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plained themselves on this head, just as the moderns 

 do, excepting only the terms of centripetal and cen- 

 trifugal ; instead of which, however, they used what 

 was altogether equivalent. They also knew the ine- 

 quality of the course of the planets, ascribing it to 

 the variety of their weights reciprocally considered, 

 and of their proportional distances. 



3. I will not expatiate upon Empedocles' system, 

 in which some have thought the foundation of New- 

 ton's was to be found ; imagining, that under the 

 name of love, he intended to intimate a law, or 

 power, which separated the parts of matter, in order 

 to join himself to them, and to which nothing wa 

 wanting, but the name of attraction. One sees also, 

 that by the name discord, he intended to describe 

 another force, which obliged the same parts to re- 

 cede from one another, and which Newton calls a 

 repelling force. But 1 leave Em,pedocles 3 and pass 

 on to passages more deserving notice. 



4. The Pythagoreans and Platonics, treating of 

 the creation of the world, perceived the necessity of 

 admitting the force of two powers, viz. projection 

 and gravity, in order to account far the revolution 

 of the planets. Timaeus, speaking of the soul of the 

 world, which puts all nature in motion, says that 

 God hath endowed it with two powers, which in 

 combination, act according to certain numeric pro~ 

 portions. Plato, who hath followed Timaeus in his 

 natural philosophy, clearly asserts that God had im- 

 pressed upon, the planets a motion which was the 

 most proper for them; which couU be nothing else 

 than the perpendicular motion, wnich has a tendency 

 to the centre of the universe^ that is gravity ; and 

 what in this case coincides with it, a lateral im- 

 pulse, rendering the whole circular. And Diogenes 

 Laertius, alluding in all likelihood, to this passage of 

 Plato, says at the beginning, the bodies of the 

 universe were agitated tumultuously, and with a 



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