228 Of Winds and Sounds.

the Point of Percussion, as a Centra ^concentric hollow Superficies or Shells of -d'f.which are not improperly called A^ rtPulses or Waves of Air: Analagous ^■which are the circular Waves genera^on the Surface of Water all aroundPoint where any Impression is made, i sl a 'Manner or Direction whatsoever (CHI)*

by Sir Isaac Newton a Wave or Pulse os Air. In fffi,Wave the Particles from A to N are in a dilated dand from N to X in a contracted or condensed 6which two Parts of the Wave answer to the cor> cand convex, or low and high Part of a watry ^

9. As the Chord goes on to make another Vi

it will not only continue to agitate the Air at W $in Motion, but will spread the Pulsation of the Jmuch. farther, and by the same Degrees as before , 0 fthe like will happen after every compleat Vibr^ 1 ^the String. Thus the Air being a fluid Body,Impression made on any one Part affecting all b etides alike around it, ’tis plain, those Pulses ^propagated in every Direction all around in coU 0Aerial Shells or spherical Waves of Air. . jyfe'

10. That the Motion of the Pulses in an elalh cdium is analagous to that of Waves generated in ^ jjjetface of stagnant Water, is evident, when we c ? n -^Jis'that the Condensation of the Parts of the elaft lC ' t j,edium is in Lieu of the Elevation-of the

clastic Force effects the fame in the Medium as pfi cSdoes in the Water, and the densest Parts of ,es e 'correspond to the highest Parts of the Waves. , ^fore as there is so great an Affinity between ^Phænomena, it will be requisite, before weto explain the Nature and Properties of aqueous ,

which will therefore be shewn in the next Jnnofi {£ o>Plate (CIII) 1. Sir Ijaac Nezvton explains the N a ^ fipXXXII. Waves in Water after the following Manner. aw

Fig-6,7.