§3.4#2νῦν δ᾿ ὅλα μὲν οὐ γίγνεται τοιαύτην ἔχοντα τὴν ἔμφασιν, οὐδὲ κύκλῳ, μικρὰ δὲ καὶ κατὰ μόριον, αἳ καλοῦνται ῥάβδοι, ἐπεὶ εἰ συνίστατο τοιαύτη ἀχλὺς οἵα γένοιτ᾿ ἂν ὕδατος ἢ τινος ἄλλου μέλανος, καθάπερ λέγομεν, ἐφαίνετο ἂν ἡ ἶρις ὅλη, ὥσπερ ἡ περὶ τοὺς λύχνους.
But now they do not occur as wholes having such an appearance, nor in a circle, but small and in parts, which are called "rods"; since if there were condensed such a mist as would arise from water or some other dark object, as we say, the rainbow would appear as a whole, just like that around lamps.
περὶ γὰρ τούτους τὰ πλεῖστα νοτίων ὄντων ἶρις γίγνεται τοῦ χειμῶνος, μάλιστα δὲ δήλη γίγνεται τοῖς ὑγροὺς ἔχουσι τοὺς ὀφθαλμούς· τούτων γὰρ ἡ ὄψις ταχὺ δι᾿ ἀσθένειαν ἀνακλᾶται.
For around these lamps, for the most part, a rainbow occurs in winter when south winds blow, and it becomes especially clear to those who have moist eyes; for their vision, because of its weakness, is quickly reflected.
γίγνεται δ᾿ ἀπὸ τε τῆς τοῦ ἀέρος ὑγρότητος καὶ ἀπὸ λιγνύος τῆς ἀπὸ τῆς φλογὸς ἀπορρεούσης καὶ μειγνυμένης· τότε γὰρ γίγνεται ἔνοπτρον, καὶ διὰ τὴν μελανίαν· καπνώδης γὰρ ἡ λιγνύς·
And it occurs both from the moisture of the air and from the soot flowing off from the flame and mixing with it; for then it becomes a mirror, and also because of its blackness, for soot is smoky.
τὸ δὲ τοῦ λύχνου φῶς οὐ λευκὸν ἀλλὰ πορφυροῦν φαίνεται κύκλῳ καὶ ἰριῶδες, φοινικοῦν δ᾿ οὔ· ἔστι γὰρ ἥ τε ὄψις ὀλίγη ἡ ἀνακλωμένη, καὶ μέλαν τὸ ἔνοπτρον.
But the light of the lamp appears not white but purple in a circle and rainbow-like, but not crimson; for both the reflected vision is small, and the mirror is dark.
ἡ δ᾿ ἀπὸ τῶν κωπῶν τῶν ἀναφερομένων ἐκ τῆς θαλάττης ἶρις τῇ μὲν θέσει τὸν αὐτὸν γίγνεται τρόπον τῇ ἐν τῷ οὐρανῷ, τὸ δὲ χρῶμα ὁμοιοτέρα τῇ περὶ τοὺς λύχνους· οὐ γὰρ φοινικῆν ἀλλὰ πορφυρᾶν ἔχουσα φαίνεται τὴν χρόαν.
And the rainbow from the oars when they are lifted out of the sea occurs in the same relation of position as the one in the sky, but in color it is more similar to that around lamps; for it appears to have a purple color, not a crimson one.
ἡ δ᾿ ἀνάκλασις ἀπὸ τῶν μικροτάτων μὲν συνεχῶν δὲ γίγνεται ῥανίδων· αὗται δʼ ὕδωρ ἀποκεκριμένον εἰσὶν ἤδη παντελῶς.
And the reflection occurs from very small but continuous drops; and these are already entirely separated water.
γίγνεται δὲ κἄν τις λεπταῖς ῥαίνῃ ῥανίσιν εἴς τι τοιοῦτον χωρίον ὃ τὴν θέσιν πρὸς τὸν ἥλιον ἐστραμμένον ἐστὶ καὶ τῇ μὲν ὁ ἥλιος ἀνέχῃ τῇ δὲ σκιάζῃ·
And it also occurs if someone sprinkles fine drops into some such place whose position is turned toward the sun, and on one part the sun shines, while on another it is in shadow.
ἐν τῷ τοιούτῳ γάρ, ἐὰν εἴσω τις ῥαίνῃ, τῷ ἑστῶτι ἐκτός, ᾗ ἐπαλλάττουσιν αἱ ἀκτῖνες καὶ ποιοῦσι τὴν σκιάν, φαίνεται ἶρις.
For in such a place, if someone sprinkles inside, to one standing outside, where the rays overlap and produce the shadow, a rainbow appears.
ὁ δὲ τρόπος καὶ ἡ χρόα ὁμοία καὶ τὸ αἴτιον τὸ αὐτὸ τῇ ἀπὸ τῶν κωπῶν· τῇ γὰρ χειρὶ κώπῃ χρῆται ὁ ῥαίνων.
And the manner and the color are similar and the cause is the same as that from the oars; for the person who sprinkles uses his hand as an oar.
ὅτι δὲ τὸ χρῶμα τοιοῦτον, ἅμα δῆλον ἔσται καὶ περὶ τῶν ἄλλων χρωμάτων τῆς φαντασίας, ἐκ τῶνδε, δεῖ γὰρ νοήσαντας, ὥσπερ εἴρηται, καὶ ὑποθεμένους πρῶτον μὲν ὅτι τὸ λαμπρὸν ἐν τῷ μέλανι ἢ διὰ τοῦ μέλανος χρῶμα ποιεῖ φοινικοῦν, δεύτερον δ᾿ ὅτι ἡ ὄψις ἐκτεινομένη ἀσθενεστέρα γίγνεται καὶ ἐλάττων, τρίτον δ᾿ ὅτι τὸ μέλαν οἷον ἀπόφασίς ἐστιν· τῷ γὰρ ἐκλείπειν τὴν ἴψιν φαίνεται μέλαν· διὸ τὰ πόρρω πάντα μελάντερα φαίνεται, διὰ τὸ μὴ διικνεῖσθαι τὴν ὄψιν.
And why the color is of this kind will at the same time be clear also concerning the appearance of the other colors from the following; for we must understand, as has been said, and assume first that a bright object in a dark one or through a dark one produces a crimson color, second, that vision as it is extended becomes weaker and less, third, that black is like a negation (for by the failing of vision it appears black, wherefore all distant things appear blacker, because vision does not reach them).
θεωρείσθω μὲν οὖν ταῦτ᾿ ἐκ τῶν περὶ τὰς αἰσθήσεις συμβαινόντων· ἐκείνων γὰρ ἴδιοι οἱ περὶ τούτων λόγοι· νῦν δ᾿ ὅσον ἀνάγκη, τοσοῦτον περὶ αὐτῶν λέγωμεν.
Now these things should be studied from what happens regarding the senses; for the discussions about these things are proper to those subjects; but for now let us speak of them as much as is necessary.
φαίνεται δ᾿ οὖν διὰ ταύτην τὴν αἰτίαν τά τε πόρρω μελάντερα καὶ ἐλάττω καὶ λειότερα, καὶ τὰ ἐν τοῖς ἐνόπτροις, καὶ τὰ νέφη μελάντερα βλέπουσιν εἰς τὸ ὕδωρ ἢ εἰς αὐτὰ τὰ νέφη.
At any rate, because of this cause, distant things appear both blacker and smaller and smoother, as do things in mirrors, and the clouds appear blacker when people look into the water than when they look at the clouds themselves.
καὶ τοῦτο πάνυ ἐπιδήλως· διὰ γὰρ τὴν ἀνάκλασιν ὀλίγῃ τῇ ὄψει θεωροῦνται.
And this is very evident; for because of the reflection they are observed with a small vision.
διαφέρει δ᾿ οὐδὲν τὸ ὁρώμενον μεταβάλλειν ἢ τὴν ὄψιν· ἀμφοτέρως γὰρ ἔσται ταὐτόν.
And it makes no difference whether the object seen changes or the vision; for in both ways the result will be the same.
πρὸς δὲ τούτοις δεῖ μὴ λεληθέναι καὶ τόδε· συμβαίνει γὰρ ὅταν ᾖ τοῦ ἡλίου νέφος πλησίον, εἰς μὲν αὐτὸ βλέποντι μηδὲν φαίνεσθαι κεχρωματισμένον ἀλλ᾿ εἶναι λευκόν, ἐν δὲ τῷ ὕδατι αὐτὸ τοῦτο θεωροῦντι χρῶμά τι ἔχειν τῆς ἴριδος.
In addition to these things, this also must not escape our notice; for it happens when there is a cloud near the sun, that to one looking at the cloud itself it appears not colored at all but white, but to one observing this very thing in the water it appears to have some color of the rainbow.
δῆλον τοίνυν ὅτι ἡ ὄψις ὥσπερ καὶ τὸ μέλαν κλωμένη δι᾿ ἀσθένειαν μελάντερον ποιεῖ φαίνεσθαι, καὶ τὸ λευκὸν ἧττον λευκόν, καὶ προσάγει πρὸς τὸ μέλαν.
Therefore, it is clear that vision, when reflected, because of its weakness, just like the dark object, makes things appear blacker, and the white less white, and brings it closer to the black.