Nikola Tesla Books
the Nikola Tesla Museum in Belgrade. According to Tesla's caption these diagrams are “Illustrating various ways of using highfrequency alternator in the first experiment at Grand Street Laboratory 1891 - 1892". It seems that Tesla made these to prove his priority in a patent suit(35). Only some of these diagrams have been published in(4, 6, 13), so that this is an important document throwing new light on an exceptionally fertile but relatively little known period of Tesla's work. It is, for example, clear from these diagrams that he introduced an HF transformer in the open antenna circuit. Circuits like that in Fig. 3c - 4 are to be found later in two patents filed in 1897(13, 14) on his apparatus and system for wireless transmission of power (these patents refer to Tesla's disruptive dis charge oscillator as an alternative to the high-frequency alternator).
In February 1893 Tesla held a third lecture on high-frequency currents before the Franklin Institute in Philadelphia(6), and repeated it in March before the National Electric Light Association in St. Louis. The most significant part of this lecture is that which refers to a system for “transmitting intelligence or perhaps power, to any distance through the earth or environing medium”. What Tesla described here is often taken to be the foundation of radio engineering, since it embodies principles ideas of fundamental importance, viz.: the principle of adjusting for resonance to get maximum sensitivity and selective reception, inductive link between the driver and the tank circuit, an antenna, circuit in which the antenna appears as a capacitive load(71). He also correctly noted the importance of the choice of the HF frequency and the advantages of a continuous carrier for transmitting signals over great distances(12).
Between 1893 and 1898 Tesla applied for and was granted seven American patents on his HF oscillator as a whole(25), one on his HF transformer(26), and eight on various types of electric circuit controller(27). In a later article(28) Tesla reviews his work on HF oscillators and reports that over a period of eight years from 1891 on he made no less than fifty types of oscillator powered either by DC or low-frequency AC.
Along with his work on the improvement of his HF oscillators Tesla was continuously exploring applications of the currents they produced. His work on the improvement of X-ray generating apparatus is well known - he reported it in a series of articles in 1896 and 1897(7) and in a lecture to the New York Academy of Sciences(17). In a lecture before the American Electro-Therapeutic Association in Buffalo September 1898(18) he described applications of the HF oscillator for therapeutic and other purposes. The same year he took out his famous patent “Method of and apparatus for controlling mechanism of moving vessels or vehicles”(59), which embodies the basic principles of telemechanics a field which only began to develop several decades after Tesla's invention.
On 2nd September 1897 Tesla filed patent application No. 650343, subsequently granted* as patent No. 645576 of 20th March 1900(13) and patent No. 649621 of 15th May 1900(14). Unlike other radio experimenters of the time who worked either with damped oscillations at very high frequencies(43), Tesla investigated undamped oscillations in the low HF range. While others principally developed Hertz's apparatus with a spark-gap in the tank circuit (Lodge, Righi, Marconi, and others) and improved the receiver by
* The second of the two patents by which Tesla protected his apparatus for wireless power transmission, known as the “system of four tuned circuits”, is particularly important in the history of radio. It was a subject of a long law suit between the Marconi Wireless Telegraph Company of America and the United States of America alleged to had used wireless devices that infringed on Marconi's patent No. 763772 of 28th June 1904. After 27 years the U.S. Supreme Court in 1943 invalidated the fundamental radio patent of Marconi as containing nothing which was not already contained in patents granted to Lodge, Tesla and Stone(65).
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Tesla: “Experiments with alternate currents of very high frequency and their application to methods of artificial illumination”, a lecture delivered before the AIEE, May 20, 1891, L-15.
Tesla: “On light and other high frequency phenomena”, a lecture delivered before the Franklin Ins. Philadelphia, Febr. 1893, L-107.
Tesla: “On Roentgen rays”, El. Rev. March 11, 1896, A-27, A-32
“On reflected Roentgen rays, El. Rev. April 1, 1896, A-34
“On Roentgen radiations”, El. Rev. April 8, 1896, A-39
“Roentgen ray investigations”, El. Rev. April 22, 1896, A-43
“An interesting feature of X-ray radiations”, El. Rev. July 8, 1896, A-49
“Roentgen rays or streams”, El. Rev. August 12, 1896, A-51
“On the Roentgen stream”, El. Rev. Dec. 1, 1896, A-56
“On the hurtful actions of Lenard and Roentgen tubes”, El. Rev. May 5, 1897, A-62
“On the source of Roentgen rays and the practical construction and safe operation of Lenard tubes”, El. Rev. Aug. 11, 1897, A-69.
Eccles, W. H. WIRELESS, Thornton Butterworth Ltd, London, 1933.
Tesla N. “System of transmission of electrical energy”, U.S. Patent 645 576, March 20, 1900, Appl. Sept. 2, 1897.
Tesla: “Apparatus for transmission of electrical energy”, U.S. Patent 649 621, May 15, 1900, Appl. Sept. 2, 1897, P-293.
Tesla N. “The stream of Lenard and Roentgen and novel apparatus for their production”. Lecture before New York Academy of Science, Apr. 6, 1897 (Nikola Tesla Museum, Belgrade)
Tesla: “High frequency oscillators for electro-therapeutic and other purpose”, a lecture delivered before the American Electro-Therapeutic Association, Buffalo, Sept. 13, 1898 L-156.
Tesla: “Means for generating electric currents”, U.S. Patent 514 168, Febr. 6, 1894, Appl. Aug. 2, 1893, P-225.
“Method of regulating apparatus for producing currents of high frequency”, U.S. Patent 568 178, Sep. 22, 1896. Appl. June 20, 1896, P-228.
“Apparatus for producing electric currents of high frequency and potential”, U.S. Patent 568 179, Sep. 22, 1896, Appl. April 22, 1896, P-233.
“Method and aparatus for producing currents of high frequency”, U.S. Patent 568 179, Sep. 22, 1896, Appl. July 6, 1896, P-237.
“Apparatus for producing electrical currents of high frequency", U.S. Patent, 568 180, Sep. 22, 1896, Appl. July 9, 1896, P-241.
“Apparatus for producing electric currents of high frequency", U.S. Patent, 577 670, Feb. 23, 1897, Appl. Sep. 3, 1896, P-245.
“Apparatus for producing currents of high frequency", U.S. Patent, 583 953, June 8, 1897, Appl. Oct. 19, 1896, P-249.
Tesla: “Electrical transformer”, U.S. Patent, 593 138, Nov. 2, 1897, Appl. March 20, 1897, P-252
Tesla: “Electric circuit controller”, U.S. Patents:
609 251, Aug. 16, 1898, Appl. June 3, 1897, P-256.
609 246, Aug. 16, 1898, Appl. Febr. 28, 1898, P-272.
609 247, Aug. 16. 1898, Appl. Mar. 12, 1898, P·276.
609 248, Aug. 16, 1898, Appl. Mar. 12, 1898, P-279.
609 249, Aug. 16, 1898, Appl. Mar. 12, 1898, P-282.
613 735, Nov. 8, 1898, Appl. Apr. 19, 1898, P·285.
“Electrical circuit controller”, U.S. Patents:
609 245, Aug. 16, 1898, Appl. Dec. 2, 1897, P-262.
611 719, Oct. 4, 1898, Appl. Dec. 10, 1897, P-267.
Tesla: “Electrical oscillators”, El. experimenter, July, 1919, A-78.
TESTIMONY U.S. District Court, New York, Oct. 3, 1916. Samuel, M. Kintner and Halsey M. Barrett vs. Atlantic Communication Comp.
ОЧЕРКИ ИСТОРИИ РАДИОТЕХНИКИ ، изд. Академия Наук СССР، Mосква، 1960.
English: ESSAYS OF THE HISTORY OF RADIO ENGINEERING, ed. USSR Academy of Sciences, Moscow, 1960.
Tesla: “Method of and apparatus for controlling mechanism of moving vessels or vehicles”, U.S. Patent 613 809, Nov. 8, 1898, Appl. July 1, 1898, P-363.
United States Reports, vol. 320, Oct. 1942, Oct. 1943, Washington, MARCONI v. s. U.S.
Wheeler L.P. “Tesla’s contribution to high frequency”, Electr. Engineering, New York, August 1943, p. 355, also Tribute: A-211.