Symmes, however, was not the first to argue that the Earth was hollow; nor is Symzonia the first novel set in a hollow earth. There are of course numerous narratives - dating back to Greek and Roman texts - of descents into the underworld, but hypotheses about vast channels or chasms inside the Earth appear to be a much more recent idea advanced by some European thinkers in the 17th and 18th centuries as an explanation of volcanoes, whirlpools and the like. This period is filled with a variety of now discarded cosmological hypotheses, many inspired by the attempt to reconcile scriptural accounts of Creation with scientific observation: hypotheses about the movement of the sun, the earth and the stars, about the universality of the great Flood, about creation and the origins of life, and about the earth's own formation. Among the proponents of now abandoned theories about the composition of our planet was Edmond Halley (better known for the comet which bears his name), who proposed (in a paper explaining the movement of the magnetic poles published in the Philosophical Transactions of the Royal Society in 1692) that the earth was hollow: "that the seemingly solid earth is actually a shell about 500 miles thick containing three smaller concentric spheres... each sphere separated from the others by about 500 miles of atmosphere."