# Opticorum recensio Theonis νϚ΄.

Euclid, Opticorum recensio Theonis, νϚ΄.. Ancient Greek.

Canonical: https://interlinea.aeterna-institute.org/library/greek/euclid/opticorum-recensio-theonis/%CE%BD%CF%9A%CE%84.

Ὅσα μὴ ἐν τῷ αὐτῷ ἀποστήματι κεῖται μὴ παρ άλληλα κείμενα τῶν ἄκρων μὴ κατάλληλα κειμένων τῶ μέσων μηδὲ ἐπʼ εὐθείας ὄντων, τὸ ὅλον σχῆμα ὁτ μὲν κοῖλον, ὁτὲ δὲ κυρτὸν ποιεῖ. ὁράσθω γὰρ τὰ Β, Γ, ∠ τοῦ ὄμματος ἐπὶ τοῦ Γ κειμένου, καὶ προσπιπτέτωσαν ἀκτῖνες αἱ ΚB, ΚG Κ∠. οὐκοῦν τὸ ὅλον σχῆμα κοῖλον ἂν δόξειεν εἶναι. μετακινείσθω δὴ πάλιν τὸ ὁρώμενον καὶ ἔγγιον κείσθω τοῦ ὄμματος. οὐκοῦν τὸ ∠ΒΓ δόξει κυρτὸν εἶναι.

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Euclid, Opticorum recensio Theonis, ed. Johan Ludvig Heiberg, Heinrich Menge. 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/tlg1799.tlg010.local001/.