As I have decided to stay here upon Mars, and have just taken leave of my two dear old friends, I will now address a few last words to those who may read this record of our trip to Mars, and then seal up the packet ready for John to take with him.
In the course of my conversations with Merna's tutors, I learnt much about the past history of the Martian people; and they told me that it dates back to such a remote antiquity that, as compared with theirs, ours is only the history of an infancy!
Mars, being a much smaller globe than the earth, cooled down and became habitable æons before the earth reached that stage; and at the time when the earlier inhabitants of our world were living in woods and caves—slowly and painfully fashioning for themselves weapons and tools out of chipped flint-stones—there existed upon Mars a people who had then arrived at a full and vigorous civilisation.
What wonder then that, with all these past ages of development and the incentive which the present physical condition of the planet supplies them, the Martians of the present day are in all respects, whether physically, morally, or intellectually, far in advance of the inhabitants of our much younger, and therefore less developed, world!
The lessons to be learned from this, and from the physical conditions now prevailing on the planet, are very similar.
Mars, gradually, but inevitably, becoming a vast desert, and with the end of all things certain to arrive in a comparatively near future, pictures to us what must as inevitably be the fate of our own world ages hence, unless it come to an untimely end by some catastrophe.
As Professor Lowell has pointed out, we know we have an abundant supply of water at the present time, but we also know that, ages ago, the area of our world covered with water was immensely greater than it is now. From the very beginning of our world's existence the process of diminution of the water area has always gone on, and it will still go on—slowly, surely, and continually.
As an inevitable result of this decrease of water, and other natural conditions, vast areas of land on both sides of our tropical zones have become deserts; and it is a scientific certainty that this process of desertism will, and must continue, until it covers the whole world.
But, I think, the end will long be delayed, for the loss by desertism will, as it seems to me, for ages be compensated by the new and habitable land arising from areas now covered by water. The old sea-beds upon Mars are now the most fertile areas upon that planet.