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Mr. URBAN,

Nov. 4. any other body in contact with our HAD an opportunity, during the ear. The ear, being affected by this

last summer, of visiting the fine motion, transmits the impression to monastic ruins of Rievaulx in York- the brain. In this manner we exershire, and can bear testimony to the cise the sense of hearing.” accuraey of the description given in "Upon examining lhe organs of the Supplement to the First Part of hearing,” says Mr. Cuvier, in all your Vol. LXXX. I beg leave to animals in which that sense has been send you a Drawing, representing the discovered, the only part constantly North-east View of the Abbey. existing is a gelatinous pulp, which is Yours, &c.

J. C. B.

covered by a fine elastic membrane,

and in which the ramifications of the Mr. URBAN,

Feb. 1. auditory are lost: this pulp fills the of correcting a prelimmary error the cuttle-fish.” in my last communication; which “We may form a very natural idea does not, however, render it less in- of the connexion of this substance trinsically valuable:

with the external movements which The Letter of Bp. Atterbury had are the cause of sound: this quiverbeen printed in the (now very scarce) ing jelly will receive, with facility, Fifth Volume of that learned Prelate's the concussion transmitted to it by

Epistolary Correspondence, 1798," the vibrations of sonorous bodies, p. 175. Mr. Taylor, to whom it is and communicate them to the brain. addressed, was Clerk to Bridewell Thus far the motion can be traced : Hospital; and was the Bishop's but the process which is afterwards Solicitor at his Trial. The request necessary to produce perception eswas in itself so reasonable, that the capes the anatomist as well as the Government would scarcely have re- melapbysician.” fused it; but the death of the Bishop,

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screws.

shells, shell within shell, as we see in Count Giordano Riccati, in his the coats of an onion).".

work on strings and elastic fibres, has Of the l'elocity of Sound. proved, that sound passes through a "Corrected by the experiments of space filled with air, of a given length, various observers, the velocity of any in the same time that a column of impression transınitted by the com- . air of the same length, contained in moa air may, upon an average, be an organ-pipe open at both ends, "reckoned 11,300 feet in a second.” makes one vibration.

“ M. Biott, whose attention is ever An open organ-pipe of 10 feet alert, has seized an occasion of con makes 100 vibrations in a second. siderable improvements now going Air inadequate to the Phenomena forward in the capital of France, to

of Sounds. repeat, with great precision, experi “ It seems a question,” says Mr. ments similar to those proposed by Jones, “ more arduous than is comthe ingenious Chiadni, to determine inonly supposed, by what means sound the swiftness of sound through a solid is propagated. Natural Philosophy body."

has commonly taught that air is the “ 'The pipes intended to convey vehicle of sound; but, if sound goes water to Paris consist of cylinders of where no air can convey it, through cast iron, each eight feet-three inches the most solid bodies, and that with in length; the joints are secured by the greatest ease, some other cause a collar of lead, nearly half an inch besides the air must concur. The 'thick, covered with pitched cotton slightest scratching at one end of the ray, and strongly compressed by largest piece of timber is heard very

Into one end of the com- distinctly when the ear is applied to pound pipe was introduced an iron the other end, though it cannot be hoop, holding a bell with a clapper; beard at half the distance when we and at the other end, the observer use the air as the vehicle. This must was stationed. On striking the clap- be owing to the intervention of some per at once against the bell and the cause more moveable and more powinside of the tube, two distinct sounds erful than the air itself. If it be supwere heard at the remote extremity, posed that the particles of wood, the one sent through the iron, and which are in contact with the pin's the other conducted along the air. point, give motion to those that lie The juter val between these two next them, and so on, till the vibrasounds was measured by a chrono- tion reaches to the other extremity; meier that marked half-seconds. In the cause is not adequate. It is one experiment, the assemblage of therefore much easier to conceive pipes, including the leadeu joinis, ex that the effect arises from the vibrateuded to 2550 feet, or ucarly half a tious of a medium within the pores, . inile: and on a medium of 200 trials easily agitated, and communicating the two sounds were heard at the in- its pulses to any distance, rather than terval of 2.79 seconds. The time the from the action of the solid parts sound would take, according to the upon one another. Then will this calculation, to tra vel the same dis- occult communication of sound be tance through the aira is 2:5 seconds : similar, in some degree, to the paswhence the difference 29'' marks the sage of the electric ether; which goes time of conveyance along combined with difficulty through the air, but tubes. From numerous combined fies instantly through the pores of Triais, M. Biott concludes, that the solid bodies *.” true quantity was •26"; and therefore Through fir-wood sound passes that sound is transmitted ten oriwelve 17,400 feet, or more than three miles, times faster through cast iron than in a second. Mr. Chladni tells us that through the atmosphere."

the kinds of wood he examined would Wunck, on the velocity of sound in conduct sound about 11,000 to nearly wood, informs us, “that a sound was 18,000, and burnt pipe and clay from conveyed instantaneously through 36 10,000 to 12,000 feet in a second. connected laths of 24 feet each, or

* La Marck, on the medium of sound, 864 feet, if not through 72, which thinks it a medium more subtle than was the whole number employed : 72 air. I have had no opportunity of conlaths of 24 feet would equai 1728 sulting his observations, Jour. Phy, feet.”

XLIX. 397.

Derliam

any sound

Derham argues, that as sound which will give velocity of 49,000 moves near 1200 feet in a second, and feet in a second. the most violent wind not more than “ The sound of a bell,” says Der60 miles in an hour, which is at the ham, “ under water, is much duller rate of 88 feet in a second; the par and not so loud ; and it is also a 4th ticles of air which communicate the deeper.” sound must be more subtle than those Of the Divergence of Sound. which constitute wind. If wind acts “It has generally been asserted,” by the grosser parts of air, and sound says Dr. Young, chiefly on the auby the finer, this may be a reason why thority of Newton, that if they do not interfere, por disturb one be admitted through an aperture into another's motions.

a chamber, it will diverge from that The velocity of sound to a brisk aperture, equally, in all directions. wind is as fifty to one.

This, however, appears not to be the Sound describes equal spaces in fact, It is well known, that if a equal times. Derham has proved, by person calls to another with a speakexperiment, that all sounds whatever ing trumpet, he points it towards the travel at the same rate. The sound place where the bearer staods. i am of a gun, and the stroke of a hammer, assured by a very respectable nember are equally swift in their inotions. of the Royal Socieiy, and indeed it The softest whisper flies as swiftly, as was long ago observed by Grimaldi, far as it goes, as ihe loudest thuoder. that the report of a candon appears

Of Hearing under Water. many times louder to a person toI shall enliven this article with a wards whom it is fired, than to one merry story from Lord Bacon. “ Let placed in a contrary direction, It a man go into a bath, with a tub over inust have occurred to every one's his head ; let him speak, and any observation, that a sound, such as that shall stand without shall near his that of a mill, or fall oi water, has voice plainly, but yet extremely sharp appeared much louder after turning and exile (thin), like the voice of a corner, when the house or other puppets; but yet the articulate sounds obstacle no longer intervened.” of the words would not be confound

Of Loudness of sound. ed. A mao might think that the This depends on the force with Sicilian poet had knowledge of this which the particles of air strike the experiment: for he saith, that Her Why this loudness does not in. cules' page, Hylas, went with a water crease in arithmetical proportion we pot to fill at a pleasant fountain that know not. But of this we are cerwas near, and that the nymphs fell in tain: that four equal voices, or four love with the boy; and that Hercules, violins of equal power, are not four nuissiog his page, called him by his times as loud, as one voice, or one name aloud ibat all the shore rang of violin. Had the fact been otherwise, it; and that Hylas, from within, an the performances at Westminster swered his masier but with so snall Abbey, at Mr. Handel's commemoraand exile a voice, as Hercules thought tion, in one of which more than 600 he had beeo three miles off, when the were employed, would have stunned fountain, indeed, was fast by."

the audience. Sound is propagated through water The following passaye relative to with the velocity of 4900 feet in a the accuracy of the organ of hearing, second. N. B. An English mile is in distinguishing the difference of 5280 feet,

sounds nearly equal in force, is exTwo stones being struck together tremely curious and interesting. under water, may be heard at a much “ Tne waqt of a sure method of greater distance by an ear under measuring the monientum of the air water in the river, than it can be when agitated by a vibrating body, heard ihrough the air; Dr. Franklin with the same certainty with which thinks he has heard it a mile.

the ingles between rays of light are Professor Robison informs us that measured, appears to be the reason he heard the sound of a bell, traus wliy the accuracy in question is so mitted by water, at the distance of generally overlooked. But, though 1200 feet. Mr. Canton has ascertained it seems very difficult to give a genethat the elasticity of water is about ral rule for measuring mag aitudes of 22,000 times as great as that of air ; this description, the following expe

ear.

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