observation had led me to conceive as possible. The satellites were no longer mere points or tiny discs, but distinct moons, with surfaces marked like that of our own satellite, though far less mountainous and broken, and, as it seemed to me, possessing a distinct atmosphere. I am not sure that there is not a visible difference of brightness among them, not due to their size but to some difference in the reflecting power of their surfaces, since the distance of all from the Sun is practically equal. That Jupiter gives out some light of his own, a portion of which they may possibly reflect in differing amount according to their varying distance, is believed by Martial astronomers; and I thought it not improbable. The brilliant and various colouring of the bands which, cross the face of the giant planet was wonderfully brought out; the bluish-grey around the poles, the clear yellowish-white light of the light bands, probably belts of white cloud, contrasted signally the hues—varying from deep orange-brown to what was almost crimson or rose-pink on the one hand and bright yellow on the other—of different zones of the so-called dark belts. On the latter, markings and streaks of strange variety suggested, if they failed-to prove, the existence of frequent spiral storms, disturbing, probably at an immense height above the surface, clouds which must be utterly unlike the clouds of Mars or the Earth in material as well as in form and mass. These markings enabled us to follow with clear ocular appreciation the rapid rotation of this planet. In the course of half-an-hour several distinct spots on different belts had moved in a direct line across a tenth of the face presented to us—a distance, upon the scale of the gigantic image, so great that the motion required no painstaking observation, but forced itself upon the notice of the least attentive spectator. The belief of Martial astronomers is that Jupiter is not by any means so much less dense than the minor planets as his proportionately lesser weight would imply. They hold that his visible surface is that of an enormously deep atmosphere, within which lies, they suppose, a central ball, not merely hot but more than white hot, and probably, from its temperature, not yet possessing a solid crust. One writer argues that, since all worlds must by analogy be supposed to be inhabited, and since the satellites of Jupiter more resemble worlds than the planet itself, which may be regarded as a kind of secondary sun, it is not improbable that the former are the scenes of life as varied as that of Mars itself; and that infinite ages hence, when these have become too cold for habitation, their giant primary may have gone through those processes which, according to the received theory, have fitted the interior planets to be the home of plants, animals, and, in two cases at least, of human beings.