A drive of a few miles to the South of Aci Reale brings us to Trezza, a small village built of lava. A short distance from the shore are the celebrated _Scogli di Ciclopi_, or rocks of the Cyclops, said to be those which Polyphemus hurled at Ulysses after his escape from the cave. The rocks, seven in number, form small islets, the largest of which, the Isola d'Aci, is about 3000 feet in circumference, and 150 feet high. It consists of crudely columnar basalt capped by a kind of marl. Near the top of the island there is a cave called the "Grotto of Polyphemus," also a cistern of water. To the south of this island a very picturesque rock rises from the sea. It is 2000 feet in circumference and about 200 feet in height, and consists of columnar basalt in four and eight-sided prisms, but not very regular; a hard calcareous substance is found in their interstices. Fine crystals of analcime are sometimes met with in the basalts of the Cyclops Islands. Lyell considers these basalts "the most ancient monuments of volcanic action within the region of Etna." A few miles south of the Isole di Ciclopi are the bay and city of Catania. We started from the latter when we commenced our ascent of Etna, and now on returning to it, we completed the circuit of the mountain by its base-road of 87 miles. Katana (~Katanê~) is believed to have been founded about 730 B.C. by a Greek colony of Naxos, which had originally come from Chalcis. The city maintained its independence till the time of Hieron, who expelled the original inhabitants in 476 B.C., and peopled the city with Syracusans and inhabitants of the Peloponnesus to the number of 10,000. At the same time the name of the city was changed to Aetna ([Greek: Aitnê]). In 461 B.C., however, the old inhabitants retook their city, and drove out the newly-settled strangers, who betook themselves to Inessa, occupied it, and changed its name to _Aetna_. At a later period the Katanians sided with the Athenians against the Syracusans. But in 403 B.C. Dionysius of Syracuse took and plundered the city, sold the inhabitants as slaves, and established in it a body of Campanian mercenaries. The latter quitted it and retired to Aetna in 396 B.C., when the city was taken by the Carthaginians after a battle off the rocks of the Cyclops. Katana submitted to the Romans in 263 B.C., during the first Punic War, and it soon became a very populous city. Cicero mentions it as a wealthy city and important seaport. During the Middle Ages it underwent many changes both at the hands of nature and of man; it belonged in succession to the Goths, Saracens, and Normans; and in 1169 was destroyed by an earthquake, during which 15,000 of its inhabitants perished. Again in 1669, and 1693, it was almost destroyed by earthquakes. The present town is comparatively new, many of its more ancient remains are covered with lava, among them the remains of a fine Greco-Roman theatre, in which it is probable that Alcibiades addressed