IN ORIS SEFTENTRIONALIBVS. 431 



cxiftentibus PczzAol, pczzaa; vnde (iib his condi- 

 tionibus ex obferuatione fixae verfus auftrum altitudo 

 Poli pR colligitur. E contrario ex obferuatione fixae 

 polaris verfus boream , loco PR primum acquiritur 

 ^R propter refradlionem P^, quae altitudini vcrae PR 

 refpondet , et deinde ttR propter errorem Qnadrantis 

 ^TT, ita Yt nunc eleuatio Poli ex obferuatione conclu- 

 datur ttR, exiftente bii—pc-zzcLa-zz errori Quadrati- 

 tis vero. Si iam per methodum fuperiorem inueniri 

 deberent eleuatio Poli et error Quadrantis , fumendus 

 eflet numerus arithmetice proportionalis medius inter 

 ^R et 7rR, quem ponam QR, exiftente pQ^iQTr 

 zz^pT:^ et tunc iudicaretur Q^R eleuatio Poli, ^p^K 

 "vel p Q autem error Quadraniis \ cum e contrario eleua. 

 tio Poli vera fit PR, error Quadrantis verus pc^ vel 

 hit^ vel a.a. Quo pado foret ex negleda refradionum 

 aberratio eleuatwnis Foli PQ(=:PR-QR)', et aber- 

 ratio erroris Quadrantis zzpc—pQ. Vtramque defi- 

 niiimus per refradiones negledas Aa, Vb. 

 Eft nempe PQ=pQ-/)P 



ob 



zzilp^n-pc-^Vv' 



pQ^^lpTt, €t pV^pc- 



-Vc. Eft porro 



pr-^pc-^-cn 





zzpc-^-biz — hc , 



ob cn. — h^n — bc 



•a^^pc—bc , 



ob mbzzpc 



zz^.pc-Vb-Vc » 



ob bc^Vb-^^^e 



ip^n-pc-Wb-lVc; 





vnde V(^:z:pc-\Vb- 



iVc-pc-^-Ve 



zziVc-lVb 





zz^.Aa-kVb 



, ob VczzlAsl, 



Mm^ 



