The development of the flash signaling, adopted in the British navy in 1867, was an adaptation of the Morse code to lights.
The first application of the telegraph in time of war was made by the British in the Crimean War in 1854, but its capabilities were not well understood, and it was not widely used.
Early signaling between naval vessels was by prearranged messages transmitted by flags, lights, or the movement of a sail.
Codes were developed in the 16th century that were based upon the number and position of signal flags or lights or on the number of cannon shots.
Military communication has thus long played an important role in warfare.
The railroad, the steamship, and the telegraph had a profound impact on logistic method during the last half of the 19th century.
In addition to its employment in spanning long distances under the civilian-manned military telegraph organization, mobile field service was provided in the Union army by wagon trains equipped with insulated wire and lightweight poles for the rapid laying of telegraph lines.
Immediately before and during the Civil War visual signaling also received added impetus through development of a system, applying the Morse code of dots and dashes, that spelled out messages with flags by day and lights or torches by night.
Messengers have been employed in war since ancient times and still constitute a valuable means of communication.Three years later, in the Indian Mutiny, the newly established telegraph, which was controlled by the British, was a deciding factor.In the American Civil War (1861–65), wide use was made of the electric telegraph.Another development for light signaling placed a movable shutter, controlled by a key, in front of a strong light.An operator, opening and closing the shutter, could produce short and long flashes to spell out messages in Morse code.