Chap. IV. ANTIENT METAPHYSICS. 373 



mafs we can fuppofe ; and this fluid to be within another fluid, our 

 air, and to be conftantly traverfing it, without afietting any of our 

 fenfcs. 



But, befules Gravitation, there are many other Motions upon this 

 Earth, alfo of Bodies unorganized, fuch as the Motions of Mag- 

 netlfm, Eledrlcity, and of the fmall particles of Matter obferved 

 by chymifts, which cannot be accounted for by Fluids, any more 

 than the Motion of Gravitation: For, as the Motions of thefe 

 Bodies are only occafional, there muft be both a Creation of a Fluid, 

 to account for the beginning and continuance of the Motion, and 

 likewlfe an annihilation of it, to account for the ceffation of it. 



As to the Motion of Animals from place to place, I believe there 

 is no philofopher in Britain that thinks It can be accounted for by 



Trufion, or by any Mechanical Caufe whatfoever. And fo much 



for this way of Body moving Body by Trufion. 



As to the Motion by Impulfe, I hope I have fliown to the reader's 

 fatisfadion, thatitmufl: be carried on by Mind : So that the onlyque- 

 flion at prefent is, What Motions here on Earth are begun by Impulfe ? 

 And, in xhtfrjl place, I think it is evident that Gravitation here on 

 Earth is not the effedl of any Impulfe, or Original ImprefTion, upon 

 the Body ; though that opinion alfo has been endeavoured to be de- 

 fended. It has taken its rife, as I imagine, from the notion of the Pla- 

 nets being moved originally by Impulfe, and their Motion continued 

 by virtue of the fame Impulfe. But, even fuppofing the Motion of the 

 Planets to have been begun and to be carried on in that way, if their 

 Motion were flopped the fame Impulfe certainly would not be fuf- 

 ficlent to make them recommence the Motion, but a new one would 

 be abfolutely necefliary. In the fame manner, when a ftone falls to 

 the ground, is taken up, and falls again, the fame Original Impulfe 



will 



