Imperceptibly, from century to century, the earth’s surface had become levelled. The action of the rain, snow, frost and solar heat upon the mountains, the waters of torrents, rivulets and rivers, had slowly carried to the sea the débris of every continental elevation. The bottom of the sea had risen, and in nine million years the mountains had almost entirely disappeared. Meanwhile, the planet had grown old faster than the sun; the conditions favorable to life had disappeared more rapidly than the solar light and heat. This conception of the planet’s future conforms to our present knowledge of the universe. Doubtless, our logic is radically incomplete, puerile even, in comparison with the real and eternal Truth, and might be justly compared with that of two ants talking together about the history of France. But, confessing the modesty which befits the finite in presence of the infinite, and acknowledging our nothingness as compared with the universe, we cannot avoid the necessity of appearing logical to ourselves; we cannot assume that the abdication of reason is a better proof of wisdom than the use of it. We believe that an intelligent order presides over the universe and controls the destiny of worlds and their inhabitants; that the larger members of the solar system must last longer than the lesser ones, and, consequently, that the life of each planet is not equally dependent upon the sun, and cannot, therefore, continue indefinitely, any more than the sun itself. Moreover, direct observation confirms this general conception of the universe. The earth, an extinct sun, has cooled more rapidly than the sun. Jupiter, so immense, is still in its youth. The moon, smaller than Mars, has reached the more advanced stages of astral life, perhaps even has reached its end. Mars, smaller than the earth, is more advanced than the earth and less so than the moon. Our planet, in its turn, must die before Jupiter, and this, also, must take place before the sun becomes extinct. Consider, in fact, the relative sizes of the earth and the other planets. The diameter of Jupiter is eleven times that of the earth, and the diameter of the sun about ten times that of Jupiter. The diameter of Saturn is nine times that of the earth. It seems to us, therefore, natural to believe that Jupiter and Saturn will endure longer than our planet, Venus, Mars or Mercury, those pigmies of the system! Events justified these deductions of science. Dangers lay in wait for us in the immensity of space; a thousand accidents might have befallen us, in the form of comets, extinct or flaming suns, nebulæ, etc. But the planet did not perish by an accident. Old age awaited the earth, as it waits for all other things, and it grew old faster than the sun. It lost the conditions necessary for life more rapidly than the central luminary lost its heat and its light.