Ordine del giorno





By Radio Officer Urbano CAVINA.

MICHAEL FARADAY discovered electro-magnetic induction between two entirely separate circuits.

Year 1837

The first patent for an electric telegraph taken out by Cooke and Wheatstone (London) and by Morse (U.S.A.)

Year 1838

K.A. Steinheil (Munich) discovered the use of the earth return and suggested that remaining metallic portion of the circuit might be dispensed with entirely, and a system of wireless telegraphy established.

Year 1842

S.F.B. Morse made wireless experiments by electric conduction trough a water across Washington Canal and across wide rivers. Joseph Henry noticed that a single electric spark about one inch long thrown into a circuit of wire in an upper room could magnetise steel needles included parallel circuit of wire placed in a cellar underground thirty feet below with two floors intervening. He was one of many observers prior to Hertz who had noticed curious effects due to electric sparks produced at a distance, which were commonly ascribed to ordinary electromagnetic induction.

Year 1843

James Bowman Lindsay, of Dundee, suggested that if it were possible to provide stations of not more than twenty miles apart all the way across the Atlantic, there would be no need to lay any cable.

Year 1845

Lindsay began making experiments in 1845 across the river Tay, his method being to transmit messages by means of electricity or magnetism trough and across the water without submerged wires, the water being utilised as the conducting medium.

Year 1849

J.W. Wilkins revived the same suggestion for wireless telegraphy, Dr. O'Shaughnessy (afterwards Sir William O'Shaughnessy Brooke) succeded in passing intelligible signals without any metallic conduction across the River Hoogly, 4200 ft. wide, in India, but he found the cost of power prohibitive.

Year 1859

Bowman Lindsay gave a demostration of his conduction system to the British Association Meeting, at which Michael Faraday and Sir William Thompson (Lord Kelvin) were both present. William H. Preece (afterwards Sir William) was deputed by the Electric Telegraph Company to report on Lindsay's System.

Year 1862

John heyworth patented a method of conveying electric signals without the invention of any continuous artificial conductor. Cromwell Varley tried this method, but found it a failure.

Year 1867

James Clerk Maxwell read a paper before the Royal Society, in which he laid down the theory of electro-magnetism, which he developed more fully in 1873, in his great treatise on electricity and magnetism. He predicted the existence of the electric waves that are now used in wireless telegraphy.

Year 1870

Von Bezold discovered that oscillations set up by a condenser discharge in a conductor give rise to interference phenomena.

Year 1872

Henry Highton made various experiments across the River Thames with Morse's method.

Year 1879

David E. Huges discovered the phenomena on which depends the action of coherers, which many years late were used in early electric-wave signalling. He found that a tube of metallic filings was sensitive to electric sparks made in its vicinity, and he was able to obtain such effects on a tube connected to a battery and a telephone at a distance of five hundreds yards.

Year 1880

John Trowbridge, of Haward, systematically studied the problem of propagation of electric current trough "earth" either soil or water, and he found that signalling might be carried on over considerable distances by electric conduction trough the earth or water between places not metallically connected.

Year 1882

Graham Bell experimented with Trowbridge's method on the Potomac River, when signals were detected at a distance of 1,5 miles. Sir William H. Preece made an experiment, using Morse's method to connect the isle of Wight with the mainland across the Solent on two occasions during the failure of the submarine cable in Solent.

Year 1883

Willoughby Smith, in a paper before the Institution of Civil Enginners, London, suggested that electric induction might be employed for railway signalling. Heinrich Rudolph Hertz became privat docent at Kiel, where he began studies in Maxwell's electro-magnetic theory. G.F. Fitzgerald suggested a method of producing electromagnetic waves in space by the discharge of a condenser.

Year 1885

Thomas A. Edison, with the assistance of Messrs. Gilliland, Phelps, and W. Smith, worked out a system of communication between railway stations and moving trains by means of induction and without the use of conducting wires. Sit. W.H. Preece made experiments at Newcastle-on.Tyne which showed that in two completely insulated circuits of square form, each side being 440 yards, placed a quarter mile apart, telephonic speech was conveyed from one to the other by induction.

 Year 1886

A. E. Dolbear of Tuft's College, Boston, patented a plan for establishing wireless communication by means of two insulated elevated plates, but there is no evidence that the method proposed by him did, or could, effect the transmission of signals between stations separated by any distance.

Year 1887

Heinrich Rudolph Hertz discovered the progressive propagation of electro-magnetic action trough space, and was able to measure the length and velocity of electro-magnetic waves and to show that in transverse nature of their vibration and their susceptibility to refraction and polarisation they are in complete accordance with the waves of light and heat. Hertz employed as detector of the electric wave a simple nearly closed circuit of wire, called "Hertz Resonator" but it is subsequently discovered that the metallic microphone of Huges was a far more sensitive detector. A.W. Heaviside established communication by telephoníc speech between the surface of the erarth and the subterranean galleries of the Broomhill Collieriers, 350 ft deep, by laying above and below the ground two complete metallic circuits, each about 2,25 miles in length and parallel to each other.

Year 1889

Elihu Thompson suggested that electric waves were particulary suitable for the trasmission of signals trough fogs and metal objects.

Year 1891

John Trowbridge suggested that by means of magnetic induction between two separate and completely insulated circuits communication could be effected between distances.

Year 1892

Edouard Branly devised an appliance for detecting electro-magnetic waves, which was known as a "coherer". He discovered that these waves had the power of affecting the electric conductivity of materials when in state of a powder. Sir. W.H. Preece adopted a method which united both conduction and induction as the means of affecting one circuit by the current in another. In this was he established communication between two points on the Bristol Channel and at Lochness in Scotland. C. A. Stevenson of Northern Lighthouse Board, Edinburgh, advocated the use of an inductive system for communication between the mainland and isolated lighthouses.

Year 1894

E. Rathenau of Berlin experimented with a conductive system of wireless telegraphy and signalled trough three miles of water.

Year 1895

Mr. G. Marconi's investigations led him to the conclusion that Hertzian waves could be used for telegraphing without wires, and he made important experiments at his father's home in Italy. Willoughby Smith established communications by conduction with the lighthouse on the Fastnet.

Year 1896

In February Mr. Marconi come to england. His first experiments in this country were conducted at Westbourne Park. On June 2nd Mr. Marconi lodged his application for the first British Patent for Wireless Telegraphy, N° 12039 of 1896. In July of that year he was introduced to Sir William H. Preece, the Chief Electrical Enginner of the Post Office at whose request Mr. Marconi conducted experiments before the officials of the Post Office, first over a distance of about 100 yards and afterwards between the General Post Office and the Savings Bank Department in Queen Victoria Street. Shortly aftewards a series of trials were conducted by Mr. Marconi before Post Office officials and naval and military officers on Salisbury Plain, when communication was successfully established over a distance of 1,75 miles. On December 11th 1896, Sir William H. Preece delivered a lecture at Toynbee Hall on "Telegraphy without Wires" Mr. Marconi was present at this lecture and conducted experiments.

 Year 1897

In March 1897, Mr. Marconi gave a demostration on Salisbury Plain before the representatives of various Government Departments, communicating being established over a distance of 4 miles. In May further trials were made across the Bristol Channel between Lavernock and Flatholm, a distance of over 3 miles: and the 13th of that month communications was established between Lavernock Point and Brean Down , at a distance of about 8 miles. Professor Slaby, a German scientist, was present at these trials. In July Mr. Marconi was called to Italy by the Italian Minister of Marine and gave demonstration of his invention in the Admirality buildings at Rome, and before King Humbert at the Royal Palace of the Quirinale. Between July 10th and 18th trials were made at Spezia at the request of Italian Government and on the 17th and 18th communication was successfully made and mantained between the Arsenal of San Bartolomeo at Spezia and the italian cruiser San Martin at sea, at distances up to 16 km. On July 20th 1897, the Wireless Telegraph and Signal Company, Limited, was incorporated, with a capital of £ 100.000 to acquire Mr. Marconi's patents in all countries except Italy and her dependancies. On August 27th, 1897, a lecture was given by Professor Slaby at the Sailor's Home, Potsdam, on Wireless Telegraphy, before the Emperor and Empress of Germany and the King of Spain. In September and October further experiments were conducyed by Mr. Marconi on Salisbury Plain for Post Office officials. Experiments were also carried out by officials of the Post Office at Dover. Receiving apparatus was erected by a Post Office official at Bath, and signals were received from Salisbury, 34 miles distant. In November the first Marconi Station was erected at the Needles, Alum Bay, Isle of Wight. Experiments were conducted between that Station and Madeira House, South Cliff, Bournemouth, where Mr. Marconi was residing at the time, a distance of 14,5 miles. In December tests were made between the Station of Alum Bay and a steamer, the height of the mast being about 60 ft., and readable signals were obtained up to a distance of 18 miles, Captain Kennedy, R.E., being present.

 Year 1898

In May, 1898, experiments were carried out by Mr. Marconi between St. Thomas's Hospital and the House of Commons. In the same month experiments were carried out at the request of Lloyd's between Ballycastle and Rathlin Island, a distance of 7,5 miles. On June 3rd Lord Kelvin visited the Needles Station and sent from there, to his friend Sir Georges Stokes, the first paid Marconigram. On July 20th and 22nd the events of the Kingstown Regatta in Dublin were reported by wireless telegraphy for the Dublin  Daily Express from the steamer Flying Huntress, equipped with the Marconi system. On August 3rd wireless telegraphic communication was established between the Royal yacht Osborne and Ladywood Cottage, Osborne, in order that Queen Victoria might communicate with the Prince of Wales, then suffering from the results of an accident to his knee. Constant and uninterrupted communications was mantained during the sixteen days the system was in use. In September the installation at Madeira House, Bournemouth, was removed to Poole harbour, Dorset. Under arrangement with the Trinity House officials the utility and value of wireless telegraphy as means of communication between lightships and the shore was demonstrated by the installation in December,1898, of the East Goodwin Lightship and the South Foreland Lighthouse. The intervening distance was 12 miles. Communications was first established on Christmas Eve, and continuously mantained for more than a year

 Year 1899

During a gale in January 1899 a heavy sea struck the East Goodwin Lightship, carrying part of her bulwarks away. The mishap was reported by wireless telegraphy to Trinity House. On March 2nd Mr. Marconi read a paper on Wireless Telegraphy at the Institution of Electrical Engineers. On March 3rd the S.S. R.F. Matthews ran into the East Goodwin Lightship. The accident was reported by wireless telegraphy to the South Foreland Lighthouse and lifeboats were promptly sent to the assistance of the lightship. On March 27th communication was established across the Straits of Dover between the Chalet d'Artois, Wimereux near Boulogne and the South Foreland Lighthouse. During the naval manoeuvres in July three British warships, the flagship Alexandra and the cruisers Europa and Juno were equipped with Marconi apparatus and messages were correctly exchanged between these vessels at distance up to 74 nautical miles (about 85 land miles). In September Marconi Stations were installed at Chelmsford and Dovercourt. During the meetings of British Association at Dover and the Association Francaise pour l'Avancement de Science at Boulogne, in August, communication between the two societies was mantained by means of Marconi apparatus installed at Dover Town Hall and at Wimereux. The international yacht races between the Shamrock and the Columbia which took place in September and October 1899 were reported by wireless telegraphy for the New York Herald. After the conclusion of the races, series of trials were made at the request of the U.S.A. naval authorities between the cruiser New York and the battleship Massachusetts, signals being exchanged between the vessels at distances up to 36 miles. On the return journey from America Mr. Marconi fitted the S.S. St. Paul with his apparatus and on November 15th established communication with the Needles Station when 36 miles distant. Reports of the progress of the war in South Africa were telegraphed to the vessel and were published in a leaflet entitled "The Transatlantic Times" printed on board the St. Paul. In October 1899 the War Office adopted the Marconi apparatus for use in the field in South Africa and on November 2nd six of the company electricians left for South Africa with six sets of Marconi apparatus. The apparatus proved of considerable service to the army and to the naval squadron in Delagoa Bay to which several of the sets were subsequently transferred.




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