tazza—­eighteen feet in circumference—­the finest specimen of Egyptian breccia to be seen in Rome, both in the Villa Albani, and the vase of the same material in the chamber of Candelabra in the Vatican, in which the prevailing green colour is crossed by several stripes of pure white quartz, may thus have been sculptured out of a portion of littoral deposit formed from the ruins of the crystalline rocks of the mountain group of Sinai.  There is something extremely interesting and suggestive to the imagination in the twofold origin of these conglomerate ornaments of the palaces of Rome.  Around them gather the wonderful associations of ancient human history, and the still more awe-inspiring associations of geological history.  They speak to us of the conquests of Rome in the desolate tracts of Nubia and Arabia, from which the spoils that enriched its palaces and temples were derived; and of the existence of coast-lines, when Egypt was a gulf stretching from the Mediterranean to the Mountains of the Moon, which became silted up by slow accumulations.  Their language, in both relations, is that of ruin.  They are survivors both of the ruins of Nature and of Man, and are made up of the wrecks of both.  Older far than the marbles which keep them company in the sculptor’s halls and churches of Rome, and whose human history is equally eventful, their materials were deposited along the shore of a vanished sea, when the mountains that yielded these marbles lay as calcareous mud in its depths.

Alabasters, of which there are numerous varieties, from pure diaphanous white to the deepest black, were favourite decorative materials with the ancient Romans.  The different kinds were used for the walls of baths, vases, busts, pillars, and sepulchral lamps, in which the light shining through the transparent sides had an agreeable softness.  Cornelius Nepos, as quoted by Pliny, speaks of having seen columns of alabaster thirty-two feet in length; and Pliny says that he himself had seen thirty huge pillars in the dining-hall of Callistus, the freedman of Claudius.  One such column still exists in the Villa Albani, which is twenty-two and a half feet in height.  The ancients obtained large blocks of alabaster from quarries in Thebes in Egypt, in the neighbourhood of Damascus, and on Mount Taurus.  They imported some kinds also from Cyprus, Spain, and Northern Africa.  They obtained varieties nearer home, in different parts of Italy, such as the beautiful Alabastro di Tivoli, employed by Hadrian in his villa, and which appears to have been brought from Terni, where it still exists in abundance.  From the quarry near Volterra the Etruscans obtained the alabaster for their cinerary urns.  The European alabasters are accumulated masses of stalactite and stalagmite, formed by the slow dropping of water charged with sulphate of lime, to which circumstance they owe the parallel stripes or concentric circles with which they are marked, while the rich and delicate varieties of colouring