Back in 1818, some 500 heads of state, scientific societies, and universities got what could generously be called one of the more singular letters they’d ever received. The immediate giveaway, perhaps, was the attached document proving the sanity of the sender, an American eccentric named John Symmes.

“I declare the earth is hollow,” Symmes began, “and habitable within; containing a number of solid concentrick [sic] spheres, one within the other, and that it is open at the poles 12 or 16 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.”

He added with aplomb: “I ask one hundred brave companions, well equipped, to start from Siberia in the fall season, with Reindeer and slays [sic], on 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 north-ward of latitude 62; we will return in the succeeding spring.”

There were no takers. But Symmes would eventually earn an enormous audience for his theory in the US, touring tirelessly in the 1820s. He was largely ridiculed, sure, but miraculously managed to get a congressman to petition his colleagues in Washington for the funding to reach the North Pole and discover the 4,000-mile-wide entrance to the "hollow." And while he never got his expedition, dying an early and penniless death, he helped jump-start a glorious new era of exploration—and arguably helped transform American science as we know it.

The Man and the Myth

John Symmes was born in New Jersey in 1780 and grew up on his family’s farm. After a rather valorous career as a captain in the Army, Symmes retired to St. Louis in 1816 to sell supplies to soldiers and Native Americans. It was here where Symmes, a prolific reader who pulled information from all manner of encyclopedias and compendiums, would solidify and unleash his theory that there are entire inhabited worlds underground.

The impetus of it all, according to Peter Sinnema in his essay “10 April 1818: John Cleves Symmes’s ‘No. 1 Circular,’” were studies of Saturn’s rings. Using these to make a bit of a leap in judgement, Symmes reasoned that the planet’s concentric circles must necessarily be duplicated elsewhere in the solar system, including Earth. Our circles are just underground, in the form of at least five hollow spheres that each have their own atmosphere, which forms by clouds (and, we're to assume, the occasional penguin or seal) pouring into two giant holes, one at the North Pole and the other at the south.

These openings are so enormous, in fact, that the northern one unfortunately seems to reach all the way down into Canada and Iceland and Greenland and such, according to Duane A. Griffin in his own essay “Hollow and Habitable Within: Symmes's Theory of Earth's Internal Structure and Polar Geography.” (One of Symmes' few surviving diagrams of his Earth, shown at the top of this story, appeared in The Southern Bivouac in 1887). This would come as some surprise to folks who live in those regions. No problem at all, argued Symmes.

Writes Griffin: “Refraction, Symmes claimed, would bend light rays down into the planet, where reflection among the spherical surfaces would provide a soft, never-ending daylight more than sufficient to light the inner world and warm it well above freezing.” Thus the phenomenon provided not only the light required to sustain life down there, but served as a kind of optical illusion, which tricked the denizens of places like Greenland into thinking they were part of our world as we know it.

The polar holes would also explain how we get wind. James McBride—Symmes’ “patron and collaborator,” according to Sinnema—wrote in his glowing manifesto on the theory that the “long continuation of winds, or regular monsoons, which occur in some parts of the earth, may be supplied by winds sucked into one polar opening and discharged through the other.” (Wind is actually caused by changes in air pressure, or if TV meteorologists are to be trusted, angry clouds blowing on you.)

Halley's model of the hollow Earth. Rick Manning/Wikimedia

Now, Symmes’ wasn’t an entirely original idea. None other than the famed astronomer Edmond Halley was the first to put forward a scientifically reasoned theory of a hollow Earth (and the idea had been bouncing around in various folk traditions for thousands of years before that). Halley argued that “the Earth is represented by the outward Circle, and the three inward Circles are made nearly proportionable to the Magnitudes of the Planets Venus, Mars, and Mercury, all which may be included within this Globe of Earth.” In between those circles, a sort of luminous ether provided the light that allowed life to flourish.

Whether or not Symmes was influenced by this is unclear. Griffin says no in his essay, while Sinnema claims the eccentric picked up the idea from Cotton Mather’s The Christian Philosopher, which focuses extensively on Halley’s theory. Neither Griffin or Sinnema address it, but Symmes also believed the giant entrances to the underworld to be responsible for the aurora borealis. Halley, too, though the phenomenon was due to the ether escaping through cracks in the Earth. (It's actually the sun's particles slamming into our magnetic field.)

Either way, the American people didn’t give a hoot where the theory came from. They ate it up.

Have You Heard the One About There Being Giant Holes in the Earth and There Being, Like, Critters Running Around Down There and Stuff?

To drum up support for his unprecedented journey to the North Pole, Symmes toured much of the Midwest—to mixed reviews. The press largely ridiculed him, but the more gullible in the audiences bought it. Symmes, it seems, was a convincing speaker. And in 1825, he set out east on his most popular tour yet. “Audiences packed halls expecting high amusement from a madman,” writes Griffin. “They went home wondering if Symmes might not be right after all.”

This was not, though, simply a bamboozling of the plebs, à la Dr. Oz. He earned the support of Ohio newspaper editor Jeremiah Reynolds, as well as Major Thomas H. Long, “one of America’s foremost military engineers,” according to Griffin. Symmes even got an invitation from the chancellor of Russia, Count Romanoff, to join him on his polar expedition. Quite cleverly, he told the press that he’d have to accept if his own country couldn’t foot the bill for his own expedition. Writes Griffin: “The ploy tapped a fierce streak of nationalism and bought Symmes—dubbed ‘the Newton of the West’—a new degree of legitimacy and popularity that boosted lecture attendance, earning the team enough to commission new globes and charts for their demonstrations.”

A portrait of John Symmes by the famed painter John Audubon, the man responsible for the most gorgeous work of ornithology ever. Yeah, he pretty much phoned this one in. Wikimedia

Even learned types bought into the theory. In his plea to world leaders and intellectuals, Symmes had vaguely declared: “I select Doctor S.L. Mitchill, Sir H. Davy and Baron Alex. de Humboldt as my protectors.” The latter two of these superstar scientists ignored Symmes’ letters. But Mitchill wrote back, according to Griffin, “giving the Captain ‘great credit for the ingenuity and originality’ of his hypothesis and noting that he ‘should exceedingly rejoice’ if polar exploration were to prove it correct, an outcome that would earn Symmes honor as ‘one of the most profound theorists that ever addressed a wondering people.’” Students at Harvard also lined up behind him ("You're doing what now?" asked their professors), and he also “apparently fared well at other colleges and learned societies.” Even his coverage in the press finally improved.

The Crank That Changed American Science

At the peak of his momentum, though, Symmes’ health failed, and he died in 1829. With him went his theory—but not his influence.

Griffin argues that Symmes had a deep and lasting impact on American science, which at the time was decidedly empiricist, that is, science as we know it, with careful collection of specimens and experimentation and whatnot. Symmes, he writes, provided “a model of a way of thinking that went beyond empiricism toward explanations of the unknown.” The eccentric had spiced up science with that can-do, adventurous American spirit. Sure, that’s a bit cliched at this point, but by harnessing that ethos, Symmes helped kick off a new era of scientific exploration.

The Great United States Exploring Expedition's USS Vincennes in Antarctica's not-at-all-passive-aggressively-named Bay of Disappointment. Naval History and Heritage Command

One of Symmes’ disciples, the newspaper editor Reynolds, eventually helped secure that polar expedition—only the ships went the wrong way. After having a falling out with Symmes and abandoning the theory of the hollow Earth, in 1836 Reynolds lobbied Congress to fund an expedition to the South Pacific. It was approved, and although Reynolds himself didn't set sail, the four-year Great United States Exploring Expedition “surveyed nearly 300 islands and more than 1,500 miles of coastal Antarctica, establishing that it is, indeed, a continent,” writes Griffin. “It constructed more than 200 charts, which became the base of the Hydrographic Office’s collection, and collected thousands of specimens of biological, geological, and anthropological material that contributed to the nucleus of the Smithsonian Institution’s collections.”

Perhaps most importantly, though, Griffin argues that the expedition “set a precedent for federal support for scientific exploration and research,” not to mention that it kickstarted American polar exploration. Thus did one of the more bizarre theories from one of the more bizarre Americans help transform how we do a science here in the States. He may have been wrong, but Symmes was anything but inconsequential.

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