For if he had undertook to dispute against resembling had ascribed that revolution to the Earth from its first creation, he would have confuted them by saying, that if the Earth had alwayes moved, there might never have been positioned upon it both males or stones; much much less might buildings have been erected, or Cities founded, &c. Sagr.I am fairly very much pleased with it, for that I keep in mind that once i studied Logick, I may never comprehend that a lot cry’d up and most potent demonstration of Aristotle. From the issues premised I collect that the project swiftly swinged spherical by the projicient, in its separating from it, doth retain an impetus of persevering with its motion by the appropriate line, which toucheth the circle described by the motion of the projicient in the point of separation, by which movement the project goeth continually receding from the centre of the circle described by the motion of the projicient. Salv.Therefore a moveable departing from the contact, and moving by the streight Tangent, goeth frequently farther and farther from the contact, and in addition from the centre of the circle. Now I proceed a little bit farther, and ask you, whether or not the moveable after its separation, in continuing the fitting movement goeth all the time equally receding from the centre, or if you’ll, from the circumference of that circle, of which the precedent movement was an element; which is as a lot as to say, Whether a moveable, that forsaking the point of a Tangent, and transferring along by the mentioned Tangent, doth equally recede from the purpose of contact, and from the circumference of the circle?
Salv.And that i, Simplicius, will drive it home, and re-inforce it, by shewing but extra sensibly, that it’s true that grave our bodies turn’d with velocity a couple of settled centre, do acquire an impetus of moving, and receding to a distance from that centre, even then when they’re in a state of getting a propension of moving naturally to the same. And lastly, we see boys throw stones a good way, by swinging spherical a bit of a stick, at the end of which the stone is let right into a slit (which stick is known as by them a sling;) all which are arguments of the truth of the conclusion, to wit, that the vertigo or swing conferreth upon the moveable, a motion towards the circumference, in case the movement be swift: and due to this fact if the Earth revolve about its own centre, the motion of the superficies, and particularly in the direction of the good circle, as being incomparably more swift than those earlier than named, should extrude all things up into the air.
Salv.Allow us to go on subsequently; and let Simplicius, inform me what that motion is which the stone maketh that is held quick in the slit of the sling, when the boy swings it about to throw it a great way? Salv.And when the stone leaveth the sling, what’s its motion? Salv.The motion of the stone while it was in the slit, you will have affirmed already to be circular; now circularity opposeth directness, there not being within the circular line any part that’s direct or streight. Salv.If then the line of the tasks movement be to proceed with out making an angle upon the circular line described by it, while it was with the projicient; and if from this circular motion it must move to the best movement, what ought this proper line to be? And that you may plainly see that you already know the factor I ask you, and onely want language to express it, tell me, if you shoot a bullet out of a gun, in direction of what part is it, that its acquired impetus carrieth it? Simpl.I imagine that it beginneth presently; for it not having any thing to uphold it, its proper gravity can’t but operate.
And since such overthrows and extrusions cannot be made upon buildings and males, which were not before on the Earth, nor can men be placed, nor buildings erected upon the Earth, unlesse when it standeth nonetheless; therefore subsequently it is cleer, that Ptolomy argueth in opposition to those, who having granted the stability of the Earth for a while, that’s, so long as living creatures, stones, and Masons had been in a position to abide there, and to construct Palaces and Cities, make it afterwards precipitately moveable to the overthrow and destructi- of Edifices, and living creatures, &c. Salv.We are able to assume no other, if we do but consider the way he taketh to confute their assertion;Aristotle and Ptolomy appear to confute the mobility of the Earth towards those that thought that it having a very long time stood nonetheless, did start to move in the time of Pythagoras the confutation of which consists within the demolition of buildings, and the tossing of stones, living creatures and men themselves up into the Air. Salv.Ptolomey both argueth in opposition to these who’ve esteemed the Earth at all times moveable; or towards such as have held that it stood for a while nonetheless, and hath since been set on transferring. But in that he arguing, saith that the Earth doth not move, as a result of that beasts, males, and houses before plac’d on the Earth would precipitate, he supposeth the Earth to have been once in such a state, as that it did admit men and beasts to remain, and build thereon; the which draweth on the consequence, that it did for a while stand nonetheless, to wit, was apt for the abode of animals and erection of buildings.