Edmond Halley's Extravagant Hypothesis

“We have Adventured to Make the Earth Hollow”: Edmond Halley’s Extravagant Hypothesis

Peter W. Sinnema University of Alberta

This essay revisits Edmond Halley’s schema of a multi-sphered, hollow earth, presented to the Royal Society in 1691 as a hypothetical resolution to the problem of magnetic variation. I open my investigation with a reading of Michael Dahl’s ªnal portrait of the great astronomer (1736), which enig- matically reproduced a diagram of the hollow earth that Halley had appended to his original “Account [. . .] of the Internal Parts of the Earth” in the Philosophical Transactions. My essay has the goal of enhancing our appreciation not only of Halley’s aptitudes as a theorist of the earth sciences, but as the dexterous practitioner of a language felicitously attuned to the early development of that ªeld. I provide a comprehensive exposition of Halley’s self-styled “Extravagant” hypothesis and argue that his attachment to it was sustained by his adherence to the tenet of a divinely ordained, natural economy. I also position Halley’s “Account” as the originary moment of a literary sub-genre—the hollow earth fantasy or romance—that ºourished in England and America in his wake. Today, Dahl’s painting gestures simultaneously to Halley’s conception of a habitable inner earth and to a literary tradition that embraced that idea as its central imaginary novelty.

1. Halley’s Enigmatic Legacy Portrait In 1736, an 80-year-old Edmond Halley, digniªed by the academic robes of his alma mater, Queens College Oxford, sat down at the brush of trans- planted Swedish artist Michael Dahl for his ªnal ofªcial portrait.1 (Fig. 1) By the time he posed for Dahl, Halley occupied a rank of distinction among practical philosophers of the early Enlightenment. His manifold achievements included authorship of the ªrst catalogue of stars in the 1. Halley left Oxford in 1676 without completing a degree, but was created M.A. per literas regias in December 1678.

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Figure 1. Michael Dahl, “Dr E Halley, Aged 80.” (1736) © The Royal Society.

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southern hemisphere, the laying of actuarial foundations for life insurance and annuities, his correct prediction of the return in 1758, 1835, and 1910 of a bright periodic comet that today bears his name, his steady en- couragement (and personal ªnancing) of Isaac Newton in the writing and publication of his world-changing Principia Mathematica,2 his 1703 investiture into the Savilian professorship of geometry, and some sixteen years’ service as Astronomer Royal. Halley’s intellectual fertility, like his reputation in senectitude, was prodigious. Viewers may reasonably look to the aged astronomer’s legacy portrait for a visual commemoration of his dis- tinctive charisma. Herein I investigate Dahl’s painting as a most peculiar memorial, one of two Halley portraits in the Royal Society’s picture collection3 that serve as reminders of his many contributions to that institution in its pursuit of “Natural Knowledge”: as an elected Fellow from 1678 (re-elected 1700) until his appointment as Clerk in 1686, in which ofªce he also edited the Philosophical Transactions for six years—contributing more than eighty pa- pers of his own over the course of nearly six decades—and as the Society’s secretary from 1713–21. My discussion of the portrait’s formal properties, however, moves quickly into a more protracted consideration of the esoteric geophysical theory to which it pays homage, a hypothesis about magnetic variation (or declination) and the earth’s shell-like structure that Halley presented to the Society in 1691 and published in the Philosophical Transactions the following year. Although the connection between portrait and scientiªc proposition has been commented upon before—most nota- bly by Patricia Fara in the second chapter of Fatal Attraction (2005) and again in the pages of the Notes and Records of the Royal Society (2006), but also cursorily in other Halley biographies and histories of hollow earth theory4—this particular instance of ideological provenance awaits a comprehensive exposition that attends sympathetically to the language and imagery of its original articulation. My account of the story behind Dahl’s portrait has the goal of further enhancing our appreciation not only of Halley’s aptitudes as a theorist of the earth sciences, but as the dexterous practitioner of a language felicitously attuned to the early development of that ªeld—that is, as a gifted and persuasive rhetorician on matters geological and cosmological. I also

2. “Stimulus, critic, sustainer, editor, publisher: bringing forth the Principia was [Halley’s] greatest contribution to natural knowledge” (Cook 1998, p. 178). 3. The second, by Thomas Murray, is discussed brieºy below. 4. See respectively Fara 2005, pp. 41–50 and 2006, pp. 199–201; Armitage 1966, pp. 70–75; Cohen 1972, pp. 62–66; Kollerstrom 1992, pp. 185–192; and Standish 2006, pp. 15–36.

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want to argue, with necessary brevity, for Halley’s self-styled “Extrava- gant” hypothesis as the originary moment of a literary sub-genre—the hollow earth fantasy or romance—that ºourished in England and America in his wake. Today, Dahl’s painting gestures simultaneously to Halley’s conception of a habitable inner earth and to a literary tradition that embraced that scheme as its novum or “central imaginary novelty” (Csicsery- Ronay 2008, p. 47). In both cases, I draw attention to a shared assumption about cosmic structure, the belief that nature persistently displays frugal- ity of composition. Halley’s stubborn attachment to the hollow earth model cannot be explained biographically. Rather, his adherence, however guarded, to a theological doctrine commonly held in the seventeenth century—that creation is “as copious as possible” because “that would log- ically be part of the Creator’s plan” (Standish 2006, p. 32)—also sustained his allegiance to the radical globe-within-a-globe hypothesis. In Halley’s dotage, as Duane Griffen puts it, this idiosyncratic theory remained “a perfectly plausible proposition” (Griffen 2012, p. 3), not only because it responded cogently to breaches in empirical knowledge but because it transitioned smoothly from geophysics to the related domain of theology—to the idea that a muniªcent Providence would prescribe the habitability of a cavernous underworld. Dahl’s portrait attests to the hollow earth idea’s perseverance into the 1730s, less as the quirky persuasion of its inventor than as a scientiªcally viable response to the question of magnetic variation that also harmonized with the law of utility. Divine economy in turn came to function as the base logic in various works of prose ªction, revealing ideological linkages between the scientiªc theory and its subsequent, imaginative representations. One of the earliest hollow earth novels, the anonymously authored Voyage to the World in the Centre of the Earth (1755), demonstrates my point with exemplary gusto. This “history” embedded its rudimentary chthonic setting within the grander mise-en-scène of a providentially—and efªciently—organized universe. The result is an analogically complex fantasy, which opens with the unnamed narrator tumbling into a crevice at the top of Mount Vesuvius, falling through “a little more than a hundred Miles” of outer crust, and landing in a “World . . . plac’d directly in the Centre of our Earth” (Voyage 1755, p. 22). In this pleasant subterranean kingdom, where “everything grows spontaneous” thanks to a constant and agreeable temperature, the narrator encounters an abstemious civilization whose moral perfection is akin to “the Christian Religion in its Purity, and without Adultera- tion” (Voyage 1755, p. 87). The Voyage is a prolonged exploration of an idealized political and social state that contrasts violently with the real- ity of superterranean existence: whereas “Plainness and Sincerity is the

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Characteristic” of life underground, with the Europeans all is “Shew and Ostentation” (Voyage 1755, p. 250). The novel ultimately suggests that a hollow earth is typologically in- dicative of a sublime providential plan—a point of contact between Hal- ley’s hypothesis and the hollow earth tradition that was to take root in early nineteenth century America, as I discuss in my concluding remarks on that tradition’s seminal work, Symzonia. At one point the Voyage’s narrator is introduced to Mr. Thompson, another earthling who has lived hap- pily underground for one hundred years as a sort of benign natural philosopher. Thompson’s experiences as a submerged surface dweller lead to his ªrm conviction that every planet in the universe must be either inhabited or suitable for habitation. “For my own Part,” Thompson tells his rapt listener, till by mere Accident I was thrown upon this Central World, I had no Idea of there being one, and inhabited, in the Bowels of the Earth. In short, these Things are Wonderful to us; yet tho’ we cannot comprehend, our Wonder ceases, when we consider that all this is the Work of an omnipotent Being. How vain are we then to attempt to search into his Ways, and to pronounce those Things im- possible, that we cannot comprehend? [. . .] [S]illy man [. . .] has the Arrogance to say, that this small Grain of Sand which we pos- sess, is the Whole that God created to be inhabited. Those stupen- dous Bodies which are to be seen from the World I come from [. . .] have their Atmospheres, which can be of no Use to us, nor any in the Universe, unless they be created for the same Use that ours is, viz. To be the great Cause of Life; and that they are, is evident from this, GOD CREATES NOTHING IN VAIN. (Voyage pp. 105, 108) Dahl’s “Dr E Halley, Aged 80” honored the sitter’s hypothesis about a terrestrial model similarly demonstrative of God’s economical management. The canvas’s subject matter presages Thompson’s philosophy: a hollow earth emphatically declares “the work of an omnipotent Being”—work that must decry the structural inefªciencies of a solid globe, with its unexploitable and hence squandered interior. Dahl’s portrait signals the conventions of a branch of luminary portraiture originating in the early sixteenth century that specialized in repre- senting members of the fraternity of mathematicians and astronomers. Its chief iconographic features, “the representation of the person at half- length in a physical space, and the activity of the hands [typically] at a worktable with instruments of measurement and writing [. . .] serve a kind of collective commemorative function” (Meyer 1995, p. 108). Such

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portraits emphasized dignity of comportment and the analogical function of both background and gesture in expressing the essence of the individual character—what Manuel Portela calls the “symbolic iconography of the genre,” in which painters portrayed “a self who was conscious of the presence of others and whose character showed in outward appearance, dress and manners [. . .] the idealized subjectivity of the gentleman” (Portela 2005, p. 358). Halley’s consciousness “of the presence of others” is registered in a pen- etrating gaze that addresses directly the viewer’s. His still erect frame foregrounded against opaque drapes pulled aside to reveal bookshelves laden with substantial tomes elicits the gravitas of the educated burgher class, whose prosperous members held Dahl in high esteem and whose patronage made him for a time the busiest and richest portraitist in Eng- land. His painting adheres with seeming ªdelity to portrait convention, demonstrating the artist’s invention within the fairly limited terms of portraiture’s common practice as a systematic art that elevates and enno- bles the subject. “The repertoire of portrait attitudes in the eighteenth century was constrained by the need to portray sitters pleased, in good hu- mor, and suitably elevated in character”—a “decorous repertoire” (Meyer 1995, p. 47) that distinguished portraiture from history painting, which allowed for a greater variety of sentiments in its subjects. My comments on the sitter’s attitude and its deeper import lead us to consider the two other principal elements in Dahl’s painting, boldly illu- minated features that draw the viewer’s eye to the lower half of the canvas. These features—the exquisitely rendered hands and the sharply limned, perspectivally anomalous, black and white diagram—confute the portrait’s conventionality. What exactly is Halley holding in his right hand, the hand traditionally used by gentlemen portrait sitters for important or- atorical gestures? If “hands are meant to speak” in the “rhetorical style of portraiture” (Meyer 1995, p. 54) typical of the post-Restoration period, the question posed by Dahl’s portrait is what Halley’s right hand is saying with its purchase on that curious drawing. It clearly bears instrumental meaning, but its signiªcance is not immediately evident, making ambig- uous this otherwise readily intelligible portrait. In the diagram a series of concentric spheres are rendered perfectly round, allowing for an unrestricted, anterior scrutiny that permits appre- hension of such details as the transecting line, the letters along its axis, and the not quite legible caption, even while their position on a piece of paper depicted in two point perspective would suggest that they should be elliptical to accord visually with the angled plane on which they are in- scribed. Dahl ºaunts the rules of perspective, while Halley tips the

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diagram forward, inviting its close study, his reposed left hand pointing loosely toward the shaded sphere at its very center acting as an additional index of its importance. Halley’s attitude thus underscores the enigma at the heart of the painting: to grasp the diagram’s meaning is to grasp what it is that this eminent man of science was intent on advertising for posterity at a ripe old age—his ongoing, arguably surprising commitment to a hypothesis about the earth’s hollow structure that he had ªrst articulated some forty-ªve years earlier. Dahl’s portrait marks a singular episode in the annals of Halley’s posthumous repute, although it cannot be said to enjoy a unique position within the archive of Halley portraiture, which consists of ªve known likenesses.5 When a much younger Halley was painted by Thomas Mur- ray, for example, he was also portrayed holding a diagram, in this case in his left or appurtenant hand. Its simple combination of parabolic and straight lines relates to Halley’s polynomial-based account of cubic and quartic equations published in the Transactions of 1687, dating the portrait to that year. Murray’s painting signiªes Halley’s entitlement to the Savilian Geometry Professorship and to the honor of serving as secretary to the Royal Society in the year of the Principia’s publication, as the painting’s superscription clearly proclaims. Here, the picture-within-a- picture betokens scientiªc intellectuality and achievement. Another portrait, attributed to Isaac Whood (1720?), is similarly commemorative of a speciªc premise: Halley’s accurate prediction of the pas- sage of a solar eclipse that darkened southern England on 22 April 1715. Halley, in fact, introduced to the scientiªc world the modern eclipse map. It showed with remarkable precision the track of the moon’s umbra as an oval disk—in Whood’s careful depiction of the crumpled map to which Halley’s right hand points, a black ellipsoidal shape resting within a dark diagonal band. It revolutionized astronomical observation by enabling the forecasting of eclipses based on improved mathematical tables of solar and lunar motion. What differentiates the latter portrait’s topical inclusion of a monotoned chart from Dahl’s portrait, however, is that the eclipse map proved to be a near unerring pictorial anticipation of an actual cosmic event. The map enjoys an approximative function in Whood’s portrait and its privileged position there supports the contention that Halley was “the ªrst thematic mapmaker to merit the name cartographer” (Armitage 2009, n. p.). Whereas the Murray and Whood portraits chronicle

5. See Cook’s prefatory note on “Portraits of Halley” in his Edmond Halley, p. xv, for a brief account of the portraits and their dates, which I draw upon here.

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moments of demonstrable achievement, vocational and scientiªc, Dahl’s portrait does something quite different: it solemnizes a strictly hypothetical and highly conjectural proposition that Halley had ªrst made in his mid-thirties. Although there is abundant evidence in Halley’s writings of a wry and self-conscious tentativism, there are no signs of irony in either Dahl’s treatment of his subject or in Halley’s frontal posture. Let us take the portrait at face value, then, and ªnd in it the remarkably tenacious hold on a pre-eminent scientist of his own original theory about the earth’s hollowness.

2. Halley’s Habitable Hollow Earth For that is what the diagram illustrates: a hollow earth, made up of an outer shell that is one of three nested, equidistant, and equally-thick circles, at the center of which is a solid sphere—an inner space constituted by “Subterraneous Orbs capable of being inhabited” (Halley 1692, p. 557). The diagram is in fact an accurate reproduction of an illustration Halley had appended to the print version of his 1691 Royal Society lecture, published in Philosophical Transactions (#95) as “An Account of the Cause of the Change of the Variation of the Magnetical Needle; With an Hypothe- sis of the Internal Parts of the Earth.” (Fig. 2) In this essay Halley addressed the seemingly insoluble question “of the slow changes suffered by the variation of the compass” (Armitage 1966, p. 71), itself a project that had signiªcant repercussions for mariners of the Restoration period, when the expansion of imperial inºuence was vexed by navigators’ incapacity to measure accurately longitudinal position.6 Halley’s original diagram and its re-presentation in Dahl’s portrait therefore have direct lineage in a history of deliberation about a particular geophysical conundrum: the “puzzle of magnetic variation” that gave rise to an “extensive literature in seventeenth-century England [. . .] as the na- tion emerged as a maritime power with increasing colonial interests” (Kubrin 1990, p. 58). Dahl’s portrait must be read as part of this volumi- nous literature, an oeuvre that, prior to Halley’s “Account,” included important arguments about magnetism by William Gilbert in De Magnete (1600), Henry Gellibrand in his Discourse Mathematical on the Variation of the Magnetical Needle (1635), Henry Phillippes in The Sea-Mans Kalendar 6. See Dava Sobel’s Longitude: The True Story of a Lone Genius who Solved the Greatest Scientiªc Problem of His Time (1995) for a popular history of the “longitude problem” and John Harrison’s horological solution to it. Sobel recalls in some detail Halley’s personal im- mersion in the “quest for longitude” and his support for Harrison as a member of the Board of Longitude.

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Figure 2. Edmond Halley, Schema of the Hollow Earth. Philosophical Transac- tions #95 (1692). The stave containing bass and treble clefs at the top of the diagram, along with the vertical lines descending from its foot on the left, are part of a paper saving illustration to Francis Roberts’ “Discourse concerning the Musical notes of the Trumpet” also in Philosophical Transactions #95 (1692), pp. 559–563.

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(1669), and Johannes Hevelius in a letter to Philosophical Transactions of 1670.7 Halley’s own contributions to this lively debate about magnetism con- stitute a sustained theme in a diverse career and, as Alan Cook has pointed out, “foreshadowed the modern world” in their distinction from the magnetic theories of his predecessors (Cook 2001, p. 477). In the 1692 “Ac- count” Halley refers speciªcally to another Philosophical Transactions publication (1683) in which he advanced “a Theory of the Variation of the Magnetical Compasss, wherein [. . .] I came at length to this general conclusion, That the Globe of the Earth might be supposed to be one great Magnet” (Halley 1692, pp. 563–564). Both discourses served as declarations of Halley’s decades-long preoccupation with the question of magnetic variation, a pursuit that eventually led him to take command of Their Maj- esty’s eighty-ton pink, the Paramore for three voyages in the North and South Atlantic Oceans (1698–1701). Under Queen Mary’s urging “to endeavour to get full information of the Nature of the Variation of the Compasse over the whole Earth” (quoted in Waters 1990, p. 184), Halley undertook “the world’s ªrst scientiªc mission” (Wakeªeld 2005, p. 5) aboard the Paramore, testing various methods of longitudinal measurement. His extensive maritime experiments led to the commercial publication of magnetic variation charts in 1701–02, registers that “had the ines- timable virtue of making visible, as it were, magnetic variation, that inexplicable invisible phenomenon” (Waters 1990, p. 195). Just as Hal- ley’s charts “made visible” the latent forces of magnetic variation, so the inclusion of the multi-sphered diagram in Dahl’s portrait is emblematic of a spirited scientiªc controversy. Viewers curious about its deeper meaning must turn to Halley’s “Account” and its hypothesis about a hollow earth as a solution to the magnetic puzzle—a theory whose commemoration in the ªnal portrait has suggested to more than one historian that it was Halley’s “proudest achievement” (Kubrin 1990, p. 71).8

7. See Kubrin 1990, pp. 58–59 for a summary of these arguments. Alan Cook (2001) provides a useful if brief summary of theories about magnetic declination by such pre- Halley ªgures as Peter Peregrinus, John Cabot, Robert Norman, and Guillaume de Nautonier. 8. Patricia Fara proposes that the inclusion of the diagram in Dahl’s portrait may have been Halley’s attempt “to display the foolishness of his youth, or else advertise his magnetic success to counter his mediocre reputation as Astronomer Royal” (2007, p. 581). See also the same author’s brief discussion of “Edmond Halley’s last portrait” (2006). Fara, however, is in a distinct minority in this interpretation. See Standish for a view more in line with Kubrin’s and my own: “Of the hundreds of projects he’d involved himself in, with accolades given for his work in dozens of areas, [Halley] remained fond and proud enough of his hollow earth theory to have it memorialized in what he must have suspected would be the last ofªcial portrait done of him” (Standish 2006, p. 36).

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Two observations about the originality and inºuence of the “Account” set the stage for my further consideration of its argument. Firstly, although other natural philosophers seem to have preªgured the hollow earth idea, Halley’s theory of a habitable inner world remains his unique invention. In his Royal Society lecture of February 1688, for example, Robert Hooke proposed that the biblical deluge was a result of the earth’s “Liquid Water” escaping the “Shell of the Egg” that constitutes the globe’s hard surface (quoted in Oldroyd 1989, p. 227). Hooke’s conve- nient earth-as-egg analogy, however, is a ºeeting conceit in a protracted discourse about catastrophic alterations to land levels in prehistoric times. He never invests the yolky interior with an animating principle: its gluti- nous mass cannot host life. Similarly, the “Burrows, and Channels, and Clefts, and Caverns” described in Thomas Burnet’s Sacred Theory of the Earth (1681), although testifying to “the unsoundness and hollowness of the Earth in the inward recesses of it,” are lifeless and uninhabitable, never having “had the comfort of one beam of light since the great fall of the Earth” (Burnet 1681, pp. 6–7). The lava–ªlled chambers and caverns of Athanasius Kircher’s percolating globe in his Mundus Subterraneus (1665) are likewise inhospitable. Kircher’s ash-spewing mountains, fed by a laby- rinth of sinuous, magma–bearing conduits and ignited antechambers, present an awe-inspiring vision of a honeycombed and excretory interior. But this ornately conceived volcanic world is anything but livable. In contrast Halley, who would have been familiar with these models, was unique for grounding his theory of a multi-sphered hollow earth in Newtonian physics and for making it habitable. I therefore share with Duane Grifªn the opinion that, in proposing a hollow earth as a way of in- terpreting otherwise inexplicable ºuctuations of the magnetic needle, “Halley invented the world anew” (Griffen 2012, p. 6). Halley’s hypothesis, “our ªrst scientiªc theory of the hollow earth” (Standish 2006, p. 12), was not an eccentric anomaly in an otherwise illustrious career, but was a rational argument, based on Newtonian physics, for a parallel world that quickly found transatlantic adherents, enjoyed signiªcant posthumous prestige in both scientiªc and amateur communities, and answered some pressing questions that had immediate import for European explorers in the early age of Empire. It served as a practical if also deliberately specula- tive response to geological and astronomical conundrums in an era that did not recognize any fundamental hostility between the employment of new empirical methods and a ªrm belief in supernatural design. We may take Halley’s proposition seriously by recognizing the particular discursive context that produced it as a meaningful response to urgent questions, while also enjoying the author’s self-deprecation and beguiling style. By attending to the epistemological organization of his thought,

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allowing for the intrusion of calculated guesswork where empirical knowledge remains elusive, we may learn to appreciate in Halley’s “Account” what Stephen Jay Gould has found admirable in the works of Kircher— “not so much [. . .] the power of his insights and assertions, but [. . .] the quality of his doubts, and the willingness to grope and struggle with mate- rial he understood only poorly” (Gould 2004, p. 235). Secondly, Halley’s hypothesis was to be invoked, directly and implic- itly, in subsequent philosophies of a habitable inner globe9 and, as suggested by my earlier citation of the anonymous Voyage, in a diverse body of hollow earth fantasies and utopias. The latter originated in mid- eighteenth century Europe, reached a crescendo in late nineteenth century America, and remains a robust science ªction sub-genre of the present day.10 “As hollow earth theory disappeared from science,” Daniel Cohen has noted, it “was adopted by writers of imaginative ªction” (Cohen 1972, p. 63). Halley’s hollow–earth theory, the ªrst to propose a complexly structured chthonic realm suitable for human occupancy and to back itself up with hard science in the form of Newton’s Principia, therefore enjoyed a rich ideological and literary afterlife. It was one of those “wrong ideas” or implausible propositions that had an obdurate cultural and literary endur- ance despite its now evident wrongness. Gradually subjugated by the scientiªc discourse that birthed it, the hollow–earth idea found a lasting home in prose ªction. Cotton Mather’s enthusiastic introduction of Halley’s theory to an American audience in the Christian Philosopher (1721)—“why may we not [. . .] suppose four Ninths of our Globe to be Cavity? Mr. Halley allows there may be Inhabitants of the lower Story, and many ways of producing Light for them” (Mather 1721, p. 110)—might be viewed as a late “scientiªc” defense of the “Account,” after which the

9. The major defenses of hollow earth theory come from America. Aside from McBride’s reverential Symmes’s Theory . . . they include an identically-titled book by Symmes’ eldest son, Americus (1878), a vigorous defense of the elder Symmes’ theories; W. F. Lyon’s The Hollow Globe (1871); Cyrus Reed Teed’s The Cellular Cosmogony, or, the Earth a Concave Sphere (1898); William Reed’s The Phantom of the Poles (1906); Marshall B. Gardner’s A Journey to the Earth’s Interior, or, Have the Poles Really Been Discovered (1913); and Raymond Bernard’s The Hollow Earth: The Greatest Discovery in History (1963). 10. Along with the Voyage to the World in the Centre of the Earth, better-known examples published in the 1700s are Ludwig Holberg’s A Journey to the World Underground (1742) and Jacques Casanova de Seingalt’s Casanova’s ‘Icosameron’ or the Story of [...] the Interior of our Globe (1788). Some better known titles of the late-nineteenth and early-twentieth centuries are Mary E. Bradley Lane’s Mizora: A World of Women (1881), John Uri Lloyd’s Etidorpha (1895), and Willis George Emerson’s The Smoky God (1908). For a useful but incomplete annotated bibliography of hollow earth novels of the latter period, see the appro- priate entry in Everett F. Bleiler’s Science Fiction: The Early Years (1990). Recent examples of the sub-genre include Rudy Rucker’s The Hollow Earth: The Narrative of Mason Algiers Reynolds of Virginia (1990) and Max McCoy’s Indiana Jones and the Hollow Earth (1997).

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hollow–earth idea was increasingly relegated to the purview of utopian novelists and fringe enthusiasts. Coupling indelibly the distinguished reputation of a great scientiªc mind with a seemingly fantastic geological idea, Mather’s eulogy, like Dahl’s portrait, played an initiatory role in the hollow earth’s literary adoption. These eulogies reconstructed the central novum of later hollow–earth ªction: the scientiªcally plausible inner space that served as a foil to the real, historical world of the writer, and hence as a setting for contrast and allegory.

3. Halley’s Argument: Why a Hollow Earth Made Sense Halley’s discourse opens with the central premise already alluded to: that a “theory of the Variation of the Magnetical Compass” must suppose “the Globe of the Earth [...] to be one great Magnet, having four Magnetical Poles or Points of Attraction.” Only a comprehension of the earth as a quaternary-poled, “whole magnetical system” can “render a tollerable account of the observed Variations” of the compass that Halley outlines in his opening pages, where he notes that between the years 1550 and 1692, in places as diverse as Paris, Cap d’Agulhas, St. Helena, and Cape Com- orine, numerous trustworthy observers recorded shifts in magnetical read- ings so substantial that in London alone “in 112 years the direction of the Needle has changed no less than 17 degrees” (Halley 1692, p. 565). The cause (or causes) of magnetical variation are a riddle the difªculties of which “had wholly made [Halley] despond,” to the point that he “had long since given over an inquiry [he] had so little hopes of; when in acci- dental discourse, and least expecting it, [he] stumbled upon the following Hypothesis”—a redress, Halley acknowledges, apparently so “Extravagant or Romantick” that he must beg his reader “to suspend his censure, till he have considered the force and number of the many Arguments which con- cur to make good so new and so bold a Supposition” (Halley 1692, pp. 564–65). Halley’s quandary, then, is “that the Direction of the [magnetical] Nee- dle is in no place ªxt and constant.” This lack of ªxity and constancy leads him to argue that the earth has more than two poles: it has at least four, the North and South Poles moving at a different rotational speed than the second pair of poles, suggesting that “the whole magnetical system is by one or perhaps more Motions translated” (Halley 1692, pp. 566, 567). Where is the second set of poles located? How do they operate reciprocally with the North and South Poles to inºuence the magnetical compass in such extraordinary ways? There is, Halley asserts, “only [one] way to render this Motion intelligible and possible”: there is a “moving thing” internal to the earth in which the subsidiary poles are rooted. This “thing” we must “suppose [. . .] to turn about the Centre of the Globe, having its

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Centre of Gravity ªxt and immoveable in the same common Centre of the Earth: And there is yet required that this moving internal Substance be loose and detached from the external parts of the Earth, whereon we live” (Halley 1692, p. 567). In other words, the earth is structured as a globe- within-a-globe, both moving together in the same diurnal rotation but at slightly different velocities. Halley elaborates upon this point by intro- ducing the crucial notion of a liquid or hydraulic substance that separates the spheres, a kind of lubricating matter that enables their slightly different axial motions: So then the External Parts of the Globe may well be reckoned as the Shell, and the Internal as a Nucleus or inner Globe included within ours, with a ºuid medium between. Which having the same common Centre and Axis of diurnal Rotation, may turn about with our Earth each 24 hours; only this outer Sphere having its turbinat- ing Motion some small matter either swifter or slower than the internal Ball. (Halley 1692, p. 568) Halley has established a basic model for the multi-sphered earth, a proposition vindicated by its singular capacity to explain the capriciousness of the magnetical compass. “‘Tis plain,” Halley summarizes, “that the ªxt Poles are the Poles of this External Shell or Cortex of the Earth, and the other two Poles of a Magnetical Nucleus included and moveable within the other.” For those of his listeners who might quibble with the details of his model at this incomplete stage of its elaboration, Halley preempts ex- temporaneous criticism of “this abstruse Theory” by pointing out that “the nice Determination of this and of several other particulars in the Magnetick System is reserved for remote Posterity; all that we can hope to do is to leave behind us Observations that may be conªded in, and to propose Hypotheses which after Ages may examine, amend or refute” (Halley 1692, p. 571)—a refreshing and savvy admission that the temporal limi- tations of scientiªc observation invariably introduce surmise and indeterminacy. But Halley appears to teeter on the brink of learned intemperance. “In order to explain the change of the Variations,” he recapitulates, “we have adventured to make the Earth hollow and to place another Globe within it: and I doubt not but this will ªnd Opposers enough” (Halley 1692, p. 572). In the vein of preemption that caused him to project into the dis- tant future responsibility for the amendment or refutation of his hypothesis, Halley outlines four possible objections to his hollow–earth theory and addresses each individually. In the process of dealing with the ªnal reser- vation, he appeals ªrst to the “Wisdom of the Creator,” the ªnal authority in all discussions of cosmic form and order, and secondly to “the excellent

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Mr. Newton,” whose Principia had appeared four years earlier—allusions suggestive of the paciªc interplay between scientiªc and religious thought still common to natural philosophy of the seventeenth century, which credited God with simultaneously contriving and adhering to those im- mutable laws of nature that modern mathematics, geometry, and mechan- ics were capable of divulging. In his tributary ode to the Principia, “On This Splendid Ornament of Our Time,” Halley himself was eloquent (if also somewhat ambivalent) in his formulation of this interplay. As W. R. Albury has shown, in the “Splendid Ornament” Halley argued “from the principles of Newton’s physics to the existence and providence of a divine Creator” (Albury 1978, p. 24), although he remained typically reticent about any allegiance to the avenging divinity cherished by Christian orthodoxy of the early eighteenth century. More accurately, Halley the reputed skeptic appeared to be emphasizing this connection in the version of the poem that prefaced the second edition (1713) of Newton’s work, which had been purged by its editor, Richard Bentley, of theologically objectionable views and in the process “converted [. . .] from a Lucretian poem into a ªt vehicle for physico-theology” (Albury 1978, p. 40). The result of this unsolicited edi- torializing was an opening sestet that exhorted Newton’s admirers to Behold the pattern of the heavens, and the balances of the divine structure; Behold Jove’s calculation and the laws That the creator of all things, while he was setting the beginnings of the world, would not violate; Behold the foundations he gave to his works. Heaven has been conquered and its innermost secrets are revealed; The force that turns the outermost orbs around is no longer hidden. The pliant facility with which Halley’s scientiªc method ªnds its adden- dum in religious teleology is worth noting. Certainly, the “creator of all things” invoked in the poem’s third line comes across more as a “Platonic demiurge” (Albury 1978, p. 37) than the omnipotent shaper of Genesis. Yet the complementary relation between “divine structure” or the evi- dences of design and the scientiªc investigation capable of discovering its “laws” and “innermost secrets” is clearly established. This concept of a transcendentally ordered utility of structure, we have already seen, was to reappear as a central mythos in holow–earth thought and ªction of the eighteenth and nineteenth centuries. Halley’s inventory of potential dissent to his holow–earth theory is itself economical and fascinating for the way it reveals some of the main currents of geological debate at this historical moment:

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I know ’twill be objected, [ªrst] That there is no Instance in Nature of the like thing; [second] That if there was such a middle Globe it would not keep its place in the Centre, but be apt to deviate there- from, and might possibly chock against the concave Shell, to the ruine or at least endammaging thereof; [third] That the Water of the Sea would perpetually leak through, unless we suppose the Cav- ity full of Water; [fourth] That were it possible yet it does not appear of what use such an inward Sphere can be of, being shut up in eternal Darkness, and therefore unªt for the Production of Animals or Plants; with many more Objections, according to the Fate of all such new Propositions. (Halley 1692, p. 572)

To the ªrst objection—that nature provides no other example of a hollow globe or planet—Halley replies, “the Ring environing the Globe of Saturn is a notable Instance of this kind, as having the same common Centre, and moving along with the Planet, without sensibly approaching him on one side more than the other. And if this Ring were turned on one of its Diameters, it would then describe such a concave Sphere as I suppose our External one to be” (Halley 1692, p. 572). In this analogy Halley turns to the comparatively recent observations of Saturn made by Christiaan Huygens and Giovanni Cassini between the 1650s and 1670s, which de- termined that the sixth planet is surrounded by a thin, ºat ring composed of multiple smaller rings separated by gaps. The modern telescope, its magnifying capacity improved exponentially in the decades since Galileo’s groundbreaking observations of 1609–10, provided Halley with the evidence his esoteric theory required: that other solar bodies indeed furnish a structural and now-dramatically visible model of, and hence an important precedent for, a holow–earth. Halley returns sanguinely to the example of Saturn to rebut the second criticism, that an inner globe “would not keep its place,” but bump up against the earth’s outer shell with catastrophic results. “Since [Saturn’s] Ring in any position given,” he argues,

would in the same manner keep the Centre of Saturn in its own, it follows that such a concave Sphere may move with another included in it, having the same common Centre. Nor can it well be supposed otherwise, considering the Nature of Gravity, for should these Globes be adjusted once to the same common Centre, the Gravity of the parts of the Concave would press equally towards the Centre of the inner Ball, which Equality must necessarily continue till some external force disturb it, which is not easie to imagine in our case. (Halley 1692, p. 573)

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Saturn’s convenience as a point of reference in this argument by analogy confronts Halley with the inevitable question of gravity, which he turns to his advantage. Gravitational theory was to remain an open ªeld for speculation and discovery well into the nineteenth century, when James Clerk Maxwell and Henri Poincaré focused their attention on such matters as electromagnetic and gravitational interactions. Here, Halley applies New- ton’s law of universal gravitation mutually to earth’s subterranean regions and to Saturn, a planet that appeared to be durably positioned within rings which he, like other astronomers of the time, believed to be composed of solid rather than particulate matter. The point to be emphasized once again is that Halley’s theory ªnds its defense in new technologies, at a particular historical moment when the physical details of a heliocentric universe were being telescopically discovered and interpreted in an increasingly scientistic process of dismissal of the geocentric episteme. Hal- ley’s advanced comprehension of the workings of the Copernican universe and of Newtonian gravitational theory rendered efªcacious the type of comparative method he employs, wherein Saturn functions as a credible model for a holow–earth whose inner sphere or spheres exist in an exquisitely balanced “equality” of magnetic attraction with an outer shell. Halley takes care of the third objection—that water from oceans and seas would inevitably leak through to earth’s hollow center to who knows what cataclysmic effect—with winsome facility: “when we consider how tightly great Beds of Chalk or Clay, and much more Stone do hold water, and even Caves arch’d with Sand” (Halley 1692, p. 573), Halley reasons, we can dismiss this concern without further difªculty. Which leaves the fourth and, for Halley and his contemporaries, the most consequential of concerns: what ultimate purpose or use can “such an inward sphere” have? What value, what beneªt or avail could a holow– earth have for terrestrial inhabitants who are insensible of it and whose fe- licity and health appear to be wholly independent of it? In short, for what or who was it designed? The problem of utility would have been a conten- tious issue that Halley had to address in outlining his hypothesis: “In Halley’s day, a full century before Kant would caution against teleology as a constitutive principle in his Critique of Judgment, the question of utility was a signiªcant issue that could not be ignored” (Griffen 2012, p. 11). As the corporeal expression of divine intelligence, earth testiªes in every detail of its structure to the expedience of providential design: the Creator would not mold a planetary habitation that wastes space. If, then, only a holow–earth can explain ºuctuations of the magnetic needle, its very existence is the necessary expression of providential thrift, of creation’s rational adherence to the precept of use-value. Halley speaks at some length about the numinous instrumentality of inner space. In the

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process, he makes a ªnal riposte to the question of watery leakage and cites a calculation about lunar relative density in Newton’s Principia, a mathematical adoption that has been interpreted by some as an untoward lapse of interrogative rigor:11

No Man can doubt but the Wisdom of the Creator has provided for the Macrocosm by many more ways than I can either imagine or ex- press, especially since we see the admirable and innumerable Con- trivances wherewith each worthless Individual is furnisht both to defend itself and propagate its Species. What Curiosity in the Structure, what Accuracy in the Mixture and Composition of the parts ought not we to expect in the Fabrick of this Globe [. . .] and can we then think it a hard supposition that the Internal parts of this Bubble of Earth should be replete with such Saline and Vitriolick Particles as may contribute to petrifaction, and dispose the transuding Water to shoot and coagulate into Stone, so as con- tinually to fortiªe, and if need were to consolidate any breach or ºaw in the Concave Surface of the Shell [. . .]. Another Argument favouring this Hypothesis is drawn from a Proposition of [. . .] Mr. Newton, where he determines the force wherewith the Moon moves the Sea in producing the Tides [. . .]. Now if the Moon be more solid than the Earth as 9 to 5, why may we not reasonably suppose the Moon, being a small Body and a Sec- ondary Planet, to be solid Earth, Water, and Stone, and this Globe to consist of the same Materials, only four ninths thereof to be Cav- ity, within and between the internal Spheres: which I would render not improbable. (Halley 1692, pp. 574–575)

In the latter appeal, Halley refers to Newton’s discussion of solar and lunar inºuences on terrestrial tides, which led him to calculate that the density of the moon to the earth is in a ratio of nine to ªve: “Therefore the body of the moon is denser and more earthy than our earth” (Newton [1697] 1999, p. 878). Halley applies his own version of this computation to his hypothesis about the earth’s structure as further demonstration of earth’s cavernous anatomy. Our planet’s lesser mass, as demonstrated in Newton’s discussion of tidal movements, can be explained by its hollow interior. Although Newton was later to revise his estimation, substantially reduc- ing the difference between lunar and terrestrial densities as eleven to 11. See Kollerstrom (1992): “Halley had been much involved with the production of the Principia, and it now seemed to provide him with a key. Its estimate of Earth/Moon mass ratio suggested to him that the Earth was hollow. How else could that ratio be explained?” (p. 3).

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nine,12 Halley could have applied this modiªed calculation without loss of argumentative vigor or credibility. His casual solicitation of such numeri- cal proofs is a rhetorical rather than a strictly mathematical maneuver. Given the suppositional nature of his discourse, Halley’s earth could as “reasonably” be estimated at nine elevenths cavity as at “only four ninths”—one ratio is not inherently more probable than the other, so long as Newton’s illustrious name is attached to it. Halley returns late in the “Account” to the question of utility, an inquiry that leads him to the most remarkable and, for future holow–earth novelists, the most fruitful of propositions—that the inner earth may be capable of supporting life, and that its structure may be as complex as that shown in the appended diagram (Figure 2). Such a fantastic suggestion can be entertained if we inquire further into the nature of the ºuid or ether that separates the inner globe (or, now, globes) from the outer, an as yet unknown, magnetically charged medium that may well produce its own vivifying light. Or, perhaps an inner sun, a “peculiar luminary,” sheds its light at the very core of the earth, either in a state of centroidal inertia or in an orbital path within the globe’s shell. Our ignorance on these matters, Halley argues, as on many questions of divine creation, does not pre- clude the possibility of their existence: To those that shall enquire of what use these included Globes can be, it must be allowed, that they can be of very little service to the Inhabitants of this outward World, nor can the Sun be serviceable to them, either with his Light or Heat. But since it is now taken for granted that the Earth is one of the Planets, and they all are with reason supposed Habitable, though we are not able to deªne by what sort of Animals; and since we see all parts of the Creation abound with Animate Beings [. . .] all whose ways of living would be to us incredible did not daily Experience teach us. Why then should we think it strange that the prodigious Mass of Matter, whereof this Globe does consist, should be capable of some other improvement than barely to serve to support its Surface? Why may not we rather suppose that the exceeding small quantity of solid Matter in respect of the ºuid Ether, is so disposed by the Almighty Wisdom as to yield as great a Surface for the use of living Creatures as can consist with the conveniency and security of the whole? [. . .] But still it will be said that without Light there can be no living, and therefore all this apparatus of our inward Globes must be use- less: to this I answer that there are many ways of producing Light 12. In Book 3, Proposition 37, Corollary 3 of the second and third editions Newton corrected the earlier calculation “as 4,891 to 4,000, or 11 to 9.”

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which we are wholly ignorant of; the Medium itself may be always luminous after the manner of our Ignes fatui. The Concave Arches may in several places shine with such a substance as invests the Sur- face of the Sun; nor can we, without a boldness unbecoming a Phi- losopher, adventure to assert the impossibility of peculiar Lumi- naries below, of which we have no sort of Idea. (Halley 1692, pp. 576–77) Halley’s casual reference to the idea of habitable planets is not surprising. The belief that other planets were “worlds” similar to earth was wide- spread at the time of his “Account,” a persuasion that combined Coperni- cus’ mid-sixteenth century theories about planetary orbit with Galileo’s telescopic observations of the moon’s mountainous surface, which allowed for subsequent speculation about the structure of planets as potentially life-supporting spheres. Indeed, to be rather obvious, Halley’s “Account” is very much of its historical moment, symptomatic, as already suggested, of the convulsive seventeenth century shift between old and new world views that Alexandre Koyré so eloquently delineated more than ªfty years ago. Halley’s hypothesis is both a consequence of and a reaction to the rev- olution in cosmological thought that took the form of “two fundamental and closely connected actions [. . .] the destruction of the cosmos and the geometrization of space, that is, the substitution for the conception of the world as a ªnite and well-ordered whole, in which the spatial structure embodied a hierarchy of perfection and value, that of an indeªnite or even inªnite universe no longer united by natural subordination, but uniªed only by the identity of its ultimate and basic components and laws” (Koyré 1957, p. vi). Halley’s investiture of a hollow globe with animating light granted an implicit mandate to superterranean explorers to discover and colonize earth’s capacious hollow interior, a “great surface” divinely contrived to accommodate a surplus of “living Creatures.”

4. Halley’s Diagram Explained Halley terminates his “Account” with a brief exposition on the schema displayed in Figure 2. “I have adventured to adjoyn the following Scheme,” he writes, wherein the Earth is represented by the outward Circle, and the three inward Circles are made nearly proportionable to the Magni- tudes of the Planets Venus, Mars and Mercury. [. . .] The Concave of each Arch, which is shaded differently from the rest, I suppose to be made up of Magnetical Matter; and the whole to turn about the same common Axis p. p. only with this difference, that the Outer Sphere still moves somewhat faster than the Inner. [. . .] Thus I

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have shewed a possibility of a much more ample Creation, than has hitherto been imagined; and if this seem strange to those that are unacquainted with the Magnetical System, it is hoped that all such will endeavor ªrst to inform themselves of the Matter of Fact and then try if they can ªnd out a more simple Hypothesis, at least a less absurd, even in their own Opinions. And whereas I have adventured to make these Subterraneous Orbs capable of being inhabited, ‘twas done designedly for the sake of those who will be apt to ask cui bono, and with whom Arguments drawn from Final Causes pre- vail much. (Halley 1692, pp. 576–577) Halley would have felt compelled to allude to God’s inªnite grace in creating a multi-sphered world at a moment when his application for the vacant Savilian Chair of Astronomy at Oxford was being strongly con- tested, especially by ªrst Astronomer Royal John Flamsteed. As demonstrated by Bentley’s revisions to the Principia ode, Halley’s reputation as a skeptic made him vulnerable to various forms of censorship. His unortho- dox views on the matter of terrestrial inªnity, at a time when “the belief in the eternity of the world was seen as genuinely heretical” (Schaffer 1977, p. 18), made Halley a suspect candidate in the eyes of the Chair’s electors—the “Final Causes” crowd, perhaps. Even Newton, under pro- found obligation to Halley for engaging a printer and supervising the publication of the Principia, did not support Halley’s bid for the chair, which went instead to the Scottish mathematician David Gregory.13 Halley’s radical ampliªcation of God-given, terrestrial living-space in his proposition that no fewer than three inner spheres inhabit the holow– earth is, at least in part, an inspired gesture of conciliation. Nevertheless, Halley did not abandon the idea. Nor did the Philosophi- cal Transactions give up on the theory, reprinting it in abridged form in 1731, 1749, and 1819, as well as in Volume 1 of the Miscellanea Curiosa, a collection of the Society’s “most valuable” lectures. When in 1716 Halley was approached by the Society to offer an explanation of the “unusual Lights which have of late appeared in the Heavens,” he made so bold as to return to his original hollow-earth hypothesis, suggesting that the “subtile Matter” of the aurora borealis was capable of “pervading the Pores of the Earth” from its subterranean source: Lastly I beg leave on this Occasion to mention what, near 25 Years since, I publish’d in No. 95 of these Transactions, viz. That supposed the Earth to be concave, with a lesser Globe included, in order to 13. On Halley’s failure to attain the Savilian Chair in 1691, see also Richard S. Westfall and Gerald Funk (1990), pp. 3–13.

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make that inner Globe capable of being inhabited, there might not improbably be contained some luminous Medium between the Balls, so as to make a perpetual Day below. [. . .] And if such a Me- dium should be thus inclosed within us; what should hinder but we may be allowed to suppose that some parts of this lucid Substance may, on very rare and extraordinary Occasions, transude through and penetrate the Cortex of our Earth? (Halley 1716, p. 428)

Halley concluded this particular essay by asking his readers to “lay no more stress upon this Conceit than it will bear,” encouraging them to at- tend to the ªguralism of his language and intimating that this account of the source of the northern lights was as much a dexterous thought experi- ment as it was a solemn proposal. Halley’s usage here is reminiscent of the ambiguities and confessed irresolutions of his earlier “Account,” in which doubt is graciously conceded to be irreducible, an inherent part of the scientiªc endeavor. Yet when Halley sat for Dahl twenty years later, he posed with a diagram of the holow–earth. The venerable astronomer continued to cherish the nested globe hypothesis as a practical explanation for what remained in his dotage a fundamental mystery, the question of magnetic variation. Halley’s holow–earth proposal was certainly a heuristic exercise, a specula- tive formulation and guide for further investigation rather than a statement of tested conviction. But it is precisely Halley’s provisional disposi- tion in the “Account” that makes of this address something more than a nimble intellectual game. Magnetic variation had seriously dangerous consequences for seventeenth-century mariners; the urgency of the problem did not incite mere ºights of fancy by way of response, although the occasional rhetorical caprice lent persuasive charm to Halley’s lecture. Pro- viding his learned audience was unable to “ªnd out a more simple Hy- pothesis, at least a less absurd” one than his own, Halley proposed his complex model as the most pragmatic and hence judicious response to a conundrum that remained otherwise intractable to diagnoses sacred or scientiªc. Long after his death, Halley’s theory continued to attract novelists in the utopian tradition who presented a habitable interior as the ªnal answer to questions about terrestrial structure. Works of holow–earth ªction occasionally returned to Halley’s conception of a “much more ample Cre- ation” as a way of explaining the existence of subterranean realms, geogra- phies providentially construed to host alternative civilizations. Symzonia: A Voyage of Discovery (1820) speaks compellingly to this observation. A novel widely celebrated as “the ªrst American work of utopian ªction” (Griffen 2004, p. 393), Symzonia provides a culminating statement on the

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evolution and reªnement of hollow–earth theory in Halley’s wake—a history of adaptations that often rivaled the original hypothesis for imaginative extravagance. Symzonia’s pseudonymous author-narrator, Captain Adam Seaborn, is motivated by a desire to locate in nature’s physical ar- rangements evidence of deeper purpose and meaning. “I had undertaken this perilous voyage,” Seaborn explains to his alien inquisitors shortly after ªrst contact with the “Internals,” only to ascertain whether the body of this huge globe were an use- less waste of sand and stones, contrary to the economy usually displayed in the works of Providence, or, according to the sublime conceptions of one of our Wise men, a series of concentric spheres, like a nest of boxes, inhabitable within and without, on every side, so as to accommodate the greatest possible number of intelligent beings.(Seaborn 1820, p. 143) The wise man venerated here is not, in fact, Halley, but former soldier and Missouri Indian trader John Cleves Symmes (1779–1829). In his preface, Seaborn credits Symmes with supplying the “lights and facilities” for his romance, particularly its subterranean setting. Symmes never published a full account of his decidedly Halley-esque cosmogony, which he introduced to the world in 1818 with a widely-disseminated circular announc- ing that “the earth is hollow, and habitable within; containing a number of solid concentrick spheres, one within the other, and that it is open at the poles” (Symmes 1818, n. p.). He instead devoted his energies to the public lecture circuit, relentlessly promoting his conviction that these massive polar openings (the much-derided “Symmes’s Holes”) would provide their discoverers access to a well-stocked and capacious inner world. It was left to Symmes’s devoted follower, James McBride, to make ex- plicit the connection between his mentor’s philosophy and Halley’s hollow–earth hypothesis, in the process appealing to divine economy as an afªdavit for the idea’s soundness. In his treatise on Symmes’s Theory of Con- centric Spheres (1826), McBride praised the “celebrated Dr. Halley” for having “advanced a novel hypothesis” that Symmes brought to its splendid conclusion with his groundbreaking “idea of Polar Openings” (McBride 1826, pp. 131–132). Taking it “for granted, that there is a God, and that he is the ªrst cause of all things,” McBride arrived at “the opinion, that a construction of all the orbs in creation, on a plan corresponding with Symmes’s theory, would display the highest possible degree of perfection, wisdom, and goodness—the most perfect system of creative economy” (McBride 1826, p. 56). The subterranean kingdom of Symzonia represents this impeccable system. Its “perfected democracy ruled by the Good, the Wise, and the

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Useful” (Bailey 1965, n.p.) is a social and political microcosm of the hollow sphere in which it is housed, an immaculately conceived resolution to the “vexations and anxieties” of modern New York that Seaborn ºees in the novel’s opening scene (Seaborn 1820, p. 22). Seaborn eventually takes advantage of the southern Symmes’s Hole, passing through the great por- tal in his quest “to open an intercourse with a new world and with an unknown people; to unfold to the vain mortals of the external world new causes for admiration at the inªnite diversity and excellence of the works of an inscrutable Deity” (Seaborn 1820, p. 96). Seaborn’s journey thus re- iterates, albeit in an innovative narrative form, the intellectual exercise Halley undertook in his 1692 “Account.” Symzonia testiªes to the unºag- ging energy of Halley’s hypothesis for a new era in the New World. The “prodigious Mass of Matter, whereof this Globe does consist” may indeed be “capable of some other improvement than barely to serve to support its Surface.”

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