Inundations of the sea take place at the same time with earthquakes[556]; the water being impregnated with the same spirit[557], 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[558], 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[559] that the Carthaginians and the Romans, who were fighting at the lake Thrasimenus, were neither of them sensible of a very great shock during the battle[560]. 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[561]. The city of Rome never experienced a shock, which was not the forerunner of some great calamity. CHAP. 87. (85.)—IN WHAT PLACES 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[562]. 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 the main land to the island of Pharos[563]; but, in some cases, by the receding of the sea, as, according to the same author, was the case with the Circæan isles[564]. The same thing also happened in the harbour of Ambracia, for a space of 10,000 paces, and was also said to have taken place for 5000 at the Piræus of Athens[565], and likewise at Ephesus, where formerly the sea washed the walls of the temple of Diana. Indeed, if we may believe Herodotus[566], the sea came beyond Memphis, as far as the mountains of Æthiopia, and also from the plains of Arabia. The sea also surrounded Ilium and the whole of Teuthrania, and covered the plain through which the Mæander flows[567]. CHAP. 88. (86.)—THE MODE IN WHICH ISLANDS RISE UP. Land is sometimes formed in a different manner, rising suddenly out of the sea, as if nature was compensating the earth for its losses[568], restoring in one place what she had swallowed up in another. CHAP. 89. (87.)—WHAT ISLANDS HAVE BEEN FORMED, AND AT WHAT PERIODS.