Also: samowar

A term used in modern literature to describe a heating device found in calidae piscinae. It consisted of a cylindrical metal container placed into the centre of the floor and ensured, just as testudines in normal alvei, that the water of the pool could be kept warm. To heat this device directly, a service corridor ran underneath the pool to a furnace underneath the samovar. Only a few examples of this device are known, mainly in Italy.

The samovar in the piscina calida of the Suburban Baths of Pompeii (photos: Konogan Beaufay).