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← ExitStobaeus, Volume I

Reading language

Book I Chapter 30

Chapter 30: Rainbows and halos

On the rainbow, halos, mock suns, and rods.⁸⁸⁶

1 ⟨Aëtius⟩: Substance and appearance

Of the phenomena aloft, some arise as substantial formations, such as rain and hail; others arise as appearances, having no substantial existence of their own. For example, when we are sailing, the mainland seems to move. The rainbow, then, is an appearance.⁸⁸⁷

1 ⟨Aëtius⟩: Iris, wonder, and poetry

Plato says that people traced her descent from Thaumas because they wondered at her.⁸⁸⁸ Homer says:

As he spreads a purple cloud for mortals.⁸⁸⁹

Some also told the story that she has a bull’s head and sucks up rivers.

1 ⟨Aëtius⟩: Three paths of sight

How, then, does it arise? We see along lines, either straight, bent, or reflected: lines apprehensible by reason and without bodily substance.⁸⁹⁰

1 ⟨Aëtius⟩: Straight and bent paths

Along straight lines we see things in air, and things through transparent stones and horn, for all these consist of fine particles. ⟨Along⟩ bent lines we see things beneath water: sight is forcibly bent because the material of water is denser. This is also why, from a distance, we see an oar in the sea as bent.⁸⁹¹

1 ⟨Aëtius⟩: Reflection from droplets

The third manner of seeing concerns reflected things, such as images in mirrors. The phenomenon of the rainbow is of this kind. We must conceive of the moist exhalation changing into cloud, and then gradually from cloud into small, moist droplets. When the sun is in the west, the rainbow must appear opposite the sun: sight then strikes the droplets and is reflected, so producing the rainbow.

1 ⟨Aëtius⟩: The three colors

The droplets present images of color, not of shape. The first part is scarlet, the second sea-purple and purple, and the third dark blue and green.⁸⁹²

1 ⟨Aëtius⟩: Changes in radiance

Perhaps the scarlet arises because the sun’s brightness strikes the droplets and its radiance, reflected without admixture, produces a red and scarlet color. The second part, becoming clouded and more burned out in its radiance through the droplets, is sea-purple.⁸⁹³ ⟨For this is a weakening of the red; and, becoming clouded yet again,⟩ the dew-like moisture changes to green.⁸⁹⁴

1 ⟨Aëtius⟩: A test with sprayed water

This can be tested in practice. If someone stands opposite the sun, takes water, and sprays it from the mouth, and the droplets produce a reflection toward the sun, that person will find a rainbow forming. People with inflamed eyes also experience this when they look toward a lamp.⁸⁹⁵

2 ⟨Arius Didymus⟩: Aristotle on reflection

Aristotle’s view. Halos, rainbows, mock suns, rods, and the other phenomena that are appearances arise from the same cause. All are reflections of sight, differing in their modes, in the surfaces from which the reflection occurs, and in the conditions under which it takes place.⁸⁹⁶

2 Aristotle: Where halos appear

A halo appears around the sun and the moon, and generally around bright stars, no less by day than by night, at midday or in the afternoon; less often in the morning and around sunset. It occurs when their light shines through the surrounding air while it is hazy, so that the whole circle is seen: the halo is visible all around and round in appearance.⁸⁹⁷

2 Aristotle: Halos as weather signs

A halo that persists signifies rain; one that breaks apart, wind; and one that fades, fair weather.⁸⁹⁸

2 Aristotle: The rainbow’s extent and colors

A rainbow forms only in connection with the sun and moon. It occurs at night too, but rarely and at very long intervals. The rainbow never appears as a complete circle or as an arc greater than a semicircle. Its appearance is varied because, as sight is reflected, scarlet, green, and sea-purple color reaches us from it.⁸⁹⁹

2 Aristotle: Brightness seen through darkness

It is scarlet because something bright, seen against darkness and through darkness, produces such a hue. Thus the sun appears red to those who view it through mist or smoke; or the flame from green wood appears scarlet because much smoke is mixed with it.⁹⁰⁰

2 Aristotle: The outer and inner bands

For this reason the outermost and largest band of the rainbow displays scarlet: sight, reflected through the darkness of the cloud toward the sun in its great brilliance, apprehends a color of this kind. The second and third bands display green and sea-purple because of the weakness of sight.⁹⁰¹

2 Aristotle: The double rainbow

In general, the rainbow is an appearance of a portion of the sun or moon in a hollow cloud moistened with dew, seen along the circumference of a circle. Sometimes it is double: the second appears fainter, is consistently set over against the first, and has its colors arranged in the reverse order.⁹⁰²

2 Aristotle: The appearance of a mock sun

Mock suns and rods arise from the same cause, though the cloud is not in the same condition. When it is hazy and uniform, and also watery and dense, sight is bent back toward the sun as from a smooth bronze mirror and produces an appearance of white. For the mock sun appears similar to the sun in both color and shape.⁹⁰³

2 Aristotle: The cloud as a mirror

The uniformity of the cloud accounts for the color, and the reflection of sight for the sun’s appearance through the haze. This reflection falls all together upon something condensed, like a mirror, which is not yet water but is close to changing into water.⁹⁰⁴

2 Aristotle: A sign of rain

Hence a mock sun is also a sign of rain, and a southern one more so than a northern one, because southern air changes into water more readily than the air toward the north.⁹⁰⁵

2 Aristotle: Position and the nature of rods

Mock suns occur around sunrise and sunset, at the sides rather than above, as rods do also. The so-called rods are straight, rainbow-like appearances formed in the air through the unevenness of the reflecting clouds.⁹⁰⁶

886.“Rods,” rhabdoi, are straight streaks of rainbow-like color, defined at the chapter’s end. A mock sun, parēlios, is an appearance resembling the sun beside it; a halo is the ring described around a luminous celestial body.

887.Hypostasis here is a thing’s substantial existence, contrasted with emphasis, an appearance. The distinction concerns whether the visible phenomenon is itself a separate body. The bracketed Aëtius heading is Wachsmuth’s editorial identification of the source.

888.Theaetetus 155d. Iris names both the rainbow and its divine personification. Plato connects Thaumas, her father, with thauma, “wonder,” in a passage about philosophy’s beginning in wonder. The present report applies that wordplay to the rainbow.

889.Iliad 17.547. The Homeric text normally has irin, “rainbow,” where Wachsmuth prints nephelēn, “cloud,” in Stobaeus. It also has a different form of the verb “stretch.” The facing text and translation retain this version. The implied subject is Zeus, named in Homer’s following line.

890.The account distinguishes paths of vision from material bodies. Its subsequent explanation speaks of sight itself as bent or reflected. This terminology is retained, rather than replaced with an account of light rays entering the eye.

891.Wachsmuth supplies kata, “along,” before the second kind of line. Horn is included among materials through which something can be seen. The explanation attributes the bending of sight in water to the greater density of the medium.

892.The compressed Greek literally calls the droplets “forms not of shape, but of color”; the translation understands this as what their reflections present. Halourges, “sea-purple,” and porphyroun, “purple,” are both retained. This order differs from the scarlet, green, and sea-purple of the Aristotelian account below.

893.The printed ekkaiomenon refers to burning; “burned out in its radiance” is a tentative rendering of a difficult construction. The parallel in Pseudo-Plutarch, Placita III.5 (894e), reads ekluomenon, “weakened.” That smoother wording has not replaced the supplied edition’s Greek.

894.Heeren supplies the words in angle brackets from the parallel Placita account. The following drosizon, “dew-like moisture,” is Diels’s correction from the parallel transmitted under Galen’s name; the manuscripts here have diorizon, “that which marks off.” These editorial decisions are retained as printed.

895.Putizein means to spit or spray liquid from the mouth. The second example concerns a colored appearance seen around a lamp by affected eyes. Both examples are offered as comparisons with the atmospheric phenomenon, not as separate kinds of celestial body.

896.Wachsmuth identifies the source as Arius Didymus’s epitome, physical fragment 14. The heading names Aristotle; the report paraphrases material from Meteorology III.2-6. Its successive explanations concern the differing conditions of reflection.

897.Sphairikē, literally “spherical,” describes the halo’s appearance here. The preceding reference to seeing the whole circle supplies the context for “round”; the report treats it as an appearance, not as a solid sphere.

898.Meteorology III.3 gives the corresponding explanation in terms of continued condensation, dispersal by wind, and the failure of the moisture to condense further. These are the weather signs asserted by the ancient account.

899.“In connection with” renders peri here without making the rainbow a ring around the sun, as the halo is. The account includes the rare lunar rainbow and asserts the semicircular limit. Its three color terms and their order are preserved.

900.“Green wood” means fresh, unseasoned wood. The comparison makes the dark intervening material responsible for the changed appearance of brightness. The two examples are joined by the printed ē, “or,” rather than a conjectured “and.”

901.The differing colors are explained through a weakening of sight in reflection. “Bands” renders the successive periphereiai, the arcs or circumferences distinguished within the bow.

902.The reversal concerns the order of the colored bands in the two bows. Meteorology III.4 likewise distinguishes the fainter outer rainbow and its reversed sequence. The present report gives the description without reproducing the full optical argument.

903.The cloud acts as the reflecting surface. Wachsmuth retains katoptron, “mirror,” against Diels’s proposed deletion, observing that the passage is a paraphrase of Aristotle rather than an exact quotation.

904.The Greek construction is compressed and uneven. The translation takes “the sun’s appearance through the haze” as what the second clause explains, and “falls all together” with the reflected sight. Wachsmuth notes that part of the phrase is absent from manuscript P; the wording printed in his text is retained.

905.The weather sign follows from the preceding claim that the reflecting cloud is close to becoming water. “Southern” and “northern” distinguish the positions of the mock suns in this explanation.

906.The Greek retains Wachsmuth’s brackets around the rejected article tas. The final distinction is between the uniform reflecting cloud of a mock sun and the uneven cloud responsible for the colored streaks called rods.