304 EAKTHQUAKES. 



last shock it is also related that all the dogs escaped from 

 the city of Talcahuano. 



Earthquake warning, — What has here been said 

 respecting the prediction of earthquakes is necessarily 

 imperfect — many of the signs which are popularly sup- 

 posed to enable persons to foretell the coming of an earth- 

 quake having already been mentioned in previous chapters. 

 That we shall yet be able to prepare ourselves against 

 the coming of earth quakes^ by the applications of laws 

 governing these disturbances, is not an unreasonable hope. 



With an electric circuit which is closed by a movement 

 of the ground, we are already in a position to warn the 

 dwellers in surrounding districts that a movement is 

 approaching. 



An earthquake which travelled at the rate of four 

 seconds to the mile might, if it were allowed to close a 

 circuit which fired a gun at a station fifteen miles distant, 

 give the inhabitants at that place a minute's warning to 

 leave their houses. The inhabitants of Australia and the 

 western shores of the Pacific might, by telegraphic com- 

 munication, receive eighteen to twenty-five hours' warn- 

 ing of the coming of destructive sea waves resulting from 

 earthquakes in South America. 



Although warnings like these might have their value, 

 that which is chiefly required is to warn the dwellers 

 at and near an earthquake centre of coming disturbances. 



What the results of the observations on earth tremors 

 will lead to is problematical. 



Should microseismic observation enable us to say when 

 and where the minute movements of the soil will reach a 

 head, a valuable contribution to the insurance of human 

 safety in earthquake regions will have been attained. 



As to whether the movements of tromometers are 

 destined to become barometric-like warnings of increased 



