148 E V O L V T I O 



quibuscum normnlcs ad curuam in in et M diiclas 

 et in C concurrenres comparemus. Qiiia vero eft 

 angulus MTC=ATC=:9o°-a), ob MT = T erit 



in fubfidium vocando rclationem inter tangcntes 

 m t -rzt ct MT — T fupra inuciuam. Tum vcra 

 hinc porro habctur : 



jm. co jln. tjj coj, oj '' d w 



vnde auferatur interuallum 



T mzzt tang. (o — '-^|iii^ , vt remaneat 



cx quo perfpicuum crt hanc rcdam w C ipfi radio 

 ofculi in m aequari , idcoquc puuiflum C reperiri in 

 euohita curuac quacfitac. 



14. Cum normalis m C vtpotc radius ofculi 

 euokitam curuac quacfitae in C tangat , normaUs 

 verc MC per idem pundum tranlcat , ca hic cuo- 

 luram fecabit , nifi euoluta in vnicum puncflum 

 concentretur , vti eucnit in circulo. Qunre fi prae- 

 ter circulum ahae curuae noftrae quaeftioni fatis- 

 faciant , carum cuolutas ita comparatas eflc oportct, 

 vt fi normahs m C cuolutam tangat in C, normalis 

 M C candcm hic fccct produda vcro alibi tangat , 

 ficque ncccfle q.[\ , omncs euohitac t.ingcntcs candcm 

 fimul ahcubi intcrfccarc, quod quomodo in omnibus 

 tangcntibus contingcrc polht , haud pcrfpicitur , nifi 



forte 



