= (lop) == 



tum tcnucrit EF, ciiisquc longitudincm EF ftatuimus zz: a. 

 Hinc vcio clapfo tcmpoic rzir acccpcrit figuram EYF, quac Tab II. 

 fit arcus circularis rcclam E F pro axe alTumtam tangcns in ^'g- ^- 

 ipfo puncf.o E, ita vt flli tcrminus E pcrpctuo maneat inimo- 

 tus. Radius aiucm hnins circnli fit E () ~ r, fundio quae- 

 cunquc data tcmpori^^ r, vndc nccclic cft vt pofito / = illa 

 funclio r cuadat infinira. Sit nunc E Y porrio quaccunque 

 indcfinita fili r/, duaoquc radio OY crit angulus EOYri-, 

 cuius finus crit - - — ^- , cofinus vcro i — -^ , vnde coor- 

 dinatae E X = .v et X Y rr j ita pcr binas variabiles s tt t 

 cxprimcntur, vt fit x =: r fin. -- ct j — r (i — cof. -^). Qui- 

 bus pofitis quaeflio folucnda huc rcdit: vt inucrtigcntur vires 

 P ct Q, quae filo talcm n^otuni qualcm hic dcCcripfimus in- 

 duccrc valcant. Quac quidcm quacltio maximc adhnc crit in- 

 dctcrminata, proptcrca quod pro motu dctcrminando vnicam 

 tantum habcmus acquationem: 



^g(^^j)f^ds-^ g (^)f(ldszz(^f)fds (\\^-) - (ipfds fii>), 

 "vndc alterutra quantitatum P et Q arbitrio nollro relinquctur. 



Euolntio formularum 



in hanc acqiiationcm ini>rcdicntium. 



§. 13. Cum littera r fit fundio tcmporis / tantum, fum- 

 ta fola s variabili impctrabimus has formulas (— ) — cof i et 



(->)r=fin.i-, vnde Iponte fit (^J- -{- (^^Y = i , vti rci^ia- 

 tura poftulat. Sumto autcm folo tcmpore / variabili ponamus 

 breuitatis gratia ^f — r D/, ac diffcrentiando rcpcriemus 

 C-^) = r' fin. -i — ^^ cof. -i et 



«" ' r r r 



(j>; :=zr\x~ cof -1) — ii: fin. '- . 



^' r ' r r 



O 3 §• '+• 



