... the still glassy lake that sleeps
Beneath Aricia's trees.
Aricia has changed its site; the small modern town has flown up to the level of the arx, to be approached by Albano by almost the only work on which we do not grudge to see the name of Pius IX. The viaduct of that "Pontifex Optimus Maximus"—his votaries seem never quite to distinguish between him and Jupiter—is really a work worthy of Cæsars or consuls. Below it new Aricia has left the elder city, its fragments of walls and of the Appian Way, to be sought for in the valley below, the crater, so wise men tell us, of an extinct volcano, the biggest surely even in this region where craters meet us at every step. Scraps of primæval wall, hardly to be distinguished from the rocks, prepare us for what we are to see at places further out of the ordinary track; walls of the days of Sulla join on alike to what we have seen at Rome, and to what we are to see at Cori. But, after all, the "still glassy lake" to which the grove of the "rex nemorensis" has given the name of Nemi, is the true glory of Aricia. How well we remember being puzzled years and years ago with the thrilling run of the lines—
Those trees in whose dim shadow
The ghastly priest doth reign,
The priest who slew the slayer,
And shall himself be slain.
In these days the fault would be held to lie with the poet for venturing on an allusion which it might need a little research to take in. In those days we thought in such cases that the fault lay with ourselves; we admired without understanding till we lighted on the explanation which enabled us to understand as well. As such a process is a wholesome one, we will leave the lines without comment; not to speak of books of reference, the story will be found, in a somewhat grotesque form, in Dr. Merivale's chapter on the reign of Caius, better known as Caligula.
The ghastly priest has gone from Nemi; but the lake is there still, and the successors of the trees. Access is courteously granted by the present owner, who, we may believe, has never slain anybody, and who, we hope, may not be slain himself. But though we may admire Nemi from close by, we do not fully understand Nemi and its place among things, till we can look upon it in company with its greater fellow of Alba. That is, we must climb the Alban mount, or a good part of its height. But we go first to the Alban lake itself; and to do so we go along its rim and slide down the side of its crater. There we find the emissarius, so deftly cut in the rock, and which has done its work so well for so many ages. Who made it? Camillus, or some one long before Camillus? The men who built the great cloaca of Rome were quite capable of cutting the hole through the rock of Alba, without any message from Delphi or any design against the walls of Veii. Whoever the borer was, he did his work far more thoroughly than Claudius ages afterwards did his for the Fucine lake, which work it has been left for the Torlonia of our own day to finish. But no one, we may suppose, wished at any time to drain the Alban lake, but only to keep it in order. How needful such a work is we do not fully grasp till we can look down from above. Then we take in the strict accuracy of the name crater. We see the two lakes, greater and smaller, side by side, like two basins in the strictest sense, in which, at some time which geologists may fix, but which it is enough for history to say that it was long before the oldest primæval wall, the powers of water supplanted those of fire. We take in how the larger lake, with its narrow rim, in some parts of its circuit with its low rim, liable to be swollen, but with no natural outlet for its waters, might easily come to overflow, if artificial means had not been, in some early time, taken to check it.