unworthily contradicted by such as should oppose it, saying: Thou mis-alledgest as Cause of the motion of the Bark towards the South, the _Impetus_ of the Stream of the Water above that of the South Winde; mis-alledgest I say, for it is the Force of the North Winde opposite to the South, that is able to drive the Bark towards the South. Such an Objection would be superfluous, because he which alledgeth for Cause of the Motion the Stream of the Water, denies not but that the Winde opposite to the South may do the same, but only affirmeth that the force of the Water prevailing over the South Wind, the Bark shall move towards the South: and saith no more than is true. And just thus when _Archimedes_ saith, that the Gravity of the Water prevailing over that by which the moveable descends to the Bottom, such moveable shall be raised from the Bottom to the Surface alledgeth a very true Cause of such an Accident, nor doth he affirm or deny that there is, or is not, a vertue contrary to Gravity, called by some Levity, that hath also a power of moving some Matters upwards. Let therefore the Weapons of _Signor Buonamico_ be directed against _Plato_[25], and other _Ancients_, who totally denying _Levity_, and taking all Bodies to be grave, say that the Motion upwards is made, not from an intrinsecal Principle of the Moveable, but only by the Impulse of the _Medium_; and let _Archimedes_ and his Doctrine escape him, since he hath given him no Cause of quarelling with him. But if this Apologie, produced in defence of _Archimedes_, should seem to some insufficient to free him from the Objections and Arguments, produced by _Aristotle_ against _Plato_, and the other _Ancients_, as if they did also fight against _Archimedes_, alledging the Impulse of the Water as the Cause of the swimming of some Bodies less grave than it[26], I would not question, but that I should be able to maintaine the Doctrine of _Plato_ and those others to be most true, who absolutely deny Levity, and affirm no other Intrinsecal Principle of Motion to be in Elementary Bodies save only that towards the Centre of the Earth[27], nor no other Cause of moving upwards, speaking of that which hath the resemblance of natural Motion, but only the repulse of the _Medium_, fluid, and exceeding the Gravity of the Moveable[28]: and as to the Reasons of _Aristotle_ on the contrary, I believe that I could be able fully to answer them, and I would assay to do it, if it were absolutely necessary to the present Matter, or were it not too long a Digression for this short Treatise. I will only say, that if there were in some of our Ellementary Bodies an Intrinsecall Principle and Naturall Inclination to shun the Centre of the Earth, and to move towards the Concave of the Moon, such Bodies, without doubt, would more swiftly ascend through those _Mediums_ that least oppose the Velocity of the Moveable, and these are the more tenuous and subtle; as is, for example, the Air in comparison of the Water, we daily