Public amenities included a theater, baths, and a fire department. The theater, built in Augustus’ reign (about 12 B.C.), and often restored and enlarged, seats 2700, and is used nowadays for outdoor performances of Greek and Roman plays. Behind it is a portico where theater patrons might saunter, with a temple in its midst built by Domitian. In a combination of business with pleasure typical of Ostia, seventy offices face the four sides of the portico. These offices, to be discussed in more detail below, were maintained by local branches of firms from all over the Empire. Ostia was well equipped with public baths. The three most interesting belong to the middle years of the second century A.D. The Baths of Neptune, near the theater (_Regio_ II, _Insula_ iv), have a large entrance hall paved with a spirited mosaic showing Neptune driving four sea-horses, surrounded by Tritons, Nereids, dolphins ridden by Cupids, fabulous sea monsters of every kind, and two young men swimming. The Baths of the Seven Sages (_Reg._ III,x) are named from a painting in their dressing room which depicts the seven wise men of Greece, each labelled with an off-color couplet describing in some detail the intimate connection between constipation and the intellectual life. The most interesting of all are the Forum Baths (_Reg._ I,xii). A recent study by an American heating engineer, E. D. Thatcher, underlines how well the Romans understood the principles of radiant heating (of floors, walls, bathing pools, and even vaults), and orientation of bathing rooms to catch the maximum amount of sunlight, and to provide a windbreak, so that, although the large windows were not glazed, the rooms were usable on most days of the year, even in winter, with additional provision, proved by put-holes, of a rigging of canvas for the coldest days. If the windows had been glazed, bathers could not have acquired a tan, whose therapeutic and fashionable implications were the same for an Ostian as for us. Thatcher calculates that an unglazed room in the Forum Baths was usable ninety-eight per cent of the time: hence glazing was not worth while. The Romans knew, as the Forum Baths show, that the flow of heat is always from a hotter body to a colder one, and that air temperature alone is no criterion of comfort. In fact one may be comfortable in a much lower air temperature than that found in most American houses and public buildings, provided one does not lose more heat than one is generating at the time. The floor and wall surfaces of the Forum Baths radiated enough warmth to keep bathers comfortable in relatively cool air with unglazed windows. The courtyard of the baths was paved with white mosaic to reflect light and heat. A room which commanded a maximum of sunlight has radiant heat in the floor only, not in the walls. The various rooms of the baths were heated to different temperatures; Romans achieved with differently heated areas what we achieve with thermostats.