with the compact and perfectly transportable apparatus of the magnetic instruments of field trains, it promises a development of field telegraphy before impossible, and will favorably influence the telegraphy before impossible, and will favorably influence the telegraphic enterprises of the country. Should the experiments ordered warrant the course, the signal trains of the Army will be equipped with both the dial instruments already in use and the instruments now mentioned. There are opportunities for the employment of both. It is with some gratification that the attention of the Secretary of War is invited to these results. The credit of whatever success shall hereafter attach, in civil or military use, to American apparatus, based on these principles and on this style of its applications, will be largely due to that wise view of the War Department which first gave it opportunity for development.

During the past year there have been in the service of the corps thirty field trains, distributed as follows:

In the Army of the Potomac............................. 5 In the Department of the Cumberland.................... 5

In the Department of the Gulf.................. ....... 3

In the Department of North Carolina and Virginia........ 3

In the Department of the South.......................... 2

In the Department of the Tennessee...................... 6

In the Department of Ohio............................... 2

mp of Instruction,

Georgetown, D. C........................................ 3

At the United States Military Academy,

West Point, N. Y........................................ 1

----

Total...................................................30

Seventeen have been distributed since May 1, 1863. Of these trains some have been equipped with five and others with ten miles of insulated wire. There are carried in the trains lances for setting up the wire when that is necessary; reels, portable by hand, carrying wire made purposely flexible for this particular use, and various minor appliance which experience has proven useful. A military organization is directed for each train.

In duty of this kind the style of construction of the trains, the equipment they are to carry, and the military organization to be provided for their use, to enable them to be most rapidly and anywhere brought into action, are the subjects for study. The particular instrument to be equipped is for secondary consideration. The soldiers drilled to the duty of construction acquire in a short time a remarkable skill in the rapid extension of these lines. As was anticipated, they have proved valuable auxiliaries to the services of the corps, and have sometimes rendered them available when they would, without, have been impossible. The greatest reported distance at which the instruments have worked is something over twenty miles. The average distances at which they are used are from five to eight miles. The average speed of the most rapid construction is reported to be at the rate of a slow walk.

At the first battle of Fredericksburg field trains were first in the history of the war used on the battle-field under the fire of the enemy's batteries. The movements to be made on the day of that battle were of the first magnitude. The movement of the retreat were perilous to the whole army. The trains in use contributed some thing to the success of these movements.

At the battle of Chancellorsville several lines were extended. The shorter worked successfully; the longer failed. This failure was not, however, wholly the fault of the officer in charge: success cannot always be commanded.