Page:The New International Encyclopædia 1st ed. v. 18.djvu/192

* SIGNALING AND TELEGRAPHING. 154 SIGNALING AND TELEGRAPHING. near the instrument; and upon the right aud left there should be also a solid fence of about 10 feet in length and of the height of a man, that the torches, being raised along the top of those ramparts, may give a more certain light, and when they are dropped again that they may also be concealed behind them." Signals are either transient or permanent: transient w'hen each element disappears upon completion; permanent when the signal is the combination of certain arbitrary elementary indi- cations, e.g. sounds, colors, forms, etc., in ac- cordance with fixed rules, known both to the sender and receiver. The elementary indications are called primary signals. The signs formed by uniting the primary elements are called eomhina- Hon signals. A combination may consist entirely of a single primary signal several times repeated the number of repetitions conveying the mean- ing, e.g. Ill; or the combination may be formed by imiting several different primary signals, each used one or more times, e.g. 123, or 113, etc. A class of signals is the term used to desig- nate the number of elements used to make the signals, e.g. 131, 333, are signals of the third class; 12, 21 are signals of the second class, etc. ; a code of signals is any number of pre- arranged signals, each of which has a definite meaning to sender and receiver. If each letter is Iiomographic the class term is indicated by a certain and always the same number of sym- bols; chronosemic or time signals depend for their meanings upon the interval of time be- tween successive signals. For instance, a second ■ of time between two signals might represent '1,' and an interval of two seconds between the same signals '2,' etc. The definition and examples cited above are il- lustrated by the "United States Army and Navy Code Card" below. It is called the Myer system, after Brevet Brigadier-General Albert J. Myer, a . former chief signal officer of the United States army. It is a code of signals of two primary elements (1 and 2), the combination being of the first, second, third, or fourth class. Signal Coeps, D.n'ited States Abmy army code card — the myer system foe united states army and united states navy signaling (prescribed by g. o. no. 32, a. g. c, 1896). A 22 B 2112 C 121 D 222 E 12 F 2221 G 2211 H 122 I 1 J 1122 K. 2121 L 221 M N 1221 11 1 NUM 1111 3 1112 5 1122 7 1222 9 1221 Abbre b before h r are o p Q R S T U V w X Y z tioii.. CONTKNTIONAL SIGNALS Eud of a word 3 Eud of a seuteuce 33 End of a message 333 xx3 uumerals follow (or) numerals end sig3 signature follows Error 12 12 3 Acknowledgment, or " I understand " 22 22 3 Cease signaling 22 22 22 333 Wait a moment 1111 3 Repeat after (word) 121 121 3 22 3 (word) Repeat last word 121 121 33 Repeat last message 121 121 121 333 Move a little to right 211 211 3 Move a little to left 221 221 3 Signal faster 2212 3 The Myer system above is used by all the United States Army signal instruments except the electric telegraph, which employs the Morse code given below: a b c d e f g hi k 1 P 21 ..1212 ..1211 ...211 ...212 2 ...112 ..1222 ..1121 ..2122 ...111 ..2222 ..1112 ..2222 ..2221 ..2211 ..2111 ..2112 J qrstuv W X y z &c. "- --• --- "• *'■"» Visual Signal Apparatus. The Signal Corps of the United States Army employs two standard signal flags. 4 and 2 feet square respectively, with white ground and red centre, or the re- verse. They are attached to light jointed rods t the u you ur your w word wi with y yea and swung to the right, left, and centre when signaling. Any other flag, a piece of cloth, hand- kerchief, or other object attached to a stick may be used in the same way.