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Aristotle · Mechanics §7.1-7.2

Sailing in Adverse Winds and Mobility of Circular Shapes

Passage 9 of 38 · Greek

Summary

This section discusses the handling of sails in unfavorable winds and the mechanical balance of the rudder and sailors, followed by an inquiry into why round shapes move easily and the three types of circular rotation.

§7.1Διὰ τί, ὅταν ἐξ οὑρίας βούλωνται διαδραμεῖν μὴ οὐρίου τοῦ πνεύματος ὄντος, τὸ μὲν πρὸς τὸν κυβερνήτην τοῦ ἰστίου μέρος στέλλονται, τὸ δὲ πρὸς τὴν πρῷραν ποδιαῖον ποιησάμενοι ἐφιᾶσιν;
Why is it that, when they wish to run before the wind although the wind is not favorable, they reef the part of the sail towards the helmsman, but let out the part towards the prow, making it a sheet?
Ἢ διότιἀντισπᾶν τὸ πηδάλιον πολλῷ μὲν ὄντι τῷ πνεύματι οὐ δύναται, ὀλίγῳ δέ, ὃ ὑποστέλλονται.
Or is it because the rudder cannot resist when the wind is strong, but can do so when it is little, which is what they get by reefing?
§7.2Προάγει μὲν οὖν τὸ πνεῦμα, εἰς οὔριον δὲ καθίστησι τὸ πηδάλιον, ἀντισπῶν καὶ μοχλεῦον, τὴν θάλατταν.
Therefore the wind impels the ship, and the rudder, resisting and acting as a lever against the sea, brings it into a favorable wind.
Ἄμα δὲ καὶ οἱ ναῦται μάχονται τῷ πνεύματι· ἀνακλίνουσι γὰρ ἐπὶ τὸ ἐναντίον ἑαυτούς.
At the same time, the sailors also fight against the wind; for they lean themselves in the opposite direction.
Διὰ τί τὰ στρογγύλα καὶ περιφερῆ τῶν σχημάτων εὐκινητότερα;
Why are round and circular shapes easier to move?
Τριχῶς δὲ ἐνδέχεται τὸν κύκλον κυλισθῆναι· ἢ γὰρ κατὰ τὴν ἁψῖδα, συμμεταβάλλοντος τοῦ κέντρου, ὥσπερ ὁ τροχὸς ὁ τῆς ἁμάξης κυλίεται· ἢ περὶ τὸ κέντρον μόνον, ὥσπερ αἱ τροχιλέαι, τοῦ κέντρου μένοντος· ἢπαρὰ τὸ ἐπίπεδον, τοῦ κέντρου μένοντος, ὥσπερ ὁκεραμεικὸς τροχὸς κυλίνδεται.
A circle can roll in three ways: either along its circumference, with the center shifting along with it, as the wheel of a carriage rolls; or around the center only, with the center remaining stationary, as pulleys do; or parallel to the flat surface, with the center remaining stationary, as the potter's wheel revolves.

Notes

  1. §7.1μὴ οὐρίου τοῦ πνεύματος ὄντος — Genitive absolute expressing concession or condition, with οὔριος ("favorable") modifying πνεύματος.
  2. §7.1ποδιαῖον ποιησάμενοι — The adjective ποδιαῖος (literally "one foot long" or "foot-like") here relates to the sheet-rope (ποῦς) of the sail, meaning letting out the sheet-rope to expand the sail.
  3. §7.1ὃ ὑποστέλλονται — The relative pronoun ὃ has πνεῦμα as its antecedent, referring to the reduced amount of wind acting on the sail that the sailors obtain by reefing (ὑποστέλλονται).
  4. §7.2ἀντισπῶν καὶ μοχλεῦον — Present active participles in the neuter singular, modifying the subject τὸ πηδάλιον (rudder). They govern τὴν θάλατταν (the sea) as their direct object.

Cite this passage

Aristotle, Mechanics §7.1-7.2. Humanitext Reader, https://reader.humanitext.ai/en/text/urn:cts:greekLit:tlg0086.tlg023.humanitext-grc1:7.1-7.2

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