National Geographic : 1946 Nov
Furnaces Beneath the Baths THE GLORY that was Rome showed at times a battered and tarnished reverse to its medallion. Upon the ground level of the resplendent baths all was magnificence and ease for unhurried patrons; but in brick and rubble-walled caverns under the mosaic floors public slaves sweated to keep the furnaces alight. They stoked the fires, carried in the fagots, supervised the flow of water, patrolled the intricately twisted passageways, and led a mole's life in stifling, overheated quarters. Modern Trier on the Moselle River occupies, with its 88,000 inhabitants, only a portion of the ancient city which once stood there and which a late Latin poet called "Rome beyond the Alps," the second city of the Empire. In Trier, which was the favorite residence of the first Christian em peror, Constantine, may be seen the most extensive Roman remains in Europe north of the Alps. Time-battered remnants of the vast public baths built in Trier in Constantine's reign have supplied extremely de tailed information on the underground arrangement and workings of a great Roman thermal establishment. From this source is drawn most of the pictorial detail of Mr. Herget's illustration. The squat, square shafts of brick and stone in the middle background support a solid concrete slab which serves as the underpinning of a warm pool in a large rectangular room similar to that illustrated in the preceding painting. Since the hot air from the open hearths of the furnaces, sucked through the labyrinth of underground passages, circulates under the floors and through the hollow tile inside the walls, not only the room containing the pool but adjoining apart ments are kept warm. Itisquestionable whether abetter way has ever been devised toheat alarge building ina reasonably mild climate. An aqueduct supplied the establishment with asteady flow of cold, clear water, which minor conduits of stuccoed masonry, terra-cotta pipes,and lead tubes and fittings dis tributed to the elaborateseries ofpools and basins. Hot water was conveyed through pliable lead pipes directly from the boilers to spigots of bronze inthesweating room and the tepid pool. Since the soft lead couldbeeasily cut, joined, and melted together, check and control valves were setinthe pipes without any attempt to thread the metal. For the same reason there were no Tjoints or right-angled arms and bends. The pipes couldbehung like modern telephone cables on hooks as theywere carried under and through the floors and inside the walls. Boilers of bronze or brass operated on the principle of huge kettles. Under the boilers wood (probably very seldom lignite or soft coal) was burned inopen hearths, rather like domestic fireplaces of today. Long brick flues assured a steady draft and carried the soot and smoke well above the building. Although much of the octopuslike plumbing looks crude to the modern eye, it mustbejudged by what itaccomplished. The colossal scale of some ofthe thermal establishments proves that the heating system must have been little short of extraordinary. There was never any lack ofhot water.