Full text: Bacon, Francis: Sylva sylvarum

Natural Hiſtory; more than Beaſts; becauſe naturally they are more delighted with them,
and practiſe them more, as appeareth in their Singing. We ſee alſo, that
thoſe that teach Birds to ſing, do keep them waking, to increaſe their
attention. We ſee alſo, that Cock-Birds, amongſt Singing-Birds, are ever
the better ſingers, which may be, becauſe they are more lively, and liſten



Labor and Intention to imitate Voices, doth conduce muchto Imitation: And therefore we ſee, that there be certain Pantomimi, that will repreſent
the Voices of Players of Interludes, ſo to life, as if you ſee them not, you
would think they were thoſe Players themſelves, and ſo the Voices of other
men that they hear.



There have been ſome that could counterfeit the diſtance of Voices,
(which is a ſecondary object of Hearing) in ſuch ſort; as when they ſtand
faſt by you, you would think the Speech came from afar off, in a fearful
manner. How this is done, may be further enquired; but I ſee no greatuſe
of it, but for Impoſture, in counterfeiting ghoſts or ſpirits.



THere be three kindes of Reflexions of Sounds; a Reflexion Concurrent, a Re-
flexion Iterant, which we call Eccho, and a Super-reflexion, or an Eccho of an
Eccho, whereof the firſt hath been handled in the Title of Magnitude of
Sounds. The latter two we will now ſpeak of.


in Conſort,
touching the
Reflexion of

The Reflexion of Species Viſible by Mirrors, you may command, becauſe
paſſing it Right Lines, they may be guided to any point: But the Reflexion
of Sounds, is hard to maſter; becauſe the ſound filling great ſpaces in arched
Lines, cannot be ſo guided. And therefore, we ſee there hath not been
practiſed any means to make Artificial Eccho’s. And no Eccho already
known, returneth in a very narrow room.



The Natural Eccho’s are made upon Walls, Woods, Rocks, Hills, and
Banks: As for Waters being near, they make a Concurrent Eccho; but
being further off, (as upon a large River) they make an Interant Eccho: Forthere is no difference between the Concurrent Eccho, and the Iterant,
but the quickneſs or ſlowneſs of the return. But there is no doubt, but Wa-
ter doth help the Delation of Eccho, as well as it helpeth the Delation of
Original Sounds.



It is certain (as hath been formerly touched,) that if you ſpeak thorow
a Trunck, ſtopped at the further end, you ſhall finde a blaſt return upon your
mouth, but no ſound at all. The cauſeis, for that the cloſeneſs, which pre-
ſerveth the original, is not able to preſerve the reflected ſound; beſides that,
Eccho’s are ſeldom created, but by loud Sounds. And therefore there is
leſs hope of Artificial Eccho’s in Air, pentin a narrow concave. Neverthe-
leſs it hath been tryed, that one leaning over a Well of Twenty five fathom
deep, and ſpeaking, though but ſoftly, (yet not ſo ſoft as a whiſper) the
Water returned a good audible Eccho. It would be tryed, whether ſpeaking
in Caves, where there is no iſſue, ſave where you ſpeak, will not yield Eccho’s
as Wells do.



The Eccho cometh as the Original Sound doth in a round orb of Air: It were good to try the creating of the Eccho, where the Body repercuſſing
maketh an Angle: As againſt the Return of a Wall, & c. Alſo we ſee that
in Mirrors, there is the like Angle of Incidence, from the Object to the
Glaſs, and from the Glaſs to the Eye. And if you ſtrike a Ball ſide-long, not
full upon the Surface, the rebound will be as much the contrary way; whe-


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