(696)
same Author; A B (the semi-diameter of the Earth) is of 25870000 foot, and BC (the height of the Tower of the Asinelli in Bononia) of 240 foot; and therefore AC is 25870240, which hath the same proportion to FS, 15 foot, to wit, ye fall in one second, which AC in parts 20000000000 hath to FS 11596 54356224189; but supposing, with Riccioli, CSIA a semi-circle, FS is 53 parts, of which AC is 10000000000: Hence concludeth Angeli, that CSIA is no wayes near to a semi-circle; which is most sure, if so be the weight fall not to the Center of the Earth precisely in 6 hours: For, in this case of Riccioli, the weight falls to the Center of the Earth in 21 minutes and 53 seconds.
Manfredi in his Answer for Riccioli affirms, that Angeli understands not the Rule of Three, in giving out FS, for 11596 54356224189, of which AC is 200000000000: And Angeli in his Reply affirms his Analogy to be so clear, that there can be nothing said more evident than it self to confirm it; referring in the mean time the further determination to Geometers.
Angeli might have answer'd Riccioli's Argument, granting the weight to move equally in a semi-circle, by distinguishing his Minor thus;
Nulla Corpora gravia descenderent ad Terram cum velocitatis incremento reali ac notabili, si Velocitas computetur in circumferentia semi-circuli; Minor propositio est vera. At non computatur ita Motus descensivus: nam hic motus æqualis in circumferentia semi-circuli CIA. componitur ex motu æquali in quadranti CD, & motu accelerato in semidiametro est versus & simplex motus descensivus; in qua acceptione Minor propositio est falsiẞima, & Riccioli etiam experientis contraria. But it seems, that Angeli answereth otherwise, to make Riccoli sensible, that CIA is no semicircle; concerning the nature of which Line they debate very much throughout the whole discourse,
The Second Argument is much insisted upon by Angeli, to make his solution clear to vulgar capacities; but the substance of all is, That the Canon-ball hath not only that violent motion, impressed by the Fire, but also all these motions proper to the Earth, which were communicated to it by the impulse received from the Earth:
