CHAPTER XIX.. Earth Tremors.

EARTH TREMORS.

Artificially produced tremors—Observations of Kater, Denman, Airy, Palmer, Paul—Natural tremors—Observations of Zöllner, M. d’Abbadie, G. H. and H. Darwin—Experiments in Japan—With seismoscopes, microphones, pendulums—Work in Italy—Bertelli, Count Malvasia, M. S. di Rossi—Instruments employed in Italy—Tromometers, microseismographs, microphones—Results obtained in Italy—In Japan—Cause of microseismic motion 306