[Illustration: Scale 50 ft. to 1 in. Scale 100 ft. to 1 in. 176. Tomb of Aruns, Albano.] There are not in Etruria any features sufficiently marked to characterise a style of architecture, nor any pillars with their accessories which can be considered to constitute an order. It is true that in some of the rock-cut tombs square piers support the roof; and in one or two instances rounded pillars are found, but these are either without mouldings or ornamented only with Roman details, betraying the lateness of their execution. The absence of built examples of the class of tombs found in the rock prevents us from recognising any of those peculiarities of construction which sometimes are as characteristic of the style and as worthy of attention as the more purely ornamental parts. From their city gates, their aqueducts and bridges, we know that the Etruscans used the radiating arch at an early age, with deep voussoirs and elegant mouldings, giving it that character of strength which the Romans afterwards imparted to their works of the same class. The Cloaca Maxima of Rome (Woodcut No. 104) must be considered as a work executed under Etruscan superintendence, and a very perfect specimen of the class. At the same time the Etruscans used the pointed arch, constructed horizontally, and seem to have had the same predilection for it which characterised the cognate Pelasgian race in Greece. A gateway at Arpino (Woodcut No. 177) is almost identical with that at Thoricus (Woodcut No. 126), but larger and more elegant; and there are many specimens of the same class found in Italy. The portion of an aqueduct at Tusculum, shown in Woodcut No. 178, is a curious transition specimen, where the two stones meeting at the apex (usually called the Egyptian form, being the first step towards the true arch) are combined with a substructure of horizontal converging masonry. In either of these instances the horizontal arch is a legitimate mode of construction, and may have been used long after the principle of the radiating arch was known. The great convenience of the latter, as enabling large spaces to be spanned even with brick or the smallest stones, and thus dispensing with the necessity for stones of very large dimensions, led ultimately to its universal adoption. Subsequently, when the pointed form of the radiating arch was introduced, no motive remained for the retention of the horizontal method, and it was entirely abandoned. [Illustration: 177. Gateway at Arpino.] [Illustration: 178. Aqueduct at Tusculum.] CHAPTER II. ROME. INTRODUCTION.