The Bizarre 19th-Century Push for a 'Hollow Earth' Expedition

On April 10, 1818, a curious letter was sent widely to colleges, scientists and government officials in the United States. It read:

“To all the World: I declare that the earth is hollow and habitable within; containing a number of solid concentric spheres, one within the other, and that it is open at the poles twelve or sixteen degrees. I pledge my life in support of this trust, and am ready to explore the hollow, if the world will support and aid me in my undertaking.”

The declaration was signed by Captain John Cleves Symmes, a distinguished veteran of the War of 1812, father of 10, and an ardent promoter of the “hollow Earth” theory. Symmes and other 19th-century thinkers believed that there were openings at the North and South poles leading to a habitable, Eden-like interior of the planet with its own sun, oceans and perhaps even a parallel race of humans.

The only way to know if the hollow Earth theory was true was to mount an expedition to find these polar entryways. Symmes continued:

“I ask one hundred brave companions, well equipped, to start from Siberia, in the fall season, with reindeers and sleighs, in the ice of the frozen sea; I engage we find a warm and rich land, stocked with thrifty vegetables and animals, if not men, on reaching one degree northward of latitude 82; we will return in the succeeding spring.”

Perhaps anticipating a skeptical response, Symmes attached a “certificate of sanity” to his letter. He still didn’t receive a single positive reply.

Incredibly, Symmes' wild idea didn’t die in 1818. The hollow Earth theory gained enough traction to make it all the way to the desk of President John Quincy Adams. And Symmes, in a roundabout way, set the gears in motion that ultimately helped inspire the U.S. Exploring Expedition, which launched the nation’s first scientific voyage to Antarctica in 1838.

Legends about subterranean passages, mythical creatures and hidden civilizations deep inside the Earth go back thousands of years, but the famed astronomer Edmond Halley (of comet fame) was one of the first scientists to take the hollow Earth theory seriously.

In 1681, Halley presented a paper to the Royal Society that aimed to solve a geological anomaly. Ship captains reported that their compasses did not always point true north. The direction of the compass needle shifted depending on where and when it was read. Halley spent years collecting compass data and concluded that there was more than one “north” because there were multiple layers inside the Earth.

According to Halley’s theory, the Earth was a hollow shell with three concentric spheres inside it. The movements of those inner spheres were what created the magnetic anomalies. Halley theorized that there were spaces between the spheres that might even harbor life.

The idea of a habitable, hidden world inside our own captured people’s imaginations in the 18th and early 19th centuries, but none more so than Symmes. In his version of the hollow Earth, there were five concentric layers bathed in light from an internal sun. The brilliantly colored lights visible in northern and southern latitudes—aurora borealis and aurora australis—were reflections from the inner sun.

Symmes also believed that Arctic animals like reindeer and bears escaped to the warmth of the inner realm in the winter and reemerged in the spring.

After his 1818 declaration failed to drum up support, Symmes spent the next 10 years delivering lectures on hollow Earth theory to anyone who would listen, including the U.S. Congress, which twice voted on his petition for a federally funded Antarctic expedition (he got 25 “yays” the second time).

In 1820, an author named Captain Adam Seaborn published a popular novel called Symzonia: A Voyage of Discovery about a fantastical journey down one of “Symmes’ holes,” as they became known. (Most scholars think “Captain Seaborn” was actually Symmes.) But the biggest boost to Symmes' credibility was an 1826 treatise called Symmes’ Theory of Concentric Spheres by acolyte James McBride.

McBride’s book was classic pseudoscience, says Gillen D’Arcy Wood, an English professor at the University of Illinois.

“There's a blur of technical language and a cherry-picking of science,” says Wood, who researched Symmes and McBride for his book Land of Wondrous Cold: The Race to Discover Antarctica and the Secrets of its Ice. “There's an invoking of what sounds like serious scientific inquiry, but it's really a kind of smokescreen for preposterousness.”

McBride repeated Symmes’ call for a government-funded Antarctic expedition, calculating that the habitable surfaces of the Earth would be increased “ten-fold.” Symmes, a military veteran, brought an air of imperial ambition to the enterprise.

“I think they're expecting colonizable land,” says Wood, “like an extension of terrestrial Earth with potentially arable land, verdant grasslands and tropical forests.”

One of the most zealous converts to Symmes’ theory was Jeremiah Reynolds, a newspaper editor who quit his job to join Symmes on his hollow Earth lecture circuit. After a few years, though, Reynolds lost faith in Symmes’ more fantastical ideas about subterranean suns and civilizations and redirected his energies toward promoting a legitimate scientific expedition to Antarctica.

"In true American ‘huckster’ style, Reynolds doesn't look back,” says Wood. “He doesn't spend time explaining; he just moves forward. ‘Forget hollow Earth, this is all about Antarctica and exploration now.’”

In 1826, Reynolds went to Washington, D.C. and lobbied for the U.S. to beat Britain and France—the other major maritime powers—to the South Pole. Reynolds’ perseverance won the admiration of President John Quincy Adams, who noted in his diary that Reynolds had abandoned Symmes' theory—which had been “so much ridiculed”—and was now proposing a true voyage of exploration. “May it be my fortune, and my praise,” wrote Adams, “to accelerate its approach."

Adams was a strong proponent of science and exploration, and, in 1828, Reynolds’ Antarctic dream appeared to be on the verge of realization. In a diary entry dated November 17, Adams noted: “The South Pole Expedition—Jones to command—Instruments to be purchased.” But just two weeks later, Adams lost the 1828 presidential election to Andrew Jackson and the South Pole expedition was abandoned.

Undaunted, Reynolds solicited private funding for an 1829 expedition to Antarctica. The ill-fated journey made it as far as the Palmer Peninsula, but quickly turned back. The crew mutinied in Chile and abandoned Reynolds, who had to wait two years for a ride back to the U.S.

After all that, Reynolds still wasn’t done. In 1836, he addressed the House of Representatives and made a lengthy pitch for the scientific and economic benefits of an American voyage to the Antarctic. Let the British and the French fight over the North Pole, Reynolds said. “For us a wider range, a nobler field, a prospect of more comprehensive promise, lies open in the south.”

“The crackpot hollow Earth theory is totally gone,” says Wood, “Now it’s all about imperialism, national pride and the need to invest in science.”

And it worked. In 1836, Congress finally approved funding for a polar expedition. Adams, now a U.S. congressman representing Massachusetts, cast one of the deciding votes. When Adams broke the good news to Reynolds, he said “he could now die content.”

The six-vessel U.S. Exploring Expedition of 1838-42, also known as the Wilkes Expedition, charted vast expanses of the southern seas and brought along botanists, naturalists and taxidermists to collect newly discovered specimens. One person they didn’t bring along, however, was Jeremiah Reynolds, who still “carried the odor of hollow Earth theory,” says Wood.