Downdraught kiln

A downdraught kiln is a:
 * 1) a kiln in which heat enters the kiln chamber from the top and passes down through the ware (Ries 1912)
 * 2) a type of single kiln of circular or rectangular shape, with holes in the floor communicating with a flue and chimney (Stratton 1993)
 * 3) a kiln in which the hot gases from the fireboxes first rise to the roof, then descend through the setting, and are finally withdrawn through flues in the kiln-floor (Dodd & Murfin 1994)