262 SEE— TEMPERATURE, SECULAR COOLING | April 20, 



It is safest when it vibrates and causes a creaking in the building, and where 

 it swells and rises upwards, and settles with an alternate motion. It is also 

 harmless when the buildings coming together butt against each other in 

 opposite directions, for the motions counteract each other. A movement 

 like the rolling of waves is dangerous, or when the motion is impelled in 

 one direction. The tremors cease when the vapour bursts out; but if they 

 do not soon cease, they continue for forty days ; generally, indeed, for a 

 longer time : some have lasted even for one or two years. 



" Chap. 85 (83) — Prodigies of the Earth which have Occurred Once only. 

 " A great prodigy of the earth, which never happened more than once, 

 I have mentioned in the books of the Etruscan ceremonies, as having taken 

 place in the district of Mutina, during the consulship of Lucius Martius and 

 Sextus Julius. Two mountains rushed together, falling upon each other with 

 a very loud crash, and then receding; while in the daytime flame and smoke 

 issued from them; a great crowd of Roman knights, and families of people, 

 and travellers on the ^milian way, being spectators of it. All the farm- 

 houses were thrown down by the shock, and a great number of animals 

 that were in them were killed; it was in the year before the Social war; 

 and I am in doubt whether this event or the civil commotions were more 

 fatal to the territory of Italy. The prodigy which happened in our own age 

 was no less wonderful; in the last year of the emperor Nero, as I have re- 

 lated in my history of his times, when certain fields and olive grounds in 

 the district of Marrucinum, belonging to Vectius Marcellus, a Roman knight, 

 the steward of Nero, changed places with each other, although the public 

 highway was interposed. 



" Chap. 86 (84) — Wonderful Circumstances Attending Earthquakes. 

 " Inundations of the sea take place at the same time with earthquakes ; 

 the water being impregnated with the same spirit, and received into the bosom 

 of the earth which subsides. The greatest earthquake which has occurred 

 in our memory was in the reign of Tiberius, by which twelve cities of 

 Asia were laid prostrate in one night. They occurred the most frequently 

 during the Punic war, when we had accounts brought to Rome of fifty-seven 

 earthquakes in the space of a single year. It was during this year that the 

 Carthagenians and the Romans, who were fighting at the lake Thrasimenus, 

 were neither of them sensible of a very great shock during the battle. Nor 

 is it an evil merely consisting in the danger which is produced by the motion; 

 it is an equal or a greater evil when it is considered as a prodigy. The city 

 of Rome never experienced a shock, which was not the forerunner of some 

 great calamity. 



" Chap. 87 (85) — In what Place the Sea has Receded. 

 " The same cause produces an increase of the land ; the vapour, when 

 it cannot burst out forcibly lifting up the surface. For the land is not merely 

 produced by what is brought down the rivers, as the islands called Echinades 

 are formed by the river Achelous, and the greater part of Egypt by the 

 Nile, where, according to Homer, it was a day and a night's journey from 



