We have given our views respecting the various planets which constitute the Solar System;—views established, it would seem, by all that we know, of the laws of heat and moisture, density and attraction, organization and life. We have examined and reasoned upon the cases of the different planets separately. But it may serve to confirm this view, and to establish it in the reader's mind, if we give a description of the system which shall combine and connect the views which we have presented, of the constitution and peculiarities, as to physical circumstances, of each of the planets. It will help us in our speculations, if we can regard the planets not only as a collection, but as a scheme;—if we can give, not an enumeration only, but a theory. Now such a scheme, such a theory, appears to offer itself to us.

The planets exterior to Mars, Jupiter and Saturn especially, as the best known of them, appear, by the best judgment which we can form, to be spheres of water, and of aqueous vapour, combined, it may be, with atmospheric air, in which their cloudy belts float over their deep oceans. Mars seems to have some portion at least of aqueous atmosphere; the earth, we know, has a considerable atmosphere of air, and of vapour; but the Moon, so near to her mistress, has none.