We know too little yet of their condition to venture far in such speculations. Still, taking the matter as a whole, there seem many reasons to incline us to the idea that each of the four greater outside planets may be a kind of secondary half-cooled sun to his satellites, helping to make up to them for the small amount of light and heat which they can obtain from the far-off sun. CHAPTER XX. COMETS AND METEORITES. A curious discovery has been lately made. It is that some sort of mysterious tie seems to exist between comets and meteorites. For a long while this was never suspected. How should it be? The comets, so large, so airy, so light; the meteorites, so small, so solid, so heavy,--how could it possibly be supposed that the one had anything to do with the other? But supposings often have to give in to facts. Astronomers are gradually becoming convinced that there certainly is a connection between the two. Strange to say, comets and meteorites occupy--sometimes, at least--the very same pathways in the heavens, the very same orbits round the sun. A certain number of meteorite systems are now pretty well known to astronomers as regularly met by our earth at certain points in her yearly journey. Some of these systems or rings have each a comet belonging to it--not merely journeying near, but actually in its midst, on the same orbit. Perhaps it would be more correct to say that the meteorites belong to the comet, than that the comet belongs to the meteorites. We tread here on uncertain ground; for whether the meteorites spring from the comet, or whether the comet springs from the meteorites, or whether each has been brought into existence independently of the other, no one can at present say. Though it is out of our power to explain the kind of connection, yet a connection there plainly is. So many instances are now known of a comet and a meteorite ring traveling together that it is doubtful whether any such ring could be found without a comet in its midst. By and by the doubt may spring up whether there ever exists a comet without a train of meteorites following him. Among the many different meteorite rings which are known, two of the most important are the so-called August and November systems. Of these two, the November system must claim our chief attention. Not that we are at all sure of these being the most important meteorite rings in the Solar System. On the contrary, as regards the November ring, we have some reason to think that matters may lie just the other way.