thcilliinc dctcrminatur. DiKflis enim ex centro C radiis 

 C/etCg, fi dicantur anguli ACf—i!, et ACg = ?/, 

 ita vt angulus fCg — 7j-^y erit diameter circuli mino- 



ris, hoc cd chorda /g - 2 fin. 1^^ vnde ob OF--^ 



ct Og—^ cof. i 7/ erit ^,,;,,. 



2 fin ^?^:^ ' ■ ' • 



F G - ——--1-— =1 2 (tang. | ^/ - tang. i ^ » 



COl. i 4 Col. ; 7) 



Tti rcquiritur. Eft enim _ ^^ _ , . ^^ ,^ ^^ ' 



A F 1= 2 tang. ^ <^ et A G r= 2 tang. T?; , 

 crgo FGzzAG-AF. 



§. 8. Quaeranttlr' areae fuperfidei cirdularis in 

 fphaera et in proiecflione , eritque poftcrior area ' 



— TT { tang. ; ;; - tang. ]^)% 

 pro altera vero, ob A O = 2 ct ^^— i-cof:^, erit 

 haec area i^ 271 (i — cof. ^^). Quod fi igitur n.iruaru^ 

 ^ — _7/, erit pro cono recflo, cuius axis eft reda AO, 

 area lupeificiei Iphaericae ab hoc cono rcfedae 



£ TT ( I — cof. 7/) — 4. TT fin. l if 

 et area bafeos, feu circuH in proiecflione — 4^ tang. ' -ki' ; 

 crgo (unt areae fuperficici proicdac et proicdionis in ra- 



— cof. : 77' : I. Hmc fi 'r) — 90% haec 



tione 



col i Vi' 



ratio erit 1:1 — 1:2. 



Tab V § 9. Sit iam p pHus terrae cinsque dif^anfia a 



Fig. 5." zenith A, feu arcus A p z^ h ct radius circuh pa.nUcU 



curui- 



