Tesla: The Life and Times of an Electric Messiah by Nigel Cawthorne Page A

from the end of a streetcar line that stopped just short of Knob Hill. Current was passed though a 50-kilowatt Westinghouse transformer, stepping the voltage up to 20,000 or 40,000 volts.
    In the centre of the room, was a secondary coil comprising hundreds of turns of finer wire. One end was connected to a round terminal inside the laboratory or the copper ball on top of the mast. The other end was earthed. The apparatus was completed by a bank of capacitors that could be discharged by a motorized brake-wheel, while other large coils moved in and out of the magnetic field.
    Tesla began experimenting with wireless telephones, reporting to Astor: ‘There is nothing novel about telephoning without wires to a distance of 5 or 6 miles [8 or 9 km], since this has been done often before … In this connection, I have obtained two patents.’
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    Taking the Pulse of the Planet
    Tesla also experimented sending electrical signals through the earth. Then on 4 July 1899 a huge electrical storm arrived. He recorded ‘no less than 10,000 to 12,000 discharges being witnessed inside of 2 hours. The flashing was almost continuous and, even later in the night, when the storm had abated, some 15 to 20 discharges per minute were witnessed. Some of the discharges were of a wonderful brilliancy and showed often ten or twice as many branches.’
    He could track these discharges with his sensitive detecting equipment and he noted that they registered, periodically, even when the storm had moved out of sight. They seemed to start and stop every half an hour. Tesla concluded that the lightning strikes had created electromagnetic waves in the earth’s crust which, reflected back on themselves, set up stationary waves. These moved past the receiver as the storm receded.
    While Marconi could send radio waves across the English Channel, Tesla believed that by harnessing these waves ‘not only would it be practicable to send telegraphic messages to any distance without wires, but also to impress upon the entire globe the faint modulations of the human voice, far more still, to transmit power, in unlimited amounts, to any terrestrial distance without loss’.
    â€˜With these stupendous possibilities in sight,’ wrote Tesla, ‘I attacked vigorously the development of my magnifying transmitter, now, however, not so much with the original intention of producing one of great power, as with the object of learning how to construct the best one.’
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    Mars on the Horizon
    Improving his instruments, Tesla found he could detect electrical disturbances 1,100 miles (1,770 km) away. The detector was a ‘coherer’ – a glass tube filled with iron fillings – connected via a capacitor to the ground. This was placed within the secondary coil of the magnifying transmitter. When a signal was applied to the electrode, the iron fillings would align, allowing current in a secondary circuit to pass though it.
    Tesla connected a telephone receiver across the coherer which would beep each time a signal was detected. Alone in the laboratory one night, he was surprised to hear regular beeps – first one, then two, then three.
    â€˜My first observations positively terrified me,’ said Tesla, ‘as there was present in them something mysterious, not to say supernatural … I felt as though I were present at the birth of a new knowledge or the revelation of a greater truth.’
    He quickly discounted that a signal with ‘such a clear suggestion of number and order’ could have come from disturbances in the Sun, the aurora borealis or currents in the Earth. They could not be entirely accidental and the thought flashed through his mind that they might be under intelligent control. He could not decipher them, but over the next year ‘the feeling was constantly growing on me that I have been the first to hear the greeting of one planet to another’.
    At Christmas 1900, the local Red Cross