The sun in his daily course passes at various distances, sometimes above and sometimes below, the nearly stationary earth. Obviously it will at times pass actually behind it, and then the lunar spectator would behold the sublime spectacle of a total solar eclipse, and that under circumstances which render the phenomenon far more imposing than its counterpart can appear from the earth; for whereas, when we see the moon eclipse the sun, the nearly similar (apparent) diameters of the two bodies renders the duration of totality extremely short—at most 7 minutes—a lunar spectator, the earth appearing to him four times the diameter of the sun, and he and the earth being relatively stationary, would enjoy a view of the totality extending over several hours. During the passage of the solar disc behind that of the earth, a beautiful succession of luminous phenomena would be observed to follow from the refractions and dispersions which the sunbeams would suffer in passing tangentially through those parts of our atmospheric envelope which lie in their course; those, for instance, on the margin of the earth, as seen from the moon. As the sun passed behind the earth, the latter would be encircled upon the in-going side with a beautiful line of golden light, deepening in places to glowing crimson, due to the absorption, already spoken of, of all but the red and orange rays of the sun’s light by the vapours of our atmosphere. As the eclipse proceeded and totality came on, this ruddy glow would extend itself nearly, if not all, around the black earth, and so bright would it be, that the whole lunar landscape covered by the earth’s shadow would be illuminated with faint crimson light,[18] save, perhaps, in some parts of the far distance, upon which the earth had not yet cast its shadow, or off which the shadow had passed. Although the crimson light would preponderate, it would not appear bright and red alike all around the earth’s periphery. The circle of light would be, in fact, _the ring of twilight_ round our globe, and it would only appear red in those places where the atmosphere chanced to be in that condition favourable for producing what on earth we know as red sunset and sunrise. We know that the sun, even in clear sky, does not always set and rise with the beautiful red glow, which may be determined by merely local causes, and will therefore vary in different parts of the earth. Now a lunar spectator watching the sun eclipsed by the earth, would see, during totality and at a _coup d’œil_, every point around our world upon which the sun is setting on one side and rising upon the other. To every part of the earth around what is then the margin, as seen from the moon, the sun is upon the horizon, shining through a great thickness of atmosphere, reddening it, and being reddened by it wherever the vaporous conditions conduce to that colouration. And at all parts where these conditions obtain, the lunar