There are many other objects of interest, which I could mention to you, but I must draw my letter to a close; I will therefore only just give you the names of a few of those dark hollows which you can see with the unaided eye when the full moon is shining brightly.
There is the "Sea of Tranquillity": its width from north to south is 432 miles, and from east to west 425 miles. There are also the "Sea of Serenity," the "Sea of Fogs," the "Frozen Sea," the "Sea of Vapours" and the "Gulf of Rainbows." This last named will appear to you of a greenish tint, and it is surrounded on nearly all sides with very lofty and steep mountains, some of them more than 15,000 feet high. Then there are the "Ocean of Storms," the "Gulf of Dew," and the "Sea of Humours." This last will also appear of a green tint; it is very level, and is 280 miles across.
Next come the "Sea of Nectar" and the "Sea of Fertility." All these were named "seas," because the ancient astronomers thought they contained water, and that they really were seas; but you are aware now that they contain no trace of water, so I need not inform you of that fact. And now dear cousin, I sincerely hope that what I have written will interest you, and if it does, and you will kindly let me know, I will write you another letter at some future time; but for the present I will say--Farewell!
Your faithful servant and attached cousin,
This comet, which last year excited so much interest, is supposed by some to be the same which appeared in the year 1737. If so, it is beyond the power of the human intellect to calculate the number of miles (millions upon millions) which it has travelled since that date; we may, however, in imagination, travel with it on one of its journeys.
Starting off then, as soon as it has made its perihelion passage, we are carried in the course of about six months to such a distance that this comparatively insignificant world (of which nevertheless we are all anxious to get a good slice) disappears entirely from our view, and the larger planets of this system are reduced to mere specks of light. The sun itself, which here scorches us at noonday, only appears there as a very minute star, just a small yellow speck. But meantime other suns, some of them of far greater magnitude and superior brilliancy than the sun we have left behind, gradually come into sight, and some of the "nebulæ," which appear to us here as so many bits of faint hazy light, some of them no larger than a crown piece, now appear to our unassisted vision in all the glorious majesty of suns and worlds and systems of worlds, all revolving round each other in the most regular and systematic order; for, as Milton says in _Paradise Lost_, "Order is Heaven's first law."