There is, strictly speaking, but little similarity between this sketchy trifle and the very celebrated and very beautiful "Moon-story" of Mr. Locke- but as both have the character of hoaxes, (although one is in the tone of banter, the other of downright earnest) and as both hoaxes are on the same subject, the moon- the author of "Hans Phaall" thinks it necessary to say, in self-defence, that his own jeu-d'esprit was published, in the Southern Literary Messenger, about three weeks previously to the appearance of Mr. L's in the New York "Sun." Fancying a similarity which does not really exist, some of the New York papers copied "Hans Phaall," and collated it with the Hoax- with the view of detecting the writer of the one in the writer of the other. By late accounts from Rotterdam, that city seems to be in a high state of philosophical excitement. Indeed, phenomena have there occurred of a nature so completely unexpected - so entirely novel - so utterly at variance with preconceived opinions - as to leave no doubt on my mind that long ere this all Europe is in an uproar, all physics in a ferment, all reason and astronomy together by the ears. date), a vast crowd of people, for purposes not specifically mentioned, were assembled in the great square of the Exchange in the well-conditioned city of Rotterdam. The day was warm- unusually so for the season - there was hardly a breath of air stirring; and the multitude were in no bad humor at being now and then besprinkled with friendly showers of momentary duration, that fell from large white masses of cloud which chequered in a fitful manner the blue vault of the firmament. Nevertheless, about noon, a slight but remarkable agitation became apparent in the assembly: the clattering of ten thousand tongues succeeded; and, in an instant afterward, ten thousand faces were upturned toward the heavens, ten thousand pipes descended simultaneously from the corners of ten thousand mouths, and a shout, which could be compared to nothing but the roaring of Niagara, resounded long, loudly, and furiously, through all the environs of Rotterdam.