A systematic account of earth movements—earthquakes, tremors, pulsations, and long-period oscillations—covering seismometry, theoretical and experimental analyses of seismic motion, instruments and recording methods, observed effects on land, ocean, and buildings, and methods for locating and classifying events. The text surveys experiments with falling weights and explosives, reviews pendulum and other seismographs, examines wave propagation, intensity, duration, and radiation of disturbances, considers geographic and temporal distribution and possible causes, and addresses earthquake prediction and warning alongside practical implications for geology and engineering.