184 DE LEGE REFRACTIONIS 



nis. Si ig'tur angulus rcfin^rtionis y^ minor fit an- 

 gulo incidcntiLic ^, \ti fit , dum nidii ex mcdio 

 rariori in dcnfuis progrcdiuntur , f cundum hanc 

 hypothcfin radii in niedio dcnfiori \clocius moucu- 

 tur, quam in rariori. 



Coroll. 2' 



5T. Sl a denotct cilcritatem radiorum mcdiae 

 naturae in medio A, fitque rcinKftio n<cdia — w:i 

 erit V(aa-\-E]-)i2a vnde fit conlbns E-[mw-i)aa. 

 Tum \cro fi pro altero radioriuTi cxtremorum ge- 

 nere veluti rubrorum celcritas in mcdio A fit -«•', 

 et refradio rubra \occtur — r : i crit quoquc 

 E~(^r— i)fl''G'' bincqu^ {rr—i)a^ a' ~{nim— i)aa 



et f-y(n-^;^"). 



Coroll. 4. 



32. Ob Erz(7}n!i— i)aa , crit cclcritas radio- 

 rum mcdiorum in altero mcdio B, nempe b-zzmoy 

 cclcritas \ero radiorum rubrorum b^ — ra\ idco- 

 que y-y {a'a'-\-{mm- i)aa)^ (cu b' b^-bb-a^ a'-aa^ 

 Tnde diffcrcntia intcr quadrata CLlcritatum , quibus 

 radii mcdii et extrcmi in quouis mcdio moucntur , 

 cft conftans. 



Scholioii. 



33. Sit mcdium A acr, ct mcdium B vi- 

 t-rum , vt fit refradio mcdia wzz i, 55^ ct cclcri- 



