Editing Hollow Earth (section)

=== 19th century ===
In 1818, [[John Cleves Symmes, Jr.]] suggested that the Earth consisted of a hollow shell about {{convert|1300|km|mi|abbr=on}} thick, with openings about {{convert|2300|km|mi|abbr=on}} across at both [[geographical pole|poles]] with 4 inner shells each open at the poles. Symmes became the most famous of the early Hollow Earth proponents, and [[Hamilton, Ohio]] even has a monument to him and his ideas.<ref name="atlasobscura">{{cite web|url=http://www.atlasobscura.com/places/hollow-earth-monument |title=Hollow Earth Monument &#124; Atlas Obscura: John Symmes Hollow Earth monument |publisher=atlasobscura.com|access-date=1 November 2015}}</ref> He proposed making an expedition to the [[North Pole]] hole,<ref>{{cite magazine |last1=Simon |first1=Matt |title=Fantastically Wrong: The Real-Life Journey to the Center of the Earth That Almost Was |magazine=Wired |url=https://www.wired.com/2014/10/fantastically-wrong-journey-to-the-center-of-the-earth/ |access-date=18 September 2019}}</ref> thanks to efforts of one of his followers, [[James McBride (pioneer)|James McBride]].

[[J. N. Reynolds]] also delivered lectures on the "Hollow Earth" and argued for an expedition. Reynolds went on an expedition to Antarctica himself but missed joining the [[Wilkes Expedition|Great U.S. Exploring Expedition]] of 1838–1842, even though that venture was a result of his agitation.

Though Symmes himself never wrote a book on the subject, several authors published works discussing his ideas. McBride wrote ''Symmes' Theory of Concentric Spheres'' in 1826. It appears that Reynolds has an article that appeared as a separate booklet in 1827: ''Remarks of Symmes' Theory Which Appeared in the American Quarterly Review.'' In 1868, professor W.F. Lyons published ''The Hollow Globe'' which put forth a Symmes-like Hollow Earth hypothesis, but failed to mention Symmes himself. Symmes's son Americus then published ''The Symmes' Theory of Concentric Spheres'' in 1878 to set the record straight.

[[Sir John Leslie]] proposed a hollow Earth in his 1829 ''Elements of Natural Philosophy'' (pp.&nbsp;449–53).

[[William Fairfield Warren]], in his book ''Paradise Found – The Cradle of the Human Race at the North Pole'' (1885), presented his belief that humanity originated on a continent in the Arctic called [[Hyperborea]]. This influenced some early Hollow Earth proponents. According to Marshall Gardner, both the [[Eskimo]] and [[Mongolian peoples]] had come from the interior of the Earth through an entrance at the [[North pole|North Pole]].<ref>''A Journey to the Earth's Interior'', Marshall Gardner, Mokelumne Hill Pr, 1974 Edition, {{ISBN|0-7873-1192-8}}</ref>