To that which for a finall conclusion, _Signor Buonamico_ produceth of going about to reduce the descending or not descending, to the easie and uneasie Division of the _Medium_, and to the predominancy of the Elements: I answer, as to the first part, that that cannot in any manner be admitted as a Cause, being that in none of the Fluid _Mediums_, as the Air, the Water, and other Liquids, there is any Resistance against Division[32], but all by every the least Force, are divided and penetrated, as I will anon demonstrate: so, that of such Resistance of Division there can be no Act, since it self is not in being. As to the other part, I say, that the predominancy of the Elements in Moveables[33], is to be considered, as far as to the excesse or defect of Gravity, in relation to the _Medium_: for in that Action, the Elements operate not, but only, so far as they are grave or light: therefore, to say that the Wood of the Firre sinks not, because Air predominateth in it, is no more than to say, because it is less grave than the Water. Yea, even the immediate Cause, is its being less grave than the Water[34]: and it being under the predominancy of the Air, is the Cause of its less Gravity: Therefore, he that alledgeth the predominancy of the Element for a Cause, brings the Cause of the Cause, and not the neerest and immediate Cause. Now, who knows not that the true Cause is the immediate, and not the mediate[35]? Moreover, he that alledgeth Gravity, brings a Cause most perspicuous to Sence[36]: The cause we may very easily assertain our selves; whether Ebony, for example, and Firre, be more or less grave than water: but whether Earth or Air predominates in them, who shall make that manifest? Certainly, no Experiment can better do it than to observe whether they swim or sink. So, that he who knows, not whether such a Solid swims, unless when he knows that Air predominates in it, knows not whether it swim, unless he sees it swim, for then he knows that it swims, when he knows that it is Air that predominates, but knows not that Air hath the predominance, unless he sees it swim: therefore, he knows not if it swims, till such time as he hath seen it swim. [32] Water & other fluids void of Resistance against Division. [33] _T_he predominancy of Elements in Moveables to be considered only in relation to their excess or defect of Gravity in reference to the _Medium_. [34] _T_he immediate Cause of Natation is that the Moveable is less grave than the Water. [35] _T_he Peripateticks alledge for the reason of Natation the Cause of the Cause. [36] Gravity a Cause most perspicuous to sence.