ith the publishing in 1820 of the book titled "Symzonia: A Voyage of Discovery",
by a Captain Adam Seaborn, interest in the possibility of yet another new world was re ignited.
This book describes a journey of Captain Seaborn into the hollow of the Earth. Although
the prospect for a land within the hollow of the Earth was initially proposed
by Sir Isaac Newton and Edmond Halley in 1702 in the "Lunar Theory", Seaborn saw fit
to name the lands he had discovered for John Cleves Symmes, Jr., a more resent proponent of the
hollow Earth theory. In a self published pamphlet, Symmes had stated "I declare the earth is
hollow, habitable within; containing a number of solid concentric spheres; one within the other,
and that it is open at the pole twelve or sixteen degrees. I pledge my life in support of this
truth, and am ready to explore the hollow if the world will support and aid me in the undertaking."
t is not entirely clear if Symmes was familiar with the works of Newton and Halley of some
120 years previous. in which Halley state 'Sir Isaac Newton has demonstrated the Moon to be
more solid than our Earth, as 9 to 5; why may we not suppose four ninths of our globe to be
cavity?' (Phil Trans 1692 xvi 568). Halley goes on to state 'I have adventured to make these
Subterranean orbs
capable of being inhabited.' Regardless of Symmes awareness of these earlier works, Captain Seaborn has credited Symmes with the inspiration for his voyage of discovery as presented in "Symzonia: A Voyage of Discovery". Seaborn describes the interior land thus "The next day we observed the sun to the south of us, and nearly over head, and the compass began to traverse imperfectly. We had a regular recurrence of day and night, though the latter was very short, which I knew was occasioned by the rays of the sun being obstructed by the rim of the earth, when the external side of the part we were on turned towards the sun. The nights were not dark, when no clouds intervened to obstruct the rays of the sun, reflected from the opposite rim, and from a large luminous body northward, in the internal heavens, which reflected the sun as our moon does, and which I judged to be the second concentric sphere, according to Capt. Symmes." While the exact nature of this internal structure remained unclear to Seaborn, his description was not consistent with a bright luminous body predicted by Euler or Leslie.
