Moreover, it seemed to me convenient to informe your Highnesse of all the sequell, concerning the Controversie of which I treat, as it hath been advertised often already by others: and because the Doctrine which I follow, in the discussion of the point in hand, is different from that of _Aristotle_; and interferes with his Principles, I have considered that against the Authority of that most famous Man, which amongst many makes all suspected that comes not from the Schooles of the Peripateticks, its farr better to give ones Reasons by the Pen than by word of mouth, and therfore I resolved to write the present discourse: in which yet I hope to demonstrate that it was not out of capritiousnesse, or for that I had not read or understood _Aristotle_, that I sometimes swerve from his opinion, but because severall Reasons perswade me to it, and the same _Aristotle_ hath tought me to fix my judgment on that which is grounded upon Reason, and not on the bare Authority of the Master[2]; and it is most certaine according to the sentence of _Alcinoos_, that philosophating should be free. Nor is the resolution of our Question in my judgment without some benefit to the Universall[3], forasmuch as treating whether the figure of Solids operates, or not, in their going, or not going to the bottome in Water, in occurrences of building Bridges or other Fabricks on the Water, which happen commonly in affairs of grand import, it may be of great availe to know the truth. [2] _Aristotle_ prefers Reason to the Authority ofan Author. [3] The benefit of this Argument. I say therfore, that being the last Summer in company with certain Learned men, it was said in the argumentation; That Condensation was the propriety of Cold[4], and there was alledged for instance, the example of Ice: now I at that time said, that, in my judgment, the Ice should be rather Water rarified than condensed[5], and my reason was, because Condensation begets diminution of Mass, and augmentation of gravity, and Rarifaction causeth greater Lightness, and augmentarion of Masse: and Water in freezing, encreaseth in Masse, and the Ice made thereby is lighter than the Water on which it swimmeth. [4] Condensation the Propriety of Cold, according to the Peripateticks. [5] Ice rather water rarified, than condensed, and why: _What I say, is manifest, because, the medium subtracting from the whole Gravity of Sollids the weight of such another Masse of the said Medium; as_ Archimedes _proves in his_ [C] First Booke De Insidentibus Humido; _when ever the Masse of the said Solid encreaseth by Distraction, the more shall the_ Medium _detract from its entire Gravity; and lesse, when by Compression it shall be condensed and reduced to a lesse Masse._ [C] In lib: 1. of Natation of Bodies Prop. 7. [Sidenote: Figure operates not in the Natation of Sollids.]