In theca eius tympani, sive loculamentum est, unum foramen excavetur habens canaliculum, qua calculus liberatus ab obstantia cum ceciderit in vas aereum, sonitum significet.
One of these openings is to have a small channel adjoining it. Here when a stone can move without hindrance, it falls into the bronze vessel and announces this by a sound.
final_alignments\Vitruvius_Architecture_Book_10.json