=311. The Great Swimming Pool and the _Tepidarium_.=--All this is usually preliminary to a splashing plunge into the clear cool _natatio_, the great swimming pool of unheated water, which is nearly 200 feet long by 100 broad, and in which scores of Rome’s noblest dignitaries now are to be seen splashing, swimming, and cavorting, with perfect self-respect beside a much greater number of the plebeians. For the many who do not prefer a warm bath, this is sufficient refreshment on a summer day, and presently they will call their attendants to bring towels, strigils, and ointments and hasten home. But your true _habitué_ makes almost as much of his baths as of his dinners. He delights in hot baths and all the refreshments that go with them. “People want to be parboiled,” once declared Seneca disgustedly. A hot bath involves an elaborate process. Often one will omit the frigidarium with its cold shock, or take it later. In any case one goes on to a second enormous chamber, perhaps the finest in the whole building. A majestic dome soars over broad pavement. The pillars and the fretwork on the ceiling and vaulting groan with heavy gilding. The groups of statues flanking each of the huge marble-incrusted piers are themselves of heroic size. The light streams down over the polished marbles of the walls and pendentives, upon hundreds of persons lolling about on stone benches, conversing, or lazily meditating. A warm mist is rising; one feels as if in a plant house of tropical exotics, while the elaborate mosaic designs are pleasantly warm under one’s bare feet. Such luxury of course is enjoyed in the _tepidarium_ where the bathers are gently warmed before the actual hot bath. It is an oblong hall, nearly as large as the great cold swimming tank,[200] and, as stated, the decorations are almost overpowering in their richness. Anybody will explain that the floors are composed largely of hollow tiles through which warm air of just the right temperature is being continually forced from the great system of charcoal furnaces (“hypocausts”) located in the substructures of the thermæ. =312. The Hot Baths (_Caldaria_): Their Sensuous Luxury.=--At intervals some person rises from the couches and hastens away to one of the smaller chambers located at the four corners of the tepidarium. These are the actual _caldaria_ (hot baths), wherein a perpetual fine steam is rising. The water here is so hot that only experienced bathers can find a plunge in the large porphyry tanks enjoyable. If one can endure the heat, however, soon it becomes a kind of stupid bliss to lie back motionless in the heated water, gazing upward to the vaulted ceiling which is skilfully painted in a deep blue interspersed with trees, foliage, birds, and gilt stars, as if one were dropping off to slumber in the forest some summer evening! If the acme of life is merely sensuous enjoyment, what can existence offer greatly surpassing this!