Physiologia Epicuro-Gassendo-Charltoniana, or, A fabrick of science natural, upon the hypothesis of atoms founded by Epicurus repaired [by] Petrus Gassendus ; augmented [by] Walter Charleton ...

SOLUT.

To solve this (by many accounted inexplicable) Aenigme, we need only to have recurse to our long since antecedent Distinction of a Vacuity Disseminate, and Coacervate: for, that once entered our judgment, we cannot indubitate that ingenious Experiment of Gaspar Berthius, laureat Ma∣thematician at Rome (frequently, and alwayes with honourable Attributes, mentioned by Father Kircher, in sundry of his Physicomathematical discour∣ses) which sensibly demonstrateth the actual production of a Sound, in a Disseminate Vacuity.

The Experiment is thus made. Having praepared a large Concave and almost sphaerical Glass, aemulating the figure of a Cucurbite or Cupping-glass; fix a small Bell, such as is usual in striking Watches of

the largest size, on one side of the concave thereof, and a moveable Ham∣mer, or striker, at fit distance, on the other, so as the Hammer being ele∣vated may fall upon the skirts of the Bell: and then lute or coement on the Glass, firmly and closely (that all sensible insinuation of the ambient aer be praevented) to one extreme of a Glass Tube, of about an inch diame∣tre in bore, and 8 or 10 feet in length. Then, reversing the Tube, pour into it a sufficient quantity of Quicksilver, or Water, to fill both it and the Head exactly. This done, stop the other extreme of the Tube with your finger, or other stopple accommodate to the orifice; and after gentle inversion, immerge the same to a foot depth in a Vessel of Water, and withdraw your stopple, that so much of the Quick∣silver contained in the Head and Tube, as is superior in Gravity to the Cylindre of Aer, from the summity of the Atmosphere incumbent on the surface of the Water in the subjacent Vessel may fall down, leaving a considerable void Space in the superior part of the Tube. Lastly, apply a vigorous Loadstone to the outside of the Glass Head, in the part respecting the moveable extreme of the Hammer; that so, by its Magnetical Effluxions transmitted through the incontiguities or mi∣nute pores of the Glass, and fastned on to its Ansulae or smal Holds, it may elevate the same: which upon the subduction of its Attrahent, or Elevator, will instantly relapse upon the Bell, and by that percussion produce a clear and shrill sound, not much weaker than that emitted from the same Bell and Hammer, in open aer.

Now, that there is a certain Vacuity in that space of the Head and Tube deserted by the delapsed Quicksilver, is sufficiently conspicuous even from hence; that the ambient Aer seems so excluded on all hands, that it cannot by its Periosis (to borrow Platoes word) or Circumpulsion, succeed into the room abandoned by the Quicksilver, and so redintegrate the soluti∣on of Continuity, as in all other motions.

And that this Vacuity is not Total, or Coacervate, but only Gradual or Desseminate, may be warrantably inferred from hence; (1) That Nature is uncapable of so great a wound, as a Coacer∣vate Vacuity of such large dimensions, as we have argued in our Chapter of a Vacuum Praeternatural, in the First Book: (2) That a Sound is produced therein, for since a Sound is an Affection of the Aer, or rather, the Aer is the Material Cause of a Sound, were there no aer in the Desert space, there could be no Sound. Where∣fore, it is most probable, that in this so great distress ingenious Nature doth relieve herself by the insensible transmission of the most aethereal or subtile particles of the Circumpulsed Aer, through the small and even with a microscope invisible Pores of the Glass, into the Desert Space; which replenish it to such a degree, as to praevent a Total though not a Dispersed Vacuity therein: and though the Grosser Parts of the extremly comprest Aer cannot likewise permeate the same slender or narrow Inlets; yet is that no impediment to the Creation of a Sound therein, because the most tenuious and aethe∣real part of the aer, is not only a sufficient, but the sole material of a Sound, as we have more than intimated in the 15. Art. 2. Sect. of the present Chapter.

The only Difficulty remaining, therefore, is only this; Why the sound made in the disseminate Vacuity should through the Glass-head pass so easily and imperturbed, as to be heard by any in the circumstant space; when com∣mon Experience certifieth, that the Report of a Cannon, at the distance of only a few yards, cannot be heard through a Glass window into a room void of all chinks or crannies?

Nor need any man despair of expeding it. For, whoso considers the extraordinary and inscrutable wayes to which Nature frequently recurrs, in cases of extreme Necessity; and that the Distress she undergoes in the introduction of this violent Vacuity (where her usual remedy the Peristal∣tick motion, or Circumpulsion of the Aer, is praevented by the interpo∣sition of a Solid) is much more urgent than that she is put to in the Com∣pression of the ambient aer by the explosion of Canons (where the am∣plitude of uninterrupted space affords freedome of range to the motion imprest) we say, whoso well considers these things, cannot doubt, but that it is much easier to Nature to admit the trajection of the Sound pro∣duced in the Disseminate Vacuity, through the pores of the Glass-head, than the transmission of an External Sound into a close Chamber, through a Glass window, where is no Concavity for the Corroboration or Multi∣plication of the Sound, and consequently where the impulse is far less (respective to the quantity of the aer percussed) and the resistence as much greater.