Paradigm Lost: Nikola Tesla's True Wireless Page 26

17. See the article on diffraction in the 11th edition of the Encyclopedia Britannica, vol. 8, 1911. https://en.wikisource.org/wiki/1911_Encyclop%C3%A6dia_Britannica/Diffraction_of_Light/11. Also, for a modern treatment see Y. T. Lo, Y. T. and S. W. Lee, Antenna Handbook, (Van Nostrand-Reinhold, NY, 1988) sec. 29.

18. R. W. P. King and S. Prasad, Fundamental Electromagnetic Theory and Applications, (Prentice Hall, Upper Saddle River, New Jersey 1986) chapter 7.

19. Jules Stratton, Electromagnetic Theory, (McGraw-Hill, New York. 1941), secs. 9.22–9.24.

20. Chen-Pang Yeang, Probing the Sky with Radio Waves (University of Chicago Press, Chicago. 2013). I am greatly indebted to this source.

21. Henri Poincaré and F. King Vreeland (translation), Maxwell’s Theory and Wireless Telegraphy, (McGraw-Hill, New York, 1904) p. 161. Tesla might have countered by asserting that the Branly coherer responds to the electric field — not the magnetic field — and the earth weakens the former.

22. L. W. Austin, “Some Quantitative Experiments in Long Distance Radio Telegraph,” Reprint No. 159, Bulletin of Bureau of Standards, vol. 7, no. 3, Feb. 1, 1911; see also Robison, 1918, p. 228.

23. Watson, G. N. “The Transmission of Electric Waves Around the Earth,” Proc Royal Society (London) Series A, vol. 95, July 15, 1919, pp. 546–553.

24. Heinrich Hertz, Electric Waves, (Dover Books, Mineola NY, reprint of Macmillan book 1893) chapter 8 (dating from 1888, especially Fig. 26).

25. Kuhn, page 43.

26. Samuel Robison, Robison’s Manual of Radio Telegraphy and Telephony for Naval Electricians (U.S. Naval Institute, Annapolis, MD, 1918) p. 131. He asserts that the directivity behavior of the “flat top antenna” attributed to Marconi, which involves a long piece of wire or wires parallel to the ground, is still not understood.

27. L. J. Chu, “Growth of the Antennas and Propagation Field Between World War 1 and World War 2. Part 1, Antennas,” Proceedings of the IRE, vol. 50, no. 5, May 1962, pp. 685–7.

28. Charles Burrows, “The History of Radio Propagation up to the End of World War I,” Proceedings of the IRE, vol. 50, no. 5, May 1962, pp. 682–684.

29. Note that Marconi had described arrays formed from inverted L antennas as early as 1906, as noted in G. W. Pierce below. The horizontal elements were much longer than the vertical ones, a configuration not suggested in Tesla’s Fig. 16. G. W. Pierce, Principles of Wireless Telegraphy, (McGraw-Hill, New York, 1910) Chapter 25. See also Practical Wireless Telegraphy, Elmer Bucher, Wireless Press, 1917, sec. 233. Here, the horizontal portion of the antenna is nearly a mile long.

30. See G. Marconi, “On Methods Whereby the Radiation of Electric Waves May Be Mainly Confined to Certain Directions, and Whereby the Receptivity of a Receiver May Be Restricted to Electric Waves Emanating from Certain Directions,” Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character 77.518 (1906): 413–21; Electrician, vol. 60, 1908, p. 883.

31. Pierce, p. 298.

32. Zenneck and Seelig, Sec. 202–204. The book contains the reference to Von Hoerschelmann, which was published in German as a dissertation in 1911.

33. Aitken, p. 267.

34. Nahin, pp. 142–143.

35. Bernard Carlson, Tesla: Inventor of the Electrical Age, (Princeton U. Press, Princeton NJ, 2013) p. 200–202; note that some images were the result of multiple exposures where Tesla was not present when the sparks were being generated, see pp. 297–299.

36. T. C. Martin, editor, The Inventions, Researches and Writings of Nikola Tesla, 1893; republished by (Barnes and Noble, NY, 1992) Chapter 6. From the lecture: “The reason why no pain in the body is felt, and no injurious effect noted, is that everywhere, if a current be imagined to flow through the body, the direction of its flow would be at right angles to the surface; hence the body of the experimenter offers an enormous section to the current, and the density is very small, with the exception of the arm, perhaps, where the density may be considerable… The expression of these views, which are the result of long continued experiment and observation, both with steady and varying currents, is elicited by the interest which is at present taken in this subject, and by the manifestly erroneous ideas which are daily propounded in journals on this subject.” Tesla misses the essential point here — the very shallow depth of penetration of the energy. The arm plays no special role. Notice that he takes a swipe at other workers’ “erroneous ideas.”