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* 1.1UPon the eduction of the lower extreme of the Tube out of the region of the Restagnant Quicksilver, into that of Water superaffused; wherefore doth the Water instantly intrude into the Tube, and the Quicksilver residuous therein by sensible degrees deflux, until it hath totally surrendred unto it?
This Phaenomenon can have for its Cause no other but the great Dis∣parity of weight betwixt those two Liquors. For,* 1.2 insomuch as the subsi∣stence of the Quicksilver in the erected Tube, at the altitude of 27 di∣gits, justly belongs to the Aequipondium betwixt it and the circum∣pendent Cylindre of Aer; and the proportion of Weight which Quick∣silver holds to Water, is the same that 14 holds to 1: it must as ma∣nifestly, as inevitably follow, that the Water, being by so much less able, in regard of its so much minority of Weight, to sustain the impulse of the Aer uncessantly contending to deliver it self from that immoderate Compression, must yeild to the descending Base of the aereal Cylindre, and so ascend by degrees, and possess the whole Space; every part of Quicksilver that delapseth, admitting 13 parts of Water into the Tube.
Here occurrs to us a fair opportunity of erecting,* 1.3 upon the praemised foundation, a rational Conjecture concerning the perpendicular Extent of the Region of Aer from the face of the Terraqueous Globe. For, if Aer be 10••0 times (according to the compute of the great Mersennus (reflect. physicomath. pag. 104) who exceedingly differs from the opinion of Galilaeo (Dialog. al. moviment. pag. 81.) and Marinus Ghetaldus (in Archimed. promot.) both which demonstrate Aer to be only 400 times) lighter then Water, and Water 14 times lighter then Quicksilver: hence we may con∣clude (1) That Aer is 14000 times lighter then Quicksilver; (2) That the Cylindre of Aer aequiponderant to the Cylindre of Quicksilver of the altitude of 27 digits, is 14000 times higher; and (3) That the altitude of the Cylindre of Aer amounts to 21 Leucae, or Leagues. Since 14000 times 27 digits (i. e. 378000 digits) divided by 180000 digits (so many amounting to a French League, that consisteth of 15000 feet) the Quo∣tient will be 21.
From the so much discrepant opinions of these so excellent Mathema∣titians, and most strict Votaries of Truth, Galilaeo and Mersennus;* 1.4 each of which conceived his way for the exploration of the exact proportions of Gravity betwixt Aer and Water, absolutely Apodictical: we cannot omit the opportunity of observing; how insuperable a difficulty it is, to conciliate Aristotle to Euclid, to accommodate those Axioms, wch concern Quantity abstract from Matter, to Matter united in one notion to Quantity, to erect a solid fabrick of Physiology on Foundations Mathematical. Which Difficulty the ingenious Magnenus well resenting, made this a chief praepa∣ratory Axiom to his second Disputation concerning the Verisimility of Democritus Hypothesis of Atoms: Non sunt expendendae Actiones Physicae regulis Geometricis; subnecting this ponderous Reason, Cum Demon∣strationes Geometricae procedant ab Hypothesi, quam probare non est Mathema∣tici, sed alterius Facultatis, quae eam refellit; id eo lineis Mathematicis, re∣gulisque strictè Geometricis, Actiones Physicae non sunt expendendae. (Demo∣crit. Reviviscent. p. 318.)
* 1.5And now at length having run over these six stages, in as direct a course, and with as much celerity, as the intricacy and roughness of the way would tolerate; hath our Pen attained to the end of our Digression: wherein, whether we have gratified our Reader with so much either of sa∣tisfaction, or Delight, as may compensate his time and patience; we may not praesume to determine. However, this praesumption we dare be guilty of, and own; that no Hypothesis hitherto communicated, can be a better Clue to extricate our reason from the mysterious Labyrinth of this Experiment, by solving all its stupendious Apparences, with more verisi∣mility, then this of a Disseminate Vacuity, to which we have adhaered. But, before we revert into the straight tract of our Physiological journey, the praecaution of a small scruple deduceable from that we have consigned a Cylindrical Figure to the portion of Aer impendent on the surface of the Restagnant Liquors; adviseth us to make a short stand, while we advertise; That though we confess the Diametre of the Sphere of Aer to be very much larger then that of the Terraqueous Globe, and so, that the Aer, from the Convex to the Concave thereof incumbent on the surface of the Restagnant Liquors in the vessel placed on the Convex of the Earth, doth make out the Section or Frustum of a Cone, whose Basis is in the summity of the Atmosphere; and point at the Centre of the Earth (as this Diagram exhibiteth.)
Note that neither Earth, Aer, Vessel, nor Tube, are delineated according to their due proportions: since so, the Earth would have appeared too great, and the rest too small, for requisite inspection.
Yet, insomuch as the Aer is Aequiponderant to the Cylindre of Quick∣silver contained in the Tube (the only requisite to our praesent purpose) no less in the Figure of a Cone, then in that of a Cylindre; and since both Mersennus and Gassendus (to either of which we are not worthy to have been a meer Amanuensis) have waved that nicety, and declared themselves our Praecedents, in this particular: we have thought our selves excusable for being constant to the most usual Apprehension, when the main interest of Truth was therein unconcerned.
Art. 1. The sixth and last considera∣ble Difficulty.
Art. 2. The clear solu∣tion thereof, by the great disproportion of weight be∣twixt Quicksil∣ver and VVater.
Art. 3. A Corollary; the Altitude of the Atmosphere conjectured.
Art. 4. A second Co∣rollary; the desperate•• Dif∣ficulty of con∣ciliating Phy∣siology to the Mathematicks: instanced in the much dis∣crepant opini∣ons of Galilaeo and Mersennus, concerning the proporti∣o•• of Gravity that Aer and VVater hold each to other.
Art. 5. The Conclusion of this Digres∣sion: and the reasons, why the Author ad∣scribes a Cylin∣drical Figure to the portion of Aer impen∣dent on the Restagnant Liquors, in the Experiment.