2(J8 FHAENOMENORFM IRIDIS 



res anguli <^'' ; ex quo pofitio Iridis cognorcitur , (equenti 

 modo determinentur , \t fit : 



pro numero reflex. i,^^— 4$-2(t) 1:12(2$ <p) 



2,^^— TT- 6d-f-2(p)— 7r-2(3^Cpt) 

 3,^^=^:277-8 0-i-2Cl)=:27r- 2(4^ -C|>) 

 ^j^-^ziSTr-ioe-H^Cp-STr 2(50 Cp) 

 5 , ^^-4.77- 1 2 $ H- 2 Cp=47r - 2 (6 $ CJ)) 

 (J, ^^z 5 TT- 1 4O -i- 2Cp-5 Tt- 2(70 Cpjetc. 



Ex his facile perfpicitur , fi ^^^7r> Iridem inter fo- 

 lem et fpedatorem adparere debere ; at fi ^^^, vel 

 ^^ 2 7r, et exceffus eft minor ^tt, Iris ita videbitur, vt 

 fol a tergo fpedatoris exiftat , quod ex (equenti tabula 

 clarius patebit , vbi omnes cafus in his formulis contenti 

 exponuntur. 



Cafus , quibus fpedator 

 medium locum tenet. 

 <>07r 



<>;>27r 



<^ > 4 7r etc. 



Cafus vbi Iris medium 

 locum tenct. 



^> ^ 



^>l7r 

 «^^STr 

 <? > i 7r etc. 



(eu quod eodem redit , omittendo ott, 7r, 2 7r, sttj 

 4 7r etc- 



Iris in medio <^> l7r; ^>>f 7r; ^>|7r- <^>> rTr; etc. 

 Sped. inmedio^>|7r; <^>|7r; ^>^'7r;^> vtt ; etc. 



38. Inuenta hoc modo pofitione Iridis , quanti- 

 tas anguli amplitudinis ^ cx his forinulis determina- 

 bitur 



Pro 



