New dynamical wave-theory of the tides : discovery of the physical cause of the variation of latitude, with calculation of the period and amplitude of the polar motion, from the observed oscillations of the unsymmetrically situated ocean hemisphere, including a revised cotidal map of the oceans, now shown to be oscillating in synchronous world-waves coperiodic with the disturbing forces, Laplace's principle, together with an investigation of other laws of the motion of the sea hitherto unknown, and an improved method for calculating the rigidity of the earth.