"The propagation of elastic waves in a homogeneous solid is governed by a hyperbolic system of three linear second-order partial differential equations with constant coefficients. When the solid is also isotropic, the form of these equations is well known and provides the foundation of the conventional theory of elasticity . The explicit solution of the initial value, or Cauchy, problem for the isotropic case was found by Poisson, and in a different way by Stokes . If the initial disturbance is sharp and concentrated, the resulting disturbance at a field point will consist of an initial sharp pressure wave, a continuous wave for a certain period, and a final sharp shear wave. The disturbance then ceases."

“The magnitude of Fundy tides may be seen as having been reached by a balance between a dissipative mechanism, with assumed quadratic frictional forces, and an energy imparting mechanism in the deep ocean where work done by the tide raising force is proportional to distance travelled and hence to the first power of amplitude. Further, it now appears that the second and third North Atlantic modes are those primarily stimulated by the Fundian resonance. To represent these processes within one model both the continental shelf shallows and oceanic areas must be included, as well as their zone of interaction across the continental shelf.”

“The theory of harmonic forms in Riemannian manifolds may be regarded as a generalization of potential theory. It is therefore natural that the boundary value problems of this theory which generalize the classical Dirichlet and Neumann problems should play an important role in the theory.”