THE SERVICE OF THE CORPS.

Of the importance of the service of the corps and of the benefits resulting to the general service from their action there are, at this office, only two means of judging-the demand for the services of the detachments of the corps and the official reports of services rendered. The demands for detachments have been proportioned as campaigns were active. In most of the great campaigns of the past year, however, the requisition for signal officers has been greater than it was possible to supply. In some instances the number required by generals in the field has been twice that which could be furnished; whilst representations made to generals commanding other military departments, with a view to withdrawing from such departments aa portion of the corps therein serving for duty elsewhere, have been met by the reply that the interests of the service required in those departments the continued presence of all signal officers there on duty.

I have the honor to submit the official reports and other papers bearing upon the operations of the corps, together with maps illustrating the positions, and such message reports as indicate the character of the duty; also a number of commendatory letters from military and naval officers.* These reports possess an additional value as exhibiting the requirements, as a class, of the officers who have been employed.

In considering the services of the corps it ought to be held in mind that wherever its officers have been actually on duty they rendered a service otherwise impossible; they have forced the enemy to introduce new elements into his calculations of military movements, and they have aided the commanders of our armies with an assistance at first novel to most of them. A few years ago the modes of communication-either those of aerial or electric telegraphy-constantly employed by these officers in the campaigns of the past year, would have been held mysterious, and the results almost miraculous. If they have made these modes common, and so constantly offered them for the use of generals that the results have ceased to longer excite surprise or comment, and if the duty is now held as something of course practicable with every army, it has become so through the energy and zeal of those upon it.

Aside from duties on land, to them eminently belongs the credit of that service, whatever may be its value, which has assured throughout this war the intelligent and certain co-operation of our land and naval forces whenever they have been present.

To contemplate the results of this labor and the absolute value of the services of signal officers in this war, it is necessary to consider in brief the facts as set forth in the accompanying reports.

In the first expatiation to Port Royal the rapid telegraphing among the vessels of the great armada which the service of these officers gave through its perilous voyage, were of the best results to the expedition. No modes approaching to its speed were previously known to general military use.

At the landing at Port Royal Ferry, where the U. S. troops first touched the mainland of South Carolina, their advance could be covered by the heavy batteries of the gun-boats, as it was, and necessarily, only by the service of the signal officers who accompanied them.

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*Papers and maps, herewith submitted, are published in Series I.

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