# De utilitate mathematicae 189

Theon Smyrnaeus, De utilitate mathematicae, Paragraph 189. Ancient Greek.

Canonical: https://interlinea.aeterna-institute.org/library/greek/theon-smyrnaeus/de-utilitate-mathematicae/189

δῆλον δὲ ὡς οὐδὲν διαφέρει πρὸς τὸ σώζειν τὰ φαινόμενα, τοὺς πλάνητας κατὰ τῶν κύκλων, ὡς διώ- ρισται, λέγειν κινεῖσθαι, ἢ τοὺς κύκλους φέροντας τὰ τούτων σώματα αὐτοὺς περὶ τὰ ἴδια κέντρα κινεῖσθαι· λέγω δὲ τοὺς μὲν ἐγκέντρους, φέροντας τὰ τῶν ἐπικύ- κλων κέντρα, περὶ τὰ αὐτῶν κέντρα κινεῖσθαι ὑπεναν- τίως 〈τῷ παντί〉, τοὺς δὲ ἐπικύκλους, φέροντας τὰ τῶν πλανωμένων σώματα, πάλιν περὶ τὰ αὐτῶν κέντρα, οἷον τὸν μὲν μλνξ ἔγκεντρον φέρεσθαι περὶ τὸ θ, τοῦ παν- τὸς καὶ ἑαυτοῦ κέντρον, ὑπεναντίως τῷ παντί, φέροντα ἐπὶ τῆς αὐτοῦ περιφερείας τοῦ 〈ἐπικύκλου τὸ〉 μ κέν- τρον, τὸν 〈δὲ〉 εζηκ ἐπίκυκλον ἔχοντα τὸν πλανώμενον κατὰ τὸ ε φέρεσθαι πάλιν περὶ τὸ μ κέντρον, ἐπὶ μὲν ἡλίου καὶ σελήνης ἐπὶ τὰ αὐτὰ τῷ παντί, ἐπὶ δὲ τῶν ἄλλων καὶ τοῦτον ὑπεναντίως τῷ παντί· σώζεται γὰρ οὕτως τὰ φαινόμενα.

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Theon Smyrnaeus, De utilitate mathematicae, ed. Eduardus Hiller. Text: The Greek Library, from the Perseus Digital Library and other open sources, CC BY-SA 4.0. Changes: apostrophes normalised and the text divided into reading sections by Interlinea.
License: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/). Source: https://thegreeklibrary.pages.lisn.upsaclay.fr/works/tlg1724.tlg001.local001/.