GENERE EX SEX LENT. COMPOS. 199 



6. Hinc porro deducuntiir lcntium intcrualla 

 AB— a-f-^=:Aa 



BCr^e-f-^-33A.,4fM 



E F nz e -i-/= A C. rt j. rirfcs = -y 

 ct pro loco oculi ¥0 — ^^^—;;^. 



Nunc vero vt colores iridis deftruantur , Theoria 

 Iianc praebct aequationem adimplendam : 



tT7=M H- 7^tT^~- o '^ndc fit 1? + - M:z 3 - $4- M 

 ideoquc tj — 3 — 2(0 — M). 



7. Gradus claritatis pcrceptae aeftimatur e:x 

 femidiametro cylindri luminofi , qui a quouis ob- 

 iedi pundo in oculum transmittitur , qui femper 



ef^j—iThi ^f ip^c claritatis gradus tum aeilimatur 

 — 400X7) claritate plena feu naturali per vnitatem 

 exprefla. * Verum ipfa apertura lentis obicdiuae , 

 feu eius femidiameter x cx hac aequationc dcfiniri 

 dcbct ; 



i__7nx^ ^■K-\-vaix-a) M(X"^+vc(i-c) 7 



t^^A^C^-O^lJ + O-M^^^A^C^lj^^-O + M)] 



"vbi^ 



