y Signals-Code Fla

aphs-Ardois Signal

mmander needs some better way of communicating with the ship captains than despatching a messenger in a small boat. The n

on as a naval arm. The use of signal-guns was soon thought of, and war-ships used their guns for signal purposes as early as the sixteenth century. Not long

be conveyed. Unlimited communication at a distance was still impossible, and there were no means of sending a message to meet an unforeseen emergency. So cumber

and all messages. It is not clear whether Admiral Sir William Penn or James II. established the code. It was while he was Duke of York and the commander of Britain's nav

varied positions of a single signal. From his plan the flag signals now in use by the navies of

night-signal system of flashing lights, still in use to some extent, and which bears his name. Colomb's most important contributio

le message by simply hoisting letter after letter. So slow a method is seldom used, however. Various combinations of letters and figures are used to indicate set terms or sentences set forth in the code-book. Thus the flags representing A and E, hoisted together, may be found o

e of the sea, and by it sailors of different tongues may communicate through this c

lphabet are indicated by the positions in which the signaler holds his arms. Keeping the arms always forty-five degrees apart, it is possible to read the sig

g mounted at the masthead. The semaphore as a means of communication was extensively used on land commercially as well as by the army. A regular semaphore t

aph, 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 communic

nd 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

code has been applied. This instrument catches the rays of the sun upon a mirror, and thence casts them to a distant receiving station. A small key

he sole means of communication between besieged garrisons and the relief forces. Where no mountain ranges interve

ituated at a convenient point on the deck. A red lamp is flashed to indicate a dot in the Morse code, while a white lamp indicates a dash. The Ardois system is also used by the Army. The perfection of wireless telegraphy has caused the Ardois and other signal systems depending upon sight or sound to be discarded in all but exceptional cases. The wig-wag and similar systems wi

of similar nature. This is the submarine signal. We have noted that much attention was paid to communication by sound-waves through the medium of the air from the

reat river. The general alarm and the impossibility of detecting the approach of another vessel set Mundy thinking. It seemed to him that there should be some way of communicating through the water and of listening for sounds underw

ndred-pound bell twenty feet beneath the surface of the sea. A receiving apparatus was located three miles distant, which consisted simply of an ear-trumpet connected to a gas-pipe lowered into the sea. The lower end of the pipe was sealed with a diaphragm of tin. When submerged six feet beneath the surface the

nected to the two microphones are mounted close together on an instrument board on the bridge of the ship. The two instruments are used when it is desired to determine the direction from which the signals come. If the sound is stronger in the 'phone on the right-hand side of the ship the commander knows that the signals are coming from that direction. If the signals are from a ship in distress he may proceed toward it by turning his vessel until the sound of the signal-bell is equal in the two receivers. The abili

war-ships. By this means alone may a submarine communicate with

n enemy submarine. But it was found that by means of the receiving apparatus of the submarine telephone an approaching submarine could be heard and located. While the sounds of the submarine's machinery are not audible above the