A kind of sonorous glasses, chiefly made in Germany. They have the property of being flexible, and emitting a vehement noise by the human breath. The anaclastic glasses are a low kind of phials, with flat bellies, resembling inverted funnels, whose bottoms are very thin, scarcely surpassing the thickness of an onion-peel; this bottom is not quite flat, but a little convex. On applying the mouth to the orifice, and gently inspiring, or, as it were, sucking out the air, the bottom gives way with a tremendous crash, and the convex becomes concave. On the contrary, upon expiring or breathing gently into the orifice of the same glass, the bottom, with no less noise, bends back to its former place, and becomes gibbous as before.