Mr. Adams has asked me to present this subject, not because I have made any important new contributions to it, but because I recently compressed what we know of the interior of the Earth into ten one‐hour lectures, which material was then further abstracted into a one‐hour lecture at another institution. It is only one additional step in high‐pressure technique, with which Mr. Adams is so familiar, to compress the one‐hour lecture into ten minutes.one‐hour lecture into ten minutes. The title says “seismic waves.” I would broaden it to “elastic waves,” for the earthquakes are not essential to this branch of the science of the Earth's interior structure, a science that I have ventured to call geo‐taxology. Earthquakes are only a convenient means, though not a very satisfactory one, for supplying elastic waves. Future progress in the science will undoubtedly see an increasing use of artificial and therefore controllable waves, such as may be produced by an explosion or by the f