Home >> Encyclopedia Americana, Volume 26 >> Tao Te King to Telegraphy >> Telegraphy_P1


torches, semaphore, letter, station, arms, system, wall and feet

Page: 1 2 3 4 5 6 7 8 9 10 | Next

TELEGRAPHY. The word telegraph is derived from the Greek, tele, °afar off," and graph, °to write.* In the modern practice of telegraphy, however, the term has a wider meaning and is used to signify any means by which intelligence is transmitted to a dis tance by signs or sounds. In this sense the word would also include the transmission of speech electrically to a distance, but inas much as that highly important art possesses its own appellation (telephony) such a use of the word is unnecessary.

From remotest times methods of com municating intelligence to a distance have been employed for purposes of war and The Greeks were perhaps the first to adopt systematic methods of telegraphing, and a description of a telegraph system that was em ployed 300 B.C. is to be found in the writings of the Greek General Polybius.

Polybins The operation of this system was as follows: At each station there were two walls about seven feet in length and about six feet in height, separated by a space of three feet. At night one or more torches, as desired, but not exceeding five in all, were placed on top of the walls, and certain combinations of the torches rep resented the letters of the Greek alphabet. A tablet showing the combinations of torches for the various letters was provided at each station. For instance, two torches on the right-hand wall and three on the left wall would represent the letter H. •Five torches on the right wall and four on the left, Y, and so on. When it was desired to signal a sta tion, two torches were set on a wall, which signal was answered by a similar arrange ment of torches at the other station. The operator then proceeded to spell out his message by placing the torches in the re quired combinations, one letter at a time. The tablet mentioned was divided into five ver tical and five horizontal rows of squares, each letter of the alphabet being allotted a certain square, beginning at the upper left-hand corner with A, and running horizontally across the tablet. Any letter could thus be found by giving the number of vertical and horizontal rows at the intersection of which was the square allotted to that letter. For instance, the letter Y would he at the inter section of the fourth horizontal and the fifth vertical rows. The code thus formed, in a more or less modified form, is in use to-day by the military departments of various coun tries as a means of telegraphing maps of a locality.

Fire and Smoke The use of fires by night and smoke by day has long been practised by even the most uncivilized races, as a means of communicating intelligence to a distance. In numerous places in this coun

try there still remain evidences of thiS prac tice by the aborigines, in the shape of mounds on hill tops and other points of advantage, on which the accumulated ashes of beacon fires of bygone years may be found beneath the roots of trees of gigantic size. In the country be tween Chillicothe and Columbus, Ohio, for in stance, may be traced over 20 such mounds, so related to one another that if all the trees were removed fire signals might be transmitted from one end of the valley to the other in a few minutes. To this day the Indians of North America practise this method of signaling the approach of enemies in their territory; and up to within a comparatively short time beacon fires were the most favored methods of sig naling the approach of an enemy in Great Britain and other parts of Europe.

Semaphore It was not until the end of the 18th century that any comprehensive plan of signaling was employed in Europe or in this country. The plan then introduced was that known as the Chappe semaphore system of signaling. This semaphore resembled the sema phore so common on all railways to-day, con sisting of an upright post, on the top of which movable arms or blades are pivoted, but in the Chappe semaphore the arms were arranged quite differently from those of the ordinary railroad device. Thus the crossarm on the top of the post was 14 feet in length, and at each end of this arm a shorter arm was pivoted at right angles to the longer arm. By a sys tem of ropes and pulleys these arms could be nianipulated by the operator and placed in many different positions, certain positions of the arms representing given letters of the al phabet. Hence by appropriately placing the arms, the manipulator could spell out words and messages which an operator at a distant station could read and, if necessary, retransmit to another station further on. These sema phores were placed on substantial stone towers at distances apart ranging from six to 10 miles; and their use spread rapidly throughout Europe. In France, Germany and Russia especially the system was widely used. For example, a string of 220 semaphore towers, extending from the Prussian frontier to Petrograd, via Warsaw, a distance of over 1,200 miles, and employing over 1,300 operators was erected at great ex pense. In PrusSia also a line of semaphore stations from Berlin to Treves, via Potsdam, Magdeburg, Cologne and Coblenz, was estab lished in 1832, at a cost of 170,000 dialers. In France there was a semaphore line from Paris to Toulon, 475 miles apart, and requiring 120 stations.

Page: 1 2 3 4 5 6 7 8 9 10 | Next