Of Winds and Sounds.

Agrees of what we call the Note, Tone,° r Tune of Sounds, in regard of which

they

segmentation does principally consist. For all reci-°cal Motion, in every Return, is augmented by its(• ner ating Cause, which is here the tremulous Mo-b° n of the Parts of the Tube. Therefore in every^Percussion from the Sides of the Tube, the Agi-fc '?i>s and Pulses of the confined Air must necessarily^ ln creased ; and consequently this Augmentation of^ Impetus of the Pulses must be proportional to the^mber of such Repercussions, and therefore to theH^gth of the Tube, and to such a Figure as is mostf jussive of them. Whence it appears, that the Pa-Trumpet is of all others the mojl unfit for this Pur-■A instead of being the best.

t 0 ®‘ But there is one Thing more which contributesf Augmentation of those Agitations of Air in theand that is the Proportion which the severalt t ° ft *ons of Air bear to each other when divided byInverse Sections, at very small but equal Distances,tb One End of the Tube to the other. Thus letrf 0 e several Divisions be made at the Points s, b, e,&c. in which let the Right Lines ah, bl, cm,W. &c. be taken in Geometrical Proportion. Thens, fte Portions of Air contained between B and a,b and c, c and d, &c. be very nearly in the% e Proportion, as being in the same Ratio with theirO, ^hen the Points of Division are indefinitely near* et her.

But it has been shewn already, that when anyentity of Motion is communicated to a Series ofV' C Bodies, it will receive the greatest Augmenta-"'hen those Bodies are in Geometrical Proportion,lip^fore since the Force of the Voice is impress’dan( i gradually propagated through a Series ofPortions of Air in a Geometrical Ratio to eachit shall receive the greatest Augmentation pol-io. Now

249

Plate

xxxnr.Fig. 6.