Chap. I. ANTIENT METAPHYSICS. 331 



Thus, I think, I have proved, that tlie progreffive Motion of the 

 Planet, in its Orbit, is mechanical ; and, further, that it is not perfed of 

 the kind. But there is another Motionof the Planet, different from the 

 Progreffive Motion, which is alfo mechanical, according to Sir Ifaac's 

 Syftcm, and liable to the fame dcfedl : The Motion I mean is that 

 on its Axis, which the Newtonians fay is alfo produced by a Pio- 

 jedile Impulfe, fo that the Planet being once fet a fpinning, like a 

 top, continues for ever to do fo, without any agency of Mind*. 

 This makes the Machinery of the Heavens not a little complicated : 

 And, if the Planetary Motion, in all its parts, is underftood to be pro- 

 duced by Bodily Impulfe, there muft, I doubt, be three Bodies em- 

 ployed ; one to give the progreflive Impulfe, by which the Planet is 

 carried round in its Orbit ; one to give it the Centripetal Motion ; 

 and a third to give it the Motion on its Axis. 



Nor do I think that the matter will be much mended, by fuppo- 

 fmg, as I believe all the Newtonians now do, that one of the Mo- 

 tions, viz. the Motion of Gravitation, is produced by the conftant 

 agency of Mind : But, on the contrary, I think it makes the Ma- 

 chinery more perplexed and intricate, and Sir Ifaac's Syftem much 

 lefs regular and uniform than it would otherwife be ; for, according 

 to this hypothefis, two parts of the Motion of the fame Planet are 

 produced by Bodily Impulfe, and the third part by Mind. So 

 complicated a Syftem feems to be far removed from that wonderful 



T t 2 ^ fimplicity 



• Sir Ifaac, in his explanation of his Firft Law of Motion, has thefe words : 

 ' Tiochus, cujus partes cohaerendo perpetuo retrahunt fefe a motibus reQilineis, 



* non ceffat rotari nifi quatenus ab ai:re rctardatur." And this theory of the Mo- 

 tion of a wheel he applies to^the Motion of the Planets in the following words : 

 ' Majora autem planetarum ct cometarum corpora, motus fuos, et progrefTivcs et 



* circulares, in fpatiis minus refiflentibus fa£los, confervant diutius.' But, as to 

 the duration of the Planetary Motion, he exprefll-s himfelf much more ftrongly in 

 h\& Scholium Generate : ' Corpora omnia in iflis fpatiis liberrime moveri debent ; 

 ' et propterea Planetae et Cometae, in Oibibus fpecie et pofitione datis, fccundum 

 ' leges fupra expofitas perpetuo revolvi.' 



