below this, are found outside of Mars, appears to indicate, that the _planet-making_ powers which were efficacious to this distance from the sun, and which produced the great globe of the Earth, were, beyond this point, feebler; so that they could only give birth to smaller masses; to planetoids, to satellites, and to meteoric stones. Perhaps we may describe this want of energy in the planet-making power, by saying, that at so great a distance from the central fire, there was not heat enough to melt together these smaller fragments into a larger globe;[6] or rather, when they existed in a nebular, perhaps in a gaseous state, that there was not heat enough to keep them in that state, till the attraction of the parts of all of them had drawn them into one mass, which might afterwards solidify into a single globe. The tendency of nebular matter to separate into distinct portions, which may afterwards be more and more detached from each other, so as to break the nebulous light into patches and specks, appears to be seen in the structure of the resolvable nebulæ, as we have already had occasion to notice. And according to the view we are now taking, we may conceive such patches, by further cooling and concentration, to remain luminous as comets, and perhaps shooting stars; or to become opaque as planets, planetoids, satellites, or meteoric stones. And here we may call to mind what we have already said, that the meteoric stones consist of the same elements as those of the earth, combined by the same laws; and thus appear to bring us a message from the other solid planets, that they also have the same elements and the same chemical forces as the earth has.