! 5' 



^aturall Hiflory ; 



251 



252 



253 



254 



[Experiments 

 in Confort 

 ! touching r the 

 \cenfent and 

 \Dijjent be- 

 tween Vifibles 

 and Audible s. 



255 



256 



257 



Hill. For the Houfe will give zBack Eccho One taking it from the others 

 and the latter the weaker. 



There are certain Letters, that an Eccho will hardly cxprefs As 5, 

 for one, Efpecially being Principall in a Word. I remember well, that 

 when I went to the Eccho at ?mt- Charenton, there was an Old Parifian, that 

 took it to be the Work of Spirits, and of good Spirits. For, ((aid he) call 

 Satan, and the Eccho will not deliver back the Devils name 3 But will fay, 

 Vafen Which is as much in French, as Apage, or Avoid. And thereby I 

 did hap to find, that an Eccho would not return S, being but a HifTingand 

 an Interiour Sound. 



Eccho s are fome more fudden, and chop again, as foone as the Voice is 

 delivered 5 As hath been partly faid: Others are more deliberate, that is 

 give more Space between the Voice, and the Eccho which is caufed by the 

 locall Nearnefs, or Diftance : Some will report a longer Train of Words 

 And fome a fhorter : Some more loud (full as loud as the Originally and 

 fometimes more loud-,) And fome weaker and fainter. 



Where Eccho s come from feverall Parts, at the fame diftance, they muft 

 needs make (as it were) a Quire of Eccho 's, and fo make the Report greater, 

 and even a Continued Eccho $ which you (hall find in fome Hills, thatftand 

 encompafled. Theatre-like. 



It doth not yet appear, that there is Reft 'action in Sounds, as well as in 

 Species Vifible. For I do not think, that if a Sound mould pafs through 

 divers Mediums, (as Air, Cloth, Wood) it would deliver the Sound, in a dif- 

 fering Pface, from that unto which it is deferred 7 which is the Proper Effect 

 of Refraction. But Ma] oration which is alfo the Work of Rt fr - action } ,appea- 

 reth plafnly in Sounds, (as hath been handled at full-,) But it is notbyDi* 

 verfityof Mediums. 



We have biter, for Demonftrations fake, ufed in divers 

 Inflames) the Examples of the Sight, and Things Vifible, to il- 

 luftratcthe Nature of Sounds* But we think good now to pro- 

 fec ute that Comparifon more fully. 



CONSENT OF VISIBLES 

 and Audibles. 



Both of them fpread themselves in Round, and fill a whole Floare or Orbe, 

 unto certain Limits : And are carried a great way. And dolanguifh 

 and lellen by degrees, according to the Diftance of the objects from the 

 Senfories. 



Both of them have the whole Species in every (mall portion of the Air 

 or Medium, So as the Species do pafs through fmall Cranies, without 

 Confufion : As we fee ordinarily in Levels > as to the Eie y And in Cranies | 

 or Chinks, as to the Sound. 



Both of them are of a fudden and eafie Generation and Delation ; And like- 

 wife perifh fwiftly,md fuddenly ; As if you remove the Light Or touch the 

 Bodies that give the Sound. 



Both 



