[Sidenote: A Piramide or Cone, demitted with the Point downwards
shal swim, with its Base downward shall sink.]
_A Piramide or Cone put into the Water, with the Point downward
shall swimme, and the same put with the Base downwards shall
sinke, and it shall be impossible to make it float._
Now the quite contrary would happen, if the difficulty of Penetrating
the water, were that which had hindred the descent, for that the said
Cone is far apter to pierce and penetrate with its sharp Point, than
with its broad and spacious Base.
And, to demonstrate this, let the Cone be _A B C_, twice as grave as
the water, and let its height be tripple to the height of the Rampart
_D A E C_: I say, first, that being put lightly into the water with
the Point downwards, it shall not descend to the bottom: for the
Aeriall Cylinder contained betwixt the Ramparts _D A C E_, is equall
in Mass to the Cone _A B C_; so that the whole Mass of the Solid
compounded of the Air _D A C E_, and of the Cone _A B C_, shall be
double to the Cone _A C B_: And, because the Cone _A B C_ is supposed
to be of Matter double in Gravity to the water, therefore as much
water as the whole Masse _D A B C E_, placed beneath the Levell of the
water, weighs as much as the Cone _A B C_: and, therefore, there shall
be an _Equilibrium_, and the Cone _A B C_ shall descend no lower. Now,
I say farther, that the same Cone placed with the Base downwards,
shall sink to the bottom, without any possibility of returning again,
by any means to swimme.
[Illustration]
Let, therefore, the Cone be _A B D_, double in Gravity to the water,
and let its height be tripple the height of the Rampart of water L B:
It is already manifest, that it shall not stay wholly out of the
water, because the Cylinder being comprehended betwixt the Ramparts _L
B D P_, equall to the Cone _A B D_, and the Matter of the Cone, beig
double in Gravity to the water, it is evident that the weight of the
said Cone shall be double to the weight of the Mass of water equall to
the Cylinder _L B D P_: Therefore it shall not rest in this state, but
shall descend.
[Illustration]