An entire body of philosophy according to the principles of the famous Renate Des Cartes in three books, (I) the institution ... (II) the history of nature ... (III) a dissertation of the want of sense and knowledge in brute animals ... / written originally in Latin by the learned Anthony Le Grand ; now carefully translated from the last corrections, alterations, and large additions of the author, never yet published ... by Richard Blome.

CHAP. VII. Of Sound.

I. Liquid Bodies when dasht together, make a noise. SOund doth not only proceed from hard and solid Bodies, but also from fluid, and which because of the pliablness of their parts, do give way to the motions of other Bodies. For the Air, when it is struck, conveys a Sound to our Ears; the Waves when they dash against each other, cause a great noise; and all Waters, ac∣cording as they run through a plain Channel, or are interrupted with Rocks and Stones, make a different impression upon the Nerves.

The Reason is, because the parts of the Air, as well as of other liquid Bodies, by their beating against each other, become divided into innume∣rable small particles, which being most swiftly moved, and dashing against each other, must needs produce a Sound. For a Sound is nothing else but a trembling and waving motion of the Air: And as we see that by the throwing of a Stone into the water many Circles are formed, which uni∣formly extend themselves to the Shoar or Banks; so likewise the Sound that proceeds from Bodies that are struck, is by reciprocal vibrations propa∣gated through the Air.

II. How a Sound comes to be dispersed round. Which will more clearly appear in the Figure. Let there be supposed a String that is struck, which may be conceived as a Cylinder, whereof the semisection will make an half Circle, MBR, so as that whilst it restores it self, every one of its points are moved with a strait motion, and by parallel Lines, as AB, PC, OD, NE, MF, Let us then suppose in the several points of this Section some particles of pure Air, or Moisture, which may be considered as Globuli, or small * 1.1round Bodies L, K, I, H, G, &c. which touch the Section in the points BCDEF: Now if right Lines be drawn from the Center A, through the foresaid points, they will terminate in the Centers of the Globuli; and if one Globe fall upon another, it will move the same by a Line joining the Centers of both together: So that the Arc MB, of the Section of the Circle, diffuseth that most light matter according to the Angle MAB, and in like manner the Arc BR, according to the Angle BAR.

III. Why the Breath that is sent out of our Lungs is not heard. Thus we observe that our Breath, when gently sent forth from our Lungs, is not heard, nor when it is easily blown through a Pipe, because there are none of those frequent wavings, between the sides of the VVind-Pipe and the Pipe, which are necessary to convey the stroaks of them to the Organ. In like manner, as we see that a Hammer gently ap∣plied to the Anvil, doth produce no sound at all, because the Air is not sufficiently beaten back or undulated, as to produce that frequency of motion that may reach the Ear.

IV. Why Musi∣cal Instru∣ments are commonly hollow. Musical Instruments are commonly made hol∣low, and often approach to a Sphaerical Figure.

The Reason is, because the passing and repas∣sing percussions of the Air, are multiplied in a Hollow, and therefore do the longer detain and please the Ear. For in hollow Bodies, not only the outward Air is agitated by frequent concussi∣ons, but also the Internal. The depth also of Musical Instruments is of great use, because then Sounds are the better mingled in them, and one part being agitated, doth more easily make the other parts partaker of the Motion.

V. The make of the In∣strument, and the Place, do conduce to the variety of Sounds. Thus Hawk-bells, by reason of the slit and holes they have on their sides, do yield a greater Sound, than when in the open Air we strike upon any Brass Vessel; because the Sound of the Bell being pent up within the sides of it, doth break forth whole and strong. And it is for the same reason, that Musick within doors in cold weather is more agreeable, because then the Strings or VVood of the Instruments are more wrinkled, as it were, and become more hollow and porous. And on the other hand it is observed, that the Sound of Musical Instruments is not so distinct in Chambers that are hung, as in those that are VVainscotted, because the Sound doth more briskly rebound from a smooth and hard body, than from that which is soft and yielding. For indeed all soft Bo∣dies are less fit for the generation of Sounds, and do easily transmit them. And it is for the same Reason, that the Sound of hot Iron is more dull, than that which is cold, even because it is more soft, and the parts of this latter do yield more frequent vibrations.

VI. What is the Reason that a Deaf Man can per∣ceive the Sound of a Lute, whilst he holds his Teeth upon the Neck of it. A person that is Deaf may perceive the Sound of a Lute, or any other Instrument, whilst he holds the Neck of it between his Teeth.

Some have conceived that this is to be attribu∣ted to some conveyances, reaching from the Mouth to the Ears, which carry the Sound thither, and impress the same affection upon them, which is transmitted by the Organ of Hearing. But that this is not so, is apparent, because the same effect doth not follow when we hold our Mouth open. Besides, if this were sufficient, why might not sounds be perceived by the touch of the Forehead or Nose; seeing that from these parts there be pas∣sages to the Ears, and an equal communication between them?

Conclude we therefore, that the Sound of a Lute can therefore be heard or perceived by those who hold the Neck of it between their Teeth, because the vibrations of the Strings being trans∣mitted

[illustration]

[illustration]

Book. 2. Part. 2. Chap. 7.

G Freman. Inv.

I. Kip Sculp

from the Lute to the Teeth, are from thence communicated to the Membran that covers the sockets of the Teeth, and presently after shaking the Drum of the Ear, by means of the shut up Air, do also agitate the Connexion or Chain of the 3 little Bones. For a Body is then properly said to yield a sound, when being struck, it per∣forms several Vibrations by a tremulous motion, which by the Vehicle of the Air is diffused through the Bodies that are between the sounding Object and the Organ. For there is a consent betwixt the Nerves, which are disperst throughout the inward parts of the Mouth, and those which run through the Muscles of the Ear. An Argument whereof is, that harsh and grating Sounds, do stupifie and signally afflict the Teeth.

VII. Why a grating, skreaking Noise is very offen∣sive to the Ears. But of all Sounds, none are more ungrateful to the Ear, and indeed intolerable, than the skreaking Noise of a Saw, or the filing of Iron.

The Reason whereof is, because the particles of the Air, which strike against the Ear, do, because of their irregular figure, too violently vellicate the fibres of the Auditory Nerves, so as that thereby they are in danger of being broken, and sometimes break actually, whence that trou∣blesom and painful Sensation doth arise. The same also, tho' in a less degree, is caused by the hearing of false Tones, which is extreamly offen∣sive to a Musical Ear. And accordingly, by means of the foresaid Sounds the Teeth are sometimes set on edge; forasmuch as by this inordinate undu∣lation of the Air, the Nervous fibres which are at the Root of the Teeth, are in a manner loosed and separated from their former stability.

VIII. What is the Reason why, when the one of two Unison Strings are struck, the other trembles. If 2 Lutes or Citterns, whose strings are made Unison, are placed at some distance from each other, when the strings of the one are smartly struck, those of the other tremble also, and that so strongly, that they will shake off a bit of Paper laid upon them.

The Reason is, because the string being struck by a certain number of Vibrations, shakes the Air, which lighting upon the Unison strings of the other Instrument, doth shake it likewise. And this more especially, if the said strings be consonant in an Eighth or Fifth, for then their Vibrations will be less confused, and agree in their certain and frequent Intervals. For in an Eighth, all the Vibrations of a more lax and longer Chord or String, agree with a Second, Fourth and Fifth of a more stretched and shorter Chord; in a Fifth, with a Third, Sixth and Ninth, and so of the rest.

Wherefore this Trembling motion never follows where two Strings are differently tuned: Whereas Concords do not only excite each other, but others also, by reason of the similitude of their motions, and do so assist each other, as mutually to impart the same Affections. As may be experienced in any Musical Instrument.

IX. Whether there be such a thing as white Gunpow∣der, where∣by Guns may be discharged without Noise. It is a common Report amongst the many, that there is a White Gunpowder, with which Guns may be discharged without giving any Re∣port.

This, tho' very confidently asserted, appears to be a meer figment. For it is impossible that the pent up Air should be able to break forth without making a Noise: For that which is of such a force as to be able to drive a Bullet with as great swift∣ness, as the Flame breaks forth from the Gun∣powder, must needs strike the Air with a like force, and consequently produce an answerable Sound.

X. Why Men and Birds only can give forth Musical Sounds. Of all Animals, Men and Birds only are able to make Musical Sounds.

The Reason hereof must be fetch'd from the structure of the Throat and Wind-pipe, the Rings whereof in Men and Birds are capable of being contracted and extended. For there is a double recurring Nerve in the Wind-pipe, which turning round about it, doth by the help of some of its Branches move the Rings of it downwards; and forasmuch as the same is terminated in the Nerve, proceeding from the Plexus Ganglioformis, it moves the folds of the Wind-pipe upwards. So that whilst the Rings of the Wind-pipe, by means of the recurrent Nerve, are moved downwards, it causeth a deep or bass Tone; which becomes more high and shrill, when the said Rings are raised higher by the Branches of the 6th pair of Nerves, disseminated in the Wind-pipe; because the Wine-pipe being strained by this means, doth in a manner break the Sound that passeth through it.

XI. The Smoak of a Can∣dle, is agi∣tated by the motion of the Strings of a Musical Instrument. If a Lute be play'd upon near a Smoaking-Candle, the same motion of the Strings will be communicated to the Smoak.

The Reason hereof is, because the trembling Vibrations of the Strings do move the fluctuating Air, by the reiterated onsets whereof, the Flame (which of it self is very moveable) begins to be shaken, and to conform it self to the motions of the Strings. Hence it is, that when a Ray of the Sun is let in into a dark Room, and a Musical Instrument be plaid upon near the said Ray or Sun-beam, the Motes in the Sun will be seen to leap and skip in the Air, and, as it were, to dance to the Musick of the Instrument. The same may be also observed in the Water, when the Surface of it is very smooth and even; for then upon the Noise of stringed Instruments, it will become ruffled and curled. The same also may be ob∣served in 2 Glasses, into which if we put water to the height of 1 or 2 Fingers breadth, and bring them to an Unison, (which may be easily done by the Ear, in drawing our Finger round the Edge of them;) for then, if we fix a Crooked-Pin upon the Brim of one of the Glasses, we shall see it move and skip, as we press the Brim of the other Glass with our Fingers.

XII. Tones, or Musical Sounds, are not so proper to cause sleep, as some other Na∣tural sounds. Musical Sounds are not so conducive to provoke Sleep; as the Humming of Bees, the Noise of the Wind, the Murmur of Running-water, and an equal and smooth Tone of Reading.

For seeing that the Sound is diffused from the Sonorous Body to the Drum of the Ear, and from thence to the Acoustick Nerve, and so to the Brain, the Center of the Nerves, and last of all from thence to the Arteries, Veins and Guts, it cannot be but that the Blood and the Spirits must be moved also: And because Musical Sounds are not carried with an Equal Course, nor do pass by the Ears, they do affect the Sense of Hearing more than other Sounds, and more awake the Attention, which is the reason that they are not so fit for the provoking of Sleep.

XIII. Musick corrupts Manners. Long Experience hath taught, that soft and Effeminate strains of Musick, are very proper to corrupt the Manners of men: Whereas, on the other hand, the Sound of Cornet, Trumpets and Drums, do fill Men with a Couragious and War like Spirit.

For seeing that Human Affections are nothing but Sensations, produced by the motion of the Spirits, we need not wonder that the Sound arri∣ving at those Vessels in which the Passions are ge∣nerated, should produce various Passions. And forasmuch as the Manners of Men commonly follow their Passions, it is evident that Sounds must needs be of great use, either for the corrupting or correcting of Mens Manners. Accordingly PLA∣TO was of Opinion, that all soft Tunes ought to be banished out of a well-governed City. And the Lacedaemonians assign'd a great Punishment to those that used any soft or effeminate kind of Musick; and made a Law, that none should play upon a Harp that had above 7 strings.

XIV. Why upon the stop∣ping of our Ear, we hear a kind of humming Noise. When we stop our Ear with our Finger, we suddenly hear a buzzing kind of Noise.

Because it is owned by Physicians, that a Steam or Vapour, doth proceed out of the Hollow∣winding of the Ear; so that when the Ear is stopt, this pent up Steam, as well as the Air, seeking to get out, do beat and distend the Drum of the Ear; from which Motion, an Affection is produced like to a great Buzzing. Yea, it is frequently found, that the Ears, tho' not stopt by our Finger, are fill'd with this Buzzing Noise, produced by the blast of a most thin Steam or Vapour breaking forth from some little Artery or Vein, which striking against the Drum of the Ear, affects it much in the same manner, as it would be by the sound of a Bell.

XV. Sound more easily passeth through a Beam of Wood, than through the Air. A Sound is more easily diffused through the length of a Beam, struck at one end, than through the Air only. For as soon as one end of the Beam is moved, in the same instant the motion is communicated to the other.

The Reason is, because there is a greater Con∣tinuity of Parts in the Beam, than in the Ai••. For, when you move one end of the Beam A, at the same time the other B is moved also; but if you push the Air at C, it must at least move as far as D, before it can move E, because all its parts give way like a Sponge; and because it takes up * 1.2some time in passing from C to D, it loseth also part of its Force. Whence it comes to pass, that the Sound, which is nothing else but a motion of the Air, is both sooner and more strongly heard at the Point D, than at the Point E.

XVI. Why Sounds are more clear∣ly and distinctly heard near the Banks of Rivers. Which is the Reason why the sounds of Great Guns and Bells, are more distinctly perceived along the Banks of Rivers, than when we are at a distance from them; and it is universally true, that all and every sound is both sooner, and at a greater distance, communicated by water; for the parts of the water being more close and stiff than those of the Air, when once put in motion, do com∣municate their Force to others. To this moreover may be added, the smooth surface of the water▪ which doth not in the least break or turn aside the sound. Thus by laying our Ear to the ground, we can perceive the trampling of Horses at a great distance; and if a Drum be set upon the Ground, and the Ear laid to the upper Skin of it, the Noise of the marching of Horses can be per∣ceived at some Miles distance.

XVII. How the Voice of one man comes to be diffused to the Ears of so many. The Voice of a Preacher in a Church, or Actor upon a Stage, reacheth the Ears of some Thou∣sands of his Hearers.

This is not, because the whole Voice of one man comes to the Ears of all that hear him; for the Voice, as soon as it comes forth out of the Mouth, is broken into many parcels all like the whole; much in like manner as when Fullers spout out water out of their Mouths; for then the water is dispersed into innumerable drops, and fills a very large space. From the Mouth of the Speaker an entire Voice doth indeed proceed; but is afterwards divided into innumerable Voices: And therefore sure it is, that no two Auditors receive the same Voice, tho' they be said to hear the same, because of the likeness of these divided partial Voices, with the entire or total Voice. In the same sense, as they are said to drink the same Liquor, who drink out of the same Foun∣tain.

XVIII. Sounds are diffused along some certain Tract or Currents, more than others. Tho' Experience shews, that the whole Atmo∣sphere of the sonorous Body, is moved to such a proportionate Circumference; yet is not the said fluctuation of the Air equally diffused through all parts of the Air, but the sound seems rather to be carried along some certain Tracts or Cur∣rents. And therefore it is that the Words of a Preacher or Oratour, tho' they move the whole Atmosphere of the Auditory; yet it agitates that Tract most which his Mouth more directly answers to, where the Auditors do also more di∣stinctly hear his Voice, than those who are more remote from that Tract. Thus it is well known, that those only hear the hissing Noise of a Bullet, discharg'd from a Musquet, who are near to the Line described by the Bullet, whilst those who are at some distance perceive nothing of it.

XIX. Sounds are equally diffused. Sounds that are excited in any one place, be they Loud or Low, are in equal time conveighed to the place, where they are heard.

The Reason is, because the Air being a Conti∣nuous Body, when struck, is formed into Orbs or Circles: As we see that still-water, when a Stone is cast into it, becomes waved into Circles; and as the said Circles, at an Equal distance, spread themselves to the Banks, whether they be caused by a little or great Stone; so likewise doth the sound, at an equal distance of Time, come to the Ear, whether it proceed from a great Gun, or a Musquet, or any other thing.

XX. Whence it is that a double Sound is perceived from the striking of one String. It sometimes happens, that 2 Sounds are heard, when one only string is struck.

This proceeds from some defect in the string, which when they are false and uneven do admit 2 several kind of shakings at one and the same time, whereof the one, and which gives the deeper sound, proceeds from the whole string; the other, which affords a more shrill sound, depends on the unevenness of the string. Suppose, for Example, that when the string A B is struck, as often as it passeth and repasseth from 1 to 6, to produce its Natural sound, at the same time the Unevenness * 1.3of its parts produce another shaking in it, by means whereof, when it hath moved from 1 to 2, it runs back to 3, and from thence towards 4, and from 4 to 5, and lastly to 6, which produceth a sound that is by a Twelfth more shrill than the

former: In like manner, if the second shaking be only double to the former, it will yield an Eighth; if Quadruple, a Fifth; and if Quintuple, a Seven∣teenth more than before.

XXI. Why we see the Lightning before we hear the Thunder. A Sound takes more time to arrive at our Ears, than the Light to come to our Eyes; which is the Reason why we perceive the Lightning before we hear the Thunder; and we see the Ax of one that hews Timber, when we are at some considerable distance, lifted up to make a second stroke, before we hear the first.

The Cause whereof is the Air, which altho' it consist of subtil parts, and divided from each other; yet being withal Branchy and flexible, when one of them is moved, the other parts are not presently moved at the same instance, but by degrees; so as that one part being agitated, pusheth on the next, and so on; like the Circles in the Water, which do not in an instant spread them∣selves over the whole surface of it, but proceed in a continual order till they come to the Banks of the River, or that they cease upon the failing of the force, which caused them at first. But Light is much more swiftly conveighed to our Eyes, as being caused by inflexible and solid Globuli. For it is the Nature of solid Bodies, that when one end of them is prest upon, the said pression is felt at the same moment of time, at the other end of it. Whence it is that, as was said before, a Sound is sooner conveighed through a whole Beam, than through the Air; because the parts of the Beam are more closely joyned together, than the parts of the Air, which are flexible, and easily give way to other Bodies.

XXII. Strings of an unequal length, yield a different sound. Let there be 2 Strings of the same thickness, and wound-up at the same height, whereof the one is longer than the other; that which is the shorter of the two will yeild the shrillest, or most treble sound; and the longer, the deeper sound and less perceptible.

This difference of the Sound proceeds from the more frequent, or fewer Vibrations of the said strings: For seeing that a shorter String makes more wavings, and beats the Air with more re∣iterated stroaks, by so much shriller is its sound, and the sooner it conveighs the sound to the Ear. Because the difference of a deep and shrill sound, doth not proceed from the more swift or slow motion of a string, as ARISTOTLE was of Opinion, but from the variety of the Vibrations, which, if they be frequent, produce a treble or shrill sound; but if fewer, are the cause of a deep or bass sound.

XXIII. In like manner we may give an account, why the lesser of 2 strings that are wound-up alike, but of different length, makes its Vibrations more swiftly. The Reason is, because tho' both the strings make their Excursions with an Equal mo∣tion, with respect to Space and Time; yet because the lesser, by its motion of Contraction, runs through a less space than the longer; and that a less Space is sooner run through with an Equal motion than a Greater, it must needs be that the motion of the Lesser Cord be swifter.

Why the Sound ceaseth upon touch∣ing the Strings with ones Finger. Whence it is evident, that if you lay your Fin∣ger upon a String presently after you have struck it, before it have made many of its Vibrations, you will indeed hear some kind of Noise, but without being able to distinguish whether it be shrill or deep, because your Finger hinders the Vibrations, and doth not suffer the string by its pression to dilate the Air, and to drive it away by a successive beating of it. Hence it is that a slow and soft blast, blown into a Pipe, produceth no sound, nor that which from the Lungs is breathed out by the Mouth; because there is no rebounding of the Air, between the sides of a Pipe, nor in the Wind-pipe or Mouth of an Animal, which bound∣ing this way and that way, is the cause of a sound; and according as their Repetitions are more swift or slow, so they produce either a shrill or deep sound.

XXIV. Why the Eccho re∣peats the same Voice several times. An Eccho doth frequently repeat the same Voice, and renders the same sound at distinct Intervals. So CLAUDIAN makes mention of one that rendred the Voice no less than 7 times: And GASSENDUS tells us, that he had Experi∣enced, that in the Chapel of Charenton, which is about 3 or 4 Miles distant from Paris, one Syllable pronounced at either end of it, was repeated 17 times, and that the same word spoken in the midst of it, was as many times repeated from both Sides.

The Cause of this is, the Reflection of the Sound from some interposed let or hindrance: For as innumerable Rays are conveighed from the visible Object, not only to the Eye, but every way round; so besides the Voice which is carried to the Ear, innumerable other sounds are dispersed in the Air, which meeting with hard and concave Bodies, are dispersed through the Air, which makes the same Voice to rebound several times. For Sound is not conveighed like the Light, in one moment, but stands in need of time, to propagate it self: And therefore when the former sound becomes extinct, or vanisheth in the neighbouring Air, another is generated in that which is farther off; which being reflected from solid and tolerably smooth Bodies, doth frequently beat the Air that is nearer the Ear. A Sound therefore is often∣times repeated by the Eccho in the Chapel at Cha∣renton; because the place there is so disposed, that the nearer places do first repeat the Voices, and the more distant afterwards. It conduceth also to the forming of an Eccho, that the Bodies which reflect the Sound be opposite to each other, and send back the same by turns; as it was in the Chapel at Charenton, before that the Monastery of the Car∣melites was built there: For at that time there was a double Row of Pillars, between which the uttered Voice was rebounded; much like a Ball, which lighting against one Wall, rebounds thence to the other.

XXV. Why the Eccho is heard only in one part. Tho' the Eccho be a Sound which is every way circularly extended, yet can it only be heard in one part of the Circle; because it can only be received from the Reflexion of that part of the Circles, which is the farthest extended; and in that part where the said Reflexion is made. As we observe, that when a Stone is cast into a River, the Circles which are there formed; are further extended towards that part, where the Stone was cast in, than towards the opposite.

XXVI. A reflected Sound is of longer continu∣ance, than one that is not reflected. A Sound that hath been frequently rebounded, is preserved or continued a longer time, than that which without repercussion is propagated in a Right line.

The Reason is, because by the several Bodies and Cavities against which the Repercussion is

made, the sound is strengthned and increased, and therefore is longer a vanishing, than if it were only extended in a Strait line, without reper∣cussion. Moreover, it is evident from the Obser∣vations of many, that in the Village of Simonetta, about a mile distant from Milan, the Voice is often repeated 30 times, and in every one of its passings and repassings, it runs through 156 Paces and upwards; whence it follows, that the same Voice being separated 32 times, before it be altogether extingu••••ht, must run through 5002 Paces and upward. From whence it may be easily gathered, that the sound must needs be greatly increased in the said Concamerations, by means whereof it is enabled to continue so long, seeing it doth not seem possible, that by continual direct Motion, a sound should be able to reach 5 Miles, in which motion of the sound 25 Horary minutes must be spent.

XXVII. A Sound is hindred by the Inter∣position of a solid Body. When a Man speaks to another, a thick Glass Window being between them, his Voice will scarcely be heard; but if there be only a Paper Window between them, the Voice may be well enough discerned.

The Reason is, because the sound is an effect of the motion of the Air, and therefore because little or no Air can pass through the pores of the Glass, the Organ of Hearing cannot be affected thereby. Forasmuch as the Intervening Glass is supposed to be so firm, that it is not capable of being shaken by the sound; whereas the Air easily passeth through the pores of Paper, especially if the same be stretched, because by this means it is the more easily shaken, and its pores are made more lax and open.

XXVIII. A Bell when struck on the upper part of it, yields a shriller sound, than when hit lower. A Bell yields a more shrill sound when struck on the upper part of it, than when it is hit Lower.

The Reason is, because the hollowness con∣duceth to the Deepness of a sound; and because the further that the sound is propagated the more Bass or deep it is. Thus the lower Holes of a Recorder afford a deeper sound; for the slower the beating of the Air is, the deeper is the sound. As we find that the more water there is in a Glass, when we press our Finger round the Edge of it, the more shrill the sound is, for then the Vibra∣tion of the Air is the swifter, as when less water is in the Glass, so much the more deep the sound is.

XXIX. How it comes to pass, that Glass may be broken by a Voice or sound. It is observed, that a Drinking Glass may be broken by a man's Voice only, and that by reason of the repeated Vibrations of the parts of a more solid Body. For the effecting whereof, first, we must try by a stroak with our Finger, what Tone the parts of the Glass do yield, and then must set our Voice as near as we can to the same Tone, and increase the same by degrees, till we come beyond a Diapazon or Eighth: Whereupon the insensible parts of the Glass being struck with iterated stroaks, become agitated by a tremulous motion, which increaseth as they are struck in fit places, so that at last, by the augmentation of the force of the sound, the parts of the Glass leap asunder. But for this Experiment, a smooth and even Glass must be made choice of, and such as when filipt with the Finger doth not sound so shrill, but that the Voice of him that sings, may equal it, or go beyond it.

XXX. Why a Sound can sometimes be better heard by one that is a•• a distance, than by him that is nearer. Sir KENELM DIGBY relates in his Treatise of Bodies, that he had seen the Walls of a large and round Tower (tho' I rather suppose it to have been of an Elliptical figure) which were so Artificially built, that 2 men standing at the opposite points of the Diameter, might easily and distinctly talk together, whilst those that stood in the midst, could not perceive the least of any thing that was spoken.

The Reason of this must be fetched from the Coition or meeting of all the sounds, which are dispersed through the whole Room: For seeing that all the Air in the Room is shaken by the uttered Voice, the motions thereof being diffused through that large Space, are reflected from the Wall of an Elliptical figure, and so by Reflexion become united in the uttermost part of the Cham∣ber; and therefore he that lays his Ear, must needs hear the Voice of him that speaks at the other end, tho' with a very Low Voice.

XXXI. How a Sound be∣comes in∣creased by the means of a Pipe. Upon the same account it is, that by means of a Pipe, contracted in manner of a Cone, sounds may be increased, and made to be heard further off, better than nearer hand; and this, because the sound is increased proportionably, as the Tube is contracted; for by this means the sound must needs be increased in its passage through the Pipe. And accordingly they who are Deaf, make use of a Horn, whereof the one end is wider than the other, which they apply to their Ear, by it to receive the Voice of him that speaks to them. And by this means, a Prince might easily hear the Voices of those that walk in his Garden, by having Pipes conveyed from thence to his Closet, the widest Mouths of them being set outward, and the narrowest inward.

XXXII. How a Sound comes to be propagated at that great di∣stance by the Stente∣rophonick Tube. The Stenterophonick Tube, sometime since In∣vented by Sir SAMUEL MORELAND, which carries the Voice to the distance of a Mile or two; and that other Trumpet, which ALEX∣ANDER the Great made use of, in giving Orders to his Army; whereof the Figure is to be seen in an Ancient Manuscript of the Vatican Library, are made after another manner; for they are streight or narrow at the Mouth, to the end that the particles, which are to make the Reflexion, being close together, may be the more easily beaten, and from thence the Trumpet grows wider and wider to the very end of it, in order to augment the agitation of the Air, by the multiplication of all the Reflexions which are made throughout the whole length thereof; yet with this Circumstance, that the Bore of the Pipe might be so great, and the Trumpet so long, that the sound would be no longer increased, because the Reflexions would become so weak, as not to be longer in a condition to move the particles of the Trumpet, and consequently cause a new Re∣flexion.

XXXIII. Why bees, when they swarm, are recall'd by making of a Noise. Swarming Bees are recalled by beating upon Frying-pans and Sithes.

Some suppose the cause hereof to be, because Bees are delighted with these Noises, and being thereby allured, do all unite themselves in one great hanging Bunch or Cluster. But this is not at all probable, because when the Bees are got up into any height of the Air, how much soever the said Instruments may be beaten, this will not bring them down, or hinder them from flying away.

Wherefore the true Cause hereof seems to be, be∣cause the Air being much shaken, and agitated with the Sound, the Bees not being able to bear the same, are forced to unite themselves and settle in a heap. For Bees have very thin VVings, not feathered ones like Birds, but consisting of a thin Skin; by means whereof they cannot endure this concussion of the Air: Which probably also is the reason, why they never leave their Hives when there is a great VVind, or at Midnight, but only in calm and hot weather.

Notes

• * 1.1

  Figure 8.
• * 1.2

  Figure 9.
• * 1.3

  Figure 10.