Wireless Transmission of Energy - Dream or Possibility Page 32

language and published in a book in 1978. In the United States a translation of the commentary of the Serbo-Croatian edition of the Diary of 1976 appeared, with the explanation that this contains some significant details in which, it was alleged, answers about some interesting data are concealed, which an attempt had been made to withhold from English readers.

If Tesla did not publish everything in the notes from Colorado Springs, it still remains for us to hope that some new and interesting data will be found in the notes from Long Island. In going through these notes we had considerable difficulty understanding what Tesla was studying. This time he was not as systematic and exhaustive as when writing the Colorado diary, but there is plenty of material. The notes from Long Island cover a period of several years, but they are most numerous in the interval from 1901 to 1903. Considerable effort is needed to arrange and decipher the papers. Much of what Tesla did on Long Island remained unpublished and, in a certain sense, unfinished. Besides the notes in the Nikola Tesla Museum, numerous drawings of various devices connected with the world telegraph system were also found, which were not accepted as patents. To tell the truth, we do not even know whether they were considered in the United States Patent Office or elsewhere. Among these drawings the interesting one is that which relates to a large tower with a terminal capacitance, which is charged by Tesla’s high-frequency transformer (see Fig. 4). According to some American scientists, the capacitance at the top of the tower periodically discharges, creating impulses of currents of low frequency which are capable of transmitting energy with little attenuation over a considerable distance. Such a system is not a conventional radio transmitter at all, and it is not easy to understand what would happen if one were working with voltages of the order of 100 million volts, which Tesla constantly demanded!

The notes from Long Island show that Tesla took great pains to understand the phenomenon of the propagation of energy in the Earth–antenna system. He made calculations for frequencies of 4, 6, 40, and several hundred hertz. From the notes it is clearly seen that he wavered in the choice of frequency, for the reason that low frequencies are better from the point of view of attenuation (less attenuation at lower frequencies was later confirmed), while high frequencies are easier to radiate with better efficiency. It seems that he did not have a definitive answer as to which frequencies these would be, since through the calculations he carried out at various times the same calculations keep appearing with different initial data. Low frequencies seemed unsuitable to him also because of the difficulties in forming a resonant transmitting system. He made a calculation of the coils for operation at 6 Hz and concluded that extremely large quantities of wire would be needed in order, with a tower capacitance of 10,000 pF, to obtain a resonant system. We tried to finish Tesla’s calculation of such a system and concluded that he would have needed about 800 kg of copper wire, and the coils, placed one after another, would have formed a row 56 km long.

On 2 June 1901, in the notes from Long Island, Tesla devoted 13 pages to questions connected with the “Transmission of Electrical Energy through the Earth by Open Synchronous Circuits.” A photograph of the first page of these