Of Winds and Sounds;

.. J'rom the Nature of a Fluid, whateverPotion is generated in any one Particle, it

is

22 5

k

anner not quite so physical and mathematical as the

ature of the Thing required. I shall refer the Readero the Commentaries of Mess. Le Seur and Jacquier oil!j e Principia, where they will find Sir Isaac Newton’sI ypothesis relating to the Motion of the Particles of anMastic Medium to be fallacious ; and other MethodsPsopofed, by which the Newtonian Doctrine of SoundJ i re ft°rcd. I stiall here add an Explication of suchhœnomena only, as are of principal Concernment, and1 the fame time pretty easy to be understood.

. 2. Let ABC be an elastic String or Chord, fixed? the Points A and C, and drawn out of its natural’ght-lin’d Situation ABC. Such a Chord, in its StateJ Tension, will, when let go, return to its natural.Port, not only to its natural Situation ADC, butthe Motion it there has will go on to E, so that^ E is nearly equal to B D ; and from thence it willEsorn again nearly to B ; which Motion from B to-ar ds E, and from E towards B, will be reciprocatedgreat Number of Times before the Chord will come

to

n ® State of Rest: And each Motion through the SpaceE is called a Vibration of the Chord.

jj 3; When the Chord begins its Motion at first from’it strikes the Particle of Air contiguous to it in B," that will by its Approach towards the next affect^ hy means of the repulsive Power, which keeps% ertl at Esiual Distances from each other ; and so{ j.’ through such a Number of Particles as can receivea e Motion while the String moves from B to D. LetE, C, D, E, F, G, &c. represent such a Seriesp , ar ticles of Air at an equal Distance, and the firstj^tticle A contiguous to the middle Point B of such ar ' n g, Lnd agitated by it in its Motion.

The String beginning to move, all the Particles{(jj tw C, will begin to move forwards also ; and since^ Motion i s propagated in Time, let E be the re-*®st Particle moved while the Chord is moving fromVqi. n, B to

PlateXXXILFig. 4*