Hollow Earth: The Long and Curious History of Imagining Strange Lands, Fantastical Creatures, Advanced Civilizatio Read Online Free PDF Page A

his great inspiration—“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 fluid medium between.”
    Placing another sphere, with its own magnetic poles, turning slowly inside our own, solves the problem of the four magnetic poles. The disparity in rotation is slight—“in 365 Revolves the difference is scarce sensible.” But it is enough to account for the gradual westward drift found in magnetic readings.
    Alas, there will be scoffers. After urging “all Masters of Ships and Lovers of natural Truths” to continue collecting data and forward it to the Royal Society, he says, almost with a sigh, “in order to explain the change of the variations, we have adventured to make the Earth hollow and to place another Globe within it: and I doubt not but this will find Opposers enough.” He next tackles possible objections—some with more success than others. There is nothing like this in nature. The inner globe would bang against the outer. The seas would leak into it. And, given the metaphysics of the time, even if it were possible, “yet it does not appear of what use such an inward Sphere can be of, being shut up in eternal Darkness, and therefore unfit for the Production of Animals or Plants.” (Italics mine.)
    He dismisses the first objection by pointing to Saturn surrounded by its rings. The nature of gravity would keep the inner globe from “chocking” against the outer. The seas wouldn’t drain into it because, well, “the Wisdom of the Creator has provided for the Macrocosm by many more ways than I can either imagine or express.” (God still came in handy when needed.) “What Curiosity in the Structure,” he continues, “what Accuracy in the Mixture and Composition of the parts ought not we to expect in the Fabrick of this Globe?” And the very nature of “the Magnetical Matter” might help here. Invoking Newton’s Principia, he says that gravity is also such that the particles on the underside of the “Terrestrial parts of our Globe” would over time “molder away or become loose” to “fall in, and with great force descend on the Internal [sphere], unless those particles were of another sort of Matter.” And what might that be? “Why then may we not suppose these said Arches to be lined throughout with a Magnetical Matter, or rather to be one great Concave Magnet, whose two Poles are the Poles we have before observed to be fixt in the Surface of our Globe.” It’s all done by magnets! The magnetical matter would pull everything upward and patch up any holes that might form, like a puncture-proof tire.
    Again he turns to Newton, this time in regard to the relative densities of the earth and moon. Newton had calculated that “the Moon be more solid than the Earth as 9 to 5.” Since the earth consists of the same materials and is so much larger, Halley asks if it isn’t then logical to suppose “four ninths thereof to be Cavity?” As it happens, Newton’s calculation of the moon’s density was one of the few major errors in the Principia (the real ratio is 1 to 81), but no one knew that at the time.
    Now we get to the good part. What possible use might these inner spheres have?
    He first allows “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 he has answers to this objection. What follows next is a neat conflation of science and religion. He says that “it is now taken for granted that the Earth is one of the Planets”—the Copernican view of the universe—“and that they all are with reason supposed Habitable, though we are not able to define by what sort of creatures.” This too was a popular idea at the time. A book published in 1686 by French scientist Bernard le Bovier de Fontenelle, Conversations on the Plurality of Worlds, a chatty account of the latest scientific news