|  
               Historical Problems 
              Tesla described his wireless power transmission method 
                by three characteristics: 1) the reduction or elimination of electromagnetic 
                radiations, 2) that it operated through the earth, and 3) that 
                the mechanism of transmission is an electric current - as contrasted 
                with radiations. Modern analysts, on the other hand, model Tesla's 
                transmission system on present day broadcast radio technology. 
                This model assumes an antenna propagating electromagnetic waves 
                into the air where these radiations either will not or will, depending 
                on the presuppositions of the writer, bring about the effects 
                claimed by the inventor. 
              Anachronistic interpretation - applying the assumptions 
                of today's electrical theories to Tesla's original turn of the 
                century researches - is only half the problem of understanding 
                the inventor's wireless method. The situation is further complicated 
                by the similar sounding descriptions Tesla gave to his earlier 
                and later transmission techniques. 
              In his early work Tesla attempted electronic transmission 
                by modifying the atmosphere. This is the case in his patent entitled 
                Method of Intensifying and Utilizing Effects Transmitted Through 
                Natural Media, #685,953, applied for in June 1899. In this patent 
                he proposes a very powerful signal generator to ionize atmospheric 
                gases and, by that, create a conductive path between the transmitter 
                and receiver through which a current could be sent. Later, when 
                Tesla disclosed what he described as through-the-earth (or water) 
                transmission with essentially the same type of apparatus and operating 
                at ELF frequencies, it has been assumed by modern authorities 
                that Tesla was mistaken about his method of propagation and was 
                really witnessing earth-ionosphere cavity resonance at Schuman 
                frequencies [1,2]. 
              Tesla, though, 
                was more than an engineer of conventional methods. He was an electrical 
                researcher who investigated fundamental issues of the science. 
                It will be shown that the three characteristics of Tesla's wireless 
                transmission system describe an electrostatic wireless method 
                that used the earth as a conductor and transmitted displacement 
                currents. At moderate power levels the system could  
             | 
             
               be used for communication. At greater levels, power could be sent by wireless. 
              Non-Hertzian Transmission 
              During 1899 - 1900 Tesla set up a laboratory in Colorado 
                Springs to investigate wireless signal transmission. It was during 
                this period he discovered that a properly configured receiver 
                could detect waves, initiated by lightning strikes, propagating 
                through the earth. When he incorporated this discovery into a 
                patent he differentiated the earlier technology dealing with "effects 
                transmitted through natural media" from the new form of signaling 
                that involved the transmission of energy. This is seen in his 
                patent Art of Transmitting Electrical Energy Through the Natural 
                Mediums, #787,412, applied for 11 months after the previous patent, 
                in May 1900. 
              A great deal of detail about the apparatus for generating 
                and receiving electrical signals (tuned resonant circuits that 
                were recognized in 1943 by the Supreme Court as the basis of commercial 
                radio designs) is given in the patent but it assumes, 
                or more likely, avoids revealing, the physics behind the mode 
                of propagation. Tesla does point toward his novel transmission 
                technique when he notes in the patent that the "globe may 
                ... behave ... as a conductor of limited size;"[3] and that 
                low frequency oscillations keep the "radiation of energy 
                into space in the form of hertzian or electromagnetic waves... 
                very small."[4] These two claims, alone, indicate a technology 
                different from today's. 
              The illustration (see Figure 
                1 on the next page)for the 
                patent is of a transmitter consisting of an elevated capacitance, 
                a coil, a signal generator, and a single electrode in the earth. 
                The receiver is pictured as having a mechanism to oscillate at 
                the same period as the transmitter, a capacitor, a detector, and 
                two earthed plates. 
              To understand Tesla's wireless 
                transmission system it is necessary to look at his technical writings 
                on the physics behind his engineering. One of his lectures on 
                evacuated tube illumination provides a good example. 
             |