Page:Littell's Living Age - Volume 132.djvu/375

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spond with this view. I should be disposed to assign, as the reflective power of Jupiter (his albedo, as Zöllner calls it) about five hundred, or more than twice the reflective power of white sandstone, and thus to attribute about one-fifth of Jupiter's light to the planet's inherent lustre. (In Saturn's case Zöllner's observations are much less satisfactory — his measures indeed of the planet's total light were probably even more satisfactory than in Jupiter's case, but it is exceedingly difficult to take properly into account the effect of the ring-system, which, though very much foreshortened when Zöllner made his observations, must nevertheless have appreciably affected his results.) All the known facts accord well with this view.

Certainly the spectroscopic evidence recently obtained by Vogel, or rather the general spectroscopic evidence (for his results are not new) is not opposed, as he seems to imagine, to the theory that the actual surface of Jupiter is intensely hot. His argument is that, because dark lines are seen in the spectrum of Jupiter, which are known to belong to the absorption spectrum of aqueous vapor, the planet's surface cannot be intensely hot. But Jupiter's absorption spectrum belongs to layers of his atmosphere lying far above his surface. We can no more infer — nay, we can far less infer — the actual temperature of Jupiter's surface from the temperature of the layers which produce his absorption spectrum, than a being who approached our earth from without observing the low temperature of the air ten or twelve miles above the sea-level could infer thence the temperature of the earth's surface. There may be, in my opinion there almost always certainly are, layers of cloud several thousand miles deep between the surface we see and the real surface of the planet. I do not suppose that the inherent light referred to above as probably received from Jupiter, is light coming directly from his glowing surface, but the glow of cloud masses high above his surface, and illuminated by it, — perhaps even the glow of cloud-layers lit up by lower cloud-layers which themselves even may not receive the direct light emitted by his real surface.

To sum up, it appears to me, that a theory to which we are led by many effective and some apparently irresistible arguments, and against which no known facts appear to afford any argument of force, should replace the ordinary theory, originated in a haphazard way, and in whose favor no single argument of weight has ever been adduced. Since it appears, (1) that if the accepted theory of the development of our system is true, the large planets must of necessity be far younger that is hotter, than our earth and other small planets; (2) that if made of similar materials, those planets must of necessity be far denser than they actually are, unless they are very much hotter than the earth; (3) that the atmospheres (judging of their depth from the planet's appearance) would be compressed into solid and very dense matter under the planet's attraction unless exceedingly hot throughout their lower, layers; (4) that the belts and their chancres imply the uprush and downrush of heated masses of vapor through enormous depths of atmosphere; (5) that the cloud-belts neither change with the progress of the day nor of the year in the large planets, but in a manner in no way referrible to the sun, and are therefore presumably raised by the intense heat of the planet's own substance; (6) that so remarkable are the changes taking place in the atmospheres of Jupiter and Saturn, as appreciably (even at our enormous distance) to affect the figure of those planets; and (7) that the planets shine with more than two and a half times the brightness they would have if their visible surface were formed of even so lustrous a substance as white sandstone, — I think the conclusion is to all intents and purposes demonstrated that the planets Jupiter and Saturn really are in a state of intense heat If they ever are to be the abode of life, they will probably not be ready to subserve that purpose for hundreds of millions of years.

From The Fortnightly Review.



One special feature of what is called the Eastern Question is the direct and immediate connection into which it brings the earliest and the latest times of history. In the lands with which the Eastern Question is concerned, the lands between the Hadriatic and the Euxine — perhaps we should rather say the lands between the Hadriatic and the Euphrates — we are brought close to the very earliest times in a different way from anything to which we are used in western Europe. In western Europe earlier times have influenced later times in the ordinary way of cause and effect. In eastern Europe