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.
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.
COROLARY I.