VI PREFACE. 



quakes, it has been possible to make the description of 

 these phenomena comparatively short. 



The scheme which has been adopted will be under- 

 stood from the following table : — • 



I. Earthquakes. 



1. Introdnction. 



2. Seismometiy. 



((a) Theoretically. 



o -m ^t. 1 T»T i- (^) As deduced from experiments, 



3. Eaiihqnake Motion . . ^^^^ ^^ ^^^^^^^ ^^^^ ^^^^^^ ^^^^^, 



\ quakes. 



4. Earthquake Effects . . \^,f} ?V^'^t'r. 



^ [ (Z>) In the ocean. 



5. Determination of Earthquake origins. 



((a) In J 



6. Distribution of Earthquakes.] (*) ^^l^^^r'SIw^'ni; 



((a) In space. 



\ diurnal, &c.) 



7. Cause of Earthquakes. 



8. Earthquake prediction and warning. 



II. Earth Tremors. 



III. Earth Pulsations. 



IV. Earth Oscillations. 



In some instances the grouping of phenomena according 

 to the above scheme may be found inaccurate, as, for 

 example, in the chapters referring to the effects and causes 

 of Earthquakes. 



This arises from the fact that the relationship between 

 Earthquakes and other Earth phenomena are not well 

 understood. Thus the sudden elevation of a coast line 

 and an accompanying earthquake may be related, either 

 as effect and cause, or vice versa, or they may both be the 

 effect of a third phenomenon. 



