142 COMPARATIVE ARCHITECTURE. underneath which were the furnaces and other rooms for the service of the baths. The Thermae of Caracalla, Rome (a.d. 212-235) (Nos. 46 f, G, H, K and 59 a), accommodating 1,600 bathers, are the most important of all the remains, and give a splendid idea of their size and magnificence. The entire site including gardens was raised on an artificial platform 20 feet high, measuring 1,150 feet (over one-fifth of a mile) each way, not including the segmental projection on three of the sides. Under this platform were communicating corridors leading to various parts of the establishment, vaulted chambers used as stores, the hypocaust, and furnaces for heating the water and hot air ducts. Along the road front was a colonnade having behind it a row of small chambers in two stories, the lower at the street level, probably used as shops, and the upper on the platform level, for private "slipper" baths. The entrance to the establishment was in the centre of the north-eastern fagade, and led to the large open enclosure laid out for wrestling and other games, around which, in the segmental projections and elsewhere, were grouped in the various halls for dramatic representations and lectures. The central building, used entirely for bathing, measured 750 feet by 380 feet, and therefore covered an area of 285,000 square feet, i.e., about equal to West- minster Palace (including Westminster Hall), but greater than either the British Museum or the London Law Courts, Only four doorways were formed on the north-east side, which was exposed to cold winds, but large columned openings, giing access to the gardens, were a feature of the south-western front. Although now in ruins, restorations have been made which show the relative positions of the Tepidarium, Calidarium (with sudatio), Frigidarium (with piscina), Sphaeristeria (for gymnastics), Apodyteria (dressing rooms), and other apartments. The planning of this and similar buildings is very instructive to architectural students and worthy of careful study, being laid out on axial lines, which, while providing for the practical requirements of the bathers, produced vistas through the various halls and saloons. Moreover, by the system of exedrae and screens of columns, loss of scale was prevented, and the vastness of the building was emphasized. Internally the Tepidarium, forming the principal hall, around which the subsidiary apartments were grouped, constituted the controlling feature of the plan to which the other apartments were subordinated. It was 170 feet by 82 feet, roofed with an immense semicircular intersecting concrete vault, 108 feet above the floor, formed in three compartments, and supported on eight portions of entablature resting on granite columns, 38 feet high and 5 feet 4 inches in diameter, placed in front of the massive piers. This
