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From this Region of the Tympanum, I might país - : : : * * * · · · |- to

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the Braces of the War-drum do in that. And confidering how curious and folemn an Apparatus there is of Bones, Muscles, and Joynts, all'adapted to a ready Motion ; I am clearly of Dr. Willi's Opinion, that one great Ufe pf the Ear-drum is for the proportioning Sounds, and that by its Extenfion and Retraction it corres. ponds to all Sounds, loud or languid,, as the Pupil of the Eye doth to feveral Degrees of Light : and that they are no other than fecondary Ufes affigned by Dr. Schelhammer, as the principal or fole Ufes; of keeping out the external colder Air, Duft, and other Annoyances, but especially that ob folius aeris interni potifmim irrumpentis vim, hunc motum Tympani, ac Mallei esse conditum, ut cedere primùm, deinde fíbi refiitui queat ; as his Words are, P. ult, c. 6. §. 13. · - | 5 It was no improbable thought of Rohault, nos attentos prebere, mil aliud ef, mis Tympanum, ubi ita opus ef faćio, contendere aut laxare, & operam dare ut illud in ei positione intentum fiet, in quâ tremulam aeris externi motum commodifimè excipere possit. Roh, Phys. p. 1. c. 26, §. 48. - , . ' * The hearing of deaf Persons more eafily by means of loud Noises, is another Argument of the Ufe of the Straining or Relaxation of the Tympanum in Hearing. Thus, Dr. Willis (ubi fupra) Accepi olim à viro fide digno, mulierem novisse, que licet furda fuerit, quousque tamen intra conclave Tympanum pulsaretur, verba quævis clarè audiebat : quare Maritus ejus Tympaniffam pro fervo domefico conducebat, ut illius ope, colloquia interdum, cum Uxore fuå haberet. Etiam de alio Surdafro mibi narratum ef, qui prope Campanile degens, quoties unà plures campane refonarent, vocem quamvis facilè audire, & non aliàspotuit. Abfish Mufulo [Processus majoris Malleij in recenti aure, relaxatur [Tympani Membrana]. Valfalv. de Aur. Hum. c. 2, §. 5. « * * , \ • • • |- tipon confidering the great difference in Author's opinions about the Ufe of the Parts, and Manner how Hearing is pērformed, as also what a curious Provision there is made in the Ear, by the four little Bones, the Muscles, Membrane, &c. I was minded (fince I penned this Note) to make enquiry my felf into this Part, and not to rely upon Authority. And after a diligent fearch of various Subjects, I find we may give as rational and eafie an Account of Hearing, as of Seeing, or any other Sense ; as I have shewn in my laft cited Note 4. Book VII, C bap. 2. with relation to Birds, And as to Man and Beafts, the cafe is the fame, but the Apparatus more Complex and Magnificent. For whereas in Birds, the Auditory Nerve is affested by the Imprestions made on the Membrane, by only the intermediacy of the Collumella, in Man, it is done by the Intervention of the four little Bones, with the Muscles afting upon them ; his Hearing being to be adjusted to all kinds of Sounds, or Impresions made

upon

to that of the Labyrinth (21), and therein furvey the curious and admirable Strućture of the Vefiibulum, the Semicircular Canals (22), and Cochlea; particularly the artificial Gyrations, and other fingular Curiofities observable in the two latter. -

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upon the Membrana Tympani, which Impressions are împarted to the Auditory Nerve in this manner, viz. first they ast upon the Membrane and Malleus, the Malleus upon the Ineus, and the Incus upon the os orbiculare and Stapes ; and the stapes upon the Auditory Nerve: for the Bafe of the Stapes (the fame as the Operculum in Birds) not only covers the Fenefira Övalis, withín which the Auditory Nerve lieth, but hath a part of the Auditory Nerve spread upon it too. It is manifest that this is the true Process of Hearing, because, if the Membrane be moved, you may fee all the Bones move at the fame time, and work the Bafe of the stapes up and down in the Fenestra ovalis, as I shewed in this Chapter, wote 4. concerning the Mole ; and as it may be feen in other Ears carefully opened, if the Parts remain in fitu. (21) I do not confine the Labyrinh to the canales Semicireulares, or any other Part, as the elder Anatomifts feem to have done, who by their erroneous and blind Defcriptions feem not well to have understood thefe Parts : but with those much more curious and accurate Anatomifts Monfeur de Vernay, and Dr. Valfalva, under the Labyrinth, I comprehend the Canales Semicirculares, and the Cochlea, together with the intermediate Cavity, called by them the Pestibulum. (22) In the Semicírcular canals, two Things deserve to be noted. 1. That the three Canals are of three different Sizes, Major, Minor, and Minimus. 2. Although in different Subjects they are frequently different ; yet in the fame Subject they are confiantly the fame. The reafon of all which, together with their Ufes, Valfalva ingeniously thinks is, that as a part of the tender Auditory Nerve is lodged in these Canals, fo they are of three Sizes, the better to fuit all the Variety of Tones; fome of the Canals fuiting fome, and others, other Tones. And although there be fome difference as to the Length and Size of these Canals in different Persons; yet, left there should be any discord in the Auditory Organs of one and the fame Man, those Canals are always in exast Conformity to one another in one and the fame Man. V. Valfal, ubi fupr. c. 3. §. 7. and c. 6. §. 4, 9.

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But

i But I shall not expatiate on these recluse Parts, only there is one fpecial Contrivance of the Nerves ministering to this Senfe of Hearing, which muft not be passèd by ; and that is the Branches of one of the Auditory Nerves (23), fpread partly to the Muscles of the Ear, partly to the Eye, partly to the Tongue and İnftruments of Speech, and inofculated with the Nerves to go to the Heart and Breaft. By which means there is an admirable and useful Confent between these Parts of the Body ; it being natural formoft Animals upon the hearing any uncouth Sound, to erect their Fars, and prepare them to catch every Sound ; to open their Eyes (thofè conftant faithfül Sentinels) to ftand upon, their

Watch; and to be ready with the Mouth to call

out, or utter what the prefent Occafion fhall dićtate. And accordingly it is very ufual for moft Animals when furprized, and terrified with any frightful Noise, prefently to fhriek and cry out.

But there is befides this, in Man, another great Ufe of this nervous Commerce between thé Far and Mouth: and that is, (as one of the beft Authors on this Subject exprefieth it,) (24) “ That the Voice “ may correspond with the Hearing, and be a kind

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“ of Eccho thereof, that what is heard with one of

“ the two Nerves, may be readily exprefied with “the Voice, by the help of the other. ; : : :fi: Thus much shall suffice to have spoken concerning the Organ. Let US, : - . * - - . ' o 2. Take notice of the Objest of this admirable Senfe, namely Sound, and foconclude this Chapter, I fhall not here enquire into the Natúre and Properties of Sound, which is in a great measure intricate, and hath puzzelled the beft Naturalists: Neither íhall I fhew how this admirable Effećt of the Divine Contrivance may be improved to divers Ufes (25), and Purposes in humane Life But my Bufiness will be to fhew that this thing, of fo: - - II] 11:3 DIE

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(23) Among the Ufes to which the wit of Man hath employed Sounds, we may reckon the Instruments useful in convocating Assemblies, managing Armies, and many other Oceafions, whereîn Bells, Trumpers, Drums, Horns, and other founding Inftruments are used; the Particularities of which it would be tedious to recount, as that the biggest Bell in Europe is reckoned to be at Erfurt in Germany, which they fay may be heard twenty four Miles 5 with much more to the fame : - I fhalf therefore only for a Sample take notice of the Speaking-Trumpet ; the Invention of which is -commonly-afcribed -te -oar eminent Sir Samuel Morland ; but was more probably Ath. Kircher's, at leaft he had contrived fuch an Instrument, before Sir Samuel hit upon his. Kircher in his Phonurg faith, the Tromba published last Year in England, he had invented Twenty-four Years before, and published in his Mifurgia ; that fac. Albanus Ghibbestus, and Fr. Efchinardus afcribe it to him ; and that G. schottu testifieth he häd fuchan Instrument in his Chamber in the Roman College, with which he could call to, and receive Answers from the Porter. And confidering how famed Alexander the Great's Tube was, which is faid night be heard 1oo Stadia, it is fomewhat frange that no body fooner hit upon the Invention. Of this stentorophonick Horn of Alexander, there is a Figure preferved in the Vatican ; which for Curiofity fake, I have from Kircher represented in Fig. 3. . He faith its Diameter was five Cubits, and that it was fuspended on a Supporter. - * - For

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