From this time he was in constant request in connexion with submarine telegraphy, and he became known also as an inventor.
Since the time of these early experiments, various other modes of detecting the existence of electric waves have been found out in addition to the spark-gap which he first employed, and the results of his observations, the earliest interest of which was simply that they afforded a confirmation of an abstruse mathematical theory, have been applied to the practical purposes of signalling over considerable distances (see Telegraphy, Wireless).
The city has a public library (1905), and is the seat of an Institute of Telegraphy (founded in 1874; chartered in 1900) and of Valparaiso University (1873; formerly known as the Valparaiso Normal Training School).
Land and Submarine Telegraphy will be considered in Part I., with a section on the commercial aspects.
Wireless Telegraphy is dealt with.
Part 1.-Land And Submarine Telegraphy Historical Sketch.
- Although the history of practical electric telegraphy does not date much further back than the middle of the, 9th century, the idea of using electricity for telegraphic purposes is much older.
The experience gained in the earlier days of ocean telegraphy, from the failure and abandonment of nearly 50 per cent.
The Belgian government endeavoured by reducing rates and increasing facilities to stimulate inland telegraphy in the hope of thereby increasing the profits of the department.
It had to extend the hours of business at all the offices; it had to extend the wires from railway stations lying outside of town populations to post offices in the centre of those populations and throughout their suburbs; it had also to extend the wires from towns into rural districts previously devoid of telegraphic communication; it had to effect a complete severance of commercial and domestic telegraphy from that of mere railway traffic, and in order to effect this severance it had to provide the railways with some 6000 m.
The monopoly conferred upon the Postmaster-General by the Telegraph Act 1869 was subsequently extended to telephony and wireless telegraphy, but it does not extend to submarine telegraphy.
Since the early days of international telegraphy, conferences of representatives of government telegraph departments and companies have been held from time to time (Paris 1865, Vienna 1868, Rome 1871 and 1878, St Petersburg 1875, London 1879, Berlin 1885,1885, Paris 1891, Buda Pesth 1896, London 1903).
His Life of his father (1898), his Address to London Chamber of Commerce on " Imperial Telegraphic Communication " (1902), Lecture to Royal United Service Institution on " Submarine Telegraphy " (1907), Lectures to Royal Naval War College (1910) and R.E.
Encouraged by this success, he even made the further suggestion that the remaining metallic portion of the circuit might perhaps some day be abolished and a system of wireless telegraphy established.'
Such an arrangement would distribute a 1 For a history of the discovery of the earth return, see Fahie, History of Electric Telegraphy to the Year 18 37, pp. 343-348.
Other experiments in inductive telegraphy were made by Preece, aided by the officials of the British Postal Telegraph Service, in Glamorganshire in 1887; at Loch Ness in Scotland in 1892; on Conway Sands in 1893; and at Frodsham, on the Dee, in 1894.
Or conductive telegraphy not necessitating a continuous cable.
A very ingenious call-bell arrangement was devised, capable of responding only to regularly reversed battery currents, but not 1 See Fahie, History of Wireless Telegraphy, p. 170; also 5th Report (1897) of the Royal Commission on Electrical Communication with Lightships and Lighthouses.
Rathenau of Berlin made many experiments in 1894 in which, by means of a conductive system of wireless telegraphy, he signalled through 3 m.
A very ingenious call-bell or annunciator for use with inductive or conductive systems of wireless telegraphy was invented and described in 1898 by S.
(Id., 27, p. 852.) In addition to the systems of wireless or space telegraphy depending upon conduction through earth or water, and the in ductive system based upon the power of a magnetic Eelson.
A very similar system of wireless telegraphy was patented by Professor A.
Many other more or less imperfect devices - such as those of Mahlon Loomis, put forward in 1872 and 1877, and Kitsee in 1895 - for wireless telegraphy were not within the region of practically realizable schemes.
Up to 1895 or 1896 the suggestions for wireless telegraphy which had been publicly announced or tried can thus be classified under three or four divisions, based respectively upon electrical conduction through the soil or sea, magnetic induction through space, combinations of the two foregoing, and lastly, electrostatic induction.
2 See Fahie, History of Wireless Telegraphy, p. 289; also an important letter by D.
Fleming's Electric Wave Telegraphy, by permission of Longmans, Green & Co.
See also The Principles of Electric Wave Telegraphy, by J.
Marconi's system of electric wave telegraphy consists therefore in setting up at the transmitting station the devices just described for sending out groups of damped electric waves of the above kind in long or short trains corresponding to the dash or dot signals of the Morse alphabet.
Marconi's successes and the demonstrations he had given of the thoroughly practical character of this system of electric wave telegraphy stimulated other inventors to enter the same field of labour, whilst theorists began to study carefully the nature of the physical operations involved.
We now consider the more recent appliances for electric wave telegraphy under the two divisions of transmitting and receiving apparatus.
In many cases additional condensers or inductance coils are inserted in various places so that the arrangement is somewhat disguised, but by far the larger part of the electric wave wireless telegraphy in 1907 was effected by transmitters having antennae either inductively or directly coupled to a closed condenser circuit containing a spark gap.
Fleming, The Principles of Electric Wave Telegraphy and Telephony, p. 416, 2nd ed.
When used as a receiver for wireless telegraphy Marconi inserted the oscillation coil of this detector in between the earth and a receiving antenna, and this produced one of the most sensitive receivers yet made for wireless telegraphy.
The problem of syntonic electric wave telegraphy is then to construct a transmitter and a receiver of such kind that the receiver will be affected by the waves emitted by the corresponding or syntonic transmitter, but not by waves of any other wavelength or by irregular electric impulses due to atmospheric electricity.
Slaby in Berlin shortly afterwards made a similar exhibition of syntonic electric wave telegraphy' O.
Lodge had previously described in 1897 a syntonic system of electric wave telegraphy, but it had not been publicly seen in operation prior to the exhibitions of Marconi and Slaby.'
Lodge was, however, fully aware that it was necessary for syntonic telegraphy to provide a radiator capable of emitting sustained trains of waves.
A method of syntonic telegraphy proposed by A.
The apparatus is exceedingly complicated and can only be understood by reference to very detailed diagrams. (See Principles of Electric Wave Telegraphy, by J.
At this stage it may be convenient to outline the progress of electric wave telegraphy since 1899.
Marconi's success in bridging the English Channel at Easter in 1899 with electric waves and establishing practical wireless telegraphy between ships and the shore by this means drew public attention to the value of the new means of communication.
Braun showed that oscillations suitable for the purposes of electric wave creation in wireless telegraphy could be set up in a circuit consisting of a Leyden jar or jars, a spark gap and an inductive circuit, and communicated to an antenna either by inductive or direct coupling (Brit.
Hence it will be seen that the difference between various forms of the so-called spark systems of wireless telegraphy is not very great.
In July and August 1899 the Marconi system of wireless telegraphy was tried for the first time during British naval manoeuvres, and the two cruisers, " Juno " and " Europa," were fitted with the new means of communication.
In 1904, during the RussoJapanese war, war news was transmitted for The Times by wireless telegraphy, the enormous importance of which in naval strategy was abundantly demonstrated.
A problem of great importance in connexion with electric wave telegraphy is that of limiting the radiation to certain directions.
Fleming, The Principles of Electric Wave Telegraphy (London, 1906), chap. vii.; also Cantor Lectures on Hertzian wave telegraphy, Lecture iv., Journ.
Braun also gave an interesting solution of the problem of directive telegraphy.'
Very valuable work in devising forms of antennae for directive radio-telegraphy has been done by MM.
15599 of 1903; also a lecture given in London, November 27, 1906, " On a Method of producing undamped Electrical Oscillations and their employment in Wireless Telegraphy," Electrician, 1906, 58, p. 166.