Cosmos, Vol. 4

the molten parts of the interior—which, despite the pressure they endure, remain easily moved—undergo a change of position within the masses, even modifying the geometric surface in the curvature of the meridians and parallels across small areas after very long periods of time; likewise, the physical surface in its oceanic region is subject to a periodic change of position of the masses through the ebb and flow of the tide local depression and swelling of the liquid. The smallness of the gravitational effect in the continental regions can hide a very gradual change from actual observation; and according to Bessel's Friedrich Wilhelm Bessel (1784–1846), a German astronomer who calculated the Earth's dimensions calculation, in order to increase the latitude of a place by only 1", a change of position of a mass in the interior of the Earth must be assumed whose weight—setting its density equal to the mean density of the Earth—is that of 114 geographical cubic miles⁵. However strikingly large this volume of the shifting, moving mass appears to us when we compare it with the volume of Mont Blanc, Chimborazo, or Kanchenjunga; the astonishment at the magnitude of the phenomenon soon fades when one remembers that the Earth's spheroid comprises over 2,650 million such cubic miles.

The problem of the figure of the Earth, the connection of which with the geological question regarding the former liquid state of planetary rotating bodies was already recognized in the great era⁶ of Newton, Huygens, and Hooke, has been attempted to be solved with varying success in three ways: by geodetic-astronomical degree measurement, by pendulum experiments, and by irregularities in the longitude and latitude of the moon. The first