. The Bell System technical journal . —The tuned inductively coupled two-circuit radio transmitter adopted by Marconi in 1900. across space to any selected one or more of a number of different individualsin various localities each of whom is provided with a suitably arrangedreceiver. His radiator, modeled after Hertz, was a pair of capacityareas, or triangular shaped metal plates (one of them preferably grounded),separated by a spark gap and having interposed an inductance coil of a fewturns, for the purpose of tuning. This coil was not continuously adjustablebut was to be replaced by others f
. The Bell System technical journal . —The tuned inductively coupled two-circuit radio transmitter adopted by Marconi in 1900. across space to any selected one or more of a number of different individualsin various localities each of whom is provided with a suitably arrangedreceiver. His radiator, modeled after Hertz, was a pair of capacityareas, or triangular shaped metal plates (one of them preferably grounded),separated by a spark gap and having interposed an inductance coil of a fewturns, for the purpose of tuning. This coil was not continuously adjustablebut was to be replaced by others for changes of wave-length. The receiving 430 BELL SYSTEM TECHNICAL JOURNAL station was provided with a similar arrangement except that in place of thespark gap there was connected a Branly type coherer as a wave detector. While the particular forms of apparatus shown were never adopted inpractice, nevertheless Lodges tuning patent was upheld as valid in a legalcontest for priority later on (1911) and it was purchased by the Marconi. Fig. 6—Marconis tuned radio receiving antenna and circuit of 1900. Company as a result of the litigation.^ Lodge, in his autobiography PastYears, speaking with the usual modesty of the inventor rather than thescientist that he was, says, Real selective tuning became possible throughmy patent of 1897. . ^^ In Marconis first patent on wireless telegraphy, applied for in 1896(British patent No. 12,039, the very first patent in radio), there was noreference whatever to the matter of tuning. But his well-famed patentNo. 7777 of 1900^- was primarily concerned with this object and went muchahead of his jigger ideas of 1898. Here there were four tuned the sending station the spark gap circuit was inductively coupled to the HISTORY OF ELECTRICAL RESONANCE 431 transmitting aerial (an improvement credited to Ferdinand Braun ofGermany), and by means of a variable condenser in the former and a variableinductance in the latter these two circuits c
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