_Paraselenæ._ Mock moons, depending upon the causes which produce the solar image, or several examples of it, as frequently adorn the arctic sky. On the 1st of December, 1819, in the evening, while Parry’s expedition was in Winter Harbor, four paraselenæ were observed, each at the distance of 21½° from the true moon. One was close to the horizon, the other perpendicular above it, and the other two in a line parallel to the horizon. Their shape was like that of a comet, the tail being from the moon, the side of each toward the real orb being of a light orange color. During the existence of these paraselenæ, a halo appeared in a concentric circle round the moon, passing through each image. On the evening of March 30, 1820, about ten o’clock, the attention of Dr. Trail, at Liverpool, was directed by a friend to an unusual appearance in the sky, which proved to be a beautiful display of paraselenæ. The moon was then 35° above the southern horizon. The atmosphere was nearly calm, but rather cloudy, and obscured by a slight haze. A wide halo, faintly exhibiting the prismatic colors, was described round the moon as a centre, and had a small portion of its circumference cut off by the horizon. The circular band was intersected by two small segments of a larger circle, which if completed would have passed through the moon, and parallel to the horizon. These segments were of a paler color than the first mentioned circle. At the points of intersection appeared two pretty well defined luminous discs, equaling the moon in size, but less brilliant. The western paraselenæ had a tail or coma, which was directed from the moon, and the eastern also, but less clearly-defined. _The Rainbow._ The most glorious vision depending upon the decomposition, refraction, and reflection of light, by the vapor of the atmosphere reduced to fluid drops, is the well-known arch projected during a shower of rain upon a cloud opposite to the sun, displaying all the tints of the solar spectrum. The first marked approximation to the true theory of the rainbow occurs in a volume entitled _De Radiis Visus et Lucis_, written by Antonius de Dominis, Archbishop of Spalatro, published in the year 1611 at Venice. Descartes pursued the subject, and correctly explained some of the phenomena; but upon Newton’s discovery of the different degrees of refrangibility in the different colored rays which compose the sunbeam, a pencil of white or compounded light, the cause of the colored bands in the rainbow, of the order of their position, and of the breadth they occupy, was at once apparent. The bow is common to all countries, and is the sign of the covenant of promise to all people, that there shall no more be such a wide-spread deluge as that which the sacred narrative records.