“That is true. This car I have with me is my ordinary carriage at home. It is a railroad car as you see by the flanges on the wheels. Railroads with us are public free highways, built and maintained by the state. They have from four to twelve tracks. Every person who is qualified by his education and training to manage a car is furnished with one by the state. The propelling power is nothing but gravity either in attraction or repulsion, the former being used on down grades and the latter on up grades, the car having rollers that hook under a flange at the top of the rail to prevent the car from rising bodily from the track.
“The surface of our planet is very rough, but still the grading for roads is light, as it is possible to ascend grades of 100 per cent or even steeper. Level grades on our roads are always avoided, and in districts where this cannot be done, we use electric roads.
“The cars are so constructed that different parts are electrically insulated from each other, by which means a part of the car can be placed under the influence of attraction and the rest under that of repulsion. This is done on down grades. The weight of the load and of part of the car pulling down and the weight of the rest of the car holding back. It is always arranged to have the car heavier than its load, and the driver can regulate the force used by balancing one against the other, so that a car of many tons shall press on the rails with the weight of only a very few pounds. Thus the wear and tear on road beds and rails is almost nothing and the roads are practically everlasting.”
CHAPTER III.
The Moon and Its People.
“I am amazed,” said I, “to learn that the moon is inhabited and by a race apparently more advanced than our own. Our astronomers have assured us that the moon is a desolate played out barren world without air or water; totally unfit for inhabitants.”
“The astronomers could only report what they could see, and the side of the moon visible from the earth is as they describe it, but they have never seen the further side and never will, for that side is always turned from the earth. But the population of the moon is not far from half that of the earth and the people live in greater comfort. But there is no population living on the surface on the hemisphere facing the earth—I see this puzzles you,” he said.
It certainly did. “Do you mean that the Lunarians live under ground?” I inquired.
“I will explain. The moon is a much lighter body than the earth bulk for bulk, a cubic yard of it containing on an average only six tenths as much matter as an average yard of earth. The reason of this is that a very large part of the moon’s bulk is made up of interstices, caves and openings. Now it is a remarkable fact that the hemisphere of the moon facing the earth is much lighter than the further one, so much so that the center of gravity is 33 miles further from this side of the moon than from the further side. This fact has been suspected by some of your astronomers. The consequence of it is that the sea has all gone to the further hemisphere, and the near hemisphere is in the highest place, about 33 miles above the level of the sea. It is much as if a concave cap, the material of which is 33 miles thick at the center and tapers to zero all round the rim, were fitted on to a sphere. This rim is at the edge of the moon, as seen from the earth. Our atmosphere like yours, gets lighter as we ascend and is too thin to support life at a height of five miles, so that the great plateaus of our hither hemisphere are over 20 miles higher than any appreciable atmosphere. So you can see the impossibility of life on the hither surface of the moon if you reflect a moment what the conditions would be on a mundane plateau 33 miles above the sea level. Your highest mountains are only between five and six miles high, and you know the impossibility of either vegetable or animal life at even that altitude.
“On the earth such elevations are regions of perpetual snow, and the hither surface of the moon would be such a region if it possessed water and an atmosphere. But while the surface on this side is uninhabitable, there are immense tracts of underground space, that have been converted into habitable territory. This underground country lies so far below the surface that it is practically near the sea level throughout. It is approached at all parts of the rim of the cap just described, and there are many thousands of tunnels entering it all round this rim, especially in the equatorial parts of the moon. A great amount of labor has been expended, not only on these entrances, but on the internal cavities to which they lead; but compared with the work performed for us by nature, our own labor is but an insignificant item—hardly so much as the labor of your race in fitting up the earth for your residence. The entrances are all volcanic craters, and the vast cavities to which they lead, were excavated long ages ago by volcanic action. The material blown out of the volcanoes, mostly fell upon the hither side of the moon increasing the bulk of the cap; most of the volcanoes being on this side. But even the material thrown from the lateral regions was drawn this way by the attraction of the earth and after describing a longer or shorter curve, fell on the hither side of the moon.