EXTERIMENTi ET EXTLICATIONES. 197 



cum fiium habeat in diftantia dimidii radii concauitatis : 

 debebit focus hic dftare a punclio D 64.^, part. qui nu- 

 merus cum imiento per Experimentum , 72 , fttis bene 

 congruit. Obuerja autem Soli parte plana diffae Lentis^E^& v vit, 

 nullus generabatur jocus , Jed debilis fplendor latus , de quo 

 itenim manifeftum eft y eum generaturn efle a reflexione 

 m planitie Lentis orta» 



Vroblema IV* 



Pertranfeat corpus A medium AEP : aequabiliter ce- &&*> 

 kritate m , medium EFG vero cderkate n - f quaeritur quam 

 viam hoc corpus A (equi debeat ,, vt ex A irf H ,-, recliam) 

 LC attingendo r perueniac tempore breuifTimov 



Solutio* 



Sit hoc via quaefita AE , EF v FG » GH , et de^ 

 raiffis ex A , H , et F perpendiculis in TKC re&am^, 

 quae fint AS , HT , et FV , ponantur TSzza , ASzz^ 

 WT—c, CS~e, CD.r DB— r :p ES=^ , EV=», VG=A; 

 eritque GT—a—t-u—x , CV~e-\-t-\-u , et VF:=: pe-\- 

 pt-\-pu , ob Similia- Triangula CDB et CVF $ ex his> 

 eruitur : 



AE—V(b T -i-t 2 } 



EF—V(p 2 e 2 -±-2p*et-hp r t*-i- 2p 2 eu-\- 2p 2 tu-\-p*u 2 -+-u 2 ) 

 ¥G—V(p 2 e 2 -\-2p 2 et-\-p 2 f 2 -\-2p 2 eu^\-2p 2 tu-\-p 2 u 2 -\-x 2 } 

 GR—V\a 2 -zaf-\-t 2 - 2au-2ax-\-2fu-\-2tx-\'U 2 '-\-2ux-\-x 2 -\-c' t '} 

 confequenter erit tempus per AEzz^ ; tempus perEF— 

 ~ j tempus per FG~ ¥ -~ ,, et tempus per GH~ ~ , ad<~ 



B b $ m$& 



