Page:The Mathematical Principles of Natural Philosophy - 1729 - Volume 1.djvu/64

20 at once, or gradually and ucceively. And this motion (being always directed the ame way with the generating force) if the body moved before, is added to or ubducted from the former motion, according as they directly conpire with or are directly contrary to each other; or obliquely joyned, when they are oblique, o as to produce a new motion compounded from the determination of both.

Whatever draws or prees another is as much drawn or preed by that other. If you pres a tone with your finger, the finger is alo preed by the tone. If a hore draws a tone tied to a rope, the hore (if I may o ay) will be equally drawn back towards the tone: for the ditended rope, by the same endeavour to relax or unbend it self, will draw the hore as much towards the tone as it does the tone towards the hore and will obtruct the progres of the one as much as it advances that of the other. If a body impinge upon another, and by its force change the motion of the other; that body alo (becaue of the equality of the mutual preure) will undergo an equal change, in its own motion, towards the contrary part. The changes made by thee actions are equal, not in the velocities, but in the motions of bodies; that is to ay, if the bodies are not hinder'd by any other impediments. For, becaue the motions Rh