All these mighty ruins of Agrigentum, and the whole mountain on which it stands, says Mr. Brydone, is composed of an immense concretion of seashells, run together, and cemented by a kind of sand, or gravel, and now become as hard, and perhaps more durable, than even marble itself. This stone is white before it has been exposed to the air; but in the temples and other ruins it is become "set," of a very dark brown. These shells are found on the very summit of the mountain, which is at least fourteen or fifteen hundred feet above the level of the sea. The celebrated Empedocles was a native of this city; one of the finest spirits that ever adorned the earth. His saying, in regard to his fellow-citizens, is well known;--viz., that they squandered their money so excessively every day, that they seemed to expect it could never be exhausted; and that they built with such solidity and magnificence, as if they thought they should live for ever[8]. NO. VI.--ALBA LONGA. It has been stated, or rather speculated upon, that the entire history of this place is no other than a romance. By Dionysius of Halicarnassus, however, it is said to have existed four hundred and eighty-seven years; when, after having been the founder of thirty other Latin cities, it was destroyed by the Roman power. That it existed, is also attested by the ruins that now remain. Its ancient characteristics are thus described by Dionysius:--it was so built, with regard to its mountain and lake, that it occupied a space between them, each serving like a wall of defence to the city. It was long supposed to have been situated where Palazzuolo now is. Sir W. Gell says, "On passing up the new road, running from the dry bed of the river Albanus, where it crosses the Appian Way, near Bolerillæ, and leading to the Villa Torlonia, or Castel Gandolfo, a few ancient tombs were observed about half way up the ascent; and further examination showed, that these tombs had once bordered an ancient road, now almost obliterated. It was obvious, that such a road must have led from some place on the plain, to another on the mountain. Toward the sea, the high tower of Pratica (Lavinium) lay in the direct line of the road; and it seemed certain that the city on the mountain, to which it led, could have been no other than Alba Longa. Climbing upward among the bushes, ponderous blocks of stone were discovered, evidently the remains of the walls of this city. By a farther search, more were found. At a distance a small cavern was discovered; and not only the remains of a well, but part of a column of stone, two feet four inches in diameter. At a higher point the shore was covered with ruins, consisting of large blocks of rectangular stones, nearly buried in the soil, and scarcely discernible among the bushes."