“I am very happy to say in this connection that the theory of a general levelling process, maintained by my learned colleague, is confirmed by the present condition of the planet Mars. That eminent geologist told us a few moments ago, that, owing to the continuous action of rivers, plains almost horizontal would constitute the final form of the earth’s surface. That is what has already happened in the case of Mars. The beaches near the sea are so flat that they are easily and frequently inundated, as every one knows. From season to season hundreds of thousands of square kilometers are alternately exposed or covered by a thin layer of water. This is notably the case on the western shores of the Kaiser sea. On the moon this levelling process has not taken place. There was not time enough for it; before its consummation, the air, the wind and the water had vanished. “It is then certain that, while the earth is destined to undergo a process of levelling, as my eminent colleague has so clearly explained, it will at the same time gradually lose the water which it now possesses. To all appearances, the latter process is now going on more rapidly than the former. As the earth loses its internal heat and becomes cold, crevasses will undoubtedly form, as in the case of the moon. The complete extinction of terrestrial heat will result in contractions, in the formation of hollow spaces below the surface, and the contents of the ocean will flow into these hollows, without being changed into vapor, and will be either absorbed or combined with the metallic rocks, in the form of ferric hydrates. The amount of water will thus go on diminishing indefinitely, and finally totally disappear. Plants, deprived of their essential constituent, will become transformed, but must at last perish. “The animal species will also become modified, but there will always be herbivora and carnivora, and the extinction of the former will involve, inevitably, that of the latter; and at last, the human race itself, notwithstanding its power of adaption, will die of hunger and of thirst, on the bosom of a dried-up world.