23 *

Of Winds and Sounds.

^ay be heard by several Persons , in any dif-^rent Situations with respect to the sound-mg Body, if not at too great a Distance.

II. Phe Denfity of these aerial Pulses de-ereases, as the Squares of the Distances fromthe sounding Body increase: Eor since the^orce or Motion in each Shell is the fame,lt must decrease as the Number of Particles^creases in each Shell : But this Number°f Particles is as the Superficies of the^hell, which is as the Squares of the Dia-meter or Semidiaiueter of the Sphere, thatls > as the Distance from the sounding Bo-dy. Hence the Distinction of Sounds in-to loud and low, strong and weak, according*s we are nearer to, or farther from, the

sounding

7 - Whence because ABC in very large and wideleaves is nearly equal to the Brfeadth A C ; therefore'''hen the Waves are 39,2 Inches broad, they will un-gulate in one Second of Time ; and consequently sinceshe Times of all the Undulations are equal, there will° e 39,2X60=2352 Inches, or 196 Feet run thro’byj_Wave in one Minute, which is 11760 Fee.t^rr Hour.thnce also the Velocity of greater or lesser Waves will. increased or diminished in the subduplicate Propor-tl °n of their Breadth ; that is, if V = Velocity oftile greater Waves ABCD, and v = Velocity of thehffer Waves a, b, c, d, e, f, &c. then it will be V ;

\/AC : \/ a ,c. Because the Velocities and* "ties of Bodies moved in any Manner by Gravity, areP r °portional to the square Roots of the perpendicular'latitudes ; and those Altitudes are as the Lengths ofe ndulums, and therefore as the Breadth of Wav,es P

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