is the scene of some violent forms of action resembling, only much less violent, the processes at work in the sun, yet let it be remembered that there is much in the appearance of Jupiter which cannot readily be otherwise explained. It is very well to compare his belts, for instance, with our wind-zones-our trade and counter-trade regions. Such an explanation sounds highly plausible; and it has so long passed current, that we are apt to forget the circumstance that we have not a particle of evidence in its favour. To get trade-winds or counter trade-winds, we require currents of air travelling, in the first place, north and south, or nearly so; and again, to get such currents we require great differences of temperature, resulting in great disturbances of atmospheric equilibrium. The intense heat of our equatorial and tropical regions may well be understood to cause an indraught of cooler air from regions a thousand miles or so nearer the poles. But if a distance of ten thousand miles and more separated the cooler from the more heated regions, the indraught would be very much feebler. If we had two coiled springs, one a foot long and the other ten feet long, it is clear that a compression by some given amount-say one inch-would affect the shorter very much more than the longer; and, mutatis mutandis, the above-considered differences of temperature are very fairly illustrated by this relation. Now, Jupiter being more than ten times greater in all his linear dimensions than the earth, it is clear that we must have just such a diminution of all those effects of indraught

or overflow by which we explain our own trade and counter-trade winds. He rotates more swiftly, it is true; but against this may fairly be set the fact that he is five times farther from the sun, and (if other things are equal) must needs receive but a twenty-fifth part of the heat which, falling on the earth, rouses our winds into action. It seems to me amazing that, under these circumstances, the sun should ever have been regarded as the exciting cause of those processes which shape the atmospheric envelope of Jupiter into the bright and dusky zones.

For

The explanation obviously suggested (not necessarily, however, the correct one) is, that the formation of the belts of Jupiter is due to the violent uprush of vapours from vast depths below his visible surface. vapours thus flung upwards, coming as they would from regions nearer to Jupiter's centre and therefore moving more slowly, to regions farther away and therefore moving more rapidly (precisely as the rim of a wheel moves more rapidly than the middle of a spoke), would be left behind, and, as seen from a distant station, would form a trail, so to speak, lying, as the belts do, parallel to the planet's equator. Nor are we without evidence of the action of some such eruptive forces as are here suggested. For white spots, spoken of by the observers as specks, yet two or three thousand miles across at the least, have been seen from time to time, and but for a time, upon the belts; and these can in no way be interpreted so readily as by supposing them due to explosive action

casting up enormous masses of vapour into the higher regions of Jupiter's atmosphere.

Before concluding, I would remind the reader that the evidence here adduced is altogether independent of that which I have brought forward elsewhere. I have shown in my Other Worlds,' (1) that the equatorial bright belts both of Jupiter and Saturn are in no sense comparable with our zone of calms or doldrums, being persistently equatorial, whereas our zone of calms travels far to the north of the equator in summer, and far to the south in winter; (2) that the amount of light received from Jupiter, Saturn, and Uranus is very far in excess of the amount due to the size and position of these orbs a fact suggesting the theory that a portion of their light is inherent; and (3) that we have evidence of a very strong, nay, all but irresistible nature, to show that even the seeming figures of Jupiter and Saturn are liable to change. These and other remarkable circumstances recognised by astronomers, combined with the evidence adduced above, and the striking resemblance of the outer planets to the sun in the matter of mean density, do certainly seem to suggest in a very forcible manner that these outer planets are in a condition very different from that of our own earth; and though it may be going too far to say that they are actually minor or subordinate suns, yet such a view seems likely to be nearer to the truth than that which regards them as habitable worlds like our own.

Regarding Jupiter in this way, we need by no

tures.

means consider that he is never to be inhabited. The processes we see at work out yonder may be fitting him for the support of myriads of races of living creaFor anything we know to the contrary, he may be passing through stages which our own earth has long since passed through. In his case the processes of change may take up more time, indeed, but this is fitting when the vastness of his bulk is considered. For it must not be forgotten that light though his substance may be on the average, he has in him the materials for 300 globes such as our earth; that out of his substance every other planet now existing in the solar system might be fashioned, and yet abundant matter be left for making other worlds ; that, in fine, in whatever condition he subsists now, or at any future time, he must always be the noblest of all the members of the sun's family.

The St. Paul's Magazine for April, 1871.

L

SHOOTING-STARS, METEORS, AND

AEROLITES.

ON a calm, clear night, when

All the stars

Shine, and the immeasurable heavens

Break open to their highest,

the contemplation of the celestial vault raises in the least thoughtful mind vague suggestions of infinity, eternity, and omnipotence. A knowledge of the wonders which have been revealed by modern astronomical investigations, largely enhances these emotions. Looking into the starlit depths of heaven, the astronomer knows that the objects presented to him shine from distances so great, that not only are they inconceivable themselves, but that the very unit by which he attempts to gauge them is inconceivable. He knows that what he sees is not that which is, but that which was,-years ago as respects the nearer parts of the heaven-scape, but long ages ago, he doubts not, as respects faintly shining stars visible only by momentary scintillations. He has good reasons, indeed, for surmising that the diffused illumination, which, on the darkest night lights up the background of the view, had been travelling towards the earth myriads of ages before she had assumed her present state, or had been inhabited by races now