Methodus inveniendi lineas curvas

300 DE CURVIS laminae statum naturalem, omnes oscillationum modi in sequentibus aequationibus continebuntur: I. $\frac{a}{c} = \frac{5}{4}\pi + \phi = l \cot. \frac{1}{2}\phi$ II. $\frac{a}{c} = \frac{9}{4}\pi + \phi = l \cot. \frac{1}{2}\phi$ III. $\frac{a}{c} = \frac{13}{4}\pi + \phi = l \cot. \frac{1}{2}\phi$ &c. Aequationum ergo harum prima praebebit primum eumque principalem oscillandi modum, pro quo valor anguli $\phi$ simili modo, quo supra, per approximationem reperietur. Limites autem anguli $\phi$ mox colliguntur esse $1^{\circ}, 0', 40''$ & $1^{\circ}, 1', 0''$, ex quibus per sequentem calculum verus ipsius $\phi$ valor eruitur. $\phi = $ | $1^{\circ}, 0', 40''$ | $1^{\circ}, 1', 0''$ --- | --- | --- feu $=$ | $3640''$ | $3660''$ log. $=$ | $3,5611013836 [TRUNCATED]