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pipe being of a double length, and continued in one; let two together play the same tune at either end, and let it be noted whether the sound be confused, or amplified, or dulled.
Let there be two hollow trunks taken, and joined together crosswise, so as they shall open the one into the other, in the place where they are joined; and let two speak into the direct and transverse trunk, and let the ears of two be in like manner applied to the opposite ends, and observe whether the voices confuse one another.
To inquire, which bodies, and of what solidity and thickness, altogether debar and shut out sound; as, also, which more or less dull, although they intercept it not wholly. For as yet is it not known which mediums interposed be more propitious, which more adverse. Therefore, let there be trial made in gold, stone, glass, cloth, water, oil, and of the thickness of each. Hereof is all need to inquire further.
Air is the aptest, and, as it were, the sole medium of sound. Again, the moister air (I judge) better conveyeth sound than the drier; but in a fog what happeneth I remember not. Also, the night air better than by day; but this can be
ascribed to the silence.
Inquire touching the medium of flame, what its operation shall be in respect of sound; whether, to wit, a flame of some thickness altogether stop and intercept sound, or at least deaden it more than the air. This can be seen in bonfires.
Also, to inquire concerning the medium of air vehemently agitated. For, although wind carry sound, yet I deem that any vehement wind doth somewhat trouble sound, so as it shall be heard less far, even with the wind, than in still weather, of which let there be more inquiry made.
To see what sound brass or iron, red-hot, yields, struck with a hammer, compared to that which it gives cold.
Of the Penetration of Sounds.
The aëtites, or eagle stone, hath like a kernel or yolk of the stone, which being shaken makes a flat sound; so a hawk's bell, [stopped,] but a much clearer if there be a chink.
Let inquiry be made of divers, if they hear at all under water, especially that is of any deep
ness; and let this be distinctly inquired, not only whether they hear any sound at all from above. which is made in the air, but also, whether they hear the percussion of the body of the water within the water, where no air is. I have made this trial in a bath; a pail of a good size with the mouth turned over was, in such wise, pressed evenly down, as it carried the air fairly down with it, in its hollow, below the water, to the depth of a hand-breath; and in this manner the pail was held down with the hands, that it should not overturn nor rise: then a diver put his head within the pail, and did speak: his voice was heard, speaking; and even his speech was articulately distinguished, but wonderfully shrill, and almost like a whistling, as the voice useth to be heard in a play of puppets.
Let it be exactly inquired, so as it be clearly rendered positive whether sound can be generated, except there be air betwixt the percussing and the percussed body. As, if two pebbles hanging by a string be let down into a basin of water, or a river, and shaken, so as they shall strike together in the midst of the water; or let an open pair of tongs be thrust down into the water, and there knapped; and let it be noted whether they give a sound, and what. I do suppose that divers, in swimming, make no noise under the water; unless there may perchance be some, by the succession of motion under the surface of the water, and the water thence striking the air.
There is no doubt but in bladders tied, and not quite full, and shaken, there is a sound given, namely, of the liquor contained in them, and no less a sound is given on letting down a stone into water, when it strikes the bottom of the vessel. But in the former trial air is intermingled; in the second, the percussion of the bottom of the vessel by the stone communicates with the air without the vessel. But, after the first percussion, it needeth not that there be air intermediate through the whole area of the sphere deferent; for that is shown by the trial of one speaking in a pail under the water, where part of the deferent from the water is not air, but the wood of
the pail, and the water; whence the sound is sharpened, and minished, and lost.
But, because it is manifest that sound passes through and penetrates hard bodies, (as potters' earth and glass;) and it is also most certain (although hitherto concealed from men's observation) that there is, in every tangible body, some pneumatical part, besides the gross parts intermixed, it is to be considered whether penetration of sound of this kind come not thence, for that the pneumatical or aerial parts of the tangible body communicate with the outer air.
Take a vessel of silver, and another of wood, full of water; take a pair of iron tongs, and knap them in the water in the vessels, at the distance of a thumb's breadth, perhaps, or more. from the
air, unless where the opening or passage is ex ceedingly strait. For if one stand in any place utterly closed, so as the sound may not penetrate at all, and that in any part soever of a sphere of sound, and there be a small opening made, the articulate voice shall enter through that opening, and in fine through as many openings as you shall choose to make through the whole round of the sphere of sound : so as it is manifest that that whole articulation of sound is conveyed entire in these minutest parts of the air, not less than if the air were at large on every side.
bottom: you shall hear the sound of the tongs | every part of the air, not the whole in the whole knapped in the vessel of silver much more resounding than in the wooden one. Whereas, if the two vessels were empty, and you knapped the tongs at the same distance, there should be little difference, or none. Whence it appears, first, that where is no air that can be elided, but only water, sound is given; next, that the sound given by the percussion communicates better with the vessel through water than through air. The mouth being close shut, there is made a murmur (such as dumb persons use to make) by the throat; if the nostrils likewise be fast closed, no murmur can be made. Whence it appears, that that sound by the throat is not effected unless through the opening which lies between the throat and the nostrils.
Of the Carriage of Sounds, and their Direction or Spreading; and of the Area which Sound fills, together and severally.
All sound is diffused in a sphere from the place of the percussion, and fills the whole area of this sphere to a certain limit, upwards, downwards, sideways, and every way.
Throughout this orb the sound is loudest close to the stroke; thence, in the proportion of the distance, it grows more faint, until it vanishes. The limits of this sphere are extended some little by reason of the quickness of hearing; yet is there something uttermost, whither, to the most delicate sense, sound reaches not.
There is something, I think, in the direction of the first impulsion; for, if a man should stand in an open pulpit in the fields, and shout, the voice, I judge, should be further heard forwards from the speaker than behind. So, if ordnance, or a harquebuss be discharged, I judge that the sound shall be further heard before the ordnance or harquebuss than behind it.
Whether there be any thing in the ascension of sound upwards, or in the descension of sound downwards, which may further sound, or make it cease nearer, doth not appear. The sound is indeed well heard, if one speak from a high window or turret, by those who stand upon the ground; and, contrariwise, being uttered by those that stand upon the ground from the window or turret, but by whether more easily, or further off, let better inquiry be made.
Pulpits are used for speaking in assemblies, and generals did usually speak standing upon mounds of sods; yet is it is no wise hence confirmed that sound easilier descends than it rises, since the cause hereof may be the liberty of the air in the higher place, not thronged or hindered, as below amongst the crowd, but not the readier motion downwards. Therefore, let not the contemplation stay in this instance, but let a trial be made where other things are equal.
The power of the sound is received whole in
It is, however, to be observed whether sounds proceeding from the greater pulsations of the air (such as are made by the discharge of ordnance) become not more exile when they enter by those small apertures; for it may be that the subtilties of sound shall enter unconfused, but the whole crash, or roar, not so well.
The rays of visible bodies do not strike the sense, unless they be conveyed through the medium in straight lines, and the interposition of any opaque, in a right line, intercepts the sight, although every thing else be on all sides wholly open. But sound, if there be a dilatation or passage, whether by arching over, or by inverted arching downwards, or laterally, or even by winding, perishes not, but arrives. Nevertheless, I judge that sound is more strongly carried in straight lines, betwixt the pulsations and the ear, and that by its archings and windings it is somewhat broken; as, if there be a wall betwixt the speaker and the hearer, I think that the voice shall not be so well heard as if the wall were away. I judge, too, that if the speaker or the hearer be placed at a little distance from the wall, the voice shall be better heard than nigh unto the wall, because the arching so much the less departs from a right line. But this also would be further inquired.
If the ear be laid to the one end of any tube or long hollow trunk, and a voice speak softly at the other opening of the tube, such a voice shall be heard, which, being as softly spoken in the air at large, should not arrive, nor be heard. Whence it is clear, that that confining of the air helps to the conveying of the voice, without confusion.
It is also a common opinion, that, other things being equal, the voice is better heard within doors than abroad; but whether the voice be better heard when the ear is out of doors, and the voice within the house; or contrariwise, when the voice is out of doors, and the ear within the house, may be further inquired; albeit herein also the opinion is received, that what is abroad is better heard within doors, than what is within, abroad.
It is common to hearing and sight, and, indeed, in a certain measure, to the other senses, that the attention of the perceiving mind, and express direction to perceiving, help somewhat to perceiv
ing, as when one looks steadfastly, or (as they say) pricks his ears.
Sounds are not carried so far, articulate and distinct, as their species, and a confused coil of them; for the hum of voices can be heard where the articulate words themselves are not heard; and a confused tinkling of music, when the harmony itself or tune is not heard.
Sound is preserved, at the best, in a hollow trunk. Therefore let there be taken a hollow trunk of a good length, and let it be put out from the window of a lower chamber; let one speak by thrusting of his head out of the window, at one end of the trunk, as softly as ever he may : let another lay his ear to the other end of the trunk, standing below upon the ground: let this be done in like wise reversely, by speaking from below, and laying to of the ear above, and from this trial let a judgment be made, whether the voice ascend or descend more easily, or even alike. They deliver for certain, that there be some places and buildings so vaulted, that if one stand in a certain part of the chamber, and speak, he can be better heard at some distance than near. All harmony appeareth to sound somewhat fuller and deeper at a little remoteness from the place of the sound than near; so as something should seem to happen to hearing about sound, like as happeneth to sight about visible species, that some removal from the organ of the sense furthereth the perception of the sense. But in that opinion may be twofold error. First, because in the act of sight there be, perhaps, beams required from the object to the pupil, which there cannot be where the object toucheth the pupil, which between the hearing and the sound is not required. But much rather, because to seeing is light needed. But an object touching the pupil intercepts the light; whereas nothing of this kind befalls to hearing. And, in the second place, because to sight there needeth not always a medium; forasmuch as, in the removing of cataracts of the eyes, the little silver needle wherewith the cataracts are removed, even when it moveth upon the pupil within the coat of the eye, is excellently
In objects of sight, if the eye be placed in the dark, and the object in the light, it shall do well; but if the object be placed in the dark, and the eye in the light, you shall not see. So, if a thin veil or net-work be cast over the eyes, the object is well seen; if upon the object, it confounds sight. And albeit, that perhaps neither of these agreeth to sound and hearing, yet may they advertise us that trials be made, whether the ear set against the hollow trunk, if the sound be inade at a distance in the air at large, or conversely, the sound be produced at the hollow trank, the ear being placed at a distance in the air at large, favour more the perception of the
of the Variety of the Bodies which yield Sound; and the Instruments; and of the Species of Sounds which occur.
The kinds of sounds appear to receive such a division: loud, soft, sharp or treble, base; musical, unmusical; interior or whispering, exterior or sounding; simple, compounded, original, reflected; so as they are divisions six.
The stronger the first pulsation shall be, and the dilatation the more free, and without let, the greater is the sound given the weaker the percussion, and more disturbed the dilatation, the less. Treble sounds are carried as far, and perchance farther than base. Let this be better inquired. Accordingly as the concave of a bell shall be greater, it giveth a baser sound; the less, the more treble.
The bigger a string, the baser sound it shall yield; the less, the more treble.
A string, the more tightly strained, the more treble sound shall it yield; the looser, the baser: so as a little bigger string more tightly strained, and a less more slackly, shall give the same note. In trumpets, in like wise, in flutes, horns, and recorders, pipes, also in the mouth of a man whistling, the more narrow and straight they are, they give the more treble sound; the wider, or more open, the baser.
In flutes, the air, issuing by a hole nearer the breath, yields a more treble sound; by one more distant, a baser: so a little bigger flute by the nearer hole, and a smaller by the more removed, may give the same note.
In some stringed instruments (as in the viol, citterns, and the like) men have found a skill for the straining of the strings, beyond the first straining, so as compressing them with the fingers lower down or higher up, they strain them to the alteration of the note.
If a drinking-cup of glass or silver be taken and fillipped, if the water stand higher in the cup, and the cup be fuller, it will give a more treble sound; if lower, and the cup be more empty, a baser.
In a hollow pipe, such as they use for shooting of birds, if one whistle with the mouth, setting the mouth to one end of the tube, the sound is dulled, truly, to the bystander; but if the ear be laid to the other end, it gives a most sharp sound, so as it shall hardly be borne.
Let there be a trial made with a trunk, in the part where the ear is laid, narrow, in the part where the mouth is set, wider, and conversely; whether the sound be rendered more treble or baser, after the manner of mirrors, which contract or enlarge the objects of sight.
Of the Multiplication, Majoration, Diminution, and Fraction of Sound.
It would be seen in what, how, way, manner, sound can be artificially magnified and multiplied.
Mirrors do effect both in sight. Now, the sudden reflection of sound seems to turn to augmentation; for if the voice and echo be yielded together, need is that the sound be not distinguished, but magnified. Therefore, sounds rivers are greater, the water resounding and blending itself with the original sound.
I have also noted that when a round-house is made in water-conduits, then a long vault, and then a greater chamber, (such as is to be seen in the fields by Charing Cross near London,) if you cry at the window or slit of the round-house, and one stand by the window of the greater chamber, a far more fearful roaring is heard than by one standing where the cry is made.
I bethink me that in the play of puppets, the speaking is such as it is heard distinctly, but far sharper and more exile than in the air at large; as happens in mirrors that render letters far smaller than they are in the ordinary medium: so as sound appears plainly possible by art to be both amplified and rendered more exile.
Children hold the horn of a bent bow betwixt their teeth, and with an arrow strike the string, whence is produced a more resounding sound, and a far greater boom, than if the bow were not held in the teeth; which they ascribe to the consent which the bones of the teeth have with the bone of hearing; since, conversely also, by a certain harsh sound in the hearing, the teeth too be set on edge.
In like manner, let a lance touch the wood of the belly of an harp, especially of the hole in it at the hollow end, and be held with the teeth at the other end, and the harp struck; the sound is made greater by taking hold with the teeth, that is to say, to him that so taketh hold.
It is most assured (however unnoted) that the force, which after the first percussion carries on balls, or arrows, or darts, and the like, is situated in the minute parts of the body discharged, and not in the air continually carrying it, like a boat in the water. This being premised, it may be considered whether sound might not be lessened in ordnance or a harquebuss, without much weakening of the percussion, in this manner. Let there be a harquebuss made with a barrel of a pretty strength, so as it break not easily; in the barrel let there be four or five holes made, not like chinks, but round, about the middle of the barrel. The percussion hath already gotten its force, excepting so far as by reason of the length of the barrel it may be increased; but the percussion of the air at the mouth of the harquebuss, which generates the sound, will be much attenuated by the emission of sound through those holes in the middle of the barrel, before that the air enclosed arrive at the mouth of the harquebuss. Therefore it is probable that the sound and boom shall by many parts be diminished.
Of the Repercussion of Sounds and Echo. The repercussion of sounds (which we call echo) can be taken for an argument that sound is not a local motion of the air; for if it were, the repercussion should be made in manner conformable to the original, as happens in all corporeal repercussions. But in sound, wherein such an exact generation is required, as in the voice, which hath so many organs, and in musical inwhich yield the repercussed sound have nothing struments, which be curiously framed, the things such, but are merely rude, having almost nothing save this, that sound passes not through them.
Of the Consents and Dissents of Audibles and Visibles, and of other so called Spiritual Species.
They agree in these:
Both are diffused in a spherical compass or orb, and fill the whole area of that sphere, and are carried to very distant spaces, and wax faint by degrees, according to the distance of the object, then vanish. Both carry their figurations and differences into minute portions of their orb, entire and unconfused, so as they are perceived through small crannies no otherwise than in an open place.
Both are of exceedingly sudden and swift generation and dilatation, and conversely they are extinguished, and perish suddenly and quickly.
Both take and convey minute and exquisite differences, as of colours, figures, motions, distances, in visibles; of articulate voices, of musical tones, and of their swift changes and trepidation, in audibles.
Both, in their virtue and force, appear neither to emit any corporeal substance into their mediums or their orb, nor even to give forth or provoke a local perceptible motion in their mediums, but to convey certain spiritual species, of which the nature and manner is unknown.
Both appear to be not generative of any other virtue or quality besides their proper virtue, and so far to work, being else barren.
Both in their proper action appear, as if corporeally, to work three things. The first, that the stronger object drowns and confounds the weaker; as the light of the sun, the light of a candle, the report of ordnance, the voice. The second, that the more excellent object destroys the weaker sense; as the light of the sun, the eye, a violent sound close at the ear, the hearing. The third, that both are repercussed, as in mirrors and the echo.
Neither doth the object of the one confound or hinder the object of the other; as light or colour, sound, or contrariwise.
Both affect the sense in animals, and that by objects in greater or less degrees grateful odious but they affect also after their own man
ner inanimates proportionate, and having (as | cured of cataracts of the eyes, when the little silseemeth) a conformity with the organs of the ver needle moved over the very pupil of his eye, senses; as colours, a mirror, that is crystalline like the eye; sounds, the places of reverberation, which seem, likewise, to resemble the bone and cavern of the ear.
and did touch it, he, without any medium, (that silver needle being far narrower than the pupil itself of the eye,) saw perfectly the needle. The second, that the cave of the ear is distinctly inter
Both work diversely, accordingly as they have posed before the organ of hearing, so as, being their mediums well or ill disposed.
To both the medium the most conducible and propitious is the air. In both the stretching of the sense, and, as it were, its erection to perceiving, availeth somewhat in more nice objects.
They differ in these:
The species of visibles appear to be as if emissions of beams from the visible body, almost like odours. But the species of audibles appear more to partake of a local motion, like the percussions which are made in the air: that whereas bodies for the most part work in two manners, by communication of their nature, or by an impression or signature of their motion, that diffusion in visibles appeareth more to partake of the former manner; in audibles, of the latter.
The dilatation of sounds appears to be more evidently carried by the air than of visibles. For I judge that a vehement wind shall not so much hinder any visible afar off, as a sound; I understand the wind blowing contrary.
It is a notable difference, whence also many less differences flow, that visibles (original light excepted) are not carried but by right lines, whilst sounds are carried by arcuate lines.
Hence it happens, that visibles confound not one another, that are represented together: sounds contrarily. Hence it happens, that the solidity of the substance seems not greatly to hinder sight, provided only the positions of the parts of the body be after a simple order and with straight passages, as in glass, water, crystal, diamond; but a little silk or linen cloth breaks the sight, though they be bodies very thin and porous; but cloths of this kind little or nothing hinder hearing, which those solids do exceedingly. Hence it happens, that unto the reverberation of visibles a small mirror suffices, or like transpicuous body, let it be only placed in a right line, where the visibles pass; but unto making of the reverberation of echo, it needeth also to confine the sound from the side, because it is carried to all sides. The visible object is further carried, in proportion, than sound.
Visibles, too nearly approached to the eye, are not so well seen as at some little distance, so as the beams may meet in a more acute angle; but in hearing, the nearer the better. But herein there may be twofold error. The first, because to seeing there is required light; but if the object be brought very near to the eye, this is shut out. For I have heard of one trustworthy, which was
without, the sound is altogether unable to touch the bone and membrane of hearing.
The species of sight are more swiftly conveyed than sounds, as appeareth in the flash and report of guns; also in lightning and thunder, where the thunder is heard after a while.
I conceive also that the species of sound do hang longer in the air than visibles. For, although neither do these perish on the instant, as we see in a ring spinning, and lute-strings fillipped, and in twilight and the like; yet I deem that sounds, for that they are carried by the wind, stay longer.
The beams of light being gathered, induce heat also, which is an action diverse from the visible quality. In like manner, if it be true that shouts have cast down birds flying over, that is also an action exceedingly diverse from the audible quality.
There seemeth not in visibles to be found an object as odious, and noisome to the sense, as in audibles; but they affect it more evenly; for things foul to sight rather offend by moving of the fancy concerning foul things than of themselves; but in audibles the grating of a saw that is sharpened, and other like sounds, cause a horror; and a discordant note in music is straightways refused and loathed,
It is not assured, that there is refraction in sounds, as in beams. But, doubtless, sounds do rebound: but that is to be ascribed to reflection. For, I do not think, if sounds pass through diverse mediums, as air, cloth, wood, that there be one place of the sound, where it is carried, another where it is heard, which is the property of refraction; but refraction seems to depend upon action, in right lines, which pertains not to sound.
But contraction of sound, and its dilatation, according to the disposition of the medium, happens, undoubtedly, as in the speaking of puppets, and under water: the sound is contracted within that cell, which abroad is dispersed; as by mirrors visibles are dilated and contracted.
A tremulous medium (as smoke in visibles) makes the visible objects also to tremble; but in sounds nothing such is yet found, unless, perchance, the rise and fall by winds. For the trembling in the nightingale-pipe is trembling of the percussion, not of the medium.
Going from great light into the dark, or out of the dark into the light, the sight is some little confused; but whether the like be after very loud noises, or a great silence, would be inquired.