474- DE TELESCOPIIS 



\ti opportet: vt autem rcpraercniatio ab omni mar- 

 gine colorato liberctur , iatisficri opportct huic ae- 

 quationi 



f 3. Statiin nunc vidcamus, an campo appa- 

 renti maximum valorem conciliare liceat , id quod 

 pracftarctnr, fi denotante ^ maximum valorcm,quem 

 littcrae tt, 71' et ii" recipere poffunt, ponerctur . 



t: — -^ , 71' — + ^ ct 7t'' — — ^ 

 tum enim prodiret 



— -t- -i5- — M ^ fum.to M — -^ 



ex quo valore determinatnr diftaniia oculi pofl: vl- 

 tiraam ientem — r^ , quam ergo rarirer pofitiuani 

 efle neccffe eft, quia aliocjuin campus aflignatus ab 

 oculo confpici non pofict :, His igitur pofitis dc- 

 ftructio raarginis colorati hanc exigit aequationcm 



F^^pa~paR — I a « q.r 



C.arn5qi:o §• 4« 0.11'^ littcmrum P, Q. et R binae de- 



r >> o bent effe negatiuae , fumamus primo litteram P eflTc 



pofitiuam , vnde tam Q quam R ncgatiuas efie op^ 



portetj quocirca ponamus Q^— — k atque repcrictur 



R — j^-^ , ficque debec clTc k <^ i vt fiat 



B.-fEh i^i^^^i"^ ^Q.^^r£r,- 



m 



confequentcr P — ^-^-^ ^, quia igitur 



P — ^il' ;« et P Qz= - (i - /:) w ob 



7r = -^, 7t'^ + ^, tt"--^ ct Cp^M^; 



repc- 



