Chap. XIX. ANTIENT METAPHYSICS. 275 



and forces. But what is the caiife of thefe motions, and what is the 

 motive force, is an inquiry that belongs to phllofophy, and to the firfl: 

 philofophy, whofe fubje(Sl is the univcrfe, and the principle of all pro- 

 du(5tion and generation in it ; an inquiry, for which the fludy of geo- 

 metry and mechanifm will not alone qucdify any man. 



Sir Ifaac went Aill further out of his province, when he inquired 

 concerning the origin of other motions which he obferved among the 

 fmaller bodies, fuch as repulfion, magnetlfm, and eledricity. In mea- 

 furing thofe motions, he did not find that his geometry and mechanics 

 could be of any life to him ; he fhould, therefore, have either let them 

 alone altogether, or, if he was to inquire concerning the caufe of 

 them, he fhould have olcribed them to mind, which, one (hould have 

 thought, was moft natural for a Theifl:, fuch as Sir Ifaac certainly 

 was, to have done, as they could not be accounted for from any me- 

 chanical caufe. 



But, inftead of mind, he employs a fuhtile fp'int^ pervading 

 all bodies, by which he accounts, not only for the attradion, co- 

 hefion, and repulfion of the fmall particles of matter, and for all 

 the phaenomena of eledricity, but for fenfation, and the fpontaneous 

 motion of animals *. Now, \X\\^ fuhtile /pint is more aa occult caufe 



M m 2 than: 



His words are, Adjicere jam liceret nonnulla de fpiritu qUodam fubtilifTimo, cor- 

 pora crafla pervndente, et in iifdem Jatente ; cujus vi et a£tionibus particulae corporum 

 ad minlmas diflantias fe mutuo attrahunt, et contiguac fa<^ae cohacrent ; et corpora 

 cledrica agunt ad diftantias majores, tarn repell^rido quam attrahtndo corpufcula vi- 

 cina; et lux emittitur, reflt6i:itur, rcfringitur, infleclitur, et corpora calefacit ; et {<cx\. 

 fatio omnis excitatur, et membra animalium ad voluntatem moventur, vibratioiiibus 

 fcilicet, bujus fpiritus per foiida nervorum capillamcnta ab externis fenfuum organis ad 

 cerebrum, et a cercbro in mufculos, propagatis. Sed haec paucis exponi non poflunt • 

 neque adefl fufficicns copia experimentorum, quibus leges aclionum bujus fpiritus ac- 

 curate determlnari et monftrari debent — Injine Principiorum. 



