De la Rive, from whose admirable treatise upon Electricity we have borrowed our general views, and whose theory we have attempted to illustrate in this paper, concludes that the aurora borealis is a phenomenon which has its seat in the atmosphere, and consists in the production of a luminous ring of greater or less diameter, having for its centre the magnetic pole. Experiment shows, as we have seen, that, on bringing about in rarefied air the reunion of the two electricities, near the pole of a powerful artificial magnet, a small luminous ring is produced, similar to that which constitutes the aurora borealis, and animated by a similar movement of rotation. The aurora borealis would be due, consequently, to electric discharges taking place in the polar regions between the positive electricity of the atmosphere and the negative electricity of the earth. These electric discharges taking place constantly, but with intensities varying according to the state of the atmosphere, the aurora borealis should be a daily phenomenon, more or less intense, consequently visible at greater or less distances, but only when the nights are clear,--which is perfectly in accordance with observation. The aurora australis presents precisely the same phenomena as the aurora borealis, and is explained, consequently, in the same manner. THE PROFESSOR AT THE BREAKFAST-TABLE. WHAT HE SAID, WHAT HE HEARD, AND WHAT HE SAW. A young fellow, born of good stock, in one of the more thoroughly civilized portions of these United States of America, bred in good principles, inheriting a social position which makes him at his ease everywhere, means sufficient to educate him thoroughly without taking away the stimulus for vigorous exertion, and with a good opening in some honorable path of labor, is the finest sight our private satellite has had the opportunity of inspecting on the planet to which she belongs. In some respects it was better to be a young Greek. If we may trust the old marbles,--my friend with his arm stretched over my head, above there, (in plaster of Paris,) or the discobolus, whom one may see at the principal sculpture gallery of this metropolis,--those Greek young men were of supreme beauty. Their close curls, their elegantly set heads, column-like necks, straight noses, short, curled lips, firm chins, deep chests, light flanks, large muscles, small joints, were finer than anything we ever see. It may well be questioned whether the human shape will ever present itself again in a race of such perfect symmetry. But the life of the youthful Greek was local, not planetary, like that of the young American. He had a string of legends, in place of our Gospels. He had no printed books, no newspaper, no steam caravans, no forks, no soap, none of the thousand cheap conveniences which have become matters of necessity to our modern civilization. Above all things, if he aspired to know as well as to enjoy, he found