152 COMPARATIVE ARCHITECTURE, The external fa9ade is divided into four stories. The three lower ones have their walls pierced with arches, and are orna- mented with half columns of the Tuscan, Ionic, and Corinthian orders, the two latter being on pedestals. The upper story has Corinthian pilasters, and the height to the top of this order is 157 feet. Between the pilasters are the corbels used to support the masts of the velarium. In criticizing the general architectural character of this wonderful building (No 63), points worthy of notice are : — i. The multiplicity of its parts, viz., three tiers of apparently countless arcades encircling the exterior, divided and united by three tiers of orders. ii. The grand sweeping lines of the unbroken entablatures which entirely surround the building, iii. The purely decorative use of the Classic orders of archi- tecture which being superimposed are in strong contrast to the Grecian method of single orders, iv. The thick piers behind the orders, connected by eighty arches and supporting the weight of the structure. The proportions of the attached columns on the facade, which all have the same lower diameter are unusual : — The Tuscan column is about 9 J diameters high and the Ionic and Corinthian about 8f diameters. The Colosseum was used as a stone quarry by the builders of later times, materials being taken from it for the construction of many Renaissance buildings (page 456). The Amphitheatre, Verona (No. 64), is in splendid pre- servation, all the stone seats being intact, although only four bays of the external wall are still standing. Other well-known examples are the Amphitheatres at Pompeii, Capua, Pola in Istria, Nimes, Aries, El Djem near Carthage, and remains of a roughly made example at Dorchester, in Dorset. CIRCI. The plan of a Roman Circus was an adaptation of a Greek stadium, but, however, was used for chariot or horse races, while the Greek stadium was principally used for foot races and athletic sports. At Rome there were several important examples, among which were the Circus Maximus and those of Maxentius, Domitian, Hadrian, Nero, Flaminius, and Sallust. The Circus Maxentius (No. 60 c) near Rome, also known as the Circus of Romulus, was built by Maxentius in a.d. 311. Although only part of it now remains, it is the most perfect example of a Roman Circus existing. It consisted of a long open circular-ended arena with a "spina' along its axis. Surrounding this were rows of marble seats supported by raking vaults and an
