66 EAETHQUAKES. 



3. For transverse vibrations. 



If we assume that the vertical vibrations are a 

 component of the transverse motions we see the 

 same law as before — namely, that the nearer we 

 are to the origin of the disturbance the greater 

 is the speed with which that disturbance is pro- 

 pagated. 



It will be observed that the chief law here enunciated 

 respecting the decrease in speed of earth vibrations is the 

 same as that pointed out by General Abbot, from which it 

 only differs by its being in all cases proved without the 

 introduction of personal errors, for the same explosion, 

 along the same line of ground and for different kinds of 

 vibrations. 



