See Optics, Part III. sect. i. § 1.

Lunar Rainbow. The moon sometimes also exhibits the phenomenon of an iris, by the refraction of her rays in drops of rain in the night-time.

Aristotle says, he was the first that ever observed it; and adds, that it is never visible but at the time of full moon.

The lunar iris has all the colours of the solar, only fainter.

Marine Rainbow, the Sea-bow, is a phenomenon sometimes observed in a much agitated sea, when the wind, sweeping part of the tops of the waves, carries them aloft; so that the rays of the sun are refracted, &c. as in a common shower.