication by signals, and, pursuant to suggestions contained in the last annual report of the Signal Officer of the Army, the party was employed almost wholly in reconnoitering. The party was divided into four detachments, one of which was kept at General Grant's headquarters and one at each of the three corps headquarters.

From the detachment kept at general headquarters an officer was sent each day of the corps headquarters with instructions to obtain the result of the observations made the same day by the detachments assigned to the respective corps d'armee, and to report the same each evening to Major-General Grant in person.

The detachments with the various army corps were engaged each day in reconnoitering in advance, and reported by signal or courier, as was found most expedient, the result of all observations worthy of notice to the general commanding the corps. Thus each corps commander was kept well informed as to his own command and General

Grant as to the whole army. The credit of this of this arrangement is due to Captain De Ford.

Upon the arrival of the army at the rear of Vicksburg, Captain De Ford caused communications to be opened form Snyder's Bluff, where the right of the army rested, to Admiral Porter's flag-ship, lying in the Yazoo, a distance of 4 or 5 miles. The station on the bluff was occupied by Captain McClintock and Lieutenant Magner. They did, and are still doing, valuable service. A line was also established from General Grant's headquarters to the extreme left, but the peculiar topography of the country necessitated so many stations that, in the opinion of Captain De Ford, this line was nearly useless, as a courier could ride over the line in less time than a message could be transmitted in the usual manner. He consequently recalled the officers stationed on this line. The resignation of Captain De Ford at this time placed Captain Rose in command of the party, he being the senior officer present. Captain Rose immediately re-established the line to the left, together with some other important lines.

The following is a copy of a report received form him, showing the present locations of the lines and the operations of the party since he assumed command:

HDQRS. SIGNAL DETACHMENT, ARMY IN THE FIELD, DEPT. OF THE TENN.,
Rear of Vicksburg, MISS., May 31, 1863.

SIR: I have the honor to report that this detachment has, since I assumed command, been doing good service, having been at work almost constantly day and night. We have now three lines in good working order, and officers and men are all taking an interest in their duties.

Our line to Haynes' Bluff is of the greatest importance, as it the only means of communication with the two DIVISIONS of our troops in that part of the country, stationed there to observe the movements of General Johnston's forces in our rear. The best officers I have are on this line, and it works to a charm.

The line from General Grant's headquarters to Young's Point, La., is of the utmost importance; it is the means of communication between the army and the navy. Admiral Porter is highly pleased with the corps.

The line from General Grant's headquarters to the Yazoo Landing, the depot of supplies for the use of the medical, commissary, quartermaster's, and ordnance departments, is, of course, of much utility.