In all the campaigns of Generals Banks and Pope in the Valley of the Shenandoah and on the Rappahannock, the detachment of the corps-its officers, on one occasion, at least, serving within the enemy's limes and always active-won the regard of those generals, and sometimes determined great movements. He flank movement of Lee's grand army for the first invasion of Maryland is reported to have been first recognized from a signal station.
At the siege of Yorktown officers of the corps kept the communication with the navy lying some miles distant in the bay, while their stations of observation reached the James River.
At the battle at West Point, Va., without their aid the naval broadsides could not have been turned, as they were, against the enemy, but must have been largely wasted at random.
Before Richmond, at Williamsburg, and at White House they were constantly on duty, and their services were frequently important.
On the battle-field at Malvern Hill the aid of signal officers subjected to control, from land, the fire and movement of the fleet through both days" battle. It is difficult to compute the value, there, of this service, whilst, thenceforth, throughout all the service of the land and naval forces on the Peninsula their aid was in requisition.
At South Mountain and Antietam signal officers won, by their conduct and the value of their services, the commendation of the general there commanding.
In the first attack on Fredericksburg, and in the long campaign before that city, they had, for their efficiency, the praise of General Burnside.
In the movements at Chancellorsville, crippled as the corps was by the failure (through no fault of its members) of some of the apparatus, they rendered such service, as that may be, which kept ut the communication with General Sedwick's Sixth Army Corps- at that time utterly cut off from the main body of the army and from headquarters-over the heads of the rebel forces, and when, the retreat being ordered and the army falling back in the night upon the river, the pontoons on the right wing of the army were swept away, a message went, by their aid, across the swollen river to hold the army in its lines instead of crowding it, with danger of a panic, on the banks of a torrent it could not cross.
In the movements to Gettysburg the field telegraphic lines and the signal stations apart in front of Washington, and orders went from corps to corps when the enemy's cavalry prevented the passage of couriers, and even contested with heavy escorts. If all the services of the corps in this campaign to Pennsylvania thus expedited the movements of our army by one day to reach the field of Gettysburg, that service alone was worthy of consideration.
When the rebel army in this campaign, recrossing the Potomac, hesitated at Martinsburg, as if to return to Maryland, and the Army of the Potomac east of the Blue Ridge was held uncertain of the enemy's intentions, the information obtained, and which went far to show, if it did not of itself fix their course, elicited for the corps the thanks of the commander of our army.
In the now (October 30) just finished movement of the rebel army threatening the right of the Army of the Potomac, near the Rappahannock, it is stated that the first report of the enemy's design was made from the signal station on Thoroughfare Mountain many hours before the counter movement of our army was needed.