'Sudatorium', the term in
architecture for the vaulted sweating-room (''sudor'', sweat) of the Roman
thermae, referred to in
Vitruvius (v. 2), and there called the ''concamerata sudatio''.
In order to obtain the great heat required, the whole wall was lined with vertical
terra-cotta flue pipes of rectangular section, placed side by side, through which the hot air and the smoke from the
suspensura passed to an exit in the roof.
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