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Account of two Books.
THe Illustrious Author of this Book hath therein afresh furnisht the Philosophical World, with a set of very material and pregnant Experiments (to the number of 50) which are partly improvements of the former of this Nature, partly, (and those far more numerous) superadded new ones: concerning which, He declareth, that in great part he aimed thereby to shew, that these very Phænomena, which the School-Philosophers urge, as clear proofs of Nature's Abhorrency of a Vacuum, may be not only explicated, but actually exhibited, some by the Gravity, and some also by the bare spring of the Air; which latter he now mentions as a distinct thing from the other, not as if it were actually separated in these Tryals (since the Weight of the upper parts of the Air does, as 'twere, bend the Springs of the lower) but because that having in the formerly publisht experiments, and even in some of these, manifested the efficacy of the Air's Gravitation on Bodies, he thought fit to make it his task in many of these, to shew, that most of the same things, that are done by the Pressure of all the super-incumbent Atmosphere acting as a Weight, may be likewise perform'd by the Pressure of a small portion of Air, included indeed, but (without any new Compression) acting as a Spring.
The Experiments themselves, contain'd in this Book, are still of that sort, which need but a short absence of the Air; there being another sort, which require, that the Air should be kept out for a considerable time from the Bodies, whereon the trial is made; concerning which latter, the Author still gives the Reader hopes of presenting him in due time with such as may not be unacceptable to him. The Experiments of this Part are;
1. About the raising of Mercury to a great height in an open Tube, by the Spring of a little included Air; wherein 'tis discours'd, how this Experiment may be made use of against those, who in the explication of the Torricell. Experiment recurr to a Funiculus, or a Fuga Vacui.
