Signaling
TELEGRAPHING The first commences at the point of the equator through which the sun passes at the time of the vernal equinox; and they are counted onward, proceeding from W. to E., according to the annual course of the sun, all round the circle. The names of the 12 signs, in the order in which they follow each other, are as follows: Aries, Taurus, Gemini, Cancer, Leo, Virgo, Li bra, Scorpio, Sagittarius, Capricornus, Aquarius, Pisces. It is to be remarked that the above are also the names of the 12 constellations of the zodiac; and in ancient times (more than 200 years before our era), the places of the signs and the constellations were coincident; but owing to the motion of the earth's equator, by which the equinoctial points are carried backward on the ecliptic about 50' 6" annually, the intersections of the ecliptic and equator, and consequently the com mencement of the signs, now correspond to different stars, the first point of the sign Aries being at present near the beginning of the constellation Pisces. On this account care must be taken not to confound the signs of the zodiac, which are fixed in respect of the equinoxes, with the constellations, which are movable in respect of those points.
In algebra, a symbol indicating an operation to be performed, or a relation subsisting between two quantities. Of the former kind, those most commonly used are, + for addition, - for subtraction, X for multiplication, for division, V for the cube the square root, 3V for the cube root, ny for the nth root, etc. The sign denoting relations are, = equal to, > greater than, less than, etc. SIGNALING AND TELEGRAPH- ING, MILITARY. The art of transmitting 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 signal 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 telegraphy, telephony and wireless telegraphy, communicating by its uses. In the modern army, the stand- . In the modern army, the standard 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 communicating by visible signs still has SIGNALS 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 alphabet 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 essential 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 carried on a reel, supported either on a man's back or on a light cart. Wireless telegraphy is rapidly rendering the use of a cable unnecessary.