136 Mtfcellanea Curtofa. 



he ftands in a wrong place, to receive the refle- 

 cted Sound, which pafles over his head, under 

 his Feet, or to one fide of him ; which therefore 

 may be heard by a Man (landing in that place, 

 where the reflected Sound will come, provided no 

 interpos'd Body does intercept it ; but not by him, 

 that firft made it. 



I fhall further make out the comparifon 'twixt 

 Reflex' d Vifion and Audition, by thefe following 

 JPropoJitions. 



I. As a Plain Speculum reflects the ObjeH in 

 its due Dimenfions and Colours allowing for 

 their difference of appearance, according to their 

 diftance : So a Plane Corpus Obftans reflects the 

 Sound back in its due Tone and Loudnefs ; if al- 

 lowance be likewife made for the proportiona- 

 ble decreafe of the Sound, according to its di- 

 ftance. 



z. As a Convex Speculum reflects the ObjeB 

 left, but (bmewhat brighter or clearer: So a 

 Convex Corpus Obftans repels the Sound (infenfi- 

 bly ) /mailer , but Tome what quicker (though ma- 

 ker) than otherwife it would be. 



3. As a Concave Speculum reflects .the Object 

 bigger, more obfcure and Inverted : So a Concave 

 Corpus Obpans ecchoes back the Sound (inlenfi- 

 b\y) bigger, flower (though ftronger) and alio 

 inverted j but never according to the order of 

 "JYords. Nor do I think it poflible for the Art 

 of Man to contrive a Single Eccho, that fhall 

 invert the Sound, and repeat backwards ; be- 

 caufe then the Words laft fpoken, that is, which 

 do laft occur to the Corpus Obftans, muft firft 

 be repell'd ; which cannot be : For where, in 

 the mean time, fliould the firft Words hang, and 

 be conceal'd, or lie dormant ? Or how, after 

 fuch a paufe, be reviv'd and animated again 



intq 



