Page:Cyclopaedia, Chambers - Volume 2.djvu/984

 V O I ( 327 )

Hence, as (he Depth of the Tone of a Hautboy is an- fwerable to the Length of the Inftrument -; the longeft Fi- bres of the Wood, whofe Vibrations make the Refonance, making always the floweft Vibrations, and confcquently the deepeft Tone : It may appear probable, that the Concavity of the Mouth, by its lengthening for grave Tones, and Shortening for acute ones, might ferve very well for the Pto- duclion of the divers Tones : but M. Tlodan obferves, that in that play of the Organ call'd the human Voice, the loneeft Pipe " ■

v o I

is preci!

Mouth of a Man of the grav'eft Voice, not "being above fix Inches deep ; 'tis evident that can't modify, varv and give the Tone. See Tune. " " a

'Tis the Glottis, then, that forms the Tone, as well as the Sound ; and the manner of forming the various Tones, is by varying its Aperture.— A piece of Mechanifm too ad- mirable not to be here particularly inquir'd into.

The human Glottis, then, reprefented in Tab. Nat. Hif-

degrees of Approach. Thefe different Apertures of the

Glottis, Anatomifts ufually attribute to the Aflion of the Mufcles of the Larynx ; but M. Hodart thews, from their Pofition, Direaion, Sfc. that they have other f'fes ; and that the opening and /hutting of the Glottis is effeflcd by other means, viz. by two tendinous Cords, or Strings, inclo- fed in the two Lips of that Aperture.

In effeft, each of the two femicircular Membranes whofe Interftice forms the Glottis, is doubled back upon it felt; and within each Duplicature is a Chord or String, which is faflen'd at one End to the fore-part of the Larynx,

and to the hind-part at the other. 'Tis true, they appear

more like Ligaments than Mufcles ; as confiding of white and membranous Fibres, not of red and flefhy ones : But the vaft Number of minute Changes in this Aperture, necef- fary to form the vaft Variety of Tones, make an extraordi- nary kind of Mufcle, by whofe Contraction they fhould be effected, abfolutely neceflary. Common flefhy Fibres, wherein the Blood is receiv'd in large quantity, had been in- finitely too coarfe for fuch delicate Motions.

Thefe Strings, which in their State of Relaxation make each a little Arch of an Elliplis ; as they contract more and more, become longer, but lefs and lefs curve ; and at latt, with the greateft Contraction they are capable of, degenerate' into two right Lines applied clofe to each other ; fo clofe and fo firm, that an Atom of Air can't efcape out of the Lungs, how full foever they may be, and how great an Ef- fort foever all the Mufcles of the lower Venter may make againft the Diaphragm, and by the Diaphragm againft thefe two little Mufcles.

The different Apertures of the Lips of the Glottis, then, produce all the different Tones in the fix Parts of Mufick, ■viz. Safs, Common pitch, Tenor, Counter-tenor, Treble-Safs, and Treble ; and the Manner is thus :

The Voice, we have Ihewn, can only be form'd by the Glottis ; but the Tones of the Voice are Modifications of the Voice ; and can only be produced by the Modifications of the Glottis.— Now the Glottis is only capable of one Modification, which is, the mutual Approach or Recefs of its Lips : 'Tis this, therefore, produces the different Tones. — Now that Mo- dification includes two Circumftances : the firft, and princi- pal, is, that the Lips are ftretch'd more and more, from the loweft Tone to the higheft ; the fecond is, that the more they are ftretch'd, the nearer they approach.

From the firft it follows, that their Vibrations will be fo much the quicker, as they come nearer their higheft Tone ; and that the Voice will be juft when the two Lips are equal- ly ftretch'd, and falfe when unequally ; which agrees per- fectly well with the Nature of String Inftruments.

From the fecond it follows, that the higher the Tones are, the nearer will they approach each other ; which agrees lerfectly well with Wind Inftruments, govern'd by Reeds, or

ugs.

The Degrees of Tenfion of the Lips, are the firft and principal Caufe of Tones ; but their Differences are infenfi- ble. — The degrees of Approach, are only Confequences of that Tenfion ; but their Differences are more eafily affign'd.

To give a precife Idea of the thing, therefore, we had beft keep to that ; and fay, that this Modification confifts in a Tenfion, from whence refults a very numerous Subdivision of a very fmall Interval ; which yet, fmall as it is, is capa- ble, phyfically fpeaking, of being fubdivided infinitely. See Divisibility.

This Doctrine is confirm'd from the different Apertures found in diffecting Perfons of different Ages of both Sexes. — The Aperture is lefs, and the exterior Canal always fhal- lower in the Sex and Ages fitteft to fing Treble. — Add, that the Reed of a Hautboy, feparated from the Body of the

I

Inftrument, being a little prefs'd between the tips, wili ,ie r,j Tmre fimiewhat higher than its namral and J

P kT », more ' wi " yidd another fli11 higher : And thus an able Mufician may run fuccefiively thro' all the Tones and Semitones of an Octave.

'Tis different Apertures, then, that produce, or at leaft ac- company different Tones, both in Natural Wind Inftruments, and Artificial ones ; and the Diminution of the Aperture, raifes the Tones both of the Glottis and the Reed.

The Reafon why leffening the Aperture heightens the Tone, is, that the Wind paffes thro' it with the greater Ve- locity; and from the fame Caufe it is, that if any Reed, or Plug of an Inftrument be too weakly blown, its Tone will be lower than ordinary.

Indeed, the Contraftions and Dilatations of the Glottis, muft be infinitely delicate : By an exact Calculation of the ingenious Author abovemention'd, it appears, that to per- form all the Tones and Semitones of a common Voice, which is computed to reach to 12 Tones to perform all the Par- ticles and Subdivifions of thofe Tones, into Commas and other minuter thoftill fenfible Parts ; to perform all the Shades, or the Differences in a Tone when founded more or lefs ftrong, without changing the Tone : the little Diameter of the Glottis, which does not exceed f f of an Inch, but which varies within that Extent at every Change, muft bs actually divided into 9(132 Parts ; which Parts are yet very unequal, and therefore many of 'em much lefs than the ?¥fT— Part of an Inch. — A Delicacy fcarce to be match'd by any thing but a good Ear, which has fo juft a Scnfe of Sounds, as, naked, to perceive Differences in all thefe Tones ; even thofe whofe Origin is much lefs than the o6~3200tb. Part of an Inch. See Hearing.

Voice, in Grammar, is a Circumftance in Verbs, where- by they come to be confider'd as either aSive or pajjive, i. e. either as expreffing an Action imprefs'd on another Sub- ject, as / beat ; or receiving it from another, as I am beaten. See Verb; fee alio Active, and Passive.

Voice, in Matters of Elections, denotes a Vote, or Suf- frage. Sec Vote, S?c.

In this Senfe, a Man is faid to have a deliberate Voice, when he has a Right to give his Advice and Opinion in a Matter of debate, and his Suffrage is taken — An attivc Voice, when he gives his Vote for the Election of any one } and a pajjive Voice, when the Suffrages may fall on him to be elected — An excitative Voice, when he may act to pro- cure another_to be elected — A confldtative Voice, when ho can only offer Reafons and Remonftrances, whereon the Chief or Head determines at his own Difcretion : Such the Cardinals have, with regard to the Pope ; the Mailers of Chancery, with regard to the Lord Chancellor, ?£c.

VOID Space, in Phyficks. See Vacoom.

Void, in Common Law. See Annulling.

VOIDANCE, Vacancy, in the Canon Law, a Want of an Incumbent upon a Benefice. See Vacancy, &c.

This is twofold, cither in Law, de Jure ; as when one holds fevetal Benefices that are incompatible : or de Fatlo, infDeed; as when the Incumbent is dead, or actually de- priv'd:

VOIDED, Uuide, in Heraldry, is underftood of an Or- dinary whofe inner or middle Part is cut out ; leaving nothing but its Edges to fliow its Form ; fo that the Field appears thro' it.

Hence it is needlefs to exprefs the Colour or Metal of the voided Part ; becaufe it muft of courfe be that of the Field.

Thus, the Crofi voided differs from the Ctofs fimbriated, in that this latter does not (hew the Field thro' it, as the other does. — And the fame is ufed in other Ordinaries.

VOIDER, in Heraldry, one of the Ordi- naries, whofe Figure is much like that of the Flafque, orFlanch; only that it doth not bend fo much. See Flancii.

This Armoury, they fay, is properly the Reward of a Gentlewoman that has well ferved her Prince. — It is always born by Pairs.

VOIDING, in Medicine. See Evacuation.

In the ^Philosophical TranfaBiom, we have an account of one Matt. Milford, who voided a Worm by Urine, fuppofed to have come from the Kidneys. See Worms.

Dr. Lifter mentions true Caterpillars voided by a Boy of nine Years old. — Mr. Jejfof faw Hexapods vomited up by a Girl.

Catherina Geilaria, who dy'd in 1661, in the Hofpital of Altenburg, for 20 Years voided by Vomir and Stool, Toads, and Lizards. Ephem. German. T. I. Obf. 103.

In the fame Ephem. is an Inftance of a Kitten, bred in

the Stomach, and vomited up.' Of Whelps, Frogs, La~

certe Aquatics, and other Animals, bred the like way. —Sartboline gives us an Inftance of a Worm, bred in the Brain, and voided by the Nofe of 0. W. See Vermes.

VOIR Dire, in Law— When, upon a Trial at Law, it is prayed that a Witnefs may be fwotn upon a Voir dire ;

the