Symmes's Theory of Concentric Spheres. James McBride

he arrived at the ninetieth degree; and by proceeding south, in the same direction, he would arrive at the coast of Siberia, without going far into the concavity of the sphere, and without knowing that he had been within the verge. Should such a journey be effected, it would appear to confirm the old theory of the form of the earth, and put the subject at rest; although pursuing the needle might have directed the traveller into the interior, and enabled him to discover those fine countries which Captain Symmes alleges to exist there.

      Each of the spheres composing the earth, as well as those constituting the other planets throughout the universe, is believed to be habitable both on the inner and outer surface; and lighted and warmed according to those general laws which communicate light and heat to every part of the universe. The light may not, indeed, be so bright, nor the heat so intense, as is indicated in high northern latitudes (about where the verge is supposed to commence) by the paleness of the sun, and darkness of the sky; facts, which various navigators who have visited those regions confirm; yet they are no doubt sufficiently lighted and warmed to promote the propagation and support of animal and vegetable life.

      The different spheres constituting our planet, and the other orbs in creation, most probably do not revolve on axes, parallel to each other, nor perform their revolutions in the same periods of time; as is indicated by the spots on the belts of Jupiter, which move faster on one belt than another.

      The atmosphere surrounding the sphere is probably more dense on the interior than the exterior surface, the increased pressure of which must increase the force of gravity; as the power of gravity must increase in proportion as we approach nearer the poles.—Clouds formed in the atmosphere of the convexity of the sphere, probably float in through the polar openings, and visit the interior, in the form of rain and snow. And 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, thus performing the circuit of the sphere; without which supposition, it would be difficult to account for the long continued winds which, at certain seasons, are known to blow constantly for several months, more or less obliquely to and from the poles.

      The disciples of Symmes believe that each sphere has a cavity, or mid-plane space near the centre of the matter composing it, filled with a very light, subtile, elastic substance, partaking somewhat, perhaps, of the nature of hydrogen gas; which aerial fluid is composed of molecules greatly rarified in comparison with the gravity of the extended or exposed surfaces of the sphere. This mid-plane space tends to give the sphere a degree of lightness and buoyancy. Besides this large mid-plane space, perhaps numerous other interstices exist in the sphere nearer the surface, and of more limited extent. The gas escaping from these spaces is, no doubt, the cause of earthquakes; and supply the numerous volcanoes. This gas becoming rarified and escaping, must occasion most of those great revolutions and phenomena in nature, which we know to have occurred in the geology of the earth. This aerial fluid with which the mid-plane spaces are filled, may possibly be adapted to the support of animal life; and the interior surfaces of the spheres formed by them, may abound with animals, with organs only adapted to the medium which they are destined to inhabit.

      In many parts of the unfathomable ocean there may be communications or passages from the surface of the sphere on the outer side to the surface of the inner, at least all except the great mid-plane space, through which liquid apertures, light and heat may be communicated, perhaps, to the interior surface of the sphere.