Laconicum

This room was much like a present-day sauna, filled with hot, dry air. It was heated by hot air circulating from the furnace in vaulted channels under the floor and then evacuated through channels within the walls. The bathers sat on small, stool-like brick benches in a room covered with a brick barrel vault and lit by a small round window in the external wall. To conserve heat, the window was certainly glazed (remnants of such glazing were found in other baths of the period in Egypt.)