26. We have here a number of circumstances which speak far more persuasively for a similarity of condition, in this planet and the Earth, than in any of the cases previously discussed. It is true, Mars is much smaller than the earth, and has not been judged worthy of the attendance of a satellite, although further from the Sun; but still, he may have been judged worthy of inhabitants by his Creator. Perhaps we are not quite certain about the existence of an atmosphere; and without such an appendage, we can hardly accord him tenants. But if he have inhabitants, let us consider of what kind they must be conceived to be, according to any judgment which we can form. The force of his gravity is so small, that we may allow his animals to be large, without fearing that they will break down by their own weight. In a planet so dense, they may very likely have solid skeletons. The ice about his poles will cumber the seas, cold even for the want of solar heat, as it does in our arctic and antarctic oceans; and we may easily imagine that these seas are tenanted, like those, by huge creatures of the nature of whales and seals, and by other creatures which the existence of these requires and implies. Or rather, since, as we have said, we must suppose the population of other planets to be more different from our existing population, than the population of other ages of our own planet, we may suppose the population of the seas and of the land of Mars, (if there be any, and if we are not carrying it too high in the scale of vital activity,) to differ from any terrestrial animals, in something of the same way in which the great land and sea saurians, or the iguanodon and dinotherium, differed from the animals which now live on the earth.