Vitruvius mentions nothing of amphitheatres; therefore he probably published his book before that of Taurus was built: as for Cæsar’s, it belonged not to masonry, being carpenter’s work; in which he was a very great master, as in every thing else: so that we must form our notions of these things from the works themselves, and the ruins that time has spared. The parts of an amphitheatre are these: the _arena_ or space within, the scene of action; the _euripus_, or river that generally encompassed the verge of it; the _podium_, or parapet at bottom; the _itinera_, or _viæ_, which were the walks between certain series of seats; the _ascensus_, steps or stairs; the _pulpita_ or _tribunalia_, a sort of covered chair of state, where the emperor, his legate, the prætor or chief magistrate of a city, sat; the _cathedræ_, where the senators, foreign ambassadors, and great personages, sat; the _gradus_, or common seats; the _præcinctiones_, which I suppose balustrades; the _aditus_ or _vomitoria_, being the passages from the stairs withinside to the seats, a metaphorical name, from the people pouring themselves through them with violence; the _cunei_, which were the space of seats comprehended between two of those passages, so called from their wedge-like shape; the _porticus_, or galleries within, partly for magnificence, and partly for convenience: all these particulars are easily apprehended from inspection of schemes and sections of these works in many authors. Some of them could not, others need not to be in our work; therefore I shall occasionally enlarge upon those pertinent to this subject, as they fall in our way in the description. [Illustration: 50 _The Geometrical Groundplot of the Roman Amphitheatre at Dorchester_ _Aug. 22. 1723._ _Stukeley designʳ._] [Sidenote: TAB. LXXVII.] [Sidenote: TAB. LXXVIII.] [Sidenote: TAB. L.] [Sidenote: TAB. LIII.]