puncflo A cdu(flas traiicit, quae crgo manifcflo cft Spiralis 

 logarithmica. Vndc patct, fi anguhis intcrfcctionis debcat cffe 

 redus, idcoquc 5roo, tum Itaiim forc x \/ (c c -{- a a) - b c ^ 

 vndc colligimus g ~ ^^ bb—xx^ ^^^ij y.^ioj. j,^ acquatione ge- 



nerah r i^ ~ fubrtitutus pracbct acquationcm pro Traicdoriis 



jfrziy\bb — A-.v); vndc patct, quod quidcm pcr fe eft per- 

 fpicuum, Traicdorias cflc circulos ccntro A, radio ^, dcfcriptos. 



Exemplum 2. 



^. 14. Sint curuac (ccandae omncs circuli ex codcm -y^^ j 

 ccntro C, radio \ariabili a dcfcripti, pro quibus crgo eft Fig. i. 

 y zzi y(^a a — x x) , vnde fit dy — """'^^^ •> t]uae acquatio 



cum formula gencrali dvz=zpdx-]-qda comparata, praebet 



p rr —^i^ et ^ zr - — ? , 



idcoque i -\- p p — ----^^^-— . Quamobrcm acquatio pro Tra- 

 icdoriis, poncndo tang. a — J, erit 



aia S a a ^ X ■filie 



> ^aa — xxt i5 x-t-i loo — jc jc,) jy laa— j; j:)' 



d„ S a dx 

 a .- ; > 



X-f- ) 10 O — XX> 



Hinc igitur, fi angulus interfccftionis debeat eflc rciftus, feu (^300, 

 crit 5a~-^^, ideoque a-l^x^ qui valor in aequatione ge- 

 nerali y ~ \^ (a a — x x) fubftitutus dat y zz: x Y^b b - 1) ^ liuc 

 j-c X , Quae aequatio in fe complcclitur omnes redas e cen- 

 tro C cduclas. 



§. 15. Pro angulis autcm nbhquis ncquatio inucnta 



hac forma rcpracfcntctur : 3 a / (a ^ — .v.v) rz 5 {adx — xda); 



vbi notctur, formulam adx — xda intcgrabilcm reddi, fi di- 



uidatur per funcf^ioncm homogcncam duarum dimcnfionum ip- 



farum a ct x. Diuidatur igitur haec acquafio pcr jv^C'"' "■*"■*")» 

 vt prodeat jj __ y^ojr— x.y<,! ^ p-.jj. ^^^-^^^^ x — av, et aequa- 



B 2 tio 



