Hence in a Church, the nearer the Preacher stands to the Wall (and certainly 'tis much the best way to place Pulpits near the Wall) the better is he heard, especially by those who stand near the Wall also, though at a greater distance from the Pulpit; those at the remotest end of the Church, by laying their Ears somewhat close to the Wall, may hear him easier than those in the middle.
Hence also do arise Whispering Places. For the Voice being apply'd to one end of an Arch, easily rowls to the other. And indeed were the Motion and Propagation of Sounds but rightly understood, 'twould be no hard matter to contrive Whispering Places of infinite variety and use. And perhaps there could be no better or more pleasant hearing a Consort of Musick than at such a place as this, where the Sounds rowling along together, before they come to the Ear, must needs consolidate and imbody into one; which becomes a true composition of Sounds, and is the very Life and Soul of Consort.
2. If the Sonorous Body be plac'd near Water, the Sound will easily be convey'd, yet mollified; as Experience teacheth us from a Ring of Bells near a River, and a great Gun shot off at Sea, which yet differ much in the strength, and softness and continuance, or propagation of their Sounds, from the same at Land, where the Sound is more harsh and more perishing, or much sooner decays.
3. In a Plain a Voice may be heard at a far greater distance than in uneven Ground.
The Reason of all which last nam'd Phænomena is the same; because the Sonorous Air meeting with little or no resistance upon a Plane (much less upon an Arch'd) smooth Superficies, easily rowls along it, without being let or hinder'd in its Motion, and consequently without having its parts disfigured, and put into another kind of Revolution, than what they had at the first begetting of the Sound. Which is the true cause of its Preservation or Progression, and fails much when the Air passes over an uneven Surface, according to the degrees of its inequality, and somewhat also, when it passes over the plain Superficies of a Body that is hard and resisting.
Wherefore the smooth Top of the Water (by reason of its yielding to the Arch'd Air, and gently arising again with a kind of Resurge, like to Elasticity, tho' it be not so, by which Resurge it quickens and hastens the motion of the Air rowling over it, and by its yielding preserves it in its Arch'd Cycloidical or Elliptical Figure) the smooth Top of the Water, I say, for these Reasons, and by these Means, conveys a Sound more entire, and to a greater distance than the plain Surface of a piece of Ground, a Wall, or any other Solid Body whatever, can do.
As for the Speaking Trumpet, by which a Voice may be convey'd to a considerable distance, I refer its consideration to that of Refracted Sounds, or Refracted Audition.
Thus much of the Improvements of Hearing, that respect its Object, which is Sound.
2. The Organ and Medium are to be consider'd. And, 1. The Organ, which is the Ear, is helpt much by placing it near a Wall (especially at one end of an Arch, the Sound being begotten at the other) or near the Surface of Water, or of the Earth, along which the Sounds are most easily and naturally convey'd, as was before declar'd. And 'tis incredible how far a Sound made upon the Earth (by the trampling of a Troop of Horses, for Example) may be heard in a still Night, if a Man lays his Ear close to the Ground in a large Plain.
Otacousticks here come in for helping the Ear; which may be so contriv'd (by a right understanding the Progression of Sounds, which is the principal thing to be known for the due regulating all such kinds of Instruments) as that the Sound might enter the Ear without any Refraction, but as now they are generally made I refer them to Refracted Audition.