At one end of the caldarium we find the bath basin, alveus; at the other is the support of the labrum, which has disappeared. In the niche above the latter are two vents for the draft, and above the niche was a round window. This room, as most of the others, was dimly lighted. The little round window of the anteroom is shown in our plate. There were two similar windows in the lunette of the apodyterium, above the roof of the anteroom; they are not seen in our plate, having at one time been entirely covered up by the construction of a wall to support the roof. A similar window was very likely placed at the end of the tepidarium, over the roof of the frigidarium; and perhaps these were supplemented by holes in the crown of the arched ceilings, as in the women's apodyterium.

The women's baths are entered from the court through a long anteroom (6); the dressing room is connected also with the two side streets by means of corridors (1, 5). Originally there was no communication between the women's baths and the palaestra.

The apodyterium (2) is the best preserved room of the entire building, and also the most ancient. It shows almost no traces of the catastrophe. The vaulted ceiling is intact. The smooth, white stucco on the walls and the simple cornice at the base of the lunettes date from the time of the first builders. Now, as then, light is admitted only through two small openings in the crown of the vault and a window in the west lunette. To a modern visitor the interior seems gloomy. The pavement, of lozenge-shaped, reddish glazed tiles, belongs to the same early period. There is a strip of basaltic flags connecting the door of one of the corridors (1) with that of the tepidarium. This much travelled path seems to indicate that many ladies—particularly, we may assume, in the winter—went at once into the more comfortable tepidarium without stopping in the dressing room. Along the walls were benches, and above them niches, as in the men's apodyterium. In the time of the Empire the fronts of the niches, finely carved in tufa, were overlaid with a thick coating of stucco, the upper part being ornamented with designs in relief.

The women had no frigidarium. A large basin for cold baths was built at the west end of the dressing room, but this also is a later addition; before it was made, those who wished for cold baths must have contented themselves with portable bath tubs.

The tepidarium (3) and caldarium (4) are in a better state of preservation than those of the men's baths, which they so closely resemble in all their arrangements that a detailed description is unnecessary. In their present form they are not so ancient as the apodyterium, and the decoration is less elaborate than that of the corresponding rooms on the other side.

The labrum is intact, a round, shallow basin of white marble resting on a support of masonry; it has here no separate niche. The bath basin in the caldarium also retains its veneering of white marble, with an overflow pipe of bronze at the upper edge; it is about two feet deep. In such basins the bathers leaned against the sloping back, which for this reason was called a cushion (pulvinus) by Vitruvius. This alveus would accommodate eight bathers, that in the men's caldarium perhaps ten. Places were probably assigned in numerical order, each bather awaiting his turn. Those who did not wish to wait, or preferred to bathe by themselves, might use individual bath tubs of bronze. Remains of such a tub, as well as of bronze benches, were found in this room. Near the bottom of the alveus in front is an opening, through which the water could be let out; when it was emptied, the water ran over the white mosaic floor, which was thus cleaned.

In the time of the Early Empire it became the fashion to bathe with very warm water. 'People want to be parboiled,' Seneca exclaims. The construction of the alveus, however, was not well adapted to conserve the heat, and an ingenious contrivance was devised to remedy the difficulty, which may best be explained with the help of our illustration, showing the arrangement of the bath basin in room 4 ([Fig. 88]). A large hot air flue, D, led directly from the furnace to the hollow space, C, under the alveus, A. Above this flue was a long bronze heater, B, in the form of a half cylinder, with one end opening into the end of the alveus. As the bottom of the heater was six inches lower than that of the alveus, the cooler water from the basin would flow down into it and be heated again, a circulation being thus maintained.

Fig. 88.—The bath basin in the women's caldarium—longitudinal and transverse sections, showing the arrangement for heating the water.
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