Let us not then despise those Hints, though very dark, which Reason, after some contemplation, offereth to our Intelligence, and lets be content to be taught by Archimedes, Lib. 1. of Natation Prop. 7that then any Body shall submerge in water, when it shall be specifically more grave than it, Id. Lib. 1 Prop. 8and that if it shall be less grave, it shall of necessity swim, and that it will rest indifferently in any place under water, if its Gravity be perfectly like to that of the water.
Id. Lib. 1 Prop. 3These things explained and proved, I come to consider that which ofters itself, touching whatthe Diversity of figure given unto the said Moveable hath to do with thede Motions and Rests; and proceed to affirme, that,
THEOREME III.
So that if a Solid being formed, for example, into a Sphericall Figure, doth sink or swim in the water, I say, that being formed into any other Figure, the same figure in the same water, shall sink or swim: nor can such its Motion by the Expansion or by other mutation of Figure, be Impeded or taken away.
The Expansion of Figure, retards the Velocity of the ascent or descent of the Moveable in the water; but doth not deprive it of all Motion.The Expansion of the Figure may indeed retard its Velocity as well of ascent as descent, and more and mere according as the said Figure is reduced to a greater breadth and thinness: but that it may be reduced to such a form as that that same matter be wholly hindred from moving in the same water, that I hold to be impossible. In this I have met with great contradictors, who producing some Experiments and in perticular a thin Board of Ebony, and a Ball of the same Wood, and shewing how the Ball in Water descended to the bottom, and the Board being put lightly upon the Water submerged not, but rested; have held, and with the Authority of Aristotle, confirmed themselves in their Opinions, that the Cause of that Rest was the breadth of the Figure, unable by its small weight to pierce and penetrate the Resistance of the Waters Crassitude, which Resistance is readily overcome by the other Sphericall Figure.
This is the Principal point in the present Objection, in which I perswade my self to be on the right side.
Therefore, beginning to investigate with the examination of exquisite Experiments that really the Figure doth not a jot alter the descent or Ascent of the same Solids, and having already demonstrated that the greater or less Gravity of the Solid in relation to the Gravity of the Medium is the cause of Descent or Ascent: when ever we