SIGNALING AND TELEGRAPH ING, MILITARY. The art of trans mitting information by visual signals is of very ancient origin, and has, no doubt, been practiced by all races in every part of the world. The simplest form of sig nal is, probably, the beacon fire, used for centuries to warn neighboring tribes of the approach of enemies and for other purposes. Very early in history, how ever, the art of signaling for military purposes reached a high stage of devel opment, and even in these days of teleg raphy, telephony and wireless telegraphy, communicating by visible signs still has its uses. In the modern army, the stand ard equipment used for signaling is a flag attached to a light pole, but any other easily visible object may be used, a torch or lantern being employed at night time. The two systems most commonly used are the Morse code and the Myer code. The former makes use of a system of dots and dashes, a definite number of dots and dashes representing each letter of the al phabet. Thus, a is represented by • —, b by—..., and so on. The signaler holds his flag perpendicularly, and to send a message moves it through an angle of 45 for a dot, or of 90 for a dash. The Myer
system represents each letter of the al phabet by a series of numbers. Thus, a is 22, b is 2112, c is 121, and so on. The signaler holds his flag perpendicularly, and then moves it through an angle of 90 to the right for 1, 90 to the left for 2, and straight down in front of him for 3.
The heliograph signals by means of a mirror, or a combination of two mirrors, reflected sun flashes taking the place of movements of a flag. When the sun is in front of the operator, only one mirror is needed. When the sun is behind the operator, two mirrors are required, one to reflect the sun from the first mirror to the second, the other to reflect it from the second mirror to the receiver.
Military telegraphy differs in no essen tial from ordinary telegraphy, but special equipment is, of course, required. The wires are strung on light poles, or may even lie on the ground. They are car ried on a reel, supported either on a man's back or on a light cart. Wireless teleg raphy is rapidly rendering the use of a cable unnecessary.