THE EARTH. 105 



Naples, after having escaped a thousand dangers 

 both at sea and land." 



The reader, I hope, will excuse me for this long 

 translation from a favourite writer, and that the 

 sooner, as it contains some particulars relative to 

 earthquakes not to be found elsewhere. From 

 the whole of these accounts we may gather, that 

 the most concomitant circumstances are these : 



A rumbling sound before the earthquake. This 

 proceeds from the air, or fire, or both, forcing 

 their way through the chasms of the earth, and 

 endeavouring to get free, which is also heard in 

 volcanoes. 



A violent agitation, or heaving of the sea, some- 

 times before and sometimes after that at land. 

 This agitation is only a similar effect produced on 

 the waters with that at land, and may be called, 

 for the sake of perspicuity, a seaquake ; and this 

 also is produced by volcanoes. 



A spouting up of waters to great heights. It 

 is not easy to describe the manner in which this 

 is performed ; but volcanoes also perform the 

 same, Vesuvius being known frequently to eject 

 a vast body of water. 



A rocking of the earth to and fro, and some- 

 times a perpendicular bouncing, if it may be so 

 called, of the same. This difference chiefly arises 

 from the situation of the place with respect to the 

 subterranean fire. Directly under, it lifts ; at a 

 farther distance, it rocks. 



Some earthquakes seem to travel onward, and 

 are felt in different countries at different hours the 

 same day. This arises from the great shock being 



