of communication was extensively used on land commercially as well as
by the army. A regular semaphore telegraph system, working in relays
over considerable distances was in operation in France a century ago.
Other semaphore telegraphs were developed in England.

The introduction of the Morse code and its adaptation to signaling by
sight and sound did much to simplify these means of communication. The
development of signaling after the adoption of the Morse code, though
it occurred subsequent to the introduction of the telegraph, may
properly be spoken of here, since the systems dependent upon sight and
sound grow from origins more primitive than those which depend upon
electricity. Up to the middle of the nineteenth century armies had
made slight progress in perfecting means of communication. The British
army had no regular signal service until after the recommendations
of Colomb proved their worth in naval affairs. The German army, whose
systems of communication have now reached such perfection, did not
establish an army signal service until 1902.

The simplicity of the dot and dash of the Morse code makes it
readily available for almost any form of signaling under all possible
conditions. Two persons within sight of each other, who understand
the code, may establish communication by waving the most conspicuous
object at hand, using a short swing for a dot and a long swing for a
dash. Two different shapes may also be exhibited, one representing a
dot and the other a dash. The dot-and-dash system is also admirably
adapted for night signaling. A search-light beam may be swung across
the sky through short and long arcs, a light may be exhibited and
hidden for short and long periods, and so on. Where the search-light
may be played upon a cloud it may be seen for very considerable
distances, messages having been sent forty miles by this means.