THETELEGRAPII. ELECTRIC 329 In the year 1848, there were but six thousand miles in operation ; so that in three years the amount has been nearly quintupled. Theelectric telegraph is now extendingin all directions,new lines are being constantly opened, and new proofs of its wonderful powers are recorded. The Dover Straithas been successfully crossed, and the continental nations are extending the system, as rapidly as their finances willpermit; the governments of Austria,Prussia, Bavaria,and Saxony, are adopting a general tariff, for messages transmittedthroughout their dominions. Russia is contemplating the connexion of its capital on the Baltic,with its ports on the Black Sea,while a stillampler conception presents itself, in which tire great lines of Eastern Europe may form but a link in the chain of general telegraphic communication. However premature, or sanguine, the expressionof these views may now appear, one fact is certain ; the electric telegraph is but in its infancy, and will yet become a powerful agent, in promoting the cause of civilization and the preservation of unity, peace and good-will throughout the world. NO.863.-“ On the Electric Telegraph, and the principal improve- ments in its Construction.” By FREDERICRRICH.4RD WINDOW, Assoc. Inst. C.E. THEnecessity of a means of communicating intelligence of events happening in any place, to another point at a distance, in a time less than that in which thedistance could be travelled, has been felt from the most remote ages ; and even among theearliest records there are instances of contrivauces for accomplishing this end, with more, or less certainty and success. To machines and instruments of this kind, has been given the name of “ telegraph,” (from rqhr, at a dis- tance, ypaqw, I write). The first and simplest form of telegraph that suggested itself, as the most readily available, was fire, which from its twofold accom- paniment of flameand smoke was an aptsignal by night, or by day. Watchfires, in ancient warfare, were always the signals from one troop to another, and to the present day,in Oriental countries, when a person of consequence travels, his advent is always signalled in advance, from hill to hill, by files kindled on the summits. That the use of telegraphs wasknown tothe Greeks, there is abundance of evidence to prove; it maybe instanced, that the Greeks believed the taking of Troy to have been telegraphed to Greece by Downloaded by [ UNIVERSITY OF BATH] on [12/09/16]. Copyright © ICE Publishing, all rights reserved. 330 TEI% ETJECTRIC TELEGRAPII. watchfires. The opening scene of the ‘‘ Agamemnon” of Bschylus introduces a warder, or watchman, whosays :-“ and llow I am watch- ing for the signalof the beacon, thefiery messenger bringing intelli- gence from Troy, and the news of its ca.pture !’, Polybius gives an account of telegraphic signals to be usedinwar (which hecalhrupaaat, because fire was used as the agent) ; and IEneas, the contemporary ofAristotle, proposed a system of telegraphs,by means of the isochronic escape of water from twovessels. All these methods were, however, necessarily very imperfect, as they involved the necessity of using only arbitrary preconcerted signals,or sentences, the number of which was very restricted, from the few combinations available, and by which it was only possible to communicate foreseen events. They do not seem to have been eve+ brought into general use : nor does it appear, that the nloderns ever possessed such a thing as a telegraph, beyondbeacon fires, until 1663, when theNarquis of Worcester announced his discovery of ‘(a method by which intelli- gence can be conveyed as far as eye can discover black from white, without noise made, or notice taker], andalso by night, though dark as pitch be blaclr.” At the end of the seventeenth century, M. Amontons invented a new method of telegraphic correspondence, by means of an imperfect semaphore,established on a chain of stations,from one place to another. In 1763 it was proposed, by Mr. Edgeworth, to correspond by means of a windmill, the position of the arms, and thesails being slipped on, or of, to constitute the signals. But it was not until tile French &volution in 1793, that the telegraphwas ever syst,enratically applied touseful purposes, the method employed being the invention of M. Chappe, direring but little, however, fiwn that of M. Amontor~s. The correspondence was transmittedfrom the “ Comiti. deSolut Public,” at the Louvre, to Lisle, the station of the French army at that period. A description of the machine was taken to Frwkfbrt, where two models of it were made, and presented by Mr. Playfair to the Duke of Pork. A description of it appeared in the “ Englislk Ileview,” of June 1796, and shortly afterwards the Chvernment set up a chain of stations from the Admiralty to the sea-coast. Various improvements in telegraphs were introduced, in quick successior?, by scientificmen, amongst whom thename of Sir Home Popham is distinguished, and snbsequently’that of General Pasley, wlm in 1822, invented the c‘ Universal Telegraph,” which has been in general use ever since, till the rapid stride of science overcoming intervening obstacles, it, in its turn, was superseded by the wonders of galvanic electricity. During the greater part of the last century, the ppscibility of Downloaded by [ UNIVERSITY OF BATH] on [12/09/16]. Copyright © ICE Publishing, all rights reserved. THE ELECTltIC TELEGIBAI’II. 33 l transmittingintelligence by meansof electricity, was a favourite schemewith philosophers; and many experiments were made, at various times, in furtherance of this idea, of which the following are a few of the most interesting and worthy of notice. In 1733, Dn Fay made some experiments in France, in order to ascertain the distance to which the electric current could be sent ; and electricshocks were senf through upwards of‘ fourmiles of copper wire. In 1746, Winkler, at Leipzic, passed electric currents through a long wire, part of the river Pleiss being included in the circuit. In 1748, Dr. Watson suspended two miles of wire upon wooden posts, at Shooter’s Hill, and completing the circuit by tht earth, sent electrical currents through it. This fact of using, so early as 1748, the earth as the return circuit, is worthy of note ; for in the earlier inventions of the present century a separate wire was reserved for thispurpose, and it was notuntil 1838, that Mr. Cookeagain suggested, that the earth might be effectuallyemployed.’ In Arthur Young’s ‘<Travels in France,” published in 1787, is thefollowing paragraph : “ An ingenious mecllanic hasmade a reinarkable discovery. You write two, orthree words upon paper, 11e takes it with him into a room, and turns a nlachine enciosed in a ’ In describing a pair of electro-magnetic signal telegraphs, for the Aix-la- Chapelle lhilway, ProfessorWheatstone stated,-“ That alarge extent of earth, or a portion of a river, could be made to conlplete an electric circuit, was long since established with respect to electricity of high tension, by the extensiveexperiments of Dr. Watson,in 1746, andothers; and the same thing was proved with regard to voltaic electricity, by the iiidcpendcnt cxperi- lnents of Ennan, Basse, and Aldini, made in 180% Erman’s experiments were performed in the river Havel, near Potsdam; those of Basse in the river Weser, and the environs of Hand ; and Aldini’s researches were prosecuted on the shore near Calais. Professor Steinheil also employed the earth as a means of complchig thc circuit, in the clectro-magnetic telegraph which he estdblishcd at I\lunich in 1632. “ A pair of Professor Wheatstone’s telegraplx were established at Berlin in the begiuning of 1612 : the line of con~nlunicationwas a siogle wire, carried througll the air up011 wooden posts, and plates of metal attached to the ends of the wire we-x buried in the ground. In the same year hc formed a communi- cation betwcen King’s College and the Shot-tower on the opposite side of the river : the comnlunicating wire was laid along the parapets of Somerset-house and Waterloo-bridge, and thence to the top of the tower, where one of the telegraphs was placed ; the wire then descended, and a plate of zinc attached to its extremity wasplunged into the n~udof the river; asimilar plate was attached to the extremity at the north side, and was immersed in the water. The circnit was thus completed by the entire breadth of the Thames, and the telegrapils acted as we11 as if the circuit uas eotirely metallic.”-Vide Minutes of Proceedings Inst. C.E., 1643, vol. xi. p. ~~~.-EI)~ToR. Downloaded by [ UNIVERSITY OF BATH] on [12/09/16]. Copyright © ICE Publishing, all rights reserved. 332 TlIE TLECTRIC TELECIRAPII. cylindrical case, at the top of which is anelectrometer, and fine pith balls. A wire conwcts with a similar electrometer, in a distant apartment, and his wife, by re~narltillg the correrpondi~gmotions of the balls, writes down the words they indicate, from wllich it appears he has formed an alphabet of motions. As the length of the wire makes no difference of effect, a correspondence might be carried on at any distance.” Thushere is a &earaccount of a singlewire electric telegraph, so early as 17&7. In 1787, a wire twenty-seven miles in length was extended, by Betancourt, between Madrid and Aranjuez, by which shochs from a Leyden jar were transmitted, and pith balls were repelled. Early in the present century, Siimmering invented a telegral)h, consisting of thirty-five wires,--twenty-five forthe letters of the alphabet and ten for thenumerals,-by which water was decomposed as the signal. Thisform was, however,too expensive inits con- struction, to become of any commercial utility. Shortly afterwards, Ronalds produced a scheme of two rotating dials, moved by clockwork, having the letters painted on them, and one of them only appearing at a time, at a hole in a shade, placed in front of the dial; as the letter which it was intended EO indicate, appeared, two pith balls were repelled, by means of electricity.