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tube, inasmuch as the electric Auid it would be sufficient to connect the passes through the metal included by wires at each end with the gas or the coating, in exactly the same man- water pipes which, being conductors, ner as water or gas passes through the would equally convey the fluid to the pipes which conduct it ; with this dif- earth; and in this case, every teleference, however, that the electric graphic despatch which flies to Edinfluid moves along the wire more freely, burgh along the wires which border in an almost infinite proportion, than the railways, would fly back, rushing does either water or gas in the tubes to the gas-pipes which illuminate which conduct them.
Edinburgh--from them through the If, then, a wire, coated with a non- crust of the earth to the gas-pipes conducting substance, capable of re- which illuminate London, and from sisting the vicissitudes of weather, them home to the batteries in the celwere extended between any two dis. lars at Lothbury. tant points, one end of it being at- The atmosphere, when dry, is a good tached to one of the extremities of non-conductor ; but this quality is im. a galvanic battery, a stream of elec. paired when it is moist. In ordinary tricity would pass along the wire- weather, however, the air being a suf. provided the other end of the wire were ficiently good non-conductor, a meconnected by a conductor with the other tallic wire will, without any other cxtremity of the buttery.
insulating envelope except the air To fulfil this last condition, it was itself, conduct the stream of electricity usual, when the electric telegraphs to the necessary distances. It is true were first erected, to have a second that a coated wire, such as we have wire extended from the distant point already described, would be subject to back to the battery in which the elec- less waste of the electric fluid en route; tricity was generated. But it was but it is more economical to provide afterwards discovered that the EARTH batteries sufficiently powerful to bear
was the best and by far the this waste, than to cover such extencheapest and most convenient conduc. sive lengths of wire with cotton, or tor which could be used for this re- any other envelope. turning stream of electricity. Instead, The manner in which the conducttherefore, of a second wire, the ex- ing wires are carried from station to tremity of the first, at the distant station is well known. Every railway point to which the current is sent, is traveller is familiar with the lines of attached to a large metallic plate, wire extended along the side of the measuring five or six square feet, railways, which, when numerous, have which is buried in the earth. A simi. been not unaptly compared to the lar plate, connected with the other series of lines on which the notes of extremity of the battery, at the station music are written, and which are the from which the current is transmitted, metallic wires on which invisible mesis likewise buried in the earth, and it sages are flying continually with a is found that the returning current speed that surpasses imagination. finds its way back through the earth These wires, in the case of the Engfrom the one buried plate to the other lish telegraphs, are galvanised so as to buried plate.
resist oxydation, and are of sufficient Of all the miracles of science, surely thickness to bear the tension to which this is the most marvellous. A stream they are submitted. They are susof electric fluid has its source in the pended on posts, erected at intervals cellars of the Central Electric Tele. of sixty yards, being at the rate of graph Office, Lothbury, London. It thirty to a milé. These posts, thereHows under the streets of the great fore, supply incidentally a convenient metropolis, and, passing along a zig- means by which a passenger can ascerzag series of railways, reaches Edin. tain the speed of the train in which he burgh, where it dips into the earth, travels. If he count the number of and diffuses itself upon the buried telegraph posts which pass his eye in plate. From that it takes flight two minutes, that number will express through the crust of the earth, and in miles per hour the speed of the finds its own way back to the cellars at train. Lothbury !!
To each of these poles are attached Instead of burying plates of metal, as many tubes or rollers of porcelain
or glass as there are wires to be sup. In France, on the other hand, and ported. Each wire passes through a in the United States, the wires, even tube, or is supported on a roller ; and in the cities and towns, are conducted the material of the tubes or rollers on rollers at an elevation, as on other being among the most perfect of the parts of the lines. In Paris, for ex. class of non-conducting substances, ample, the telegraphic wires proceedthe escape of the electricity at the ing from the several railway stations points of contact is impeded.
are carried round the external bouleNotwithstanding these precautions, vards and along the quays, the rollers a considerable escape of electricity being attached either to posts, or to still takes place in wet weather. The the walls of houses or buildings, and coat of moisture which collects on are thus carried to the central station the wire, the tube or roller, and at the Ministry of the Interior. the post being a conductor, carries In Europe, the telegraphic wires inaway more or less of the fluid. Con- variably follow the course of railways, sequently, more powerful batteries are and this circumstance has led some to necessary to give effect to the tele- conclude that, but for the railways the graph in wet than in dry weather. electric telegraph would be an unpro
In England, and on the Continent, fitable project. the material used for the supports of This, however, is a mistake. In the the wires is porcelain. In the United United States, where a much greater States it is glass, which is a more per- extent of electric telegraph has been fect insulator. In England the sup- erected and brought into operation ports are tubes-on the Continent and than in Europe, the wires do not follow in America they are rollers.
the course of the railways. They are In some cases, as for example in the conducted, generally, along the sides streets of London, it is found incon- of the common coach-roads, and some. venient to carry the wires elevated on times even through tracts of country posts, as here described. In such cases where no roads have been made. other methods are adopted.
It contended in Europe that the The wires proceeding from the cen- wires would not be safe, unless placed tral telegraph station in London are within the railway fences. The reply wrapped with cotton thread, and coat- to this is, that they are found to be ed with a mixture of tar, resin, and safe in the United States, where there grease. This coating forms a perfect is a much less efficient police, even in insulator. Nine of these wires are the neighbourhood of towns, and in then packed in an half-inch leaden most places no police at all. It may in-pipe, and four or five such pipes be observed, that the same apprehenare packed in an iron pipe about sions of the destructive propensities of three inches in diameter. These the people have been advanced upon iron pipes are then laid under the foot first proposing most of the great impavements, along the es of the provements which have signalised the streets, and are thus conducted to the present age. Thus, when railways terminal stations of the various rail- were projected, it was objected that ways, where they are united to the mischievous individuals would be conlines of wire supported on posts along tinually tearing up the rails, and the sides of the railways, already de- throwing obstructions on the road, scribed.
which would render travelling so dan. Provisions, called testing-posts, are gerous, that the system would become mnade at intervals of a quarter of a impracticable. mile along the streets, by which any When gas-lighting was proposed, it failure or accidental irregularity in the was objected that evil-disposed persons buried wires can be ascertained, and would be constantly cutting or breakthe place of such defect always known ing the pipes, and thus throwing whole within a quarter of a mile.
towns into darkness. In Prussia, and one or two other Experience, nevertheless, has proved continental states, the system of sub- these apprehensions groundless; and terranean conducting-wires is exclu- certainly the result of the operations sively adopted, not only in cities, but on the electric telegraph in the United generally along the entire telegraphic States goes to establish the total inulines.
tility of confining the course of the wires to railways. Those who have gards the strong galvanised iron wires been practically conversant with the which in the open air run parallel system, both in Europe and in America, to our arterial railways, if in wet weago further, and even maintain that the ther, in spite of the many ingenious telegraph is subject to less inconve- precautions taken, the rain should nience, and that accidental defects are form a continuous stream between the more easily made good, and that an ef- several wires and the ground, the ficient superintendence is more easily electric fluid, escaping from the wires, insured on common roads, according is conducted by the water till it finds to the American system, than on rail. earth, the best of all conductors; and, ways according to the European sys- therefore, instead of the intelligence tem. Our limits, however, preclude going on, say to Edinburgh, it follows us from entering into all the details of the axiom of electricity by selecting this question.
the shortest road, and thus completing Nothing in the history of the in- its circuit through the earth, it refluence of the arts on social progress turns to London. Sometimes, instead presents a more curious subject of re. of going to earth, it Aies back to the flection than do these systems of me- office in London, along another wire, tallic wire passing under our feet as we to which, by means of a continuous walk the streets, and beside us as we line of water, or of entanglement of the traverse the railways.
two wires, it has managed to escape ;
in which case, the messages on the two “In our metropolis," observes a lively wires wrangling with each other, the contemporary, " there is scarcely a street communication is stopped. which does not appear to take pride in exposing, as often as possible, to the public " It is commonly asserted and believed, view, a series of pipes of all sizes, in which
that many birds are killed by merely perchfire of various companies, pure water of va
ing upon the iron wires of the clectric telerious companies, and unmentionable mixtures,
graph; but at any time they can do so with common to all, pass cheek by jowl with in
perfect impunity. If, indeed, a bird could finitely less trouble than the motley hu
put one of his feet on the wire, and with the man currents flow above them. But among
other manage to reach the earth, he would all the subterranean pipes laid bare be
then, no doubt, be severely galvanised. That fore us, there is certainly no one which
the railway company's men often pick up has more curious contents than the three
under the wires of the electric telegraph, inch iron pipe of the electric telegraph
partridges, and other birds, which have evicompany; and yet of all the multitudes who
dently been just killed_indeed some are walk the streets, how few of them ever care found with their heads cut off—is quite true; to reflect what a singular contrast exists be- but these deaths and decapitations have tween the slow pace at which they themselves
proceeded, not from the electricity, but from are proceeding, and the rate at which, be
the birds, probably during twilight or a fog, neath their feet, forty-five electric wires are
having at full speed flown against the wires, transmitting in all directions, and to a va
which, of course, cut their heads off, just riety of distances, intelligence of every pos- as an iron bar would cut off the head of sible description !
any man, or alderman on horseback, who at “ How singular is it to reflect, that within
a full gallop was to run foul of it. the narrow space of the three-inch iron pipe
"In windy weather, the electric wires form which encases them, notice of a murder is
an Æolian harp, which occasionally emits flying to the London papers, passing news
most unearthly music. “I say, Jack !' said from India going into the country ; along an engine-driver to his stoker, who like another wire an officer is applying for his himself was listening for the first time to regimentals, while others are conducting this querulous sort of poise, proceeding from to and fro the price of stocks,'' news of the
the newly-erected wires along his line, 'I Pope,' a speech from Paris of the collapsed
say, Jack! ain't they a-giving it to them poet," &c. &c. &c.
“When the posts and wires of the electric In case, from the abrasion of the telegraph between Northampton and Petercotton that surrounds the numerous
borough were being erected, an honest far
mer, who for many minutes bad been very copper wires within the pipe, any of
attentively watching the operation, inquired them come into contact with each
of the chief superintendent to what use it other, the intelligence which each is
was to be applied ? On being told that by its conveying is suddenly confounded; in means he would in a few minutes receive at which case other wires must instantly Willingborough a list of the Mark-lane be substituted. Indeed, even as re. prices in London, he evidently incredulously
asked how that was to be done ?-and on its signals sufficiently varied for telegrabeing explained to him that the intelligence phic purposes. would be sent down to him letter by letter,
1. To explain the deflection of a he exclaimed, · But you don't mean to say
magnetic needle, let us suppose a copthat besides letters it will bring down par
per wire extended over the magnetic cels too ' "*
needle of a common compass, so that
the direction of the wire shall be paBut to return to the admirable
rallel to the needle, without touching means whereby those extraordinary it. In this state of things, the needle effects are produced, and to answer will remain undisturbed; but if we the worthy farmer's inquiry somewhat send an electric current along the more intelligibly, let us now see how
wire, which may be done by connect. the electric current which flows along ing the ends of the wire with those of the conducting-wires is made to speak,
a galvanic battery, the needle will in. to make dumb signs, or to write the
stantly throw itself at right angles to despatch when it arrives at its desti
the wire, and will remain in that ponation.
sition so long as the galvanic current There are a great variety of pro- is maintained ; but if that current be perties of the electric current which
discontinued, by withdrawing either supply means of accomplishing this. end of the wire from the trough, the
If the electric current can be made needle will instantly resume its posito affect any object in such a manner tion of rest. as to cause such object to produce any It is found, also, that the north pole effect sensible to the eye, the ear, or of the needle will turn, in this case, in the touch, such effect may be used as
one direction or in the other, according a sign; and if this effect be capable of
to the direction given to the galvanic being buried, each distinct variety of
current. If this current flow in one which it is susceptible may be adopted direction, the north pole will throw as a distinct sign. Such signs may itself to the east, and the south to the then be taken as signifying the letters west ; if it flow in the contrary direcof the alphabet, the digits composing tion, the north pole will be thrown to numbers, or such single words as are
the west, and the south pole to the of most frequent occurrence.
east. The rapidity and precision of the
2. To explain the sudden convercommunication will depend on the rate sion of iron into a magnet, and the at which such signs can be produced sudden destruction of the magnetic in succession, and on the certainty and virtue thus imparted, let us suppose a accuracy with which their appearance
copper wire to be coiled round a piece at the place of destination will follow
of soft iron spirally, so that the sucthe action of the producing cause at cessive coils shall not touch each other the station from which the despatch is nor touch the iron, which may be done transmitted.
by coating the wire with silk, or any These preliminaries being under
resinous or non-conducting substance. stood, it remains to show what effects
This being done, let us suppose that of the electric current are available
an electric current is transmitted for this purpose.
through the wire, so that it shall flow These effects are:
spirally round the rod of soft iron, ' I. The power of the electric current which may be effected by placing, as to deflect a magnetic needle from its before, the ends of the wire in a galposition of rest.
vanic trough. If steel filings, a needle, II. The power of the current to or any light piece of iron, be brought impart temporary magnetism to soft near the rod or iron thus circumiron.
stanced, they will instantly be attracted III.— The power of the current to by it, showing that it has acquired the decompose certain chemical solutions. magnetic virtue ; and this effect will
We shall now briefly show the man- continue to be produced so long as the ner in which these properties supply galvanic current shall be maintained
"Stokers and Pukers." By the Author of “ Bubbles from the Brunnens of Nassau," pp. 125-7.
along the spiral wire; but the instant independently of that which is prothat the end of the wire is withdrawn duced by a single movement to the from the galvanic trough, the mag- left. In like manner, two successive netic virtue deserts the iron, and it movements to the right will supply will no longer attract.
another signal; and thus we have four 3. If a sheet of paper, moistened independent signals. with a chemical solution which is ca- But from these four signals we may pable of decomposition by the galvanic immediately produce four more, as we corrent, be laid upon a metallic plate, may combine one movement to the which is in connexion with one end of right with two to the left, and vice the battery, and the point of a wire in versa ; and one to the left with two to connexion with the other end of the the right, and vice versa: and thus battery, be brought into contact with would have eight independent the paper, a decomposition will take signals. place, and a change of colour will be We may carry this method further, produced upon the paper under the and so arrange the system that three point of the wire, just as if a dot were successive movements to the right and made upon it by a pen charged with three successive movements to the left coloured ink. If the wire be moved shall have independent significations ; upon the paper, a coloured line will be and these again may be combined with traced ; and if the point of the wire each of the eight signals already exbe moved as a pen or pencil might be, plained ; and, in short, we may carry any characters may be thus written on this system to an extent which shall be the paper as they would be with a pen limited only by the inconvenience of charged with coloured ink, similarly the delay which would take place in moved. If in this case the current be making the repetitions necessary for discontinued during any intervals, the such signals. wire, though still in contact with the Subject to this delay, however, it is paper, will leave no trace or dot. clear that with a single machine we
To render intelligible the means may easily obtain expressions for all whereby these three poperties have the letters of the alphabet and the ten been made instrumental to the trans- numerals. mission of intelligence to a distance- But to obviate the inconvenience
We have explained how a magnetic which would attend multiplied repetineedle over which an electric current tions in the movements of a single passes will be deflected to the right needle, we may provide two indepen. or to the left, according to the direc- dent wires, which shall act upon two tion given to the current. Now, it is independent needles. always easy to give the current the Each of these needles primarily will one direction or the other, or to sus. afford two independent signals hy their pend it altogether, by merely changing movements right and left. These four the ends of the galvanic trough with signals may be combined in pairs, so which the wires are connected, or by as to afford four other signals produbreaking the contact altogether. cible by a single movement. Thus,
A person, therefore, in London, simultaneously with the right hand having command over the end of a movement of one needle we may prowire which extends to Edinburgh, and duce the right-hand movement of the is there connected with a magnetic other. In the same way we may simulneedle, in the manner already de- taneously produce the left-hand movescribed, can deflect that needle to the ment of both, or the right-hand of right or to the left at will.
either combined with the left-hand Thus a single wire and a magnetic movement of the other, which would needle are capable of making at least give eight independent signals, the protwo signals.
duction of each of which would occupy But signals, whatever be the form no more time than that of a single of the telegraph used, may be multi- movement. We may then adapt the plied by repetition and combination. signals by double movement of each Thus the operator at London may needle, which, combined with each make the needle at Edinburgh move other, and with the single movements, twice successively to the left, and this will afford another set of combinations; may be conventionally settled as a sign, and by combining these systems, we