“Most of the country is highly volcanic, and there are numerous mountains, volcanoes and craters of all sizes. On many of these the greater part of the surface is covered with metallic deposits which throw upwards the strong reflections of the sun’s rays; these reflections are caught by the atmosphere which is in perceptible layers not seen from Earth. These layers maintain the same height above the ground, regular or irregular, the lower being about two miles deep, the next being a shade more dense, unlike the atmosphere of Earth, which is more dense as it approaches the ground. The reflection, therefore, readily penetrates the lighter and more transparent layer and, on striking the more dense, becomes refracted by it and is carried along in enormous streaks at the junction of the two, as from the surface of a mirror or from a silvery cloud, thus forming great rays which follow the curvature of the ground at a height of about two miles, and, partaking of the colour of the sun and being transparent, so colour the ground below them that on Earth there appears little difference except in brightness. We are just now sinking through that proceeding from Tycho, and you will be convinced that this explanation is correct by noticing that we cut off all the rays from beyond us on the shadow side. Now we are in the lower stratum, and you will see the rays proceeding for thousands of miles as before—we see them over our heads like a transparent golden cloud on which is a faint shadow of our vessel, though not sufficiently strong to be distinguishable from Earth. Now we have left the lower plane and are rising again; our dome has just cut through the rays, casting a long shadow like a triangle, the apex of which is our dome, and this shadow may appear to you as a faint line or pencilling of shade. In this place we have also measured the depth of the stratum from the ground and find it is exactly two miles, as elsewhere, so will you correct your present measurements to this. Earth-sighted instruments are in error because they must first penetrate through the fifty miles, or thereabouts, of Earth’s atmosphere, then travel through the thousands of miles of space minus the atmosphere, and have then to penetrate another and altogether different atmosphere, and Earth measurements at best are only comparative. It is impossible for you on Earth to see, measure, and understand as we do here, for you cannot allow for unbounded vacuum and these strange atmospheres without coming into them, especially as Earth measurements _in vacuo_ must necessarily be made through the flask or vessel bounding the vacuum, and consequently are not strictly reliable. We give you only what we verify by actual measurement and experiment made on the spot, and you may rely upon all details being correct. “We are now leaving Luna without landing and are going straight to Jupiter. Good-bye!” CHAPTER VI THE DOOMED PLANET