Editing Wireless power transfer (section)

=== 19th century developments and dead ends ===

The 19th century saw many developments of theories, and counter-theories on how electrical energy might be transmitted. In 1826, [[André-Marie Ampère]] discovered a connection between current and magnets.  [[Michael Faraday]] described in 1831 with his [[Faraday's law of induction|law of induction]] the [[electromotive force]] driving a current in a conductor loop by a time-varying magnetic flux. Transmission of electrical energy without wires was observed by many inventors and experimenters,<ref>[[Luigi Galvani]] (1791), Peter Samuel Munk (1835), [[Joseph Henry]] (1842), Samuel Alfred Varley (1852), [[Edwin Houston]], [[Elihu Thomson]], [[Thomas Edison]] (1875) and [[David Edward Hughes]] (1878)</ref><ref>{{cite book |first1=T. K. |last1=Sarkar |first2=Robert |last2=Mailloux |first3=Arthur A. |last3=Oliner |first4=M. |last4=Salazar-Palma |author4-link=Magdalena Salazar Palma|first5=Dipak L. |last5=Sengupta |title=History of Wireless |publisher=John Wiley & Sons |year=2006 |pages=258–261 |isbn=9780471718147 |author-link1=Tapan Sarkar |author-link3=Arthur A. Oliner}}</ref><ref>Christopher H. Sterling, Encyclopedia of Radio 3-Volume, Routledge – 2004, page 831</ref> but lack of a coherent theory attributed these phenomena vaguely to [[electromagnetic induction]].<ref>{{cite book |first=W. Bernard |last=Carlson |title=Innovation as a Social Process: Elihu Thomson and the Rise of General Electric |publisher=Cambridge University Press |year=2003 |pages=57–58}}</ref> A concise explanation of these phenomena would come from the 1860s [[Maxwell's equations]]<ref name="Shinohara">{{cite book |url=https://books.google.com/books?id=TwegAgAAQBAJ&pg=PP11 |last=Shinohara |year=2014 |title=Wireless Power Transfer via Radiowaves |page=11 |publisher=John Wiley & Sons |isbn=9781118862964}}</ref> by [[James Clerk Maxwell]], establishing a theory that unified electricity and magnetism to [[electromagnetism]], predicting the existence of electromagnetic waves as the "wireless" carrier of electromagnetic energy. Around 1884 [[John Henry Poynting]] defined the [[Poynting vector]] and gave [[Poynting's theorem]], which describe the flow of power across an area within [[electromagnetic radiation]] and allow for a correct analysis of wireless power transfer systems.<ref name="Shinohara" /><ref name="Angelo">{{cite book |last1=Angelo |first1=Joseph A. |title=Encyclopedia of Space and Astronomy |publisher=Infobase Publishing |date=2009 |pages=292–293 |url=https://books.google.com/books?id=VUWno1sOwnUC&pg=PA293 |isbn=978-1438110189}}</ref> This was followed on by [[Heinrich Rudolf Hertz]]' 1888 validation of the theory, which included the evidence for [[radio wave]]s.<ref name="Angelo" />

During the same period two schemes of wireless signaling were put forward by [[William Henry Ward]] (1871) and [[Mahlon Loomis]] (1872) that were based on the erroneous belief that there was an electrified atmospheric stratum accessible at low altitude.<ref>{{cite book |first=Christopher |last=Cooper |title=The Truth About Tesla: The Myth of the Lone Genius in the History of Innovation |publisher=Race Point Publishing |year=2015 |pages=154, 165}}</ref><ref>{{cite book |first1=Theodore S. |last1=Rappaport |first2=Brian D. |last2=Woerner |first3=Jeffrey H. |last3=Reed |title=Wireless Personal Communications: Trends and Challenges |publisher=Springer Science & Business Media |year=2012 |pages=211–215}}</ref> Both inventors' patents noted this layer connected with a return path using "Earth currents"' would allow for wireless telegraphy as well as supply power for the telegraph, doing away with artificial batteries, and could also be used for lighting, heat, and motive power.<ref>{{cite book |first=Christopher |last=Cooper |title=The Truth About Tesla: The Myth of the Lone Genius in the History of Innovation |publisher=Race Point Publishing |year=2015 |pages=154}}</ref><ref>{{Cite web |url=https://earlyradiohistory.us/sec021.htm |title=21. Fakes, Frauds, and Cranks (1866–1922) |website=earlyradiohistory.us}}</ref> A more practical demonstration of wireless transmission via conduction came in [[Amos Dolbear]]'s 1879 magneto electric telephone that used ground conduction to transmit over a distance of a quarter of a mile.<ref name="Christopher Cooper 2015, page 165">{{cite book |first=Christopher |last=Cooper |title=The Truth About Tesla: The Myth of the Lone Genius in the History of Innovation |publisher=Race Point Publishing |year=2015 |pages=165}}</ref>