But we could not expect that beauty and fertility would reign supreme throughout an entire world, and there was a time when, looking down from our lofty perch, we became aware that the trees had disappeared from our range of vision, and that the grass was tussocky and stunted. The change, to be sure, had been gradual, but with it had come the departure of the human residence, and of all animals, neither was there any water. It was clear enough that we were hovering upon the borders of a barren land, perhaps, even a desert. We looked to our water supply, and concluded there was enough to carry us over any ordinarily arid region, especially at the rapid rate at which we were traveling, and so settled ourselves down on deck to our cigars and fieldglasses. * * * * * We had been chatting along quite pleasantly, constantly scanning the horizon, when we became aware that the air was perceptibly warmer, and at the same time saw that even our scrubby patches of grass had been entirely supplanted by the sand, which lay thick and red beneath, with a peculiar luster. At long intervals there were rocks of the same color, indistinguishable, except from their elevation, and in their crevices grew a coarse, thorny plant, nearly as red as the rock itself. Dropping earthward, we found these plants greasy and bad smelling. At the same time we discovered that the ground was unpleasantly warm, and that the sand crawled, covering our footsteps as soon as made. We wanted to take some samples of this cactus-like leaf, but feared it might be poisonous and so let it alone. Gradually even this loathsome weed disappeared, and only the sand remained. It was clear that we had entered upon a desert, where nothing grew, and where nothing lived. True, there was no sun, but notwithstanding this, the air was hot and sultry. We were unable to account for this change in the temperature, and the heavy incinerated atmosphere, but the rapidity of our flight created a draught, which kept us fairly comfortable. The smoke from our cigars trailed rapidly astern, and then sank to the ground in a condensed form as if weight laden. We watched it with interest, puzzling over the cause, which Torrence thought might be some peculiar quality in the air, coupled to the strong draught of the vessel. Dropping to a lower level, and going astern, we were amazed to see a pale-blue, thread-like line marking our course in a path over the ground. It seemed incredible, but it was nothing more or less than a smoke path, formed and fed by our cigars. Not a breath of air disturbed its rectilinearity. It was a phenomenon neither of us could understand. We stood watching this for a long time, observing how the smoke, as we blew it from our mouths, would sweep earthward with the draught of the vessel, and then immediately be drawn out into the thin, blue, concentrated line described.