==(85) = 



clcl poflerloris eft Sphaera, prioris Comis nrque Cylindrus. 

 Quantuinuis eniin hetcrotjcneae lint fupcrficics curuac ac pla- 

 rac, rinc dubio tamcn tanta non intcrccdit hctcrogcnciras in- 

 tcr Conum Cylindrunnie et Planuin, quanta intcr Sphacram 

 rianumquc. Cuin itaquc mcthodus in omnibus fcientiis rc- 

 ccpta iubcat, rcm arduain fucediuc dcclararc, ct velut in ac- 

 quationibus Algcbraicis complicatis nouam introduccre incogni- 

 tam, inquircrc volui, quidnam efTct refultaturuin, fi fupcrficics' 

 Sphaerica in Conum Sphacram tangcntcm proiiccrctur, tumque' 

 Conui in Planuin cuolucrctur. Quanquam eniin ilhi mcthodus 

 haud praebcat proiccftioncm, qune cctcris vfitatis palmain prae- 

 ripiat, tamen ceu disquifitio gcomctrica de Coni cum Sphaera 

 coniun<ftione potefl: confidorari, quam co magis cum Acade- 

 mia coinmunicarc conatus fum, cnin muniis ab Acadcmia mi- 

 hi impofitum huiusmodi disquifitioncs praccipue a me pofcere 

 Yideatur. 



§. 2. Sit itaque APQ hemifphacrium, AQ Acqua-Tab. III. 

 tor, P Pohis , E^ Parallclus pcr mcdium Zonac proiicicndae ^'S- '• 

 tranfiens, in quo Parallclo Sphacram tangat Conus Epe^ at- 

 quc quoduis Sphacrae punduin r/ proiiciatur in D \bi radius 

 Cd Cono occurrit: ponitur igitur oculus in ccntro C. Hinc 

 Ilatim patct, qucmcunquc Mcridianuin PE proiici in lincatn 

 rc(ftain />E, quac clt coni latusi proicclio cniin eft fcdio co- 

 nica pcr Coni a\cin p C tranficns. Parallcli vcro in circuios 

 bafi coni parallclos proiiciuntur; eft eniin Paralicius ^5 hahs 

 coni dC^^ qui prolongatus vbi altcri cono Epc occurrit, 

 dctcrminat paralicli proieclioncin. Ponatur nunc latitudo Paral- 

 lcli incdii AE— X, Ar/z:j3: erit Ep::cor. X, C/) = cofcc. X, 

 E I) = tang. (|3-X), p D =^_^1|_^, allamto radip.^phac- 

 rac - I. Eft euim ji^ -j^^ ^ 



L 3 pD 



