Signor Marconi’s Magic Box: The invention that sparked the radio revolution. Gavin Weightman. Читать онлайн. Newlib. NEWLIB.NET

Автор: Gavin Weightman
Издательство: HarperCollins
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Жанр произведения: Биографии и Мемуары
Год издания: 0
isbn: 9780007402250
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as the young man unloaded brass knobs, coils and tubes and set them out on the table. Mullis was sent to fetch a Morse key, some batteries and wire. When he returned, Preece looked at his gold pocket-watch, remarked that it was past midday, and told Mullis to take Marconi to the Post Office refreshment bar and to ‘see he gets a good dinner on my account’. They were to be back by 2 p.m.

      When they returned from lunch, Preece watched as Marconi pressed the Morse key and rang a bell in his receiving apparatus. This greatly intrigued the Post Office chief, who had apparently never witnessed the use of electronic waves in this way. At the end of the day Marconi was invited back, and he and Preece made some adjustments to the equipment with the help of the Post Office workshop. By the end of July Preece felt confident enough to arrange for Marconi to demonstrate his wireless to senior officials of the Post Office. What impressed everyone most was the fact that the signals could be sent three hundred yards, then nearly a mile, and then even further, with that mysterious ability to go straight through stone walls.

      Preece had been booked long before to speak on wireless telegraphy at Toynbee Hall in December, and had intended to give an account of his own work sending messages across the sea on the west coast of Scotland. But he now wondered if his system, which required huge lengths of parallel wires to cover quite short distances, was less promising than Marconi’s. If it did the same job, Marconi’s would certainly be quicker and cheaper to install. Preece decided to take the opportunity of the Toynbee Hall lecture to introduce his protégé to a wider audience, which is how the two of them came to travel to Whitechapel that December evening. It had been as recently as the summer of 1894 that Marconi first conceived the idea of the use of Hertzian waves for telegraphy, in just over two years he was being fêted by the Chief Electrical Engineer of the mighty British Post Office, and by the spring of 1897 he was being pursued by more than one investor interested in his patents.

       5

       Dancing on the Ether

      In the springtime migrant birds moving north to their nesting grounds, yellow wagtails and peregrine falcons, cross the Bristol Channel between the northern coasts of the English counties of Devon and Dorset and the south coast of Glamorgan in Wales. They skim over Steepholm and Flatholm Islands, which lie in the middle of the Channel, and rise up over Lavernock Point, a low cliff facing south from the Welsh coast. A colourful host of pink and white flowers attracts the butterflies which dance in the coastal breezes. There are relics of old gun batteries here, which guarded the wide estuary of the Severn River. When William Preece was experimenting with his method of wireless telegraphy in 1892 he chose the three-mile span between Lavernock Point and Flatholm Island, and found that he could establish a link between the two. He had much less success when he tried to create a link to Steepholm Island, which lies more than five miles from Lavernock.

      Flatholm to Lavernock seemed to Preece the ideal testing ground for Marconi’s novel wireless system, and in May 1897 he arranged for an experiment which would demonstrate the potential of his protégé’s equipment. Although Preece had publicly expressed great faith in Marconi’s invention, he was not at all sure that these magic boxes could send and receive signals over any great distance. By nature he was a risk-taker, but over his long career some embarrassing experiences had taught him caution. There was the time in 1877 when the young Alexander Graham Bell, not quite thirty years old, was invited to demonstrate his new invention, the telephone, to Queen Victoria at her summer home, Osborne House on the Isle of Wight.

      Beginning at 9.30 p.m., Bell, with the help of Preece, had created a link between the main house and a cottage in the grounds so that the Queen could speak to two aristocrats familiar to her. She listened also to a rendition of the song ‘Coming Through the Rye’ sung by an American journalist called Kate Field, who had been hired to write promotional articles about the telephone. The Queen was most impressed as calls and performances came in from Cowes, Southampton and London. The grand finale was to be ‘God Save the Queen’, played by a brass band in Southampton. This had been William Preece’s patriotic idea. But as Her Majesty waited for the burst of music, the line from Southampton went dead. By the time it was fixed the musicians had packed away their tubas and trumpets and gone home. Not wanting to disappoint everybody after such a successful day, Preece himself put his mouth to the microphone and hummed the national anthem down the line, putting as much oompah into his rendition as he could. After listening for a few moments, Queen Victoria is said to have remarked: ‘It is the national anthem, but it is not well played.’

      Preece was aware that he might be in for another embarrassing experience in the cause of technological advance when he asked Marconi to send a signal from Flatholm to Lavernock. There was an element of rivalry in the experiment, for Preece regarded himself as an old hand at this business of telegraphing without wires, and wanted a demonstration of the merits of his own system alongside that of the young Italian. Despite his apparent enthusiasm for Marconi’s invention, Preece appears to have hedged his bets, and was not convinced that it would have more than a very limited value to the Post Office. It was still a novelty, and might turn out to be no more than that.

      While Marconi assembled his transmitter on Flatholm Island and a receiving station on the cliff at Lavernock, Preece had already had lengths of wire put in place, running in parallel on either side of the Bristol Channel. When an electric charge was sent through one of these wires it would emit waves which were picked up by the other, and a charge was made to ‘jump’ across the space between, just like the ‘crossed lines’ that had caused problems with telephones and telegraphs in the City. By turning the current on and off, it was possible to send the dots and dashes of Morse code. Preece had used this ‘induction’ system as a temporary link between the Isle of Skye on the west coast of Scotland and the mainland when the telegraph cable snapped, and knew it worked across the Bristol Channel.

      Preece presumably did not imagine he was about to witness anything of historic importance as he waited in the buffeting breezes for Marconi’s signals to come through to Lavernock Point. He was, after all, the head of a British government department which dominated cable telegraphy worldwide, and which could hardly be threatened by a young amateur scientist and his makeshift apparatus. Preece had invited a German Professor, Adolphus Slaby of the Technical High School at Charlottenburg, near Berlin, to witness the demonstration. Slaby had read about Marconi’s ability to send signals over quite long distances, although he himself had had much less success.

      Lavernock Point is about sixty feet above sea level. Marconi had an aerial put up which rose a further sixty feet in the air, and was topped with a zinc cylinder connected to a receiver which had been set up to record signals in Morse code on a tickertape. Another wire went from the receiver down the cliff to the seashore. The transmitter, firing off a crackle of sparks, was three miles away on Flatholm Island. For two tense days nothing came through on the Lavernock receiver. In desperation, Marconi had the receiver taken down to the beach below the cliff, to see if that made any difference. Almost instantly it began to work.

      While William Preece did not really grasp the significance of the occasion, an amazed Professor Slaby certainly did. ‘It will be for me an ineffaceable recollection,’ he said later. ‘Five of us stood round the apparatus in a wooden shed as a shelter from the gale, with eyes and ears directed towards the instruments with an attention which was almost painful, and waited for the hoisting of a flag which was the signal that all was ready. Instantaneously we heard the first tic tac, tic tac, and saw the Morse instrument print the signals which came to us silently and invisibly from the island rock, whose contour was scarcely visible to the naked eye – came to us dancing on that unknown and mysterious agent the ether!’ He wrote up an account of what he had witnessed for the American Century Magazine, which was published in April 1898.

      In January, 1897, when the news of Marconi’s