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A History of Wireless Telegraphy (2nd edition, revised), J. J. Fahie, 1901, pages 48-55:
G. E. DERING--1853.
The problem of wireless telegraphy was taken up about this time by Mr George Dering of Lockleys, Herts, who was, like his old Rugby tutor, Henry Highton, a prolific inventor of electrical and telegraphic appliances, patents for which he took out on eleven separate occasions between 1850 and 1858, and many of which came into practical use in the early Fifties. His needle telegraph, patented December 27, 1850, was in use in the Bank of England early in 1852, connecting the governor's room with the offices of the chief accountant, chief cashier, secretary, engineer, and other officials. About the same time it was partially used on the Great Northern Railway, and exclusively so on the first Dover-Calais cable (1851), where it did excellent service, working direct between London and Paris for a long time (including the busy period of the Crimean war), until supplanted by the Morse recording instrument.
In the same specification of 1850, Dering patented three methods of carrying off atmospheric electricity from the linewires (a) "Two roughened or grooved metallic surfaces separated by fine linen, one of which is included in the line-wire circuit, and the other is in connection with the earth." This was afterwards (in 1854) repatented by (Sir) William Siemens, and is now known as Siemens' Serrated-Plate Lightning-Guard. (b) "The attraction or repulsion occurring between dissimilarly or similarly electrified bodies respectively. Thus metal balls may be suspended from the line-wire by wires, which on separating under the influence of the lightning-discharge make contact with plates connected with the earth; or the separation may simply break connection between the line-wire and the instrument." (c) "Introducing a strip of metallic leaf into the circuit, this being fused by the passage of the atmospheric electricity." This very effective method has also been reintroduced in later years, and always as a novelty, by various telegraph engineers.
Dering's telegraphic appliances made a goodly show at the Great Exhibition of 1851, side by side with Henley's colossal magnets, and received "honourable mention." They were again on view at the Paris International Exhibition of 1855, where they were awarded a medal for general excellence.
Dering's proposals for a transmarine telegraph are contained in his patent specification of August 15, 1853, from which we condense the following account:--
"The present invention is applicable to submarine telegraphs, and also to the means of communication by under-ground or over-ground wires. Heretofore, in constructing electric telegraphs where the whole circuit has been made of metal, and also where the conducting property of the earth has been employed as a part of the circuit, it has been usual, and it has been considered absolutely necessary, to cause the wires to be thoroughly insulated, the consequence of which has been that the expense of laying down electric circuits has been very great, particularly where the same have crossed the sea or other waters, where not only have the wires been insulated, but in order to protect the insulating matter from injury further great cost has been caused by the use of wire rope, or other means of protection.
"Now, I have discovered that a metallic circuit formed of wires, either wholly uninsulated or partially so, may be employed for an electric telegraph, provided that the two parts of the circuit are at such a distance apart that the electric current will not all pass direct from one wire to the other by the water or earth, but that a portion will follow the wire to the distant end.
"To carry out my invention, I cause two uninsulated or partially insulated wires to be placed in the water or in the earth, at a distance apart proportionate to the total length of the circuit, the said wires being insulated where they approach one another to communicate with the instruments, in order to prevent the current passing through the diminished water or earth space between them. The batteries (or other suitable source of electricity) employed are to be constructed in the proportion of their parts in conformity with the well-known laws which regulate the transmission of electric currents through multiple circuits--that is, they should possess the properties generally understood by the term quantity in a considerably greater degree than is usual for telegraphing through insulated wires, which may be effected (in the case of galvanic batteries) by using plates of larger dimensions, or by other alterations in the exciting liquids or plates. The proper distance at which to place the conductors from one another is also determined by the same laws, all of which will be readily understood by persons conversant with the principles of electrical science. In practice I find that from one-twentieth to one-tenth the length of the line-wires is a sufficient distance.
"Another method of carrying out my invention consists in establishing circuits composed in part of the uninsulated or partially insulated conductors, and in part of the conducting property of the sea, across which the communication is to be made, or of the earth or the moisture contained therein in the case of land telegraphs. For this purpose the connections are effected at such a distance in a lateral direction that a sufficient portion of the current will pass across the water or earth space and enter the corresponding wire connection at the other extremity. The connecting wires at the termini must be effectually insulated as in the first method.
"A third method consists in placing in the sea or earth two wires of dissimilar metal having the quality of generating electricity by the action of the water or moisture with which they are in contact. If at one extremity the wires be attached respectively to the two ends of the coil of an electro-magnet or other telegraphic apparatus, it will be found that the instrument is acted on by the current generated by the wires. If now at the other extremity the wires be connected, a portion of the current will complete its circuit through this connection, instead of all passing through the electro-magnet, where consequently the effect will be diminished; and if means be adopted to indicate this greater or less power, signals may be indicated at one end by making and breaking contact at the other. If desirable, currents derived from galvanic batteries, or other source, may be employed as auxiliary to those generated in the outstretched wires.
"In the different means of communication which I have described, if strong conductors are required, as in submarine lines, wire rope may be employed, either alone or attached to chains for greater strength and protection, or the conducting wires may be attached to hempen ropes, or enveloped within them. The metal composing the wires may be iron or copper or any other suitable kind, and it may be coated with varnish, by which means the amount of exposed surface will be diminished, and the metal preserved from corrosion.
"I will now suppose the case of a line to be carried out upon the principle which I have described, say from Holyhead to Dublin, a distance of about sixty miles. It would be necessary, first, to select two points on each coast from three to six miles apart, and to connect these points on each coast by insulated wires. Next, the two northern points are to be connected by a submerged uninsulated conductor, and the two southern points by a similar conductor, unless the water be employed as a substitute in the manner before described. Thus an oblong parallelogram of continuous conductors is formed, having for its longer sides the uninsulated conductors, and for its shorter sides the insulated wires along the coasts. If now these latter wires be cut at any parts, and instruments and batteries be connected in circuit, signals may be transmitted by any of the means ordinarily employed with insulated wires.
"Or, to take the case of a longer line, say from England to America, I should select two points, as the Land's End in Cornwall and the Giant's Causeway in Ireland or some suitable place on the west coast of Scotland, and corresponding points on the American shore. Next, I should unite the two points in each country by insulated wires, and, finally, submerge two uninsulated conductors across the Atlantic, or one if the water be employed to complete the circuit. Then by introducing, as before, suitable telegraphic instruments and batteries the communication will be established.
"From the foregoing description it will be seen that the cost of laying down electric telegraphs, whether submarine or otherwise, is, by this invention of employing distance between the conductors as a means of insulation, reduced to little more than the mere cost of the wires, together with that of an insulated wire at each end; while the numerous difficulties which attend the insulation of long lengths of wire are avoided, as also the chances of the communication being interrupted by accidents to the insulation"
At the time of this patent, and for many years after, the difficulties just referred to were only too real. Many of the cables laid between 1850 and 1860 failed after a longer or shorter period, and chiefly through defective insulation. Hence, no doubt, the persistency with which telegraph engineers in the Fifties sought in telegraphy without insulation, and telegraphy without wires, other and more economical ways of solving the great problem of transmarine communication.
Dering's experiments were performed across the river Mimram at Lockleys, Herts, with bare parallel wires of No. 8 galvanised iron, laid at a distance apart of about 30 feet, or one-tenth of the space to be traversed. With a small battery power of only two or three Smee cells the signals were easily readable.
At one of these performances on August 12, 1853, the chairman and directors of the Electric Telegraph Company of Ireland (one of several mushroom companies then started) were present, and so impressed were they with the results obtained that they there and then decided to adopt the system for their intended line between Portpatrick and Donaghadee. This is a fact not generally known in the history of early submarine telegraph enterprises; and what is still less known, for there is no record of it, is that the project was actually attempted. In a recent letter, Mr Dering, who I am glad to say is still with us, has given me some interesting details of the attempt which I now publish, feeling sure that they will be new to the reader.
On September 23, 1853, the necessary wire in bundles was shipped to Belfast, which, "for the sake of ultra economy," consisted of single No. 1 galvanised iron instead of twisted strand wire as Dering had recommended. On examination the wire proved to be so unreliable, with numerous weak and brittle places--chiefly at the factory welds--that Bering urged delay and the substitution of stranded wire. "Had we been wise," writes Mr Dering, "we should have abandoned the attempt with this unsuitable material, but it was resolved to go on and risk it--testing the wire as far as might be beforehand and removing the weak parts. I, however, addressed a formal letter to the board of directors in London, stating that the wire was so unreliable I must decline all responsibility as to the laying it down, but that I would do the best I could."
After carefully testing the various lengths, removing all weak parts and bad welds as far as they could be discovered, and jointing and tarring the whole into one long length, the wire was paid into the hold of the Albert. On November 21 a start was made, a shore-end wire was laid from Milisle, carried out to sea, and buoyed. Next morning the Albert, 33 piloted by H.M.S. Asp (Lieut. Aldridge), picked up the buoyed end, joined it to the wire on board, and paid out successfully for about 3½ miles, when the wire broke at a factory weld, and the ship returned to Donaghadee "in a gale of wind."
The next few days were occupied in some alterations to the paying-out machinery, found by experience to be desirable, and on the 26th another start was made. The wire on board was joined to the buoyed end at 4 miles from shore, and paying-out proceeded successfully as far as mid-channel (about 12 miles) when the wire broke, again at a factory weld, and the end was lost in 82 fathoms of water. The ship then returned to the buoy and tried to underrun the wire, but it soon broke again, and for the moment further attempts were abandoned.
Previous to this two unsuccessful attempts had already been made to connect Great Britain and Ireland by cables made on the lines of the Dover-Calais cable of 1851--one, undertaken by Messrs Newall & Co., between Holyhead and Howth, June 1, 1852, which failed three days after; and the other, a heavy six-wired cable, undertaken by the same firm, between Portpatrick and Donaghadee, October 9, 1852, which broke in a gale after sixteen miles had been paid out.
In June 1854 Messrs Newall recovered the whole of this sixteen miles of cable, and completed the laying to Portpatrick, thus rendering another attempt at a bare wire cable unnecessary, if, indeed, it was still thought desirable.
Mr Dering's faith in the soundness of his views is still unshaken, for he goes on to say: "Instead of a single wire, as in 1853, I should now advocate the use of a bare strand of wires for each of the conductors. And I must add, considering the craving there is at present for Wireless Telegraphs, that it seems to me not altogether improbable that the less ambitious but (for, at all events, long distances) far more feasible plan of using bare wires will yet have its innings." And who, in these days of electrical marvels, will dare to say him nay? I, for my part, will not, for I have seen more unlikely things come to pass. The dream of to-day, "idle and ridiculous" as it may seem, has been so often realised on the morrow, that the cautious historian of science must not look for finality in any of its applications. 34
33 With Dr Hamel on board, the famous Russian scientist of Alpine celebrity, as the representative of his Government.
34 For recent applications of the bare-wire principle, see Meihuish, infra.
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