The roof-tiles were of the usual kinds, flat oblong tegulae with flanges, measuring 24 by 19 by 20 inches,[[2461]] with semi-cylindrical imbrices. They were laid in lines parallel to the long ridges of the roofs, so that the water converged into the gutter-tiles at the angles, whence it fell into the impluvium. These gutters, however, were not confined to the angles of the openings, but were sometimes ranged along the whole length of the sides, as we have seen; those at the angles only seem to be earlier in date. They are not found on the exteriors of buildings. The front of the gutter was usually in the form of a vertical kymation moulding, but was sometimes simply chamfered. Antefixal ornaments terminating the covering or ridge-tiles are not invariable, but are found at different periods. The earliest examples are in the form of palmettes, but the later exhibit a great variety[[2462]]: comic masks, a head in low relief on a palmette, or a head surmounted by a palmette. Of the latter class thirty-eight were found in 1861. In the Augustan period ideal heads of gods and demi-gods are sometimes found.[[2463]]
Von Rohden, in summing up (p. 14), is of the opinion that terracotta roof-decoration at Pompeii was comparatively rare. In the whole record of excavations only twenty-three water-spouts are mentioned, though it is probable that many were never registered. In scarcely more than twelve private houses have as many pieces been found as would suffice for the whole of the atrium and peristyle roofs, and nearly all of these are of late date. The discovery of isolated pieces in a house seems to show that they were used up again in the restorations after the earthquake of A.D. 63.
There are also some good examples of roof-tiles among those which have been found at Ostia, both in baths and private houses; some of the latter came from a house of which the brickwork bore inscriptions with the names of consuls of Hadrian’s reign. The arrangement of the roof-tiles is that described on p. [341]; the antefixal ornaments are usually in the form of palmettes or acanthus leaves, with maeander below; but heads of deities, such as Venus and Neptune,[[2464]] or of Medusa, and tragic masks were also found. Two exceptional examples had groups in relief of Neptune drawn over the sea by hippocamps, and of the statue of Cybele in the ship drawn by the Vestal Virgin Claudia.[[2465]]
Tiles of the size known as bipedales are also used for lining the walls of rooms. They are found in Roman villas in Britain, and are ornamented on one side with various incised patterns, made with a tool in the wet clay. On some found at Ridgewell in Essex the decoration consists of lozenges, rosettes, and other ornaments,[[2466]] like those on the Pile Cinq-Mars already described; they are often found covered with the stucco with which the walls were plastered. At Pompeii, Orvieto, and elsewhere the stucco-painted walls were constructed with tegulae mammatae placed edgewise, and connected with the main walls by leaden cramps, the brick lining being thus detached from the walls by a narrow interval which served as an air-cavity.[[2467]] This was a frequent proceeding, and was also contrived with flanged tiles; it corresponds with the system prescribed by Vitruvius for keeping damp from the painted walls of rooms.[[2468]] It was also largely employed in baths and bathrooms, the object being both to keep the walls dry and to allow hot air to circulate from the hypocausts and warm the rooms. In the cold climate of Britain the Romans found this a universal necessity, and instances may be observed in many of their villas; but, as far as can be observed, the general method of warming was by an extensive system of pipes under the floors rather than up the walls.[[2469]] These tiles are pierced with holes, by means of which they were attached to the walls by plugs or nails of lead. In the castrum at Jublains a chamber is yet partly standing with one of its sides coated with tiles of this kind.[[2470]]
From Middleton.
FIG. 192. METHOD OF HEATING THE BATHS IN THE THERMAE OF CARACALLA.
| A A | Concrete wall, faced with brick, shown in vertical and horizontal sections. |
| B | Lower part of wall, with no brick facing. |
| C C | Suspensura, or upper floor of Hypocaust, supported by pillars. |
| D D | Another floor, with support only at edges. |
| E E | Marble flooring. |
| F F | Marble plinth and wall lining. |
| G G | Under floor of Hypocaust, paved with large tiles. |
| H H | Horizontal and vertical sections of flue-tiles lining wall of Calidarium. |
| a a | Iron hold-fasts. |
| J J | Socket-jointed flue-pipe of Tepidarium. |
| K | Rain-water pipe (in horizontal section). |
| L L | Vaults of crypt, made of pumice-stone concrete. |
More commonly, however, a peculiar kind of tile was used for warming the hot rooms (sudationes) of baths, and in villas when required. They were hollow parallelopipeds, known as tubi, with a hole in the side for the escape of the air which traversed them, the usual dimensions being about 16 by 6 by 5 inches.[[2471]] Seneca speaks of pipes inserted in walls, which allowed the warmth to circulate and warm both the upper and lower stories equally[[2472]]; and the younger Pliny mentions the air-holes (fenestrae) in the pipes which warmed his bedroom, by means of which the temperature could be regulated at pleasure.[[2473]] Sometimes, as in the baths of Caracalla and the house of the Vestals, the whole side of a wall was composed of flue-tiles covered with cement,[[2474]] which was made to adhere by scoring the sides with wavy or diagonal lines, as in the flat tiles described above, and as is often done in modern building. The whole system of heating, which may be seen in the baths of Caracalla, is very instructive (Fig. [192]): the walls were of concrete with brick facing, through which a system of flues of socket-jointed tiles passes upwards from the hypocaust below, effectually warming every part.[[2475]]
