Note 185 — Chapter IV · BASILICAS, THEATRES, AND BATHS.

According to Prof. Middleton this magnificent hall appears to have been what Spartianus calls the cella soliaris, the ceiling of which he says was formed of interlaced bars of gilt bronze. When the excavations in this hall were being made, many tons of fragments of iron girders were found. These were (according to Prof. Aitchison) compound girders, formed of two T bars riveted together, and then cased in bronze. A sort of lattice-work ceiling had been formed with these bronze-cased girders, the panels being probably filled in with concrete made of light pumice-stone, worked with fine stucco reliefs, painted and gilt. Prof. Middleton is of opinion that the central part over the swimming-bath was left open for the admission of light. In the upper part of the walls deep sinkings to receive the ends of the great girders which supported the ceiling are clearly visible.