PEEFACE. Vll 



Much of what is said respecting Earthquake motion 

 will show how little accurate knowledge we have about 

 these disturbances. Had I been writing in England, and, 

 therefore, been in a position to make references to libraries 

 and persons who are authorities on subjects connected 

 with Seismology, the following pages might have been 

 made more complete, and inaccuracies avoided. A large 

 proportion of the material embodied in the following 

 pages is founded on experiments and observations made 

 during an eight years' residence in Japan, where I have 

 had the opportunity of recording an earthquake every 

 week. 



The writer to whom I am chiefly indebted is Mr. 

 Robert Mallet. Not being in a position to refer to 

 original memoirs, I have drawn many illustrations from 

 the works of Professor Karl Fuchs and M. S. di Rossi. 

 These, and other writers to whom reference has been 

 made, are given in an appendix. 



For seeing these pages through the press, my thanks 

 are due to Mr. Thomas Gray, who, when residing in Japan, 

 did so much for the advancement of observational Seis- 

 mology. 



For advice and assistance in devising experiments, I 

 tender my thanks to my colleagues. Professor T.Alexander, 

 Mr. T. Fujioka, and to my late colleague. Professor John 

 Perry. 



For assistance in the actual observation of Earth- 

 quakes, I have to thank my friends in various parts of 

 Japan, especially Mr. J. Bissett and Mr. T. Talbot, of 

 Yokohama. For assistance in obtaining information from 



