the air is penned in the hollow of the mouth or throat. In the percussion of a hard body against air is required hardness of the body and quick motion, and sometimes communication with a concave, as in the cittern, lute, beating of the air, &c.; but in the percussion of a hard body against a hard body, the hollow, or the quick motion, is less required.

There is a talk of a white gunpowder, which should give percussion without noise. It is sure that nitre, which is white, is of great force for expulsion, yet in such wise as the speedy kindling doth much enhance both the percussion and the noise; but the quick kindling is caused specially by the coal of willows, which is black. Therefore, if a composition were made of sulphur and nitre, and a modicum of camphor, it is like that the kindling would be slower, and the percussion not so jarring and sharp; whence much might be diminished of the sound, but with loss too in the strength of the percussion. To be further inquired.

It can be taken for an argument, that sound is manifestly some kind of local motion in the air, that it so suddenly fails; because, in all cutting or impulsion of the air, the air quite recovers and restores itself, which also water doth through many circles, albeit not so speedily as the air.

Of the Confusion and Perturbation of Sounds. In the act of sight, visibles from one part impede not visibles from other parts; but all the visibles which offer themselves from every part, lands, waters, woods, the sun, buildings, men, are at once represented to the eyes. But, if so many voices or sounds did at once issue from several parts, the hearing should be plainly confounded, nor might distinctly perceive them.

The greater sound confoundeth the less, that it should not be heard; but spiritual species, as they speak of a diverse kind from sound, confuse not sound, but altogether and at once hang in the air, the one little or nothing troubling the other; as light, or colour, heat and cold, smells, magnetic

Extinction.

The lasting of the sound of a bell that is struck, or of a string, which seems to be prolonged, and gradually to fade, comes not rightly of the first percussion, but the trembling of the body percussed generates in the air continually new sound. For, if that trembling be checked, and the bell or string stayed, the sound quickly dies; as in virginals, where, if the quill be dropped so that it touch the string, the sound ceases.

A bell hanging in the air gives a far louder and more enduring sound if it be chimed upon with a hammer on the outside, than if it stood fixed, and were in like manner chimed upon with a hammer. And of the more enduring sound the reason is rendered already, because it trembleth longer. But that even the first sound in the hanging bell is more resounding, in the standing less, would be further inquired.

Likewise a drinking cup of silver or of glass that is fillipped, if it be left alone, gives a sound louder and more lasting; but if the foot of the cup be steadied with the other hand, a far duller, and of shorter stay.

The sound which is yielded in the viol or cittern is plainly not made by the percussion between the finger, or the quill, and the string, or between the finger, or the quill, and the air, but by the finger impelling, and thereafter the string flying back, and in that recoil percussing the air. Therefore, when the string is moved with a bow, not by the finger, or a quill, the sound can be continued at pleasure, through the roughness of the string of the bow, which is a little smeared with rosin; whence it slides not on the string, nor once strikes it, but holds and continually tortureth it, out of which motion the sound is maintained. VOL. III.-68

yet do greatly hinder or disturb sounds.

The cause wherefore many visibles are at once represented unto the eyes, the one not confounding the other, would seem to be none other but this: that visibles are not seen except in a right line, but sounds are heard even in a line oblique, or arcuate. Therefore, as many objects in the area of the sphere of sight, as are conveyed, there be so many cones of beams, nor ever one cone doth coincide with another; neither do the vertices of the cones meet in the same point, because they are carried by right lines. But sounds, which are carried by lines, both right and arcuate, can meet easily in one point, and so are confused. The same seemeth to be the cause wherefore a more bright colour drowns not a more dim colour; nevertheless, a greater light obscures and hides a weaker light, because light is perceived in an arched line, like as sound. For, although the very flame of a candle be not seen except in a right line, yet does the light that is everywhere spread round attain to the sight in lines, arched in respect of the body of the candle: the like is the case of the sun, or flame. Now, if it be objected that neither is light itself seen except in a right line from air illuminated, it is true; but I think that this as well happens to sound: for neither is sound heard unless in right lines from some part of the sphere of sound, whither the first pulsation arrives. But colour, which is nothing other than the image unequally reflected of the light, spreadeth around so weak species, that it little or nothing tinges the air adjacent, unless where the colours are conveyed in right lines be. tween the object and the eye.

Let there be a trial made with a double recorder in which let there be two fipples, at each end one, so as they may be played in unison: the hollow

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.

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

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

seen.

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 made at a distance in the air at large, or conversely, the sound be produced at the hollow trunk, the ear being placed at a distance in the air at large, favour more the perception of the

sense.

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.