a kind of famous phials or glases, chiefly made in Germany, which have the property of being flexible, and emitting a vehement noise by the human breath.—They are also called vexing glasses by the Germans (vexier glaser), on account of the fright and disturbance they occasion by their reflection. The anaclastic glasses are a low kind of phials with flat bellies, resembling inverted funnels, whose bottoms are very thin, scarce surpassing the thickness of an onion peel: this bottom is not quite flat, but a little convex. But upon applying the mouth to the orifice, and gently inhaling, or as it were sucking out the air, the bottom gives way with a prodigious crack, and of convex becomes concave. On the contrary, upon expiring or breathing gently into the orifice of the same glass, the bottom with no less noise bounds back to its former place, and becomes gibbous as before.—The anaclastic glasses first taken notice of were in the castle of Goldbach; where one of the academists Nature Curiosorum, having seen and made experiments on them, published a piece extemp on their history and phenomena. They are all made of a fine white glass. It is to be observed, 1. That if anaclastics the bottom be concave at the time of inspiration, it will burst; and the like will happen if it be convex at the time of expiration. 2. A strong breath will have the same effect even under the contrary circumstances.