PART III
PROPORTIONS OF MOTIONS
AND MAGNITUDES.
CHAPTER XV.
OF THE NATURE, PROPERTIES, AND DIVERS
CONSIDERATIONS OF MOTION AND
ENDEAVOUR.
[1.]. Repetition of some principles of the doctrine of motion formerly set down.—[2.] Other principles added to them.—[3.] Certain theorems concerning the nature of motion.—[4.] Divers considerations of motion.—[5.] The way by which the first endeavour of bodies moved tendeth.—[6.] In motion which is made by concourse, one of the movents ceasing, the endeavour is made by the way by which the rest tend.—[7.] All endeavour is propagated in infinitum.—[8.] How much greater the velocity or magnitude is of a movent, so much the greater is the efficacy thereof upon any other body in its way.
Repetition of some principles of the doctrine of motion formerly set down.
1. The next things in order to be treated of are MOTION and MAGNITUDE, which are the most common accidents of all bodies. This place therefore most properly belongs to the elements of geometry. But because this part of philosophy, having been improved by the best wits of all ages, has afforded greater plenty of matter than can well be thrust together within the narrow limits of this discourse, I thought fit to admonish the reader, that before he proceed further, he take into his hands the works of Euclid, Archimedes, Apollonius, and other as well ancient as modern writers. For to what end is it, to do over again that which is already done? The little therefore that I shall say concerning geometry in some of the following chapters, shall be such only as is new, and conducing to natural philosophy.
I have already delivered some of the principles of this doctrine in the eighth and ninth chapters; which I shall briefly put together here, that the reader in going on may have their light nearer at hand.
First, therefore, in chap. VIII. [art. 10], motion is defined to be the continual privation of one place, and acquisition of another.
Secondly, it is there shown, that whatsoever is moved is moved in time.