proportionable decrease of the Sound, according to its distance.
- As a Convex Speculum reflects the Object less, but somewhat brighter or clearer: So a Convex Corpus Obstans repels the Sound (insensibly) smaller; but somewhat quicker (though weaker) than otherwise it would be.
As a Concave Speculum reflects the Object bigger , more obscure and Inverted : So a Concave Corpus Obstans ecchoes back the Sound (insensibly) bigger , slower (though stronger ) and also inverted ; but never according to the order of Words. Nor do I think it possible for the Art of Man to contrive a Single Eccho , that shall invert the Sound, and repeat backwards; because then the Words last spoken, that is, which do last occur to the Corpus Obstans , must first be repell'd; which cannot be: For where, in the mean time, should the first Words hang, and be conceal'd, or lie dormant? Or how, after such a pause, be reviv'd and animated again into Motion? Yet in complicated or