and none light: For that the same would befall the Fire and Air, if put in the Bottom of the water. And, howbeit, Aristotle grants a Pulsion in the Elements, by which the Earth is reduced into a Sphericall Figure, yet nevertheless, in his judgement, it is not such that it can remove grave Bodies from their naturall places, but rather, that it send them toward the Centre, to which (as he somewhat obscurely continues to say,) the water principally moves, if it in the interim meet not with something that resists it, and, by its Gravity, thrusts it out of its place: in which case, if it cannot directly, yet at least as well as it can, it tends to the Centre: but it happens, that light Bodies by such Impulsion, do all ascend upward: but this properly they have by nature, as also, that other of swimming. The causes of Natation & Submersion, according to the Peripateticks.He concludes, lastly, that he concurs with Archimedes in his Conclusions; but not in the Causes, which he would referre to the facile and difficult Separation of the Medium, and to the predominance of the Elements, so that when the Moveable superates the power of the Medium; as for example, Lead doth the Continuity of water, it shall move thorow it, else not.
This is all that I have been able to collect, as produced against Archimedes by Signor Buonamico: who hath not well observed the Principles and Suppositions of Archimedes; which yet must be false, if the Doctrine be false, which depends upon them; but is contented to alledge therein some Inconveniences, and some Repugnances to the Doctrine and Opinion of Aristotle. In answer to which Objections, I say, first, The Authors answer to the first Objection.That the being of Archimedes Doctrine, simply different from the Doctrine of Aristotle, ought not to move any to suspect it, there being no cause, why the Authority of this should be preferred to the Authority of the other: but, because, where the decrees of Nature are indifferently exposed to the intellectuall eyes of each, the Authority of the one and the other, loseth all anthenticalness of Perswasion, the absolute power residing in Reason; therefore I pass to that which he alledgeth in the second place, The Authors answer to the second Objection.as an absurd consequent of the Doctrine of Archimedes, namely, That water should be more grave than Earth. But I really find not, that ever Archimedes said such a thing, or that it can be rationally deduced from his Conclusions: and if that were manifest unto me, I verily believe, I should renounce his Doctrine, as most erroneous. Perhaps this Deduction of Buonamico, is founded upon that which he citeth of the Vessel, which swims as long as its voyd of water, but once full it sinks to the Bottom, and understanding it of a Vessel of Earth, he infers against Archimedes thus: Thou sayst that the Solids which swim, are less grave than water: this Vessell swimmeth: therefore, this Vessell is lesse grave than water. If this be the Illation. I easily answer, granting that this Vessell is lesse grave than water, and denying the other consequence,