this Instrument, he shall, at the Sound of a single Viol, seem to hear a whole Consort and all true Harmony. By which means this Instrument has much the advantage of the Polyscope.
And thus much may suffice for comparing the Improvements made upon Refracted Seeing and Hearing; I call it Refracted Hearing, because made through a Medium, viz. thick Air, or an Instrument, through which the Sound passing is broken or refracted.
III. Reflected Vision has been improv'd by the Invention of Looking-glasses and Polished Metals, whether Plane, Concave, or Convex; and these two last, either Spherical, Oval, Cylindrical, Conical, Hyperbolical, or of several other shapes; all which cause a different Reflection, and vary the Phænomena.
Thus also Reflext Audition, made by Ecchoes, may be improv'd, by contriving several sorts of Artificial Ecchoes; as 'tis no hard matter to do in almost any place.
For (speaking in the general) *Any Sound, falling