KOMAN EXI'LOUATION FL^ND. 7 Of the tiiuc of the KopiihUo we h;ive few Imihiiu;^.-, reiiKiiiiiii;;, and these are of no great importance ; the best is the Kniporium, of which tlic construction is very riule. In the time of the Emperors the appli- cation of the iisual tests of archaeological evidence has been found equally useful. Knowing that the " construction of the same period is always the same," wc had only to choose some one good, well-ascertained historical type of each jjcriod^ and then compare the construction of other buildings not dated w ith them. By means of these historical tv-pes we ascertained that, as a general rule, the brickwork of each century is tiic easiest guide to the date of a building. In the first century, nine or ten to the foot. In the second, only eight. In the third century, six. In tl»c fourtli century, four. This is a general guide, and a remarkably useful and safe one. When the wall is intended to be cased with mtu-ble or plaster for painting this rule does not always api)ly ; but in general the bricklayer did not know or care whether his brick wall was to be cased or not ; he laid his bricks according to the manner in which he had been taught to lay them as a good workman, and would not lay theux in any other manner : it was the same then as now, and the quality of the bricks themselves iti always a safe guide. These rules for brickwork, therefore, can ginerally be depended on ; and so can the thickness of the mortar 'ind the size of the small diamond-shaped wedges of tufa in the Opus retlculaium. Applying these archfcological tests on the Palatine to the Palaces of the Cicsars, we see how little reliance can be placed in what are called the Roman traditions, which were only the conjectures of learned men living in the last three centuries, who had often much less o[)pnrtuuity than we have of forming an opinion. Their traditions j)lace the House of Augustus on the site of the Villa Mills, on the southern side of the gi-cat fosse of Komulus. There is no authority whatever for this conjecture; the construction is entirely of the time of Domitian ; it is ]>art of the great palace of his time, built partly' over the great fosse of Komulus, in which was the State Palace — "the St. James's Palace of the time of the Empire." The real palace or House of Augustus, we are distinctly told by Suetonius, was that of an ordinary citizen, named Hortensius, which he cliose because it was in the Arx of Komulus, and near the place where the House of Komulus then stood. " This house had no ornament, and the Senate were not satisfied with it; but Augustus refused to give it uj), and lived in the same rooms for forty yeai-s." The Senate, therefore, a few years afterwards added state apartments to it. We have exactly such a house excavated in 1870-71, miscalled the House of the Father of Tiberius, because there is an under- ground passage from it to what is called the Palace of Tiberius, on the top of the north-cast corner of the Palatine. But the construction of that house is of the time of Trajan and Hadrian. The real House of Tiberius is on the western clift', near the Velabrun), the construction of it is the same as that of the northern wall of the Pnetorian Camj), which is an historical type of his time. The Palace of Caligula is down below, "near the Forum Komanum," as we are UAiX by Suetonius, that he used the tonq)le of Castor and Pollux a.s a vestibule to it, and we find there the brick walls of the first century, but not in the palace above,
